A dual flush water conservation toilet includes separate fill tanks in a toilet tank which pivot to deposit water into a plenum chamber in the toilet tank. The fill tanks are selectively pivoted to deposit different quantities of water for flushing.

BACKGROUND OF THE INVENTION 
     The present invention relates to a water conservation toilet and more particularly to a toilet designed to allow a dual flush alternative. Accordingly the present invention is directed to a toilet which can deliver a first volume of water which is sufficient to empty the contents of the toilet bowl when an individual has urinated in the bowl and a second larger quantity of water sufficient to empty the contents of the bowl when a bowel movement has occurred. 
     In recent years there has been a greater emphasis on conserving natural resources such as water and fossil fuels. Particularly in the water conservation area, especially in commercial buildings such as offices, hotels and apartments, water saving faucets and shower heads have become more and more prevalent in usage as they considerably save the volume of water used through normal activities such as washing and showering. In addition, attempts have been made to provide similar water conservation principals in the use of toilets so that the volume of water used per flush is decreased. Large volumes of water are consumed in a typical toilet when it is flushed. The average flush of a toilet consumes approximately three to five gallons of water and this is far in excess of the amount required for an effective evacuation of the toilet bowl, even when evacuating a bowel movement. 
     It has been recognized in the past that one way to conserve the volume of water used in flushing a toilet is to provide a dual flush alternative where a first limited volume of water is discharged when the toilet has been used only for urination and a second larger volume is discharged when the toilet has been used for a bowel movement. One such prior art device is shown in U.S. Pat. No. 5,067,180 to Figeroid. In this patent the toilet tank is segregated into two compartments each having a flap release valve controlled through a single flush actuating handle. The mechanism is complex and requires the use of two flappers and careful control by the user to initiate either a limited water flush capacity or maximum water flush capacity. 
     A somewhat similar device is shown in U.S. Pat. No. 4,419,772 to Smith which also shows use of a primary and secondary tank area within the water containing tank of a toilet and which is activated by the user according to the needs by controlling the single lever used to flush the tank. 
     Other attempts to address the problem of conserving water in toilet flushing are shown in U.S. Pat. Nos. 5,129,110 to Richter, 5,191,662 to Sharrow, 4,304,014 to Thompson, 5,117,513 to Burrowes, 4,646,369 to Brown et al, 4,561,131 to David, 5,495,624 to Lisook et al, 5,319,809 to Testa, 5,548,850 to Geeham, 5,642,533 to Young, 5,873,136 to Geeham and 5,887,292 to Goren. All of these prior art attempts to provide for a dual capacity flush toilet utilize somewhat complex mechanisms and/or the use of two flap or ball valves to control water egress from the toilet tank to the toilet bowl. These mechanisms, because of their complexity, may also be prone to failure in time and the use of ball or flap valves to control water egress are also prone to failure after a period of time. 
     Accordingly it is an object of the present invention to provide a dual flush capacity water conservation toilet of simple construction with simple mechanism so as to provide a long and useful life without premature failure or need for repair. 
     It is yet another object of the present invention to provide a dual flush capacity toilet of simple construction which can be economically manufactured and which is simple to use. 
     These and other objects and advantages of the present invention will become more readily apparent after consideration of the accompanying specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of a typical toilet; 
     FIG. 2 is a perspective view of a toilet tank for holding water for flushing; 
     FIG. 3 is an exploded isometric showing the mechanism of the present invention; 
     FIG. 4 is a more detailed exploded isometric view of one embodiment of the toilet tank of the present invention; 
     FIG. 5 is a plan view taken along line  5 — 5  of FIG. 3; 
     FIG. 6 a  is a sectional view taken along line  6   a — 6   a  of FIG. 5; 
     FIG. 6 b  is a view similar to FIG. 6 a  showing the mechanism of the present invention in a second position; 
     FIG. 7 a  is a sectional view taken along line  7   a — 7   a  of FIG. 5; 
     FIG. 7 b  is a sectional view similar to FIG. 7 a  showing the mechanism of the present invention in a second position; 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG. 5; 
     FIG. 9 is a sectional view taken along line  9 — 9  of FIG. 5; and 
     FIG. 10 is a view similar to FIG. 4 showing another embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The dual flush capacity mechanism of one embodiment of the present invention may be utilized in a standard toilet tank having a water retention tank  12  and a conventional bowl  14 . As best seen in FIG. 4 the dual flush capacity tank of the present invention includes a first water fill tank or bucket  16  and a second water fill tank or bucket  18 . The first tank  16  has more water capacity than the second tank  18 , as will be explained hereinafter. Preferably, but not essential, tank  16  will have a capacity of 1.0 gallon as this has been found a sufficient quantity of water to effectively evacuate a bowl  14  in which a user has merely urinated. Tank  18  preferably has a capacity of 0.6 gallons which, when combined with the 1.0 gallon retained in tank  16  would deliver 1.6 gallons per flush when both tanks are emptied, and this has been found to be a sufficient quantity of water to effectively evacuate bowl  14  in most instances even when the user has deposited a bowel movement in the toilet. 
     Both fill tanks  16  and  18  are pivotally mounted to tank  12  and pivotally mounted to each other so that the fill tanks  16  and  18  can pivot to discharge the water into the tank. The water is not directly discharged into the tank but is discharged into a plenum chamber  20  which narrows down as in a funnel from a wide open portion  22  which accommodates fill tanks  16  and  18  to a narrower funnel shaped portion  24  and an oval shaped discharge opening  26 . A receiving adapter  27  is provided to fit into the discharge opening  28  of tank  12 . Adapter  27 , preferably of a plastic material, is provided with upwardly and outwardly positioned prongs  29  and downwardly positioned prongs  29 ′. The lower portion of plenum chamber  20  is received within prongs  29  in a snap fit fashion to securely locate and position the plenum chamber within tank  12  and prongs  29 ′ fit within discharge opening  28  to secure the adapter. The end of funnel shaped portion  24  is saw-toothed with a plurality of cutouts  30 , see FIGS. 7 a  and  7   b  as well, to provide a water flow through the bottom of tank  12  to fill the trap line so that odors from the out flow sewage line are contained. The depth of the cutouts  30  will increase or decrease with bowl design to assure minimum required water level above trap entry. 
     A water fill tube  31  is provided which is appropriately connected to an opening  32  in the bottom of tank  12  and tube  31  rises within tank  12 . It terminates in a fill valve assembly  34  having a float control  36  which shuts off the in-flowing water when the water level in both fill tanks  16  and  18  causes float  36  to rise as is conventional in this art. 
     Reference is now made to FIGS. 4,  5 ,  6   a ,  6   b ,  7   a  and  7   b  for a description of the manner in which the two fill tanks  16  and  18  are cooperatively mounted so as to provide a dual flush capacity. The outer end portion  38  of fill tank  16  and the outer end portion  40  of fill tank  18  are each similarly pivotally mounted to the sides of tank  12 . A pivotal mount includes a spindle  42  fixed to a clip  44  by an appropriate bushing  46  and nut  48 . Clip  44  is received through an opening in each fill tank  16  and  18 , in a cutout  50  after the opening to sit in a clip housing  52  within each fill tank  16  and  18 . Spindle  42  is suitably journaled within the end wall of tank  12  to extend outwardly and receive an actuating handle  54 . This is because each fill tank is pivotly mounted within tank  12  and with actuation of handle  54  will cause fill tank  16  and  18  to pivot downwardly from the position shown in FIGS. 6 a  and  7   a  to the position shown in FIGS. 6 b  and  7   b  to empty the contents of the water held in each fill tank into the plenum  20 . The inner end  56  of fill tank  16  and the inner end  58  of fill tank  18  are also pivotly connected to each other. Each end  56  and  58  is provided with a through bore in which is disposed a bushing  60  and  62  which receives a spindle  64  therethrough. 
     As best seen in FIGS. 6 a  and  6   b , as well as in FIG. 4, the exterior surface of the inner end  56  of fill tank  16  and the exterior surface of inner end  58  of fill tank  18  are provided with cam surfaces which, by their position and cooperative relationship, determine which of the fill tanks rotate upon actuation of either the lever  54  connected to fill tank  16  or lever  54  connected to fill tank  18 . The exterior surface of fill tank  16  includes a cam member  66  which is complimentary to and mates with a cam member  68  mounted on the exterior surface  58  of fill tank  18 . Cam surfaces  66  and  68  are preferably in the shape of a half crescent which abutingly mate with each other. 
     With reference to FIGS. 6 a  and  6   b , it is seen that when actuating handle  54  on the left side of fill tank  12  is depressed downwardly in the direction of the arrow, fill tank  16  will rotate to deposit the water contents into plenum  20 . Thus tank  16  will rotate from the position shown in FIG. 6 a  to the position shown in FIG. 6 b  to deposit the water contents of fill tank  16  into the plenum leaving fill tank  18  in a stationary position and without emptying the contents of fill tank  18 . When lever  54  on the right side of tank  12  is depressed, as shown in FIGS. 7 a  and  7   b , cam surface  68  which is positioned in abutting relationship in face-to-face contact with cam surface  66  will cause fill tank  16  to rotate along with fill tank  18  to empty the contents of both fill tanks  16  and  18  into plenum  20 . Thus, rotation of the left handle  54  will result in only fill tank  16  emptying its contents into plenum  20  while rotation of the right handle  54  will rotate fill tank  18  and, by the interaction of the cam surfaces matingly engaging both fill tanks, will also result in rotation of fill tank  16  so that the contents of both fill tanks  16  and  18  will enter into plenum  20  to eventually be discharged through the bowl  14  to complete flushing of the toilet. The trough cutout  70  extending from fill tank  16  also pushes downwardly against the mating trough  72  in fill tank  18  and assists with rotation of the fill tank when handle  54  on fill tank  18  is actuated. 
     To accommodate the selective rotation of fill tank  18  and the selective rotation of both fill tanks and  18  through the rotation of the selected handle  54 , a slightly greater clearance is provided between the inside back wall  69  of tank  12  and the upper lip  71  of fill tank  16  than the clearance between back wall  69  and upper lip  73  of fill tank  18 . This avoids any inadvertent movement of fill tank  16  when only fill tank  18  is moved. This is accomplished by providing an extending lip  71  on fill tank  16  and an extending lip  73  on fill tank  18  with lip  73  being slightly wider than lip  71 . 
     After either fill tank  16  or both fill tanks  16  and  18  have been emptied on a toilet flush, water is allowed to enter through fill valve assembly  34 , as is known in the art. Fill tank  16 , where float control  36  is positioned is filled first and, subsequently, water is directed to fill tank  18  through a trough member  70  attached to the upper end of fill tank  16 . Trough member  70  fits within a trough cutout  72  in the top of fill tank  18  and extends into fill tank  18 . Thus water flows from fill tank  16  into fill tank  18 . Appropriate rubber or plastic seals  74  are provided in trough cut out  72  to prevent leakage of water passing from fill tank  16  into fill tank  18 . The seal is assisted by the pressure applied from the bottom surface of trough  70  acting against the trough  72  and its seals  74 . The pressure comes from the weight of the water in fill tank  16  which is always pressing downwardly due to the fact that the shorter extending lip  71  does not contact the rear wall of plenum  20 . The longer lip  73  extending from fill tank  18  does contact the rear wall of plenum  20 . 
     The dual flush capacity toilet of the present invention works particularly well and is designed to be long lasting without the necessity of changing parts that wear out in time, such as flap valves or ball valves and the lift mechanisms associated with these valve structures. Accordingly, the invention utilizes a plenum chamber  20  which by its shape and design provides a number of beneficial aspects. 
     First, the plenum chamber in this invention enhances the ability to do without a flap or ball valve. Second, by its shape, it initially holds the dumped water up high which then funnels downwardly in a taper, thus providing a pressure head for the water dispensed into the plenum chamber which maximizes the water pressure entering the toilet bowl so that effective cleansing action of the bowl sides and complete evacuation of the bowl contents results. 
     The front wall  76  of plenum chamber  20  is at a much steeper angle to prevent splashing and sloshing of water as fill tanks  16  and  18  empty into the plenum chamber and to encourage more rapid transfer of water through the plenum. 
     Reference is made to FIG. 10 for an alternative embodiment of the present invention where like parts as in the first embodiment are numbered the same. In this embodiment, the fill tank  80  may be a single tank or may comprise the two fill tanks  16  and  18  of the first embodiment. In this case the fill tanks  16  and  18  would be linked together. 
     In this embodiment, the dual flush capacity is obtained by limiting the movement of fill tank  80  when one of the actuating handles are rotated. Thus, for example, the right handle  54  is provided with a rotation stop  46 ′ which limits rotation of right handle  54  and fill tank  80  to approximately 65% of its 90° rotation. Thus only 65% of the contents of fill tank  80  are deposited into plenum chamber  20  to accommodate disposal of only liquid waste. 
     On the other hand, the left handle  54  is allowed to rotate fully so that fill tank  80  rotates a sufficient extent to deposit all of the contents of fill tank  80  into plenum chamber  20  to dispose of solid waste.