Patent Abstract:
A filter guard for a pop-up plunger for the drain of a sink or the like which comprises a thin sheet of springy metal having an array of openings therethrough. The sheet is rolled into a cylindrical shape and fitted over the radially extending vanes of a conventional pop-up plunger. The springiness of the sheet causes it to grip the plunger vanes and keep it in place. The openings in the filter guard allow liquid waste to exit the sink but block the passage of discrete articles, such as rings or contact lenses, which may inadvertently fall into the sink.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The present application claims the benefit of Provisional Application Ser. No. 60/479,922, filed Jun. 19, 2003, and entitled “FILTER GUARD FOR SINK DRAIN POP-UP PLUNGER”. The contents of that application are hereby incorporated by reference herein. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention relates to pop-up plungers for waste drain pipes and, more particularly, to a filter guard for such a plunger to prevent large objects from entering the drain pipe while allowing water and waste material to enter the drain pipe.  
           [0003]    Pop-up plungers, in general, are well known for use in selectively closing a waste drain pipe, e.g., in a bathroom lavatory, tub or sink. A conventional pop-up plunger includes a generally circular head portion having a diameter slightly larger than that of the drain pipe and includes a sealing element, e.g., an O-ring, mounted on its undersurface to engage the annular seat at the upper end of the drain pipe. Depending downwardly from the head portion, the plunger is usually formed with a stem having a plurality of equiangularly spaced vanes which project radially outwardly from a central portion of the stem into close proximity with the interior wall of the drain pipe in order to guide the plunger as it moves up and down within the drain pipe. Typically, there are four such vanes which provide relatively large drain passages between adjacent vanes. As a result, when the plunger is in the up, or open, position, in addition to passing water and other waste material, it also passes small objects, such as contact lenses or small pieces of jewelry, which are accidentally dropped into the lavatory, much to the distress of the owner of the object. Once such objects, especially contact lenses, have passed into the waste drain pipe, recovery is extremely doubtful and can be difficult and expensive. While the loss of such objects can be avoided by simply placing the plunger in the down, or closed, position to seal off the drain, such action is rarely contemplated prior to the loss of such an object down the drain.  
           [0004]    U.S. Pat. No. 4,380,834 to Wentz contemplates preventing the loss of discrete objects down the drain by providing a pop-up plunger with an apertured cylindrical sleeve member surrounding the vanes immediately below the head portion of the plunger. The sleeve member is captured between the head portion and shoulders formed on the distal edges of the vanes. While effective, the Wentz device requires a specially designed plunger and is not retrofittable onto existing pop-up plungers.  
           [0005]    It would therefore be desirable to have a filter guard which can be installed on a conventional sink drain pop-up plunger.  
         SUMMARY OF THE INVENTION  
         [0006]    According to the present invention, there is provided a filter guard for a conventional vaned pop-up plunger which comprises an apertured sheet formed into a cylindrical shape, with overlapped ends, of diameter less than the outer diameter of the vaned stem of the plunger. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a front elevational view, partially in section, of a lavatory waste drain system including an embodiment of the present invention;  
         [0008]    [0008]FIG. 2 is an enlarged perspective view of the plunger shown in FIG. 1 with the filter guard according to this invention installed thereon, and wherein the filter guard is only partially shown; and  
         [0009]    [0009]FIG. 3 is a perspective view of an embodiment of a filter guard constructed according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0010]    Referring to the drawings, FIG. 1 shows a portion of a waste drain system, indicated generally by the reference numeral  10 , of the type commonly installed in a typical bathroom lavatory, tub or sink (not shown), and which includes an embodiment of the present invention. The waste drain system  10  includes a generally cylindrical waste drain pipe  12 . One end of the waste drain pipe  12  is conventionally connected as a drain through a suitable trap and additional piping (both not shown) to a waste disposal system, e.g., a septic or sewer system. The other end of the waste drain pipe  12  is adapted for installation within a suitable opening in a lavatory (not shown) and includes a generally enlarged diameter flange which establishes an annular seat  14 . The waste drain pipe  12  further includes a suitable closure actuator, e.g., a lever-type actuator  16  pivoted within suitable bushings  17  within the waste drain pipe  12 , for selectively opening and closing the waste drain pipe  12  in a manner hereinafter to be described.  
         [0011]    In order to provide for controlling the lavatory end of the waste drain pipe  12 , e.g., to close the drain in order to retain water in the lavatory for washing, a pop-up plunger  18  is installed therein as shown. The plunger  18  includes a generally circular head portion  20  having a diameter slightly larger than that of the waste drain pipe  12 . The head portion  20  includes a sealing element, e.g., an O-ring  22 , mounted on its undersurface to engage the annular seat  14  of the drain pipe  12  and operate as a valve element, providing a watertight seal. In FIG. 1, the plunger  18  is in the “up” or open position. By pivoting the actuator  16  upwardly, or counterclockwise, in the bushing  17 , the plunger  18  moves axially downwardly into the waste drain pipe  12  until the sealing element  22  engages the waste drain pipe annular seat  14  to provide a positive drain pipe seal. To open the drain pipe, downward, or clockwise, pivotal movement of the actuator  16  raises the plunger  18  to the position shown in FIG. 1, thereby disengaging the sealing element  22  from the waste drain pipe annular seat  14 .  
         [0012]    As shown in FIGS. 1 and 2, the plunger  18  has a support portion, or stem,  24  which extends, as shown, from the underside of the head portion  20  and into the waste drain pipe  12 . The lower end of the stem  24  includes a suitable connecting element having, for example, an eye  26  for connecting the plunger  18  with the actuator  16 , as shown. As is apparent from FIG. 1, pivotal movement of the actuator  16  results in axial movement of the plunger  18  within the waste drain pipe  12 .  
         [0013]    The plunger stem  24  also includes guide elements, e.g., four vanes, or fins,  28 , which may be tapered and project radially outwardly from a central portion of the stem  24  into close proximity with the interior wall of the waste drain pipe  12  for the purpose of guiding the plunger  18  as it is displaced axially with respect to the waste drain pipe  12 . The four vanes  28  are separated radially from one another to provide four separate drain passages within the waste drain pipe  12  past the plunger  18 . The four vanes  28  are typically equiangularly spaced from each other. Each of the drain passages affords fluid communication from the annular seat  14  past the plunger  18  and the waste drain pipe  12  to the above-described waste disposal system. To the extent described above, the plunger construction is substantially in accordance with a conventional pop-up plunger.  
         [0014]    In accordance with the present invention, a filter guard  32  is provided to prevent passage of discrete objects through the drain passages between the vanes  28  and into the waste disposal system. As shown in FIG. 3, the inventive filter guard  32  is formed from a sheet of material, preferably stainless steel, which is provided with a plurality of openings  34 . Preferably, the openings  34  are circular and are arrayed in a regular pattern, although other shapes of openings can be utilized with other spacing. The openings  34  in the filter guard  32  are large enough so that when the plunger  18  is in the “up” position, a continuous flow of waste liquid may flow therethrough to the drain passages between the vanes  28 . However, the openings  34  are small enough to effectively prevent the entry of any discrete objects, e.g., a contact lens or a small piece of jewelry, into a drain passage. It will be appreciated that the pattern, number, size and/or the shape of the openings  34  may be varied to accommodate the flow desired and the size of the object which is to be excluded. Illustratively, each of the openings  34  is circular with a diameter of approximately 0.10 inches.  
         [0015]    The filter guard  32  is formed from metal sheet stock which is cut into a flat substantially rectangular piece, illustratively 4.0 inches by 1.125 inches, and formed with the openings  34 . The rectangular piece is then formed, as by rolling for example, into a cylindrical shape with its ends  36 , 38  overlapping, as shown in FIG. 3. The unstressed diameter of the rolled cylindrical filter guard  32  is less than the distance between the distal edges  30  of diametrically opposed vanes  28  of the plunger  18 . (In the case where there is an odd number of vanes  28 , the unstressed diameter of the filter guard  32  would be less than the diameter of an imaginary cylinder surrounding and contacting the vanes  28 .) Accordingly, when the filter guard  32  is installed on the plunger  18 , its diameter is expanded so that it slips over the distal edges  30  of the vanes  28 . The material of the filter guard  32  has “memory”, i.e., is springy, so that it tries to contract. In this way, it grips the distal edges  30  of the vanes  28 , and friction between the filter guard  32  and the vanes  28  maintains the filter guard  32  in place.  
         [0016]    The thickness of the filter guard  32  is important for the proper functioning of the invention. If the filter guard  32  is too thick, the plunger  18  with the filter guard  32  attached fits too tightly within the waste drain pipe  12  and the plunger  18  does not move freely to properly open and close the waste drain pipe  12 . Normally, the plunger  18  moves “sloppily” within the drain pipe  12 . It has been found that a filter guard  32  made of stainless steel of thickness 0.005 inches performs satisfactorily on a conventional pop-up plunger installed in a conventional drain pipe.  
         [0017]    The filter guard  32  cooperates with the head portion  20 , the seat  14 , and the drain pipe  12  adjacent the seat  14  to provide an effective barrier against the passage of discrete objects which have a size greater than the size of the openings  34  in the filter guard  32 . After normal use of the drain, it is a simple procedure to wipe around the filter guard  32  and thereby remove any objects or any debris such as hair, dirt particles and the like which are prevented from being discharged with the waste liquid through the drain. In the event that a more thorough cleaning of the filter guard  32  is required, e.g., when hair or other debris entwines itself in the openings  34  and resists normal removal, it is a simple matter to remove the plunger  18  from the drain pipe  12  and slide the filter guard  32  over the eye  26  end of the plunger  18 . After the filter guard  32  is cleaned, it is slid back onto the plunger  18  and the plunger  18  is then reinstalled in the drain pipe  12 .  
         [0018]    As described, the present invention provides a simple retrofittable solution to the problem of preventing discrete objects from inadvertently passing down the drain pipe of a bathtub or sink. The disclosed filter guard can be sold either as a separate item which a customer can install on an existing conventional pop-up plunger, or as part of a pop-up plunger set provided by a manufacturer. While a preferred embodiment of the present invention has been disclosed, it will be apparent to one of skill in the art that various modifications and adaptations to the disclosed embodiment are possible without departing from the spirit and scope of this invention. It is therefore intended that this invention be limited only by the scope of the appended claims.

Technology Classification (CPC): 4