Dual flush device for toilets

Abstract

A dual flush device comprises a mounting structure and a float to retrofit single flush toilets to dual flush toilets. The mounting structure is attached to an overflow tube and connected to the float with a vertical bar along which the float can move vertically downward or upward with the water level in the toilet tank. The float includes a water-tight container and a bottom part screwed into the bottom of the container. The vertical length of the float is adjustable by rotating the bottom part either away or toward the container. Several embodiments of the mounting structure and float are invented to accommodate various toilet models. The dual flush device operates with a flapper valve and a single flush handle assembly and maintains the modular design of conventional toilets. The float will prematurely close the flapper valve in a partial flush using less water than in a full flush.

What is claimed is: 
     
         1 . A dual flush device for toilets, the dual flush device comprising:
 a mounting structure configured to attach and fasten to an overflow tube in a toilet tank;   a float connected to said mounting structure through a vertical bar of said mounting structure;   wherein said float is configured to move vertically downward following a falling water level in the tank to prematurely close a flapper valve in a partial flush using less volume of water than in a full flush;   wherein said float is configured to move vertically upward following a rising water level during tank refill;   wherein said dual flush device is configured to work with a single flush handle assembly and said flapper valve;   whereby said dual flush device maintains a modular design of conventional toilets to keep the inherent convenience and economy of maintenance and part replacement.   
     
     
         2 . The dual flush device of  claim 1 , wherein said mounting structure comprises a main body, said vertical bar, and external parts integrally attached to said main body, including an upper horizontal extension with an opening configured to be inserted with said vertical bar, a lower horizontal extension with an opening in vertical alignment with said opening on said upper horizontal extension and configured to be inserted with said vertical bar, an L-shaped vertical block extending from a bottom of said main body to a height below a top surface of said main body, and a protruding section with a threaded hole inserted with a hand-tightening nut, wherein said opening on said upper horizontal extension and said opening on said lower horizontal extension are sized to tightly fit and hold said vertical bar in place, and wherein said upper horizontal extension and said lower horizontal extension of said mounting structure limit the vertical movement of said float. 
     
     
         3 . The dual flush device of  claim 2 , wherein each of a first embodiment of said mounting structure and a second embodiment of said mounting structure has the main body of a double-wall cylindrical structure that has an outer cylindrical wall and a shorter inner cylindrical wall with an in-between gap, wherein said outer cylindrical wall and said inner cylindrical wall are integrally sealed at a top with a ring-shaped horizontal wall, wherein said outer cylindrical wall has an inside diameter slightly larger than an outside diameter of said overflow tube, wherein said inner cylindrical wall has an outside diameter slightly smaller than an inside diameter of said overflow tube, and wherein said double-wall cylindrical structure has a top notch with a small piece of said outer wall and an adjacent piece of the ring-shaped top horizontal wall removed to expose any parts behind. 
     
     
         4 . The dual flush device of  claim 3 , wherein each of said first embodiment of said mounting structure and said second embodiment of said mounting structure is attached to said overflow tube by placing said double-wall cylindrical structure over said overflow tube and lowering it until a top section of said overflow tube is inserted into said gap between said outer cylindrical wall and said inner cylindrical wall and said double-wall cylindrical structure firmly rests on a top of said overflow tube, and wherein each of said first embodiment of said mounting structure and said second embodiment of said mounting structure is fastened at a proper horizontal location above said flapper valve by tightening said hand-tightening nut of said mounting structure. 
     
     
         5 . The dual flush device of  claim 4 , wherein said first embodiment of said mounting structure further has a refill tube holder that is integrally attached to a top surface adjacent to a top opening of said double-wall cylindrical structure for fastening a refill tube above said top opening. 
     
     
         6 . The dual flush device of  claim 3 , wherein a third embodiment of said mounting structure has the main body of a hollow cylinder with a circular central opening at an inside diameter slightly larger than said outside diameter of said overflow tube, wherein said hollow cylinder has a top notch with a small piece of a cylindrical wall removed to expose any parts behind, wherein said third embodiment of said mounting structure is supported at a bottom by a clamp-like device fastened at a proper axial location to said overflow tube, wherein said third embodiment of said mounting structure is attached to said overflow tube by lowering said hollow cylinder of said mounting structure to insert a top section of said overflow tube inside until firmly resting on said clamp-like device, wherein said third embodiment of said mounting structure is fastened to said overflow tube at a proper horizontal location above said flapper valve by tightening said hand-tightening nut of said mounting structure. 
     
     
         7 . The dual flush device of  claim 6 , wherein a fourth embodiment of said mounting structure has a main body of a single-wall cylindrical structure that comprises a cylindrical wall with a circular central opening integrally attached at a top to a ring-shaped horizontal wall that has a same outside diameter but a somewhat smaller inside diameter in comparison to said cylindrical wall, wherein said cylindrical wall has an inside diameter slightly larger than said outside diameter of said overflow tube and said ring-shaped horizontal wall has an inside diameter somewhat smaller than said inside diameter of said overflow tube, wherein said single-wall cylindrical structure has a top notch by removing a small piece of said cylindrical wall and an adjacent piece of the ring-shaped top horizontal wall to expose any parts behind, wherein said fourth embodiment of said mounting structure is attached to said overflow tube by placing it over said overflow tube and inserting a top section of said overflow tube inside said single-wall cylindrical structure until the ring-shaped top horizontal wall firmly rests on a top of said overflow tube, and wherein said fourth embodiment of said mounting structure is fastened to said overflow tube at a proper horizontal location above said flapper valve by tightening said hand-tightening nut of said mounting structure. 
     
     
         8 . The dual flush device of  claim 7 , wherein a fifth embodiment of said mounting structure has a main body of a partial cylindrical structure with a vertical keyhole inside extending from a bottom of said partial cylindrical structure to an underside of a sealed top wall of said partial cylindrical structure, wherein said fifth embodiment of said mounting structure uses an adapter that comprises a clamp for fastening to said overflow tube and a vertical key integrally attached to an outer surface of said clamp, wherein said vertical key of said adapter is configured to tightly fit into said vertical keyhole of said partial cylindrical structure, wherein said adapter is attached and fastened to said overflow tube by sliding said clamp of said adapter around said overflow tube to a proper axial and horizontal location and tightening said clamp, and wherein said fifth embodiment of said mounting structure is attached and fastened to said overflow tube by placing said vertical keyhole of said main body over said vertical key of said adapter and lowering it until said vertical key of said adapter is fully inserted into said keyhole of said partial cylindrical structure. 
     
     
         9 . The dual flush device of  claim 2 , wherein said float comprises a watertight container with all watertight walls including a sealed top cover to provide buoyancy in water and a bottom part vertically attached to said container, wherein said container includes an external horizontal extension with an opening to be loosely inserted with said vertical bar of said mounting structure, wherein said container further includes an external vertical channel enclosed by two side walls configured to engage said L-shaped vertical block of said mounting structure, wherein an engagement of said vertical channel of said float with said L-shaped vertical block of said mounting structure will place said opening on said external horizontal extension of said float between and in a vertical alignment with said opening on said upper horizontal extension and said opening on said lower horizontal extension of said mounting structure to allow an insertion of said vertical bar into all three openings, wherein the insertion of said vertical bar into the three openings connects said float to said mounting structure to form said dual flush device, wherein said float is configured to slide along said vertical bar and said L-shaped vertical block of said mounting structure in a toilet flush, and wherein said float will move vertically downward with falling water level in the tank in said partial flush and will move vertically upward with rising water level during tank refill. 
     
     
         10 . The dual flush device of  claim 9 , wherein said container of said float further includes a watertight, internal vertical block and optional weights on a bottom wall, wherein there is a threaded hole inside said internal vertical block extending vertically from a bottom of said container to a location below a sealed top wall of said vertical block, and wherein said optional weights on said bottom wall of said container can be replaced with weights integrally built into the container walls. 
     
     
         11 . The dual flush device of  claim 10 , wherein an embodiment of said bottom part of said float comprises a vertical threaded rod integrally attached to an elongate bottom head, wherein said embodiment of said bottom part is configured to be vertically screwed into said threaded hole inside said internal vertical block of said container, and wherein an embodiment of said float comprises said container and said embodiment of said bottom part screwed into said container. 
     
     
         12 . The dual flush device of  claim 11 , wherein another embodiment of said bottom part of said float comprises a vertical threaded rod integrally attached to a bent elongate bottom head with multiple bends, wherein said another embodiment of said bottom part is configured to be vertically screwed into said threaded hole inside said internal vertical block of said container, and wherein another embodiment of said float comprises said container and said another embodiment of said bottom part screwed into said container. 
     
     
         13 . The dual flush device of  claim 12 , wherein a vertical length of said float is adjustable by varying an insertion length of said bottom part into said threaded hole inside the float container, wherein said vertical length of said float is increased by rotating said bottom part away from said container and is decreased by rotating said bottom part toward said container, wherein an increase in said vertical length of said float will in general prematurely close said flapper valve earlier to lead to less volume of water used in said partial flush, wherein a decrease in said vertical length of said float will in general prematurely close said flapper valve later to lead to more volume of water used in said partial flush, and wherein the length-adjustable float of said dual flush device enables a user to preselect a wide range of water usage in said partial flush from removing liquid wastes to removing a fair load of solid wastes. 
     
     
         14 . A dual flush device for toilets, the dual flush device comprising:
 a mounting structure including a main body, a vertical bar, and external parts integrally attached to said main body; and   a float including a watertight container with a sealed top cover, an external horizontal extension with an opening integrally attached to an outer wall of said container, an external vertical channel enclosed by two side walls of said container, and a bottom part inserted into said container;   wherein said external parts of said mounting structure include an upper horizontal extension with an opening, a lower horizontal extension with an opening vertically below said opening on said upper horizontal extension, an L-shaped vertical block, and a protruding section with a threaded hole inside to fit a hand-tightening nut;   wherein said external vertical channel of said float is configured to engage said L-shaped vertical block of said mounting structure and the engagement is configured to position said opening on said external horizontal extension of said float vertically between and in alignment with said opening on said upper horizontal extension and said opening on said lower horizontal extension of said mounting structure;   wherein said float is connected to said mounting structure by sequentially inserting said vertical bar into said opening on said upper horizontal extension of said mounting structure, said opening on said external horizontal extension of said float, and said opening on said lower horizontal extension of said mounting structure;   wherein said float is configured to move vertically downward along said vertical bar and said L-shaped vertical block of said mounting structure following falling water level in a toilet tank in a partial flush;   wherein said float is configured to move vertically upward along said vertical bar and said L-shaped vertical block of said mounting structure following rising water level during tank refill;   wherein vertical movement of said float is limited by said mounting structure;   wherein said mounting structure is configured to attach and fasten to an overflow tube in a toilet tank;   wherein said dual flush device is configured to operate with a conventional single flush handle assembly and a flapper valve in the tank;   whereby said dual flush device maintains a modular design of conventional toilets to keep the inherent convenience and economy of maintenance and part replacement.   
     
     
         15 . The dual flush device of  claim 14 , wherein an embodiment of said mounting structure has the main body of a double-wall cylindrical structure that has an outer cylindrical wall and a shorter inner cylindrical wall with an in-between gap, wherein said outer cylindrical wall and said inner cylindrical wall are integrally sealed at a top with a ring-shaped horizontal wall, wherein said double-wall cylindrical structure has a top notch by removing a small piece of said outer cylindrical wall and a small piece of the adjacent top horizontal wall to expose any parts behind, wherein said outer cylindrical wall has an inside diameter slightly larger than an outside diameter of said overflow tube, wherein said inner cylindrical wall has an outside diameter slightly smaller than an inside diameter of said overflow tube, wherein said mounting structure further includes a refill tube holder integrally attached to a top surface of said double-wall cylindrical structure for fastening a refill tube above a top opening, wherein said mounting structure is attached to said overflow tube by placing said in-between gap of said double-wall cylindrical structure over said overflow tube and lowering said mounting structure until it firmly rests on a top of said overflow tube, and wherein said mounting structure is fastened to said overflow tube at a proper horizontal location above said flapper valve by tightening said hand-tightening nut. 
     
     
         16 . The dual flush device of  claim 15 , wherein another embodiment of said mounting structure has the main body of a hollow cylinder with a circular central opening at an inside diameter slightly larger than said outside diameter of said overflow tube, wherein said hollow cylinder has a top notch by removing a small piece of a cylindrical wall to expose any parts behind, wherein a clamp-like device is fastened to said overflow tube at a proper axial location for supporting said mounting structure, wherein said mounting structure is attached to said overflow tube by sliding said hollow cylinder over said overflow tube until it firmly rests on said clamp-like device, and wherein said mounting structure is fastened to said overflow tube at a proper horizontal location above said flapper valve by tightening said hand-tightening nut. 
     
     
         17 . The dual flush device of  claim 16 , wherein a further embodiment of said mounting structure has the main body of a single-wall cylindrical structure integrally attached at a top to a ring-shaped top horizontal wall that has a same outside diameter but a smaller inside diameter compared to said single-wall cylindrical structure, wherein said single-wall cylindrical structure has an inside diameter slightly larger than said outside diameter of said overflow tube, wherein said ring-shaped top horizontal wall has an inside diameter somewhat smaller than said inside diameter of said overflow tube, wherein said single-wall cylindrical structure has a top notch by removing a small piece of the cylindrical wall and an adjacent piece of said ring-shaped top horizontal wall to expose any parts behind, wherein said mounting structure is attached to said overflow tube by sliding said single-wall cylindrical structure over said overflow tube until said ring-shaped top horizontal wall firmly rests on a top of said overflow tube, and wherein said mounting structure is fastened to said overflow tube by tightening said hand-tightening nut after setting said mounting structure at a proper horizontal location above said flapper valve. 
     
     
         18 . The dual flush device of  claim 14 , wherein said container of said float contains a watertight, internal vertical block with a sealed top wall and optional weights, wherein said internal vertical block has a threaded hole inside that extends vertically from an underside of a bottom wall of said container to an underside of said sealed top wall, wherein an embodiment of said bottom part of said float comprises a vertical threaded rod integrally attached to an elongate bottom head, wherein another embodiment of said bottom part comprises a vertical threaded rod integrally attached to a bent elongate bottom head with multiple horizontal bends, wherein each embodiment of said bottom part is configured to screw into said threaded hole inside said internal vertical block of said container, and wherein said optional weights inside said container can be integrally built into container walls. 
     
     
         19 . The dual flush device of  claim 18 , wherein a vertical length of said float is adjustable, wherein said vertical length can be increased by rotating said bottom part away from said container or decreased by rotating said bottom part toward said container, wherein said vertical length of said float influences a volume of water used in said partial flush, wherein a longer vertical length of said float will generally provide less volume of water in said partial flush by prematurely closing said flapper valve earlier, wherein a shorter vertical length of said float will generally provide more volume of water in said partial flush by prematurely closing said flapper valve later, and wherein the length-adjustable float of said dual flush device will enable a user to preselect a wide range of water usage in said partial flush from removing liquid wastes to removing a fair load of solid wastes.