A remote switching system for electrical switches in a cabinet provides simplified manufacture by attaching the flexible cable sheath and flexible cable to an actuator frame and slider, respectively, by means of flange elements attached to each of the sheath and cable that fit within corresponding receiving slots in the actuator frame and contained slider. A cover, which may be attached without fasteners, may then hold these flange elements within corresponding slots.

The present invention relates to high-power electrical switches, and in particular to a flexible cable assembly for remotely actuating electrical switches such as circuit breakers.
High-power electrical circuitry is normally placed inside a metal cabinet to protect the electrical circuitry from the external environment and to shield users from potential hazards associated with the operation of the circuitry.
Often the cabinet provides a handle that serves both to lock a cabinet door and to disconnect electrical power from the interior circuitry before the door is opened. The handle may communicate through a flexible cable assembly with a switch inside the cabinet, for example, a circuit breaker, so that when the handle is moved to allow opening of the cabinet door, the circuit breaker is also opened, removing electrical power from the interior circuitry. This feature is normally subject to the mechanical override in the event that the cabinet must be operated with the door open and the circuitry live.
A flexible cable assembly provides a substantially incompressible sheath through which a flexible cable may slide. Opposite ends of the sheath are fixed, respectively, to a stationary structure of the handle and an actuator frame attached to the circuit breaker housing. One end of the flexible cable is then attached to a movable portion of the handle to communicate this motion through the flexible cable to a slider held within the actuator frame. The slider may provide a collar capturing a toggle operator of the circuit breaker to move the circuit breaker toggle between an "on" and "off" position with movement of the flexible cable by the handle.
The end of the flexible cable of the flexible cable assembly may attached to the slider by means of a pair of opposed jam nuts attached to a threaded ferrule on one end of the flexible cable. The jam nuts are tightened against either side of a hole in the flange on the slider. Likewise, the sheath of the flexible cable assembly may be attached to the actuator frame by means of a pair of opposed jam nuts also tighten on opposite sides of a hole through a flange on the actuator frame. In both cases, the jam nuts serve the dual purpose of attaching the cable or the sheaf to corresponding structure and allowing adjustment of the relative points of attachment for "tuning" the remote actuation system.
"Tuning" adjusts the separation of the points of attachment of the flexible cable and the sheath to corresponding structure of the actuator and slide so that a given range of motion of the handle is translated to positions of the toggle operator of the circuit breaker sufficient fully switch the circuit breaker between its "on" and "oft" positions.
Assembly of the jam nuts to the respective attachment points of the slider and/or attachment frame requires that one jam nut be removed so that the threaded shaft holding the jam nuts can be inserted through the hole in the flange. The removed jam nut is then reinstalled and the two jam nuts adjusted for proper positioning. This process is cumbersome and time-consuming but allows the necessary tuning.
This latter step of tightening the jam nuts can also be difficult requiring that the actuator frame be partially disassembled and that the person making the assembly work within the close confines of that framework to loosen and tighten these two nuts. Once the two jam nuts are properly positioned they must be tightened together using torque-controlled tools to ensure that the connection does not inadvertently loosen during vibration or use and to ensure that the torque is not so high as to damage the threaded barrel on the end of the sheath causing the sheath to separate from the actuator.
After moving the jam nuts, it can be difficult to determine whether the adjustment is correct because the handle may not be operated with the jam nuts loose such as would allow the sheath to move freely. Accordingly multiple trials may be required for proper adjustment.
The slider and adapter assembly may be formed of folded metal to provide the necessary mounting flanges needed for the jam nuts. These metal parts must be lubricated to prevent seizing of the sliding operation between few contact surfaces of the slider and the actuator frame. While these metal components are robust they are electrical conductors and must be used with care in the vicinity of electrical circuitry and with consideration of conduction from the actuator through the flexible cable to the handle and the cabinet.

Flexible cable assembly with improved manufacturability


A method of supporting communication of a terminal in a first base station of a beamforming system is provided. The method includes determining an uplink control channel through which both the first base station and at least one second base station are able to receive signals, through cooperation with the at least one second base station, the first base station and the at least one second base station belonging to a cloud cell, and transmitting to the terminal information on the determined uplink control channel and frame information to establish relationships with the base stations included in the cloud cell for each transmit frame of a signal to be transmitted to the terminal from the base stations.

Communication systems have been developed to support higher data rate to meet the need for steadily increasing wireless data traffic. For example, fourth generation wireless communication systems has sought to develop technologies toward improving spectral efficiency to increase data rate.
Since such technologies are not enough to meet the need for soaring wireless data traffic, communication systems have been developed to secure a new frequency band. For example, since a wide frequency band is hardly secured below 10 GHz, communication at higher frequencies than 10 GHz is drawing attention as a future communication technology. However, the higher the transmission frequency for wireless communication, the shorter the propagation range, thus causing reduction of service coverage.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.

Coordinated communication in communication system


A motorcycle footrest used in combination with a motorcycle crash bar has a body member and a step member pivotally attached to the body member. The body member is disposed between adjacent portions of the crash bar. The footrest folds into the crash bar to provide a stream lined and custom appearance.

The present invention generally relates to motorcycle accessories and more specifically to devices for a motorcycle rider to place and rest his or her feet while riding the motorcycle.
A variety of different footrests and foot-pegs are known for supporting the feet of a motorcycle rider. In particular, different devices are known for a rider to rest their feet during long extended riding, when it is not necessary for the rider to have their feet in immediate proximity to a foot brake pedal or a foot operated gear shifter. With this type of footrest, the rider is able to elevate their feet and assume more of a reclined position. One variety of this type of footrest mounts on a device referred to as an engine guard, also referred to as a "crash bar". An example of a crash bar appears in U.S. Pat. No. 6,419,039 (Wagner). The known footrests which attach to a crash bar typically employ an attachment clamp to secure the footrest to the crash bar. However, these footrests may detract from the streamlined look that many motorcycle owners desire to achieve for their bike. In addition, if the clamp becomes loose, it can either rotate or slide upon the crash bar, providing a less than secure footrest.
The apparatus disclosed herein addresses these problems. The disclosed footrests may be included as an integral part of a newly purchased crash bar. Alternatively, the disclosed footrests may be purchased separately, and an existing crash bar modified to accept the footrests.


A video signal outputting apparatus includes an A/D converter, and video signals Y1-1 and Y3-1 outputted from the A/D converter are written into areas C1 and C3 of a VRAM, and therefore, images according to the video signals are displayed on a monitor. Then, video signals Y1-2 and Y3-2 are outputted from the A/D converter, and written into an area C5 of a further VRAM and the area C1 of the VRAM, respectively. Images according to the video signals Y1-2 and Y3-1 are displayed on the monitor at a timing that writing of the video signal Y1-2 is finished, and images according to the video signals Y1-2 and Y3-2 are displayed at a timing that writing of the video signal Y3-2 is finished.

1. Field of the Invention
The present invention relates to an image or video signal outputting apparatus. More specifically, the present invention relates to a video signal outputting apparatus which outputs N kinds of video signals to N of display means, respectively, like a time laps VCR.
2. Description of the Prior Art
One example of conventional such a kind of video signal outputting apparatus 1 applied for a time lapse VCR which outputs 4 kinds of video signals from a monitor by dividing a screen into 4 blocks is shown in FIG. 38. In this video signal outputting apparatus 1, video signals Y1 and Y3 outputted from an A/D converter 2a are written into a VRAM 4a in response to a write control signal from a microcomputer 3, and video signals Y2 and Y4 outputted from an A/D converter 2b are written into a VRAM 4b by the write control signal from the microcomputer 3. More specifically, the video signals Y1 and Y3 are written into areas A1 and A3 of the VRAM 4a shown in FIG. 39, respectively, and the video signals Y2 and Y4 are written into areas A2 and A4 of the VRAM 4b, respectively. Then, addresses of the VRAM 4a and 4b are scanned downward as shown in FIG. 40 such that the video signals Y1 to Y4 are read-out and outputted through a multiplexer 5 and a D/A converter 6. Therefore, images according to the video signal Y1 to Y4 are displayed on a monitor 7 as shown in FIG. 41.
Furthermore, in another example of conventional such a kind of video signal outputting apparatus 1 as shown in FIG. 42, video signals Y1 to Y4 outputted from an A/D converter 2a are sequentially written into areas A1 to A4 of VRAMs 4a and 4b, and video signals Y1 to Y4 outputted from an A/D converter 2b are sequentially written into areas B1 to B4 of VRAMs 4c and 4d. Since a microcomputer 3 switches write signals for the VRAMs 4a and 4b and write signals for the VRAMs 4c and 4d at every one field, video signals Y1-1 to Y4-1 outputted at a last time are written into the VRAMs 4a and 4b, and video signals Y1-2 to Y4-2 outputted at a present time are written into the VRAMs 4c and 4d, as shown in FIG. 43(B). Furthermore, a video signal Y1-3 outputted at a next time from the A/D converter 2a is written into the area A1 as shown in FIG. 43(C).
Thus, a newest video signal out of the video signals written into the VRAMs 4a to 4d is applied to a monitor 7. Accordingly, when the video signals are stored in the VRAMs 4a to 4d as shown in FIG. 43(B), images according to the video signals Y1-2 to Y4-2 in the VRAMs 4c and 4d are displayed on the monitor 7 as shown in FIG. 44(A). Then, during a time that an video signal Y1-3 is being written as shown in FIG. 43(C), the images shown in FIG. 44(A) are displayed on the monitor 7, and when writing of the video signal Y1-3 is completed, images according to the video signals Y1-3, Y2-2, Y3-2 and Y4-2 are displayed as shown in FIG. 44(B).
However, in the prior art shown in FIG. 38, a writing speed and a reading speed of the video signal are different from each other as shown in FIG. 45. Accordingly, in a case where reading is started while the video signal Y3-2 is being written in the area A3 as shown in, for example, FIG. 46, the last video signal Y3-1 and the present video signal Y3-2 are outputted on the monitor 7 as shown in FIG. 47, and therefore, there was a problem that the images are incoincident with each other at an upper side and a lower side of the monitor.
Further more, in the prior art shown in FIG. 42, though the problem that the images are incoincident with each other at the upper side and the lower side is solved, VRAMs twice the prior art shown in FIG. 38 are needed, and therefore, there was a problem that the number of parts increases and a cost becomes high.


An improved wheelbarrow in a disassembled condition is disposed in a carton that conforms substantially with the orthogonal dimensions of a tray of the wheelbarrow. The other components of the wheelbarrow comprise a frame subassembly, a pair of handle members, a wheel, an axle, and a number of fasteners, and these other components are disposed substantially entirely within an interior of the tray within the carton, such as during shipping and storage. The wheelbarrow is assembled by removing the wheelbarrow components from the carton, pivoting a pair of riser members of the frame subassembly with respect to a frame member of the frame subassembly, and attaching the pair of handle members to the frame member and to the riser members. The tray and the wheel are mounted to the riser members.

1. Field of the Invention
The present invention relates generally to wheelbarrows and, more particularly to an apparatus and method wherein a disassembled wheelbarrow is provided in a relatively small package and is easily assembled.
2. Description of the Related Art
Numerous wheelbarrows of numerous different configurations are known. One fact that is particularly acknowledged is that wheelbarrows are generally large and bulky. Such bulkiness is due, at least in part, to factors such as the need for a tray that will carry a sufficiently large payload, the need for a frame that rollably supports the tray on a grade, and one or more handles that are spaced from the tray and that can be held by a user. As a result, the components of a wheelbarrow occupy a significant space, even when in an unassembled condition.
There can be no doubt that the disassembled components of an article, such as a wheelbarrow, can be packaged in a small container depending upon how small one chooses to make each of the individual components. Small components typically are assembled to form a small structure unless many small components are provided and are assembled to form a relatively larger structure. The assembly of an object out of a relatively greater number of components will often be relatively more complex than the assembly of a similar object made up of fewer components. It is also understood that a given structure often is stronger as a unitary member than when formed out of many smaller pieces connected together, such as in the way a single beam would generally be stronger than a similarly sized structure assembled out of numerous components.
For the most part, therefore, the different goals of ease of assembly, strength, and minimized packaged size would appear to mutually compete with one another. A need thus exists for a strong wheelbarrow that has a relatively small packaged profile yet is easy to assemble, along with an associated method.
Small packaging of a disassembled wheelbarrow is highly desirable since disassembled wheelbarrows often occupy two separate cartons. One carton includes the relatively longer components such as frame and handle pieces, and a separate carton carries a wheelbarrow tray and other components. Such packaging of a disassembled wheelbarrow in multiple cartons is undesirable since a consumer must correctly pick both of the cartons, often from among other cartons associated with other wheelbarrows, and must carry the two cartons to a checkout counter. This is cumbersome and subject to an incorrect selection of one of the packages by the consumer. A need thus also exists for a wheelbarrow that is strong, easy to assemble, and is packaged within a single container when in a disassembled condition.

Packaged wheelbarrow and associated method


A medical electrode is made up of an insulating adhesive layer and an electrically conducting contact layer secured in a frictionally abutting relationship on an electrical terminal such that the contact layer is independently rotatable about the terminal. The contact layer provides an electrically conductive surface enabled for establishing common potential simultaneously with at least one removable electrode and the terminal. The terminal provides a base portion positioned for electrical contact with a skin surface when the adhesive layer is adhered to the skin surface.

1. Field of the Present Disclosure
This disclosure relates generally to medical devices and more particularly to a medical electrode with plural connection points for attachment of several monitoring devices simultaneously.
2. Description of Related Art Including Information Disclosed under 37 CFR 1.97 and 1.98
Medical electrodes are utilized in a number of applications for a variety of diagnostic and monitoring purposes. For instance, electrodes commonly are used to monitor physiological electric potentials to detect muscular activity of a person's heart. The cardiovascular activity of the heart is typically monitored by adhering or connecting electrodes to the skin of the patient at particular locations of interest on the body. The electrodes are then electrically coupled to electrical equipment such as an electrocardiograph (also referred to as EKG) apparatus that monitors the muscular activity of the heart. The resulting traces or output of the EKG provides a diagnostic tool for detecting heart disease and/or heart dysfunction of various etiology.
Applicant's prior patent, U.S. Pat. No. 5,626,135 describes the uses of medical electrodes and applications in the prior art quite thoroughly. U.S. Pat. No. 5,626,135 is hereby incorporated into the present application by reference.
LeSourd, U.S. Pat. No. 7,164,939 extends the concept of U.S. Pat. No. 5,626,135 to the usage of plural tabs.
The prior art does not teach the construction of a medical electrode with plural tabs wherein the electrode with tabs is able to be rotated to provide the ability to attach clip- on wires in a more convenient manner that may be advantageous in preventing wire tangles.


A machine vision system for substrate alignment includes first and second illumination sources (11, 12), first and second reflectors (21, 22), first and second objective lenses (31, 32) and first and second detectors (41, 42), each of which pair is symmetric with respect to an X-axis. Light beams emitted from the first and second illumination sources are irradiated on and reflected by respective substrates (1, 2), amplified by the respective objective lenses and received and detected by the respective detectors. An alignment apparatus is also disclosed. Disposing each of the pair of the first and second illumination sources, the first and second reflectors, the first and second objective lenses and the first and second detectors in symmetry with respect to the X-axis results in a significantly reduced footprint of the machine vision system along the orientation of lens barrels of the objective lenses and hence an expanded detection range thereof and improved alignment efficiency and accuracy.

In a traditional semiconductor process, before two substrates are bonded together, they must be aligned with each other using a substrate bonding apparatus. Substrate alignment is one of the most important techniques involved in substrate bonding.
In an existing substrate alignment method, two substrates to be bonded are first positioned with their respective mark-bearing surfaces facing toward each other, and two sets of microscope objective lenses then detect the positions of the two groups of alignment marks, followed by elimination of an offset therebetween by actuators. Limited to the bonding process, the alignment must be conducted with a spacer inserted between the two substrates for ensuring non-contact between the two substrates prior to the bonding. This creates a rather large gap between the two substrates, and the gap is usually greater than 0.4 mm. Depths of field of the used microscope objective lenses are required to exceed the distance between the two substrates in order to obtain clear images of the alignment marks on the two substrates. However, for any microscope objective lens, there is a tradeoff between its resolution and depth of field. That is, a microscope objective lens with a greater depth of field typically has a lower resolution. For this reason, it is difficult to further increase alignment accuracy by adopting higher-resolution microscope objective lenses due to the depth-of-field constraint.
In order to overcome this problem, there has been proposed an inspection device in the prior art, as shown in FIG. 1, which includes a machine vision system having two pairs of microscope objective lenses 3′ both arranged between a first substrate 1′ and a second substrate 2′ in order to respectively detect alignment marks on the first and second substrates 1′, 2′ and aligns the first and second substrates 1′, 2′ by six-degree-of-freedom (6-DOF) movement of motion stages supporting the respective substrates based on the detection results of the objective lenses. In this approach, in order to focus on the first and second substrates 1′, 2′ and search for the alignment marks, the microscope objective lenses 3′ of the machine vision system are required to be movable in all the X, Y and Z directions, but since the microscope objective lenses 3′ of the machine vision system are coaxially oriented horizontally, their bulky lens barrels take up much of the space between the substrates, resulting in a limited detection range of the machine vision system in this direction. As a result, some areas of the substrates are not accessible for the machine vision system, limiting its overall alignment accuracy.

Machine vision system for substrate alignment and alignment device

Shanghai Micro Electronics Equipment (Group) Co., Ltd.


A protection assembly for connectors is included on a circuit pack to prevent damage caused when a connector is removed while signal power is still being supplied to the circuit pack. More specifically, the protection assembly is disposed on the front side of the circuit pack to prevent access to the connector until signal power is automatically cut off from the circuit pack. In one embodiment, the circuit pack is the type having a lever arrangement capable of causing the circuit pack to engage and disengage the backplane of an equipment frame. When the circuit pack is engaged in the backplane, signal power is supplied through the connector that is accessible, for example, on the face plate of the circuit pack. The protection assembly includes a first shield member mounted on the face plate of the circuit pack in a location adjacent to the connector. The protection assembly further includes a second shield member mounted or otherwise formed on the lever arrangement. When the circuit pack is engaged in the backplane, the first and second shield members cooperate to prevent access to the connector protected thereunder. To expose the connector, a technician would have to operate the lever arrangement to separate the first and second shield members. Because the circuit pack is disengaged from the backplane by action of the lever arrangement, signal power supplied to the connector is therefore automatically cut off before the first and second shield members are separated to expose the connector.

Circuit packs used in lightwave communication systems may include optical fiber connections to facilitate the transport of optical signals. For example, an optical fiber carrying an optical signal supplied from a component on a circuit pack may be connected to another optical fiber that transports the optical signal to another circuit pack. In one common arrangement, a connector sleeve is provided on the face plate of the circuit pack to receive connectors on the ends of each of the optical fibers. When the circuit pack is engaged in the backplane of an equipment shelf and receiving power, optical signal power is supplied through the optical fibers and the associated connectors.
The connector sleeve is typically incorporated on the face plate in order to provide easy access for operational and maintenance functions. However, this accessibility can create problems if a technician attempts to remove a connector from the connector sleeve while optical signal power is still being supplied through the optical fibers and associated connectors. For example, the power level of an optical signal may be sufficiently high to cause damage to the fiber core in a connector. As a result, maintenance costs as well as operational downtime may increase while the optical fibers, connectors, or entire circuit pack are being repaired or replaced. Even if the damage does not warrant immediate repair, damaged components may cause other operational problems, such as higher insertion loss for the circuit pack.
Recent developments in optical networking will only increase the likelihood of these types of problems. For example, optical amplifiers and other optical components are now being developed to drive optical signals to even higher output power levels. Multi-wavelength systems are also a concern because total optical power in the optical fiber is the sum of the powers of the individual wavelength components. As the number of wavelength components increases, e.g., from present systems of 16 wavelengths to future systems of 80, 96, and so on, the total output power of optical systems will also increase accordingly. As a result, the potential for damage to optical connectors and other optical components will also increase.
Given the output power levels of current and next generation systems, existing arrangements do not provide adequate protection against damage to connectors and the like. For example, most existing arrangements are based on a manual process in which a technician performs several steps locally at the circuit pack or remotely at a terminal to manually cut off power before removing a connector. Because the connector is exposed and unprotected on the face plate of the circuit pack, the only safeguard for ensuring that a technician does not prematurely remove the connector is typically a warning label placed on the equipment alerting the technician to perform the required steps before removing the connector. Among other obvious shortcomings, this type of arrangement is especially prone to human error, e.g., if a technician fails to shut off power for any number of reasons before removing a connector.
Other known equipment protection arrangements include latch and switch mechanisms that interact to interrupt electrical power during insertion and removal of a circuit board. However, these arrangements do not protect against damage to connectors that are accessible on the face plate of a circuit pack.

Apparatus for protecting connectors on circuit packs


A satellite communication system is disclosed which provides at least one satellite employing multiple beams to a plurality of user terminals. A gateway is employed to connect to either a PSTN or an Internet communicating with the user terminal over the constellation so that the users within a given frequency range are distinguished one from the other employing orthogonal codes. The user terminal has the capability of either initiating or receiving packet data messages.

Historically, the telephone, which comes from the Greek word 'tele', meaning from afar, and 'phone', meaning voice or voice sound, is said to have been invented on Mar. 10, 1876 in Boston, Mass. by Alexander Graham Bell. The principle of the telephone was conceived as early as 1874 combining electricity and voice which led to Bell's actual invention of the telephone in 1876.
U.S. Pat. No. 174,465 issued Mar. 3, 1876 for improvements in telegraphy is now considered to be the most valuable patent ever issued.
Telstar, the world's first international communications satellite, years later was placed into orbit on Jul. 10, 1962 in a collaboration between NASA and the Bell System. Today satellites in geosynchronous orbit are used mostly for long distance service.
The basic concept of cellular phones which began in 1947 with crude mobile car phones resulted in the realization that using small cells or range of service area with frequency re-use could increase the traffic capacity of mobile phones substantially. However, at this point in time the technology was nonexistent. The cellular telephone is in fact a type of two-way radio which in 1947 AT&T proposed at the FCC allocated large number of radio spectrum frequencies so that widespread mobile phone service could become feasible and provide AT&T an incentive to research the new technology. The FCC's decision to limit the cellular phone frequencies in 1947 resulted in the possibility of only 23 cellular phone conversations which could occur simultaneously in the same service area. In 1968 this was increased. Thereafter, a cellular phone system was proposed by Bell Laboratories. In 1977 AT&T Bell Labs constructed and operated a prototype cellular phone system. In 1981 Motorola and America Radio Phone started a second U.S. cellular radio phone system test in the Washington/Baltimore area. Suddenly consumer demand quickly outstripped the cellular phone system's 1982 standards so that by 1987 cellular phone subscribers exceeded one million and the airwaves were crowded. To stimulate the growth of new cellular phone technology, the FCC declared in 1987 that cellular phone licenses may employ alternative cellular phone technologies in the 800 megahertz band.
Digital wireless and cellular find their roots back in the 1940s when commercial mobile telephony began. On Jun. 17, 1946 in St. Louis, Mo., AT&T and Southwestern Bell introduced the first American commercial mobile radio telephone service and mobile telephony a channel is a pair of frequencies, one frequency to transmit on and one to receive.
A cell phone is a portable telephone which receives or sends messages through a cell site or transmitting tower. Radio waves are used to transfer signals to and from the cell phone, each cell site having a range of 3-5 miles and overlapping other cell sites. All of the cell sites are connected to one or more cellular switching exchanges which can detect the strength of the signal received from the telephone. As the telephone user moves or roams from one cell area to another, the exchange automatically switches the call to the cell site with the strongest signal. The term 'cell phone' is uncommon outside the United States and Japan. However, almost all mobile phones use cellular technology including GSM, CDMA and the old analog mobile phone systems. Hence, the term 'cell phone' has been regarded by many to designate any mobile telephone system. An exception to mobile phones which employ cellular technology are satellite phones; for example, the Iridium phone system which is very much like a cell phone system except the cell sites are in orbit. Marine radio telephone satellites administered by Inmarsat have a completely different system. The Inmarsat satellite system simply retransmits whatever signals it receives with a mobile station's actually logging into a ground station.
With the advent of the Globalstar® satellite telephone system, a great advance in the art was recognized by virtue of a basic telephonic satellite technology which provided a constellation of 48 satellites in low earth orbit which were much simpler to build and less expensive than those of Iridium employing a radically different technology which employs code division multiple access, or CDMA, technology, converting speech signals into a digital format and then transmitting it from the Globalstar® satellite phone up to satellite systems and down to the ground station. Every call on the Globalstar® system possesses its own unique code which distinguishes it from the other calls sharing the airwaves at the same time, and employing CDMA provides signals which are free of interference, cross-talk or static. CDMA was introduced in 1995 and soon became the fastest growing wireless technology and one that was chosen by Globalstar® for use in its satellite communications network, which service Globalstar® launched in 2000.
The key features of the Globalstar® satellite phone employing CDMA provide unique forward and reverse links, direct sequence spread spectrum, seamless soft handoff, universal frequency re-use, propagation through multiple overlapping beams on multiple satellites for diversity, and variable rate transmission.
The Globalstar® satellite phone service is delivered through 48 low earth orbiting satellites providing both voice and data services. The so-called Globalstar® LEO constellation consists of satellites arranged in a Walker constellation, and each satellite is approximately 700 miles from the earth which allows for the highest quality voice clarity of any satellite phone in the industry. At the heart of the Globalstar® system as initially proposed is Qualcomm's adaptation of code division multiple access technology which provides Globalstar's® digital satellite service, resulting in a technology which provides signal security, superior quality, fewer dropped calls and greater reliability. Calls can be made from any gateway via any satellite of the system to any user terminal, as long as the satellite is co-visible from both gateway and user terminal. This co-visibility is what defines a gateway service area; at least 24 gateways around the globe are used to provide worldwide coverage. Each satellite serves at least 2,000 simultaneous users.
The Globalstar® system employs redundancy with every call that a customer places so that a call is routed through as many as four satellites which then combine the signal into a single static-free call. In the event that one of the paths to one of the satellites is blocked, the other satellites keep the call from terminating, applying the technology of path diversity which minimizes dropped calls and enhances the quality of the Globalstar® satellite phone service. The Globalstar® system employs bent pipe technology which allows a call to be first beamed up to the satellite and then retransmitted to a relatively close gateway. The call is then sent through its call destination through land line or cellular networks. The Globalstar® gateway carries out all the processing and switching of the calls which improves the reliability of the call delivery, unlike the Iridium system which requires satellite-to-satellite transmission.
In addition, the Globalstar® system, which provides reliable call delivery with voice characteristics the same or better than conventional telephony, complements the current cellular telephone systems in existence by allowing the user to first use conventional cellular, which is far less expensive but totally dependent upon the proximity of cell sites for its reliability, and then allows the user to select the Globalstar® satellite system where cell sites are far too distant to be reliable or in remote locations where these sites are non-existent. Code division multiple access, which refers to a multiple access scheme where stations use spread spectrum modulations and orthogonal codes to avoid interfering with one another, is typically employed in Globalstar® systems. The CDMA modulation technique is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communications system techniques such as time division multiple access (TDMA), frequency division multiple access (FDMA), and AM modulation schemes such as amplitude expanded single sideband (ACSSB) are known in the art. The spread spectrum modulation technique of CDMA is found to have significant advantages over these modulation techniques for multiple access communications systems. CDMA techniques in multiple access communications systems are disclosed in U.S. Pat. No. 4,901,307 entitled Spread Spectrum Multiple Access Communication System Using Satellite or Terrestrial Repeaters, the disclosure thereof is incorporated by reference.
In this patent, a multiple access technique is disclosed where a large number of mobile telephone system users each having a transceiver communicate through satellite repeaters or terrestrial base stations, also referred to as cell sites stations, cell sites, or for short cells, using code division multiple access (CDMA) spread spectrum communication signals. Frequency spectrum employed in CDMA can be reused multiple times, thus permitting an increase in system user capacity. The CDMA is found to result in a much higher spectral efficiency than can be achieved using other multiple access techniques.
Satellite channels employing this system typically experience fading that is characterized as Rician. Accordingly, this signal is found to consist of a direct component summed with a multiple reflected component having a Rayleigh fading statistic. A power ratio between the direct and reflected component is typically found to be on the order of 6 to 10 dBs depending upon the characteristics of the mobile unit antenna and the environment about the mobile unit. Contrasted to the satellite channel, the terrestrial channel experiences signal fading that typically consists of the Rayleigh faded component without a direct component. This terrestrial channel is found to present a more severe fading environment than the satellite channel in which the Rician fading is the dominant fading characteristic.
The Rayleigh fading characteristics experienced in the terrestrial signal is found to be caused by the signal being reflected from many different features of the physical environment, resulting in a signal which arrives at a mobile unit receiver from many directions with different transmission delays. In the UHF frequency bands which are usually employed for mobile radio communications, including cellular mobile telephone systems, there is found to be significant phase differences in signals traveling on different paths which provides the possibility of destructive summation of the signals causing occasional deep fades. Physical position of the mobile unit is a strong function of the terrestrial channel fading so that small changes in the position of the mobile unit change the physical delays of all the signal propagation paths which further result in a different phase for each path. The motion of the mobile unit through the environment can result in a rapid fading process; for example, employing 850 MHz cellular radio frequency band, the fading can typically be as fast as one fade per second per mile per hour of the vehicle speed. This level of fading is found to be extremely disruptive to signals in a terrestrial channel, resulting in poor communication quality. Quality may be improved by providing additional power to overcome the fading, which in itself affects both the user in excessive power consumption and the system by increased interference. Certain CDMA modulation techniques disclosed in U.S. Pat. No. 4,901,307 offer some advantages over narrow band modulation techniques using communication systems employing satellite or terrestrial repeaters. The terrestrial channel is found to pose special problems to any communication system, particularly with respect to multiple path. These problems may be overcome by using CDMA techniques which overcome the special problems of the terrestrial channel by mitigating the adverse effect of multipath, for example fading, while also exploiting the advantages of multipath.
CDMA cellular telephone systems allow the same frequency band to be employed for communication in all calls. CDMA waveform properties that provide processing gain are also used to discriminate between signals that occupy the same frequency band. Furthermore, the high speed pseudo-noise PN modulation allows many different propagation paths to be separated provided the difference in path delay exceed the PN chip duration; i.e., 1/bandwidth. It is found that if a PN chip rate of approximately one MHz is employed in a CDM system, the full spread spectrum processing gain equal to the ratio of the spread bandwidth to system data rate can be employed against paths that differ by more than one microsecond in path delay from desired path. It is found that a one microsecond path delay differential corresponds to differential path distance of approximately 1,000 feet, the urban environment typically providing differential path delays in excess of one microsecond and up to 10-20 microseconds in some areas. When narrow band modulation systems are employed, such as at analog FM modulation, by conventional telephone systems, the existence of multiple paths results in severe multipath fading. By employing wideband CDMA modulation, the different paths may be discriminated against in the demodulation process which greatly reduces the severity of multipath fading. Although multipath fading is not totally eliminated using CDMA discrimination techniques, there will occasionally exist paths with delayed differentials of less than the PN chip duration for the particular system. For signals which possess path delays on this order, it is found that signals cannot be discriminated against in the demodulator, resulting in some degree of fading.
It becomes apparent that some form of diversity is desirable which would permit a system to reduce fading. One such system is diversity which mitigates the deleterious effects of fading. The three major types of diversity which may be employed are time diversity, frequency diversity and space diversity. Time diversity is found to be best obtained by the use of repetition, time interleaving and error detection and coding which is a form of repetition.
CDMA by its inherent nature possessing a wide band signal which offers a form of frequency diversity by spreading the signal energy over a wide bandwidth, resulting in a small part of the CDMA signal bandwidth experiencing selective fading effects.
Space or path diversity is obtained by providing multiple signal paths through simultaneously links from a mobile user through two or more cell sites. Path diversity may be obtained by exploiting the multipath environment through spread spectrum processing by allowing a signal arriving with different propagation delays to be received and processed separately. In U.S. Pat. No. 5,101,501 entitled Soft Handoff in a CDMA Cellular Telephone System, and U.S. Pat. No. 5,109,390 entitled Diversity Receiver in a CDMA Cellular Telephone System, examples of path diversity are illustrated. Further control of deleterious effects in a CDMA system may be realized by controlling transmitter power. Such a system for cell site mobile unit power control is disclosed in U.S. Pat. No. 5,056,109 entitled Method and Apparatus for Controlling Transmission Power in a CDMA Cellular Mobile Telephone System. Techniques as disclosed in U.S. Pat. No. 4,901,307 contemplate the use of coherent modulation and demodulation for both directions of the link in mobile satellite communications. A pilot carrier signal as a coherent phase reference for the satellite to mobile link and the cell to mobile link is disclosed. It is found, however, that the severity of multipath fading experienced in the terrestrial cellular environment with the resulting phase disruption of the channel precludes usage of coherent demodulation techniques for the mobile to cell link.
Relatively long PN sequences with each user channel being assigned a different PN sequence are also disclosed in U.S. Pat. No. 4,901,307. The different user signals may be discriminated upon reception employing the cross correlation between different PN sequences and the auto correlation of a PN sequence for all time shifts other than zero where both have a zero average value. Although the cross correlations average zero for a short time interval, such as an information bit time, the cross correlation follows a binomial distribution since PN signals are not orthogonal. As such, signals interfere with each other much the same as if they were wide bandwidth Gaussian noise resulting in other user signals or mutual interference noise ultimately limiting the achievable capacity.
Multipath can provide path diversity to a wide band PN CDMA system which uses greater than 1 MHz bandwidth if two or more paths are available with greater than one microsecond differential path delay. Two or more PN receivers can be employed to separately receive these signals. These signals typically will exhibit independence in multipath fading, i.e., they usually do not fade together, the outputs of the two receivers can be diversity combined. It is found that a loss in performance in this situation only occurs when both receivers experience fades at the same time, hence two or more PN receivers in combination with a diversity combiner may be employed utilizing a waveform that permits path diversity combining operations to be performed.
In U.S. Pat. No. 4,901,307 filed Oct. 17, 1986, issued Feb. 13, 1990, a communication system which accommodates a large number of users throughout a variety of user environments from high density urban to very low density rural is provided which results in a multiple access communication system having high simultaneous user capacity.
In U.S. Pat. No. 5,101,501 filed Nov. 7, 1989, issued Mar. 31, 1992, there is disclosed a CDMA cellular telephone system wherein the same frequency band is used for all cells employing CDMA waveform properties that provide processing gains which are also used to discriminate between signals that occupy the same frequency band.
In U.S. Pat. No. 5,103,459 filed Jun. 25, 1990, issued Apr. 7, 1992, there is disclosed spread spectrum communication techniques, particularly CDMA techniques, in the mobile cellular telephone environment which provide features to vastly enhance system reliability and capacity over other communication system techniques overcoming fading and interference while providing greater frequency reuse and enabling a substantial increase in the number of system users.
In U.S. Pat. No. 5,109,390 filed Nov. 7, 1989, issued Apr. 28, 1992, there is disclosed a CDMA cellular telephone system where the same frequency band is used for communication in all cells to provide a cellular telephone system in which a receiver design facilitates reception and processing of the strongest signals transmitted from one or more cell sites, the signals being multipath signals from a single cell site or signals transmitted by multiple cell sites.
In U.S. Pat. No. 5,233,626 filed May 11, 1992, issued Aug. 3, 1993, there is disclosed a repeater diversity spread spectrum communication system providing substantially fade free communications between a transmitter (1) and a receiver (7). A transmitted signal is relayed through a plurality of linear communications repeaters (3-6) that produce copies of the transmitted signal, the copies each arriving through an independently fading signal path. The receiver processes the received signal copies to equalize them to one another in delay, frequency, and phase, and then combines the multiple received and equalized signal copies to produce a composite signal having a greatly reduced fading depth.
In U.S. Pat. No. 5,267,261 filed Mar. 5, 1992, issued Nov. 30, 1993, there is provided a system for directing handoff in mobile station communication between base stations which employ code division multiple access techniques.
In U.S. Pat. No. 5,267,262 filed Oct. 8, 1991, issued Nov. 30, 1993, there is disclosed a CDMA cellular mobile telephone wherein the transmitter power of the mobile units are controlled so as to produce at the cell site a nominal received signal power from each and every mobile unit transmitter operating within the cell. Thus, the transmitter power is controlled in the terrestrial channel and the cell diversity environment so as to overcome deleterious fading without causing unnecessary system interference.
In U.S. Pat. No. 5,303,286 filed Mar. 29, 1991, issued Apr. 12, 1994, there is disclosed a radio communication system capable of servicing a roaming user or the like outside the range of terrestrial relay stations including a packet switched network and database of roaming users, a satellite communications system having at least one, but usually a plurality of orbiting satellites over a terrestrial satellite service area, a satellite control center and a plurality of terrestrial communication links wherein call setup is controlled by processors and databases onboard the orbiting satellites and wherein only after the satellite link for the communication channels is completed, does control and switching rely on ground base system such that the orbiting satellites are integrated into a ground based telephone network and tariff structure.
In U.S. Pat. No. 5,309,474 filed Mar. 27, 1992, issued May 3, 1994, there is disclosed spread spectrum communication techniques, particularly CDMA, in a mobile cellular telephone environment which provides features to vastly enhance system reliability and capacity over other communication system techniques.
In U.S. Pat. No. 5,416,797 filed Jan. 24, 1992, issued May 16, 1995, there is disclosed a system for constructing PN sequences that provide orthogonality between the users so that mutual interference will be reduced allowing higher capacity and better link performance, employing spread spectrum communication techniques, particularly CDMA, in a mobile cellular telephone environment.
In U.S. Pat. No. 5,715,297 filed Sep. 15, 1995, issued Feb. 3, 1998, there is disclosed a radio communication system capable of servicing a roaming user or the like outside the range of terrestrial relay stations which includes a packet switched network and database of roaming users, a satellite communications system having at least one, but usually a plurality of orbiting satellites over a terrestrial satellite service area, a satellite control center and a plurality of terrestrial communication links, wherein call setup is controlled by processors and databases onboard the orbiting satellites and wherein only after the satellite link for the communication channels is completed, does control and switching rely on ground based equipment such that the orbiting satellites are integrated to a ground based telephone network and tariff structure.
In U.S. Pat. No. 5,903,837 filed Sep. 22, 1997, issued May 11, 1999, there is disclosed a radio communication system capable of servicing a roaming user or the like outside the range of terrestrial relay stations which includes a packet switched network and database of roaming users, a satellite communications system having at least one, but usually a plurality of orbiting satellites over a terrestrial satellite service area, a satellite control center and a plurality of terrestrial communication links wherein call setup is controlled by processors and databases onboard the orbiting satellites and wherein only after the satellite link for the communication channel is completed, does control and switching rely on ground based equipment such that the orbiting satellites are integrated into a ground based telephone network and tariff structure.
In U.S. Pat. No. 6,072,768 filed Sep. 4, 1996, issued Jun. 6, 2000, there is disclosed a communication system having a satellite communication component comprising at least one satellite and at least one terrestrial gateway and also a wireless terrestrial communication component comprising at least one repeater and at least one mobile switching center, the gateway and switching center coupled together by a first mobile applications part network, the gateway and the mobile switching center further coupled to a terrestrial communication network, further including at least one dual mode or higher tri-mode user terminal comprising a first transceiver for bidirectionally communicating with the gateway through the satellite, a second transceiver for bidirectionally communicating with the mobile switching center through the repeater and a controller responsive to one of a user selected or a gateway selected protocol for selectively enabling either the first or the second transceiver for conveying a user communication to a terrestrial communication network.
In U.S. Pat. No. 6,640,236 filed Aug. 31, 1999, issued Oct. 28, 2003, there disclosed an apparatus for generating a PN sequence with an arbitrary number of bits where the number of bits is provided in parallel with each clock pulse, allowing the sequences to be generated at high speed when needed and allowing parallel processing in the acquisition and demodulation processes.
In U.S. Pat. No. 6,693,951 filed Jul. 23, 1999, issued Feb. 17, 2004, there is disclosed implementation of spread spectrum communication techniques, particularly CDMA, in a mobile cellular telephone environment which provides features that vastly enhance system reliability and capacity over other communication system techniques, overcoming, for example, fading and interference while promoting greater frequency reuse, enabling a substantial increase in the number of system users.
In U.S. Pat. No. 6,714,780 filed Jun. 12, 2001, issued Mar. 30, 2004, there is disclosed a multibeam communication system having a user terminal, a communications station for transmitting information to and receiving information from the user terminal and a plurality of beam sources where each beam source projects a plurality of beams and where a communication link between the user terminal and the communications station is established on one or more beams, providing a system and method for reducing call dropping rates while maintaining a desired level of beam source diversity.
In U.S. Pat. No. 6,839,007 filed Sep. 9, 2002, issued Jan. 4, 2005, there is disclosed embodiments which address the need for reliable transmission of higher priority data within a frame wherein an inner code is applied to one or more partial segments of a transmitted data frame, in addition to an outer code applied to the entire frame, the inner code segment being retained when the inner decoding decodes without error providing the benefit of reducing the number of retransmissions of higher priority data, as well as reducing delay for time sensitive segments of the frame.
Various satellite telephone systems have been proposed, including those as depicted in the FCC filing for "Authority to Launch and Operate a Satellite System to Provide Mobile Satellite Services in the 2 GHz Bands" dated Nov. 3, 2000, relating to the Globalstar® system, which is hereby incorporated by reference; the FCC filing in the matter of Mobile Satellite Ventures Subsidiary, LLC for "Minor Amendment of Application to Launch and Operate a Replacement L Band Mobile Service Satellite at 101° West" dated Nov. 18, 2003; and the FCC filing by Thoraya which depicts a one GEO satellite system to provide a satellite telephone service.
Thus, it can be seen from the inception of the telephone through its various phases of improvement, cellular to satellite cellular telephony, a vast number of advances have been made which provide a modern, efficient and affordable telephone system which today, in many cases, supplants the existing telephone system and may in the future do so on an increasing basis.
There is, however, a continuing demonstrated need to provide improved satellite constellation systems, preferably LEO systems, which provide multiple beams to a plurality of users and employ at least one gateway connected to a PSTN communicating with a user over the constellation where each of the users within a given frequency band is distinguished from another employing orthogonal codes.
Although previous patents such as U.S. Pat. No. 4,901,307 describe or reference a multi-beam satellite system, these beams are considered to cover fixed regions on the ground, which requires a GEO satellite. In this case, the same sort of hand-off of a user terminal from beam to beam can be used as is used in a terrestrial cellular system. However, the '307 patent does not address the case where the beams and satellites are rapidly moving as they are in a MEO or LEO system, since it was written in an era that preceded the satellite technology that enabled large numbers of relatively smaller satellites (such as Globalstar's®) to be economically and reliably launched and controlled. Therefore, the hand-off issues described in the '307 patent are much simpler than those encountered in the Globalstar® system or similar LEO or MEO systems, or even those encountered in GEO systems which have dynamically varying beam shapes, which is another technological advance that is now feasible in satellite systems. That patent also does not address packet data services, since those were not widely used in the time frame of the patent. Other patents that address packet data services also do not address the LEO, MEO or dynamic beam GEO systems. The present invention describes a multi-beam LEO, MEO or GEO satellite system that can be used to provide packet data services (in addition to voice) for mobile users, that can be either initiating or receiving packet data calls over the system, while communicating with either a fixed or mobile user anywhere in the world.

This patent is subject to a terminal disclaimer.

Satellite communication system for communicating packet data messages


The battery of the invention includes at least one electrochemical cell for use and recharging underwater, particularly seawater, at a pressure at or greater than atmospheric pressure. The battery has an anode, a cathode, an associated electrolyte in a housing, and a pressure compensation fluid which has a density greater than water, but preferably between the density of water and the density of the electrolyte. Preferably the pressure compensation fluid has a density of about 1.2 g/cm.sup.3, and is non-conductive. Apparatus to compensate for changes in volume are provided, as are components for the escape of internally generated gases.

1. Field of the Invention
This invention relates to electrical storage batteries, and in particular, relates to such batteries which may be safely used and recharged underwater, or which may be used in conditions subject to accidental flooding with water.
2. Description of the Related Art
Underwater vehicles, many of them relatively small and in the range of about eight feet long, are used for military, industrial and research purposes. Researchers often use underwater vehicles, mainly powered submarine boats and bathyspheres, under the ice, for example, to study ice mechanics and thickness, water thermoclines, electrical conductivity of water, and global warming. Batteries are often utilized as the electrical power source for the vehicles themselves as well as for various instruments in the vehicles, as disclosed, for example in, U.S. Pat. No. 5,379,714 of Lewis et al. The disclosure of the '714 patent and other patents and publications hereafter referred to are deemed incorporated herein by reference.
As used herein, the term battery means a single or multiple cell device for supplying electrical current by the electrochemical action of a wet or dry electrolyte and a pair of dissimilar electrodes. Because the batteries in the described vehicles are used in an underwater environment, even though they are typically enclosed and separated from the water in which the vehicles are used, particular problems can and do arise due to the underwater location. For example, such batteries may need to withstand high pressure exposure, rapid pressure change and temperature changes. It is also important that the battery be protected from entrance of seawater into any sensitive portions of the battery. The battery is also required to function in different orientations due to the vehicle's pitching and rolling, which can cause a battery to become inverted.
Rechargeable batteries are particularly useful for vehicles which must operate repetitively, and for vehicles which are unattended for extended periods of time for reasons of economy and convenience. Although batteries have been developed to meet the criteria discussed above, batteries known in the art are not safely rechargeable underwater, and must be brought to the surface to be recharged. Alternatively, replacement batteries, as opposed to rechargeable batteries, must be provided.
Gas release must also be accommodated in the design and use of a battery system. Few rechargeable cell type batteries are completely gas free, but considerable effort has been invested in cell design to minimize this problem. In particular, lead-acid cells have been characterized as giving rise to substantial amounts of gases during charge and particularly during overcharge, due to electrolysis of water and side reactions of the positive grid material with the electrolyte.
Currently available rechargeable batteries typically use a water-based chemistry. While charging, these batteries produce some hydrogen and/or oxygen due to electrolysis of the water. Upon overcharge, virtually all of the excess electrical energy applied to the battery produces these gases, either as H and O, or as H.sub.2 and O.sub.2. Some chemistries, e.g. nickel-cadmium, when overcharged at ordinary temperatures, catalyze and effectively recombine most of the evolved gases back into water, with the production of heat which causes the battery temperature to rise abruptly at the end of the charge. This temperature rise is often used to detect and terminate the charge phase. The charge is terminated once a certain maximum temperature is achieved, or upon a temperature rise, or indirectly through the effect of the rising temperature on the battery terminal voltage reflected by a decrease in voltage. At temperatures below 10.degree. C., this catalysis is reduced in efficiency and may allow increased hydrogen and oxygen evolution.
Hydrogen is explosive when mixed with oxygen over a very wide range of concentrations from about 4% to about 92% hydrogen. However, no charging strategy presently known, when used for hundreds or thousands of recharge cycles, can with absolute assurance prevent a critical amount of hydrogen and oxygen from being evolved so as to prevent a resulting explosive atmosphere. Only about 18 grams of water need be electrolyzed to result in 22.4 liters of hydrogen and 11.2 liters of oxygen at Standard Temperature and Pressure (STP) of 0.degree. C. and 760 mmHg. A single lead-acid, silver-zinc, or nickel-cadmium battery used in an underwater vehicle will typically contain hundreds of times this amount of water. Thus, charging of a battery in a closed container is not recommended or safe. Almost all manufacturers include a warning about this danger with their particular battery, in spite of claims that batteries do not evolve gas. Certain hydrogen-absorbing materials exist, but their efficacy at low temperatures is greatly reduced, and they do not remove the weight penalty imposed by the pressure housing required.
Batteries are sometimes placed in a pressure resistant housing in order to keep them dry. The pressure resistant housing imposes a severe weight penalty on portable underwater equipment and vehicles, particularly for submarine like vehicles designed for deep ocean use. The extreme pressures encountered in such environments mandate spherical or cylindrical housings with thick walls. The shape of these housings does not lend itself to efficient utilization by the battery shapes typically available. FIG. 1 is a diagram of a typical aqueous electrolyte rechargeable cell of a type which must be placed in a pressure resistant housing for underwater use.
Adapting batteries to be used under water "at depth" (a term which typically refers to pressures greater than atmospheric pressure) without a pressure resistant housing is called pressure compensation. Pressure compensation has been accomplished in the past by replacing spaces in the batteries which would normally contain air or gas, with a light mineral oil to keep out external water and keep the electrolyte from being lost or diluted. This has been done by Deep Sea Power and Light Co., Whittaker-Yardney Corp., and perhaps others, using lead-acid and silver-zinc batteries (see FIG. 2). According to the manufacturer, these batteries cannot be charged at depth--only at the surface. An oil-filled pressure-compensated battery system using a silver-zinc electrode system has been developed by Industrial Battery Plant, Japan Storage Battery Co., Ltd. as described in Oceans 82, Proceedings of Conference Sponsored by Marine Technology Society, IEEE Council on Oceanic Engineering, Washington, D.C., 1982, pages 50-56. The battery and connector boxes of this system are liquid tight and are filled with an oil having a density less than water, i.e. 0.80 to 0.88 g/cm.sup.3. Each cell is exposed to the box through a gas/liquid separator. Oil moves through conduits to equilibrate pressure, and a bladder is said to compensate the volume changes of gas, electrolyte and oil which are expected at submarine temperatures and pressures. Relief valves at the top of the box vent gas to the sea when the pressure rises in the system.
Other pressure compensation systems which use other light oils as the compensation fluid, when charged at increased pressure under water, eventually lose compensation oil due to the displacement of the oil by gas evolution. Gas evolution occurs primarily while the battery is being charged, and becomes rapid during overcharging. The gas evolution is due to the electrolytic decomposition of water 2 H.sub.2 .fwdarw.2H.sub.2 +O.sub.2. These gases (hydrogen and oxygen) may be initially produced in nascent form as H and O, and, at room temperature or above, may partially recombine harmlessly in certain battery systems. Recombination yields water and heat. However, as the above chemical equation indicates, two mols of water (36 grams or about 1.3 ounces), when electrolyzed, yields 2 mols of H.sub.2 and 1 mol of O.sub.2, totaling 3 mols of evolved gas. These 3 mols of evolved gas will amount to approximately 67.2 liters at STP. Such an amount is enough to displace an enormous amount of compensation fluid. Particularly upon subsequent descent to a greater depth, the lighter oils will be replaced by the heavier ambient water (density 1.0 g/cm.sup.3 to 1.04 g/cm.sup.3), which may intrude and replace the lost oil and gas, thus poisoning the battery system.
Under unusual circumstances such as catastrophic failure resulting in loss of compensating fluid (perhaps due to fracture or melting of the battery housing) losing the lighter-than-water compensating fluids causes the submarine vehicle to lose buoyancy. Loss of buoyancy may cause the submarine to descend uncontrollably. The submarine may then be destroyed due to crushing of the hull under extreme pressure, or may be difficult or impossible to recover due to extreme depth.
In addition, battery system vents are often used to provide repeated relief of a pressure condition within a battery. See, for example, the battery vent plug of Szymborski et al. (U.S. Pat. No. 4,328,290) which is arranged to prevent dropping of the internal pressure to zero upon venting while yet having a small relief-reseal pressure range, and Spillman et al. (U.S. Pat. No. 5,360,678) in which pressure compensation means may comprise bellows used together with vents.
It is therefore an object of this invention to provide a method of pressure-compensating a submersible battery which permits safe recharging at depth.
It is a further object of this invention to provide a heavier compensation fluid which remains properly partitioned thereby displacing the relatively lighter ambient water, and effectively preventing its intrusion into the cell electrolyte.
It is a further object of this invention to provide a battery which, if battery cell failure occurs, will not result in loss of buoyancy of the submarine or other type vehicle holding the battery.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.

Underwater rechargeable battery and method of manufacture


A hybrid brush seal is provided for sealing a circumferential gap between two machine components that are relatively rotatable with respect to each other having seal bristles mounted in a ring shape on a first machine component with bristle ends directed at the sealing surface of the second, rotating machine component. The bristle ends are kept from direct contact with the rotating machine component via one or more shoes which create a non-contact seal with the rotating machine component which is enhanced by the imposition of one or more spring elements connected between the machine component and shoes.

Turbomachinery, such as gas turbine engines employed in aircraft, currently is dependent on either labyrinth (see FIGS. 1A-1E), brush (see FIGS. 2A and 2B) or carbon seals for critical applications. Labyrinth seals provide adequate sealing, however, they are extremely dependent on maintaining radial tolerances at all points of engine operation. The radial clearance must take into account factors such as thermal expansion, shaft motion, tolerance stack-ups, rub tolerance, etc. Minimization of seal clearance is necessary to achieve maximum labyrinth seal effectiveness. In addition to increased leakage if clearances are not maintained, such as during a high-G maneuver, there is the potential for increases in engine vibration. Straight-thru labyrinth seals (FIG. 1A) are the most sensitive to clearance changes, with large clearances resulting in a carryover effect. Stepped labyrinth seals (FIGS. 1B and 1C) are very dependent on axial clearances, as well as radial clearances, which limits the number of teeth possible on each land. Pregrooved labyrinth seals (FIG. 1D) are dependent on both axial and radial clearances and must have an axial clearance less than twice the radial clearance to provide better leakage performance than stepped seals.
Other problems associated with labyrinth seals arise from heat generation due to knife edge to seal land rub, debris from hardcoated knife edges or seal lands being carried through engine passages, and excessive engine vibration. When seal teeth rub against seal lands, it is possible to generate large amounts of heat. This heat may result in reduced material strength and may even cause destruction of the seal if heat conducted to the rotor causes further interference. It is possible to reduce heat generation using abradable seal lands, however, they must not be used in situations where rub debris will be carried by leakage air directly into critical areas such as bearing compartments or carbon seal rubbing contacts. This also holds true for hardcoats applied to knife edges to increase rub capability. Other difficulties with hardcoated knife edges include low cycle fatigue life debits, rub induced tooth-edge cracking, and the possibility of handling damage. Engine vibration is another factor to be considered when implementing labyrinth seals. As mentioned previously, this vibration can be caused by improper maintenance of radial clearances. However, it can also be affected by the spacing of labyrinth seal teeth, which can produce harmonics and result in high vibratory stresses.
In comparison to labyrinth seals, brush seals can offer very low leakage rates. For example, flow past a single stage brush seal is approximately equal to a four knife edge labyrinth seal at the same clearance. Brush seals are also not as dependent on radial clearances as labyrinth seals. Leakage equivalent to approximately a 2 to 3 mil gap is relatively constant over a large range of wire-rotor interferences. However, with current technology, all brush seals will eventually wear to line on line contact at the point of greatest initial interference. Great care must be taken to insure that the brush seal backing plate does not contact the rotor under any circumstances. It is possible for severing of the rotor to occur from this type of contact. In addition, undue wire wear may result in flow increases up to 800% and factors such as changes in extreme interference, temperature and pressure loads, and rubbing speeds must be taken into account when determining seal life.
The design for common brush seals, as seen in FIGS. 2A and 2B, is usually an assembly of densely packed flexible wires sandwiched between two plates. The free ends of the wires protrude beyond the plates and contact a land or runner, with a small radial interference to form the seal. The wires are angled so that the free ends point in the same direction as the movement of the runner. Brush seals are sized to maintain a tight diametral fit throughout their useful life and to accommodate the greatest combination of axial movement of the brush relative to the rotor.
Brush seals may be used in a wide variety of applications. Although brush seal leakage generally decreases with exposure to repeated pressure loading, incorporating brush seals where extreme pressure loading occurs may cause a "blow over" condition resulting in permanent deformation of the seal wires. Brush seals have been used in sealing bearing compartments, however coke on the wires may result in accelerated wear and their leakage rate is higher than that of carbon seals.
One additional limitation of brush seals is that they are essentially unidirectional in operation, i.e., due to the angulation of the individual wires, such seals must be oriented in the direction of rotation of the moving element. Rotation of the moving element or rotor in the opposite direction, against the angulation of the wires, can result in permanent damage and/or failure of the seal. In the particular application of the seals required in the engine of a V-22 Osprey aircraft, for example, it is noted that during the blade fold wing stow operation, the engine rotates in reverse at very low rpm's. This is required to align rotor blades when stowing wings. This procedure is performed for creating a smaller aircraft footprint onboard an aircraft carrier. Reverse rotation of the engine would damage or create failure of brush seals such as those depicted in FIGS. 2A and 2B.
One attempt to limit wear of brush seals is disclosed in U.S. Pat. No. 5,026,252 to Hoffelner in which a sliding ring is interposed between the bristle pack of the seal and the moving element or rotor to avoid direct contact therebetween. The bristle ends are received within a circumferential groove in the sliding ring and are allowed to freely float or move within such groove. Although bristle wear may be reduced in this design, it is believed that the seal created at the interface of the sliding ring and rotor is unsatisfactory.
An improvement of prior brush seals, including that disclosed in the '252 patent to Hoffelner noted above, is found in my U.S. Pat. No. 6,428,009. In that design, one end of each of a plurality of seal bristles is fixed in an annular shape and mounted to the fixed machine component or stator while their opposite ends are attached to a number of individual shoes located proximate the rotating machine component or rotor. Prior to shaft rotation, the shoes are in contact with the rotor surface with preferably the leading edge of each shoe set to have less contact than the trailing edge of the shoe. When the rotor begins to rotate, a hydrodynamic wedge is created which lifts the shoe slightly off the surface of the shaft allowing the shoe to effectively float over the shaft at a design gap. It has been found that one limitation of the design disclosed in the '009 patent is a potential problem with "roll over" under pressure load, i.e. the shoes can tip or pivot in the axial direction thus creating a leakage path.
Carbon seals are generally used to provide sealing of oil compartments and to protect oil systems from hot air and contamination. Their low leakage rates in comparison to labyrinth or brush seals are well-suited to this application, however they are very sensitive to pressure balances and tolerance stack-ups. Pressure gradients at all operating conditions and especially at low power and idle conditions must be taken into account when considering the use of carbon seals. Carbon seals must be designed to have a sufficiently thick seal plate and the axial stack load path must pass through the plate as straight as possible to prevent coning of the seal. Another consideration with carbon seals is the potential for seepage, weepage or trapped oil. Provisions must be made to eliminate these conditions which may result in oil fire, rotor vibration, and severe corrosion.
According to the Advanced Subsonic Technology Initiative as presented at the NASA Lewis Research Center Seals Workshop, development of advanced sealing techniques to replace the current seal technologies described above will provide high returns on technology investments. These returns include reducing direct operating costs by up to 5%, reducing engine fuel burn up to 10%, reducing engine oxides of emission by over 50%, and reducing noise by 7 dB. For example, spending only a fraction of the costs needed to redesign and re-qualify complete compressor or turbine components on advanced seal development can achieve comparable performance improvements. In fact, engine studies have shown that by applying advanced seals techniques to just a few locations can result in reduction of 2.5% in SFC.


A motorless human-powered scooter is disclosed having a sturdy frame with a fixed position rear wheel and a steerable fork which carries a steerable front wheel. The front and rear wheels are substantially equal in diameter and each has a diameter of about one-third the total length of the scooter. A preferred manner for attaching the scooter's main tube to its bottom tube and deck is disclosed.

Outdoor sports such as bicycling and skateboarding have recently become very popular. Another exciting and challenging outdoor sport is scooter riding, which is similar both to skateboarding and to bicycling. Human powered-scooters are known in the art. Previous scooters generally have been designed for nonvigorous recreational activities, such as children's toys and light recreational use by adults.
Motorless scooters are two-wheeled vehicles which, unlike bicycles, do not use a gear and chain mechanism for power. Instead, scooters are propelled only by the rider pushing with his feet. Human powered scooters are safe and exciting alternatives to stationary bikes or treadmills.
The scooter rider may engage in jumping in a manner similar to jumping a bicycle or a skateboard. Jumping and landing increase the force placed on the scooter and the frame may bend or break if it is not strong enough to withstand these forces.
Previous scooters have had two small wheels or one small wheel and one larger wheel. For example, U.S. Pat. Nos. 1,701,410, 1,661,307, 1,535,167 and 1,615,403 show scooters with two small wheels. U.S. Pat. No. 3,336,046 shows a scooter with a small front wheel and a larger rear wheel.
Other scooters have had driving or propulsion mechanisms, such as U.S. Pat. Nos. 4,761,014 and 5,224,724.
U.S. Pat. No. 5,470,089 shows a scooter with two bicycle-sized wheels. The frame of the scooter is constructed such that two rigid and spaced rods extend downwardly and then horizontally. Several spaced links are perpendicularly coupled between the rods. A plate is coupled to the frame to define a platform where the rider may stand.
None of these previous scooters have had sufficiently sturdy construction to withstand the vigorous riding activity seen with current riders. There exists a need for scooters which withstand forces placed on the frame during vigorous riding. The previous scooters do not provide an apparatus primarily for the purpose of adult recreation and exercise which are constructed so that the frame of the scooter will withstand increased forces associated with vigorous use.


According to one aspect, embodiments of the invention provide a lacrosse training aid comprising at least one glove configured to be placed on the hand of a lacrosse player, the at least one glove comprising an integrated strap mechanism configured to couple the at least one glove to a lacrosse stick in a non-dominant configuration.

1. Field of the Invention
Aspects of the present invention relate generally to lacrosse stick training.
2. Discussion of Related Art
Lacrosse is a team sport played using a small rubber ball and a long-handled stick called a lacrosse stick. The head of the lacrosse stick is strung with loose mesh designed to catch and hold the lacrosse ball and can also be strung with hard mesh. Many different types of mesh may be utilized such as Canadian mesh, rocket pocket and normal mesh. Offensively, the objective of the game is to score by shooting the ball into an opponent's goal, using the lacrosse stick to catch, carry, and pass the ball to do so. Defensively, the objective is to keep the opposing team from scoring and to dispossess them of the ball through the use of stick checking and body contact or positioning.


An integrated circuit configuration for producing a clock signal includes an integrated inverter connected between an input terminal and an output terminal. A crystal is externally connected to the oscillator circuit. A feedback path of the inverter contains a phase-shifting element which effects a phase shift through 180.degree., so that conditions for oscillation continue to be provided if the crystal breaks.

Field of the Invention
The invention relates to an integrated circuit configuration having a crystal oscillator for producing an operating clock signal, including a crystal to be connected externally at first and second connection terminals for producing a phase shift of 180.degree., and an integrated inverter for producing a further phase shift of 180.degree., thus together effecting an overall phase shift of 360.degree., the inverter having an input and an output connected to the first and the second connection terminals.
Many integrated circuits, such as microcontrollers, in which a multiplicity of peripheral units are additionally integrated besides a microprocessor, have an oscillator which is suitable for the connection of a crystal. The Siemens data book entitled "Microcomputer Components", Microcontrollers, Data Catalog 1998, page 78, lower left-hand figure, shows how such an oscillator can be connected or wired up externally with a crystal. FIG. 2 of the instant application shows an additional internal circuit section which is described in detail below.
U.S. Pat. No. 4,571,5583 describes a crystal oscillator circuit in which the feedback path of the inverter contains two integrators that together effect a phase shift of 180.degree.. That phase shift through 180.degree. causes the oscillatory response of the oscillator to be less temperature-dependent and to be less dependent on manufacturing tolerances. A further generic circuit configuration having a crystal oscillator is described in U.S. Pat. No. 4,321,562.
With rising performance requirements, microcontrollers are being operated at higher and higher frequencies. The crystal disks therefore have to be made thinner and thinner, which means that the risk of breakage increases. That is particularly relevant in the automotive sector due to vibration, since such microcontrollers are used in that sector for engine control, ABS control or the like. Such crystal breakage causes the oscillator to stop and thus also leads to the failure of the entire system. In order to avoid that, a so-called emergency clock signal is often required, which can be achieved by additional circuit complexity.
Published European Patent Application 0 286 879 A1, corresponding to U.S. Pat. No. 4,816,776, discloses an integrated circuit configuration for monitoring an additionally integrated oscillator, in which an integrated oscillator is excited by an external frequency standard. A second integrated reserve oscillator produces a slower auxiliary clock signal which is constantly compared with the oscillator clock signal, and the system clock signal is then obtained from the faster clock signal. If the crystal fails, for example as a result of it breaking, the system changes over to the reserve oscillator.
A further possibility is using a PLL for producing the system clock signal, in which that PLL has a minimum frequency which depends on the minimum frequency of the voltage-controlled oscillator in the PLL. In the event of the crystal breaking, the frequency of the system clock signal reverts to the minimum frequency of the PLL. A further advantage of a PLL is that the oscillator frequency can be many times lower than that of the system clock signal, which means that crystals which are thicker and therefore less likely to break are used.
The disadvantage of all of those configurations is the relatively large amount of circuitry.

Integrated circuit replacement operating clock signal generator having a crystal oscillator


A method and system thereof for identifying records are described. Records on a node are distinguished from other records on the node by assigning each record a unique local identifier. When a record is moved from one node to another node, a unique global identifier is assigned to the record. A translation technique is employed to map the local identifier to the global identifier (and vice versa).

1. Field of the Invention
The present invention relates generally to the field of databases. Specifically, the present invention relates to a method and system for synchronizing data between multiple nodes.
2. Related Art
In the realm of hand-held computer systems (commonly referred to as personal digital assistants or PDAs), it is not uncommon for a data set to exist and be maintained both on the PDA and on at least one other device. For example, a user may maintain a calendar or address book on both the user's PDA and on another computer system (e.g., a personal computer system such as a desktop or laptop).
The entries in the data set can be referred to as records or data objects. When a change is made to a record in the data set residing on one device (hereinafter, also referred to as a node), it is desirable to have the data set on the other node be updated as well, so that the data set is synchronized on both nodes. Accordingly, processes have been developed to facilitate synchronizing the data sets on both nodes. These synchronization ("sync") processes are known in the art.
It is becoming more common for people to use more than one computer system. Many people use a computer system at home and another one at work, for example. Traditionally, synchronization occurs between a PDA and a personal computer system (PC), one PC at a time. The data sets on each of the PCs may be somewhat different, and so sophisticated techniques are employed to ensure that the proper records are transferred between the PDA and each PC during synchronization.
However, the paradigm in which the PDA serves in essence as the nexus between the users home and office computer systems is not as applicable as it once was. As computer systems are networked, multiple communication pathways between PDAs and computer systems can exist. Records may be frequently shared between users, and quite often are distributed and stored across many nodes. Some records may be accessible by multiple users working from different nodes. In any event, different users may update a record in different ways, and the modified record may be distributed over different pathways. Along the way, the record may be further modified.
Currently, each record in a data set is identified by a record identifier (record ID). The task of assigning IDs to records is relegated to the PDA. When the PDA receives or creates a new record, it assigns a new record ID. This scheme works reasonably well in the relatively closed system consisting of the user's PDA and PCs. However, as records are shared and distributed as described above, the conventional scheme results in the same record being identified by different record IDs on different PDAs, because each PDA assigns its own record IDs. With the same record being identified differently by each node, it is difficult to propagate the record, or changes to the record, across the nodes. If the record is identified differently at different nodes, then it becomes necessary to reconcile the record ID at one node with the record IDs at each of the other nodes. In essence, it becomes necessary to identify each record using each of its possible record IDs. This is equivalent to attaching multiple IDs to each record. As the record is distributed from node to node, the accumulation of record IDs by which the record may be known can become quite unwieldy. Therefore, the notion of each PDA assigning record IDs is not as workable as before.
Accordingly, what is needed is a new system and/or method for identifying records such that the same record is not assigned different record IDs. It is also important that different records not be given the same record ID. In addition, in the realm of PDAs, there are other factors to consider. For example, relative to PCs, PDAs have less memory capacity and less address space. Thus, it is desirable to minimize to a practical extent the memory resources needed by a record identification scheme. Thus, what is also needed is a record identification scheme that carefully allocates the available address space. The present invention provides a novel solution to these needs.

Generating coherent global identifiers for efficient data identification


A fog generator includes a reservoir for a liquid to be atomized, a plurality of ultrasonic transducers disposed in spaced relation to each other in the reservoir so as to be submerged within the liquid therein, a gas inlet duct extending through the reservoir, and a dome-shaped deflector overlying, and of larger diameter than, the gas inlet duct to deflect the gas flowing through the duct back towards the reservor to pick up liquid atomized by the transducers.

The present invention relates to a fog generator, and particularly to one useful in horticulture for growing plants aeroponically, or conventionally.
The invention is particularly useful in the fog-generator method for growing plants aeroponically (i.e. in air, rather than in soil), such as described in our prior U.S. Pat. No. 5,136,804. In such a method, the plant roots, and also the shoots and foliage, are subjected to a fog of atomized water, which may include other additives such as fertilizers, fungicides, etc. Utilizing a fog generator has a number of advantages over a water sprayer. Thus, when sprayers are used, they supply water at a relatively high rate so they must be intermittently operated, whereas a fog generator, supplying water at a much lower rate, can be continuously operated. As a result, utilizing a fog generator reduces the possibility of "stress drying" or "salting" of the plants which may occur in sprayer systems during the periods when the sprayers are not operated.


An invert emulsion suitable for drilling subterranean wells, in particular oil and gas wells is disclosed which includes an oleaginous phase, and a non-oleaginous phase and a protonated amine surfactant which stabilizes the invert emulsion in the absence of an alkaline reserve material. The protonated amine surfactant has the general formula: EQU [R--N.sup.+ --H.sub.3 ]B.sup.-. wherein R is a C.sub.12 to C.sub.22 alkyl group and B.sup.- is a conjugate base of an acid; and the protonated amine surfactant is present in an amount capable of stabilizing the invert emulsion in the absence of an alkali reserve. The practice of the present invention permits the use of a broad range of esters as the oleaginous phase including simple alkyl esters which previously susceptible to hydrolysis due to the presence of an alkaline reserve material.

1. Field of the Invention
The present invention is generally directed to an invert emulsion drilling fluid or mud suitable for drilling subterranean wells. More particularly, the present invention relates to an ester based invert emulsion possessing negative alkalinity as is defined herein.
2. Background
Invert emulsion fluids, i.e. emulsions in which the non-oleaginous fluid is the discontinuous phase and the oleaginous fluid is the continuous phase, are employed in drilling processes for the development of oil or gas sources, as well as, in geothermal drilling, water drilling, geoscientific drilling and mine drilling. Specifically, the invert emulsion fluids are conventionally utilized for such purposes as providing stability to the drilled hole, forming a thin filter cake, lubricating the drilling bore and the downhole area and assembly, and penetrating salt beds without sloughing or enlargement of the drilled hole.
Oil-based drilling fluids are generally used in the form of invert emulsion muds. An invert emulsion mud consists of three-phases: an oleaginous phase, a non-oleaginous phase and a finely divided particle phase. Also typically included are emulsifiers and emulsifier systems, weighting agents, fluid loss additives, viscosity regulators and the like, for stabilizing the system as a whole and for establishing the desired performance properties. Full particulars can be found, for example, in the Article by P. A. Boyd et al entitled "New Base Oil Used in Low-Toxicity Oil Muds" in the Journal of Petroleum Technology, 1985, 137 to 142 and in the Article by R. B. Bennet entitled "New Drilling Fluid Technology-Mineral Oil Mud" in Journal of Petroleum Technology, 1984, 975 to 981 and the literature cited therein.
The components of the invert emulsion fluids include an oleaginous liquid such as hydrocarbon oil which serves as a continuous phase, a non-oleaginous liquid such as water or brine solution which serves as a discontinuous phase, and an emulsifying agent. As used herein, emulsifying agent and surfactant are used interchangeably. The emulsifying agent serves to lower the interfacial tension of the liquids so that the non-oleaginous liquid may form a stable dispersion of fine droplets in the oleaginous liquid. A full description of such invert emulsions may be found in Composition and Properties of Drilling and Completion Fluids, 5th Edition, H. C. H. Darley, George R. Gray, Gulf Publishing Company, 1988, pp. 328-332, the contents of which are hereby incorporated by reference.
Lime or other alkaline materials are typically added to conventional invert emulsion drilling fluids and muds to maintain a reserve alkalinity. See, for example, API Bulletin RP 13B-2, 1990, p. 22 which describes a standard test for determining excess lime in drilling mud. See also, for example, U.S. Pat. No. 5,254,531 which employs lime along with an ester oil, a fatty acid, and an amine and EP 271943 which employs lime along with oil, water, and an ethoxylated amine. The generally accepted role of the reserve alkalinity is to help maintain the viscosity and stability of the invert emulsion. This is especially important in areas in which acidic gases such as CO.sub.2 or H.sub.2 S are encountered during drilling. Absent an alkaline reserve, acidic gases will weaken stability and viscosity of conventional invert emulsion fluids to the point of failure. That is to say the invert emulsion becomes so unstable that the continuous oleaginous phase and the discontinuous non-oleaginous phase irreversibly "flip" thus rendering the invert emulsion fluid not suitable for use as a drilling fluid. One of skill in the art should understand that due to the high cost of removing and disposing of the flipped mud from a borehole, the formation of flip mud is very undesirable. Further because the beneficial properties of the drilling fluid have been lost, (i.e. viscosity, pumpability and the ability to suspend particles) the likelihood of a blowout is greatly increased. Thus, one of ordinary skill in the art should understand that the maintenance of a alkalinity reserve is critical to the use of conventional invert emulsion drilling fluids and muds.

Ester based invert emulsion drilling fluids and muds having negative alkalinity