Patent Publication Number: US-9896830-B2

Title: Dual flush handle control

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent application is a continuation application of, and claims priority to, U.S. application Ser. No. 13/302,924, titled “DUAL FLUSH HANDLE CONTROL” and filed on Nov. 22, 2011, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Most dual flush toilet systems are provided as a package including a dual flush assembly and activation device to initiate operation of the dual flush assembly in one of the dual flush modes. In many instances, the activation control may not be preferred by the customer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a drawing of a dual flush toilet system with push button activation of a dual flush assembly according to various embodiments of the disclosure. 
         FIGS. 2A-2F  are drawings that provide various views of an activation assembly for push button activation of the dual flush assembly of  FIG. 1  according to various embodiments of the disclosure. 
         FIGS. 3A-3G  are drawings of a dual flush toilet system with rotational activation of the dual flush assembly of  FIG. 1  according to various embodiments of the disclosure. 
         FIGS. 4A-4F  are drawings of a dual-input activation assembly for use in the dual flush toilet system of  FIG. 1  according to various embodiments of the disclosure. 
         FIGS. 5A-5G  are drawings that provide various views of the dual-input activation assembly of  FIGS. 4A-4F  according to various embodiments of the disclosure. 
         FIGS. 6A-6D  are drawings that provide various views of an embodiment of a dual flush handle assembly that can be utilized in the activation assembly of  FIGS. 3A-3G  according to various embodiments of the disclosure. 
         FIGS. 7A-7C  are drawings that provide various views of the dual flush handle assembly of  FIGS. 6A-6D  in a neutral position. 
         FIGS. 8A-8C  are drawings that provide various views of the dual flush handle assembly of  FIGS. 6A-6D  in a position configured to initiate a partial flush in a toilet. 
         FIGS. 9A-9C  are drawings that provide various views of the dual flush handle assembly of  FIGS. 6A-6D  in a position configured to initiate a full flush in a toilet. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG. 1 , shown is a dual flush toilet system  100  including a dual flush assembly  103  and an activation assembly  106  to initiate operation of the dual flush assembly  103  in one of the dual flush modes: partial flush for liquids and full flush for solids. In the embodiment of  FIG. 1 , the activation assembly  106  includes a push button assembly  109  that is detachably connected to an actuation control box  113 . The actuation control box  113  is in communication with the dual flush assembly  103  through a cable assembly  116 , which is directly connected to the actuation control box  113  and the body of the dual flush assembly  103 . 
     Referring next to  FIGS. 2A-2F , the operation of the activation assembly  106  is illustrated. The push button assembly  109  is detachably connected to the actuation control box  113  through a shaft extension  203 , which is threaded to mount the push button assembly  109  to the tank of the toilet with a nut. In the embodiment of  FIGS. 2A-2F , the end  206  of the shaft extension  203  is engaged with the actuation control box  113  by a spring-loaded clip assembly  209 . By pressing the end of clip assembly  209 , the push button assembly  109  may be detached from the actuation control box  113 . The push button assembly  109  includes a first button  213  for activation of the quick flush mode with a reduced amount of water usage and a second button  216  for activation of the full flush mode using the standard amount of water. 
       FIG. 2C  illustrates a cross-sectional view of the activation assembly  106  of  FIG. 2A .  FIGS. 2A and 2C  show the actuation control box  113  in a neutral position without buttons  213  or  216  depressed. Depressing one of the buttons  213  or  216  extends a plunger  219  from the end of the shaft extension  203  into the actuation control box  113 . In the exemplary embodiment of  FIGS. 2C-D , extension of plunger  219  causes a cam  223  to rotate about a fixed point  226 , retracting a cable  229  into cable assembly  116  of  FIG. 1 . In this way, linear motion of the plunger  219  is converted into linear motion of cable  229  in cable assembly  116 . Depressing the first “quick flush” button  213  extends the plunger  219  to a predetermined intermediate position as illustrated in  FIG. 2E , while depressing the second “full flush” button  216  fully extends the plunger  219  as depicted in  FIGS. 2B and 2F . When the plunger  219  is retracted after the desired flush is initiated, cam  223  and cable  229  return to the neutral position depicted in  FIG. 2C . 
     With reference to  FIGS. 3A-3G , shown is a dual flush toilet system  100  including a dual flush assembly  103  and an activation assembly  306  to initiate operation of the dual flush assembly  103  in one of the dual flush modes: quick flush for liquids and full flush for solids. In the embodiment of  FIG. 3A , the activation assembly  306  includes a rotary handle assembly  309  that is detachably connected to an actuation control box  313 . The exemplary actuation control box  313  is in communication with the dual flush assembly  103  through a cable assembly  116 , which is connected to the actuation control box  313  and the body of the dual flush assembly  103 . 
     As illustrated in  FIG. 3B , the rotary handle assembly  309  includes a handle lever  319 , a mounting sleeve  323  and a shaft  326  ( FIG. 3C ), which extends through the mounting sleeve  323 . The rotary handle assembly  309  is detachably connected to actuation control box  313 . In the embodiment of  FIGS. 3A-3G , the end of the mounting sleeve  323  is engaged with the actuation control box  313  by a spring-loaded clip assembly  329 . By pressing the end of clip assembly  329 , the rotary handle assembly  309  may be detached from the actuation control box  313 . 
       FIG. 3C  provides a cross-sectional view of the actuation control box  313 . Rotational motion of rotary handle assembly  309  is converted into linear motion of cable  229  in cable assembly  116  by the actuation control box  313  through linkage assembly  316  and piston  333 , which is coupled to cable  229  and constrained within a guide channel. Full rotation of the rotary handle assembly  309  initiates a “full flush” of the dual flush assembly  103 , while rotation of the rotary handle assembly  309  to only an intermediate position initiates a “quick flush” of the dual flush assembly  103 . While the translation of rotational motion to linear motion by the exemplary actuation control box  313  is presented in terms of the linkage assembly  316  coupled to piston  333 , other means for translation of rotational motion to linear motion may also be utilized within the actuation control box  313 . 
     The operation of the exemplary activation assembly  306  with a rotary handle assembly  309  is now discussed with reference next to  FIGS. 3D-3G . When the actuation control box  313  is in a neutral position ( FIG. 3C ), the handle lever  319  is in a horizontal position with cable  229  partially retracted into the actuation control box  313 . Full rotation of the rotary handle assembly  309 , as depicted in  FIGS. 3D-3E , causes cable  229  to retract into the actuation control box  313 , initiating a “full flush” of the dual flush assembly  103 . 
     Restricting the rotation of rotary handle assembly  309 , and thus retraction of cable  229 , to an intermediate position provides for a “quick flush” of the dual flush assembly  103 .  FIGS. 3F-3G  illustrate operation of the rotary handle assembly  309  with restricted rotation. As depicted in  FIG. 3G , rotation of the handle lever  319  is translated from the shaft  326  through the linkage assembly  316  and piston  333  to linear movement of cable  229  until the intermediate position is reached. 
     It is noted that, while the rotary handle assembly  309  is described in relation to an actuation control box  313 , the rotary handle assembly  309  may be utilized in other applications that require a restricted rotational motion without the use of the actuation control box  313 . For example, if a toilet utilizes a flapper that is lifted by a chain, the amount of flapper lift may be restricted by the rotary handle assembly  309 . In one embodiment, a lever arm may engage with the end of the shaft  326  to lift the chain. Alternatively, rotation of the rotary handle assembly  309  may be sensed (either mechanically or electrically) to control an application. 
     With reference to  FIGS. 4A and 4B , shown is a dual-input activation assembly  406  that may be used in the dual flush toilet system  100  of  FIG. 1  according to various embodiments of the disclosure. The dual-input activation assembly  406  includes an activation control assembly  403  detachably connected to a dual-input actuation control box  413 . In the exemplary embodiment of  FIG. 4A , the activation control assembly  403  is a push button assembly  109  detachably connected to the dual-input actuation control box  413  through a linear input connection  416 . The push button assembly  109  includes the first button  213  for activation of the quick flush mode and the second button  216  for activation of the full flush mode. In a second configuration illustrated in  FIG. 4B , the activation control assembly  403  is a rotary handle assembly  409  detachably connected to the dual-input actuation control box  413  through a rotational input connection  419 .  FIG. 4C  illustrates dual-input activation assembly  406  with both a push button assembly  109  and a rotary handle assembly  409  detachably connected to the dual-input actuation control box  413 . 
     Referring now to  FIG. 4D , shown is an exploded view of the dual-input activation assembly  406 . The dual-input actuation control box  413  includes a cable anchor  423  that detachably connects one end of the cable  229  of cable assembly  116  (see e.g.,  FIGS. 5A-5G ). Cable anchor  423  is constrained within the dual-input actuation control box  413  by a linear guide path  426 . The dual-input actuation control box  413  also includes a dual-input cam  429  configured to translate activation motion of either the push button assembly  109  or the rotary handle assembly  409  into linear motion of the cable anchor  423 , and thus an attached cable  229  in cable assembly  116 . The dual-input actuation control box  413  is configured to allow the dual-input cam  429  to rotate about a rotational axis that is substantially perpendicular to the linear guide path  426 . 
     The push button assembly  109  may be detachably connected to the dual-input actuation control box  413  through the linear input connection  416 . In the embodiments of  FIGS. 4A-4D , the end  206  of the shaft extension  203  of the push button assembly  109  is engaged with the push actuation control box  113  by a spring-loaded clip assembly  209   a . By pressing the end of clip assembly  209   a , the push button assembly  109  may be detached from the dual-input actuation control box  413 . 
     The rotary handle assembly  409  may also be detachably connected to the dual-input actuation control box  413  through a rotational input connection  419 . Referring to  FIG. 4E , shown is an exploded view of the rotary handle assembly  409 . The rotary handle assembly  409  includes a handle lever  433 , and may include a handle button  436  and a mounting sleeve  439  through which the shaft  443  of the handle lever  433  extends. In the embodiments of  FIGS. 4A-4F , the end of the mounting sleeve  439  is engaged with the dual-input actuation control box  413  and may be detachably connected by a spring-loaded clip assembly  209   b  or other appropriate connection. By pressing the end of clip assembly  209   b , the rotary handle assembly  409  may be detached from the dual-input actuation control box  413 . 
     When detachably connected to the dual-input actuation control box  413 , the rotary handle assembly  409  engages with dual-input cam  429 . Referring now to  FIG. 4E , as the rotary handle assembly  409  is inserted (depicted as arrow  446 ) through the rotational input connection  419  ( FIGS. 4A-4E ), the end of the handle shaft  443  engages with a corresponding opening  449  in the dual-input cam  429 . In the embodiments of  FIGS. 4A-4F , the end of the shaft  443  of the handle lever  433  includes a spline that aligns with opening  449  to provide for torque transfer to the dual-input cam  429 . Other embodiments may utilize shaft end shapes such as, but not limited to, square, triangular, hexagonal, and keyed and a correspondingly shaped opening  449  in the dual-input cam  429 . 
     Next, operation of the dual-input activation assembly  406  is now discussed with reference next to  FIGS. 5A-5G .  FIGS. 5A-5C  illustrate the dual-input activation assembly  406  in a neutral position.  FIG. 5A  depicts the dual-input actuation control box  413  in the neutral position without either the first button  213  ( FIG. 4A ) for activation of the quick flush mode or the second button  216  ( FIG. 4A ) for activation of the full flush mode depressed. In addition, when the dual-input actuation control box  413  is in a neutral position as depicted in  FIG. 5B , the handle lever  433  is in a neutral position. In the embodiment of  FIG. 5B , the handle lever  433  is in a horizontal position.  FIG. 5C  provides a cutaway view of the dual-input actuation control box  413  in the neutral position. In the neutral position, the cable  229  is retracted in cable assembly  116  and the cable anchor  423  is at a neutral position in the linear guide path  426 . 
     Depressing one of the buttons  213  or  216  extends a plunger  219  ( FIGS. 5D and 5F ) from the end of the shaft extension  203  into the dual-input actuation control box  413 . In the exemplary embodiments of  FIGS. 5D and 5F , as the plunger  219  extends, the plunger  219  engages plunger arm  503  of the dual-input cam  429  causing the dual-input cam  429  to rotate about the rotational axis. The force provided through the plunger  219  is transferred through the dual-input cam  429  to the cable anchor  423  in the linear guide path  426  by an anchor arm  506 . In the embodiments of  FIGS. 5A-5G , the anchor arm  506  is configured to exert an initial breakaway force on the cable anchor  423 , followed by a reduced translation force. In one embodiment, the higher breakaway force is exerted at a breakaway point  509  of the anchor arm  506  on a breakaway shoulder  513  of the cable anchor  423 . As the cable anchor  423  moves along the linear guide path  426 , the dual-input cam  429  rotates about the rotational axis until the anchor arm  506  engages a translation pin  516  at a second position on the anchor arm  506 . 
     Further rotation of the dual-input cam  429  exerts a reduced translation force on the cable anchor  423  through the translation pin  516  because of an increased lever arm length. Anchor arm  506  disengages with the breakaway shoulder  513 , removing the breakaway force from the cable anchor  423 . Depressing the quick flush button  213  ( FIG. 4A ) extends the plunger  219  from the end of the shaft extension  203  to an intermediate quick flush position as illustrated in  FIG. 5D . Depressing the full flush button  216  ( FIG. 4A ) fully extends the plunger  219  from the end of the shaft extension  203  to a full flush position as illustrated in  FIG. 5F . 
     Counter clockwise rotation of the handle lever  433  produces a similar result. The torque transferred from the handle lever  433  to the dual-input cam  429  through shaft  443  and opening is exerted on the cable anchor  423 , initially as a breakaway force and subsequently as a reduced translation force as described above. Depressing handle button  436  before rotating handle lever  433  restricts the rotation of the activation control assembly  403 , to the intermediate quick flush position as illustrated in  FIG. 5E . Rotating the handle lever  433  without depressing the handle button  436  initiates a full flush of the dual flush assembly  103  by allowing the handle lever  433  to be rotated in a counter clockwise direction beyond the quick flush restriction point.  FIG. 5G  illustrates the handle lever  433  rotated to the full flush position. 
     Referring next to  FIGS. 6A-6D , shown is one example of a dual flush handle assembly  600  according to various embodiments of the present disclosure. The dual flush handle assembly  600  may be used to initiate a partial flush and/or a full flush of a toilet. To this end, the dual flush handle assembly  600  may be in communication with, for example, the actuation control box  313  ( FIG. 3 ), the dual-input activation assembly  406  ( FIGS. 4A-4F ), or other dual flush activation control mechanisms. As further non-limiting examples, the dual flush handle assembly  600  may be used with various embodiments disclosed in co-pending U.S. Patent Application entitled “Dual Flush Activation” filed on Jan. 7, 2011 and assigned application Ser. No. 12/986,729, which is incorporated by reference herein in its entirety. 
       FIGS. 6A-6B  show exploded views of one embodiment, among others, of the dual flush handle assembly  600 . The dual flush handle assembly  600  includes a first handle lever  603 , a second handle lever  606 , a bushing  609 , a damper  613 , a first spring  616 , a second spring  619 , a first retaining element  623 , a second retaining element  626 , and possibly other components not discussed in detail herein. 
     The first handle lever  603  is shaped to be nested within the second handle lever  606 . In this sense, the first handle lever  603  and second handle lever  606  are formed to facilitate at least a portion of the first handle lever  603  “fitting” within a portion of the second handle lever  606 . The second handle lever  606  may fit within a profile of the first handle so as to promote the appearance of a single handle. Accordingly, the dual flush handle assembly  600  may present an appearance of a conventional toilet flush lever, while providing the functionality of a dual flush handle control. 
     As will later be described, the first handle lever  603  and second handle lever  606  may be configured to rotate co-axially about a common axis in order to initiate a partial flush and/or a full flush of a toilet. The first handle lever  603  may be limited in rotation by a certain amount. The second handle lever  606  may be limited in rotation by an amount that differs from the rotation of the first handle lever  603 . In this sense, the rotation of the first handle lever  603  and rotation of the second handle lever  606  may overlap at least partially. Further, it is emphasized that initiating a partial flush or a full flush may be caused by rotating the first handle lever  603  or second handle lever  606 , respectively, in the same direction of rotation. 
     The first handle lever  603  is configured to rotate about an axis by a predetermined angle of rotation. To this end, the first handle lever  603  includes a projection  629  and post  633 , both extending from a toilet-facing surface of the first handle lever  603 . In various embodiments, the projection  629  may comprise tabs, pins, knobs, detents, or other types of projections. The post  633  includes a post groove  636  to facilitate retaining the first handle lever  603  to the dual flush handle assembly  600  as will be later described. The first handle lever  603  may also include one or more indicators  639  to denote to a user that the function of the first handle lever  603  is to initiate a partial flush of a toilet. 
     The second handle lever  606  is also configured to rotate about an axis by a predetermined angle of rotation. It is emphasized that the second handle lever  606  may rotate by a predetermined angle of rotation that is different than the angle of rotation of the first handle lever  603 . The second handle lever  606  includes a slot  643 , a stem  646 , one or more indicators  639 , and possibly other features not discussed in detail herein. 
     As best shown in  FIGS. 6B and 6C , the slot  643  is disposed in a wall of the second handle lever  606  and is configured to receive the projection  629 . The stem  646  extends from both the outward and toilet-facing surfaces of the second handle lever  606 . In alternative embodiments, the stem  646  may extend from only one of the outward or toilet-facing surfaces of the second handle lever  606 . 
     The stem  646  includes a bore  649  extending from the outward end of the stem  646 . The bore  649  is configured to receive the post  633  of the first handle lever  603 . Although the stem  646  shown in  FIGS. 6A-6D  is configured to receive the post  633 , the post  633  in alternative embodiments may be configured to receive the stem  646 . 
     The portion of the stem  646  extending from the interior end of the second handle lever  606  includes a stem slot  653  configured to accommodate the first retaining element  623 . At the distal end of the interior portion of the stem  646  is a stem groove  656 . The stem groove  656  is configured to receive the second retaining element  626  and facilitates securing the second handle lever  606  to the bushing  609 . 
     The bushing  609  is configured to extend through an opening in a wall of a toilet tank. The bushing  609  includes a passage  659 , a stop  663 , a lip  665 , a rectangular segment  666 , a threaded segment  669 , and possibly other features not discussed in detail herein. 
     The passage  659  extends longitudinally through the bushing  609  and is configured for the stem  646  of the second handle lever  606  to pass at least partially through the bushing  609 . The stop  663  extends from the bushing  609  and is configured to extend through the slot  643  of the second handle lever  606  and to abut the projection  629  of the first handle lever  603  as will be later described. 
     The lip  665  of the bushing  609  is configured to abut an exterior surface of a toilet tank. The rectangular segment  666  is configured to be secured in a rectangular opening in the toilet tank wall, thereby preventing rotational movement of the bushing  609  with respect to the toilet tank wall. The threaded segment  669  of the bushing  609  is configured to receive an appropriately threaded nut that abuts an interior surface of the toilet tank wall, thereby preventing translational movement of the bushing  609  with respect to the toilet tank. 
     The damper  613  may be disposed between the first handle lever  603  and second handle lever  606 . In the embodiment shown in  FIGS. 6A-6D , the damper  613  is attached to the first handle lever  603 . However, in alternative embodiments, the damper  613  may be attached to the second handle lever  606 . Best shown in  FIG. 6B , the damper includes a lip  676  to facilitate retaining the damper  613  in an appropriate aperture of the first handle lever  603 . In alternative embodiments, the damper  613  may be attached using, for example, an adhesive or other attachment mechanism. 
     The damper  613  may be formed of various cushioning materials, such as rubber, nylon, foam, or other materials. By being disposed between the first handle lever  603  and second handle lever  606 , the damper  613  may prevent or reduce sound caused by the first handle lever  603  abruptly contacting the second handle lever  606 . Additionally, the damper  613  may provide a cushioned sensation when using dual flush handle assembly  600 . 
     The first spring  616  may be configured to provide a bias force that retains the first handle lever  603  towards the second handle lever  606  when in a neutral position. To this end, the first spring  616  may be disposed between the first handle lever  603  and second handle lever  606 , with the first spring  616  being around the post  633 . The ends of the first spring  616  may be retained, for example, in appropriate openings in the first handle lever  603  and/or second handle lever  606  as is appreciated. 
     In other embodiments, the function of the first spring  616  may be incorporated into the damper  613 . To this end, the damper  613  may be formed of a spring-like material and attached to the first handle lever  603  and second handle lever  606 . 
     The second spring  619  is configured to provide a bias force that facilitates returning the second handle lever  606  and/or first handle lever  603  to a neutral position after initiating a flush. To this end, the second spring  619  may be disposed between the second handle lever  606  and bushing  609 , with the second spring  619  being around the stem  646  of the second handle lever  606 . The ends of the second spring  619  may be retained, for example, in appropriate holes in the second handle lever  606  and/or bushing  609 . 
     The second spring  619  may also facilitate installation of the dual flush handle assembly  600 . In this sense, the second spring  619  may bias the first handle lever  603  and second handle lever  606  to be in an approximately horizontal position when the bushing  609  is inserted into an opening in the toilet tank wall and prevented from rotating with respect to the tank wall. In other words, with the bushing  609  inserted into the tank wall and fixed from rotating, the second spring  619  may facilitate the first handle lever  603  and second handle lever  606  being biased in an approximately horizontal position. 
     Although the first spring  616  and second spring  619  are shown as being coil springs, other types of springs may be used in accordance with the present disclosure. For example, flat springs, leaf spring, rubber bands, or any other type of spring element may be used. Further, it is understood that a first spring  616  and/or second spring  619  may be omitted in various embodiments. 
     The first retaining element  623  is configured to retain the post  633  within the stem  646 . To this end, the first retaining element  623  may insert at least partially into the stem slot  653  and clip to the post groove  636 . Thus, the first retaining element  623  may retain the first handle lever  603  to the second handle lever  606  in a lateral position, while facilitating rotation of the first handle lever  603  with respect to the second handle lever  606 . 
     In a similar fashion, the second retaining element  626  is configured to retain the stem  646  within the bushing  609 . To this end, with the stem groove  656  extending through the passage  659  of the bushing  609 , the second retaining element  626  may clip to the stem groove  656 . Thus, the second retaining element  626  may retain the second handle lever  606  to the bushing  609  in a lateral position, while facilitating rotation of the second handle lever  606  and/or first handle lever  603  with respect to the bushing  609 . 
     It is understood that other methods of retaining the first handle lever  603 , second handle lever  606 , and bushing  609  may be used. For example, instead of the stem  646  extending from the second handle lever  606 , the stem  646  may extend from the bushing  609 . In such a case, the second handle lever  606  and/or first handle lever  603  may include appropriate mechanisms for attachment as can be appreciated. 
     In addition, it is understood that other mechanisms of restricting the rotation of the first handle lever  603  and/or second handle lever  606  may be used. For example, although embodiment of  FIGS. 6A-6D  shows the first handle lever  603  comprising the projection  629  and the second handle lever  606  comprising the slot  643 , the second handle lever  606  may comprise a projection  629  in various alternative embodiments. Additionally, the projection  629  may extend from the bushing  609  in various other embodiments. Even further, the first handle lever  603  and/or bushing  609  may comprise the slot  643 . 
     Next, a description of the general operation of the dual flush handle assembly  600  is provided.  FIGS. 7A-7C, 8A-8C, and 9A-9C  show progressions of the dual flush handle assembly  600  being in a neutral position, initiating a partial flush (i.e., “quick flush”), and initiating a full flush, respectively. 
     With reference to  FIGS. 7A-7C , shown is the dual flush handle assembly  600  in a neutral position according to various embodiments of the present disclosure. The neutral position shown is the position to which the dual flush handle assembly  600  returns after a flush has been initiated. As shown in  FIGS. 7B and 7C , the reference line A denotes the position at which a portion of the first handle lever  603  and second handle lever  606  rest while in the neutral position. 
     As shown in  FIGS. 7A-7C , the projection  629  of the first handle lever  603  ( FIGS. 6A-6D ) is positioned within the slot  643  of the second handle lever  606 . Also, the stop  663  of the bushing  609  is positioned within the slot  643  of the second handle lever  606 . As best shown in  FIGS. 7B and 7C , there is a space  703  between the stop  663  and the projection  629 . Further, there is a space  706  between the projection  629  and an edge of the slot  643 . Additionally, the stop  663  of the bushing  609  is engaged with the opposite edge of the slot  643 . 
     Turning now to  FIGS. 8A-8C , shown is the dual flush handle assembly  600  in a position configured to initiate a partial flush of a toilet. The dual flush handle assembly  600  may arrive in this position, for example, by a user pressing on the first handle lever  603 . Rotating the first handle lever  603  pushes against the second handle lever  606  causing the second handle lever  606 , and thus the stem  646 , to rotate as well. The rotation of the first handle lever  603  is limited by the projection  629  of the first handle lever  603  making contact with the stop  663  of the bushing  609 . By rotating the first handle lever  603  by the predetermined amount, the stem  646  rotates to initiate a partial flush, for example, through the actuation control box  313  ( FIGS. 3A-3G ) as described above. 
     As shown in  FIGS. 8B and 8C , the angle α denotes the angle of rotation that the first handle lever  603  and second handle lever  606  have rotated from the neutral position (denoted by reference line A) to the position for initiating a partial flush (denoted by reference line B). By rotating by the angle α, the stop  663  now abuts the projection  629  of the first handle lever  603 . Thus, the angle of rotation α is limited by the projection  629  engaging the stop  663 . With the projection  629  engaging the stop  663 , there is a space  703  between the stop  663  and an edge of the slot  643 . Additionally, the space  706  between the projection  629  and opposite end of the slot  643  still exists. 
     After a partial flush has been initiated, the dual flush handle assembly  600  may automatically return to the neutral position shown in  FIGS. 7A-7C . To this, end, the second spring  619  or any other mechanism may cause the dual flush handle assembly  600  to return to the neutral position. 
     Turning to  FIGS. 9A-9C , shown is the dual flush handle assembly  600  in a position configured to initiate a full flush of a toilet. The dual flush handle assembly  600  may arrive in this position, for example, by a user pressing the second handle lever  606 . By pressing on the second handle lever  606 , the first spring  616  ( FIGS. 6A-6D ) cause the first handle lever  603  to rotate in conjunction with the second handle lever  606  by angle α until the projection  629  of the first handle lever  603  contacts the stop  663  of the bushing  609 . While the first handle lever  603  stops rotating at angle α, the second handle lever  606  may continue to rotate until the edge of the slot  643  of the second handle lever  606  contacts the tab of the first handle lever  603 . Thus, the stem  646  may rotate to initiate a full flush of a toilet, for example, via the actuation control box  313  ( FIGS. 3A-3G ). 
     As shown in  FIGS. 9B and 9C , the angle α denotes the angle of rotation that the first handle lever  603  has rotated from the neutral position (denoted by reference line A). Similarly, the angle β shows the angle of rotation that the second handle lever  606  has rotated from the neutral position (denoted by reference line A) to the full flush position (denoted by reference line C). 
     As best shown in  FIGS. 9B and 9C , the stop  663  abuts the projection  629 , and the projection  629  engages the edge of the slot  643  of the second handle lever  606 . Thus, the slot  643  in conjunction with the projection  629  acts to define the predetermined angle β of rotation. With the dual flush handle assembly  600  in the position configured to initiate a full flush, the space  706  ( FIG. 8A-8C ) between the projection  629  and edge of the slot  643  no longer exists. Additionally, the space  703  between the stop  663  and opposite edge of the slot  643  has widened. 
     After a full flush has been initiated, the dual flush handle assembly  600  may automatically return to the neutral position shown in  FIGS. 7A-7C . To this end, the second spring  619  or any other mechanism may return the dual flush handle assembly  600  to the neutral position. In alternative embodiments, the dual flush handle assembly  600  may return to the neutral position using other mechanisms. As non-limiting examples, the dual flush handle assembly  600  may return to the neutral position due its own weight, from a flush valve dropping due to a drop in water level in the toilet tank, from a spring force inside the activation control box  313  ( FIG. 3 ), from a spring force associated with a flush valve, or from any other mechanism. 
     It is noted that ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a concentration range of “about 0.1% to about 5%” should be interpreted to include not only the explicitly recited concentration of about 0.1 wt % to about 5 wt %, but also include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range. The term “about” can include ±1%, ±2%, ±3%, ±4%, ±5%, ±6%, ±7%, ±8%, ±9%, or ±10%, or more of the numerical value(s) being modified. In addition, the phrase “about ‘x’ to ‘y’” includes “about ‘x’ to about ‘y’”. 
     It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.