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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
   This invention relates to a bathtub drain closure assembly. More particularly, this invention relates to a bath drain closure device that is opened and closed when the water level in the bathtub reaches a given level. 
   Bathtubs are often left unattended while filling. Accordingly, overflow drains are typically supplied to prevent overflow from the bathtub. However, even with overflow drains it is still possible for the bathtub to overflow if the overflow drain is of insufficient capacity or if a person suddenly enters an overfull bathtub. 
   It is therefore a principal object of this invention to provide a drain closure assembly for a bathtub which opens the bottom drain when the water level in the bathtub reaches a given level. 
   These and other objects will be apparent to those skilled in the art. 
   SUMMARY OF THE INVENTION 
   A bath drain assembly for use with a bathtub having a drain closure device associated with a bathtub drain and a movable actuating member engaging the drain closure device such that the drain closure device is toggled between open and closed positions when actuated. 
   A sensor, mounted in a position to detect the water level within the bathtub, provides a signal that changes the position of the actuating member which moves the drain closure device to an open position to allow water to drain from the tub. 

   
     DESCRIPTION OF THE DRAWINGS AND PHOTOS 
       FIG. 1  is a perspective view of a bathtub environment; 
       FIG. 2  is a sectional side view of a drain closure assembly associated with a bathtub taken along line  2 - 2  of  FIG. 1 ; 
       FIG. 3  is a front view of a sensor associated with a bathtub; 
       FIG. 4  is an enlarged sectional side view of an actuating member associated with a bathtub bottom drain; 
       FIG. 5  is an enlarged sectional side view of the actuating member of  FIG. 4  when activated; 
       FIG. 6  is an enlarged sectional side view of another embodiment of an actuating member associated with a bathtub bottom drain; and 
       FIG. 7  is an enlarged sectional side view of the actuating member of  FIG. 6  when activated. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to  FIGS. 1-7 , a conventional bathtub  10  has an upper overflow drain  12  and a lower drain  14  (also referred to as a bottom drain). The upper overflow drain  12  is located at one end wall  16  of the bathtub  10  for draining overflow fluids from the bathtub  10 . The lower drain  14  is located in the bottom  18  of the bathtub  10  for draining fluids from the bottom of the bathtub  10 . 
   The drain closure assembly  20  has a drain closure  32  associated with the lower drain  14  and an actuating member or mechanism  21  that is operatively associated with the drain closure device  32  to open and close the bottom drain  14 . The drain closure device  32  is of many types. As one example and as shown in  FIGS. 4 and 5  the drain closure device  20  has a stopper  38  with a stem  46  extending therefrom that is slidingly received in a nut portion  42  of a strainer body  30 . The stem  46  is positioned within a hollow sleeve  44 , wherein the shaft or a stem  46  that extends above and below the sleeve  44  and has an upper end connected to the stopper  38 , and a lower end that terminates in a head  52 . As another example, as shown in  FIGS. 6 and 7 , the drain closure device is a flap  73  that is movably connected to the bottom of the strainer body  30 . 
   The actuating member  21  is of many types such as a solenoid, a motor, or the like. In one example, the actuating member  21  comprises a solenoid piston  58  having a main body  60  with first and second magnets  62  positioned at opposite ends of the main body  60 . A conical tip  66  extends from one end of the main body  60  and engages the head  52  of the stem  46 . The actuating member  21  is slidably received within a housing  56  that is in communication with conduit  35  such that a rim  57  supports the main body  60 . The drain conduit  35  is of any configuration including those shown in  FIGS. 3-6 . Mounted around the housing  56  is a coil  68  that is located exterior to both the housing  56  and the conduit  35 . Extending from the coil  68  is an electrical contact  70  that connects the actuating member  21  to control device  28 . The control device  28  is connected to a power source  29  that provides an electrical charge to the coil  68 . The power source  29  is of many types including but not limited to an electrical outlet. A transformer (not shown) may optionally be inserted between the power source  29  and the drain closure assembly  20  to modify power provided thereto. The control device allows a user to selectively move the actuating member  21  to open and close drain  14 . 
   A sensor  23  is mounted in the bathtub  10  environment to sense the water level  24  contained within the bathtub  10 . The sensor  23  is located in a variety of positions such a below the overflow drain  12 , above the overflow drain  12 , in the end wall of the bathtub opposite end wall  16 , in the sidewalls of the bathtub  10 , or within the overflow drain  12 . The sensor  23  is of many types. One example, as shown in  FIG. 3 , includes first and second leads  25  and  26 . The first and second leads  25  and  26  are spaced such that when the water level  24  rises to fill the space between leads  25  and  26  a complete circuit is formed. The sensor  23  is connected to the control device  28  which is connected to the actuating member  21 . When a complete circuit is formed in sensor  23  a signal is communicated through the control device  28  that overrides the charge provided to the actuating member  21  to move the drain closure device  20  to an open position. 
   In operation, when a user wishes to fill the tub, a charge from the power source  29  is provided to the coil  68  to move the actuating member  21  which in turn moves the drain closure device  20  to a closed position to allow the tub to fill with fluid. As the water level rises to a point where the water level  24  completes the circuit between first and second leads  25  and  26  of sensor  23 , then a signal is sent from the sensor  23  to control device  28  which in turn interrupts the charge supplied to the drain closure assembly such that the actuating member  21  is activated and the drain closure device  20  is moved to an open position to allow water to drain from the tub  10 . In one embodiment, when the water level  24  falls such that a complete circuit is no longer formed in sensor  23 , the original charge from the power source  29  is restored and the drain closure assembly  20  returns to an open position. 
   With specific reference to  FIGS. 4 and 5 , one embodiment of the present invention is shown wherein the actuation member  21  is shown in the first position of use such that the drain closure device  32  is positioned against the bottom  18  of the bathtub. The solenoid piston  58  is shown positioned in the first position of use inside the activation switch  56 . The stem  46  is positioned in the downward position such that the head  52  thereof is situated on top of a protuberance  64  that is interconnected to the solenoid piston  58 . If the sensors indicate a situation where overflow is eminent, a signal is sent to the control device that sends an electrical current through the control device  70  into the coil  68 . As one of skill in the art will appreciate, energizing the coil  68  will create a magnetic field that interacts with the magnets  62  positioned on the main body  60  of the solenoid piston  58 . The repulsive effect of the interaction between the energized coil  68  and the magnets  62  will move the solenoid piston  58  relative to the stem  46 . Accordingly, the head  52  of the stem  46  will travel from the protuberance  64  and up the conical surface  66  of the sensor  58 . Preferably, a groove  72  is provided on the main body  60  that receives the head  52 . The movement of the solenoid piston  58  thus necessarily moves the stem  46  upwardly and moves the hollow sleeve  32  to a second, open position to allow fluid to flow from the bathtub and through the conduit  35 . 
   Referring now to  FIGS. 6 and 7 , yet another embodiment of the present invention is shown that employs a traditional strainer body  30  that is interconnected to a conduit  35 . This embodiment of the present invention, as previously described above, employs a flap  73  that is selectively opened and closed to allow fluid through the strainer body  30  into the conduit  35 . In a first position of use, as shown in  FIG. 7 , the solenoid piston  58  is positioned such that the flap  73  is closed so that water can fill the bathtub. When the liquid level in the bathtub reaches a predetermined depth, the coil  68  is energized, thereby creating a repulsive magnetic force that interacts with the magnet  62 , as described above. The repulsive magnetic force moves the solenoid piston  58  to a second position of use, which opens the flap  73 , thereby allowing fluid to travel from the bathtub and into the conduit  35 . 
   Therefore, as shown from the preceding description the stated objective has been accomplished.

Summary:
A bath drain assembly for use with a bathtub having a drain closure device mounted to a bottom drain and a movable actuating member engaging the drain closure device such that the drain closure device is toggled between open an closed positions when activated. A control device is in electronic communication with a sensor adapted to sense water level of fluid contained within the bathtub such that the drain closure device is moved to an open position via the actuating member when the sensor detects a given water level.