Patent Grant
6932541
The present invention relates generally to a wave forming apparatus and is partially concerned with water rides of the type provided in water-based amusement parks, particularly a wave forming apparatus and method for forming surfable waves, or a water toy.
Naturally occurring waves occur in the ocean and also in rivers. These waves are of various types, such as moving waves which may be of various shapes, including tubular and other breaking waves. A relatively rare type of wave in nature is the standing wave, which has a steep, unbroken and stable wave face. This type of wave can have enough power and velocity to support surfing on the wave face without causing the wave to decay rapidly. This wave, if forced to decay, for example by overly obstructing the flow, reforms naturally when the obstructions are removed. Natural standing waves have been shown to occur where water flows across natural river bed formations, known as anti-dunes. Upon flow over anti-dunes, the water flow rises into a natural standing wave. Natural standing waves occur in the Waimea Bay river mouth of the Waimea River on the Hawaiian island of Oahu, on the Snake River in Wyoming, and several other places.
Surfers are constantly searching for good surfing waves, such as tubular breaking waves and standing waves. There are only a few locations in the world where such waves are formed naturally on a consistent basis. Thus, there have been many attempts in the past to create artificial waves of various types for surfing in controlled environments such as water parks. In some cases, a sheet flow of water is directed over an inclined surface of the desired wave shape. Therefore, rather than creating a stand-alone wave in the water, the inclined surface defines the wave shape and the rider surfs on a thin sheet of water flowing over the surface. This type of apparatus is described, for example, in U.S. Pat. Nos. 5,564,859 and 6,132,317 of Lochtefeld. In some cases, the inclined surface is shaped to cause a tubular form wave. Sheet flow wave simulating devices have some disadvantages. For example, since these systems create a fast moving, thin sheet of water, they produce a different surfing experience to a real standing wave.
In other prior art wave forming devices, a wave is actually simulated in the water itself, rather than being defined by a surface over which a thin sheet of water flows. U.S. Pat. No. 6,019,547 of Hill describes a wave forming apparatus which attempts to simulate natural antidune formations in order to create waves. A water-shaping airfoil is disposed within a flume containing a flow of water, and a wave-forming ramp is positioned downstream of the airfoil structure. In other prior art arrangements, such as U.S. Pat. No. 3,913,332 of Forsman, a wave generator is driven around a circular body of water in order to create waves. This arrangement is also complex and will produce traveling waves, not standing waves.
It is an object of the present invention to provide a new and improved wave forming apparatus and method.
According to one aspect of the present invention, a wave forming apparatus is provided, which comprises a channel for containing a flow of water, the channel having an inlet end connected to a water supply, a base, and spaced side walls, a weir in the base at the inlet end of the channel, and at least one bed form in the channel downstream of the weir, the bed form having a leading end and a trailing end, an upwardly inclined upstream face extending downstream of the leading end, an upper portion, and a downwardly inclined downstream face extending from the upper portion to the trailing end, the weir and bed form each extending outwardly to the side walls to define a primary water flow path from the inlet over the weir and bed form, and a secondary flow passageway provided in the channel, the secondary flow passageway having a first end communicating with the primary water flow at a location adjacent the trailing end of the bed form, and a second end communicating with the primary water flow at a location upstream of the first end.
In an exemplary embodiment of the invention, the first end of the secondary flow passageway comprises a first vent extending across the full width of the bed form. The second end may comprise a second vent extending across the full width of the bed form, or may comprise spaced second vents adjacent opposite sides of the bed form, each vent extending across the upper portion of the bed form. The first and second vents may be connected together via ducting or passageways through the bed form. Alternatively, the bed form may comprise a hollow shell so that the vents communicate via the chamber within the hollow shell.
This arrangement will tend to create a standing wave at the leading end of the bed form and any subsequent bed form. The provision of a secondary flow channel within the bed form communicating with a vent at the trailing edge of the bed form will enhance production of a stable standing wave at the next bed form in the channel, where two or more successive bed forms are provided. A secondary flow passageway may also be provided in the weir. In the exemplary embodiment, the side walls of the channel do not extend vertically upwardly from the top of the bed forms, but instead have outwardly angled, shallow inclined portions which taper slowly upwardly from the opposite sides of the weir and bed forms. Alternatively, the side portions on opposite sides of the channel extend outwardly either horizontally or at a slightly downwardly inclined angle on opposite sides of the channel containing the bed forms. In practice, the outer side portions or side walls may extend outwardly from the channel at an angle relative to the horizontal of +10° to −5°. This has been found to enhance the standing wave formation capabilities of the apparatus, and also provides a shallow lead-in portion for individuals prior to riding a standing wave, and for exiting the ride.
Water flows along the secondary flow passageway in either direction, depending on the conditions. It has been found that the provision of the secondary flow path enhances the formation of a stable standing wave at the upstream face of the bed form, and at any other bed forms downstream of the first bed form. Thus, additional secondary flow passageways will be provided, one for each wave-forming bed form. Adjustable valves or the like may be provided in the secondary flow passageways in order to vary the secondary flow rate. Additionally, several separate gates may be provided across the width of the first vent or the flow passageway, and these gates, if closed sequentially, can produce a lateral breaking wave.
In an exemplary embodiment of the invention, the trailing end of the bed form has an abrupt vertical drop off, such that the uppermost region of the trailing end is raised up above the channel bottom by a predetermined tail elevation. This has been found to enhance the standing wave formation properties of the apparatus. In fact, with an abrupt trailing end drop off in the waveform in a predetermined elevation range, the secondary passageways may be eliminated altogether, and standing waves may still be created. The tail elevation factor (TEF), or ratio of the top surface distance at the trailing end of the bed form above the channel bottom to the elevation of the top or peak of the next bed form above the channel bottom, may be in the range from 0.125 to 0.75 while still producing a rideable standing wave. Waves will still be produced at ratios above 0.75.
The tail elevation need not be constant across the entire width of the bed form. For example, TEF may be zero at one side of the channel and 0.8 at the other side. The tail elevation may be permitted to self-adjust based on water pressure. This will produce an oscillating wave.
In an exemplary embodiment of the invention, a series of identical bed forms are provided at spaced intervals along the channel, so that a series of standing waves may be formed. The channel cross section may be deeper in the wave forming area than at the outer sides of the bed forms, and may have gradually outwardly sloping side walls. This tends to return water to the center of the flume or channel, and also prevents too much water from escaping around the sides of the bed forms.
According to another aspect of the present invention, a method of forming waves is provided, which comprises the steps of directing water from a reservoir at one end of a channel having a base and spaced side walls into the channel and over a weir at the inlet end of the channel, directing water in the channel in a primary flow path over at least one bed form in the channel downstream of the weir, the bed form having a leading end and a trailing end, an upwardly inclined upstream face extending downstream of the leading end, an upper portion, and a downwardly inclined downstream face extending from the upper portion to the trailing end, and directing a secondary flow of water along a secondary flow passageway having a first end communicating with the primary water flow at a location adjacent the trailing end of the bed form, and a second end communicating with the primary water flow at a location upstream of the first end, whereby a stable standing wave is formed downstream of the bed form.
The apparatus and method of this invention may be modified in order to create a standing curling wave or tubing wave. In one embodiment, an oblique shaped bedform is positioned in the channel at a position where a standing curling wave is desired. This gives the water a sideways velocity component that induces the more downstream side to break continuously while the more upstream side remains an unbroken standing curl. Alternatively, another channel may intersect the end of the primary channel at an oblique angle, with a deeper river flow along the secondary channel. A curling wave is created at the confluence of the faster, primary channel or flume flow and the deeper river flow.
This invention provides a wave generating apparatus and method particularly suitable for use in water park rides and the like which is able to produce more consistent and controllable standing waves than was possible in the past. The waves will be of good quality, enabling surfers to ride for a longer period of time without the wave decaying.
The present invention will be better understood from the following detailed description of some exemplary embodiments of the invention, taken in conjunction with the accompanying drawings in which like reference numerals refer to like parts and in which:
As best illustrated in
The bed forms 15 are each of similar or identical shape and have a leading end 22 and a trailing end 24, with an upstream face 25 inclined upwardly to a peak or upper portion, and a downstream face 26 with a downwardly inclined, convex curvature extending from the peak towards the trailing end 24. As best illustrated in
The weir 12 also extends upwardly from the base, with a trailing end at the inlet from reservoir 14. Spaced inlet side walls 30 extend from a location in reservoir 14 outwardly along opposite sides of weir 12. This has been found to smooth the water flow from the reservoir into the channel 10. The weir 12 is of an airfoil like shape, extending upwardly from the leading edge to a peak and then having a convex downward curvature up to trailing edge 32, which is also spaced above the base 20 of the channel.
In the embodiment of
The weir and bed form may each be supported by pedestals under or adjacent the peak or highest point of the bed form, such as pedestals 42 as illustrated in FIG. 2. Shorter pedestals 44 are provided to support the tail end portion of the weir and bed forms. The pedestals 42 and 44 are adjustable in height, with the opposite sides of the weir and bed forms sliding against the channel side walls 17. In an exemplary embodiment, two spaced pedestals 42 and two spaced pedestals 44 are provided, with each pedestal being approximately one quarter of the bed form width inwardly from the adjacent side wall 17, and spaced apart from the other pedestal by a distance equal to half the bed form width. A greater number of pedestals may be provided if required for additional support.
In order to provide adjustability in the secondary flow, the adjustable pedestals or hydraulic rams 42 and 44 provide height adjusters for varying the bedform and tail elevation. In the illustrated embodiment, the weir and bed forms are each secured to the channel base at the leading end via a first pivot 38, and a trailing end portion of the weir and bed forms is formed as a separate section pivoted to the remainder at a second pivot 40. The first pedestal or hydraulic ram 42 acts between the base of the channel and the upstream pivoted portion of the weir and bed form, and the second pedestal or hydraulic ram 44 acts between the base of the channel and the pivoted trailing end portion of the weir and bed forms. The first height adjuster 42 will change the height of the peak of the weir or bed form, while the second height adjuster will change the elevation of the tail end of the weir or bed form, thus changing the vent height and the amount of secondary flow into or out of the tail end vent. The two pedestals can therefore be adjusted to vary the TEF ratio.
Although the embodiments of
In the apparatus illustrated in
Although the opposite side portions 16 extending from opposite sides of the channel 10 and bed forms out to the outer sides 18 of the wave forming apparatus are shown in
The reservoir 14 will be continuously supplied with water via a suitable water-recirculating system of a type well known in the field of water park rides, in which water leaving the end of channel 10 is pumped back into the reservoir. The water re-circulation path may be beneath the channel 10, around one or both sides of the channel, or from other adjacent, linked rides.
The combination of features in
The weir and bed forms of
The weir 60 is of identical surface shape to the hollow weir 12 of
The bed forms 72 are of similar or identical shape to the bed forms 15 and 52 of the previous embodiments, with a leading edge 75 which has a flush transition with the base 20 of the channel, an upwardly inclined leading face 76, a peak 77, a downwardly inclined, concave trailing face 78, and a re-curved, substantially flat trailing end portion 80 with an abrupt vertical drop off face 82 at the trailing end of the bed form. It has been found that an abrupt drop off, such as vertical face 82 or the trailing end drop offs of
In the embodiments of
In the embodiment of
The bed form 85 has a shape similar to bed form 15 of
In this embodiment, the secondary passageway through the bed form, along with the shallow side portions 16 on opposite sides of the deeper channel containing the bed forms, and the shape of the bed forms, will tend to create a standing wave 104 at the first bed form 85 and each subsequent bed form in the channel, as in the previous embodiments. It will be understood that the weir and bed forms may alternatively be of solid construction with through passageways, as in FIG. 3.
The bed form 120 is of similar shape to the previous embodiments, and has a secondary flow passageway 132 extending from a location adjacent the peak or highest point of the bed form to the trailing end of the bed form, wherein the vent is again covered with a pivoted grating flap 134 permitting height adjustment. An upper portion 135 of the bed form 120 is pivotally mounted at its leading end via pivot 136, and supported at its trailing end by one or more hydraulic rams 138 spaced across the width of the bed form, extending between base 121 and the portion 135. Again, this permits the size of the trailing end vent, and thus the amount of secondary flow in either direction through channel 132, to optimize the standing wave 139.
The passageways 152 are each covered by a safety grating 153 at their open end and communicate with a single through passageway 154 extending through the base of the channel beneath the bed forms. A first portion 155 of the passageway beneath the weir is cut off from the subsequent portion of the passageway extending beneath the bed forms via wall 156. A flow control valve 158 is provided at the junction between each vent passageway 152 and the base passageway 152. This arrangement will also permit standing waves to form by permitting flow into and out of the area beneath the standing wave.
The embodiment of
A series of flap valves 166 are provided across the width of passageway 162 adjacent the trailing end vent opening. This allows the opening size to be varied across the width of the vent 165, to produce various effects in the subsequent standing wave formed downstream of bed form 160. For example, by closing the flaps 166 successively across the width of the vent 165, a sideways breaking wave may be produced. With all the flaps open, a stable standing wave is produced.
It will be understood that other water re-circulation systems may be used, such as passageways around the sides of channel 174, or the outlet end of the wave forming apparatus may be connected to other water rides, and water may then be re-circulated from those rides back to reservoir 170. As in the first embodiment, shallow side portions 185 extend from each side of channel 174 to the outer sides 186 of the apparatus, and this may be inclined slightly upwardly, as in
In this apparatus, as in the previous embodiments, standing waves will be formed downstream of each waveform 176 at the next structure, i.e. the upstream face of the next successive waveform, or, in the case of the last waveform, at the upwardly inclined grafting 178. The formation of a standing wave over grafting 178 has some advantages. For example, after exiting the wave, the rider can easily stand up in the shallow water over the grafting in order to exit the ride. In another alternative embodiment, a wave forming apparatus may comprise a channel as in the previous embodiments with a series of alternating waveforms and graftings, with each wave being formed over a grafting. This will separate the riders more effectively. Each successive waveform and grafting may be stepped down from the preceding pair, to ensure adequate water flow through the channel.
In each of the above embodiments, water flows over and through a weir at the inlet end of the channel. However, flow may alternatively be provided through side channels extending along opposite sides of the weir, under the control of flap valves.
The wave forming apparatus in each of the above embodiments will create a high quality, more readily controlled standing waves. A combination of features produces the optimum wave conditions, with some or all of these features being used dependent on the desired form of the standing wave, and what degree of adjustability in the wave formation is required. One key feature is a sequence of two or more shaped bed forms, such that waves will tend to be formed at a leading face of the successive bed forms. However, this alone is not sufficient to form a stable standing wave. Another key feature in forming a standing wave is the provision of secondary flow beneath each bed form, with a vent for flow into or out of the secondary passageway immediately upstream of the desired wave forming location, prior to the leading face of the next bed form. This is believed to provide flow out of or into the space beneath the wave at the wave forming location, enhancing the stability of the wave.
The opposite end of the secondary passageway is provided in most cases at or adjacent the peak or highest point of the bed form, and may comprise a vent across most of the width of the bed form, or two elongated side vents on opposite sides of the bed form centered at the peak. A further feature which produces improved standing waves is the provision of a sharp, vertical cut off at the trailing end of the bed form, so that a trailing end is spaced above the floor of the channel. This alone, without a secondary passage, will result in some standing wave formation. However, standing waves are enhanced by providing both a secondary passageway and a sharp cut off, as in some of the embodiments illustrated above. The secondary passageway also provides a convenient means for adjusting the standing wave, by means of height adjusters to vary the height of the trailing end of the waveform, valves to vary the secondary flow, and the like, as illustrated in some of the above embodiments. Adjustment of the size of the trailing end vent across the width of the bed form may be used to create a breaking, curling, or pitching wave. A surge of secondary flow can be created by hinging the bed form so as to first cut off the secondary flow, and then lifting the trailing end of the bed form. By providing a flexible trailing end portion for the bed form, which can lift and lower freely based on flow conditions, an oscillating wave form can be produced.
The bed form shape in each of the above embodiments comprises a concave leading face, a curved peak, and a concave trailing face. This tends to produce a wave at the leading face of the next bed form. In some of the above embodiments, the trailing face continues down to blend smoothly with the base of the channel. However, wave forming is enhanced by providing a re-curve adjacent the trailing end of the bed form, to produce a substantially horizontal tail portion before an abrupt vertical drop off at a predetermined tail elevation factor, or TEF, as illustrated in
The flume cross-sectional profile in each of the above embodiments comprises a deeper central channel containing the weir and bed forms for producing waves, and shallower side portions extending outwardly from opposite sides of the channel. This channels the water over the bed forms and prevents too much water from escaping around the bed forms, while allowing the sides of the top portion of each standing wave to vent sideways. This helps to prevent the wave from decaying and enhances stability. The shallow side portions may be tapered slightly upwardly so as to return water back to the center of the channel, although they may alternatively be horizontal or tapered downwardly.
In the previous embodiments, the flume or channel is shown as having a substantially flat or even bed or floor 20. However, it may be beneficial in some cases, particularly in channels with a plurality of bed forms for forming multiple standing waves, for the floor 20 to have a slight incline downwards from the channel or flume entrance to the end of the flume, as illustrated in FIG. 28. This inclination may be in the range of 0 to 4°. Rather than a constant inclination along the length of the flume, it may have a shallower portion extending from the entrance and a steeper portion at the lower end, or it may be curved to provide a change in depth along the flume.
As in the previous embodiments, channel 10 has a weir 12 at its inlet end connected to a supply of water in a reservoir 14. A first bed form 15 is positioned downstream of weir 12 in order to create a stable, standing wave. Oblique bedform 200 is positioned downstream of bedform 15. In alternative arrangements, a greater number of bedforms 15 may be provided prior to oblique bedform 200. The channel 10 is of tapering, gradually increasing width along its length, and may be provided with a water re-circulation system at its end as in
The weir and bed form 15, as well as the oblique bed form 200, are each of hollow shell construction, although they may be of any of the alternative constructions illustrated in the preceding embodiments. The bed forms 15 and 200 each incline upwardly to a peak, and then incline downwardly to a trailing end 24, 202 which is raised above the bed or base 20 of the channel. An inclined grating 204, 205 extends from the trailing end of each bed form down to the base 20. Grating 206 is also provided over the open, trailing end of the weir 12. The bed forms 15 and 200 each have a pair of elongate side vents 34 along opposite sides of the bed form and extending across the peak of the bed form. Similarly, the weir 12 has a pair of elongate side vents 35. The raised trailing end of each bed form and the vents 34 together form a secondary flow passageway for water through the bed form, as described in connection with the previous embodiments.
The oblique bed form 200 in the illustrated embodiment has an oblique or non-perpendicular leading edge 208 and a peak or ridge line 210 which is at the same oblique angle as the leading edge 208. The trailing edge 202 is shown at the same oblique angle as the leading edge and peak, although it may be at a different angle or even perpendicular to the flow. It is the angle of the leading edge and peak which are critical in creating a standing, curling wave or tube, and the orientation of the trailing edge will be dependent on what waveforms, if any, are to be provided downstream of the oblique bed form. It may also be advantageous to rake the trailing edge 24 of the bed form 15 immediately upstream of the oblique bed form 200 to provide the ideal hydraulic conditions for standing wave formation, for example as illustrated in dotted outline in FIG. 18. The angle of the leading edge 208 for creating a curling wave is in the range of 15 to 30 degrees from perpendicular to the flow direction, i.e. 105 to 120 degrees to the flow direction. In the exemplary embodiment, as noted above, the peak or ridge line 210 is at the same angle as leading edge 208, but could vary from this angle in order to create different wave effects.
In this embodiment, the first bed form 15 will create a standing wave with a stable wake as described above, while the oblique bed form will create a stable or standing curling wave. The raked leading edge and slant of the bed form 200 will give water a sideways velocity component which induces the more downstream side to break continuously while the more upstream side remains an unbroken standing wave. Thus, the curling wave will be created near the downstream end of the bed form and will extend across the bed form, as indicated in
All the motion controls applied to the normal standing wave forming apparatus of the previous embodiments may be applied to the oblique bed form for forming the curling standing wave. Thus, the tail elevation, peak height, flow rate, channel depth, and other parameters may be varied in order to vary the wave.
A river bed form 222 is provided in the bed 224 of river or secondary channel 220. River or secondary channel 220 has an inner side wall 229 and an outer wall 230. The river is fed from a suitable water supply such as a reservoir 231. The bed form 222 in river 220 may be a solid or hollow bed form, and does not require any secondary flow channels. The bed form 222 is of generally rounded shape and is elongated in the river flow direction, as indicated in
In this embodiment, a curling wave 232 is created at the confluence of the faster flume flow exiting channel 10 with the deeper and slower river flow along channel 222. A stable wake is induced between bed form 15 and bed form 222. The combination of the stable wake and confluence of the two water flows creates a hollow curling wave suitable for riding in the tube of the wave. This wave can be controlled to advance or recede using the motion controls of the bed form apparatus, as described in detail in the previous embodiments, as well as by changing the flow rates and depths of the primary flume and/or river flow. The two reservoir sources 14 and 231 will provide the proper flow rate and velocity for each flow in order to create the standing, curling wave, and may be adjusted as needed. The curling wave can also be induced to break, advance, and recede by introducing traveling waves into the primary channel or the river flows.
The curling wave 232 is created in part by the depth of the water in the river behind the curling wave, or pooled water level, and partly by the oblique angle of the intersecting flow. Typical hydraulic jumps can be created by introducing faster moving water into slower moving water. The ideal level for the pooled water or intersecting river behind the curling wave 232 is a factor of 1.5 greater than the overall elevation drop from the channel base or flume bottom 20 at the entrance to channel 10 down to the flume bottom at the wave location. Adjusting the pooled water level behind curling wave 232 will change the size and characteristics of the curling wave. If the pooled water level is too high, say a factor of 2 greater than the flume elevation drop, the pooled water may cause the wave to decay. If the pooled water level falls to a factor of 0.7 or less of the flume elevation drop, the wave will be eliminated.
In an exemplary embodiment of the invention, the angle of intersection between the water flows in the primary flume or channel 10 and the river 220 was approximately 75 degrees (i.e. the angle between channel 10 and river 220, but it may be in the range from 30 degrees to 90 degrees. The range of suitable angles depends in part on the velocities of the two flows. For example, two sheet flows (flows with Froude numbers substantially in excess of 5, and approximately 35 and higher in current sheet flow technology practice) can be directed at each other to produce a water effect with the appearance of a curling wave. Any practical angles other than parallel can produce the effect. For standing wave formation, the river flow is typically slower, at subcritical (Froude number less than 1) or faster speeds, producing a hydraulic resistance to the faster flume flow. This, together with the oblique angle of intersection, tends to produce the standing curling wave, with the wave breaking continuously at the downstream end of the intersecting flows and the more upstream end forming an unbroken standing wave. Bed form 222 enhances the standing, curling wave formation. Flume water Froude numbers in the trough just ahead of the standing wave have Froude values in the 1 to 5 range. With standing waves, Froude numbers vary at every location in the flow and are subcritical (less than 1) at the standing wave peak. The river bed form 222 helps to control the position and formation of the standing curling wave.
The jet pump arrangement is illustrated in more detail in FIG. 27. As illustrated, jet pumps 262 will be arranged in pairs inside a housing having a flat upper wall 272, an inclined inlet grille 274, and an inclined outlet grille 275. Water is drawn through the inlet grille and out through the exit grille, as indicated, in order to circulate water at the desired flow rate. The river loop 260 may be elongated if a greater number of standing wave bed forms 15 is desired.
The enhanced, stable, stationary wave formation of this invention, as well as the standing curling wave formation of
Although some exemplary embodiments of the invention have been described above by way of example only, it will be understood by those skilled in the field that modifications may be made to the disclosed embodiments without departing from the scope of the invention, which is defined by the appended claims.
This application is a Continuation-In-Part of application Ser. No. 10/103,600 filed Mar. 19, 2002 now U.S. Pat. No. 6,629,803.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3350724 | Leigh | Nov 1967 | A |
| 3913332 | Forsman | Oct 1975 | A |
| 4954014 | Sauerbier et al. | Sep 1990 | A |
| 5171101 | Sauerbier et al. | Dec 1992 | A |
| 5271692 | Lochtefeld | Dec 1993 | A |
| 5342145 | Cohen | Aug 1994 | A |
| 5421782 | Lochtefeld | Jun 1995 | A |
| 5564859 | Lochtefeld | Oct 1996 | A |
| 5667445 | Lochtefeld | Sep 1997 | A |
| 5913636 | Macaulay | Jun 1999 | A |
| 6019547 | Hill | Feb 2000 | A |
| 6132317 | Lochtefeld | Oct 2000 | A |
| 6336771 | Hill | Jan 2002 | B1 |
| 6460201 | Lochtefeld | Oct 2002 | B1 |
| 6491589 | Lochtefeld | Dec 2002 | B1 |
| 6629803 | McFarland | Oct 2003 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 20030198515 A1 | Oct 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10103600 | Mar 2002 | US |
| Child | 10372549 | US |
