TOILET CISTERN DUAL FLUSH VALVE

Abstract: The invention provides a toilet cistern dual flush valve (10) operable selectively in a full flush mode in which a relatively large volume of water is discharged from the cistern or a partial flush mode in which a relatively small volume of water is discharged from the cistern. The dual flush valve (10) comprises a stem (36) carrying a valve closure (38) seatable on an outlet from the cistern, means to raise the stem (70, 72,74), buoyant means (50) attached to the stem (36) which in the full flush mode maintains the stem (36) in the open position until the relatively large volume of water has been discharged and the buoyant means (50) loses buoyancy whereafter the stem (36) descends under gravity to the closed position, and means (54) which operates in the partial flush mode to add sufficient mass to the stem when the relatively small volume of water has been discharged causing the stem (36) to descend to the closed position.

Description: 'TOILET CISTERN DUAL FLUSH VALVE" BACKGROUND TO THE INVENTION THIS invention relates to a toilet cistern dual flush valve which is capable of discharging different volumes of water from the cistern at the election of the operator. Toilet cisterns generally have a fixed volume of water, the full content of which is discharged to the toilet bowl when flushing is initiated. 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 minimised resulting in reduced water consumption and associated costs to the consumer. A number of dual flush toilet cistern valves have been devised with a view to providing the user of the toilet with a choice between a full flush, in which the full content of the cistern is discharged into the toilet 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. Another problem with some known dual flush valves is their use of two separate floats each at the end of a relatively long, transverse float arm to achieve selective locking of a valve stem carrying the valve closure which controls the discharge of water from the cistern to the bowl. The long float arms make such valves unsuitable for use in the compact cisterns which are currently in favour. The present invention seeks to provide a compact, simple and relatively inexpensive dual flush valve. SUMMARY OF THE INVENTION According to the invention there is provided a toilet cistern dual flush valve operable selectively in a full flush mode in which a relatively large volume of water is discharged from the cistern or a partial flush mode in which a relatively small volume of water is discharged from the cistern, the valve comprising: a valve stem carrying a valve closure seatable on an outlet from the cistern and movable between a raised, open position in which the closure is spaced from the outlet and a lowered, closed position in which the closure seats on the outlet, means operable in both full and partial flush modes to raise the stem, operatively buoyant means attached to the stem which in the full flush mode maintains the stem in the open position until the relatively large volume of water has been discharged and the buoyant means loses buoyancy whereafter the stem descends under gravity to the closed position, and means which operates in the partial flush mode to add sufficient further mass to the stem when the relatively small volume of water has been discharged, to cause the stem to descend to the closed position. A preferred embodiment of the invention includes actuators which are selectively, manually operable to initiate the full or partial flush mode, an upper float unit, upper and lower collars on the stem, and linkages extending between the actuators and the upper float unit such that operation of either actuator raises the upper float unit into abutment with an upper collar on the stem thereby raising the stem to the open position. The linkages may include a toggle attached pivotally to the upper float unit and carrying a detent, the arrangement being such that operation of the relevant actuator to initiate a partial flush causes the toggle to pivot to a position in which the detent engages the lower collar and adds the mass of the upper float unit to the stem when the water in the cistern has dropped to a level at which the upper float unit loses buoyancy. The upper float unit may include a water reservoir to accommodate a volume of water providing gravitational mass. Both the main float and the upper float unit may include inverted cup- shapes to accommodate air which renders both the main float and upper float units buoyant in water. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a partially exploded perspective view of a dual flush valve according to this invention; Figure 2 shows a side view of the stem, main float and closure assembly of the dual flush valve of Figure 1 ; Figure 3 shows a side view of the secondary float unit of the dual flush valve of Figure 1 ; Figure 4 shows a side view of relevant components of the dual flush valve of Figure 1 when a full flush is initiated; Figure 5 shows a vertical cross-sectional view of relevant components of the dual flush valve of Figure 1 when a partial flush is initiated; Figure 6 shows a horizontal cross-section at the line 6-6 in Figure 4; Figure 7 shows a horizontal cross-section at the line 7-7 in Figure 5; Figure 8 shows a side view of a second embodiment of the dual flush valve according to the invention; Figure 9 shows an exploded perspective view of components for suspending the dual flush valve of Figure 8 in a cistern; and Figure 10 shows a perspective view of actuating buttons of the dual flush valve of Figure 8. DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 shows a dual flush valve 10 according to this invention. The valve 10 includes an outlet structure 12 having a threaded spigot 14, a nut 16 mateable with the spigot, a flange 18 and three legs 20 extending vertically from the flange and carrying enlargements 22 at their upper ends. The valve 10 also includes a housing 24 of generally inverted cup shape. The housing has a cylindrical skirt 25 carrying circumferentially spaced locking formations 26 and an annular upper wall 28 from which a cylindrical sleeve 30 projects vertically. When installed in a toilet cistern 31 the spigot 14 is passed downwardly through an opening in the base 33 of the cistern and the outlet structure 12 is locked in place by engaging the nut 16 with the spigot beneath the base. The housing 24 is then located over the outlet structure 12 with the enlargements 22 received through enlarged zones 32 of the locking formations 26. The housing is then rotated relative to the outlet structure to locate the enlargements 22 over relatively narrow zones 34 of the locking, formations 26. \t will accordingly be understood that the housing 24 is locked to the outlet structure 2 by what is, in effect, a bayonet action. The dual flush valve 10 also includes a vertical, hollow stem 36 carrying a closure 38 at its lower end which can seat on the rim of the outlet opening 40 through the outlet structure 12. The stem passes slidably through the sleeve 30 of the housing 24 and carries a relatively large collar 42 and a relatively small collar 44 at spaced apart positions near to its open upper end. Beneath the upper wall 28 of the housing the stem passes through, and is fixed to, a central sleeve 46 extending downwardly from the horizontal upper wall 48 of a main float 50. The float 50 is in the form of an inverted cup and has a cylindrical skirt 52 depending downwardly from the periphery of the upper wall 48. The outside diameter of the float skirt 52 is somewhat less than the inside diameter of the housing skirt 25 so the float 50, which is fixed to the stem 36, is capable of free vertical movement within the housing. Another component of the valve 10 is a secondary or upper float unit 54 which has an upper cup-shaped reservoir section 56, a lower float section 58 of inverted cup-shape and a horizontal wall 60 serving both as a base of the section 56 and an upper wall of the section 58. A central, vertical sleeve 62 extends upwardly from the wall 60. The stem 36 extends freely through this sleeve which has an internal diameter greater than the external diameter of the lower collar 44 but smaller than the external diameter of the upper collar 42. The upper edge of the sleeve 62 is formed with a cut-out 64 shaped as shown in Figure 3. Pivoted externally to the side of the sleeve 62, at a pivot axis 66 located generally beneath the cut-out 64, is a toggle 68 having the shape of a sector of a circle. The upper edge of the toggle carries a detent 70 which projects transversely into the cut-out 64 in a direction towards the stem 36. Attached pivotally to the toggle at spaced apart points on opposite sides of the pivot axis 66 are upright arms 72 and 74. At their upper ends, the arms 72 and 74 are pivoted to respective transverse arms 76 and 78. The arm 76, which is a full flush arm, extends from a collar 80 fixed on a hollow shaft (not shown) which in use extends through the front wall 81 of the cistern and to which a full flush actuating handle 82 is connected. The arm 78, which is a partial flush arm, extends from a collar 84 fixed on a shaft 85 which extends rotatably through the hollow shaft and to which a partial flush actuating handle 86 is connected. An element 88 extends from the collar 84 and overlies the collar 80. When the valve 10 is installed in the cistern in use, the actuating handles 82 and 86 are located externally on the front wall 81 of the cistern for selective operation by the user. When the full flush actuating handle 82 is depressed, i.e. pivoted in a clockwise direction as illustrated, the hollow shaft to which it is attached will rotate in a clockwise direction, thereby raising the arm 72 via the collar 80 and full flush arm 76. Because of the presence of the element 88, this action also rotates the collar 84 and hence the shaft 85 to which the partial flush actuating handle 86 is connected. As a consequence, the arm 74 is also raised via the partial flush arm 78. The arms 72 and 74 apply balanced lifting forces to opposite sides of the toggle 68 which is itself lifted but does not rotate. When the partial flush actuating handle 86 is depressed, the shaft to which it is connected rotates accordingly. The arm 74 is therefore raised via the collar 84 and partial flush arm 78. However in this case, there is no corresponding movement of the arm 72. The arm 74 applies an unbalanced force to the toggle and causes it to pivot, in an anticlockwise direction as viewed in Figure 1 , on the axis 66. The detent 70 moves to a position in which it extends directly towards the axis of the stem 36. The operation of the dual flush valve 10 will now be explained with reference to a full flush action and a partial flush action. In both instances a flushing action will commence when the cistern is full of water, volumes of air are trapped in the main float 50 and in the float section 58 of the upper float unit 54, the reservoir section 56 of the upper float unit is full of water, and the valve closure 38 is seated in sealing manner on the rim of the outlet opening 40. Full Flush As just explained, a full flush is initiated by depressing and then releasing the actuating handle 82. Depression of the actuating handle has the effect of raising both arms 72 and 74. Because the toggle 68 is attached to the upper float unit 54 at the pivot axis 66, the upper float unit is pulled upwardly. When the upper edge of the sleeve 62 encounters the upper collar 42 on the stem 36, the stem is also raised. This lifts the valve closure 38 off the rim of the outlet 40, allowing water to discharge from the cistern through the spigot 14 and into the toilet bowl to perform a flushing action. During flushing the stem is kept in a raised position by the buoyancy of the main float 50, attributable to the pocket of air trapped therein. Flushing will continue until the water level in the cistern has dropped to a level where the float 50 loses buoyancy, allowing the stem 36 and with it the closure 38 to drop. The closure reseats on the rim of the outlet opening 40, thereby closing the valve again. The upper float unit 54 is kept in a raised position during an initial part of the full flush by the air pocket trapped in the lower float section 58. When the water level in the cistern drops beneath the lower edge of the float section 58, the float unit 54 will descend with the water level until it eventually comes to rest on the upper wall 28 of the housing 24. As described previously, the stem 36 and closure 38 are kept in the raised position by the buoyancy of the main float 50 until the full flush is completed It is to be noted that because the toggle does not pivot when the full flush is initiated, the detent 70 remains in a position off-set laterally from the axis of the stem 36, and so does not interfere with the collar 44, as shown in Figure 6. Partial Flush The partial flush is initiated by depressing the actuating handle 86. As described previously, this has the effect of raising the arm 74 only. The unbalanced force on one side of the toggle causes the toggle to pivot as it is pulled upwardly by the arm 74. As in the full flush mode of operation, the upper edge of the upper float unit 54 encounters the upper collar 42 and raises the stem 36 and closure 38, initiating the flush. However in this case, the pivotal movement of the toggle aligns the detent 74 with the axis of the stem, with the result that the detent locates over the collar 44, as shown in Figure 7. As in the full flush mode the stem 36 is kept raised and the closure 38 remains in an open position because of the buoyancy of the main float 50. The upper float unit is also kept raised by the buoyancy attributable to the air pocket trapped in the float section 58. When a partial flush has taken place, the water in the cistern has dropped to the level of the lower edge of the float section 58. At this point, the float unit 54 loses buoyancy and starts dropping. Because the detent 70 has located over and moves into contact with the collar 44, the gravitational force on the float unit 54 is transferred to the stem 36. While the unit 54 is itself relatively light, its mass is considerably increased by the volume of water in the reservoir section 56. The combined mass of the float unit 54 and the volume of water in the reservoir section is sufficient to overcome the buoyancy of the main float 50, so the stem is forced downwardly for the closure 38 to reseat on the rim of the opening 40 and close the valve. At this stage, only a part of the cistern contents have been discharged. As the float unit 54 drops the toggle 68 is reset to a neutral or balanced position, in which the detent is free of the collar 44, by the upward force on the toggle applied by the arm 72. In both the full and partial modes of operation, the cistern is refilled in the normal way via a cistern inlet valve which forms no part of the present invention and which is not shown in the drawings. The design of the valve 10 described above is suitable for use in modern, compact toilet cisterns in which internal space is at a premium. It will also be appreciated that the valve 10 is of sufficiently simple construction to enable it to be manufactured at relatively modest cost. A feature of the design is the use of the mass of water in the reservoir section 56 to apply a valve closing force in the partial flush mode. It is however within the scope of the invention for the required mass to be provided by, for instance, a weight attached to the float unit, although this would increase the overall cost of the valve. A second embodiment of a dual flush valve is depicted in Figure 8 and indicated by the reference numeral 1 10. In this instance actuating buttons 112 and 114 replace the pivoted actuating handles 82 and 86 on the front wall of the cistern as described in the first embodiment. The actuating buttons 112 and 114 are clearly illustrated in Figure 10. It will be noted that they have flat portions at their sides allowing them to be placed juxtaposed within the flat portions facing one another. Figure 8 shows that the actuating buttons 1 12 and 114 are located in a sleeve 118 and are moveable relative to each other in the sleeve 118. It will be noted that the sleeve is a carried by a support beam 120. The support beam 120 is suspended within the cistern by two brackets 122 and 124. The connection between the support beam 120 and the brackets 122 and 124 is illustrated in Figure 9. The support beam 120 has a tongue 126 locatable in a cavity 128 of the bracket 122. Once the tongue 126 is located in the cavity 128, it can be secured with a bolt 134, shown in Figure 8, that is placed through holes 130 and 132 which are located in the tongue 126 and the bracket 122 respectively. The support beam 120 is connected to the support bracket 124 in a similar manner. Various different options are available for suspending the brackets in position. Figure 9 illustrates one possibility in which the bracket 122 has two protruding members 136. and 138 at its ends. The protruding member 136 is slidably locatable in a slot 140 defined by a support frame 142 that is attached to the inside of the front wall (not illustrated) of the cistern with adhesive. The protruding member 138 is attached to the back wall of the cistern in a similar fashion. Placing the cistern's lid in position will prevent the protruding members being removed from their respective slots. It is envisaged that slots similar to the slot 140 can be formed in the walls of the cistern itself. However, the dual flush valve 110 should also be capable of use in existing cisterns and in such situations will require the use of frames as described above. Turning again to Figure 8, it will be noted that the sleeve 118 has two lugs 144 and 146 connected thereto, each support frame having a pivot pin indicated by the reference numerals 148 and 150 respectively. The pivot pin 148 pivotally connects the button 112 via an arm 151 with an arm 152, which is in turn connected to an arm 156. A portion of the arm 151 is located in a cavity 153 shown in Figure 10. In operation the linear movement of the button 112 in a downward direction will cause the arm 152 to pivot on the pivot pin 148 thereby moving the arm 156 in an upward direction. This movement, illustrated in broken lines in Figure 8, will initiate a partial flush as described previously. Depressing both buttons simultaneously will lead to a full flush, also as described previously. A further feature of the second embodiment is also illustrated in Figure 8. It is know that toilet cisterns are normally manufactured in two standard sizes, i.e. 6 I and 9 I. In different embodiments of these cisterns the height of the cistern may vary. From an economic perspective it would therefore be desirable if a single dual flush valve 110 could be installed and used in cisterns having either of these standard sizes and varying cistern heights. This objective is addressed by having arms 156 and 158 of telescopic construction. Telescopic movement is achieved in that the arms 156 and 158 include ratchets 160 and 162 as well as catches 164 and 166 respectively. Telescopic construction is well known in the art and it will suffice to say that each catch can be moved on the associated ratchet in such a manner that the effective length of the arms 156 and 158 can be either increased or decreased depending on the cistern size. In Figure 8 both the lower float section 58 of the upper float unit 54 and the float 50 are filled with closed cell foam. It has been mentioned that the floats 50 and 54 are kept in a raised position due to the buoyancy attributable to air pockets trapped therein. Using closed cell foam manufactured air pockets trapped therein will lead to a more constant degree of buoyancy of the floats thereby enhancing the overall performance of the dual flush valve 110. As indicated previously, the stem 36 is hollow. Its open upper end serves as a cistern overflow to allow water to escape from the cistern in the event of overfilling. In another modification, the stem could be of telescopic construction to allow its upper end to be raised or lowered to suit a particular cistern and the desired flush volume.

Claims: CLAIMS 1. A toilet cistern dual flush valve operable selectively in a full flush mode in which a relatively large volume of water is discharged from the cistern or a partial flush mode in which a relatively small volume of water is discharged from the cistern, the valve comprising: a valve stem carrying a valve closure seatable on an outlet from the cistern and movable between a raised, open position in which the closure is spaced from the outlet and a lowered, closed position in which the closure seats on the outlet, means operable in both full and partial flush modes to raise the stem, operatively buoyant means attached to the stem which in the full flush mode maintains the stem in the open position until the relatively large volume of water has been discharged and the buoyant means loses buoyancy whereafter the stem descends under gravity to the closed position, and means which operates in the partial flush mode to add sufficient further mass to the stem when the relatively small volume of water has been discharged, to cause the stem to descend to the closed position. 2. A toilet cistern dual flush valve according to claim 1 wherein the means operable to raise the stem includes actuators that are selectively, manually operable to initiate the full or the partial flush mode. 3. A toilet cistern dual flush valve according to claim 2 wherein the actuators are actuating handles. 4. A toilet cistern dual flush valve according to claim 2 wherein the actuators are actuating buttons. 5. A toilet cistern dual flush valve according to any one of claims 1 to 4 wherein the operatively buoyant means includes a main float. 6. A toilet cistern dual flush valve according to any one of claims 1 to 5 wherein the means which operate in the partial flush mode to add further mass to the stem includes an upper float unit. 7. A toilet cistern dual flush valve according to any one of claims 1 to 6 wherein the valve stem includes upper and lower collars. 8. A toilet cistern dual flush valve according to any one of claims 2 to claim 7 including linkages extending between the actuators and the upper float unit such that operation of either actuator raises the upper float unit into abutment with an upper collar on the stem thereby raising the stem to the open position. 9. A toilet cistern dual flush valve according to claim 8 wherein the linkages include a toggle attachable pivotally to the upper float unit, the toggle including a detent such that operation of the relevant actuator to initiate a partial flush causes the toggle to pivot to a position in which , the detent engages the lower collar and adds the mass of the upper float unit to the valve stem when water in the cistern has dropped to a level at which the upper float unit loses buoyancy. 10. A toilet cistern dual flush valve according to claim 9 wherein the upper float unit includes a water reservoir to accommodate a volume of water to provide gravitational mass. 11. A toilet cistern dual flush valve according to any one of claims 5 to 10 wherein the main float and/or the upper float unit include inverted cup shapes to accommodate air. 12. A toilet cistern dual flush valve according to any one of claims 5 to 10 wherein the inverted cup shapes of the main float and/or the upper float unit include closed cell foam. 13. A toilet cistern dual flush valve according to any one of claims 7 to 12 wherein each linkage includes a telescopic construction to lengthen or shorten the linkage. 14. A toilet cistern dual flush valve according to claim 13 wherein the telescopic construction includes a catch and a ratchet. 15. A toilet cistern dual flush valve substantially as herein described and illustrated in the drawings.

Inventors: BASSIL JOHN CLARK, SUTHERLAND JOHN NICOLL, TICKLE KARL THOMAS, VAN ZYL CHRISTIAAN, WELSH ANTHONY ROSS, BASSIL, JOHN, CLARK, SUTHERLAND, JOHN, NICOLL, TICKLE, KARL, THOMAS, VAN ZYL, CHRISTIAAN, WELSH, ANTHONY, ROSS
Applicants: BASSIL JOHN CLARK, DUTTON PLASTICS ENGINEERING PT, SUTHERLAND JOHN NICOLL, TICKLE KARL THOMAS, VAN ZYL CHRISTIAAN, WELSH ANTHONY ROSS, BASSIL, JOHN, CLARK, DUTTON PLASTICS ENGINEERING (PTY) LTD, SUTHERLAND, JOHN, NICOLL, TICKLE, KARL, THOMAS, VAN ZYL, CHRISTIAAN, WELSH, ANTHONY, ROSS
Application year: 2001
Main classification: E03D1
IPC codes: E03D1