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CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/892,781 filed Mar. 2, 2007, which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD OF THE DISCLOSURE  
       [0002]    The present disclosure relates to fill valves for use in toilet tanks and, more particularly, to a mechanism for preventing leakage of water from a toilet tank between flush cycles. 
       BACKGROUND OF THE DISCLOSURE  
       [0003]    Referring to  FIG. 1 , most toilet tanks include a float movable with the water level in the tank during flush cycles to operate a fill valve to refill the tank upon lowering of the water from a predetermined level and to close the fill valve once the tank is refilled to the predetermined level. During flush cycles, operation of a flush lever unseats a flush valve in the tank causing the water in the tank to be released through a discharge opening, and the float descends in response to lowering of the water level from the predetermined level, causing opening of the fill valve to refill the tank with closure of the flush valve. As the toilet tank is refilled, the float ascends in response to rising of the water level and, when the water level returns to the predetermined level, the float operates to close the fill valve and prevent further supply of water to the toilet tank. 
         [0004]    A problem exists where the water level in the tank drops from the predetermined water level not due to flushing but due to leakage, typically through the flush valve, between flush cycles in that the float operates to open the fill valve allowing water to flow into the tank to replace that lost through leakage. During leakage, the float operates to keep the fill valve open such that water continually flows into the tank and through the discharge opening. On a small scale, this type of leakage is difficult to detect audibly and visually, such that the leakage problem can remain undetected and lead to wasted water. On a larger scale, the leakage can lead to flooding and property damage as well. 
         [0005]    In many cases, consumers are alerted to major, continual leakage only through drastically high water utility bills while insidious or sporadic leakage can remain unrecognized with consumers inadvertently absorbing inflated water utility costs from the leakage. In addition to a direct economic burden on consumers, the aggregate effect of water leakage through deficient flush valves of toilet tanks is the waste of untold gallons of water, an increasingly scarce resource. 
         [0006]    What is still desired is a new and improved mechanism for preventing leakage from a tank of a toilet. The mechanism will preferably prevent operation of a fill valve of the toilet unless and until a handle of the toilet is purposely operated to initiate a flush cycle. 
       SUMMARY OF THE DISCLOSURE  
       [0007]    The present disclosure provides a toilet fill valve that includes a mechanism for preventing leakage from a tank of the toilet between flush cycles. The mechanism includes links that are normally locked to prevent the fill valve from opening. The links are operatively connected to a handle of the toilet such that the links are unlocked and allow the fill valve to open only when the handle of the toilet is purposely operated to initiate a flush cycle. Otherwise, the links do not allow the fill valve to open even if water leaks from the tank and causes a float of the fill valve to be lowered. 
         [0008]    According to one aspect of the present disclosure, the leakage prevention mechanism can be manually disabled. 
         [0009]    One embodiment of the present disclosure is directed to a fill valve assembly having a valve for controlling water flow into the toilet tank and a valve member coupled to the valve for movement between an open position that admits water through the valve and a closed position that closes the valve. A first locking link pivotally couples to the valve member and a second locking link pivotally couples to the first locking link. A valve reset lever pivotally connects to the second link and a float linkage pivotally connects to the valve reset lever. A buoyant float is secured to the float linkage, the buoyant float moving with a water level of the tank. A valve release lever has a first end coupled to move with the tank handle and a second end having a cam surface for urging the locking links from a locked to an unlocked position. In a full tank position, the locking links are locked to maintain the valve member in the closed position and the buoyant float may move down without opening the valve. In a flush initiated position, the cam surface of the release lever has unlocked the locking links and, in turn, the valve member moves to the open position. 
         [0010]    Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only an exemplary embodiment of the present disclosure is shown and described, simply by way of illustration of the best mode contemplated for carrying out the present disclosure. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS  
         [0011]    Reference is made to the attached drawings, wherein elements having the same reference character designations represent like elements throughout. 
           [0012]      FIG. 1  is a cut-away of a typical toilet flush tank constructed in accordance with the prior art; 
           [0013]      FIG. 2  is a side elevation view of an exemplary embodiment of a fill valve constructed in accordance with the present disclosure, wherein the fill valve is shown in a “full tank” position; 
           [0014]      FIG. 3  is a side elevation view of the fill valve of  FIG. 1 , wherein the fill valve is shown in a “flush initiated” position; 
           [0015]      FIG. 4  is a side elevation view of the fill valve of  FIG. 1 , wherein the fill valve is shown in a “drained tank” position; 
           [0016]      FIG. 5  is a side elevation view of the fill valve of  FIG. 1 , wherein the fill valve is shown during leakage from the toilet tank between flushes; 
           [0017]      FIG. 6  shows an exploded, perspective view of the fill valve of  FIG. 1 ; 
           [0018]      FIG. 7  is a top end perspective view of another exemplary embodiment of a fill valve constructed in accordance with the present disclosure, wherein a leak prevention mechanism of the fill valve is shown enabled; and 
           [0019]      FIG. 8  is a top end perspective view of the fill valve of  FIG. 10 , wherein the leak prevention mechanism of the fill valve is shown disabled. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0020]      FIG. 1  shows a typical toilet flush tank constructed in accordance with the prior art. The toilet includes exemplary embodiments of a handle, a flush valve, and a fill valve, all constructed in accordance the prior art. The flush valve includes an overflow pipe and a flapper. The handle is connected to a flush arm, which in turn is connected to the flapper with a chain. In  FIG. 1 , the flapper is shown in a closed position covering a drain of the tank. When the handle is turned to flush the toilet, the flush arm and the chain lift the flapper to an opened position. The opened flapper allows “old” water in the tank to drain into the toilet bowl. When the tank is drained or nearly drained the flapper falls back to a closed position to block the drain and allow the tank to be refilled. 
         [0021]    Still referring to  FIG. 1 , the fill valve includes a valve member connected to a buoyant float by a float linkage. When the tank is drained the float drops with the tank water level and pulls open the valve member. The open valve member allows “new” water to flow into the tank from a water inlet. The water is directed from the fill valve through a refill tube to the overflow pipe of the flush valve. As the tank water level rises, the float also rises until the float closes the valve member of the fill valve and stops the water in-flow. The toilet is then ready for another flush cycle. The fill valve shown in  FIG. 1  does not include means for preventing the valve member from being opened should water leak from the tank between flushes and cause the float to lower. 
         [0022]    The present disclosure overcomes many of the prior art problems associated with fill valves. The advantages, and other features of the technology disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth representative embodiments of the present invention and wherein like reference numerals identify similar structural elements. All relative descriptions herein such as top, bottom, left, right, up, and down are with reference to the Figures, and not meant in a limiting sense. Additionally, items not shown in the following figures are provided without reference numerals. In brief overview, the present disclosure provides a fill valve that includes a leak prevention mechanism, which prevents operation of the fill valve should water leak from the tank between flushes. 
         [0023]    Referring to  FIG. 2 , a side elevation view of an exemplary embodiment of a fill valve assembly  100  constructed in accordance with the present disclosure is shown. The fill valve assembly  100  is shown positioned as if the toilet tank were full, e.g., a “full tank” position. The fill valve assembly  100  has a leak prevention mechanism  102  including a valve release lever  104  and locking links  106 ,  108 . 
         [0024]    The top link  106  is pivotally connected to a valve member  130  of the fill valve assembly  100  while the lower link  108  is pivotally connected a valve reset lever  110 . The locking links  106 ,  108  are identical and pivotally connected together. Each link  106 ,  108  has a lower protrusion  106   a ,  108   a  and an upper shoulder  106   b ,  108   b , respectively, best seen in  FIG. 6 . The links  106 ,  108  are arranged so that in a locked position, the lower protrusion  106   a  engages the upper shoulder  108   b  while the lower protrusion  108   a  is urged upward by the valve reset lever  110 . 
         [0025]    The valve reset lever  110  also is pivotally connected to a float linkage  112 . Preferably, the links  106 ,  108 , the lever  110  and the linkage  112  are coupled by pins  114 . The float linkage  112  is secured to a buoyant float  116  that can move up or down on an elongated body  118  of the fill valve assembly  100 . 
         [0026]    The valve release lever  104  is elongated and includes an attachment end  120  and an opposite free end  122 . The free end  122  of the lever  104  is roughly parallel the float linkage  112  in the full tank position. The attachment end  120  has a pivot pin  124  that extends through the cap  126  of the fill valve assembly  100  and pivotally connects the lever  104  to the cap  126 . The pivot pin  124  includes a cam  128  for unlocking the links  106 ,  108  during flushing. The pivot pin  124  may also serve as a banking surface for the links  106 ,  108  when in the locked position. The links  106 ,  108  are coupled to a valve member  130 , which allows water into the tank when open. 
         [0027]    Referring to  FIG. 3 , a side elevation view of the fill valve assembly  100  of  FIG. 1  is shown with the fill valve assembly  100  just after the handle has been used to initiate flushing the toilet bowl, e.g., a “flush initiated” position. The handle temporarily raises the flapper of the flush valve to drain to the toilet tank. As the water drains from the toilet tank, the float  116  moves down along arrow “a”. The float  116  pulls down the float linkage  112  and, thereby, the valve reset lever  110 , but does not move or release the valve member  130  during the downward motion. 
         [0028]    When the handle is turned to flush the toilet, the free end  122  of the lever  104  also moves along arrow “b” as shown in  FIG. 3 . For example, the free end  122  of the lever  104  is connected with a chain to the flush arm so that, the free end  122  is raised along with the flapper of the flush valve. 
         [0029]    As the handle raises the free end  122  of the lever  1 , the pivot pin  124  rotates so that the cam  128  strikes the locking links  106 ,  108 . When the cam  128  strikes the locking links  106 ,  108 , the links  106 ,  108  are pivoted outward and “unlocked” so that the valve member  130  opens. Thus, the valve member  130  is opened only when the toilet handle is turned to flush the toilet. So in the flush initiated position, the toilet tank is draining and, in turn, the float  116  is dropping but rather than the drop of the float  116  opening the valve member  130 , upward movement of the lever  104  has opened the valve member to refill the toilet tank. 
         [0030]    Referring now to  FIG. 4 , a side elevation view of the fill valve of  FIG. 1  with the fill valve assembly  100  in a substantially empty or “drained tank” position is shown. After release of the handle, the lever  104  returns to being vertical but the valve member  130  remains open to put water into the tank. In other words, the links  106 ,  108  remain unlocked even though the lever  104  and cam  128  are no longer urging the links  106 ,  108  unlocked. Once the flapper closes, the tank begins to fill and, in turn, the float  116  rises along arrow “c”. 
         [0031]    As the float  116  moves up, the float  116  pushes the float linkage  112  and the valve reset lever  110  upward, such that the valve reset lever  110  pivots up. The valve reset lever  110  moving up applies a force to the locking links  106 ,  108  by virtue of upwardly engaging the lower protrusion  108   a . As a result, the locking links  106 ,  108  pivot and align end-to-end into the locked position as shown in  FIG. 2 . When the locking links  106 ,  108  are aligned end-to-end in the locked position, the valve member  130  closes (i.e., the valve member  130  pivots upward) and becomes locked. When the valve member  130  closes, water stops entering the tank and the float is substantially returned to the position of  FIG. 2 . Thereafter, the valve member  130  will not pivot downward and open until the locking links  106 ,  108  are pivoted and unlocked by raising the lever  1 . 
         [0032]    Referring now to  FIG. 5 , a side elevation view of the fill valve of  FIG. 1  is shown to illustrate the fill valve assembly  100  during leakage from the toilet tank between flushes. The valve reset lever  110  and the locking links  106 ,  108  are adapted so that pivotal downward movement of the valve reset lever  110  does not cause pivotal movement of the locking links  106 ,  108 . Thus, if when water leaks from the toilet tank and the float  116  moves downward along arrow “d”, the valve reset lever  110  moved pivotally downward but the valve member  130  does not open. As a result, water is conserved. 
         [0033]    The fill valve assembly  100  also includes a pressure relief valve assembly  132  constructed in accordance with U.S. Pat. No. 4,745,945 issued on May 24, 1988, which is incorporated herein by reference in its entirety. The pressure relief valve  132  is adapted to activate at a predetermined pressure to discharge water from a system of piping to relieve pressure due to thermal expansion of water in the piping system. As shown, the relief valve  132  is connected to the body  118  of the fill valve assembly  100 . 
         [0034]    Referring to  FIG. 6 , an exploded perspective view of the fill valve of  FIG. 1  is shown.  FIG. 6  well illustrates several components, features and the interconnections thereof. The following description is directed to some these additional details. Regarding the valve release lever  104 , the free end  122  defines a hole  134  for attaching a connection to the toilet handle. The cap  126  defines opposing apertures  136  for receiving the pivot pin  124 . The valve member  130  also includes pivot pins  138  and a shoulder  140  to couple intermediate the links  106 ,  108 . The valve member  130  seats onto a valve head  142 . The valve member  130  closes a small hole on top of the valve head  142  such that a diaphragm cannot deflate and blocks a water outlet at the top of the elongated body  118 . The links  106 ,  108  do not need to fully align or lock for the valve member  130  to close the small hole. 
         [0035]    The valve head  142  seats into a collar  144  of the elongated body  118 . The collar  144  also provides an anchor point for the valve reset lever  110  and the thermally activated pressure relief valve  132 . The components  146   a - f  of the relief valve  132  are shown and described in more detail in U.S. Pat. No. 4,745,945. A float stop  148  couples to the float linkage  112  to limit of the float  116  in the downward direction. Thus, the tank may simply empty if leaking and await refill until actuation of the handle to open the fill valve assembly  100 . 
         [0036]    In  FIGS. 7 and 8 , another exemplary embodiment of a fill valve assembly  200  constructed in accordance with the present disclosure is shown. The fill valve of  FIGS. 7 and 8  is similar to the fill valve assembly of  FIGS. 1-6 , but further includes a pin  250  for disabling the leak prevention mechanism  202 . Accordingly, like reference numerals preceded by the numeral “2” instead of the numeral “1”, are used to indicate like elements and the following description is directed to the differences only. In brief overview, when the leak prevention mechanism  202  is disabled, the valve member  130  becomes free to operate in a traditional manner, e.g., dropping and rising with the float  116 . 
         [0037]    The pin  250  is fitted on the valve release lever  204  and aligns with a hole  252  in the cap  226  when the lever  204  is raised. By pressing the pin  250  into the hole  252 , as shown in  FIG. 8 , the pin  250  holds the lever  204  up and, in turn, keeps the camming surface  228  urging the links  206 ,  208  in an unlocked position. As a result, the leak prevention mechanism may be selectively disabled. In an alternative embodiment, the pin  250  may simply act as a set screw or catch to maintain the lever  204  in the up position. 
         [0038]    In an alternative embodiment, in a flush initiated position, the cam surface of the release lever has unlocked the locking links so that as the buoyant float drops, the float linkage is pulled to pull the valve reset lever to pull the locking links and, in turn, the valve member moves to the open position. In another alternative embodiment, the lever is simply directly coupled to the pivot pin  114  between the links  106 ,  108  or such area to pull the links  106 ,  108  out of the locked position to open the valve. In an even simpler embodiment, the handle is simply directly linked to the links  106 ,  108  to urge the links  106 ,  108  into the unlocked position. As would be appreciated by those of ordinary skill in the art based upon review of the present disclosure, the linkages and actuation mechanism of the subject technology may be greatly varied and still be well within the scope of the subject invention. 
         [0039]    Thus, the present disclosure provides a new and improved toilet fill valve assembly including a mechanism for preventing leakage. It should be understood, however, that the exemplary embodiments described in this specification have been presented by way of illustration rather than limitation, and various modifications, combinations and substitutions may be effected by those skilled in the art without departure either in spirit or scope from this disclosure in its broader aspects as defined by the appended claims.

Summary:
A toilet fill valve having a mechanism for preventing leakage from a tank of the toilet between flush cycles. The mechanism includes links that are normally locked to prevent the fill valve from opening. The links are operatively connected to a handle of the toilet such that the links are unlocked and allow the fill valve to open only when the handle of the toilet is purposely operated to initiate a flush cycle. Otherwise, the links do not allow the fill valve to open even if water leaks from the tank and causes a float of the fill valve to be lowered.