You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a Continuation of U.S. patent application Ser. No. 11/800,723 filed May 7, 2007, which has issued as U.S. Pat. No. 8,151,379. U.S. patent application Ser. No. 11/800,723 is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    This invention relates generally to toilets that can remove waste from a toilet bowl efficiently with small amounts of water. 
         [0003]    Water shortages are serious problems in many regions. This had led to government regulation regarding water use efficiency of certain products. For example, some jurisdictions regulate the maximum amount of water used by a toilet during a flush. While usage of as much as 7 gallons per flush was conventional in the early 1950s, current regulations in some jurisdictions require that no more than 1.6 gallons of water be used per flush. There are proposals to reduce the permitted usage further (e.g., to 1.2 gallons/flush). 
         [0004]    Even when there is no governmental requirement restricting water usage, environmentally conscious consumers often prefer low water usage toilets. Moreover, water utilities are significantly increasing the cost of water supply, providing yet another motivation for consumers to prefer low water usage toilets. 
         [0005]    As water usage per flush cycle is reduced, it is important that cleaning efficiency remain at acceptable levels. If cleaning efficiency is compromised, the consumer will in some situations be led to flush a second time, frustrating the regulatory, conservation, and cost savings goals. 
         [0006]    Complicating matters is that in addition to cleaning the bowl sides, the flush water has other functions. It is typically used to form a gravity siphon which helps move the waste out of the bowl. Also, the water is needed to rinse the bowl once the main waste has been dislodged and evacuated. Further, water is needed to re-establish an odor seal in the trap. Also, water needs to be available to clean the entire circumference of the bowl. These additional requirements complicate the design of low water usage toilets. 
         [0007]    One way to improve the efficiency of cleaning is to pressurize the cleaning supply of water. However, this can unacceptably increase the cost of the toilet. 
         [0008]    Another approach is to split the rim flow into two unequal branches. See, for example, U.S. Pat. Nos. 4,930,167 and 6,397,405. However, prior systems of this type could have evacuation issues at low water usage rates. 
         [0009]    Another approach is to use a tapered passage at the bottom of the bowl near the bowl outlet (which generally is referred to as a “jet”) to more efficiently start the siphon out of the bowl. See, for example, U.S. Pat. Nos. 5,218,726, 5,283,913 and 6,145,138. However, achieving adequate cleaning along the sides of the bowl is difficult with low water usage when a substantial portion of the water has been diverted for jet use. 
         [0010]    Yet another approach is to use a multi-loop vortex flow approach. See, for example, U.S. Patent Application Publication No. 2004/0040080. This takes energy out of the water before it reaches the siphon trap, which could be problematic. 
         [0011]    In U.S. Patent Application Publication No. 2003/0115664 there was a toilet disclosed with some rim flow along a right branch, some rim flow along a left branch, and some flow down and straight ahead. However, this design had certain inefficiencies which constrained the reduction in water usage. For example, water entered at a right angle to the rim, thereby dissipating cleaning energy. Further, some water was used in an opposing manner. 
         [0012]    It is therefore desired to develop further improved toilets to reduce water usage without undesirably compromising cleaning or other water closet performance characteristics. 
       SUMMARY 
       [0013]    An exemplary embodiment relates to a toilet which has a bowl having an upper rim channel and a water distribution structure for delivering water from a water supply to the bowl. The water distribution structure has an entry suitable to link with the water supply (e.g., a toilet tank or Flushometer type supply) and at least three exit channels. 
         [0014]    A first of the exit channels communicates with the rim channel so as to provide at least counter clockwise flow around a first side of the rim channel. A second of the exit channels communicates with the rim channel so as to provide at least clockwise flow around an opposed side of the rim channel from the first side of the rim channel. A third of the exit channels communicates with a rearward portion of the rim channel. 
         [0015]    The rim channel has a first enlarged opening to the bowl adjacent a rearward portion of the bowl, and a second enlarged opening to the bowl adjacent a forward portion of the bowl. The water distribution structure is configured so that when water is delivered to the rim channel a vortex of water will be developed in the bowl. 
         [0016]    In an exemplary embodiment, the third exit channel is configured to feed water to the rim channel at an angle relative to the rim channel. Also, the first exit channel is suitable to carry a greater volume of water than the second exit channel (e.g., its cross sectional area is greater), and the first and second exit channels are each suitable to carry greater volumes of water than the third exit channel. 
         [0017]    In another exemplary embodiment, the toilet bowl has a forward-to-back vertical central plane. The first and third exit channels link with the rim channel on one side of the vertical central plane and the second exit channel links with the rim channel on an opposite side of the vertical central plane. 
         [0018]    In yet another exemplary embodiment, the first and second enlarged openings each have a central point on the same side of the vertical central plane, the bowl is provided with an integral rearward extension, the water distributor is integrally formed along the rearward extension, and the rim channel is an open rim style rim channel in which a gap between sides of the rim channel is varied to form the enlarged openings. 
         [0019]    With this embodiment, entering water from the tank or other supply is thus split into three flows. One flow directly enters the bowl near its rear from the rim channel. Another flow, the primary flow, joins that first flow in part and in addition serves two other functions. One function is to wash one side of the bowl. Another is to pass almost to the front of the bowl and then enter the bowl in a large stream. Yet another flow is primarily to wash the opposite side of the bowl, albeit most preferably it also assists in washing the upper rear of the bowl. 
         [0020]    The water enters the rim channels at an angle so as to keep the energy of the water largely intact. Surprisingly, the flow from the essentially forward (e.g., one o&#39;clock or alternatively 11 o&#39;clock) position avoids the need for a jet, thereby permitting all flow to enter from the rim channel in the exemplary embodiments. 
         [0021]    Another exemplary embodiment relates to a toilet having a bowl with an upper rim channel, and a water distribution structure for delivering water from a water supply to the bowl. The water distribution structure has an entry suitable to link with the water supply and at least two exit channels. 
         [0022]    A first of the exit channels communicates with the rim channel so as to provide both a counter clockwise flow and a clockwise flow around a first side of the rim channel if water is supplied to the toilet. There is also a second of the exit channels which communicates with the rim channel so as to provide a flow pattern selected from the group consisting of clockwise flow and counter clockwise flow around an opposed side of the rim channel from the first side of the rim channel if water is supplied to the toilet. 
         [0023]    The rim channel has a first enlarged opening to the bowl adjacent a rearward portion of the bowl, and a second enlarged opening to the bowl adjacent a forward portion of the bowl. The water distribution structure is configured so that if water is delivered to the rim channel a vortex of water will be developed in the bowl. 
         [0024]    Regardless of the aspect of the invention applied, as a result, with less water usage, effective cleaning can be achieved. The water is used in a way to also facilitate rinsing, evacuation and re-seal. 
         [0025]    Current tests indicate that effective cleaning can be achieved at 1.6 gallons per flush, and further indicate that these toilets may provide effective cleaning with even lower levels of water use per flush. Such toilets can be manufactured using conventional molding techniques, without significant additional costs above those experienced with conventional cast toilets. 
         [0026]    These and still other advantages of the present invention will become more apparent, and the invention will be better understood, by reference to the following description of preferred embodiments of the present invention which follows (with reference to the accompanying drawings). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  is an exploded perspective view of a toilet according to an exemplary embodiment. 
           [0028]      FIG. 2  is a lower, left fragmentary perspective view of a portion of the toilet of  FIG. 1 . 
           [0029]      FIG. 3  is a lower, right fragmentary perspective view of the toilet of  FIG. 1 . 
           [0030]      FIG. 4A  is a top view of the toilet of  FIG. 1 , without the water tank, at the initiation of a flush cycle. 
           [0031]      FIG. 4B  is a view similar to that of  4 A, but with the flush progressing into a cleaning vortex. 
           [0032]      FIG. 5  is a cross-sectional view taken along section line  5 - 5  in  FIG. 1 . 
           [0033]      FIG. 6  is a cross-sectional view taken along section line  6 - 6  in  FIG. 4A . 
           [0034]      FIG. 7  is a cross-sectional view taken along section line  7 - 7  in  FIG. 4A . 
           [0035]      FIG. 8  is a cross-sectional view taken along section line  8 - 8  in  FIG. 4A . 
           [0036]      FIG. 9  is a cross-sectional view taken along section line  9 - 9  in  FIG. 4A . 
           [0037]      FIG. 10  is a cross-sectional view of another exemplary embodiment of a toilet, which is similar to  FIG. 5 , but instead illustrates a holed rim structure instead of an open rim design. 
           [0038]      FIG. 11  is a top view of yet another exemplary embodiment of a toilet. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    With general reference to the Figures, and more particularly to  FIGS. 1 ,  4 A,  4 B and  5 , there is shown a toilet  20  which includes a bowl  22  with a rim  24  at an upper extent  26  of bowl  22 . The rim  24  has a rim channel  28  therein. The bowl  22  can be conceptually considered to have a central vertical plane  30 . 
         [0040]    There is a water tank  32 , which may have the usual internal flush valve, a flush actuator and other fittings as are required (not shown). Alternatively, toilet  10  can be a tankless design which is directly connected to line water pressure via a Flushometer type valve (also not shown). The bowl  22  discharges into a trap and drain line (also not shown). 
         [0041]    A rear extension  34  can extend from rim  24 . It includes a water distributor structure  36  which is in communication with both the water supply and three exit channels  38 ,  40  and  42 . The exit channels in turn are in fluid communication with the rim channel  28 . The channels  38 ,  40 ,  42  extend at corresponding angles  46 ,  48 ,  50  respectively. Each of the channels  38 ,  40 ,  42  are nonparallel with the vertical central plane  30 . 
         [0042]    The angle  46  is greater than the angle  48 , and the angle  50  is greater than the angle  48 , for optimal vortex formation. The channel  38  and the channel  40  are on the same side of the vertical central plane  30  as each other, and the channel  42  is on an opposite side. 
         [0043]    While three exit channels are preferred, it should be appreciated that to address particular concerns with particular style toilets one or more additional exit channels may be also used. Further, where one of the exit channels provides both clockwise and counter clockwise flow due to its angle of entry and positioning, in some cases only two exit channels need be used. 
         [0044]    In any event, in our preferred embodiment, the channel  38  has a larger cross-sectional area  52  than the channel  40  with its cross-sectional area  54 , or that of channel  42  and its cross-sectional area  56 . The cross-sectional area  56  is in turn preferably larger than cross-sectional area  54 . These further facilitate vortex formation, as well as help facilitate evacuation of the bowl. For example, the channel  38  could take 33% to 45% of the total flow, the channel  42  could take 27% to 39% of the total flow, and the channel  40  could take 21% to 33% of the total flow. 
         [0045]    The rim  24  of the toilet  20  has gaps  58 ,  59 ,  60 ,  61  ( FIGS. 5-9 ) which allow the flush water to exit continuously from the rim channel  28  into the bowl  22 , albeit at different rates at different places depending on the gap&#39;s size. Two distinct sections of the larger gaps  60 ,  61  in the rim  24  designates a first biasing flow aperture/enlarged opening  62  having a first center  64  and a second biasing flow aperture/enlarged opening  66  having a second center  68 . The center  68  is preferably −30 degrees to +30 degrees from straight forward, and the center  64  is preferably −30 degrees to +30 degrees from rear. 
         [0046]    The orientation and design of biasing flow apertures/enlarged openings  62 ,  66 , in conjunction with the orientation and design of the channels  38 ,  40 ,  42 , create first biasing flow  70  and second biasing flow  72 , which merge in the vicinity of the sump area  74 . This merging/collision, along with the other rim wash  76  emanating from secondary flow apertures  77 , develops into a vortex flow  78  which exits toilet  20  through an outlet  80  in the sump area  74 , overcomes the verge of the toilet trap, helps creates a siphon discharging the contents of the bowl  22  into the trap and sewer line, and then recreates the bowl seal. 
         [0047]    The center  64  and center  68  are in this embodiment on a same side of the vertical central plane  30 . The bowl  22  has a water inlet side  82 , and a forward side  84  opposite water inlet side  82 , where the first biasing flow aperture/enlarged opening  62  can be on water inlet side  82 , and second biasing flow aperture/enlarged opening  66  can be on the forward side  84 . 
         [0048]    The gap  58  can be the same or different than the gap  59 . Similarly, the gap  60  can be the same or different than the gap  61 . The gaps  60 ,  61  are larger than the gaps  58 ,  59 . 
         [0049]    Note that the narrowing of the gaps  58  and  59  relative to the gap  60  serves a number of functions. For one thing, it permits more of the water from the channel  38  to reach the enlarged opening  66 , while still permitting some water to flow down the bowl sides near  77 . 
         [0050]    For another, it helps deliver the water to a rim tapering area  90  in sufficient amounts that the water speed is accelerated as it is delivered to the opening  66 . This added boost further assists in evacuation and vortex formation. 
         [0051]    It should also be noted that water coming out of the channel  42  primarily flows clockwise as shown by the arrow  91 . However, there is also a secondary flow  92  counter clockwise to help clean the rear portion of the upper bowl. This is important because the channel  40  is angled away from that region of the bowl to preserve the energy of the water. 
         [0052]    The toilet  20  can include mounting holes  86 ,  87  for respectively mounting the water tank  32  and a toilet seat (not shown), and a tank inlet hole  88  for providing access for the water tank  32  water inlet (not shown). 
         [0053]    The embodiment of the toilet  20  illustrated in  FIGS. 1-9  has a rim channel  28  that discharges through a continuous gap, an “open rim” type design. However, the present invention can also be applied to other types of rim channels. For example,  FIG. 10  illustrates a toilet  90  which has a rim channel  93  wherein the first biasing flow aperture comprises a first water delivery slot  94  along an underside of the rim, and the second biasing flow aperture comprises a second water delivery slot  96  along the underside of the rim. The secondary flow apertures comprise at least one additional water delivery hole  98  in the rim each smaller than first water delivery hole  94  and/or second water delivery hole  96 . Other aspects of the toilet  90  are the same or similar to the toilet  20 . 
         [0054]    Although the embodiments of  FIGS. 1-10  illustrate a counterclockwise vortex flow, the present invention can be adapted for clockwise flow as illustrated in  FIG. 11 . In this regard, the toilet  100  has the channels  38 ,  40 ,  42 , which have been placed on the respective other side of the vertical central plane  30  when compared to the placement in the toilet  20 . Similarly, although not shown, the first biasing flow aperture and the second biasing flow aperture are placed on the respective other side of the vertical central plane  30  when compared to the corresponding placement in the toilet  20 , to produce first biasing flow  102  and second biasing flow  104 , which results a clockwise vortex flow  106 . This arrangement can be applied to the open rim arrangement of the toilet  20  or the hole arrangement of the toilet  90 , or some combination thereof. 
         [0055]    Further, it should be noted that while flow has been described in the rim channel with reference to both clockwise and counter clockwise flow, it is highly desirable that these mixed direction flows quickly result in a one direction vortex. Hence, for flow out of the channel  42  it is desirable for most of the clockwise energy to be out of the water when it starts dropping along the bowl sides. This can be achieved by elongating channel  42  relative to the channel  38 , and also by widening the rim channel from 6 o&#39;clock to 12 o&#39;clock. 
         [0056]    We also prefer to have embodiments where when the flush cycle starts the first water enters from the channel  38  as compared to the channel  42 . This further facilitates vortex formation. We achieve this by having the channel  38  longer than the channel  42 . 
         [0057]    Therefore, the present invention is not to be limited to just the described most preferred embodiments. Rather, in order to ascertain the full scope of the invention, the claims which follow should be referenced. 
       INDUSTRIAL APPLICABILITY 
       [0058]    The present invention provides a toilet with reduced water usage while retaining effective cleaning and other performance.

Summary:
A toilet, comprising a bowl, a rim provided at an upper portion of the bowl, a rim channel disposed in the rim, a rear extension that extends from the rim, and a water distribution structure provided in the rear extension and configured to receive water from a water supply. The rim channel includes a first opening, a second opening, and a third opening located between the first and second openings, the openings being configured to communicate water to the bowl. The water distribution structure having at least two exit channels configured to communicate water to at least two different locations of the rim channel.