Patent Publication Number: US-7216373-B2

Title: Toilet tank valve seat structure

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a toilet tank valve seat structure and particularly to a valve seat that has an overflow tube with an adjustable length and a plug easy to couple. 
   2. Description of the Prior Art 
   Referring to  FIG. 1 , a conventional valve seat  1  of a toilet tank includes a body  10  and an overflow tube  11  located on one side of the body. The overflow tube  11  has an overflow outlet  111  at the top end to discharge excessive water through a valve opening  101  to prevent the water in the tank from spilling outside the tank. The overflow tube  11  has a strut  102  on a lower side to couple with an anchor notch  121  of a stopping cap  12 . The stopping cap  12  has a seal pad  122  to cover the upper side of the valve opening  101  and is driven by a chain  13  to move about the strut  102  which serves as a fulcrum to control the water to flush from the tank into the toilet. Such a structure still has problems in practice, notably:
         1. The overflow tube  11  has a fixed length and must be cut to a corresponding height according to the water level. If the length of the overflow tube is not proper, or the water level is altered, the overflow tube  11  cannot function as desired, and the valve seat has to be replaced.   2. After the stopping cap  12  has been used for a period of time, the seal pad  122  could be aged and hardened, and the sealing effect is impaired. Hence the seal pad has to be replaced periodically. Due to the strut  102  and the anchor notch  121  are coupled forcefully, removing or coupling of the two could result in breaking of the strut  102  or hurting user&#39;s hands.       

   SUMMARY OF THE INVENTION 
   In view of the aforesaid disadvantages, the primary object of the present invention is to provide an improved toilet tank valve seat structure to overcome the problems of the overflow tube whose length cannot be adjusted to suit change of water level and the plug which is not easy to replace. The invention provides an overflow tube which has an alterable length to suit different water levels and an elastic anchor notch to make replacing of the plug easier. 
   The valve seat according to the invention mainly includes an overflow tube on one side of a body. The overflow tube has an inner tube and an outer tube. The inner tube has a gear rack on one side to couple with a hook on one end of the outer tube so that the outer tube may be moved up and down to adjust the length of the overflow tube. The body has a valve opening to couple with a plug on the upper side. The plug has an anchor notch with two slots formed on two sides so that the anchor notch has a greater elasticity to facilitate coupling. The structure allows the length of the overflow tube to be adjusted to suit water level and makes coupling and replacing of the plug easier. 
   The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a fragmentary sectional view of a conventional valve seat. 
       FIG. 2  is an exploded view of the invention. 
       FIG. 3  is a sectional view of the invention. 
       FIG. 4  is a schematic view of the invention for adjusting the overflow tube. 
       FIG. 5  is a schematic view of the invention for coupling operation. 
       FIG. 6  is a schematic view of the invention showing plug operation- 1 . 
       FIG. 7  is a schematic view of the invention showing plug operation- 2 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 2 and 3 , the valve seat  2  according to the invention mainly includes a body  20 , an overflow tube  21  and a plug  22 . 
   The body  20  has a valve opening  201  which has one side communicating with a water discharge outlet  202  to form a jutting dock  203 . The jutting dock  203  has two L-shape struts  204  extending from two sides. The body  20  has an external screw thread section  205  on the outer side. 
   The overflow tube  21  includes an inner tube  211  and an outer tube  212 . 
   The inner tube  211  is hollow and has one end mounted onto the jutting dock  203 , a gear rack  2111  located on one side, and a bulged rim  2112  on the top end. The bulged rim  2112  has an annular groove  2113  to couple with a seal ring  2114 . 
   The outer tube  212  is hollow to couple with the inner tube from outside. It has a hook  2121  and a bulged rim  2122  on the inner side of a lower end. The hook  2121  is engageable with the gear rack  2111  of the inner tube  211 . The bulged rim  2122  presses the outer side of the inner tube  211  and is confined below the bulged rim  2112  of the inner tube  211  so that the outer tube  212  may slide up and down without breaking off. The top end of the outer tube  212  is coupled with a water intake head  2123 . 
   The plug  22  includes a cap  221 , a seal pad  222 , a washer  223  and a plug dome  224 . 
   The cap  221  is a circular tray slightly larger than the valve opening  201 . The seal pad  222 , washer  223  and plug dome  224  are coupled on the bottom of the seal cap  221  in this order. It has two arms  2211  on two sides. The distal end of the arms  2211  has an anchor notch  2212  to couple on the strut  204  of the body  20 . There are two slots  2213  on two sides of the anchor notch  2212 . The cap  221  has an aperture  2214  on another side to couple with a chain  2215 . 
   The seal pad  222  is a pliable blade with an outer diameter slightly larger than the valve opening  201 , and has a round opening  2221  in the center to couple with the lower side of the cap  221 . 
   The washer  223  is a hard blade sandwiched between the seal pad  222  and the plug dome  224  to reduce the friction resistant force when the plug dome  224  is turned. The washer  223  has a round opening  2231  in the center. 
   The plug dome  224  is a hollow semi-spherical member located below the cap  221  and is turnable. It has a water inlet  2241  on the bottom and an air vent  2242  on one side. 
   By means of the elements and construction set forth above, the outer tube  212  is coupled on the inner tube  211  from outside with the hook  2121  latching on the gear rack  2111 . The outer tube  212  may be moved up and down for a selected distance to adjust the length of the overflow tube  21  to suit the water level of the tank (referring to  FIG. 4 ). Moreover, The slots  2213  on two sides of the anchor notch  2212  provide the anchor notch  2212  with a desired elasticity so that it may be expanded towards two sides when coupling with the struts  204  without causing damages (referring to  FIG. 5 ). 
   Referring to  FIGS. 6 and 7 , the plug dome  224  of the plug  22  also provides water discharge adjustment function. When the air vent  2242  of the plug dome  224  is located on a upper side (referring to  FIG. 6 ), and the cap  221  opens, the water level drops and water pressure decrease gradually, the water in the tank continuously flows through the water inlet  2241  into the plug dome  224 . The plug dome  224  becomes heavier and result in the plug  22  sinking to close the valve opening  201 . Due to the water in the tank is not yet fully depleted, such a mechanism can save water consumption. On the other hand, when the plug  224  is turned and the air vent  2242  is located on a lower position (referring to  FIG. 7 ), and the water in the tank starts discharging, due to the inverse pressure effect caused by pressure difference, water in the tank is difficult to enter the plug dome  224 , thus the plug  22  closes slowly, and the water in the tank can be fully discharged. Therefore by turning the plug dome  224  to alter the location of the air vent  2242 , the closing speed of the plug  22  may be controlled to adjust the amount of the storing water. 
   In summary, the invention provides an overflow tube that has an adjustable length to suit different water levels and a plug which is easier to couple and replace. It offers a significant improvement over the conventional techniques.