CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is related to and claims the benefit of a co-pending U.S. Provisional application Serial No. U.S. 60/406,337, filed on Aug. 28, 2002, the entirety of which is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to a toilet tank flapper which has a short flush and a long flush capability. More particularly, the adjustable flapper uses a moveable weight which, if activated, will temporarily reduce the turning moment arm of the flapper for ensuring a long flush.  
         BACKGROUND OF THE INVENTION  
         [0003]    It is a well known fact that a large use of water in most households, and in many office buildings, is for flushing toilets. Because the flushing is typically carried out with the full capacity of the water in the water tank, the water usage is often wasteful and not required; such as when flushing liquid wastes. For water conservation reasons considerable interest has been centered on designing flushing systems and mechanisms that uses a short duration flush for liquids and a longer duration flush for solids (i.e. a dual-flush toilet).  
           [0004]    Examples of prior art dual-flush mechanisms, which afford a degree of user control over the amount of water used per flush, are U.S. Pat. Nos. 3,935,598, 4,225,987, 4,433,445, 5,129,110, 5,205,000 and 5,524,297. All of the above references, however, lack one or more necessary elements for successful wide utilization in the industry. That is, these prior art references may be prohibitively expensive, too complicated to install, maintain or operate, require the user to hold down the handle for several seconds during the flushing cycle, or may be difficult to retro-fit into existing toilets.  
           [0005]    What is needed is a flushing mechanism or system which will provide a dual-flush capability and which does not have the above-mentioned disadvantages.  
         SUMMARY OF THE INVENTION  
         [0006]    In one embodiment, a pivoting flapper valve assembly, set for a normally short flush, is provided for use in a flush tank. The flapper assembly comprises a weight, which shifts back and forth relative to the assembly&#39;s pivot point. The assembly further comprises an actuator to trap and release the weight, resulting in either a short flush (when the weight is remote from the pivot) or a long flush (when the weight is close to the pivot). The flapper assembly is engageable through a resistance force, for selectively triggering the actuator, shifting the weight and resulting in a long flush.  
           [0007]    More specifically, the assembly includes flush sustaining means preset to maintain the flapper assembly in the open position for a short time (i.e. a short flush). The assembly&#39;s shifting weight, or turning moment arm shifting means, reduces the turning moment arm of the assembly when it shifts closer to the pivot, thereby causing the flush sustaining means to hold the assembly open for a longer time (i.e. long flush).  
           [0008]    In a preferred embodiment, the moment arm shifting means comprises a longitudinal guide mounted for displacement with the assembly, a weight slidably constrained within the guide and retaining means (releasable by the resistance force) to retain the weight at the end of the guide furthest from the assembly&#39;s pivot point. In one embodiment of the invention, the retaining means comprises a magnetic coupling device. In another embodiment, the retaining means comprises a pivoting lever mechanism. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a top view of one embodiment of the invention;  
         [0010]    [0010]FIG. 2 is a side view of the invention according to FIG. 1 shown with the valve assembly in the normally closed position;  
         [0011]    [0011]FIG. 3 is a side view of the invention according to FIG. 1 shown with the valve assembly in a first open position;  
         [0012]    [0012]FIG. 4 is a side view of the invention according to FIG. 1 shown with the valve assembly in a second open position engaging the overflow tube;  
         [0013]    [0013]FIG. 5 is a side view of the invention according to FIG. 1 shown with the valve assembly having returned to the normally closed position;  
         [0014]    [0014]FIG. 6 is a side view of a second embodiment of the invention, with air chamber sustaining means only, and shown with the valve assembly in an open position and engaging the overflow tube;  
         [0015]    [0015]FIG. 7 is a side view of a third embodiment of the invention, with float sustaining means only, and shown with the valve assembly in the normally closed position;  
         [0016]    [0016]FIG. 8 is a top view of a fourth embodiment of the invention;  
         [0017]    [0017]FIG. 9 is a side view of the invention according to FIG. 8 shown with the valve assembly in the normally closed position;  
         [0018]    [0018]FIG. 10 is a side view of the invention according to FIG. 8 shown with the valve assembly in a first open position;  
         [0019]    [0019]FIG. 11 is a side view of the invention according to FIG. 8 shown with the valve assembly in a second open position engaging the overflow tube;  
         [0020]    [0020]FIG. 12 is a side view of the invention according to FIG. 8 shown with the valve assembly returning to the normally closed position;  
         [0021]    [0021]FIG. 13 a  is a side view of one model of flush valve having a generally horizontal outlet; and  
         [0022]    [0022]FIG. 13 b  is a side view of another model of flush valve having an angled outlet. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    With reference to FIGS.  1 - 5 , in a first embodiment, a flapper valve assembly  1  is adapted with turning moment arm shifting means  2 . A substantially conventional flapper or flapper valve  3  is attached to a flush tube or overflow tube or pipe  4  of a toilet tank (not shown). Two arms  3   a , functioning as an attachment means, extending from the flapper  3  are anchored at hangers or pivots  5  on the overflow pipe  4 . The flapper  3  rotates about the pivots  5  in plane D between a lower closed position, seating on an outlet  4   b , and an upper open position, suspended above the outlet  4   b.    
         [0024]    Simply, the turning moment shifting means  2  is adapted to a flapper valve  3  for varying its rate of closing during a flush. The shifting means  2  comprises a weight  6  which can shift along a guide  7  and further incorporates a valve operating mechanism  8  for opening the valve  3 . Coordinated with the operating mechanism  8  is a weight retaining means or latch  9  for determining whether the weight  6  shifts or not.  
         [0025]    Normally, the weight  6  resides over the flapper  3 , furthest from the pivot  5  for imposing maximal turning moment to close the flapper  3  and ensuing a short flush. Through a further activating action, the weight  6  can be enabled to shift closer to the pivot  5  for minimizing the turning moment, lessening the impetus to close the flapper  3  and ensuing a longer flush. Once flushed, the weight  6  shifts back to reset the latch  9  so as to again be retained over the flapper  3 , for a short flush, until activated once again.  
         [0026]    As shown in FIG. 2, the assembly  1  is normally closed; with the flapper  3  sealed to the outlet  4   b , and wherein the tank is ready to flush. The assembly  1  is activated or opened by the valve operating mechanism  8  which raises the flapper  3  with a chain or other suitable tensile connector  10 , causing the flapper  3  to rotate about the pivots  5 . Typically, the valve operating mechanism  8  includes a flush handle (not shown) connected to a lift arm (not shown) which in turn is connected to the chain  10 ; the other end of the chain  10  being attached to the assembly  1 .  
         [0027]    To prevent the flapper  3  from prematurely closing and sealing the outlet  4   b , flush sustaining means  11  are provided to counteract the flapper&#39;s natural tendency to close and thereby maintain the assembly  1  in the open position for a predetermined amount of time. The sustaining means  11  could include a traditional air chamber  3   b  and release hole  3   d  incorporated in the flapper  3 , a float  12  attached to the chain  10 , or a combination thereof. Depending on the composition of the flapper  3  or assembly  1 , the sustaining means  11  could also consist of solely the inherent buoyancy in such a flapper or assembly. When there is no reduction in the moment arm of the assembly  1 , the sustaining means  11  keep the assembly  1  in the open position for a predetermined time which is less than the time needed to substantially drain the tank, resulting in a short flush.  
         [0028]    In this embodiment, FIGS.  2 - 5 , the sustaining means  11  is illustrated as the combination of air chamber  3   b  and float  12 , although other configurations are also suitable (e.g. FIG. 6 with air chamber  3   b  only, or FIG. 7 with float  12  only). The air chamber  3   b  has an opening  3   c  through the bottom and a release hole  3   d  of predetermined size. Further in this embodiment, the float  12  is adjustably attached to the chain  10  by means of a length of beads  10   b  of conventional design. As shown in FIG. 3, during a flush operation, with the flapper  3  inclined, air escapes through the release hole  3   d  at a predetermined rate, reducing the buoyancy of the flapper  3 , while the float  12  provides additional buoyancy until the water drops to the level of the float  12 . The combination of buoyant flapper  3 , and float  12  cause the assembly  1  to close after the predetermined time. Adjusting the float  12  along the bead chain  10   b  will adjust the length of the predetermined amount of time.  
         [0029]    For enabling actuating distinction between a short flush and a long flush, means are provided for limiting the upward rotation of the assembly  1 . For instance, a protrusion or stop  13  is formed on the flapper  3  adjacent the overflow pipe  4 . As shown in FIG. 4, when the flapper  3  is rotated about the pivots  5  to an extreme upward or open position, the stop  13  contacts the overflow pipe  4 , creating a resistance force at point E and limiting any further opening. In alternate embodiments, with flappers lacking a discrete stop  13 , that portion of the flapper  3  which first contacts the overflow pipe  4  acts as the stop  13 .  
         [0030]    Generally, in the embodiment of FIGS.  1 - 5 , the weight  6  moves back and forth to shift the turning moment of the flapper  3 . The turning moment arm shifting means  2  comprises a longitudinal guide or sleeve  7 . The weight  6  is moveably constrained within the sleeve  7  along axis C. The shifting means  2  further comprises a latch  9  such as magnetic coupling device  14 ,  15  to control movement of the weight  6 . Note that other configurations of a weight  6  and guide  7  are possible and that the weight need not be constrained within the guide  7  as long as the weight  6  is constrained for movement along the guide  7 . For example, a weight could be fitted around a guide.  
         [0031]    The sleeve  7  has first and second ends  7   a ,  7   b , mounted for displacement with the assembly  1  and axially aligned substantially parallel to the flapper  3 . The first end  7   a  is further from the pivot point  5  than the second end  7   b  and, when the assembly  1  is in the lower closed position, the first end  7   a  is slightly lower than the second end  7   b  so that the weight  6  can move to the first end  7   a  and reset. The sleeve  7  is angled laterally relative to the longitudinal axis of the assembly  1  (FIG. 1) so as to permit the sleeve  7  to be relatively long, more closely approaching the pivot  5 , for maximum variation in the shifting of the weight  6  while still avoiding contact with the overflow tube  4 . When the assembly  1  is closed, the moveable weight  6  shifts towards the lower first end  7   a  due to gravity pulling the weight  6  in direction C″ (FIG. 5).  
         [0032]    Referring to FIGS. 3 and 4, in order to allow a user to decide between a short or long flush, a latch  9  having a short flush and a long flush position is provided to alternatively keep the weight  6  positioned near the first end  7   a , or to allow the weight  6  to shift to the second end  7   b . The latch  9 , or magnetic coupling device  14 ,  15  in one embodiment, is shown as a first magnetic coupler or magnet  14  attached to the end of the chain  10  and a corresponding magnetically affected material of a second magnetic coupler or magnet  15  is associated with the weight  6 . Other constructions of magnet, magnets, magnetic couplers or complementary materials are equivalent, referred to herein simply as magnets  14 ,  15 . The magnet  14  is enclosed in a chamber  7   c , at the sleeve&#39;s first end  7   a , so that it is limited to a small movement or displacement along axis B, but such displacement when so activated is sufficient to break the magnetic attraction between the magnets  14  and  15 . Therefore, the magnets  14 ,  15  act as a biasing means to maintain the latch  9  in the short flush position and the chamber  7   c  acts as a displacement limiting means to limit magnet  14  to a small movement along axis B.  
         [0033]    As shown in FIG. 3, the magnetic attraction between the magnets  14 ,  15  in turn is sufficiently strong to keep the weight  6  at the sleeve&#39;s first end  7   a  and allow for a first tension in the chain  10  and a tensile force in direction A′ to be transmitted from the chain  10  to the assembly  1  (via weight  6  and sleeve  7 ), until the assembly  1  encounters a sufficient resistance force. If little resistance force is encountered then the assembly  1  merely pivots upward in plane D, opening the flapper valve  3 , causing the flushing process to begin until the sustaining means allows the valve  3  to close after the predetermined amount of time. Alternately, a larger and second tension results and a sufficient resistance force for a long flush is created when the upward rotation of the assembly  1  in plane D is limited by the stop  13  contacting the tube  4  at point E.  
         [0034]    Alternatively, a sufficient resistance force is created when the chain  10  is raised faster than normal (e.g. a quick, vigorous lift) and the inertia of the assembly  1  and the resistance to movement retards the assembly&#39;s motion.  
         [0035]    Referring again to FIG. 4, the stop  13  is shown engaging the overflow tube  4  at point E. The rotation of the assembly  1  in direction D is stopped. Continued pulling and increased second tension in the chain  10  creates a resistance force at point E, which is transmitted through the assembly  1  and is sufficient to release the magnet coupling device  14 ,  15  free of the weight  6 . Once the magnetic attraction is broken between magnets  14 ,  15 , and with the guide inclined, the weight  6  is freed to slide in direction C′ to the sleeve&#39;s second end  7   b ; the second end  7   b  now being lower than the first end  7   a  by virtue of the assembly  1  having pivoted in direction D′. The movement of the weight  6  moves the center of gravity of the assembly  1  towards the pivot  5  and the turning moment arm about the pivots  5  is thereby reduced. The reduction of the assembly&#39;s turning moment arm allows the sustaining means  11  to keep the flapper  3  open for a time longer than the predetermined time, resulting in a larger discharge of water into the toilet bowl.  
         [0036]    Further Embodiment:  
         [0037]    Now with reference to FIGS.  8 - 12 , in another embodiment, the flush valve assembly  1  is again provided with the turning moment arm shifting means  2 . However, the weight  6  is retained or biased at the sleeve&#39;s first end  7   a , not by a magnetic coupling latch, but by a pivoting lever mechanism  20  or latch  9 .  
         [0038]    With reference to FIG. 8, the pivoting lever mechanism  20  comprises a lever  21  with a stop  22  depending downward from it at an acute angle. One end of the lever  21  is attached to the upper portion of the sleeve  7 , near the first end  7   a , at point  23 . The other end of the lever  21  features a slot  24  through which the chain  10  is positioned and constrained (FIG. 8). Although shown comprising a lever  21  with a stop  22  depending down at an acute angle, the pivoting level mechanism  20  could incorporate levers of a different design or which are mounted at a different pivot point.  
         [0039]    The stop  22  extends from the lever  21  at the pivot point  23  and projects into the interior of the sleeve  7 . The stop  22  engages the weight  6  and functions to retain or bias the weight  6  at end  7   a . A tab  25 , which is larger than the width of the slot  24 , is positioned on the chain  10  just below the lever&#39;s slot  24 . Finally, a lever reset spring  26  is attached between the chain  10  and the flapper  3 . In this embodiment the weight  6  is shaped as a ball for rolling movement, but other shapes are possible.  
         [0040]    Turning to FIG. 10, the tension in the spring  26  is sufficiently strong to allow for a tensile force in direction A′ to be transmitted from the chain  10  to the flapper  3  retaining the weight  6  until the assembly  1  encounters a sufficient resistance force. A sufficient resistance force is created when the upward rotation of the assembly  1  in plane D is limited. Alternatively, a sufficient resistance force is created when the chain  10  is raised faster than normal and the inertia of the water in the tank acts on the assembly  1 . Therefore, the pivoting lever mechanism  20  and spring  26  act as a biasing means to maintain the latch  9  in the short flush position.  
         [0041]    Referring now to FIG. 11, the stop  13  is shown engaging the overflow tube  4  at point E. The rotation of the assembly  1  in direction D′ is stopped. Continued pulling of the chain  10  creates a resistance force at point E, which is transmitted through the assembly  1  and is sufficient overcome the spring  26  thereby lengthening it. Once the spring  26  lengthens (F′), the tab  25  acts on the lever  21 ,  24  and pivots the lever  21  in direction G′. As the lever  21  pivots, the stop  22  disengages from the weight  6  and allow the weight  6  to move in direction C′ to the sleeve&#39;s second end  7   b . The second end  7   b  is now lower than the first end  7   a , by virtue of the assembly  1  having pivoted in direction D, and gravity pulls the weight  6  to the second end  7   b . The movement of the weight  6  moves the center of gravity of the assembly  1  and the turning moment arm about the pivots  5  is thereby reduced, keeping the flapper  3  open for a time longer than the predetermined time and resulting in a larger discharge of water into the toilet bowl.  
         [0042]    Referring to FIG. 12, the assembly  1  is shown returning to the normal position; with the flapper  3  closing the outlet  4   b . As the chain  10  is lowered in direction A″ the resistance force is gone and the spring  26  contracts back to its normal size in direction F″. The sleeve&#39;s first end  7   a  is once again lower than the second end  7   b , and gravity causes the weight  6  move down to the first end  7   a . As the weight  6  shifts back to the first end  7   a  it engages the stop  22 , bumping the stop  22  and the lever  21  up to allow the weight  6  to pass. The lever  21 , guided by the chain  10  constrained in the slot  24 , simply pivots up in direction G′ until the weight is past the stop  22 ; at which point gravity pulls the lever  21  down, thereby re-engaging the stop  22  with the weight  6  so as to retain the weight  6  at the first end  7   a . In this way, the shifting means  2  is reset, ready to be activated by the next sufficient resistance force, to reduce the assembly&#39;s  1  turning moment arm once again.  
         [0043]    Summary of Operation:  
         [0044]    Referring generally to FIGS. 3,4,  10  and  11 , through a conventional flush handle or other operating mechanism, the user operates the assembly  1  in the conventional way by exerting a lifting tensile force (A′) on the assembly  1  through the chain  10 , causing the assembly  1  to rotate about the pivots  5 . For instance, one known flush handle from Korea is a dual-flush handle which uses a downward rotation of the handle to result in a short chain lift and an upward rotation of the handle to result in a long chain lift.  
         [0045]    For a short flush, a short chain lift opens the flapper  3  and does not encounter sufficient resistance to activate the weight shifting means  2  and the assembly&#39;s turning moment arm remains maximal and unchanged. The sustaining means  11  keeps the assembly  1  open for a short flush.  
         [0046]    For a long flush, a long chain lift rotates the flapper  3  until it is stopped, resulting in sufficient resistance force to activate the shifting means  2 , releasing the weight  6  to move closer to the pivot  5 , minimizing the assembly&#39;s turning moment arm. With a reduced turning moment arm, the sustaining means  11  is able to keep the assembly  1  open for a longer time; resulting in a long flush.  
         [0047]    As shown in FIG. 13, the flapper outlet  4   b  can be horizontal or on an angle without effecting the nature of the invention.
A dual-flush flapper valve assembly, set for a normally short flush, is provided for use with a pivoting flapper valve in a flush tank. The assembly comprises a weight, which moves back and forth along a guide relative to the flapper's pivot point. The moveable weight, if activated, temporarily reduces the turning moment arm of the flapper for ensuring a long flush. The assembly further comprises an actuator to trap and release the weight, resulting in either a short flush (when the weight is remote from the pivot) or a long flush (when the weight is close to the pivot). The flapper assembly is engageable through a resistance force, for selectively triggering the actuator, shifting the weight and resulting in a long flush. After a long flush the assembly resets for a short flush, until activated once again.