FLUSHING MECHANISM FOR A DUAL FLUSH CISTERN

Abstract: A flushing mechanism for a dual flush cistern system comprises a float assembly (1) comprising a hollow valve stemn (2) carrying a sealing valve (3) for sealing the outlet opening of the cistern at or towards one end and being open at each end to define an overflow passage and a float (6) fixedly attached around the valve stem (2), a cylindrical guide member (7) surrounding the float (6) and having at the end adjacent the sealing valve at least one opening to allow liquid to pass to the outlet opening, an operating rod (17) arranged to move vertically upward to raise the float assembly (1) to open the vavle (3), first and second operating means (25, 26) arranged to effect such vertical movement of the operating rod (17), the first operating means (25), on operation, being arranged to raise the float assembly (1) a first distance to a level which the float assembly (1) is buoyant, and the second operating means (26) being arranged to raise the float assembly (1) a second distance, less than the first distance to a level at which the float assembly (1) is not buoyant, whereby when the first operating means (25) is operated and released, a first predetermined quantity of liquid flows from the cistern, and when the second operating means (26) is operated and released a second, smaller, predetermined quantity of liquid flows from the cistern.

Description: FLUSHING MECHANISM FOR A DUAL FLUSH CiSTERN This invention relates to a flushing mecnaπism for a dual flush cistern BACKGROUND TO THE INVENTION In recent years it has in many countries been a requirement that all new toilet cisterns installed snculd nave a dual-flusπ function in which a πjil flush releasing a large αuaπtity of flushing liquid can De used wnen solid waste is to disooseα of and a oartial flusn releasing a smaller quantity of fiusniπg liquid can De used when a full fiusn is not required for exarriDle wnen liquid waste is to oe αisooseα Many such mecπaπis s for dual flush cisterns nave oeen oroooseα In certain systems the cistern -s divided into two parts by a weir having a movable gate such that when a Dartial flush is required the gate remains closed and only the iiαuid on one side of the weir is released through the cistern outlet out wnen a full flusn is required the gate is opened allowing liquid en ooth sides of the weir to pass through the outlet. Examples of such dual flush mechanisms are disclosed in AU-B-56165/30 and WO93/1528^ Another type of dual flushing mechanism relies on closing the outlet valve after different times deoendiπg on wnether a full or oart.al flush is required Examples of such mechanism are described for example in AU-A-28538/84, AU- B-801 1 1 /87 AU-B-40336/85 and WO93/15284 The prior art mechanisms generally include a float assembly comprising a float associated with the valve stem of the outlet closure valve and either attacned to or slideable on the valve stem The float reαuces the negative buoyancy of the float assembly so that the float assembly sinks at a slower rate to close the valve than it would do if the float were not present The majority of the prior an mechanisms include a large number of moving Darts and are complicated in their structure in that various non-linear motions are involved in operation of the valve It is the ODject of this invention to Drovide a flusning mecnamsm for a dual flush cistern that is very much simpler than the existing mechanisms SUMMARY OF THE INVENTION This invention provides a dual flush system comprising a float assembly comprising a hollow valve stem carrying a sealing valve for sealing the outlet opening of the cistern at or towards one end and being open at eacn end to define an overflow passage and a float fixedly attached around the valve stem a cylindrical guide member surrounding the float and naviπg at the end adjacent the sealing valve at least one opening to allow liquid to pass to the outlet opening, an operating rod arranged to move vertically upward to raise the float assembly to open the valve, first and second operating means arranged to effect such vertical movement of the operating rod, the first operating means, on operation being arranged to raise the float assembly a first distance, and the second operating means being arranged to raise the float assembly a second distance less than the first distance whereby wnen the first oDerating means is ooeratec and released a first predetermined quantity of liquid flows from tne cistern and when the second operating means is operated and released a second smaller predetermined quantity of liquid flows from the cistern The float preferably comprises an inverted cup-shaoed merriDer wnich traps air, therepy reducing the negative buoyancy of tne float assembly The rate of closing of the valve is dependent on the hydrostatic pressure acting on the float and on the distance that the float has to move to close the valve Thus the float assembly is designed so that when the float assemoly is raised oy the first full flushing, distance the float is buoyant and so falls to close the vaive as the level of the liquid supporting it drops thereby allowing the oredetermined Quantity of liquid to flow from the cistern However when it is raised oy the second, partial flushing, distance the hydrostatic pressure on the float surface is sucn that the float is not Ducyaπt and the valve starts to close as soon as the operating means is released the rate of closure oeiπg such that the second predetermined amount of liquid flows from the cistern In some instances for examole wnen the operating means is held down for too long a time or is operated too violently the water level in the cistern may drop so far or the float assembly may gain sufficient momentum to move further uDward than the second oredetermined distance that tne assembly may oecome buoyant Preferably therefore, the second operating means on operation in addition to raising the float assembly also operates a stop mechanism acting on some part of the float assembly to prevent movement of the float assemσly greater than the second distance In its simplest form, such stop mechanism comprises a rod which, on operation of the second operating means, is introduced into the float guide member to a predetermined level to contact the upper surface of the float when the float nas reached the desired height Preferably the stop mechanism is adjustable to allow fine-tuning of the quantity of liquid that flows from tne cistern in a partial flusn This may be achieved by meεns of a screw tnread on the rod oy means of vvnich the lower end of the rod can oe raised or lowered relative to the float The rod preferably passes througn a c uide merriDer mounted on the πm of the float guide member in order to constrair movement of tne rod only <o an up and down movement The operating means preferably comprises a pair oi push buttons on the top of the tank, depression of which moves a pivoted iever which is connected to the operating rod. However, especially when the mechanism is intended for use as a conversion kit for an existing lever operated cistern the ooeratiπg means may comprise a pair of levers, for example mounted on concentric shafts with appropπate linkages to the operating rod. The ODerating mecnanism is preferably carried on a oracket wnicn is mounted on the side of tne float guide means, the length of wnich is oreferaDiy adjustable to allow the mecnanism to be used in cisterns of different neight In a mechanism in which the length of the bracket is adjustaDie tne length of the coerating roc and of the stop rod. 'when present must also be adiustaois in a preferred form of the operating mechanism, tne connection oetween tne operating means and the float assembly, comoπses a rod or oar with a plurality of spaced holes at least at its end adjacent to the loat assemoly wnicn cooperates with a bracket on the float guide memoer whicπ aiso nas at least one hole through which a fixing pin can be passed into one of the noles on the oracket. The operating rod and the stop rod may be telescooic and mayoe held together by locating pins which can pass through locating hoies. as necessary. In the case of the step rod, the rod is preferably mounted in a U-snaped rod carrier and the locating pins are permanently attached to the rod so that the rod can be rotated to snap the pin into and cut of one of a plurality of notches on the rod carrier. The rod carrier may be mounted by a screw thread on the second operating means to allow fine adjustment of the effective iength of tne rod. DESCRIPTION OF PREFERRED EMBODI ENT The invention will now be described in greater oetai! by way of xamoie with reference to the drawings, in which: - Fig 1 is an isometric view of one form of flusning mechanism according to the invention in the closed Dosition of the valve Fig 2 is an isometric view of the valve mechanism of fig 1 in the full flush position Fig 3 is an isometric view of tne mecnanism of fig 1 in the oartiai flush position Fig 4 is a section through the mecnanism of fig 1 in tne full flush oosmon but with tne stoo rod not shown, and Fig 5 is a view as in fig 4 but in the paraal flusn ocsition As shown in the crawiπgs the flusning mecnanism comorises a rioat assemDly C indicated generally by r eference numeral 1 wnicn comorises a vaive stem 2 wnicn 'S nollow and ooen at Doth ends and carries τ owarcs one eno a vaive closure member 3 wnicn seats on a valve seat 4 on a fixture me oer 5 ov wnicn the float assemDly 1 is mounted to the outlet 1 (not snown) of a toilet system ' also not shown) Float assemDly 1 also includes a float 6 .n the form of an .πvertec cup ^3 member whicn is fixedly attached around valve stem 2 Float 6 is closely surrounded by a cylindrical oortion 7 of a float guide 8 Cylindrical Dortion 7 is soaced from the bottom of the cistern and the valve seat by means of iegs 9 on a spacer member 10 wnich is attacned to cylindrical portion 7 by a oayonet fixing 1 1 at one end and at the other end is attached to fixture memoer 5 The base of 20 cylindrical portion 7 is closed to limit the maximum movement of float assemDly 1 On its outer surface cylindrical portion 7 carries a σracket 12 for mounting a sucport arm 13 for the flush operating mecnanism The suoport arm 13 is cranked at its upper end 14 and terminates in a yoke 15 supporting a oivotaliy mounted operating lever 16 One end of lever 16 is attached to a cranked ODerating rod 17 25 which extends into cylindrical portion 7 the portion within cylindrical ootion 7 being attacned to valve stem 2 oy means of a collar 18 which abuts against the underside of a flange 19 on valve stem 2 Collar 18 is attached to ODerating red 15 by means of a pin 20 wnich passes into one of a numDer of noies 2ι Ή operating rod 17 Downward pressure on the end of lever 15 remote from the connection oi operating rod 17 causes operating rod 17 to move upwardly carrying the float assembly 1 with it and thereby causing the valve 3, 4 to open to allow liquid to exit the cistern Support arm 13 is connected to bracket 12 oy means of locking pins (not shown) engaging in one or more of holes 22 in supporting arm 13 so that the distance between the ODerating mechanism and the float assembly 1 can be varied to suit cisterns of different heignt Operating rod 17 is formed in two parts connected by means of pins 23 locating in holes 24 in the two Darts of the operating rod 1 7 thereby allowing length adjustment of operating rod 17 The ooeratmg mechanism includes two Dush outtons 25 26 wnich serve to depress the eno of lever 16 remote from the connection of ODerating rod 1 7 The Dush outtoπs 25 25 are spring loaded so that they are biased to an inoperative oositioπ Each of pusn buttons 25, 26 has a projection 27 28 on its lower surface wnicn when a button 25 26 is pressed acts on lever 16 to move operating rod 17 upwardly Projection 27 on the full flush button 26 is longer than tne projection 28 on partial flush button 26, so that when push button 25 is pressed, the ODerating rod 17 is lifted by a greater distance and hence lifts the float assembly further away from tne valve seat 6 then when push button 26 is pressed The projection 28 on push button 26 is connected to a further lever 29 wnich at one end 30 overlaps the operative end of lever 16 and at the other end 31 is attached to a stop rod 32 via a U-shaped rod carrier 33 Stoo rod 32 oasses through a guide 34 on the rim of cylindrical portion 7 Depression of button 26 causes projection 28 in addition to causing operating rod 16 to move uowardly thereby raising the float assembly 1 also depresses stop rod 33 within cylindrical portion 7 to further limit the pcsεibie movement of float assemDly 1 Rod carrier 31 is attached to lever 29 by means of a screw 34 wnich passes through a screw-threaded bore in end 31 of lever 29 to allow adjustment of the distance between rod carrier 33 and lever 29 thereby allowing fine tuning of the distance that rod 32 extends into cylindπcal portion 7 In addition carrier member 33 has a plurality of notches 35 into which a pin 36 protruding from the surface of rod 32 can be snapped to allow larger adjustment of the effective teπgtn of rod 31 As shown in fig 4 in the full flush position float assemDly 1 is r aιsed oy means of ooerating red 17 to a level sucn that the too of float 6 aimcs: reacπes the upper edge of cylindrical portion 7 At this level tne air trapped under rioat 5 .s sufficient to make float assembly 1 buoyant so that the float assemoiy 1 ooes not sink under its own weignt wnen push button 25 is released but instead merely falls ss the water level in the cistern drops As snown in Fig 5 in the partial flush portion float assemolv 1 'S raised to a lesser level At this lower level the hydrostatic pressure acting en float 6 is sufficient to overcome the buoyancy of float assembly 1 so that wnen push outton 26 is released, the float assembly 1 will sink under its own weight albeit at a slower rate than it would if the float 6 were not present

Claims: CLAIMS A flusning mechanism for a dual flush cistern system comprising a float assembly ( 1 ) comprising a hollow vaive stem (2) carrying a sealing valve (3) for sealing the outlet opening of the cistern at or towarαs one end ana being open at eacn end to define an overflow passage and a float (5) fixedly attached around the valve stem (2), a cylindrical guide member (7) surrounding the float (5) and having at the end adjacent the sealing valve at least one opening to allow liquid to pass to the outlet opening, an operating rod (1 7) arranged to move vertically upward to raise tne float assemDly ( 1 ) to open the vaive (3). first and second ooerating means (25 26) arranged to effect such vertical movement of the operating roα ι l . the first operating means (251 on operation being arranged to raise the float assembly ( ", ) a first distance to a level which the float assembly ( 1 > ,s buoyant aπc tne second operating means (26) being arranged to raise the float assemoiy ( 1 ) a secoπc distance less than tne first distance to a level at wnich tne float assembly (1 ) is not buoyant, wnereby wnen the first operating means (25) is " ' operated and released a first predetermined quantity of liquid flows from the cistern and wnen the second operating means (25) is operated and released a second, smaller predetermined quantity of liquid flows from the cistern 2. A mechanism according to claim 1 , wherein the float (6) comprises an inverted cup-shaped member which traps air thereby reducing the negative buoyancy of the float assembly (1 ) 3 A mecnanism according to claim 1 or claim 2 wherein the second ooerating means (25) on operation in addition to raising the float assembly (1 ) also operates a stop mechanism (32, 33) acting on some part of the float assembly (1 ) to prevent movement of the float assembly (1 ) greater than the second distance A mechanism according to claim 3, wherein the stop mecnanism (32 33) comprises a rod (32) which on operation of the second operating means (26) is introduced into tne float guide merriDer (7) to a predetermined level to contact the upper surface of the float (6) when the float (6) has reacned the desired height A mechanism according to claim 4 wherein the stop mechanism (32 33 ) is adjustable to allow fine-tuning of the quantity of liquid tnat flows trom the cistern in a oartial flush A mecnanism according to claim 4 or claim 5 wherein tne rod (32 1 passes through a guide member (34) mounted on the πm of the float guide member (7) to constrain movement of the rod (32) only to an up and down movement - A mechanism according to anyone of claims 1 to 5 wherein tne ooerating means (25 26) comprises a pair of push buttons on the top of the cistern depression of which moves a pivoted lever (16) which is connected to the operating rod (17) A mechanism according to anyone of claims 1 to 7, wherein the ooerating mechanism is carried on a bracket (1 3) which is mounted on the side of the float guide means (7), the length of the bracket 13 being adjustable to allow the mechanism to be used in cisterns of different height the length of tne operating rod ( 17) and of the stop rod (32 33) wnen present oeing also adjustable

Inventors: HO KING CHEE, HO, KING CHEE
Applicants: CISTERN TECHNOLOGY PTE LTD, HO KING CHEE, CISTERN TECHNOLOGY PTE. LTD., HO, KING CHEE
Application year: 2001
Main classification: E03D3
IPC codes: E03D1