Patent Abstract:
A backflow prevention device for use with a conventional washing machine system that is uniquely designed to automatically disrupt the power to the washing machine should the drain line leading from the washing machine become clogged. The backflow prevention device includes an internally mounted micro switch that is operably interconnected with a portable ground fault circuit interrupter plug that is connected to a duplex outlet. The washing machine is connected to the ground fault circuit interrupter plug so that, upon being actuated, the micro switch will cause a low voltage default to be sent to the ground fault circuit interrupter which triggers it in a manner to automatically cause an interruption of power to the washing machine.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to fluid flow control devices. More specifically, the invention concerns an overflow prevention device that can be attached to the drain line of a conventional clothes washing machine system and is so constructed and arraigned to automatically disable the washing machine in the event that the washing machine drain becomes clogged.  
           [0003]    2. Discussion of the Prior Art  
           [0004]    The typical prior art washing machine is usually connected to a household waste system through an upright drain conduit that is, in turn, interconnected with the household sewer system. Since the modern washing machine includes automatic features that enable the washing machine to be used in an unattended fashion, the accidental clogging of the waste line leading to the domestic sewer almost always results in the overflow of rather large quantities of water. Accordingly, several types of overflow control devices have been suggested in the past to avoid this undesirable result. Exemplary of these prior art devices is that disclosed in U.S. Pat. No. 4,418,712 issued to Braley. The Braley invention includes a conductivity pressure sensor that is placed within the drain or standpipe of the washing machine system for sensing the height of liquid therein. The invention further includes a ground fault circuit interrupter and an optional audible alarm both of which can be operably interconnected with the pressure sensor.  
           [0005]    Another type of overflow control device is described in U.S. Pat. No. 5,028,910 issued to Meacham et al. The Meacham patent discloses an overflow device that includes a vertical offset standpipe extending from a conventional standpipe. The offset standpipe has a flow-actuated switch disposed there within that is engaged when the water level rises in the offset standpipe.  
           [0006]    The patent to Mills, U.S. Pat. No. 5,125,247 discloses a device that is somewhat similar to the Meacham device. However, the flow-actuated switch of the Mills device is located in the main standpipe and not in a secondary standpipe.  
           [0007]    The apparatus of the present invention overcomes many of the drawbacks of the prior art overflow control systems and, in one form, includes a backflow preventor having an inflow end and an outflow end. The outflow end is receivable within a drainpipe such as a two-inch plastic standpipe of the character typically used as a washing machine drain. The inflow end of the device, which includes a stepped outer surface to accommodate drain hoses of various sizes, is sealably connected to the washing machine drain hose. A swing type check valve or flapper is mounted internally of the device. The valve is pushed open when water flows from the washing machine to the drain in a normal fashion. However, if the drain backs up and the water flow reverses direction the flapper is pushed closed. This drain backup also causes a strategically located plunger to move upwardly against the urging of a biasing means. Upward movement of the plunger operates an internally mounted micro switch that is operably connected to a portable ground fault circuit interrupter plug. The washing machine is connected to the ground fault circuit interrupter plug, which, in turn, is connected to a conventional duplex wall outlet. With this novel arrangement, when the flapper is closed and backflow pressure from the drain builds up in the outflow end of the valve, the switch is actuated by the upward movement of the plunger. Actuation of the switch causes a low voltage default which triggers the ground fault circuit interrupter, thereby interrupting power to the washing machine.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to provide a backflow prevention device of simple construction that can be used with a conventional washing machine system and one which is uniquely designed to automatically disrupt the power to the washing machine should the drain line leading from the washing machine become clogged.  
           [0009]    Another object of the invention is to provide a backflow prevention device of the aforementioned character that is reliable in operation and easy to connect to washing machine drain hoses of various sizes. More particularly, the inflow end of the backflow prevention device includes a stepped outer surface that will accommodate drain hoses of various sizes.  
           [0010]    Another object of the invention is to provide a backflow prevention device as described in the preceding paragraphs that includes an internally mounted micro switch that is actuated upon the washing machine drain becoming clogged. The micro switch is operably interconnected with a portable ground fault circuit interrupter plug that is connected to a duplex outlet and to which the washing machine is connected. Upon actuation, the switch causes a low voltage default to be sent to the ground fault circuit interrupter that triggers the ground fault circuit interrupter thereby automatically causing an interruption of power to the washing machine.  
           [0011]    Another object of the invention is to provide a backflow prevention device of the character described that includes a generally cylindrical connector member having an inflow end and an outflow end. The outflow end is sealably receivable in the standpipe used as the washing machine drain. The outflow end includes an O-ring type seal for sealing the joint between the sleeve and the outflow end so that the backflow prevention device can be easily removed from the standpipe when it is necessary to clear blockages in the washing machine drain system.  
           [0012]    Another object of the invention is to provide a backflow prevention device that is easy to install and one that can be used with almost any type of conventional commercially available washing machine and like appliance. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a generally perspective view showing the device of the invention interconnected with a conventional washing machine system.  
         [0014]    [0014]FIG. 2 is a greatly enlarged, generally perspective view of one form of the backflow prevention device of the invention.  
         [0015]    [0015]FIG. 3 is an enlarged, cross-sectional view of the backflow prevention device shown in FIG. 2.  
         [0016]    [0016]FIG. 4 is a generally perspective, exploded view of the backflow prevention device shown in FIG. 2. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0017]    Referring to the drawings and particularly to FIGS. 1 and 2, one form of the invention can be seen to comprise in combination a washing machine  10  powered from an electrical outlet  12  via current flowing through an electric circuit and a backflow prevention system generally designated by the numeral  14 . The washing machine  10  is adapted to receive water from a water supply (not shown) at predetermined intervals in a washing cycle and to remove the water through a drain hose  16  at predetermined intervals in the washing cycle. A standpipe  18  is interposed between the washing machine  10  and the household drainage system for conveying water to the household drainage system.  
         [0018]    In the present form of the invention, the backflow prevention device comprises a hollow housing  20  defining a flow passageway  22  having an inlet  24  (FIG. 3) interconnected with the drain hose  16  and an outlet  26  interconnected with standpipe  18 . A valve, such as a flapper valve assembly  28 , is mounted within flow passageway  22  intermediate the inlet and the outlet. Valve assembly  28 , which comprises a valve member  28   a  and a cooperating gasket  28   b , is movable from a first closed position shown by the solid lines in FIG. 3 to a second open position shown by the phantom lines in FIG. 3 in response to water flowing into the inlet. Valve  28  is movable from the second open position to the first closed position in response to water flowing from outlet  26  toward inlet  24  in the direction of arrow  27  of FIG. 3. A valve biasing means, which is connected to the hollow housing, yieldably urges the valve toward said first closed position.  
         [0019]    Forming an important feature of the backflow prevention device of the present invention is switch means, which is carried by housing  20  and is operably associated with the electric circuit for interrupting the flow of current through the electric circuit upon actuation of the switch means. The backflow prevention device also includes operating means carried by housing  20 . The operating means is operably associated with the switch means and functions to operate the switch means in response to water flowing from outlet  26  toward inlet  24 . The construction and operation of these important features of the invention will be described in greater detail the paragraphs which follow.  
         [0020]    Referring particularly to FIG. 3, it is to be noted that hollow-housing  10  includes first and second side chambers  30  and  32  that are in communication with flow passageway  22 . In the present form of the invention, the operating means comprises a plunger  34  that is reciprocally movable within side chamber  30  from a first position to a second position in response to water flowing from outlet  26  toward inlet  24  (see also FIG. 4). An elastomeric O-ring  35  prevents fluid leakage past the plunger. Plunger  34  includes an elongated, outwardly protruding operating stem  34   a , the purpose of which will presently be described. As best seen in FIG. 3, the upper portion of chamber  30  is closed by a cap  38  having a central aperture  38   a  through which stem  34   a  protrudes.  
         [0021]    Connected to cap  38  is a hollow switch housing  40  within which the switch means of the invention is mounted. The switch means here comprises a readily commercially available micro switch  42  that is operably associated with the electric circuit of the apparatus for interrupting the flow of current upon actuation of the micro switch by the operating means of the invention. Micro switch  42  is available from various commercial sources such as Micro Switch Co. of Freeport, Ill. Micro switch  42  includes a downwardly extending operating arm  42   a  that is engageable by stem  34   a  as plunger  34  is moved upwardly within chamber  30  in response to fluid flowing from outlet  26  toward the plunger in the direction of arrow  27  (FIG. 3). As illustrated in FIG. 1, micro switch  42  is operably interconnected by means of the electrical conduit  44  with a portable ground fault circuit interrupter (GFCI) plug  46  that also forms a part of the circuit interrupting means of the invention.  
         [0022]    GFCI plug  46  is readily commercially available from various sources, including TRC of Clearwater, Fla. The details of the construction and operation of plug  46  can be obtained from the TRC Company and are also described in U.S. Pat. No. 4,567,456 issued to Legatti. Reference should be made to this patent for an understanding of the operation of GFCI plug  46 . As shown in FIG. 1, plug  46 , which is plugged into duplex outlet  12 , is constructed and arranged to receive the power plug  10   a  of the washing machine  10  which is, in turn, connected to the washing machine power cord  10   a . With the arrangement shown in FIG. 1, the reset switches  46   a  of the GFI plug are readily accessible. As previously mentioned, micro switch  42  is operably interconnected with plug  46  by electrical conduit  44 . More particularly, the wires of conduit  44  are connected at one end to the upper terminals of the micro switch and are connected at the other end in parallel to the leads running to the reset switches  46   a  of the GFI plug  46 . This electrical interconnection of micro switch  42  with the GFI plug  46  is well understood by those skilled in the art.  
         [0023]    In using the apparatus of the invention, a waste line connector means, which here comprises a generally cylindrically shaped member or connector collar  50  is connected to the upper open end of the standpipe  18 . As best seen in FIG. 3, member  50  has an open top portion and an inwardly tapering sidewall that is sealably receivable within standpipe  18  and a manner shown in FIG. 1. With a connector collar thusly sealably inserted into the upper end of the standpipe  18  and locked in place by the bayonet type locking arrangement  51 , the lower cylindrical portion  20   a  of hollow housing  20  is inserted into the connector collar  50  in the manner shown in FIG. 3. As shown in FIG. 3, hollow-housing  20  includes a flange  20   b  that engages the upper portion  50   a  of collar  50  when the lower portion of the hollow housing is fully seated within the connector collar. An elastomeric O-ring  52  and is disposed between the flange  20   b  and upper portion  50   a  to prevent leakage between the mating components.  
         [0024]    With the hollow housing  20  mated with the standpipe  18  in the manner described in the preceding paragraph, the water supply connector means of the invention is connected to the upper portion of second chamber  32  in the manner best seen in FIG. 3. In the present form of the invention, the water supply connector means comprises a hollow member  54  made up of a plurality of interconnected, generally cylindrically shaped segments of different outside diameters, such as segments  54   a ,  54   b ,  54   c ,  54   d  and  54   e . The novel construction of member  54  permits the convenient interconnection therewith of drain lines of various inside diameters.  
         [0025]    During the normal operation of the washing machine, as the water flows from the washing machine to the drain hose  16 , flapper valve  28  is pushed open against the urging of a flapper valve biasing means shown here as a torsion spring  56 . However, if the drain becomes clogged causing the drain water to back up and to flow in the direction of the arrow  27 , the flapper valve  28  will be pushed closed in the manner shown by the solid lines in FIG. 3. This drain backup and reverse flow of the drain water also causes plunger  34  to move upwardly against the urging of a plunger biasing means shown here as a coil spring  58 . Upward movement of the plunger causes the plunger stem  34   a  to engage the downwardly extending switch operating arm  42   a  in a manner to actuate micro switch  42 , which as previously mentioned, is operably associated with the portable ground fault circuit interrupter plug  46 . As also previously mentioned, washing machine  10  is electrically connected to the ground fault circuit interrupter plug, which, in turn, is connected to the conventional duplex wall outlet  12 . Actuation of micro switch  42  causes a low voltage default to be sent to the ground fault circuit interrupter, which triggers the ground fault circuit interrupter causing an automatic interruption of the power flowing to the washing machine.  
         [0026]    Following an interruption in power, the backflow prevention body  20  can be easily removed from the connector collar  50  to enable the clog in the drain system to be cleared. Once the clog is cleared, body  20  can be once again sealably interconnected with connector collar  50  and the ground fault circuit interrupter plug  46  can be reset using reset switches  46   a . This done, normal operation of the washing machine can once again commence.  
         [0027]    Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.

Technology Classification (CPC): 3