Description:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)

&

THE PATENTS RULE, 2003

COMPLETE SPECIFICATION
[See Section 10, Rule 13]

A FLUSHING ASSEMBLY FOR A DUAL FLUSH CISTERN;

THE SUPREME INDUSTRIES LTD., A COMPANY INCORPORATED UNDER THE INDIAN COMPANIES ACT, 1913, WHOSE ADDRESS IS 4TH FLOOR, “ANTARIKSHA SIGNATURES”, BEHIND NYATI BULILDING, RADHA CHOWK, NEAR RADHA HOTEL 105/1/1/4, BANER, PUNE- 411045, MAHARASHTRA, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

TECHNICAL FIELD OF THE INVENTION
The present invention relates to toilet flushing systems and more particularly, to a dual flush cistern and a flushing assembly thereof.
BACKGROUND OF THE INVENTION
Water conservation includes avoiding wastage along with the adequate consumption of the available water. The water used in flushing toilets is one of the significant sources of water consumption. Toilet cisterns generally have a fixed volume water cistern, the full content of which is discharged to the bowl when flushed. In many instances, a full discharge is not required and effective flushing of the toilet bowl could be achieved by discharging a smaller volume from the cistern. In this way wastage of water could be minimized achieving reduced water consumption.
Current state of art includes a number of dual flush cistern devised with a view to providing the user with a choice between a full flush, in which the full content of the cistern is discharged into the bowl, and a partial flush in which only part of the cistern content is discharged. Many of the known dual flush valves are either complicated and expensive to manufacture or are unreliable in operation. Further, the current art includes the technologies for converting a single flush cistern into dual flush cistern. However, such technologies include replacing the single lever and single stem assembly of the single flush cistern by two levers and two containers having separate stems for two types of flushing mode.
Accordingly, there is a need to provide a dual flushing cistern having full and reduced flushing options and that can be installed in existing single flush cisterns.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a flushing assembly for a dual flush cistern. The flushing assembly includes a lever is positioned outside the cistern for operating the cistern. A flushing stem is connected to the lever positioned inside the cistern through a common actuating lever for lifting the stem with a float. A buoyancy force acts on the float that determines the time for shutting off the flushing of water from the cistern. A switch is operably attached on the lever. The switch includes a stopper configured at rear side of the switch for engaging or disengaging with the flushing stem to define full flushing and reduced flushing conditions of the cistern by allowing a total lifting or a partial lifting of the flushing stem. A container having a central hole for passing the stem and defining an annular space between the stem and the central hole in the container through which water from the container flushes. An off-centered hole is configured at bottom portion of the container for additional flushing of water from the container. A valve is attached at a bottom of the stem to restrict the flow of water through an outlet of the cistern. A bush is attached on a surface of the valve. The bush closes the off-centered hole when the flushing stem is lifted full and maintains open when the flushing stem is lifted partial for changing buoyancy force acting on the float thereby setting a full or reduced flush thereby setting a full or reduced flush condition. The switch includes a stopper configured at rear side of the switch for engaging or disengaging with the flushing stem thereby setting a full or reduced flush condition. The stopper engages with the flushing stem through a first slot configured in the lever and a second slot configured on the cistern. An inner profile of the float matches with the outer profiled of the stem. An outer profile of the float is in slidable contact with the inner profiled of the container. The diameter of the bush coincides with the diameter of the hole to restrict the movement of the float to restrict the movement of the float. The diameter of the off-centered hole depends on amount of water to be flushed in reduced flushing condition compared to full flush condition. The diameter of the hole is approximately equals to 0.25 times diameter of the outlet for reduced flushing. The height by which stem is lifted upwards in reduced flush is approximately 60 to 75 % value of height in full flush condition. Time taken to discharge water from the container is directly proportional to square root of head of water level within container. Time taken to discharge water from the container is inversely proportional to square value of diameter of the hole. Time taken to discharge water from the container is inversely proportional to area of gap between diameter of the stem and diameter of hole.
In another aspect, the present invention relates to a dual flush cistern that includes a fill valve for filling water up-to a desired level in a cistern. a lever positioned outside the cistern for operating the cistern. A flushing stem is connected to the lever positioned inside the cistern through a common actuating lever for lifting the stem with a float. A buoyancy force acts on the float that determines the time for shutting off the flushing of water from the cistern. A switch is operably attached on the lever. The switch includes a stopper configured at rear side of the switch for engaging or disengaging with the flushing stem to define full flushing and reduced flushing conditions of the cistern by allowing a total lifting or a partial lifting of the flushing stem. A container having a central hole for passing the stem and defining an annular space between the stem and the central hole in the container through which water from the container flushes. An off-centered hole is configured at bottom portion of the container for additional flushing of water from the container. A valve is attached at a bottom of the stem to restrict the flow of water through an outlet of the cistern. A bush is attached on a surface of the valve. The bush closes the off-centered hole when the flushing stem is lifted full and maintains open when the flushing stem is lifted partial for changing buoyancy force acting on the float thereby setting a full or reduced flush thereby setting a full or reduced flush condition.
In yet another aspect, the present invention teaches to convert the single flush cistern into dual flush cistern. A flushing mechanism for making an existing cistern as into the dual flush cistern includes a lever positioned outside the cistern for operating the cistern. A hole is configured at bottom portion of the container. A valve is attached at a bottom of the stem to restrict the flow of water. The valve includes a bush attached thereto. A switch is operably attached on the lever. The switch includes a stopper configured at rear side of the switch for engaging or disengaging with the flushing stem thereby setting a full or reduced flush condition. The stopper engages with the flushing stem through a first slot configured on the lever of the existing cistern and a second slot configured on the existing cistern.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
FIG. 1 shows a dual flush cistern in accordance with an embodiment of the present invention;
FIG.2 shows the cistern of FIG. 1 in operating condition;
FIG. 3 shows a flush lever with a switch in full flush condition of the cistern of FIG. 1;
FIG. 4 shows an exploded view of the flushing assembly;
FIG. 5 shows a sectional view of cistern of FIG. 4 in full flush condition;
FIG. 6 shows the flush lever with the switch of FIG. 3 in reduced flush condition; and
FIG. 7 shows a sectional view of cistern of FIG. 3 in reduced flush condition.
DETAILED DESCRIPTION OF THE INVENTION
Although specific terms are used in the following description for sake of clarity, these terms are intended to refer only to particular structure of the invention selected for illustration in the drawings and are not intended to define or limit the scope of the invention.
References in the specification to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
In general aspect, the present invention relates to a dual flush cistern that includes a single stem with integrated float which can be lifted fully and partially by actuation of a mechanical switch and lever to get full flush and reduced flush respectively. The present invention also provides a flushing mechanism that can be adapted in the existing single flush cisterns to convert it into dual flush cistern.
Referring to FIGS. 1 and 2, a dual flush cistern (100) in accordance with an embodiment of the present invention is shown. The cistern (100) includes a fill valve (10) for filling water up-to a desired level in a cistern (100) and a flushing assembly (110). The flushing assembly (110) includes a lever (40) having a switch (30) operably attached on the lever (40). The lever (40) is positioned outside the cistern (20). This dual flush is operated by the switch (30) and the lever (40). The switch (30) includes a stopper (35) attached at rear side thereto. The stopper (35) engages with the flushing stem (50) through a first slot (36) configured on the lever (40) and a second slot (37) configured on the cistern (100). In an embodiment, the switch (30) is operable in a sliding or rotating configuration. Position of the switch (30) decides the full or reduced flush condition. The user presses the lever (40) for flushing once the switch (30) is set at a desired position.
The stopper (35) engages with the flushing stem (50) positioned inside the cistern (100) through a common actuating lever (25) which lifts the stem (50). The stem (50) includes a float (60) movably positioned surrounding the stem (50) such that an inner profile of the float (60) matches with the outer profiled of the stem (50). The stem (50) having the float (60) are positioned inside a container (70). The outer profile of the float (60) is in slidable contact with the inner profiled of the container (70). An annular space (72) is configured between diameter of stem (50) and diameter of hole in container (70). The bottom portion of the container (70) has a central hole (71) for passing the stem (50) and defining the annular space (72) between the stem (50) and the central hole (71). In an embodiment, the container (70) has a hole (65) of a predefined diameter configured at bottom portion thereof. Bottom portion of the container (70) opens to an outlet (75) that flushes water from the cistern into the toilet vessel. The outlet (75) is covered by a valve (85) attached at a bottom of the stem (50) to restrict the flow of water in default configuration. The valve (85) includes a bush (90) of a predefined height and diameter attached thereto. The bush (90) is attached on a top surface of the valve (85). In an embodiment, the bush is made up of rubber.
It is to be noted here that diameter of the bush (90) coincides with the diameter of the off-centered hole (65) to restrict the movement of the float (60). In full flush condition, the off-centered hole (65) gets sealed by the bush (90) and water is discharged from container through annular space (72) only. This causes the water level within the container (70) to push the valve (85) slowly thereby providing more time to the stem (50) to remain in raised condition. A buoyancy force acting on the float (60) determines the time for shutting off the flushing of water from the cistern. When water level within the container (70) comes down to a certain level, the stem (50) losses its buoyancy and fall down due to gravity and the outlet (75) gets sealed by the valve (85) to stop discharge to the vessel.
Referring to FIGS. 3 to 5, configuration of the cistern in case of full flush condition in accordance with the present invention is shown. The switch (30) is set in the position selected for full flush condition. The lever (40) is pressed downward to actuate the lever (40) connected with the stem (50) through actuating common lever (60) which lifts the stem (50) to upmost point. In this condition, the off-centered hole (65) configured on the valve (85) gets sealed by the rubber the bush (90). During full flush condition, the stem (50) remains in a raised position by the buoyancy of the float (60). It is understood here that the amount of water discharge from the cistern (20) container (70) to the toilet vessel can be regulated by regulating the time taken for the stem (50) to remain in raised position as outlet opening is kept constant. Time taken to discharge water from the container (70) is directly proportional to square root of head of water (height of water level within container) and inversely proportional to square value of diameter of the off-centered hole (65) for discharge of water and area of gap between diameter of stem (50) and diameter of hole in container (70) i.e area of annular space (72).
In accordance with the present invention, diameter of the off-cantered hole (65) plays important role in flushing water during reduced flush. Time required for water discharge from the vale (85) depends on the diameter of the off-centered hole (65) and head of water in the container (70). If the diameter of the off-centered hole (65) increases. Time taken by water to discharge through the container (70) decreases thereby decreasing the amount of water discharged through the cistern. If the diameter of the off-centered hole (65) decreases. The time taken by water to discharge from the container (70) increases resulting in discharging greater amount of water. The diameter of the off-centered hole (65) depends on amount of water to be flushed in reduced flushing condition compared to full flush condition. Diameter of the off-centered hole (65) approximately equals to 0.25 times diameter of the outlet (75) for reduced flushing. Diameter of the bush (90) is slightly greater than the diameter of the off-centered hole (65) to completely block the off-centered hole (65) during full flush operation. The height (95) by which stem (50) is lifted upwards in reduced flush is approximately 60 to 75 % value of height (95) of the stem (50) lifted upwards in full flush condition.
In accordance with an embodiment, in full flush operation, the lever (40) is pressed downwards to maximum down position which lifts stem (50) connected to the lever (40) to move upwards to maximum upward position. The switch (30) is placed on the lever (40) which can engage or disengage the stopper (35). For full flush, stopper (35) is disengaged making flush lever to move to max. down position. The flushing stem (50) after moving to predefined position, seals the bottom side of the off-centered hole (65) through the rubber bush (90). Sealing created by the rubber bush (90) delays flow rate of water draining from container (70) as area for water to flow is reduced. Water is discharged from the container (70) only through annular space (72). This makes stem to remain floated by buoyancy force created by water inside container (70) for extra time. This extra time allows water from cistern to be fully flushed.
Referring to FIGS. 6 and 7, configuration of the cistern in case of reduced flush condition in accordance with the present invention is shown. In this condition. the switch (30) is slide/rotated in a position to engage the stopper (35) at provision of a cistern body (100). As the lever (40) is pressed downward, the stem (50) and the actuating common lever (25) moves downward partially. In this condition, the off-centered hole (65) remains open as the bush (90) does not block it. Accordingly, the water level within the container (70) comes down faster. The water level within container (70) at which the stem (50) losses its buoyancy early due to the flow of the water from the annular space (72) and falls down due to gravity and seal the outlet (75) by the valve (85) to stop discharge to vessel to achieve reduced flush.
In reduced flush operation, the stopper (35) is engaged by the switch (30) placed on lever (40) with the flushing stem (50). Due to engagement of the stopper (35), after pressing, the lever (40) moves downwards partially instead of full down position which makes the stem (50) connected to the stopper (35) to move up partially. Due to partial movement of the stem (50), the off-centered hole (65) does not get blocked, which allows water from the container (70) to disperse freely from the annular space (72) between diameter of stem (50) and diameter of hole in container (70). Water level inside the container (70) comes down faster which reduces buoyancy force. Due to faster reduction of buoyancy force, the stem (50) moves downwards in less time thereby shutting off the flushing of water from cistern early.
In accordance with an embodiment, the flushing assembly (110) of the present invention can make an existing cistern similar to that of the cistern as disclosed in the present invention. The flushing assembly (110) includes a switch (30) operably attached on the lever (40) positioned on the existing cistern. The switch (30) includes a stopper (35) configured at rear side of the switch (30) for engaging or disengaging with the flushing stem (50) of the cistern. The position of the switch (30) decides a full or reduced flush condition. An off-centered hole (65) is configured at bottom portion of the container (70) other than the already present central hole (71). A bush (90) is positioned on the valve (85) attached at a bottom of a stem (50) such that the bush (90) can fit in the off-centred hole (65) in required condition. A buoyancy force acting on the float (60) determines the time for shutting off the flushing of water from the cistern. The container (70) having the central hole (71) for passing the stem (50) and defining an annular space (72) between the stem (50) and the central hole (71) in container (70) through which water from the container flushes. The bush (90) closes the off-centered hole (65) when the flushing stem is lifted full and maintains open when the flushing stem is lifted partial for changing buoyancy force acting on the float (60) thereby setting a full or reduced flush condition. The stopper (35) engages with the flushing stem (50) through a first slot (36) configured on the lever (40) of the existing cistern and a second slot (37) configured on the existing cistern (100).
In accordance with the present invention, the dual flushing mechanism is operated only by single float, one lever and one flush valve. The design of dual flushing mechanism which has less cost than conventional dual flushing mechanism. The flushing mechanism of the present invention is easy to operate and reliable.
For example, in accordance with an embodiment, in case of full flush, time required to discharge water from container (70) was kept at 3.5 sec by selecting height of water head inside the container (70) and the annular space (72) between diameter of stem (50) and diameter of hole in container (70). It is to be noted that this time can be varied by changing height of water head inside container and diameter of hole in container. Amount of water flushed from tank (20) outlet (75) for 3.5 sec, depends on cistern dimension and opening area of bottom outlet (75). After 3.5 sec stem (50) moved downwards to seal outlet of tank (75) and flushing was stopped. The cistern was designed so that amount of water flushed was 6 litres in 3.5 sec.
In case of reduced flush, time required to discharge water from container (70) was kept 1.7 sec. The water discharged faster compared to full flush condition from container. The off-centered hole (65) was kept exposed while in full flush condition it was sealed by the rubber bush (90), but during reduced flush condition it was not sealed as stem (50) was not lifted upward completely. The off-centered Hole diameter (65) was such that it takes 1.7 sec to drain water from container to desired water level. Due to less available time, the amount of water flushed through tank was only 3 litres.
It is to be noted here that reduced flush was not limited to flush reduced amount of water than full flush. Amount of water flush during reduced flush was varied by changing off-cantered hole diameter (65). When the hole diameter was increased, the amount of water flushed from tank was less than 3 litres and when diameter was decreased, the amount of water flush was greater than 3 litres. The cistern design was also modified to observe the change during full flush condition from 6 litres to any amount of water flush (eg. 4 litres, 7 litres, 8 litres, 10 litres), it was observed that reduced flush volume was proportionally reduced or increased as per full flush condition. Ratio of diameter of the off-cantered hole (65) and that of diameter of outlet (75) can be varied by changing tank dimension and volume of tank
The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.
, Claims:
1. A flushing assembly (110) for a dual flush cistern (100), the flushing assembly (110) comprising:
a lever (40) positioned outside the cistern (100) for operating the cistern (100);
a flushing stem (50) connected to the lever (40) positioned inside the cistern (100) through a common actuating lever (25) for lifting the stem (50) with a float (60), a buoyancy force acting on the float (60) determines the time for shutting off the flushing of water from the cistern;
a switch (30) operably attached on the lever (40), the switch (30) includes a stopper (35) configured at rear side of the switch (30) for engaging or disengaging with the flushing stem (50) to define full flushing and reduced flushing conditions of the cistern by allowing a total lifting or a partial lifting of the flushing stem;
a container (70) having a central hole (71) for passing the stem (50) and defining an annular space (72) between the stem (50) and the central hole (71) in container (70) through which water from the container flushes;
an off-centered hole (65) configured at bottom portion of the container (70) for additional flushing of water from the container (70);
a valve (85) attached at a bottom of the stem (50) to restrict the flow of water through an outlet (75) of the cistern (100); and
a bush (90) attached on a surface of the valve (85), the bush (90) closes the of-centered hole (65) when the flushing stem is lifted full and maintains open when the flushing stem is lifted partial for changing buoyancy force acting on the float (60) thereby setting a full or reduced flush condition.

2. The flushing assembly (110) as claimed in claim 1, wherein the stopper (35) engages with the flushing stem (50) through a first slot (36) configured on the lever (40) and a second slot (37) configured on the cistern (100).

3. The flushing assembly (110) as claimed in claim 1, wherein an inner profile of the float (60) matches with the outer profiled of the stem (50).

4. The flushing assembly (110) as claimed in claim 1, wherein outer profile of the float (60) is in slidable contact with the inner profiled of the container (70).

5. The flushing assembly (110) as claimed in claim 1, wherein diameter of the bush (90) coincides with the diameter of the hole (65) to restrict the movement of the float (60).

6. The flushing assembly (110) as claimed in claim 1, wherein diameter of the off-centered hole (65) depends on amount of water to be flushed in reduced flushing condition compared to full flush condition.

7. The flushing assembly (110) as claimed in claim 6, wherein diameter of the off-centered hole (65) equals to 0.25 times diameter of the outlet (75) for reduced flushing.

8. The flushing assembly (110) as claimed in claims 1-7, wherein the height (95) by which stem (50) is lifted upwards in reduced flush is approximately 60 to 75 % value of height (95) in full flush condition.

9. The flushing assembly (110) as claimed in claims 1-8, wherein the cistern (100) is operated by single flush valve (85) and single lever (40).

10. A dual flush cistern (100) comprising:
a fill valve (10) for filling water up-to a desired level in a cistern (100); and
a flushing assembly (110) comprising:
a lever (40) positioned outside the cistern (100) for operating the cistern (100);
a flushing stem (50) connected to the lever (40) positioned inside the cistern (100) through a common actuating lever (25) for lifting the stem (50) with a float (60), a buoyancy force acting on the float (60) determines the time for shutting off the flushing of water from the cistern;
a switch (30) operably attached on the lever (40), the switch (30) includes a stopper (35) configured at rear side of the switch (30) for engaging or disengaging with the flushing stem (50) to define full flushing and reduced flushing conditions of the cistern by allowing a total lifting or a partial lifting of the flushing stem;
a container (70) having a central hole (71) for passing the stem (50) and defining an annular space (72) between the stem (50) and the central hole (71) in container (70) through which water from the container flushes;
an off-centered hole (65) configured at bottom portion of the container (70) for additional flushing of water from the container;
a valve (85) attached at a bottom of the stem (50) to restrict the flow of water through an outlet (75) of the cistern (100); and
a bush (90) attached on a surface of the valve (85), the bush (90) closes the off-centered hole (65) when the flushing stem is lifted full and maintains open when the flushing stem is lifted partial for changing buoyancy force acting on the float (60) thereby setting a full or reduced flush condition.

11. A flushing assembly (110) for converting an existing single flush cistern into dual flush cistern, the flushing assembly (110) comprising:
a switch (30) operably attached on the lever (40), the switch (30) includes a stopper (35) configured at rear side of the switch (30) for engaging or disengaging with the flushing stem (50) to define full flushing and reduced flushing conditions of the cistern by allowing a total lifting or a partial lifting of the flushing stem;
an off-centered hole (65) configured at bottom portion of the container (70) of the existing cistern; and
a bush (90) attached on a surface of the valve (85), the bush (90) closes the off-centered hole (65) when the flushing stem is lifted full and maintains open when the flushing stem is lifted partial for changing buoyancy force acting on the float (60) thereby setting a full or reduced flush condition.

12. The flushing assembly as claimed in claim 11, wherein the stopper (35) engages with the flushing stem (50) through a first slot (36) configured on the lever (40) of the existing cistern and a second slot (37) configured on the existing cistern (100).