A system and method are described herein employing a plurality of distributed transmitting antennas to create locations in space with zero RF energy. In one embodiment, when M transmit antennas are employed, it is possible to create up to (M−1) points of zero RF energy in predefined locations. In one embodiment of the invention, the points of zero RF energy are wireless devices and the transmit antennas are aware of the channel state information (CSI) between the transmitters and the receivers. In one embodiment, the CSI is computed at the receivers and fed back to the transmitters. In another embodiment, the CSI is computed at the transmitter via training from the receivers, assuming channel reciprocity is exploited. The transmitters may utilize the CSI to determine the interfering signals to be simultaneously transmitted. In one embodiment, block diagonalization (BD) precoding is employed at the transmit antennas to generate points of zero RF energy.

Prior art multi-user wireless systems may include only a single base station or several base stations.
A single WiFi base station (e.g., utilizing 2.4 GHz 802.11b, g or n protocols) attached to a broadband wired Internet connection in an area where there are no other WiFi access points (e.g. a WiFi access point attached to DSL within a rural home) is an example of a relatively simple multi-user wireless system that is a single base station that is shared by one or more users that are within its transmission range. If a user is in the same room as the wireless access point, the user will typically experience a high-speed link with few transmission disruptions (e.g. there may be packet loss from 2.4 GHz interferers, like microwave ovens, but not from spectrum sharing with other WiFi devices), If a user is a medium distance away or with a few obstructions in the path between the user and WiFi access point, the user will likely experience a medium-speed link. If a user is approaching the edge of the range of the WiFi access point, the user will likely experience a low-speed link, and may be subject to periodic drop-outs if changes to the channel result in the signal SNR dropping below usable levels. And, finally, if the user is beyond the range of the WiFi base station, the user will have no link at all.
When multiple users access the WiFi base station simultaneously, then the available data throughput is shared among them. Different users will typically place different throughput demands on a WiFi base station at a given time, but at times when the aggregate throughput demands exceed the available throughput from the WiFi base station to the users, then some or all users will receive less data throughput than they are seeking. In an extreme situation where a WiFi access point is shared among a very large number of users, throughput to each user can slow down to a crawl, and worse, data throughput to each user may arrive in short bursts separated by long periods of no data throughput at all, during which time other users are served. This "choppy" data delivery may impair certain applications, like media streaming.
Adding additional WiFi base stations in situations with a large number of users will only help up to a point. Within the 2.4 GHz ISM band in the U.S., there are 3 non-interfering channels that can be used for WiFi, and if 3 WiFi base stations in the same coverage area are configured to each use a different non-interfering channel, then the aggregate throughput of the coverage area among multiple users will be increased up to a factor of 3. But, beyond that, adding more WiFi base stations in the same coverage area will not increase aggregate throughput, since they will start sharing the same available spectrum among them, effectually utilizing time-division multiplexed access (TDMA) by "taking turns" using the spectrum. This situation is often seen in coverage areas with high population density, such as within multi-dwelling units. For example, a user in a large apartment building with a WiFi adapter may well experience very poor throughput due to dozens of other interfering WiFi networks (e.g. in other apartments) serving other users that are in the same coverage area, even if the user's access point is in the same room as the client device accessing the base station. Although the link quality is likely good in that situation, the user would be receiving interference from neighbor WiFi adapters operating in the same frequency band, reducing the effective throughput to the user.
Current multiuser wireless systems, including both unlicensed spectrum, such as WiFi, and licensed spectrum, suffer from several limitations. These include coverage area, downlink (DL) data rate and uplink (UL) data rate. Key goals of next generation wireless systems, such as WiMAX and LTE, are to improve coverage area and DL and UL data rate via multiple-input multiple-output (MIMO) technology. MIMO employs multiple antennas at transmit and receive sides of wireless links to improve link quality (resulting in wider coverage) or data rate (by creating multiple non-interfering spatial channels to every user). If enough data rate is available for every user (note, the terms "user" and "client" are used herein interchangeably), however, it may be desirable to exploit channel spatial diversity to create non-interfering channels to multiple users (rather than single user), according to multiuser MIMO (MU-MIMO) techniques. See, e.g., the following references:    G. Caire and S. Shamai, "On the achievable throughput of a multiantenna Gaussian broadcast channel," IEEE Trans. Info. Th., vol. 49, pp. 1691-1706, July 2003.    P. Viswanath and D. Tse, "Sum capacity of the vector Gaussian broadcast channel and uplink-downlink duality," IEEE Trans. Info. Th., vol. 49, pp. 1912-1921, August 2003.    S. Vishwanath, N. Jindal, and A. Goldsmith, "Duality, achievable rates, and sum-rate capacity of Gaussian MIMO broadcast channels," IEEE Trans. Info. Th., vol. 49, pp. 2658-2668, October 2003.    W. Yu and J. Cioffi, "Sum capacity of Gaussian vector broadcast channels," IEEE Trans. Info. Th., vol. 50, pp. 1875-1892, September 2004.    M. Costa, "Writing on dirty paper," IEEE Transactions on Information Theory, vol. 29, pp. 439-441, May 1983.    M. Bengtsson, "A pragmatic approach to multi-user spatial multiplexing," Proc. of Sensor Array and Multichannel Sign. Proc. Workshop, pp. 130-134, August 2002.    K.-K. Wong, R. D. Murch, and K. B. Letaief, "Performance enhancement of multiuser MIMO wireless communication systems," IEEE Trans. Comm., vol. 50, pp. 1960-1970, December 2002.    M. Sharif and B. Hassibi, "On the capacity of MIMO broadcast channel with partial side information," IEEE Trans. Info. Th., vol. 51, pp. 506-522, February 2005.
For example, in MIMO 4×4 systems (i.e., four transmit and four receive antennas), 10 MHz bandwidth, 16-QAM modulation and forward error correction (FEC) coding with rate ¾ (yielding spectral efficiency of 3 bps/Hz), the ideal peak data rate achievable at the physical layer for every user is 4×30 Mbps=120 Mbps, which is much higher than required to deliver high definition video content (which may only require ˜10 Mbps). In MU-MIMO systems with four transmit antennas, four users and single antenna per user, in ideal scenarios (i.e., independent identically distributed, i.i.d., channels) downlink data rate may be shared across the four users and channel spatial diversity may be exploited to create four parallel 30 Mbps data links to the users. Different MU-MIMO schemes have been proposed as part of the LTE standard as described, for example, in 3GPP, "Multiple Input Multiple Output in UTRA", 3GPP TR 25.876 V7.0.0, March 2007; 3GPP, "Base Physical channels and modulation", TS 36.211, V8.7.0, May 2009; and 3GPP, "Multiplexing and channel coding", TS 36.212, V8.7.0, May 2009. However, these schemes can provide only up to 2× improvement in DL data rate with four transmit antennas. Practical implementations of MU-MIMO techniques in standard and proprietary cellular systems by companies like ArrayComm (see, e.g., ArrayComm, "Field-proven results", http://www.arraycomm.com/serve.php?page=proof) have yielded up to a ˜3× increase (with four transmit antennas) in DL data rate via space division multiple access (SDMA). A key limitation of MU-MIMO schemes in cellular networks is lack of spatial diversity at the transmit side. Spatial diversity is a function of antenna spacing and multipath angular spread in the wireless links. In cellular systems employing MU-MIMO techniques, transmit antennas at a base station are typically clustered together and placed only one or two wavelengths apart due to limited real estate on antenna support structures (referred to herein as "towers," whether physically tall or not) and due to limitations on where towers may be located. Moreover, multipath angular spread is low since cell towers are typically placed high up (10 meters or more) above obstacles to yield wider coverage.
Other practical issues with cellular system deployment include excessive cost and limited availability of locations for cellular antenna locations (e.g. due to municipal restrictions on antenna placement, cost of real-estate, physical obstructions, etc.) and the cost and/or availability of network connectivity to the transmitters (referred to herein as "backhaul"). Further, cellular systems often have difficulty reaching clients located deeply in buildings due to losses from walls, ceilings, floors, furniture and other impediments.
Indeed, the entire concept of a cellular structure for wide-area network wireless presupposes a rather rigid placement of cellular towers, an alternation of frequencies between adjacent cells, and frequently sectorization, so as to avoid interference among transmitters (either base stations or users) that are using the same frequency. As a result, a given sector of a given cell ends up being a shared block of DL and UL spectrum among all of the users in the cell sector, which is then shared among these users primarily in only the time domain. For example, cellular systems based on Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA) both share spectrum among users in the time domain. By overlaying such cellular systems with sectorization, perhaps a 2-3× spatial domain benefit can be achieved. And, then by overlaying such cellular systems with a MU-MIMO system, such as those described previously, perhaps another 2-3× space-time domain benefit can be achieved. But, given that the cells and sectors of the cellular system are typically in fixed locations, often dictated by where towers can be placed, even such limited benefits are difficult to exploit if user density (or data rate demands) at a given time does not match up well with tower/sector placement. A cellular smart phone user often experiences the consequence of this today where the user may be talking on the phone or downloading a web page without any trouble at all, and then after driving (or even walking) to a new location will suddenly see the voice quality drop or the web page slow to a crawl, or even lose the connection entirely. But, on a different day, the user may have the exact opposite occur in each location. What the user is probably experiencing, assuming the environmental conditions are the same, is the fact that user density (or data rate demands) is highly variable, but the available total spectrum (and thereby total data rate, using prior art techniques) to be shared among users at a given location is largely fixed.
Further, prior art cellular systems rely upon using different frequencies in different adjacent cells, typically 3 different frequencies. For a given amount of spectrum, this reduces the available data rate by 3×.
So, in summary, prior art cellular systems may lose perhaps 3× in spectrum utilization due to cellularization, and may improve spectrum utilization by perhaps 3× through sectorization and perhaps 3× more through MU-MIMO techniques, resulting in a net 3*3/3=3× potential spectrum utilization. Then, that bandwidth is typically divided up among users in the time domain, based upon what sector of what cell the users fall into at a given time. There are even further inefficiencies that result due to the fact that a given user's data rate demands are typically independent of the user's location, but the available data rate varies depending on the link quality between the user and the base station. For example, a user further from a cellular base station will typically have less available data rate than a user closer to a base station. Since the data rate is typically shared among all of the users in a given cellular sector, the result of this is that all users are impacted by high data rate demands from distant users with poor link quality (e.g. on the edge of a cell) since such users will still demand the same amount of data rate, yet they will be consuming more of the shared spectrum to get it.
Other proposed spectrum sharing systems, such as that used by WiFi (e.g., 802.11b, g, and n) and those proposed by the White Spaces Coalition, share spectrum very inefficiently since simultaneous transmissions by base stations within range of a user result in interference, and as such, the systems utilize collision avoidance and sharing protocols. These spectrum sharing protocols are within the time domain, and so, when there are a large number of interfering base stations and users, no matter how efficient each base station itself is in spectrum utilization, collectively the base stations are limited to time domain sharing of the spectrum among each other. Other prior art spectrum sharing systems similarly rely upon similar methods to mitigate interference among base stations (be they cellular base stations with antennas on towers or small scale base stations, such as WiFi Access Points (APs)). These methods include limiting transmission power from the base station so as to limit the range of interference, beamforming (via synthetic or physical means) to narrow the area of interference, time-domain multiplexing of spectrum and/or MU-MIMO techniques with multiple clustered antennas on the user device, the base station or both. And, in the case of advanced cellular networks in place or planned today, frequently many of these techniques are used at once.
But, what is apparent by the fact that even advanced cellular systems can achieve only about a 3× increase in spectrum utilization compared to a single user utilizing the spectrum is that all of these techniques have done little to increase the aggregate data rate among shared users for a given area of coverage. In particular, as a given coverage area scales in terms of users, it becomes increasingly difficult to scale the available data rate within a given amount of spectrum to keep pace with the growth of users. For example, with cellular systems, to increase the aggregate data rate within a given area, typically the cells are subdivided into smaller cells (often called nano-cells or femto-cells). Such small cells can become extremely expensive given the limitations on where towers can be placed, and the requirement that towers must be placed in a fairly structured pattern so as to provide coverage with a minimum of "dead zones", yet avoid interference between nearby cells using the same frequencies. Essentially, the coverage area must be mapped out, the available locations for placing towers or base stations must be identified, and then given these constraints, the designers of the cellular system must make do with the best they can. And, of course, if user data rate demands grow over time, then the designers of the cellular system must yet again remap the coverage area, try to find locations for towers or base stations, and once again work within the constraints of the circumstances. And, very often, there simply is no good solution, resulting in dead zones or inadequate aggregate data rate capacity in a coverage area. In other words, the rigid physical placement requirements of a cellular system to avoid interference among towers or base stations utilizing the same frequency results in significant difficulties and constraints in cellular system design, and often is unable to meet user data rate and coverage requirements.
So-called prior art "cooperative" and "cognitive" radio systems seek to increase the spectral utilization in a given area by using intelligent algorithms within radios such that they can minimize interference among each other and/or such that they can potentially "listen" for other spectrum use so as to wait until the channel is clear. Such systems are proposed for use particularly in unlicensed spectrum in an effort to increase the spectrum utilization of such spectrum.
A mobile ad hoc network (MANET) (see http://en.wikipedia.org/wiki/Mobile_ad_hoc_network) is an example of a cooperative self-configuring network intended to provide peer-to-peer communications, and could be used to establish communication among radios without cellular infrastructure, and with sufficiently low-power communications, can potentially mitigate interference among simultaneous transmissions that are out of range of each other. A vast number of routing protocols have been proposed and implemented for MANET systems (see http://en.wikipedia.org/wiki/List_of_ad-hoc_routing_protocols for a list of dozens of routing protocols in a wide range of classes), but a common theme among them is they are all techniques for routing (e.g. repeating) transmissions in such a way to minimize transmitter interference within the available spectrum, towards the goal of particular efficiency or reliability paradigms.
All of the prior art multi-user wireless systems seek to improve spectrum utilization within a given coverage area by utilizing techniques to allow for simultaneous spectrum utilization among base stations and multiple users. Notably, in all of these cases, the techniques utilized for simultaneous spectrum utilization among base stations and multiple users achieve the simultaneous spectrum use by multiple users by mitigating interference among the waveforms to the multiple users. For example, in the case of 3 base stations each using a different frequency to transmit to one of 3 users, there interference is mitigated because the 3 transmissions are at 3 different frequencies. In the case of sectorization from a base station to 3 different users, each 180 degrees apart relative to the base station, interference is mitigated because the beamforming prevents the 3 transmissions from overlapping at any user.
When such techniques are augmented with MU-MIMO, and, for example, each base station has 4 antennas, then this has the potential to increase downlink throughput by a factor of 4, by creating four non-interfering spatial channels to the users in given coverage area. But it is still the case that some technique must be utilized to mitigate the interference among multiple simultaneous transmissions to multiple users in different coverage areas.
And, as previously discussed, such prior art techniques (e.g. cellularization, sectorization) not only typically suffer from increasing the cost of the multi-user wireless system and/or the flexibility of deployment, but they typically run into physical or practical limitations of aggregate throughput in a given coverage area. For example, in a cellular system, there may not be enough available locations to install more base stations to create smaller cells. And, in an MU-MIMO system, given the clustered antenna spacing at each base station location, the limited spatial diversity results in asymptotically diminishing returns in throughput as more antennas are added to the base station.
And further, in the case of multi-user wireless systems where the user location and density is unpredictable, it results in unpredictable (with frequently abrupt changes) in throughput, which is inconvenient to the user and renders some applications (e.g. the delivery of services requiring predictable throughput) impractical or of low quality. Thus, prior art multi-user wireless systems still leave much to be desired in terms of their ability to provide predictable and/or high-quality services to users.
Despite the extraordinary sophistication and complexity that has been developed for prior art multi-user wireless systems over time, there exist common themes: transmissions are distributed among different base stations (or ad hoc transceivers) and are structured and/or controlled so as to avoid the RF waveform transmissions from the different base stations and/or different ad hoc transceivers from interfering with each other at the receiver of a given user.
Or, to put it another way, it is taken as a given that if a user happens to receive transmissions from more than one base station or ad hoc transceiver at the same time, the interference from the multiple simultaneous transmissions will result in a reduction of the SNR and/or bandwidth of the signal to the user which, if severe enough, will result in loss of all or some of the potential data (or analog information) that would otherwise have been received by the user.
Thus, in a multiuser wireless system, it is necessary to utilize one or more spectrum sharing approaches or another to avoid or mitigate such interference to users from multiple base stations or ad hoc transceivers transmitting at the same frequency at the same time. There are a vast number of prior art approaches to avoiding such interference, including controlling base stations' physical locations (e.g. cellularization), limiting power output of base stations and/or ad hoc transceivers (e.g. limiting transmit range), beamforming/sectorization, and time domain multiplexing. In short, all of these spectrum sharing systems seek to address the limitation of multiuser wireless systems that when multiple base stations and/or ad hoc transceivers transmitting simultaneously at the same frequency are received by the same user, the resulting interference reduces or destroys the data throughput to the affected user. If a large percentage, or all, of the users in the multi-user wireless system are subject to interference from multiple base stations and/or ad hoc transceivers (e.g. in the event of the malfunction of a component of a multi-user wireless system), then it can result in a situation where the aggregate throughput of the multi-user wireless system is dramatically reduced, or even rendered non-functional.
Prior art multi-user wireless systems add complexity and introduce limitations to wireless networks and frequently result in a situation where a given user's experience (e.g. available bandwidth, latency, predictability, reliability) is impacted by the utilization of the spectrum by other users in the area. Given the increasing demands for aggregate bandwidth within wireless spectrum shared by multiple users, and the increasing growth of applications that can rely upon multi-user wireless network reliability, predictability and low latency for a given user, it is apparent that prior art multi-user wireless technology suffers from many limitations. Indeed, with the limited availability of spectrum suitable for particular types of wireless communications (e.g. at wavelengths that are efficient in penetrating building walls), it may be the case that prior art wireless techniques will be insufficient to meet the increasing demands for bandwidth that is reliable, predictable and low-latency.
Prior art related to the current invention describes beamforming systems and methods for null-steering in multiuser scenarios. Beamforming was originally conceived to maximize received signal-to-noise ratio (SNR) by dynamically adjusting phase and/or amplitude of the signals (i.e., beamforming weights) fed to the antennas of the array, thereby focusing energy toward the user's direction [14-20]. In multiuser scanarios, beamforming can be used to suppress interfering sources and maximize signal-to-interference-plus-noise ratio (SINR) [21-23]. For example, when beamforming is used at the receiver of a wireless link, the weights are computed to create nulls in the direction of the interfering sources [15]. When beamforming is used at the transmitter in multiuser downlink scenarios, the weights are calculated to pre-cancel inter-user interfence and maximize the SINR to every user [21-23]. Alternative techniques for multiuser systems, such as BD precoding [24-25], compute the precoding weights to maximize throughput in the downlink broadcast channel.

This patent is subject to a terminal disclaimer.

Interference management, handoff, power control and link adaptation in distributed-input distributed-output (DIDO) communication systems


A method is disclosed comprising drawing air into a robotic vapor device from an airstream of a heating, ventilation, and air conditioning (HVAC) system, exposing the drawn air to a sensor to detect one or more constituents in the drawn air, determining measurement data for the one or more constituents of the drawn air via the sensor, determining one or more vaporizable materials to vaporize based on the measurement data, transmitting an instruction to the HVAC system to continue providing the airstream, and dispensing a vapor comprised of the one or more vaporizable materials into the airstream.

Consumers purchase and use a wide variety of air fresheners or the like, with very little or no information about the compounds that these products are emitting into the breathable air space and that they are exposing their bodies to. At the same time, there is widespread interest in indoor air quality as more time is spent indoors and many people suffer allergies or chemical sensitivities to various materials. Presently, consumers have no convenient way to really know and control what compounds they are exposing themselves to by using air fresheners or similar products. Moreover, consumers have no convenient way, or no way at all, to control which compound, or which mix of compounds, are emitted into an air space for air freshening, air treatment, personal therapy, recreation, or for any other purpose.
It would be desirable, therefore, to develop new technologies for such applications, that overcomes these and other limitations of the prior art, and enhances the utility of air treatment in residences, offices, commercial spaces, industrial spaces, and so forth.

Electronic vapor and analysis with HVAC integration


A rotary distributor fuel pumping apparatus includes a cam actuated pumping plunger which delivers fuel to a plurality of outlets in turn during successive inward movements. A spill valve is provided which can be opened when fluid pressure is applied to a piston to spill fuel from the bore. An auxiliary plunger delivers fluid under pressure which can be applied to the piston through a control valve. The control valve includes an annular spring loaded component which is moved by the fluid pressure and an angularly adjustable rod which is surrounded by the component. The rod is provided with a helical groove and the component with a slot and when these are brought into communication fluid under pressure is applied to the piston.

Summary of the Invention
This invention relates to a fuel pumping apparatus for supplying fuel to an internal combustion engine and of the kind comprising a rotary distributor member journalled in a pump body and arranged to be driven in use in timed relationship with the associated engine, a pumping plunger mounted in a bore in the distributor member, cam means for imparting inward movement to the plunger, a delivery passage in the distributor member in communication with the bore, the delivery passage registering in turn with a plurality of outlets in the pump body during successive inward movements of the pumping plunger, a spill valve operable to allow fuel to spill from the bore, a fluid pressure operable piston for actuating the spill valve, an auxiliary plunger carried by the distributor member, the auxiliary plunger being operated at the same time as the pumping plunger, and a control valve including a fluid pressure operable component movable by the fluid delivered by said auxiliary plunger, said control valve controlling the application of fluid under pressure to said piston.
The object of the present invention is to provide an apparatus of the kind specified in a simple and convenient form.
According to the invention the control valve at a predetermined position in the movement of said component opens to apply the fluid under pressure delivered by said auxiliary plunger to said piston.
According to a further feature of the invention said control valve comprises an outer fixed member defining a cylindrical bore, an inner member in the form of an angularly adjustable rod, said component being of annular form and being slidably located between the inner and outer members, said annular component at one end being exposed to the pressure of fluid delivered by said auxiliary plunger, resilient means for opposing the movement of the component and valve means defined by the component and the rod whereby after a predetermined axial movement of the component against the action of the resilient means and depending on the relative angular position of the component and the rod, the valve means opens to allow the fluid pressure developed by the auxiliary plunger to act on said piston.
According to a still further feature of the invention the rod is coupled to a governor mechanism and the component is angularly adjustable in accordance with an engine operating parameter.


A recognition model set is generated. A technique is described to take advantage of the logarithm likelihood of real data for cross entropy to measure the mismatch between a training data and a training data derived model, and compare such type of mismatches between class dependent models and class independent model for evidence of model replacement. By using change of cross entropies in the decision of adding class independent Gaussian Mixture Models (GMMs), the good performance of class dependent models is largely retained, while decreasing the size and complexity of the model.

Speech recognition is the process by which computers analyze sounds and attempt to characterize them as particular letters, words, or phrases. Generally, a speech recognition system is "trained" with many phoneme examples. A phoneme is a basic unit of sound in a given lexicon. For example, it is generally agreed that the English language possesses approximately 50 unique phonemes. Each phoneme may include several variations in its pronunciation, referred to as allophones. In the example speech recognition system there are approximately 700 allophones. FIG. 1 shows two sets of training data (22A, 24A) and resulting data model set for the prior art and the embodiments of the invention. In FIG. 1, diagonally shaded circles represent phonemes 20A grouped into two sets 22A and 24A. A single set 26A groups all phonemes and both sets 22A and 24A.
A speech recognition system examines various features from each allophone example by mathematically modelling its sounds on a multidimensional landscape using multiple Gaussian distributions. Models of the allophones or at least close representations of the allophones are represented by shaded circles such as 20B. These are referred to as allophone models but could equally be called acoustic models, phoneme models, data models, or models in the description. Models 20B are grouped into two sets 22B (vertically shaded models) and 24B (horizontally shaded models) corresponding to original sets of phonemes 22A and 24A. A single set 26B groups class independent models (dotted shading) of all the allophones, that is, within the set 26A.
Once allophone models of allophones are created, input speech to be recognized is sliced into small samples of sound. Each sample is converted into a multidimensional feature vector by analyzing the same features as previously used to examine the allophones. Speech recognition is then performed by statistically matching the feature vector with the closest allophone model. Thus, the accuracy, or word error rate (WER), of a speech recognition system is dependent on how well the allophone models of allophones represent the sound samples input by the system.
Class dependent models based on single class training data are generally known to get better classification accuracy than the class independent allophone models based on all-class training data. In the circumstances of speech recognition, separate class dependent female and male allophones model sets, can yield improved recognition accuracy over a set of class (in this case gender) independent allophone models. There are two categories of existing methods to make use of class specific allophone models. One use of such models is to build one system with just female models and one system with just male models. At test time, samples are decoded using both systems in a two-pass approach. While such class specific systems provide better speech recognition results, they generally require too much computing power and resources to be practical in many real-world applications. The other category of method is based on a "determining" operation which determines if there is a difference in model information is between the female model and the male model. If the difference in model information is insignificant, a "training" operation creates an independent allophone model based on the female set of training data and the male set of training data when female and male models are replaced with class independent models, the computation and resources required can be substantially reduced. However the difference in the model information between the two class specific models does not reflect the change of model likelihood, which directly influences the recognition accuracy.
U.S. patent publication 2005/0049872 discloses measuring the difference between one class specific allophone model and another class specific allophone model and to replace them both with a single class independent model when the difference in allophone space is small. The difference is called the Kullback Leibler distance. See FIG. 1, where a resultant model set contains a combination of class independent models (dotted) and class dependent models (horizontally and vertically shaded). This method has some shortcomings. Firstly, since the decision to replace takes no account of whether the replacement model is suitable when replacing, the replacement can have a negative impact on recognition accuracy. Secondly, Kullback Leibler distance requires a Monte Carlo method for the calculation, which in turn requires generation of pseudo samples. If the number of samples is small, then the calculation is not reliable; if the number of samples is large then large resources are needed for the computation. Thirdly, the Kullback Leibler distance is not applicable to more than two classes. (e.g. four models: children, old people, female, and male specific models are under the consideration for replacement by a general model). Since the Kullback Leibler distance in the model information can only be applied to exactly two models, the issues of more than two specific models need to be solved with new methods. Fourthly, the method does not allow for the replacement decision to be adjusted at run-time.

Data modeling of class independent recognition models

International Business Machines Corporation


A metal-reinforced layered composite includes at least one intermediate metal layer. The intermediate metal layer includes at least two at least partially overlapping metal foils which are joined to one another in an overlap region by at least one weld seam. There are no leakage channels and/or no continuous leakage channels at the weld seam of the metal foils in the longitudinal extent of the overlap region. At least one of the weld seams may have a course which at least at one point has a direction component at right angles to the longitudinal extent of the overlap region of the metal foils. The intermediate metal layer may be provided with at least one passage in the overlap region of the metal foils. A gasket, a gasket sheet, a metal layer and a method of manufacturing a layered composite are also provided.

The present invention relates to metal-reinforced layered composites based on one or more soft materials, in particular to gaskets, gasket sheets and metal layers, as well as to a method of manufacturing the same.
The metal-reinforced layered composites according to the invention have at least one intermediate metal layer. The intermediate metal layer includes at least two at least partially overlapping metal foils which are joined to one another in an overlap area. The invention makes it possible to manufacture large-dimension laminated panels which, as gasket sheets, meet the highest technical standards. Gaskets, in particular flat gaskets in annular form, as shown in FIG. 9, are manufactured by being punched out of the gasket sheets.
Layered composites based on one or more soft materials are often reinforced with thin metal foils to improve their mechanical stability. The soft materials used in layered composites include thermoplastics, above all PTFE-based thermoplastics, and elastomers which may be reinforced with inorganic or organic fibers, such as e.g. aramide, carbon, ceramic and metal fibers. The compressive strength of the soft materials may also be increased by fillers such as e.g. silicon dioxide, aluminum oxide, carbon or graphite in powder form. Furthermore, inorganic and compression-proof materials such as, in particular, mica and graphite may be used as soft materials. Foils and laminates manufactured from expanded graphite, which are jointly referred to below as graphite foils, are also used as special graphite variants. Corresponding layered composites are described, for example, in German Published, Non-Prosecuted Patent Application DE 198 04 283 A1, corresponding to U.S. application Ser. No. 09/244,836 now U.S. Pat. No. 6,258,457. Besides simple metal foils it is also possible to use spiked metal sheets as intermediate metal layers. The spiked metal sheets have spikes which may extend to one or to both sides. In the simplest case, a metal-reinforced layered composite based on one or more soft materials includes a metal foil layer embedded in two soft material layers.
The metal foils are commercially available only up to a limited web width which depends on the material and foil thickness. It is necessary to join together at least two metal foils for the intermediate metal layer to manufacture metal-reinforced layered composites or gasket sheets of such dimensions that the web width of the available metal foils is insufficient to allow the intermediate metal layers of the layered composites to be removed from a metal foil web in one piece.
Until now, such commercial-scale metal-reinforced layered composites have been realized by overlapping metal foil webs at their lateral ends and effecting joining together either by gluing, mechanical interlocking or welding, such as by resistance roll seam welding. The metal foils used for the intermediate metal layer in the layered composites mostly have a small thickness, such as e.g. 50 xcexcm or 100 xcexcm, in order to make it easy to punch gaskets out of the layered composites. Therefore, it is generally impossible to carry out butt welding of the metal foils under industrial production conditions.
A method and an apparatus for welding together butt-jointed sheets is known from German Published, Non-Prosecuted Patent Application DE 195 29 542 A1. That method is based on the sheets to be welded together initially overlapping in their marginal region. The overlapping end zones of the marginal regions are then cut off with mutually aligned cut edges, the cut edges are then made to abut one another and finally the cut edges are welded to one another by a laser beam. As a result of that time sequence of process steps, it is impossible, particularly with long webs which are moving, to guarantee that the cut edges at right angles to the direction of motion of the webs will still be in the same position when they reach the welding location as they are when they are cut. Even minor external influences, such as temperature variations or vibrations, as well as tiny undulations in the thin metal foils, may lead to gaps between the cut edges of the webs or a renewed overlap of the webs. A remedy therefor is provided according to the method described in the German Published, Non-Prosecuted Patent Application mentioned above. That is accomplished in the case of long webs and/or large web widths by a guide body which stabilizes the position of the webs relative to one another. That guide body guides the sheet metal webs, which are to be welded together, in such a way that the lateral edge of the webs lies against the base of a slot in the guide body. However, in the case of the metal foils which are used in the layered composites of the gasket sheets, their low thickness of, at times, well below 0.25 mm precludes such guidance by a guide body on a commercial scale. As the metal foil webs move through the guide body, high forces at the base of the guide slot act upon the lateral edge of the metal foil. Due to low stability thereof, those forces are sufficiently high to cause buckling very rapidly and therefore to cause the edge of the foil to be destroyed or even to caused the metal foil to tear. That might be counteracted by a very narrow guide slot but that might lead to the metal foil becoming stuck in the guide slot and therefore possibly tearing. The use of such a guide slot may, moreover, cause the metal foil web to be displaced in such a way as to form a slight undulation or fold in the metal foil web which causes the foil web guidance downstream of the guide slot to run off in an uncontrolled manner. It is therefore impossible to use the butt-welding method described in German Published, Non-Prosecuted Patent Application DE 195 29 542 A1 for the particularly thin metal foils such as are normally used in layered composites for gasket elements.
Heretofore, various techniques have been used to join metal foils for intermediate metal layers for gasket sheets, wherein foil ends overlap in the region of the joint.
In one instance, joining is effected by applying an adhesive, such as e.g. epoxy resin, which hardens, between the overlapping foil ends. In that case, the adhesive is mostly applied over the entire overlap region on at least one of the metal foils which are to be joined. Gluing together of the metal foils has the drawback of only permitting gaskets which are manufactured from layered composites including intermediate metal layers joined in that manner to be used in an extremely limited temperature range. The reason for that limitation is that, at higher temperatures, the adhesive softens and/or is partially thermally decomposed. On one hand, that may lead in the gaskets to the metal foils shearing off more easily from one another at their glued junction points under stress, such as tensile forces in the direction of the metal foils and compressive forces at right angles to the intermediate metal layers, thereby reducing the mechanical stability of the gaskets. Only porous, leaky, pyrolized residues of the adhesive remain in the overlap region between the glued metal foil ends as a result of thermal decomposition of the adhesive. If the pores being produced in the adhesive merge with one another, that may produce extensive continuous channels in the glue residue. The channels in a gasket may even extend from one edge of the gasket to the other and lead to a substantial increase of the leakage rate of the gasket because a medium, which is to be sealed off, may escape out of the gasket through those channels. Such channels, which extend from one gasket edge to the other gasket edge, are referred to below as leakage channels of the gasket. Gaskets having intermediate metal layers, which include metal foils glued to one another, therefore tend to have higher leakage rates at increased temperatures. The use of gaskets, which have intermediate metal layers being formed of metal foils glued to one another, is additionally restricted to media which do not attack the adhesive. That is because otherwise, as a result of the medium attacking the adhesive, on one hand, a shearing of the metal foils under stress is once again possible and therefore the mechanical stability of the gaskets is reduced. On the other hand, the decomposition of the adhesive by the aggressive medium being sealed off may, just as with high temperatures, lead to the formation of leakage channels in the adhesive. As a result, the sealing action of the gasket is no longer guaranteed. In order to provide for the universal use of gaskets manufactured from layered composites, which include intermediate metal layers composed of at least two joined metal foils, it is therefore essential for the joining of the metal foils of the intermediate metal layers to be effected without introducing further media such as, for example, adhesives into the gaskets.
One possible way of joining two metal foils to form a metal layer without the use of additional media is that of pure mechanical interlocking of the foils, which still entails an overlap of the foil ends. In that case, the lateral ends of the metal foils to be joined are interlocked in such a way that the layered composites have the same mechanical stability as in the case of the use of single-piece intermediate metal layers. Such a joint is based on pure contact between the metal foils. However, gaskets manufactured from layered composites having intermediate metal layers joined in such a manner may have much higher leakage rates than gaskets manufactured from layered composites having single-piece intermediate metal layers.
When welding metal foils together according to the prior art, the ends of the metal foils are conveyed in an overlapping manner and joined together by applying heat through the metal foils lying one above the other in the overlap region. The weld seam, i.e. the region where the metal foils are cohesively joined by the applied heat, runs in the longitudinal extent of the overlap region. In that case, the width of the overlap region is generally far greater than the width of the applied weld seam. Through the use of intermediate metal layers welded together in that manner it is possible to achieve a mechanical stability of the layered materials equivalent to that of corresponding layered materials, which include exclusively single-piece intermediate metal layers.
In principle, all known welding methods such as pressure welding, fusion welding, resistance welding and beam welding may be used as a welding method. In that case, continuous and discontinuous methods are used. Resistance welding in the form of spot welding (discontinuous welding) and roll seam welding (continuous welding) is used, above all, with sheets disposed in an overlapping manner. In the case of spot welding, the welding electrodes are placed onto the two metal foils which are to be welded together in the middle of the overlap region and then the foils are melted and joined through the use of a current pulse. In the case of roll seam welding, use is made of disc-shaped contact rollers, through which the overlapping ends of the foil webs are drawn. The result is a linear weld seam which extends in the middle of the overlap region. A central position is selected for welding spots or weld seams in order to guarantee that during welding the welding electrodes or contact rollers are in contact over their entire width with the two metal foils. Otherwise, too high a surface current may lead to the metal foils being burnt away at the welding point. It is moreover also possible to use laser beam welding to join the metal foils in their overlap region. In that case, the energy of the laser beam is absorbed in the form of heat by the metal foils, with the result that the metal foils fuse. In order to guarantee reliable and easy fusion of the metal foils, the laser beam should be positioned in the middle of the overlap region and the two overlapping metal foil webs should be moved relative to the stationary laser. It is thereby possible to produce a linear, cohesive weld seam in the overlap region of the foils.
However, occasionally, considerably higher leakage rates have been measured in gaskets manufactured from layered composites, which included intermediate metal layers joined by welding, as compared to corresponding gaskets, which included exclusively single-piece metal reinforcements. That is also evident from Tables 1 and 2 provided below. In those tables, the leakage rates of gaskets manufactured from layered composites, that included exclusively single-piece intermediate metal layers (Comparative Examples 1/1 and 2/1), are compared with the leakage rates of gaskets manufactured from layered composites, which had intermediate metal layers including at least two at least partially overlapping metal foils and produced by linear weld seams in the overlap region of the foils (Comparative Examples 1/2 and 2/2). As is immediately apparent, gaskets with linearly welded intermediate metal layers show a sealing behavior which is far inferior to that which is technically possible with single-piece intermediate metal layers.
As is apparent from the above, there are many ways of approaching the manufacture of intermediate metal layers for layered composites, in which a plurality of metal foils are joined. However, not one of those approaches has made it possible to also use layered composites with such intermediate metal layers to manufacture gaskets possessing the same properties as previously known gaskets that include exclusively single-piece intermediate metal layers. In particular, that problem imposes limits on the dimensions of layered composites and therefore of gaskets as well.
It is accordingly an object of the invention to provide a layered composite with a welded intermediate metal layer, a gasket, a gasket sheet, a metal layer and a method of manufacturing a layered composite, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provide high-quality, metal-reinforced layered composites based on one or more soft materials with at least one intermediate metal layer including at least two joined metal foils. The layered composites may be used to manufacture gaskets possessing the same properties as gaskets manufactured from corresponding layered composites containing exclusively single-piece intermediate metal layers. Methods of manufacturing corresponding layered composites use intermediate metal layers composed of at least two joined metal foils.
The expression xe2x80x9chigh-qualityxe2x80x9d stands, inter alia, for high temperature stability and media resistance as well as high mechanical stability. However, the comparison of the properties of corresponding metal-reinforced layered composites with and without intermediate metal layers manufactured by joining at least two metal foils, relates above all to the leakage rates of gaskets manufactured from the layered composites.
A further object of the present invention is to provide large-sized and inexpensive metal-reinforced layered composites based on one or more soft materials, in particular gasket sheets, which possess the same properties as metal-reinforced layered composites, that previously were conventionally manufactured with single-piece intermediate metal layers. In particular, gaskets manufactured from the large-sized layered composites are to have the same leakage rates as gaskets which were previously manufactured from the conventional layered composites. In order to achieve this object, as already mentioned above, it is necessary for the large-sized layered composites to contain intermediate metal layers which have been manufactured by joining at least two metal foils.
A further object of the invention has, moreover, been to provide gasket sheets from which it is possible to punch out single-piece gaskets, the dimensions of which go beyond the previously available dimensions. The gaskets should nevertheless possess the same properties as the previously available single-piece gaskets of smaller dimensions, particularly with reference to the leakage rates of the gaskets. In order to achieve this object, gasket sheets are required which have dimensions beyond the previously available dimensions without thereby adversely influencing the properties of the gaskets punched out of the gasket sheets.
With the foregoing and other objects in view there is provided, in accordance with the invention, a metal-reinforced layered composite based on at least one soft material, comprising at least one intermediate metal layer, at least one of the intermediate metal layers manufactured by joining at least two at least partially overlapping metal foils with at least one weld seam, and at each weld seam provided in the layered composite and joining two metal foils, there are no leakage channels and/or no continuous leakage channels in a longitudinal extent of the overlap region.
With the objects of the invention in view there is also provided, a method of manufacturing a metal-reinforced layered composite based on at least one soft material, which comprises joining at least partially overlapping metal foils of intermediate metal layers by welding the foils together along a longitudinal direction of an overlap region, at least once, in such a way that in the overlap region between the foils to be welded together, no open regions and/or no continuous open regions arise in the longitudinal extent of the overlap region.
According to the invention, the weld seam is to be directed in the overlap region in such a way that the existence of leakage channels, or at least the existence of continuous leakage channels, in the overlap region is ruled out. This is not guaranteed with a linear weld seam according to the prior art. In that case, non-welded excess lengths of metal foil extending in the longitudinal direction of the overlap region are produced in the overlap region. It is not possible to fill the volume between the excess lengths of metal with the soft material coating of the intermediate layer which is typically provided in the layered composites. As a result, in the case of a linear weld seam, there are open regions at the weld seam in the overlap region between the metal foils, which extend along the overlap region parallel to the weld seam and which, in the event of a use of the layered material as a gasket sheet, act as leakage channels parallel to the weld seam, that are not interrupted. Such leakage channels are similarly to be observed in an intermediate metal layer in which two metal foils are joined by mechanical interlocking. In that case too, excess lengths of metal arise in the region of the interlock and may not be sealed by soft material layers, with the result that open leakage channels are produced along the interlock.
The above-described continuous leakage channels are not produced in the layered composites according to the invention. As a result, leakage rates are achieved for gaskets made from the layered composites according to the invention which match those of gaskets made from layered composites with exclusively single-piece intermediate metal layers, as the test results shown further below verify.
In accordance with another feature of the invention, the welding together of the metal foils may be effected in such a way that the length of the non-continuous leakage channels at the weld seams along the longitudinal extent of the overlap region does not exceed a maximum length of 25 mm. The maximum length of the non-continuous leakage channels at the weld seams along the longitudinal extent of the overlap region is preferably between 0.5 mm and 5 mm, and between 1 and 2 mm in a particularly preferred manner.
In accordance with a further feature of the invention, the metal-reinforced layered composites made from one or more soft materials may, at their outwardly-directed flat sides, additionally be completely covered with and joined to a gas-proof foil made from an organic polymer.
In accordance with an added feature of the invention, at least one of the weld seams may have a shape, which at least at one point has a direction component at right angles to the longitudinal extent of the overlap region of the metal foils. This direction component of the shape of the weld seam, that is provided at least at that point, at right angles to the longitudinal extent of the overlap region, is produced by effecting the welding along a line which has a direction component at right angles to the longitudinal extent of the overlap region of the metal foils.
In the context of the present invention, the line along which the welding is effected, that is also referred to as the welding line, is the line along which the welding apparatus is conveyed relative to the metal foils, wherein the welding apparatus and/or the metal foils move with clearance.
In accordance with an additional feature of the invention, the welding together of the at least partially overlapping metal foils may be effected continuously, but alternatively may be provided intermittently or in a pulsed manner. In the continuous welding mode, the metal foils may be joined by weld seams which extend without interruption along the overlap region. In such a case, the weld seam fully coincides with the line along which the welding is effected. In the intermittent or discontinuous welding mode, the weld seams have at least one interruption of the weld seam along the welding line and therefore along the longitudinal extent of the overlap region. In particular, this also includes pulsed welding, whereby a welding operation is effected only at specific time intervals while the welding apparatus is travelling along the welding line. The result in this case is an interrupted weld seam, which only partially coincides with the welding line.
In accordance with yet another feature of the invention, the welding line, along which the welding of the metal foils is effected, may in particular have a periodic shape along the longitudinal extent of the overlap region of the metal foils. In such a case, the shape of the weld seam may, for example, be sinusoidal, meander-like, zigzag or stepped. The periodic length of the weld seam in such a case also determines the maximum length of the open regions between metal foils in their overlap region in the direction of the longitudinal extent of the overlap region, i.e. the maximum length of the non-continuous leakage channels along the weld seam. Thus, it is also proposed that gaskets, which are manufactured from the layered composites according to the invention, are required to have a gasket width which is greater than the periodic length of the weld seam in order not to have any open leakage channels. Therefore, given a periodic shape of the weld seams, the periodic length is usually selected so as to be less than 25 mm. Preferably, when welding with a periodic shape of the weld seam, a periodic length of between 0.5 and 5 mm is selected. In a particularly preferred manner periodic lengths of between 1 and 2 mm are selected. It is likewise possible, when welding the metal foils together through the use of weld seams with a periodic shape, for the periodic length to vary along the overlap region.
In accordance with yet a further feature of the invention, the metal foils, in webs, are preferably displaced continuously at a constant speed relative to a stationary welding apparatus. The welding of the metal foils in the context of the present invention may be effected by all suitable, known welding methods, e.g. resistance welding or laser beam welding. The welding is, however, preferably effected by laser beam. The weld seam is therefore preferably a laser weld seam. Laser beam welding is preferably effected by deflecting the laser beam in an oscillating manner from a center line. It is possible to adjust the shape, the thickness, the transverse extent, i.e. the maximum total extent of the welding line at right angles to the longitudinal extent of the overlap region, and the periodic length of the weld seam, by selecting the amplitude, frequency, focal position and power of the laser beam and the web speed of the metal foils. A further configuration is possible in that welding is effected continuously or in a pulsed manner.
In accordance with yet an added feature of the invention, prior to being welded together, the metal foils are disposed so as to overlap at least partially. The width of the overlap region in the present case should be substantially constant over the entire foil web length. The width of the overlap region of the metal foils may vary from section to section as a result of external influences such as temperature variations and/or vibrations or other influences. A further possibility is that the metal foils merely abut one another in one section. The metal foils would then only partially overlap. Therefore, with the metal-reinforced layered composites according to the invention, the joining of the individual metal foils which jointly form an intermediate metal layer may be effected in such a way that the metal foils at their mutually adjacent marginal regions partially or completely overlap and the foil ends also partially directly abut one another. The maximum width of the overlap region of the foils is usually set at less than 10 mm. The maximum width of the overlap region should be preferably between 0.2 mm and 2 mm, and in a particularly preferred manner between 0.5 mm and 1 mm.
In accordance with yet an additional feature of the invention, it is also possible for the metal foils first to be mechanically interlocked, before then being welded together. All of the leakage channels resulting from interlocking are then interrupted by such measures.
In accordance with again another feature of the invention, the transverse extent of the weld seam is, inter alia, even in the case of a periodic shape of the weld seam, greater than or equal to the maximum width of the overlap region. The transverse extent of the weld seam is, in a preferred manner, 1 to 2 times, and in a particularly preferred manner 1.1 to 1.5 times, the maximum width of the overlap region of the metal foils. In order to produce such a weld seam, the sum of the transverse extent of the welding line plus the width of the weld seam during welding has to be likewise greater than or equal to, or in a preferred manner 1 to 2 times and in a particularly preferred manner 1.1 to 1.5 times, the maximum transverse extent of the overlap region of the metal foils.
In accordance with again a further feature of the invention, in the case, for example, of a sinusoidal periodic weld seam, the transverse extent of the weld seam, upon implementation of the laser beam welding method preferred according to the invention, is equal to the transverse extent of the welding line, i.e. the lateral deflection amplitude, plus the width of the weld seam. In the case of a linear weld seam, the transverse extent of the weld seam would correspond exactly to the width of the weld seam.
In accordance with again an added feature of the invention, if, in the case of the metal-reinforced layer ed materials according to the invention, the welding together of the metal foils which form the intermediate metal layers is effected entirely or partially in pulsed-mode operation, then, in order to prevent leakage channels in the overlap region of the metal foils along the longitudinal direction of the overlap region, the width of the individual welding spots is to be selected in such a way that they at least partially overlap in their extent. The pulsed-mode operation of the laser can, e.g. given a constant pulse cycle and uniform feed of the metal foils relative to the welding apparatus, lead to welding spots along the welding line which are situated at a constant distance apart from one another along the longitudinal extent of the overlap region. The welding line itself may have a periodic shape, e.g. in the manner described above. In this case, for example, as well as with other welding lines which the metal-reinforced layered composites according to the invention include, individual successive welding spots are mutually offset in the width direction of the overlap region. Since the individual welding spots overlap in the present case, these individual welding spots therefore form a weld seam which extends over the entire width of the overlap region. In particular, such welding together of the metal foils may be effected in such a way that successive welding spots are positioned alternately on one or the other side in the direction of the width of the overlap region. In other words, the welding apparatus swings back and forth from welding spot to welding spot over the entire width of the overlap region.
In accordance with again an additional feature of the invention, the weld seam may in particular also include individual spots, the diameter of which is greater than or equal to the maximum width of the overlap region of the metal foils. This may be effected, for example, by resistance spot welding or pulsed laser beam welding.
In accordance with still another feature of the invention, the thickness of the weld seam, e.g. in the case of spot welding, may be greater than or equal to or approximately 1 to 2 times the maximum width of the overlap region of the metal foils. However, the thickness of the weld seam is preferably 0.25 to 0.9 mm and particularly preferably 0.4 to 0.7 mm.
In accordance with still a further feature of the invention, the weld seam may also have a linear course parallel to the longitudinal extent of the overlap region of the metal foils. The welding of such a weld seam is then effected likewise along a linear welding line parallel to the longitudinal extent of the overlap region of the metal foils. When two metal foils are joined at least partially exclusively by such a weld seam, with a layered composite according to the invention, the width of this one weld seam has to be greater than the maximum width of the overlap region. On one hand, this weld seam produced in a welding operation has a planar configuration, with the overlapping region of the metal foils being fully welded together. Such a form of the weld seam may, on the other hand, also be achieved e.g. by a sinusoidal welding line driven in the laser beam welding method, with the oscillating frequency being set so high that the temporally successive seams come very close to and/or touch one another or overlap.
The present invention also includes embodiments in which the metal foils are welded together in the following manner: (a) a plurality of linear, juxtaposed weld seams are directed in the longitudinal extent of the overlap region and overlap, with the total width of the resultant total weld seam being greater than or equal to the maximum width of the overlap region, and with the welding being effected in a plurality of welding operations, and (b) a linear weld seam is combined with at least one weld seam having a shape, which at least at one point, includes a direction component at right angles to the longitudinal extent of the overlap region of the metal foils, and with the direction component of the last-mentioned weld seam being greater than or equal to the width of the overlap region of the metal foils at that point. Procedure (b) has the advantage of permitting very thin metal foils to be welded together. First, the at least partially overlapping foils are welded together by a linear weld seam with a low energy input and therefore with low distortion. The existing leakage channels are subsequently closed, for example, through the use of a sinusoidal weld seam.
In accordance with still an added feature of the invention, the welded intermediate metal layer may also be provided with at least one passage in the overlap region of the metal foils, wherein the weld seam itself may follow a linear welding line along the longitudinal extent of the overlap region or may alternatively have any shape such as was previously described above for the metal-reinforced layered composites according to the invention. This passage is greater than or at least equal to the maximum width of the overlap regions of the metal foils. The passages are closed by the soft material layers, which lie adjacent the intermediate metal layers and completely fill the opening of the passage. The result of this filling with the gas-proof soft materials is that there are no gaps in the overlap region of the metal foils in the region of the passages. Thus, possible continuous leakage channels are avoided and the maximum length of leakage channels, which are still possible in the overlap region and have a limited extent in the direction of the longitudinal extent of the overlap region, extends from passage to passage.
In accordance with still an additional feature of the invention, the metal foils are preferably provided in the overlap region with numerous passages so that the overlap region includes passages at intervals, preferably at constant intervals, along the overlap region. The maximum spacing of the passages along the overlap region is usually at most 25 mm, preferably in the region of between 1 mm and 10 mm, and particularly preferably in the region of between 2 mm and 5 mm.
In accordance with another feature of the invention, in this case, the welded intermediate metal layer may be manufactured as a spiked metal sheet, in which passages are produced in the intermediate layer and even outside the overlap region using any desired methods such as e.g. punching or needling. Preferably, the passages are produced by needling from both sides of the metal foils.
In accordance with a further feature of the invention, first the welding of the metal foils and then the creation of the passages is effected. In general, however, a reversal of the process steps is also conceivable.
In accordance with an added feature of the invention, the thicknesses of the metal foils in the context of the present invention are preferably up to about 250 xcexcm, more preferably about 25 to 125 xcexcm and particularly preferably about 50 to 100 xcexcm.
Metal foils, which are used in the context of the present invention, are preferably made of nickel or iron materials.
It is particularly preferable if they are made of steel, nickel, Ni-based alloys or special steels such as chrome nickel steels.
In accordance with an additional feature of the invention, the web width of the metal foils, which are welded together, is preferably xe2x89xa7300 mm. They may, however, also have any other desired width. Two or more metal foils or metal layers may be welded together simultaneously or in succession.
The intermediate metal layers in the context of the present invention are preferably smooth metal foils or spiked metal sheet. A spiked metal sheet has numerous passages, which are produced by needling from one or both sides of the metal foils and are preferably uniformly distributed over the entire surface. These passages preferably have crown-shaped continuations which extend out and away from the surface of the metal foils. These crown-shaped continuations are used to secure further layers, e.g. soft material foils, mechanically by enmeshing. Preferably, needles having a square or round cross section are used. The passages then also have a square or round shape.
In accordance with yet another feature of the invention, in the context of the present invention, the intermediate metal layers are joined to at least one layer of soft material. The metal-reinforced layered composites according to the invention preferably include at least two layers of soft material, in which at least one intermediate metal layer is embedded. In an advantageous manner, the soft materials are applied onto the intermediate metal layers in the form of soft material layers, which preferably completely cover both sides of the intermediate metal layers. This may include e.g. the following configurations: soft material layer/intermediate metal layer/soft material layer or soft material layer/intermediate metal layer/soft material layer/intermediate metal layer/soft material layer.
In the context of the present invention, the soft materials are soft, adaptable, gas-proof, to some extent flexible materials which apply themselves particularly in a sealing manner against the surface of the metal foils and weld seams. The soft materials are, for example, expanded graphite, mica and polytetrafluoroethylene (PTFE). One or several different soft materials may be used in a metal-reinforced layered composite according to the invention.
In accordance with yet a further feature of the invention, the soft materials are preferably used in the context of the present invention in the form of soft material foils or laminates. These foils preferably have a thickness of about 0.2 to 2.0 mm, particularly preferably about 0.5 to 1.0 mm.
In accordance with yet an added feature of the invention, foils of expanded graphite which have a density of about 0.7 to 1.4 g/cm3 are particularly preferably used. Foils of expanded graphite have a high temperature stability and media resistance.
In accordance with yet an additional feature of the invention, the metal-reinforced layered composites are preferably used as gasket sheets. Gaskets of any desired shape may be manufactured e.g. by being punched out of the layered composites or gasket sheets according to the invention. Such gaskets may be flat gaskets, preferably annular flange gaskets or annular stuffing box packings.
Gaskets made from the layered composites according to the invention are used, for example, in the chemical industry, in power stations and in vehicle construction, e.g. as cylinder head gaskets and stuffing box packings for the purpose of sealing spindles.
The present invention has, inter alia, the following advantages:
Gaskets manufactured from the metal-reinforced layered composites according to the invention, with the welding together of the metal foils in the layered composites being effected in accordance with the geometric dimensions of the gaskets, have at least no continuous leakage channels at least in the region of the weld seam of the intermediate metal layers. They therefore have low leakage rates similar or identical to gaskets manufactured from layered composites, which have single-piece metal foils, i.e. metal foils without imperfections. Reference is also made, in that regard, to the examples and comparative examples.
The fact that the metal-reinforced layered composites according to the invention may be manufactured in large sizes means that there is less punching of waste when manufacturing gaskets. There is moreover the possibility of producing larger gaskets, e.g. annular flat gaskets having an outside diameter greater than 1 m, which are not inferior in quality to the previously known gaskets manufactured from layered composites with single-piece intermediate metal layers.
The present invention may also help to save material costs because metal foil webs having a lower width may be less expensive to purchase or more easily available than metal foil webs with greater widths.
With the objects of the invention in view there is additionally provided, a metal layer, comprising at least two at least partially overlapping metal foils which are joined to one another in an overlap region by at least one weld seam, wherein at the at least one weld seam in the overlap region between the metal foils there are no open regions and/or no continuous open regions in the longitudinal extent of the overlap region which, upon application thereof in metal foils in a layered material, act as leakage channels in the longitudinal extent of the overlap region. These metal foils may, in accordance with the welded intermediate metal layers of the metal-reinforced layered composites according to the invention, include welded metal foils and have corresponding passages. The inventive use of the metal layers relates to the use for manufacturing metal-reinforced layered composites, gasket sheets, gaskets and in particular flat gaskets made of at least one soft material.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a layered composite with a welded intermediate metal layer, a gasket, a gasket sheet, a metal layer and a method of manufacturing a layered composite, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

Layered composite with welded intermediate metal layer, gasket, gasket sheet, metal layer and method of manufacturing a layered composite


A ring protector for preventing unauthorized access through the dome port openings of a railcar dome. The ring protector defines a plurality of approximately equally spaced holes. The ring protector has an opened position in which each of the dome port openings is in-line with one of the access holes and a closed position in which each of the port openings is not in-line with one of the access holes. The ring protector is adapted to be rotatable from the opened position to the closed position.

The present invention relates to a ring protector. More specifically, it relates to a ring protector for preventing tampering of valves positioned inside a railcar dome.
Valves and actuators for tanker railway cars are subject to severe limitations due to standards imposed by various governing bodies, such as the Chlorine Institute and the Association of American Railroads. For instance, a valve/actuator combination must be attachable to the industry standard manway cover which covers the openings in the tanker railcar. A standard railcar 10 having a manway cover 12 is illustrated in FIG. 1. The standard manway cover 12 provides for the attachments of four valves 14, including two valves for liquids and two valves for vapors. Furthermore, all four valves 14 must fit within the confines of a dome 16 covering the manway cover 12. While the prior art dome illustrated in FIG. 1 has four valves, other prior art domes exist with three or five valves.
A sectional view of a standard dome 16 is illustrated in FIG. 2 and a top view of the standard dome 16 is illustrated in FIG. 3. The dome 16 covers and protects the valves 14 placed therein. The dome 16 includes a dome ring 18 surrounding the valves 14 and a convex dome lid 20 overlaying the dome ring 18. As seen in FIG. 3, a plurality of circumferentially and equally spaced bolts 22 attach the dome 16 to the manway cover 12. The dome ring 18 defines four approximately equally spaced dome port openings 24. The dome port openings 24 allow restricted access to the valves 14 positioned inside the dome 16 without removing the dome. The Association of American Railroads provides guidelines for the sizes of both the dome and the dome port openings. The actual sizes of the dome and the dome port openings are normally specified by the car builders based on the guidelines provided the Association of American Railroads.
While the dome port openings 24 provide the convenience of having access to the valves 14 without having to remove the dome 16, the dome port openings 24 also allow moisture to enter into the dome 16 and an unauthorized person to tamper with the valves 14. Such tampering of the valves 14 may release hazardous vapors, such as chlorine, into the atmosphere. To prevent moisture from entering the dome 16, one solution is to mount four rotatable circular plate 26 on the outer surface of the dome ring 18. Each plate 26 is mounted adjacent to a dome port opening 24 such that the plate 26 can be rotated to an opened position in which the plate 26 does not block the dome port opening 24. To prevent moisture from entering the dome 16 through the dome port opening 24, the plate 26 can be rotated to a closed position in which the plate 26 completely blocks the dome port opening 24 as illustrated in FIG. 4. While such prior art circular plates 26 can prevent moisture from entering the dome 16 through the dome port openings 24, the plates 26 cannot prevent an unauthorized person from tampering with the valves 14. Therefore, there exists a need for assuring that the dome port openings remain blocked when authorized access to the valves are not required.
FIG. 1 is a side view of a tanker railcar with a prior art dome attached;
FIG. 2 is a sectional view of the prior art dome of FIG. 1;
FIG. 3 is top view of the prior art dome of FIG. 1;
FIG. 4 is a prior art rotatable circular plate mounted to the outer surface of the dome to block the dome port opening;
FIG. 5 is a perspective view of a ring protector in accordance to the present invention for preventing unauthorized access through the dome port opening;
FIG. 6 is a top view of the ring protector of FIG. 5;
FIG. 7 is a side of the ring protector of FIG. 5;
FIG. 8 is a perspective view of the ring protector of FIG. 5 as situated within a dome;
FIG. 9 is a sectional view of a dome in accordance to the present invention with the ring protector of FIG. 5 situated in the opened position and the dome lid in the opened position;
FIG. 10 is a sectional view of the dome and ring protector of FIG. 9 with the ring protector sit the closed position and the dome lid in the opened position;
FIG. 11 is a sectional view of the dome and ring protector of FIG. 9 with the ring protector situated in the opened position and the dome lid pivoted toward the closed position;
FIG. 12 is a sectional view of the dome and ring protector of FIG. 9 with the ring protector situated in the closed position and the dome lid in the closed position;
FIG. 13 is a top view of a lid bracket in accordance to the present invention; and
FIG. 14 is a side view of the lid bracket of FIG. 13.

Ring protector for preventing tampering of valves positioned inside a railcar dome


A system and method for simultaneously accessing video data and Internet page data includes a format manager that inserts a video tag into page data to concurrently display a positionable video window and the page data upon the screen of a display device. The format manager reformats the displayed page data to avoid the video window when shown on the display device. The format manager also maintains the video window in a stationary position when a system user scrolls the page data in relation to the video window.

1. Field of the Invention
This invention relates generally to electronic systems that access and use information obtained from distributed computer networks, and relates more particularly to a system and method for simultaneously accessing video data and Internet page data.
2. Description of the Background Art
Efficient techniques for accessing and utilizing information are important considerations for manufacturers, designers and individual users of modern electronic information systems. Sources of such electronically-available information include various types of electronic networks, such as the Internet, which are typically accessible through a compatible computer device or other similar electronic system.
One significant contemporary technique for accessing information available on the Internet consists of a television set (for displaying information) and a "set-top box" device (for accessing selected information from the Internet and then providing the accessed information to the corresponding television set for display). As the foregoing name implies, a set-top box is typically a relatively small and economical device which is located near the television set to serve as an efficient interface with the Internet in consumer home-use applications.
A consumer television system that also accesses the Internet may therefore be used either in the normal television viewing mode, or may alternately be used to access and view selected Internet data pages ("web pages"). Since a live television broadcast may contain subject matter of immediate interest to a viewer, several methods for simultaneously accessing "live" video data and Internet data pages have been developed.
Referring now to FIG. 1A, a block diagram of a basic picture-in-picture system for displaying video data is shown. FIG. 1A includes a television 112 having a display screen 114 for displaying selected data. According to the picture-in-picture method for displaying multiple sources on screen 114, a first video source is displayed on screen 114, and a second video source is displayed on a smaller display area 116. Although two data sources are simultaneously displayed on television 112, the display area 116 covers a section of screen 114, and a viewer of television 112 is thus prevented from viewing images from the first video source which are obscured by superimposed display area 116.
Referring now to FIG. 1B, a block diagram of a basic split-screen system for displaying video data is shown. FIG. 1B includes a television 112 having a display screen 114 for displaying selected data. According to the split-screen method for displaying multiple sources on television 112, a first video source is displayed on a split-screen area 118, and a second video source is displayed on a split-screen area 120.
The screen 114 of television 112 has a fixed horizontal-versus-vertical aspect ratio, and consequently, data intended for display on television 112 is formatted to conform to the appropriate aspect ratio. Although two data sources are simultaneously displayed on television 112, the aspect ratios of both spit-screen area 118 and split-screen area 120 are significantly altered by employing the foregoing split-screen technique. A change in aspect ratio thus results in displayed images which are not correctly sized to conform to the size of spit-screen area 118 and split-screen area 120.
The foregoing problems result in either the loss of displayed information, or the inefficient use of space on screen 114. However, simultaneously accessing multiple sources of visual information, while avoiding the problems discussed above in conjunction with FIG. 1A and FIG. 1B, would clearly provide a powerful and effective system for utilizing various types of data. Therefore, for all the foregoing reasons, an improved system and method are needed for simultaneously accessing video data and Internet page data.

System and method for simultaneously accessing video data and internet page data


Disclosed herein is a vibration damper comprising 30-70 wt. % of a vibration damper base composed of approximately 30-38 wt. % of a resin component and approximately 55-65 wt. % of aromatic components and obtained either by adjusting the components contained in an asphalt base crude oil in the course of its refining or by blending and adjusting a resin component and aromatic component contained in petroleum asphalt, and 50-20 wt. % of an inorganic filler in the form of a thin flake of 20-200 mesh, the sum of said vibration damper base and filler being at least 80 wt. %. The vibration damper is suitable for installation on the floors of vehicles.

1) Field of the Invention
This invention relates to a vibration damper for damping the propagation of vibration through solid, which is caused by the vibration of steel panel sheets for vehicles such as cars, covers for machines, etc., and especially, to a vibration damper suitable for use in installing on the floors of vehicles.
2) Description of the Related Art
Vibration dampers of this kind have heretofore been formed of a sheet obtained by mixing an inorganic filler and reinforcing fibers into a base comprising a conventional asphalt, for example, single blown asphalt or straight asphalt, or a mixed asphalt thereof, and a modifier such as a synthetic rubber or an elastomer, which is mixed therewith, said sheet having a high specific gravity.
Such vibration dampers exhibit excellent vibration-damping effect at low temperatures. However, such vibration-damping effect becomes lower as the temperature rises.
Thus, when the temperature of a location wherein the vibration damper is utilized is 40.degree. C. or higher at the time a vehicle is used, the vibration-damping effect is lowered.
For this reason, it is preferable that the vibration damper should be made thicker in order to enhance its vibration-damping properties. However, such a thicker vibration damper is not preferred because the weight of the vehicle is increased when it is installed on the floor of the vehicle. In addition, difficulties are also encountered with regard to the installation work. Accordingly, there is a limit even to the thickening of the vibration damper. This limit has involved a disadvantage in that it is impossible to sufficiently enhance the vibration-damping effect at 20.degree.-60.degree. C.
In addition, it has been known to incorporate a large amount of a filler in a vibration damper of this kind so as to improve its vibration-damping properties. This has been accompanied by a disadvantage that when such a vibration damper is installed on a vehicle floor made of a steel sheet, its adhesion properties to the steel sheet is deteriorated and reliable laying is hence infeasible unless an adhesive is used.

Vibration damper obtained by adjusting the resin and aromatic components of the asphalt base


The present invention is directed to a pressure-responsive valve assembly which functions in the nature of a check valve to control fluid flow across the assembly. The assembly includes a valve body which defines first and second internal flow passages, and includes a valve seat through which at least one flow port extends for joining the first and second passages in fluid communication with each other. A flexible, resiliently deformable valve member is positioned in operative association with the valve seat, and can be deflected, in response to a sufficient pressure differential, to move out of sealing engagement with the valve seat, to thereby permit fluid flow through the valve assembly. In the preferred embodiment, the valve seat of the valve assembly defines a compound sealing surface, including first and second sealing surfaces, which cooperate with the deflectable valve member to provide enhanced resistance to reverse fluid flow, with one preferred form of the present valve assembly further including a retention projection which cooperates with the valve member to further enhance resistance to reverse fluid flow.

There are many applications in which an economical and reliable mechanism for pressure-responsive fluid flow control can be advantageously employed. Such applications can include an interface between two fluid conduits or the like, wherein pressure-responsive introduction of a fluid from one conduit to the other is desired, while reverse fluid flow is prevented. Similar flow control requirements may exist in connection with typical dispensing applications, such as dispensing of consumer products such as beverages, or other flowable products. Many industrial applications require pressure-responsive fluid flow control with a check valve arrangement, again with it typically being necessary for reverse fluid flow to be minimized or substantially prevented.
One type of valve assembly for controlling fluid flow which has proven to be particularly cost-effective includes a deflectable, elastomeric valve member which is mounted within, and generally cooperates with, an associated valve body, which arrangement can be readily configured for pressure-responsive fluid flow control. U.S. Pat. Nos. 5,033,655, No. 5,213,236, No. 5,271,571, and No. 6,749,092, all of which are hereby incorporated by reference, illustrate such valve assemblies with these patents, disclosing various applications in which such valve assemblies can be advantageously employed.
The present invention relates generally to a valve assembly of the above-described type, which assembly can be configured for pressure-responsive operation in the nature of a check valve. In one particularly preferred embodiment, the present valve assembly is configured to permit pressure-responsive fluid flow in response to a pressure differential across the valve assembly, with features of the present invention particularly configured to limit and control reverse fluid flow through the valve assembly in response to a reverse pressure differential across the valve assembly.


A display device includes: a first wireless communication unit which performs wireless communication in a first format with an external device; a storage unit which stores connection information used in the wireless communication in the first format; a change unit which changes the connection information stored in the storage unit; and a display unit which displays an image received via the first wireless communication unit from the external device. A first information processing device includes: a wireless reader/writer which performs wireless communication in a second format in order to read information from or write information in a wireless tag; an acquisition unit which acquires the changed connection information; and a writing unit which outputs, to the wireless reader/writer, a signal for writing the connection information acquired by the acquisition unit into a first wireless tag.

1. Technical Field
The present invention relates to an information processing system and a display device.
2. Related Art
A technique of connecting an information processing device such as a smartphone or table terminal to a display device such as a projector via a wireless LAN (local area network) is known. Also, a technique of using near field communication (NFC) to establish wireless LAN connection is known. For example, JP-T-2012-502554 discloses a technique in which a mobile communication device detects NFC transmission and thereby detects the existence of a wireless LAN, thus facilitating the connection to the wireless LAN.
The technique disclosed in JP-T-2012-502554 has a problem that it is difficult to share connection information of the display device if the connection information is changed.

Information processing system and display device


The present disclosure discloses an agitator truck, and the agitator truck includes a frame; a first axle assembly; a second axle assembly, where the second axle assembly and the first axle assembly are disposed along a front-rear direction in a spaced manner, the second axle assembly includes two vehicle axle assemblies that are disposed along the front-rear direction in a spaced manner, each of the vehicle axle assemblies includes an axle case assembly, the axle case assembly includes an axle case component and two half axles, and the two half axles are located inside the axle case component; at least one of the two vehicle axle assemblies is an electric drive axle assembly, the electric drive axle assembly further includes an electric power assembly, the electric power assembly includes a power motor, a transmission, and a differential, the transmission has a transmission case, the power motor is fixed to the transmission case, the differential is supported on the transmission case, the differential is located inside the axle case component, and the transmission case is fixed onto the axle case component; and a suspension system, where each of the vehicle axle assemblies is connected to the frame through the suspension system. The agitator trunk according to the present disclosure high has a compact structure and integration degree and is environmental friendly.

In the related art, a power motor, a transmission, a transmission shaft, and a vehicle axle are all disposed separately, and power is transmitted stage by stage, resulting in a lot of transmission sections, a long transmission link, low transmission efficiency, a large volume, and difficult arrangement. In particular, with regard to some agitator trucks, in order to satisfy requirements for high power, volumes of power motors and transmissions are usually relatively large, axles withstand large torque, and it is difficult to ensure connection strength between vehicle axles and transmissions. Therefore, there is room for improvement.