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FIELD OF THE INVENTION  
         [0001]    The present invention relates to water-saving devices, and particularly to a water-stop plug for adjusting water-draining of a stool, wherein in the stool of the present invention, the water supply of the water-stop plug is adjustable according to the requirement of the user so as to save supplied water.  
         BACKGROUND OF THE INVENTION  
         [0002]    Stool has become a necessary device for the currently life, but generally, the water supplied to the stool is unadjustable and a large amount of water is supplied for each time the stool is used so that water is wasted. Tools are necessary for adjusting water supplied to the stool, however, this is inconvenient, and thus the user can not determine the water to flush a stool each time the stool is used.  
           [0003]    A prior art water-stop plug is illustrated in FIG. 1. In that prior art, a linkage  12  is controlled by the handle  11  so that a chain  13  is driven to pull the cover  15  of the plug  1  to drain water. Thus, the water in the water box drains out from a draining tube  17 . A pontoon  14  is engaged with the chain  13 . By adjusting the level of the pontoon  14 , the speed of the cover  15  to cover an object is controllable so as to achieve the object of saving water. However, the disadvantage of this prior art is that adjustment of the pontoon  14  is insensitive and thus the object of saving water can not be well controlled.  
         SUMMARY OF THE INVENTION  
         [0004]    Accordingly, the primary object of the present invention is to provide a water-stop plug for adjusting water-draining of a stool comprising a cover, a water-stop washer, a small washer and a plug. The water supply of the water-stop plug of a stool is adjustable according to the requirement of the user so as to save supplied water.  
           [0005]    To achieve above objects, the present invention provides a water-stop plug for adjusting water-draining of a stool, which comprises a cover, a water-stop washer, a small washer and a plug.  
           [0006]    The cover is a round piece with a diameter slightly larger than a diameter of the water box draining tube. A plug is coupled to the water-stop washer; one side of the cover is extended with a pair of symmetrical extending arms; a distal end of each extending arm is formed with a second notch. The water-stop washer is a round soft piece with a round hole at a center portion thereof; and the water-stop washer is mounted between the cover and the plug as a draining-preventing means. The small washer is a round hard piece with a round hole at a center portion thereof; and a plug is a hollow hemisphere. A top thereof is formed with a water inlet, and one lateral side has an air hole. A lower portion of the plug is extended with a flange.  
           [0007]    The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a schematic view of the pontoon adjustment in the prior art.  
         [0009]    [0009]FIG. 2 is an exploded perspective view of the present invention.  
         [0010]    [0010]FIG. 3 is a schematic cross sectional view of the present invention.  
         [0011]    [0011]FIG. 4 shows one operation of the present invention.  
         [0012]    [0012]FIG. 5 shows another operation of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    Referring to the appended drawings, the water-stop plug for adjusting water-draining of a stool of the present invention is illustrated.  
         [0014]    With reference to FIGS. 2 and 3, an exploded perspective view of the present invention and a partial schematic view of the present invention are illustrated. The present invention has a cover  22 , a water-stop washer  23 , a small washer  24  and a plug  25 .  
         [0015]    The cover  22  is a round piece the diameter of which is slightly larger than the tube diameter of the water box draining tube. The center thereof has an annular rib  221 . At least one notch  222  is formed on the edge of the annular rib  221 . The edge of the annular rib  221  having the notch  222  has a reduced step to be formed as a buckle edge  223  for being engaged with the water-stop washer  23  and the small washer  24 . Then a plug  25  is coupled to the water-stop washer  24 . One side of the cover  22  is extended with a pair of symmetrical extending arms  224 ,  225 . A distal end of each extending arm  224  ( 225 ) is formed with a notch  2241  ( 2251 ). Two posts  321  at two sides of the lower section of the water tube  32  can be coupled to the notches  2241 ,  2251 . Thereby, the posts  321  are utilized as fulcrums and the backside of the cover  22  has a hooking hole  226  for hooking a chain  21 . Another end of the chain  21  is hooked to the linkage  33 .  
         [0016]    The water-stop washer  23  is a round soft piece with a round hole  231  at a center portion thereof. The water-stop washer  23  is mounted between the cover  22  and the plug  25  as a draining-preventing means.  
         [0017]    The small washer  24  is a round hard piece with a round hole  241  at a center portion thereof.  
         [0018]    The plug  25  is a hollow hemisphere. A top thereof is formed with a water inlet  251 , one lateral side has an air hole  252 . A lower portion of the plug  25  is extended with a flange  253 .  
         [0019]    In assembly, the water-stop washer  23 , small washer  24  and plug  25  are sequentially assembled to the annular rib  221  of the cover  22 . By the notches  2241  and  2251  on the extending arms  224 ,  225  of the cover  22  to hook the posts  231  at the lateral side of the water tube  32 , the cover  22  can cover the hooking hole  226  of the linkage  33  and the cover  22  (referring to FIG. 3). As a result, when one air hole  252  of the plug  25  is positioned at an upper side, as shown in FIG. 4, and the cover  22  is opened, since the water pressure of the water box will reduce with the reduction of the water level, the water in the water box will flow into the plug  25  from the water inlet  251 . Thus the plug  25  become heavier. Thus, the cover  22  will sink downwards to cover a draining hole  31 , but now the water in the water box does not drain out completely. Thus the water used is reduced. When the plug  25  is rotated so that the air hole  252  is positioned at a lower position (referring to FIG. 5), the water in the water box will drain out. Due to the water pressure effect of the water in the water box, it is difficult for the water to flow into the plug  25 . As a result, the cover  22  covers the plug  25  slowly. Thereby, the water in the water box is drained out completely by the positioning of the air hole  252  of the plug  25 . Therefore, the speed of the covering operation is controlled, and thus the water stored in the water box is adjustable.  
         [0020]    The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Summary:
A water-stop plug for adjusting water-draining of a stool comprises a cover, a water-stop washer, a small washer and a plug. The water supply of the water-stop plug for adjusting water-draining of a stool is adjustable according to the requirement of the user so as to save supplied water. By adjusting an air hole on a plug, the supplied water is adjustable.