Patent Publication Number: US-6339882-B1

Title: Flush valve

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to toilet valves, and more specifically to flush valves adapted for use in the tank of the toilet. 
     2. Description of the Prior Art 
     A typical toilet construction includes a toilet bowl, and a toilet tank which is initially filled through a fill valve. A flush valve is mounted in the bottom of the tank and is operable to release the water in the toilet tank to flush the toilet bowl. 
     In the past, flush valves have been constructed in a one-piece configuration with a valve seat having a central channel extending along a first axis and a valve elbow having an overflow tube extending along a second axis. A lateral passage provided fluid communication between the overflow tube of the elbow and the central channel of the seat. A flapper valve has been pivotal on the elbow and operable with respect to an opening on the seat to open and close the valve. 
     Initially, the opening in the valve seat was defined in a plane perpendicular to the axis of the valve seat and parallel to the bottom of the tank. This configuration provided the best loading of the flapper valve in the closed state. The one-piece construction was formed as a brass casting. 
     As the cost of castings increased, the industry began to look to injection molding for its economies of scale. Improving on the one-piece construction, injection molding could only be achieved using a core pin to define the lateral passage between the valve seat and the valve elbow. Lateral removal of this core pin required that the opening into the valve seat be canted from the prior perpendicular relationship with the axis of the seat. By canting the opening, the core pin, which was necessary to define the lateral channel, could be both inserted and removed through the opening. This process greatly reduced the unit cost of the product, but this was achieved only with the disadvantages associated with a candid valve seat and a generally reduced magnitude of flow. This magnitude of flow was dependent upon the size of the lateral channel which was necessarily limited by the size of the cord pin which could be inserted and removed through the candid opening. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a flush valve is provided with the economies of scale resulting from injection molding, along with a perpendicular valve opening providing uniform valve loading, and an enlarged lateral channel facilitating a higher flush rate. 
     The flush valve is constructed in two portions, a valve seat having a first sleeve in a valve opening having a second sleeve registerable with the first sleeve to create the lateral (passage). During the injection molding of the valve seat, a cord pin defining the first sleeve is removable, not through the valve opening, but laterally of the valve seat. Similarly, a cord pin defining the second sleeve in the injection molding of the valve elbow can also be removed laterally. In a final step achieving a one-piece construction, the second sleeve is inserted into the first sleeve in a friction fit relationship to define the lateral passage. Since the size of this passage is not dependent upon the size of the valve opening, it can be made larger thereby increasing the flush volume. Also, since it is not necessary to insert or remove a cord pin through opening, the opening can be formed in its preferred perpendicular relationship with the axis of the seat to provide for substantial uniform valve loading. 
     These and other features and advantages of the invention will be better understood with a discussion of preferred embodiments and reference to the associated drawings. 
    
    
     A DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation partially in construction showing the interior of a toilet tank; 
     FIG. 2 is an exploded perspective view of a valve seat, valve opening flush tube and flapper associate with the flush valve of the present invention; 
     FIG. 3 is a top plan view of the valve seat illustrated in FIG. 2; 
     FIG. 4 is a radial cross section view with technical long lines  4 — 4  of FIG. 3; 
     FIG. 5 is a side elevation view with technical long lines  5 — 5  of FIG. 3; 
     FIG. 6 is a top plan view of the valve elbow illustrated of FIG. 2; 
     FIG. 7 is a radial cross section view with technical long lines  7 — 7  of FIG. 6; 
     FIG. 8 is a side elevation view with long lines  8 — 8  of FIG. 6; and 
     FIG. 9 is a side elevation view of a further embodiment of the invention. 
     FIG. 10 is a radial cross section view showing the core pin used to define the first sleeve. 
     FIG. 11 is a radial cross section view showing the core pin define the second sleeve. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION 
     A flush valve is illustrated in the side elevation view of FIG.  1  and designated generally by the reference numeral  10 . The flush  10  in this embodiment is mounted in a toilet  12  which includes a toilet tank  14  and a toilet bowl  16 . In a typical manner, the flush valve  10  is mounted in a hole  15  and controls fluid flow between the tank  14  and bowl  16 . As shown in FIG. 1, the flush valve  10  includes a valve seat  18 , a flapper  21 , a valve elbow  23 , and an overflow tube  25 . 
     In addition to the flush valve  10 , the toilet  14  includes a fill valve  30  which is mounted within the tank  14  and includes a float  32  and bowl fill tube  32 . In operation, the fill valve  30  receives water from outside the toilet  12  and fills the tank  14  to a predetermined level controlled by the float  32 . As water is received within the tank  14  through the fill valve  30 , a portion of the water is introduced through the bowl fill tube  32  into the overflow tube  25  to partially fill the bowl  16 . The toilet  12  can be flushed by operation of an exterior button or handle which functions to lift the flapper  21  from the valve seat  18  and empty the water within the tank  14  into the bowl  16 . After completion of the flush, the flapper  21  seals the seat  18  to permit filling of the tank  14  by the valve  30 . 
     The flush valve  10  of the present invention is illustrated in the exploded view of FIG.  2 . In this view it can be seen that the valve seat  18  can be formed with an annular flange  38  which divides the seat  18  between an upper section  41  and a lower section  43 . 
     The lower section  43  which extends along a valve seat axis  45 , is preferably formed with the configuration of a cylinder  50  having exterior threads  52 . When operably mounted, the cylinder  47  is inserted into the hole  15  extending between the tank  14  and the bowl  16 , where the exterior threads  52  are engaged by a nut  54  to form a seal between the bottom of the tank  14  and the annular flange  38 . 
     The top section  41  includes a sidewall  61  which has a frusto-conical configuration. This sidewall  61  defines a central channel  63  which extends from the cylinder  47  in the lower section  43 , upwardly to portions  64  which define an enlarged hole or opening  63  at the top of the valve seat  18 . These portions  64  of the sidewall  61  define the opening  63  in an orientation that is of particular significance to the present invention. Since these portions  65  form a seat for the flapper  21 , uniform loading of the flapper  21  is achieved when the opening  63  is defined in a horizontal plane which is generally perpendicular to the axis  45 . 
     In this embodiment, the cylinder  47 , flange  38 , sidewall  61 , opening  63  and flapper  21  all have a circular configuration in radial cross-section. This configuration is best illustrated in the plan view of FIG.  3 . 
     The valve seat  18  also includes a sleeve  70  which extends laterally of the sidewall  61  in communication with the central channel  63 . This sleeve  70  preferably has a non-circular configuration, which is rectangular in the preferred embodiment. This rectangular configuration is best illustrated in the cross section view of FIG.  4  and the side view of FIG.  5 . 
     FIG. 2 also illustrates an elbow  81  which forms a portion of the flush valve  10 . This elbow  81  includes a cylinder  83  which is sized and configured to receive the overflow tube  25 . The cylinder  83  can be provided with exterior support arms  85  and  87  which extend laterally in opposite directions to pivotally support the flapper  21 . The cylinder  83  defines an overflow channel  90  which extends generally along an axis  92  of the elbow  81 . A second sleeve  94  extends laterally of the cylinder  83  in fluid communication with the overflow channel  90 . The overflow channel  90  is best illustrated in the plan view of FIG.  6 . The preferred rectangular cross-sectional configuration of the second sleeve  94  is best illustrated in the cross-sectional view of FIG.  7  and the side view of FIG.  8 . 
     One of the final steps in the construction of the flush valve  10  is the telescopic engagement of the first sleeve  70  of the valve seat  18  and the second sleeve  94  of the valve elbow  81 . With the sleeves  70  and  94  provided with similar cross-sectional configurations, the second sleeve  94  can be inserted into the first sleeve  70  to define a lateral passage  100  which extends in fluid communication with the overflow channel  90  of the elbow  81  and the central channel  63  of the valve seat  18 . With an appropriate control of tolerances, the second sleeve  94  can be forced into the first sleeve  70  to provide a fictional fit and a generally sealed relationship. 
     A method of manufacturing a flush valve  110  of the prior art is illustrated in FIG.  9 . This valve  110  was injection molded using a core pin  112  to define a passage  114  in a valve seat  116 . In order to define the passage  114  horizontal and generally perpendicular to the axis of the seat  116  and elbow  118 , it was necessary to cant or incline the opening into the seat  116 . Unfortunately this provided non-uniform loading of the flapper seat and also limited the cross-sectional area of the passage  114 . 
     A method of the present invention is illustrated in FIG. 10 where a core pin  121  is used to define the first sleeve  70 . Since the flush valve  10  is not required to be injection molded as a single piece, the core pin  121 , which is used to define the sleeve  70 , need not be inserted through the opening  64  defined by the sidewall portions  65 . Rather, the pin  121  can be inserted and removed laterally as shown by the arrow  123 . As a result, the passage  100  is not limited by the size of the opening  64 . Nor is the orientation of the opening  64  required to be canted as was the case with the injection molded devices of the prior art. 
     This same advantage can be achieved in injection molding the valve elbow  81  as illustrated in FIG.  11 . In this case, a core pin  130  can be used to mold the second sleeve  94 . This pin  130  can also be inserted and removed laterally as shown by the arrow  132 . Once again, the lateral passage  100  can be formed without any concern for the size of the opening  63  or the canting of its plane of orientation. 
     In the final assembly step, the second sleeve  94  can be inserted into the first sleeve  70  to form the flush valve  10 . While maintaining the advantages of injection molding, the resulting valve  10  has uniform sealing pressure with the plane of the opening  64  generally horizontal and perpendicular to the axis  45 . The lateral passage  100  can be maximized without any limitations based on the size of the opening  63 . The size of the lateral passage  100  can be maximized without any limitations based on the size of the opening  63 . This facilitates the larger overflow volume which is of significant advantage to the flush valve  10 . 
     It will be apparent that many of the advantages of this construction can be achieved in other embodiments of the flush valve  10 . For example, as illustrated in FIG. 9, a one-piece injection molded construction can be achieved with the opening  63  defined generally perpendicular to the axis  45 . In constructing this embodiment, a core pin  140  can be inserted and removed through the opening  63  as taught by the prior art. However, in this case, the core pin  140  defines the lateral channel  100  at an angle other than 90 degrees to the axis  45 . Accordingly, the lateral channel is canted so that the opening  64  can be maintained in the horizontal orientation to achieve uniform loading of the flush valve  10 . 
     These and other modifications to the disclosed embodiments will be apparent to those skilled in the art. As a result, one is cautioned not to determine the extent of this concept only with reference to the disclosed embodiments, but rather encouraged to determine the scope of the invention only with reference to the following claims.