A disposable flossing device is disclosed. The disposable flossing device is adapted for use with the conventional dental handpiece or any other device providing rotary input motion. The disposable flossing device converts the rotary input motion to reciprocating linear motion so that the dental floss will reciprocate through a linear plane. In addition to flossing, other attachments to the conventional dental handpiece such as brushes and polishers can also be operated with the linear motion of the disclosed device.

It is well known in the field of dentistry that failure to remove plaque from dentition surfaces and debris between dentitions is a principal cause of dental diseases such as tooth decay and gingivitis for example. Removal of plaque and debris by brushing is the commonest and easiest method known. However, brushing is generally inadequate especially when self-administered. A more efficient and known technique is the cleaning of dentition surfaces and areas between such surfaces by using a dental tape or floss(hereinafter generally termed "floss") which is moved reciprocally over and between the dentition surfaces. Furthermore, the reciprocating motion of the floss as it is manipulated over and between the dentition surfaces is beneficial as a treatment for and prevention of periodontal diseases, such as gingivitis and the like. This beneficial result occurs since the free margin of the gingivi which is adjacent to the individual teeth of the dentition and forms the gingival sulcus can be readily reached by dental floss, although it is generally inaccessible to a brush or other instruments, and the sulci are subject to the invasion of plaque or colonies of bacteria which cause diseases of these tissues. Thus, floss, in general, is particularly beneficial in removing plaque and debris, as well as serving as a vehicle for the application of medication. On the other hand, dental tape or floss is inconvenient and awkward to handle.
Consequently, much development has been undertaken in the past to provide dental tape or floss in various forms which is more convenient to handle and use. In addition, much development has taken place to provide mechanical devices for the flossing of dentition surfaces. Therefore, past developments have broadly involved provision of dental tape or floss in various forms to render the same easier to use and the provision of mechanical devices to support or hold the dental tape or floss in a manner to that it can be employed with greater efficiency and facility.
As an example of such developments, U.S. Pat. No. 4, 172,687 discloses a flossing device which is manipulated by hand and provided with a pair of spaced, resilient arms having fingers extending therefrom. The fingers are equipped with knobs on their distal ends and a length of dental tape or floss having a grommet on each end is disposed over the knobs on the ends of the fingers. A somewhat similar device, but which is power driven, is disclosed in U.S. Pat. No. 4,014,354. The disclosure in this latter patent indicates that the dental tape or floss is tensioned between a pair of L-shaped arms attached to a handle which is adapted to be driven by the power element. On the other hand, U.S. Pat. No. 3,927,686 discloses a hand manipulated flossing device which includes a handle and an adjustable head provided with a single strand or a plurality of strands of dental tape of floss.
Still another dentition surface cleaning device is disclosed in U.S. Pat. No. 3,835,872 in which a flexible dental tape or floss disposed on a handle having a detachable yoke for tautly supporting a run of the tape, the tape being attached to a pair of anchor pins disposed on the handle and one of which is disposed on a reciprocable trigger mounted in the handle for the purpose of tensioning the tape. The tape per se is provided with non-elastic loops at each end which are disposed over the previously mentioned pins. U.S. Pat. No. 3,828,804 discloses still another apparatus which is a hand manipulated device for cleaning teeth that includes a handle with a nub disposed thereon and which is provided with extending, spaced arms having notches at the ends thereof. An endless or circular elastomeric dental floss or tape is disposed in the notches thereby passing across the space between the arms and around the nub. In a variation of the device, a simple length of elastomeric band is anchored in the notches of the arms by means of shim or heads.
A further dentition cleaning instrument is disclosed in U.S. Pat. No. 3,759,274 in which a strand of dental floss is mounted on an extended fork which supports the strand and permits an oscillating movement which is imparted thereto by a drive means. In addition, the device also includes a spool for carrying the strand for use in each subsequent cleaning cycle. A still further dentition cleaning device is disclosed in U.S. Pat. No. 3,667,483 in which the device includes a pair of projecting arms disposed on a support frame, the arms being provided with guides at their outer ends to receive and permit relative movement of floss which passes from a spool to a take-up reel mounted on the supporting frame. The floss is driven in a reciprocating manner through a device provided with means to alternately remove floss from the supply spool and feed it to the takeup spool after each use.
In U.S. Pat. No. 3,552,022 there is disclosed another powered dentition cleaning or polishing device. This patent discloses a tool having a conical stem portion which is adapted to be inserted in and removed from a handle in which a reciprocating socket is provided therefore. The operating end of the tool is wedgelike and pointed, two broad sides being rough in order to abrade dentition surfaces and a third side thereof being narrow and smooth in order to prevent injury to the gingiva. Another power cleaning device is disclosed in U.S. Pat. No. 3,534,745. This device includes a housing provided with spaced prongs and a dental tape or floss holder and supply unit adapted to be removeably attached to a power unit which imparts reciprocating motion to the tape as well as permitting the feeding of new tape to the unit after each use. Finally, U.S. Pat. No. 3,421,524 discloses a power driven dentition cleaning device including a power unit which is adapted to receive a cleaning unit which includes an elongated shaft provided with a pair of spaced tines. A dental tape or floss supply holding member is removeably positioned on the power unit and the dental tape or floss is fed therefrom through an eyelet in each of the tines and back to the supply holding member where it is taken up on a take-up spool.
Mention may also be made of U.S. Pat. No. 4,307,740, U.S. Pat. No. 4,830,032, and U.S. Pat. No. 5,069,233, all of which involve devices in which the floss is held in fixed position relative to the structure which supports it, and that structure, along with the floss, is power driven.
While the various devices disclosed in the above-mentioned patents are useful for cleaning dentition surfaces, they still exhibit various disadvantages. For example, many of them are extremely complex in structure and consequently relatively expensive to manufacture. In addition, many of the known structures are relatively difficult to employ, often being difficult to load and requiring complex adjustment to impart the required tautness to the dental tape or floss utilized therewith.
In addition, many of the known devices do not provide maximum contact of the floss with the dentition surfaces to be cleaned and, in addition, due to their construction, necessitate the use of more than the needed amount of dental tape or floss for carrying out a given cleaning operation.
The disadvantages of the above-described devices have been substantially eliminated by the devices and processes set forth in my prior patents, U.S. Pat. No. 4,339,957 and U.S. Pat. No. 5,400,811. In Pat. No. 4,339,957, there is disclosed a dental prophylaxis device which comprises in combination a housing means provided with an axial cavity and having a pair of spaced tines provided with slotted openings disposed thereon and projecting outwardly therefrom, stationary support means on the housing in the vicinity of the base of each of the tines and oscillating support means located on the housing between the bases of the tines and which is supported on a cylindrical sleeve that is disposed axially within the cavity of the housing, the housing means being adapted to be connected to driving means to drive the oscillating support means through the cylindrical sleeve.
The dental prophylaxis process disclosed in U.S. Pat. No. 4,338,957 comprises contacting the dentition surfaces to be treated with a dental floss having a thread segment which is provided with a non-elastic loop at one end and an elastic loop at the opposite end, reciprocating the thread segment over the surfaces of the dentition to be treated, while expanding and contracting the elastic loop in response to the application of tensile force to the dental floss as it reciprocates over the dentition surfaces and absorbing the tensile forces which is imparted to the dental floss when it encounters resistance as it reciprocates over the dentition surfaces and the elastic loop expands.
The device disclosed in my U.S. Pat. No. 5,400,811 comprises a housing, a pair of stationary tines extending therefrom adapted to receive and support a length of dental floss extending therebetween, said length of floss having a pair of free ends extending therefrom beyond said tines, an exposed oscillatable part mounted on said housing, means on said part for receiving said pair of free floss ends, and drive means in said housing operatively connected to said part for driving it in oscillation, whereby, when said part is driven in oscillation, said floss translates back and forth between said tines.
While my previous devices and process have substantially eliminated the disadvantage of prior devices, there still exists a need for further improvement. The present invention fulfills this need.
All of the prior flossing devices suffered from the deficiency that when activated the floss does not reciprocate in a linear plane. Rather, the movement of the floss in these prior flossing devices entailed reciprocation through an arc. Thus, the floss in contact with the dentition surface was in reality only the point at the bottom of the arc. It is thus an object of the present invention to provide a flossing device whereby the floss will reciprocate in a linear plane thus ensuring that a longer section of floss will contact the dentition surface during reciprocation. It is a further object of the present invention to simplify the prior flossing devices and provide a device that is disposable and can be readily adapted to the conventional dental handpiece.


An auto rack rail road freight car is provided for carrying low density, relatively high value, relatively fragile lading. The car has trucks that have multiple dampers in a four corner arrangement in the sideframes. The dampers may include damper wedges having primary and secondary wedge angles. The spring groups in the side frames are relatively soft, giving a low vertical bounce natural frequency. In an articulated embodiment, differentially placed ballast is mounted in a biased arrangement to load the coupler end trucks to encourage a dynamic response similar to the dynamic response of the internal trucks.

This invention can be used with the invention described in my co-pending U.S. patent application Ser. No. 09/920,437 filed Aug. 1, 2001, now U.S. Pat. No. 6,659,016.
Auto rack rail road cars are used to transport automobiles. Typically, auto-rack rail road cars are loaded in the "circus loading" manner, by driving vehicles into the cars from one end, and securing them in places with chocks, chains or straps. When the trip is completed, the chocks are removed, and the cars are driven out.
Automobiles are a high value, relatively fragile type of lading. Damage due to dynamic loading in the railcar may tend to arise principally in two ways. First, there are the longitudinal input loads transmitted through the draft gear due to train line action or shunting. Second, there are vertical, rocking and transverse dynamic responses of the rail road car to track perturbations as transmitted through the rail car suspension. It would be desirable to improve ride quality to lessen the chance of damage occurring.
In the context of longitudinal train line action, damage most often occurs from two sources (a) slack run-in and run out; (b) humping or flat switching. Rail road car draft gear have been designed against slack run-out and slack run-in during train operation, and also against the impact as cars are coupled together. Historically, common types of draft gear, such as that complying with, for example, AAR specification M-901-G, have been rated to withstand an impact at 5 m.p.h. (8 km/h) at a coupler force of 500,000 Lbs. (roughly 2.2×106 N). Typically, these draft gear have a travel of 2¾ to 3¼ inches in buff before reaching the 500,000 Lbs. load, and before "going solid". The term "going solid" refers to the point at which the draft gear exhibits a steep increase in resistance to further displacement. If the impact is large enough to make the draft gear "go solid" then the force transmitted, and the corresponding acceleration imposed on the lading, increases sharply. While this may be acceptable for ores, coal or grain, it is undesirably severe for more sensitive lading, such as automobiles or auto parts, rolls of paper, fresh fruit and vegetables and other high value consumer goods such as household appliances or electronic equipment. Consequently, from the relatively early days of the automobile industry there has been a history of development of longer travel draft gear to provide lading protection for relatively high value, low density lading, in particular automobiles and auto parts, but also farm machinery, or tractors, or highway trailers.
Historically, the need for slack was related, at least in part, to the difficulty of using a steam locomotive to "lift" (that is, move from a standing start) a long string of rail road cars with journal bearings, particularly in cold weather. For practical purposes, presently available diesel-electric locomotives are capable of lifting a unit train of one type of cars having little or no slack. Given the availability of locomotives that develop continuous high torque from a standing start, it is possible to re-examine the issue of slack action from basic principles. By eliminating, or reducing, the accumulation of slack, the use of short travel buff gear may tend to reduce the relative longitudinal motion between adjacent rail road cars, and may tend to reduce the associated velocity differentials and accelerations between cars. The use of short travel, or ultra-short travel, buff gear also has the advantage of eliminating the need for relatively expensive, and relatively complicated EOCC units, and the fittings required to accommodate them.
In terms of dynamic response through the trucks, there are a number of loading conditions to consider. First, there is a direct vertical response in the "vertical bounce" condition. This may typically arise when there is a track perturbation in both rails at the same point, such as at a level crossing or at a bridge or tunnel entrance where there may be a relatively sharp discontinuity in track stiffness. A second "rocking" loading condition occurs when there are alternating track perturbations, typically such as used formerly to occur with staggered spacing of 39 ft rails. This phenomenon is less frequent given the widespread use of continuously welded rails, and the generally lower speeds, and hence lower dynamic forces, used for the remaining non-welded track. A third loading condition arises from elevational changes between the tracks, such as when entering curves in which case a truck may have a tendency to warp. A fourth loading condition arises from truck "hunting", typically at higher speeds, where the truck oscillates transversely between the rails. During hunting, the trucks tend most often to deform in a parallelogram manner. Fifth, lateral perturbations in the rails sometimes arise where the rails widen or narrow slightly, or one rail is more worn than another, and so on.
There are both geometric and historic factors to consider related to these loading conditions. One historic factor is the near universal usage of the three-piece style of freight car truck in North America. While other types of truck are known, the three piece truck is overwhelmingly dominant in freight service in North America. The three piece truck relies on a primary suspension in the form of a set of springs trapped in a "basket" between the truck bolster and the side frames. For wheel load equalisation, a three piece truck uses one set of springs, and the side frames pivot about the truck bolster ends in a manner like a walking beam. The 1980 Car & Locomotive Cyclopedia, states at page 669 that the three piece truck offers "interchangeability, structural reliability and low first cost but does so at the price of mediocre ride quality and high cost in terms of car and track maintenance". It would be desirable to retain many or all of these advantages while providing improved ride quality.
In terms of rail road car truck suspension loading regimes, the first consideration is the natural frequency of the vertical bounce response. The static deflection from light car (empty) to maximum laded gross weight (full) of a rail car at the coupler tends to be typically about 2 inches. In addition, rail road car suspensions have a dynamic range in operation, including a reserve travel allowance.
In typical historical use, springs were chosen to suit the deflection under load of a full coal car, or a full grain car, or fully loaded general purpose flat car. In each case, the design lading tended to be very heavy relative to the rail car weight. For example, the live load for a 286,000 lbs. car may be of the order of five times the weight of the dead sprung load (i.e., the weight of the car, including truck bolsters but less side frames, axles and wheels). Further, in these instances, the lading may not be particularly sensitive to abusive handling. That is, neither coal nor grain tends to be badly damaged by poor ride quality. As a result, these cars tend to have very stiff suspensions, with a dominant natural frequency in vertical bounce mode of about 2 Hz. when loaded, and about 4 to 6 Hz. when empty. Historically, much effort has been devoted to making freight cars light for at least two reasons. First, the weight to be back hauled empty is kept low, reducing the fuel cost of the backhaul. Second, as the ratio of lading to car weight increases, a higher proportion of hauling effort goes into hauling lading, rather than hauling the railcar.
By contrast, an autorack car, or other type of car for carrying relatively high value, low density lading such as auto parts, electronic consumer goods, or white goods more generally, has the opposite loading profile. A two unit articulated autorack car may have a light car (i.e., empty) weight of 165,000 lbs., and a lading weight when fully loaded of only 35-40,000 lbs., per car body unit. That is, not only may the weight of the lading be less than the sprung weight of the rail road car unit, it may be less than 40% of the car weight. The lading typically has a high, or very high, ratio of value to weight. Unlike coal or grain, automobiles are relatively fragile, and hence more sensitive to a gentle (or a not so gentle) ride. As a relatively fragile, high value, high revenue form of lading, it may be desirable to obtain superior ride quality to that suitable for coal or grain.
One way to improve ride quality is to increase the dead sprung weight of the rail road car body. Another way to improve ride quality is to decrease the spring rate. Decreasing the spring rate involves further considerations. Historically the deck height of a flat car tended to be very closely related to the height of the upper flange of the center sill. This height was itself established by the height of the cap of the draft pocket. The size of the draft pocket was standardised on the basis of the coupler chosen, and the allowable heights for the coupler knuckle. The deck height usually worked out to about inches above top of rail. For some time auto rack cars were designed to a 19 ft height limit. To maximise the internal loading space, it has been considered desirable to lower the main deck as far as possible, particularly in tri-level cars. Since the lading is relatively light, the rail car trucks have tended to be light as well, such as 70 Ton trucks, as opposed to 100, 110 or 125 Ton trucks for coal, ore, or grain cars at 263,000, 286,000 or 315,000 lbs. gross weight on rail. Since the American Association of Railroads (AAR) specifies a minimum clearance of 5″ above the wheels, the combination of low deck height, deck clearance, and minimum wheel height set an effective upper limit on the spring travel, and reserve spring travel range available. If softer springs are used, the remaining room for spring travel below the decks may well not be sufficient to provide the desired reserve height. In consequence, the present inventor proposes, contrary to lowering the main deck, that the main deck be higher than 42 inches to allow for more spring travel.
As noted above, many previous auto rack cars have been built to a 19 ft height. Another major trend in recent years has been the advent of "double stack" intermodal container cars capable of carrying two shipping containers stacked one above the other in a well or to other freight cars falling within the 20 ft 2 in. height limit of AAR plate H. Many main lines have track clearance profiles that can accommodate double stack cars. Consequently, it is now possible to use auto rack cars built to the higher profile of the double stack intermodal container cars.
While decreasing the primary vertical bounce natural frequency appears to be advantageous for auto rack rail road cars generally, including single car unit auto rack rail road cars, articulated auto rack cars may also benefit not only from adding ballast, but from adding ballast preferentially to the end units near the coupler end trucks. As explained more fully in the description below, the interior trucks of articulated cars tend to be more heavily burdened than the end trucks, primarily because the interior trucks share loads from two adjacent car units, while the coupler end trucks only carry loads from one end of one car unit. It would be advantageous to even out this loading so that the trucks have roughly similar vertical bounce frequencies.
Three piece trucks currently in use tend to use friction dampers, sometimes assisted by hydraulic dampers such as can be mounted, for example, in the spring set. Friction damping has most typically been provided by using spring loaded blocks, or snubbers, mounted with the spring set, with the friction surface bearing against a mating friction surface of the columns of the side frames, or, if the snubber is mounted to the side frame, then the friction surface is mounted on the face of the truck bolster. There are a number of ways to do this. In some instances, as shown at p. 847 of the 1984 Car & Locomotive Cyclopedia lateral springs are housed in the end of the truck bolster, the lateral springs pushing horizontally outward on steel shoes that bear on the vertical faces of the side columns of the side frames. This provides roughly constant friction (subject to the wear of the friction faces), without regard to the degree of compression of the main springs of the suspension.
In another approach, as shown at p. 715 of the 1997 Car & Locomotive Cyclopedia, one of the forward springs in the main spring group, and one of the rearward springs in the main spring group bear upon the underside, or short side, of a wedge. One of the long sides, typically an hypotenuse of a wedge, engages a notch, or seat, formed near the outboard end of the truck bolster, and the third side has the friction face that abuts, and bears against, the friction face of the side column (either front or rear, as the case may be), of the side frame. The action of this pair of wedges then provides damping of the various truck motions. In this type of truck the friction force varies directly with the compression of the springs, and increases and decreases as the truck flexes. In the vertical bounce condition, both friction surfaces work in the same direction. In the warping direction (when one wheel rises or falls relative to the other wheel on the same side, thus causing the side frame to pivot about the truck bolster) the friction wedges work in opposite directions against the restoring force of the springs.
The "hunting" phenomenon has been noted above. Hunting generally occurs on tangent (i.e., straight) track as railcar speed increases. It is desirable for the hunting threshold to occur at a speed that is above the operating speed range of the rail car. During hunting the side frames tend to want to rotate about a vertical axis, to a non-perpendicular angular orientation relative to the truck bolster sometimes called "parallelogramming" or lozenging. This will tend to cause angular deflection of the spring group, and will tend to generate a squeezing force on opposite diagonal sides of the wedges, causing them to tend to bear against the side frame columns. This diagonal action will tend to generate a restoring moment working against the angular deflection. The moment arm of this restoring force is proportional to half the width of the wedge, since half of the friction plate lies to either side of the centreline of the side frame. This tends to be a relatively weak moment connection, and the wedge, even if wider than normal, tends to be positioned over a single spring in the spring group.
Typically, for a truck of fixed wheelbase length, there is a trade-off between wheel load equalisation and resistance to hunting. Where a car is used for carrying high density commodities at low speeds, there may tend to be a higher emphasis on maintaining wheel load equalisation. Where a car is light, and operates at high speed there will be a greater emphasis on avoiding hunting. In general, the parallelogram deformation of the truck in hunting is deterred by making the truck laterally more stiff. One approach to discouraging hunting is to use a transom, typically in the form of a channel running from between the side frames below the spring baskets. Another approach is to use a frame brace.
One way to address the hunting issue is to employ a truck having a longer wheelbase, or one whose length is proportionately great relative to its width. For example, at present two axle truck wheelbases may range from about 5′-3″ to 6′-0″. However, the standard North America track gauge is 4′-8½″, giving a wheelbase to track width ratio possibly as small as 1.12. At 6′-0″ the ratio is roughly 1.27. It would be preferable to employ a wheelbase having a longer aspect ratio relative to the track gauge. As described herein, one aspect of the present invention employs a truck with a longer wheelbase, preferably about 80 or 86 inches, giving a ratio of 1.42 or 1.52. This increase in wheelbase length may tend also to be benign in terms of wheel loading equalisation.
In a typical spring seat and spring group arrangement, the side frame window may typically be of the order of 21 inches in height from the spring seat base to the underside of the overarching compression member, and the width of the side frame window between the wear plates on the side frame columns is typically about 18″, giving a side frame window that is taller than wide in the ratio of about 7:6. Similarly, the bottom spring seat has a base that is typically about 18 inches long to correspond to the width of the side frame window, and about 16 inches wide in the transverse direction, that is being longer than wide. It may be advantageous to make the side frame windows wider, and the spring seat correspondingly longer to accommodate larger diameter long travel springs with a softer spring rate. At the same time, lengthening the wheel base of the truck may also be advantageous since it is thought that a longer wheelbase may ameliorate truck hunting performance, as noted above. Such a design change is counter-intuitive since it may generally be desired to keep truck size small, and widening the unsupported window span may not have been considered desirable heretofore.
Another way to raise the hunting threshold is to increase the parallelogram stiffness between the bolster and the side frames. It is possible, as described herein, to employ pairs of wedges, of comparable size to those previously used, the two wedges being placed side by side and each individually supported by a different spring, or being the outer two wedges in a three deep spring group, to give a larger moment arm to the restoring force and to the damping associated with that force.
The use of multiple variable friction force dampers in which the wedges are mounted over members of the spring group, is shown in U.S. Pat. No. 3,714,905 of Barber, issued Feb. 6, 1973. The damper arrangement shown by Barber is not apparently presently available in the market, and does not seem ever to have been made available commercially.
Notably, the damper wedges shown in Barber appear to have relatively sharply angled wedges, with an included angle between the friction face (i.e., the face bearing against the side frame column) and the sliding face (i.e., the angled face seated in the damper pocket formed in the bolster, typically the hypotenuse) of roughly 35 degrees. The angle of the third, or opposite, horizontal side face, namely the face that seats on top of the vertically oriented spring, is the complementary angle, in this example, being about 55 degrees. It should be noted that as the angle of the wedge becomes more acute, (i.e., decreasing from about 35 degrees) the wedge may have an undesirable tendency to jam in the pocket, rather than slide.
Barber, above, shows a spring group of variously sized coils with four relatively small corner coils loading the four relatively sharp angled dampers. From the relative sizes of the springs illustrated, it appears that Barber was contemplating a spring group of relatively traditional capacity—a load of about 80,000 lbs., at a "solid" condition of 3 1/16 inches of travel, for example, and an overall spring rate for the group of about 25,000 lbs/inch, to give 2 inches of overall rail car static deflection for about 200,000 lbs live load.
Apparently keeping roughly the same relative amount of damping overall as for a single damper, Barber appears to employ individual B331 coils (k=538 lb/in, (+/−)) under each friction damper, rather than a B432 coil (k=1030 lb/in, (+/−)) as might typically have been used under a single damper for a spring group of the same capacity. As such, it appears that Barber contemplated that springs accounting for somewhat less than 15% of the overall spring group stiffness would underlie the dampers.
These spring stiffnesses might typically be suitable for a rail road car carrying iron ore, grain or coal, where the lading is not overly fragile, and the design ratio of live load to dead sprung load is typically greater than 3:1. It might not be advantageous for a rail road car for transporting automobiles, auto parts, consumer electronics or other white goods of relatively low density and high value where the design ratio of live load to dead sprung load may be well less than 2:1, and quite possibly lying in the range of 0.4:1 to 1:1.
It has been noted that the frictional force produced by friction damper wedges differs depending on whether the damper is being loaded, or unloaded. In the terminology employed, the damper is being "loaded" when the bolster is moving downward in the sideframe window, since the spring force is increasing, and hence the load, or force on the damper is increasing. Similarly, the damper is being "unloaded" when the bolster is moving upward toward the top of the sideframe window, since the force in the springs, and hence the load in the wedges, is decreasing.
The equations can be written as
            While                                      loading                                              :                                                    F        d              =                  μ        c                          F        s                                    (                                    Cot                                            (                Φ                )                                      -                          μ              s                                )                                      1            +                                          (                                                      μ                    s                                    -                                      μ                    c                                                  )                                                          Cot                                                  (                  Φ                  )                                                      +                                          μ                s                                                          μ                c                                              )                                While                                      unloading                                              :                                                    F        d              =                  μ        c                          F        s                                    (                                    Cot                                            (                Φ                )                                      +                          μ              s                                )                                      1            +                                          (                                                      μ                    s                                    -                                      μ                    c                                                  )                                                          Cot                                                  (                  Φ                  )                                                      +                                          μ                s                                                          μ                c                                              )                    Where:                Fd=friction force on the sideframe column        Fs=force in the spring        μs=friction coefficient of the angled face on the bolster        μc is the coefficient of friction against the sideframe column        Φ is the included angle between the angled face on the bolster and the friction face bearing against the column
For a given angle, a friction load factor, Cf can be determined as Cf=Fd/Fs. This load factor Cf will tend to be different depending on whether the bolster is moving up or down. A graph of upward and downward load factors as a function of wedge angle is shown in FIG. 7 based on a μs of 0.2 and a μc of 0.4, values which are thought to be roughly representative of service conditions.
When the wheels encounter a perturbation in the rail, their reaction to the perturbation will tend to transmit a force through the suspension into the rail road car body. The force transmitted will tend to be the sum of the spring force plus the friction force in the dampers. For a relatively gentle ride, it is desirable that the damping force as the wheels move up relative to the car body not be excessive, and that the damping be stronger when the car body is moving upward relative to the wheels.
With a relatively sharply angled wedge, as typified by wedges in the 30-35 degree range such as appear to be shown by Barber, and as employed in wedges known to be commonly in use, the load factor may tend to be significantly higher when the bolster is moving downward relative to the side frame than when the bolster is moving upward. It may be desirable to lessen, or reverse this relationship, as may tend to occur for angles above about 40 to 45 degrees. (See FIG. 7).
In the past, spring groups have been arranged such that the spring loading under the dampers has been proportionately small. That is, the dampers have typically been seated on side spring coils, as shown in the AAR standard spring groupings shown in the 1997 Car & Locomotive Cyclopedia at pages 743-746, in which the side spring coils, inner and outer as may be, are often B321, B331, B421, B422, B432, or B433 springs as compared to the main spring coils, such that the springs under the dampers have lower spring rates than the other coil combinations in the other positions in the spring group. As such, the dampers may be driven by less than 15% of the total spring stiffness of the group generally.
In U.S. Pat. No. 5,046,431 of Wagner, issued Sep. 10, 1991, the standard inboard-and-outboard gib arrangement on the truck bolster was replaced by a single central gib mounted on the side frame column for engaging the shoulders of a vertical channel defined in the end of the truck bolster. In doing this, the damper was split into inboard and outboard portions, and, further, the inboard and outboard portions, rather than lying in a common transverse vertical plane, were angled in an outwardly splayed orientation.
Wagner's gib and damper arrangement may not necessarily be desirable in obtaining a desired level of ride quality. In obtaining a soft ride it may be desirable that the truck be relatively soft not only in the vertical bounce direction, but also in the transverse direction, such that lateral track perturbations can be taken up in the suspension, rather than be transmitted to the car body, (and hence to the lading), as may tend undesirably to happen when the gibs bottom out (i.e., come into hard abutting contact with the side frame) at the limit of horizontal travel.
The present inventor has found it desirable that there be an allowance for lateral travel of the truck bolster relative to the wheels of the order of 1 to 1½ inches to either side of a neutral central position. Wagner does not appear to have been concerned with this issue. On the contrary, Wagner appears to show quite a tight gib clearance, with relatively little travel before solid contact. Furthermore, transverse displacement of the truck bolster relative to the side frame is typically resiliently resisted by the horizontal shear in the spring groups, and by the pendulum motion of the side frames rocking on the crowns of the bearing adapters, these two components being combined like springs in series. Wagner's canted dampers appear to make lateral translation of the bolster stiffer, rather than softer. This may not be advantageous for relatively fragile lading. In the view of the present inventor, while it is advantageous to increase resistance to the hunting phenomenon, it may not be advantageous to do so at the expense of increasing lateral stiffness.
It is desirable that a relatively larger portion of the spring effort be used to load the dampers, with the employment of a larger damper wedge angle. As such, the same magnitude of damping force may tend to be achieved with a combination of relatively softer springs than previously used, with a larger included angle in the wedges. Alternatively, a greater damping force than before may be achieved with wedges having a relatively modest angle with springs of the same stiffness as before, the included angle being chosen in the 45 to 65 degree range. The opportunity to vary wedge angle and spring stiffness thus gives an opportunity to tune the amount of damping in some measure. In addition, it would be advantageous to use a larger included angle in the wedge, both for these reasons, and because wedges with a larger included angle may tend to be less prone to jamming and may result in more favourable dynamic behaviour as indicated by FIG. 7.
In the damper groups themselves, it is thought that parallelogram deflection of the truck such that the truck bolster is not perpendicular to the side frame, as during hunting, may tend to cause the dampers to try to twist angularly in the damper seats. In that situation one corner of the damper may tend to be squeezed more tightly than the other. As a result, the tighter corner may try to retract relative to the less tight corner, causing the damper wedge to squirm and rotate somewhat in the pocket. This tendency to twist may also tend to reduce the squaring, or restoring force that tends to move the truck back into a condition in which the truck bolster is square relative to the side frames.
Consequently, it may be desirable to discourage this twisting motion by limiting the freedom to twist, as, for example, by introducing a groove or ridge, or keyway, or channel feature to govern the operation of the spring in the damper pocket. It may also be advantageous to use a split wedge to discourage twisting, such that one portion of the wedge can move relative to the other, thus finding a different position in a linear sense without necessarily forcing the other portion to twist. Further still, it may be advantageous to employ a means for encouraging a laterally inboard portion of the damper, or damper group, to be biased to its most laterally inboard position, and a laterally outboard portion of the damper, or the damper group, to be biased to its most laterally outboard position. In that way, the moment arm of the restoring force may tend to remain closer to its largest value. One way to do this, as described in the description of the invention, below, is to add a secondary angle to the wedge.
In the terminology herein, wedges have a primary angle Φ, namely the included angle between (a) the sloped damper pocket face mounted to the truck bolster, and (b) the side frame column face, as seen looking from the end of the bolster toward the truck center. This is the included angle described above. A secondary angle is defined in the plane of angle Φ, namely a plane perpendicular to the vertical longitudinal plane of the (undeflected) side frame, tilted from the vertical at the primary angle. That is, this plane is parallel to the (undeflected) long axis of the truck bolster, and taken as if sighting along the back side (hypotenuse) of the damper.
The secondary angle β is defined as the lateral rake angle seen when looking at the damper parallel to the plane of angle Φ. As the suspension works in response to track perturbations, the wedge forces acting on the secondary angle will tend to urge the damper either inboard or outboard according to the angle chosen. Inasmuch as the tapered region of the wedge may be quite thin in terms of vertical through-thickness, it may be desirable to step the sliding face of the wedge (and the co-operating face of the bolster seat) into two or more portions. This may be particularly so if the angle of the wedge is large.
Split wedges and two part wedges having a chevron, or chevron like, profile when seen in the view of the secondary angle can be used. Historically, split wedges have been deployed as a pair over a single spring, the split tending to permit the wedges to seat better, and to remain better seated, under twisting condition than might otherwise be the case. The chevron profile of a solid wedge may tend to have the same intent of preventing rotation of the sliding face of the wedge relative to the bolster in the plane of the primary angle of the wedge. Split wedges and compound profile wedges can be employed in pairs as described herein.
In a further variation, where a single broad wedge is used, with a compound or other profile, it may be desirable to seat the wedge on two or more springs in an inboard-and-outboard orientation to create a restoring moment such as might not tend to be achieved by a single spring alone. That is, even if a single large wedge is used, the use of two, spaced apart springs may tend to generate a restoring moment if the wedge tries to twist, since the deflection of one spring may then be greater that the other.
When the dampers are placed in pairs, either immediately side-by-side or with spacing between the pairs, the restoring moment for squaring the truck will tend not only to be due to the increase in compression to one set of springs due to the extra tendency to squeeze the dampers downward in the pocket, but due to the difference in compression between the springs that react to the extra squeezing of one diagonal set of dampers and the springs that act against the opposite diagonal pair that will tend to be less tightly squeezed.
The bolster is typically permitted to travel laterally to either side relative to the side frames, and for the side frames to have limited angular rotation about an axis parallel to the longitudinal axis of the rail car more generally. It is desirable that after an initial perturbation, the bolster return to a central, angularly squared position. An increase in the normal force at the friction face, as discussed, may tend to return the side frames to a "square" condition relative to the truck bolster. In sideways displacement, return of the truck to a centered position may tend to cease when the friction in the dampers matches the lateral restoring force in the spring groups. This tendency may be reduced by the tendency of the springs to return to a laterally centered position as the truck works in the vertical bounce and warp conditions. However, it may be desirable to enhance this restoring tendency. In the view of the present inventor it may be advantageous to install some, or all of the springs in the inner and outer rows of the spring group at a slight anhedral angle relative to each other, so that they form a symmetrical V.

Rail road freight car with damped suspension


A substantially planar coil of a vacuum plasma processor has plural turns for exciting gas in the processor to a plasma state in response to r.f. coil energization. The coil is located outside the processor and surrounded by a shield tending to cause magnetic flux coupled from peripheral portions of the coil to the gas to be less than magnetic flux coupled from interior portions of the coil to the gas. The coil is arranged so magnetic flux derived from a center portion of an area circumscribed by the coil is less than the magnetic flux derived from all other areas circumscribed by the coil. The magnetic flux is such that the density of the plasma in the processor on a processed substrate is relatively uniform even though the coil exhibits transmission line properties so there are substantial peak-to-peak current variations along the length of the coil.

Various structures have been developed to supply r.f. fields from devices outside of a vacuum chamber to excite a gas in a plasma processor to a plasma state. The r.f. fields have been derived from electric field sources including capacitive electrodes, electromagnetic field sources including electron cyclotron resonators, and induction, i.e., magnetic, field sources including coils. The excited plasma interacts with a workpiece in the chamber to etch the workpiece or to deposit material on it. The workpiece can be a semiconductor wafer having a planar circular surface or a solid dielectric, e.g., a rectangular glass substrate used in flat panel displays or a metal plate.
A processor for treating workpieces with an inductively coupled planar plasma (ICPP) source is disclosed, inter alia, by Ogle, U.S. Pat. No. 4,948,458, commonly assigned with the present invention. In Ogle, the magnetic field that excites the plasma is derived from a planar coil positioned on or adjacent to a single planar dielectric window that extends in a direction generally parallel to the workpiece planar surface being processed. The coil is connected to be responsive to an r.f. source having a frequency in the range of 1 to 100 MHz (typically 13.56 MHz) and coupled to the coil by an impedance matching network. The coil is configured as a planar linear spiral having external and internal terminals connected to be responsive to the r.f. source. Coultas et al., U.S. Pat. No. 5,304,279 discloses a similar device employing plasma confinement using permanent magnets in combination with the planar spiral coil.
Cuomo et al., U.S. Pat. No. 5,277,751 and Ogle, U.S. Pat. No. 5,277,751 disclose variations of the aforementioned processors wherein the planar spiral coil is replaced by a solenoidal coil. The solenoidal coil is wound on a dielectric mandrel or the like and includes plural helical-like turns, a portion of which extend along the dielectric window surface. The remainder of the coil extends above the dielectric window. Opposite ends of the solenoidal coil are connected to an r.f. excitation source.
These inductive sources excite the plasma by heating electrons in the plasma region near the vacuum side of the dielectric window by oscillating inductive fields produced by the coil and coupled through the dielectric window. Inductive currents which heat the plasma electrons are derived from the r.f. magnetic fields produced by r.f. currents in the planar coil. The spatial distribution of the magnetic field is a function of the sum of the fields produced by each of the turns of the coil. The field produced by each of the turns is a function of the magnitude of r.f. current in each turn. For the spiral design disclosed by the Ogle '458 patent, the r.f. currents in the spiral coil are distributed to produce a ring shaped region where power is absorbed by the plasma. The ring shaped region abuts the vacuum side of the dielectric window. At the low pressures, in the 1.0 to 10 mTorr range, diffusion of the plasma from the ring shaped region produces a plasma flux peak in a central portion of the chamber, along a chamber center line away from the window. At intermediate pressure ranges, in the 10 to 100 mTorr range, gas phase collisions of electrons, ions, and neutrons in the plasma prevent substantial diffusion of the plasma charged particles outside of the annular region. As a result there is a relatively high plasma flux in a ring like region of the workpiece but low plasma fluxes in the center and peripheral workpiece portions. Hence, there are substantially large plasma flux variations between the ring and the volumes inside and outside of the ring.
Chen et al., U.S. Pat. No. 5,226,967 considers the adverse effects of reduced plasma flux at radial regions removed from the center of a planar spiral coil. In Chen '967, the field strength of magnetic fields generated by the planar coil and coupled to the plasma decreases along the chamber center line. The decrease is provided by increasing the thickness of the dielectric window center portion, relative to the thickness of other regions of the window. At pressures up to about 20 mTorr, the increased thickness of the solid dielectric material extending into the plasma shifts the ring shaped region for r.f. power absorption to a larger radius. The shift of the ring shaped region position changes the diffusion characteristics of this plasma generation region so diffusion is more uniform across the substrate diameter, particularly at the peripheral portion of the substrate.
In the device of the '967 patent, an electromagnetic shield that supports the dielectric window causes a decrease in plasma flux close to the center of the coil. This plasma flux density reduction occurs because the shield decreases coupling between the coil and an electromagnetic field resulting from the r.f. current applied to the coil. The magnetic fields produced by the largest diameter turn of the planar source frequently induce r.f. currents in the electromagnetic shield which supports the window, if the shield and largest turn are sufficiently close to each other. Power coupled to the shield results in (1) a decrease in the coupling efficiency of the r.f. excitation of the plasma and (2) a shift of the ring shaped power absorption region to a smaller diameter region since the magnetic field produced by the largest diameter turn of the coil does not couple as much as the inner turns. Substantial uniformity up to about 20 mTorr occurs as a result of diffusion of charged particles into the region below the center of the coil, where the window is thickest. However, as pressure increases above about 20 mTorr, where charged particular diffusion decreases appreciably, the plasma flux beneath the center of the coil, where the r.f. excitation is small, decreases relative to the flux in the other regions beneath the coil. Hence, there is non-uniform plasma flux on different portions of the workpiece.
The ring shaped region over which a planar coil couples r.f. power to the plasma can be shifted to larger diameters by removing the inner turns of the planar spiral. Fukusawa et al. in an article entitled "RF Self-Bias Characteristics in Inductively Coupled Plasma," Japanese Journal of Applied Physics, Vol. 32 (1993), pages 6076-6079, Part 1, No. 12(B), December 1993, discloses a single turn planar spiral coil for exciting gases in a plasma processor to a plasma condition. The disclosed coil has inner and outer dimensions of 120 and 160 mm and is 0.5 mm thick and is located in the vicinity of the periphery of a dielectric plate which serves as the top of the vacuum vessel. The ostensible purpose of the one turn coil is to produce a uniform plasma flux radial distribution. However, as illustrated in FIG. 6 of Fukusawa et al., the plasma flux is not particularly uniform even at a relatively low plasma processor pressure of 10 milliTorr, particularly for the types of r.f. excitation power which are required for plasma etching, in the 1 kilowatt range. For 1 kilowatt r.f. excitation of the single turn source, disclosed by Fukusawa et al., the plasma produces a substantial plasma flux peak (of 7.5.times.10.sup.11 ions cm.sup.-3), at a position approximately 4.0 centimeters from the center of the chamber. This peak occurs only on one side of the center axis, creating a significant non-radial asymmetry in the spatial distribution of the plasma. The one-turn spiral disclosed by Fukusawa et al. results in a shift in the coupling region to a larger diameter relative to the full spiral disclosed by Ogle in the '458 patent. The Fukusawa et al. devices also exhibit a nonradial asymmetry which equals or exceeds the radial nonuniformity in the spatial distribution of the plasma flux generated by a full spiral. The range of pressures over which the one turn coil can be operated is also limited since this coil relies on diffusion to shift plasma from the ring shaped plasma generation region near the periphery of the chamber to the center of the chamber. At pressures above 10 milliTorr, collisions of charge and uncharge particles in the plasma result in a severe decrease in plasma flux in the center region of the chamber.
It is, accordingly, an object of the present invention to provide a new and improved substantially planar coil for excitation of a gas in an r.f. vacuum plasma processor to a plasma state.
Another object of the invention is to provide a new and improved planar coil in an r.f. vacuum plasma processor, which coil is arranged to provide a relatively uniform plasma flux over the entire processed surface of a treated workpiece.
Another object of the invention is to provide a new and improved planar coil for a vacuum plasma processor that can operate at relatively high pressures, above 15 milliTorr, wherein the coil is arranged to provide a relatively uniform plasma flux on a workpiece.
Another object of the invention is to provide a new and improved planar coil in a plasma processor, which coil is arranged to provide a relatively uniform plasma on a treated workpiece, even though a shield is employed with the plasma processor to shield the coil from its surrounding environment.
Another object of the invention is to provide a new and improved planar coil for a plasma processor that operates at relatively high pressures, above 15 milliTorr, wherein the coil is arranged to provide a relatively uniform plasma flux on a workpiece.

Vacuum plasma processor having coil with small magnetic field in its center


The present actuator includes an inner cylinder closed at one end by an end cap and concentrically mounted in a reservoir tube. A fluid reservoir is formed between the inner cylinder and the reservoir tube. A piston is slidably mounted in the Y inner cylinder, dividing an interior volume of the inner cylinder into first and second chambers. A hollow piston rod is secured at its lower end to the piston and extends beyond the inner cylinder. A separator tube is mounted on the end cap and extends through the piston and into the piston rod to provide a fluid conduit from the reservoir to an external source of controlled pressurized fluid.

1. Field of the Invention
The present invention relates generally to vehicular suspension systems, and in particular is concerned with an active suspension single-acting hydraulic actuator with damping capabilities.
2. Description of the Related Art
Many active vehicular suspension systems include a hydraulic actuator to selectively vary the distance between a wheel assembly and a body. When a road input is received to the wheel assembly, the actuator compresses. When the road input is removed, the actuator rebounds or extends. Fluid from a control source such as a pressurized reservoir accepts fluid from and returns fluid to the actuator. The rate of compression and rebound of the actuator can be controlled to provide a desired rate of damping.

Active suspension actuator with control flow through the piston rod


A grenade launching apparatus launches a number of grenades and has a conller and a launcher. The controller controls the launching and includes a selector which is responsive to operator input for selecting one or more of the grenades to be launched. The controller also includes a display for indicating that a selected grenade has been launched. The launcher is for launching one or more of the grenades and includes a firing circuit which is responsive to the selector. The firing circuit activates the launcher to launch each selected grenade. The launcher also includes a launch detector for detecting that a selected grenade has been launched by the firing circuit. The display of the controller is responsive to the launch detector.

This invention generally relates to grenade launching systems and, in particular, such a system for launching a variety of grenades from a number of launch tubes and for indicating the status of the launch tubes.
Present grenade launching systems in this field are often mounted on an armored vehicle, such as a tank, and the grenades are generally housed in launching tubes outside of the vehicle while the operator remains inside. Thus, controlling the launching of a number of grenades requires penetrations through the hull of the tank, generally through the turret. Wiring for communication from a control portion to a launching portion of the system passes through the holes. Any hole, however, weakens the armor plating which makes the vehicle more susceptible to attack and destruction from armor piercing weapons. Therefore, it is desirable to limit the number and size of hull penetrations.
Presently available grenade launchers are not adaptable for use with a variety of types of grenades. A number of different grenade types may be necessary during combat, such as: smoke emitting, visibility screens, millimeter wave screens, infrared screens, and the like. The different types of grenades are designed to thwart different detection schemes for locating tanks. Therefore, it is desirable to be able to launch specific types of grenades discriminately, i.e., singularly or in combination. Present systems, however, do not provide for individual launch tube control.
Similarly, present grenade launchers do not provide an inventory, or status report, for which grenades have been launched and which grenades are available for launching.

The United States of America as represented by the Secretary of the Army


A safety directional line for underground mining that can be adjusted during to conform with any local codes. The line is constructed from high strength polypropylene which is non-conductive. A flame retardant is added to the polypropylene to make it flame resistant. There are flame retardant and non-conductive directional indicator cones evenly spaced and positioned such that they are pointing along the axis of the line. The cones are placed on the line such that when someone is exiting the mine his hand slides along the slope of the cone and meets little resistance. In the event that the miner is traveling the wrong direction, his hand will meet the flat surface of the cone and come to a stop, indicating that he is traveling in the wrong direction. There is fluorescent tape on the cones to make it more clearly visible to one trying to exit the mine. The tape is formed in an X on the flat surface of the cone indicating that it is the wrong direction. Additionally, the tape is placed parallel to the axis of the cone along the conical surface indicating the correct direction of travel. The rope is connected at one end by a solid bronze ring and at the other end by a solid bronze swivel hook or a solid fixed hook. The bronze ring and hook are non-sparking and non-corrosive.

1. Field of the Invention
The present invention relates to safety lines for coal miners. More specifically, the invention is a safety guide line for assisting miners in dark areas, and the method of securing the line.
2. Description of the Related Art
There are several dangers that are inherent to mining operations. Within a coal mine there are numerous tunnels and pathways, only a few of which lead directly to the outside. In an emergency situation inside a mine, it is easy for even experienced miners to lose their direction. The tunnels are extremely dark, and in the event that a fire breaks out, the situation is far worse.
Several states have mandated that some sort of escape route markers or lines be utilized within the mine in order for miners to find their way to the outside with little visibility. Each state has set its own regulations concerning the distance which can separate each of the markers along the safety line. For example, Virginia requires that there be 75 feet between directional indicators, while West Virginia requires there be 25 feet between directional indicators.
What is needed is a safety directional line for underground mining which is easily followed by miners and which has indicators along the line which can be adjusted at the manufacturing stage such that the distance between adjacent indicators can be modified to comply with local requirements. It is imperative that the line be able to withstand great stress as there would likely be several people placing strain on the line at one time.
Mine safety lines and markers have been disclosed in prior patents. U.S. Pat. No. 4,179,160 issued on Dec. 18, 1979 to Sabo discloses a mine life line system which utilizes conical markers along the line such that when the miner is leaving the mine in the proper direction his hand slides smoothly along the cone. When he is heading in the wrong direction, his hand meets with an abrupt slope and is stopped. The line is supported by a spring loaded support which engages the floor and ceiling of the mine shaft. The drawback of the Sabo patent is that the conical indicator members are integrally formed with the line such that they can not be adjusted to account for the different requirements among states as in the present invention.
U.S. Pat. No. 4,401,050 issued on Aug. 30, 1983 to Britt et al. discloses a phosphorescent escape route indicator. The indicator is in the form of an adhesive strip that can be applied to the surface of walls or stairways to aid in delineating escape routes or access routes to emergency equipment during emergency situations. The patent to Britt et al. does not teach the use of conical members along a guide wire as in the present invention.
U.S. Pat. No. 4,844,000 issued on Jul. 4, 1989 to Clement discloses a direction indicating clamp for attachment to fire fighting hoses which indicates direction to exit the building. The clamps disclosed in Clement are not clearly visible in dark situations such as mining operations. The fire fighter must grab the hose and search for an indicator clamp. The Clement patent does not teach the use of fluorescent indicating material with the direction indicator or the line itself as in the present invention.
U.S. Pat. No. 5,027,741 issued on Jul. 2, 1991 to Smith et al. discloses a direction indicating means along a fire hose such that when a fire fighter is attempting to exit a building he can follow the directional indicators along the surface of the hose. If the fire fighter is traveling in the wrong direction the indicator means will resist motion in that direction. If he is traveling in the correct direction, his hand will glide easily along the hose. The patent to Smith et al. does not disclose the use of adjustable indicators as in the present invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a safety directional line for underground mining solving the aforementioned problems is desired.

Safety directional line for underground mining and method of making same


A switching device including a GaN substrate; an unintentionally doped GaN layer on a first surface of the GaN substrate; a regrown unintentionally doped GaN layer on the unintentionally doped GaN layer; a regrowth interface between the unintentionally doped GaN layer and the regrown unintentionally doped GaN layer; a p-GaN layer on the regrown unintentionally doped GaN layer; a first electrode on the p-GaN layer; and a second electrode on a second surface of the GaN substrate.

Resistive random access memory (RRAM) is recognized as one of the most promising memories due to its excellent scalability, low programming voltage, and fast write/read speed. For stand-alone and large capacity nonvolatile memory (NVM), the cross-point (or crossbar) array is an attractive architecture for configuring the RRAM. To cut off the sneak path current of the unselected cells for a large-scale cross-point array, RRAMs with self-rectification characteristics can be used, or a selector device (with asymmetry or nonlinearity) can be added in series with the RRAM cell at each cross-point. Some threshold switching selector devices have been proposed, including as p-n diodes, bidirectional varistors, mixed-ion-electronic-conduction (MIEC) devices, ovonic threshold switching (OTS) devices, metal-insulator transition (MIT) devices, and programmable metallization cell (PMC) devices. However, these devices can have a limited lifetime under certain environmental conditions.

GaN-based threshold switching device and memory diode

Arizona Board of Regents on behalf of Arizona State University


The capacitance of a shielded capacitive load cell is determined so as to minimize the effect of stray or parasitic capacitance between the load cell and other objects including the shield. The load cell conductors are coupled across input and output terminals of an operational amplifier that is tied to a reference voltage. A constant current is applied to the load cell, and the resulting rate of change in voltage at the amplifier output is measured as a representation of the load cell capacitance. In a vehicle seat sensor application including an electromagnetic interference shield between the load cell and the seating surface, the amplifier output is coupled to the load cell electrode furthest from the shield, the amplifier maintains the other load cell electrode at a virtual reference voltage, and the shield is tied to the reference voltage.

Various sensing technologies have been utilized to classify the occupant of a vehicle seat for purposes of determining whether to enable or disable air bag deployment, and/or for purposes of determining how forcefully an air bag should be deployed. The present invention is directed to an approach in which at least one capacitive load cell is installed in a vehicle seat, and the capacitance of the load cell is measured to provide an indication of the weight applied to the seat and/or the distribution of the applied weight. In general, capacitive load cells are well known in the sensing art, such as in the U.S. Pat. No. 4,266,263 to Haberl et al., issued on May 5, 1981. Capacitive load cells have also been applied to vehicle seats for sensing occupant weight and distribution; see, for example, the U.S. Pat. Nos. 4,836,033 to Seitz; U.S. Pat. No. 5,878,620 to Gilbert et al.; U.S. Pat. No. 6,448,789 to Kraetzl; and U.S. Pat. No. 6,499,359 to Washeleski et al.
One of the problems encountered with using a capacitive load cell in a vehicle seat is that stray or parasitic capacitance between the load cell and other objects, including objects resting on or under the seat, tend to influence measurement of the load cell capacitance. Another problem is electromagnetic interference from various electrical devices both inside and outside the vehicle. And in applications that include more than one capacitive load cell or a multi-plate sensor such as disclosed in the aforementioned U.S. Pat. No. 4,836,033 to Seitz, conductive or wet objects placed on the seat can capacitively couple the cells.
The problems associated with electromagnetic coupling and interference can be addressed to some degree by shielding the load cell, as mentioned in the aforementioned U.S. Pat. No. 6,499,359 to Washeleski et al. An analogous approach is suggested in the U.S. Pat. No. 6,703,845 to Stanley et al. in regard to a sensor designed to capacitively interact with a seat occupant, where a driven shield is placed between the sensor and a seat heater element disposed beneath the sensor. However, introducing a shield significantly increases problems associated with stray or parasitic capacitance. Accordingly, what is needed is a capacitive load cell and sensing circuit that provides an accurate and reliable measure of load cell capacitance.

Shielded capacitive load cell apparatus responsive to weight applied to a vehicle seat


An electronic system and method for online searching by a customer for currently available service providers in their geographical area for a specific needed service. The system is programmed to permit service providers to input into the system that they are currently available to provide service. The system can also permit the service provider to also enter later times that they will also be available to provide their services. The system is programmed to preferably only list service providers who are available to provide the desired service at the time requested by the customer as opposed to listing all service providers who can provide the requested service that are registered with the electronic system.

Current mobile Apps and online websites for searching for service providers typically provide a static list of service providers for a geographical area. It is then up to consumer to review the information and contact the service provider to set up an appointment. The information typically provided from the search fails to inform the consumer/searcher of the current availability of the service providers listed in the results. Thus, in the event the consumer needs immediate service attention (i.e. busted water pipe, etc.) the consumer has no idea of whether the number they are calling will be able to provide such immediate service. Thus, often the consumer spends a large amount of time until they find a service provider who can handle the immediate needs. The below disclosed system and method are directed to overcoming the above-identified problem with conventional online searching for local service providers.

Electronic system and method for connecting currently available nearby service providers with customers in need of service


Parameters being a measure for a characteristic of a channel or of a pair of channels, wherein the parameter is a measure for a characteristic of the channel or of the pair of channels with respect to another channel of a multi-channel signal can be quantized more efficiently using a quantization rule that is generated based on a relation of an energy measure of the channel or the pair of channels and an energy measure of the multi-channel signal. With generation of the quantization rule taking into account a psycho acoustic approach, the size of an encoded representation of the multi-channel signal can be decreased by coarser quantization without significantly disturbing the perceptual quality of the multi-channel signal when reconstructed from the encoded representation.

Recently, multi-channel audio reproduction techniques are becoming more and more important. In the view of an efficient transmission of multi-channel audio signals having 5 or more separate audio channels, several ways of compressing a stereo or multi-channel signal have been developed. Recent approaches for the parametric coding of multi-channel audio signals (parametric stereo (PS), "Binaural Cue Coding" (BCC) etc.) represent a multi-channel audio signal by means of a down-mix signal (could be monophonic or comprise several channels) and parametric side information, also referred to as "spatial cues", characterizing its perceived spatial sound stage.
A multi-channel encoding device generally receives—as input—at least two channels, and outputs one or more carrier channels and parametric data. The parametric data is derived such that, in a decoder, an approximation of the original multi-channel signal can be calculated. Normally, the carrier channel (channels) will include subband samples, spectral coefficients, time domain samples, etc., which provide a comparatively fine representation of the underlying signal, while the parametric data do not include such samples of spectral coefficients but include control parameters for controlling a certain reconstruction algorithm instead. Such a reconstruction could comprise weighting by multiplication, time shifting, frequency shifting, phase shifting, etc. Thus, the parametric data includes only a comparatively coarse representation of the signal or the associated channel.
The binaural cue coding (BCC) technique is described in a number of publications, as in "Binaural Cue Coding applied to Stereo and Multi-Channel Audio Compression", C. Faller, F. Baumgarte, AES convention paper 5574, May 2002, Munich, in the 2 ICASSP publications "Estimation of auditory spatial cues for binaural cue coding", and "Binaural cue coding: a normal and efficient representation of spatial audio", both authored by C. Faller, and F. Baumgarte, Orlando, Fla., May 2002.
In BCC encoding, a number of audio input channels are converted to a spectral representation using a DFT (Discrete Fourier Transform) based transform with overlapping windows. The resulting uniform spectrum is then divided into non-overlapping partitions. Each partition has a bandwidth proportional to the equivalent rectangular bandwidth (ERB). Then, spatial parameters called ICLD (Inter-Channel Level Difference) and ICTD (Inter-Channel Time Difference) are estimated for each partition. The ICLD parameter describes a level difference between two channels and the ICTD parameter describes the time difference (phase shift) between two signals of different channels. The level differences and the time differences are normally given for each channel with respect to a reference channel. After the derivation of these parameters, the parameters are quantized and finally encoded for transmission.
Although ICLD and ICTD parameters represent the most important sound source localization parameters, a spatial representation using these parameters can be enhanced by introducing additional parameters.
A related technique, called "parametric stereo" describes the parametric coding of a two-channel stereo signal based on a transmitted mono signal plus parameter side information. There, 3 types of spatial parameters, referred to as inter-channel intensity difference (IIDs), inter-channel phase differences (IPDs), and inter-channel coherence (IC) are introduced. The extension of the spatial parameter set with a coherence parameter (correlation parameter) enables a parametrization of the perceived spatial "diffuseness" or spatial "compactness" of the sound stage. Parametric stereo is described in more detail in: "Parametric Coding of stereo audio", J. Breebaart, S. van de Par, A. Kohlrausch, E. Schuijers (2005) Eurasip, J. Applied Signal Proc. 9, pages 1305-1322)", in "High-Quality Parametric Spatial Audio Coding at Low Bitrates", J. Breebaart, S. van de Par, A. Kohlrausch, E. Schuijers, AES 116th Convention, Preprint 6072, Berlin, May 2004, and in "Low Complexity Parametric Stereo Coding", E. Schuijers, J. Breebaart, H. Purnhagen, J. Engdegard, AES 116th Convention, Preprint 6073, Berlin, May 2004.
The international publication Wo 2004/008805 A1 teaches, how a multi-channel audio signal can be advantageously compressed by combining several parametric stereo modules, thus realizing a hierarchical structure to derive a representation of the original multi-channel audio signal comprising a down-mix signal and parametric side information.
Within the BCC and parametric stereo (PS) approach, a representation of the level differences (also called intensity differences ICLD or energy differences IID) between audio channels is a vital part of a parametric representation of a stereophonic/multi-channel audio signal. Such information and other spatial parameters are transmitted from the encoder to the decoder for each time/frequency slot. In the view of coding efficiency, it is therefore of high interest to represent these parameters as compactly as possible while preserving audio quality.
In BCC coding, the level differences are represented relative to a so-called "reference channel" and are quantized on a uniform scale in units of dB relative to a reference channel. This does not optimally exploit the fact that channels with low level with respect to the reference channel are subject to a significant masking effect when listened to by human listeners. In the extreme case of a channel having no signal at all, the bandwidth used by parameters describing this particular channel is completely wasted. In the more common case, where one channel is much fainter than another channel, that is a listener can hardly hear the faint channel during the playback, a less precise reproduction of the faint channel would also lead to the same perceptual quality of the listener, as the faint signal is mainly masked by the stronger signal.
To explain the situation and the problems arising when encoding a multi-channel signal, reference is made to FIG. 10a where a commonly used 5-channel signal is illustrated. The 5-channel configuration is having a left rear channel 101 (A, having a signal a(t)), a left front channel 102 (B, having a signal b(t)), a center channel 103 (C, having a signal c(t)), a right front channel 104 (D, having a signal d(t)) and a right back channel 105 (E, having a signal e(t)). Intensity relations between single channels or channel pairs are marked with arrows. Hence, the intensity distribution between the front left channel 102 and the front right channel 104 is marked r1 (110), the intensity distribution between the left back channel and the right back channel is marked r4 (112). The intensity distribution between the combination of the left front channel 102 and the right front channel 104 and the center channel 103 is marked r2 (114) and the intensity distribution between the combination of the back channels and the combination of the front channels is marked r3 (116).
When, for example, a simple monologue is recorded, most of the energy would be contained in the center channel 103. In this example, especially the back channels will contain only little (or 0) energy. Therefore, parameters describing the properties of the back channels are merely wasted in this example, since mainly the center channel 102 or the front channels will be active during the play back.
Based on FIG. 10a, ways of computing the energy distribution between channels or channel combinations are described within the following paragraph.
FIG. 10a illustrates a multi channel parameterization for a five channel speaker set-up where the different audio channels are indicated by 101 to 105; a(t) 101 represents signal of the left surround channel, b(t) 102 represents the signal of the left front channel, c(t) 103 represents the signal of the center channel, d(t) 104 represents the signal of the right front channel, e(t) 105 represents the signal of the right surround channel. The speaker set-up is divided into a front part and a back part. The energy distribution between the entire front channel set-up (102, 103 and 104) and the back channels (101 and 105) are illustrated by the arrow in FIG. 10a and indicated by the r3 parameter. The energy distribution between the center channel 103 and the left front 102 and right front 103 channels are indicated by r2. The energy distribution between the left surround channel 101 and the right surround channel 105 is illustrated by r4. Finally, the energy distribution between the left front channel 102 and the right front channel 104 is given by r1. Since r1 to r4 are parameterizations of different regions it is also clear that beside energy distribution also other essential region properties can be parameterized, as for example the correlation between the regions. Additionally for each parameter r1 to r4 a local energy can be calculated. For example the local energy of r4 is the summed energy of channel A 101 and E 105.LocalEnergyr4=E[a2(t)]+E[e2(t)].
Where E[.] is the expected value as defined by
      E              [              f                          (          x          )                    ]        =            1      T                          ∫        0        T                                    f                                (                          x                                            (                t                )                                      )                                                        ⅆ            t                    .
FIG. 10b shows a multi-channel audio decoder built by hierarchically ordering parametric stereo modules, as for example described in WO 2004/008805 A1. Here, the audio channels 101 to 105, as introduced in FIG. 10a, are reproduced step by step from a single monophonic down-mix signal 120 (M) and corresponding side information by a first two-channel decoder 122, a second two-channel decoder 124, a third two-channel decoder 126, and a fourth two-channel decoder 128. As can be seen, in the treelike structure in FIG. 10b, the first two-channel decoder decomposes the monophonic down-mix signal 120 into two signals fed into the second and the third two-channel decoders 124 and 126. Therein, the channel fed into the third two-channel decoder 126 is a combined channel, being combined from the left back channel 101 and the right back channel 105. The channel fed into the second two-channel decoder 124 is a combination of the center channel 103 and a combined channel which is again being a combination of the front left channel 102 and of the front right channel 104.
Thus, after the second step of the hierarchical decoding, the left back channel 101, the right back channel 105, the center channel 103, and a combined channel, being a combination of the front left channel 102 and the front right channel 104 are reconstructed, using the transmitted spatial parameters, that are comprising a level parameter for use by each of the two-channel decoders 122, 124, and 126.
In the third step of the hierarchical decoding, the fourth two-channel decoder 128 derives the front left channel 102 and the front right channel 104, using a level information transmitted as side information for the fourth two-channel decoder 128. Using a prior art hierarchical decoder as shown in FIG. 10b, the desired energy for each single output channel follows from various different parametric stereo modules between the input signal and each output signal. In other words, the energy of a specific output channel can depend on the IID/ICLD parameters of multiple parametric stereo modules. In such a treelike structure of connected parametric stereo modules, also a non-uniform quantization of IID parameters can be applied within each parametric stereo module to produce IID values, which are then used by a decoder as part of the side information. This would exploit the benefits of non-uniform IID quantization locally (i.e. within each parametric stereo module individually), nonetheless it is sub-optimum because quantization in each module ("leafs") is carried out independently of the energies/level of other audio channels that may be high in relative level and, therefore, produce masking.
This is possible, since "leaf" modules are not aware of the global level distribution at a higher tree level (e.g. the "root" module). Each leaf has its own corresponding IID/ICLD parameter, which indicates the energy distribution from its input toward output channels. For example, the IID/ICLD parameter of leaf "r3" (processed by the first two-channel decoder 122) may indicate that 90% of the incoming energy should be sent to leaf r2, while the remaining energy (10%) should be sent to leaf r4. This process is repeated for each leaf in the tree. Since each energy distribution parameter is represented with limited accuracy, the deviation between the desired and the actual energy of each output channel A to E depends on the quantization errors in the IID/ICLD parameters, as well as on the energy distribution (and hence propagation of quantization errors). In other words, as the same quantization table is used for a certain parameter type, e.g. ICC or IID, within all parameterization stages r1 to r4, the IID/ICLD quantization is performed optimal only locally. This means that for each parameterization stage r1 to r4, the error in output energy of the (local) output channels is maximum for the weakest output channel in prior art implementations.
As detailed in the previous paragraphs, the quantization of level parameters (IID or ICLD) or other parameters such as ICC, phase differences or time differences describing the spatial perception of a multi-channel audio signal is still sub-optimal, since bandwidth may be wasted for spatial parameters describing channels that are mainly masked due to low energy within the channel.

Energy dependent quantization for efficient coding of spatial audio parameters

Fraunhofer-Gesellschaft zur Foerderung der Angewandten Forshung E.V.


A shelf-supporting assembly is provided with a vertical standard having a front and back portion, a shelf bracket extending outwardly from the vertical standard, a flange at a base portion of the shelf bracket extending inwardly in parallel with the front portion of the vertical standard, hook-shaped projection extending from the flange, spaced members defining gaps therebetween connecting the front portion of the vertical standard to the back portion, with the hook-shaped projections projecting through the gap defined between the spaced members, removably and supportably attaching the shelf bracket to the vertical standard.

The present invention relates generally to adjustable supports for shelving, and more particularly to shelf supporting assemblies using vertical standards with shelf supporting brackets thereon.
Support assemblies for shelving and the like, using vertical standards and shelf supporting elements which may be readily assembled to each other and adjusted for variations in height without tools and auxiliary locking screws or levers, are common in the art. Examples of such assemblies are found in U.S. Pat. 3,136,520 to Reiss, U.S. Pat. No. 3,234,897 to Berk, U.S. Pat. No. 3,502,293 to Bard, U.S. Pat. No. 3,604,669 to Asher, and U.S. Pat. No. 4,531,698 to Sharber. However, the vertical standards of the prior art while functional are unattractive with exposed screw holes and engagement slots for receiving a bracket.


Laser driver systems and methods are provided for controlling a laser driver coupled to a suitable laser source. The laser driver comprises a plurality of current sources, including at least one bias current source and at least two switched current sources. To control the laser driver, a laser power control signal is provided for each switched current source that corresponds to a desired laser output power. An output power error measure is defined based upon an error between a measured laser output power and the desired laser output power for each switched current source and a control system is characterized in which the output power error measures combine to change a magnitude of each of the switched current sources and the bias current source(s) such that the output power error measures converge over time.

The present invention relates to electrophotographic devices, and in particular, to current driver circuits and methods of controlling current driver circuits in electrophotographic devices.
In electrophotography, an imaging system forms a latent image by exposing select portions of an electrostatically charged photoconductive surface to laser light. For example, the imaging system may sweep a laser beam across the photoconductive surface in a scan direction as the photoconductive surface advances in a process direction that is orthogonal to the scan direction. For each sweep of the beam, a corresponding laser is modulated to write a plurality of print elements (Pels). Essentially, the density of the electrostatic charge on the photoconductive surface is altered in areas exposed to the laser beam relative to those areas unexposed to the laser beam, thus forming a latent image on the photoconductive surface in a manner that corresponds with associated image data. The latent electrostatic image thus created is developed into a visible image by exposing the photoconductive surface to toner, which contains pigment components and thermoplastic components. When so exposed, the toner is attracted to the photoconductive surface in a manner that corresponds to the electrostatic density altered by the laser beam.
The toner pattern is subsequently transferred from the photoconductive surface to the surface of a print substrate, such as paper, which has been given an electrostatic charge opposite that of the toner. A fuser assembly then applies heat and pressure to the toned substrate before the substrate is discharged from the apparatus. The applied heat causes constituents including the thermoplastic components of the toner to flow into the interstices between the fibers of the medium and the applied pressure promotes settling of the toner constituents in these voids. The toner solidifies as it cools adhering the image to the substrate.
Due to inherent imprecision in the imaging system, the swept beam may have bow and/or skew in its scan path. Moreover, there may be nonlinearity in the spacing between adjacent Pels due to imprecision in the imaging system optics. To compensate for such scanning errors, it is known to subdivide each Pel into a plurality of slices, i.e., subPels. During printing operations, the imaging system attempts to compensate for scanning errors by selectively controlling the number of slices per Pel and/or selectively controlling for each Pel, which slices the laser beam is modulated ON and which slices the laser beam is modulated OFF. However, as scan rates increase, e.g., due to increased printed page rates, the time available to the imaging system to write each slice of each Pel decreases. This places a burden on the imaging system, including the video control functions, the data transmission paths, and the laser diode driver(s) to reliably produce the short video pulse Pel slices.

Current driver and power control for electrophotographic devices


A taking lens system includes, in order from an object side thereof, a first lens group (negative refracting), a second lens group (positive refracting), an aperture stop and a third lens group (positive refracting). Focusing from an infinite distance to a finite distance is performed by setting the second lens group and the third lens group such that the position of the second lens group upon focusing on a finite distance is located on an image side of the taking lens system with respect to the position of the second lens group upon focusing on an infinite distance and the position of the third lens group upon focusing on a finite distance is located on an object side of the taking lens system with respect to the position of the third lens group upon focusing on an infinite distance, while the first lens group remains fixed.

The present invention relates generally to a taking lens and an imaging device that incorporates the same, and more particularly to a taking lens well fit for use on interchangeable lens cameras and an imaging device that incorporates the same.
So far, taking lens systems of the negative-positive-positive type with a leadoff negative lens group have been proposed in the art.
For some taking lenses of the negative-positive-positive type with a negative lens group out front wherein a front lens group is designed to move for focusing, however, it is required to rely on means for preventing entrance of dust into a lens barrel during focusing. With power-operated focusing, there is a problem that much power is consumed because of movement of a lens group susceptible of a large lens diameter.
A problem with taking lens systems of the type wherein the first lens group stays fixed is that aberrations are likely to fluctuate with focusing.

Taking lens, and imaging device incorporating the same


This invention concerns a pull boring cutter head assembly for machining long bores such as hydraulic cylinders and includes the use of support bearing blocks projecting from the cutter head to support the latter during cutting operations. The blocks are automatically radially adjustable under suitable biasing.

Pull boring has been known for many years and consists essentially of pulling a rotating cutter head axially through a tubular member to machine cut the inner surface of the member. The members being machined are usually of considerable length. It is also usually desirable that the machining operation be done speedily and give a desired fine surface finish. Preferably the operation should be a single cut operation.
Members which are machined in this way are borehole linings and cylinders for hydraulic piston and cylinder assemblies.
The cutter heads generally used today comprise a body adapted to be coupled to the driving shaft and carrying a series of cutter tips. The cutting edges of the tips extend radially and are parallel to the direction of travel in use. The cutting tips extend rearwardly from the cutting edges parallel to the axis of the cutter head.
There are a plurality of cutting tips, usually three, equally spaced apart around the periphery of the cutting head. The outer edges of the cutting tips provide bearing surfaces for the rotating cutter head in the member which is being bored.
The pull boring heads described cannot be operated at high speed or under heavy cutting conditions essentially because of the very limited bearing surface provided by the cutter tips. Use results in wear of the cutter tips further resulting in loss of gauge of the machined bore and still further the cutting tips tend to chatter. This in turn results in a poor quality finish to the bore, and further to a short cutting tip lifetime.
It is the object of this invention to provide a cutter head for pull boring operations which is more satisfactory than those referred to above.