GB2310440A - Modified siphon piston rod - Google Patents

Abstract

A modified siphon piston rod for use in a siphon of a WC cistern allows either a normal or short flush, the modified siphon piston rod comprising a lower end (15b) for attachment to a diaphragm (14) in an up leg (12) of the siphon and an upper end (15a) arranged so as to protrude through a hole (12a) in the siphon, wherein there is provided between said upper and lower ends means (15c) for permitting air to enter the siphon before the water level reaches the bottom of the up leg. Preferably a section of the rod is suitably narrowed or shaped in such a way as to provide an air passage between the rod and the hole in the siphon up leg through which the rod passes. Alternatively a normal plastic piston rod may be formed with one or more apertures between the two ends.

Description

REDUCED VOLUME FLUSH FOR SIPHON DISCHARGE CISTERN The present invention relates to apparatus for permitting a reduced volume or "short" flush from a siphon discharge WC cistern, for the purposes of saving water, and to a method of fitting the apparatus to an existing cistern.

Previous attempts to effect a short flush have been unsuccessful, primarily because the mechanical arrangements have been such that the cistern lever handle needed to be operated in other than conventional manner in order to effect a normal flush. Thus, a person not knowing that the cistern in question included such an arrangement would not be able to flush the WC normally, and would then repeat the flush, defeating the object of saving water.

The present invention seeks to overcome this difficulty by providing a different mechanical arrangement which effects a full flush in response to normal operation of the lever handle, and effects and alternative short flush only upon operating the handle in a particular specified way.

A conventional siphon comprises an up leg and a down leg, the up leg having a diaphragm located therein and attached generally in the centre to the lower end of a siphon piston rod. The other end of the siphon piston rod is attached to the cistern lever, the rod passing through a hole in the up leg of the siphon. When the lever handle is depressed, the diaphragm is pulled upwards inside the siphon, causing water to be discharged through the down leg into the WC bowl. Thereafter, the diaphragm is urged downwards again by means of a spring located around the rod, between the diaphragm and the siphon.

When the water level in the cistern falls below the bottom of the up leg, air enters the siphon preventing further siphoning action and the cistern refills via the ball valve to the normal water level.

According to a first aspect of the present invention there is provided a modified siphon piston rod for use in a siphon of a WC cistern allows either a normal or short flush, the modified siphon piston rod comprising a lower end for attachment to a diaphragm in an up leg of the siphon and an upper end arranged so as to protrude through a hole in the siphon wherein there is provided between said upper and lower ends means for permitting air to enter the siphon before the water level reaches the bottom of the up leg.

This may take the form of a section of the rod which is narrowed or shaped in such a way as to provide an air passage between the rod and the hole in the siphon up leg through which the rod passes.

The preferred embodiment comprises a narrow steel spindle onto which is moulded or attached plastic first and second end sections, the latter being tapered from full, normal piston rod width to the width of the steel spindle.

Alternatively, a normal plastic piston rod could be formed with one or more apertures between the two ends.

The narrowed, shaped or apertured region may be in the middle of the rod, in which case the handle would have to be held in a middle or intermediate position to break the siphon and effect the short flush, or, as this may be difficult to do in practice, the narrowed, shaped or apertured region may be closer to the lower end of the rod, i.e the end attached to the diaphragm, such that the handle would need to be held in the fully depressed position to effect the short flush.

A further alternative would be to provide an otherwise normal rod with its middle or lower region formed into a particular pattern such as a cross or spiral.

According to a second aspect of the present invention there is provided a method of adapting a conventional WC siphon to one with dual flush capability, the method comprising providing attaching a lower end of a modified siphon piston rod to the siphon diaphragm in an up leg of the siphon and arranging the upper end of said modified piston rod so that it protrudes through a hole in the siphon, wherein there is provided between said upper and lower ends of the modified rod means for permitting air to enter the siphon before the water level reaches the bottom of the up leg.

The modified rod of the present invention may be fitted in place of a conventional rod, or alongside it. The latter would involve forming a second hole in the siphon and providing another attachment point in the diaphragm.

Where the modified piston rod is fitted in place of the existing rod, the top of the upper end of the modified piston rod is attached to the cistern operating handle, such that depressing the handle fully and releasing it straight away causes a normal flush as the uppermost, normal width end seals the hole in the siphon when the handle is released. However, if instead of releasing the handle straight away it is held approximately midway between the two positions, this exposes an air gap between the modified middle section of the piston rod and the hole in the siphon through which it passes. When the water level in the cistern reaches this point, air will be admitted through this gap thus breaking the siphon prematurely, giving the required short flush.Upon releasing the handle a spring, located around the modified rod as it would have been around a conventional rod, urges the diaphragm downwards until the upper normal width region seals the hole following which the cistern fills up to normal level again. As an alternative to the spring, other means can be used to urge the diaphragm downwards, for example a weight associated with the rod acting under gravity. Similarly, if the narrowed portion is at the lower end of the rod, the short flush is achieved by holding the handle in the fully depressed position.

When used alongside a conventional piston rod, the modified rod works in a very similar way, but without the need for the spring which is already present around the existing conventional rod, the latter being attached to the cistern operating handle. Upon depressing the handle to lift the conventional rod, the adjacent modified rod is also caused to move upwards with the diaphragm and can be held in a position which allows air to enter the siphon prematurely, as described in the foregoing paragraph, by holding the lever handle in a middle or lowermost position, until the siphon is broken.

According to a third aspect of the present invention there is provided a siphon for use within a WC cistern the siphon including a modified siphon piston rod comprising a lower end attached to a diaphragm in an up leg of the siphon and an upper end arranged so as to protrude through a hole in the siphon wherein there is provided between said upper and lower ends means for permitting air to enter the siphon before the water level reaches the bottom of the up leg.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates the sequence of events during normal and short flushing of a siphon according to the present invention, Figure 1A shows the detail of the air gap between the modified rod and the hole in the siphon, Figure 2 illustrates an alternative version including both conventional and modified rods, Figure 3 illustrates the preferred shape of the modified rod, Figure 4 illustrates four alternative shapes for the modified rod, and Figure 5 illustrates a variation of the arrangement shown in Figure 2, Figures 5A and 5B illustrate the sequence of events in a short flush with the arrangement shown in Figure 5.

Referring to Figure 1, a siphon 10 (including up leg 12 and down leg 11) for use within a WC includes a diaphragm 14 to which is connected to the bottom end of a modified piston rod 15, illustrated in more detail in Figure 3. The rod passes through a hole 12a in the wall of the up leg 12 of the siphon, and the upper end of rod 15 is connected via link 13 to the cistern operating lever (not shown). The rod 15 comprises normal width top and bottom ends 15a, 15b respectively, with a narrowed section 15c therebetween. This may take the form of a steel spindle onto which ends 15a, 15b are moulded, or alternatively an entirely plastic rod may be provided, including either an oval aperture 16, a reduced cross section such as 17 or 18, a hollow section 19 or a spiral cut away pattern such as 20.

In Figure 1, the first two illustrations relate to normal flushing of the cistern - the handle is depressed completely causing the diaphragm 14 to move upwards so that the water in the cistern starts siphoning through siphon 10 into the WC bowl, through down leg 11. If the handle is release straight away, the spring 23 urges the rod downwards, as shown in the last illustration in Figure 1, until the top end 15a seals the hole 12a. In this circumstance, the water will continue to siphon until the water level reaches the bottom of the up leg 12, whereupon air will enter and the siphon will be broken, allowing the cistern to refill. However, if the handle is held in a middle position instead of releasing it fully, the rod 15 assumes a corresponding middle position as shown in the third illustration of Figure 1 and in Figure 1A.In this position, the narrowed middle region 15c creates an air gap between the rod and the hole 12a, allowing air to enter when the water level reaches the level of hole 12a, thus breaking the siphon prematurely thereby effecting a short flush. The user would notice the sound of the siphon breaking, whereupon the handle may be released fully, allowing the diaphragm 14 to be urged downwards again and the cistern to be refilled.

As illustrated in Figure 2, the modified piston rod may be used alongside a conventional rod 30, the latter incorporating a spring 30 for the same purpose as described previously. The conventional rod 30 passes through hole 30a and is coupled to the cistern operating lever, and the diaphragm, and the modified rod is attached at its lowermost end 15b to the diaphragm 14, passes through hole 12a with its upper end 15a sealing hole 12a. In this arrangement, a short flush can be effected in the same way as described previously, by holding the handle in a middle position until the siphon is broken by the admission of air through the gap between the modified rod 15 and the hole 12a in the siphon.

The modified piston could be incorporated either instead of or in addition to a conventional piston at the point of manufacture, but it is also ideally suited to retro-fitting to an existing siphon, to convert a conventional cistern to a dual flushing cistern.

Whilst the steel spindle embodiment of Figure 3 is preferred as it breaks the siphon in a more positive way, many other variations are possible, some of which are illustrated in Figure 4, as long as there is the possibility of maintaining an air gap between the rod and the hole 12a during siphoning.

In Figure 5, instead of the narrowed portion being in the middle region, the lower region 24c of the rod 24, i.e that region adjacent the diaphragm attachment end 24c, is narrowed, with a relatively longer normal width section 24a. In this arrangement, a short flush is effected as shown in Figure 5A when the cistern lever or handle is held fully depressed during the flush, such that the narrowed lower region 24c of rod 24 protrudes through hole 12a, allowing air intake when the water level reaches the hole 12a.

Normal operation of the handle, i,e depressing the handle and immediately releasing it again to effect a full flush, is shown in Figure SB. The spring 22 causing the diaphragm 14 to be pushed downwards and causing the normal width portion 24a of rod 24 to protrude through and effectively seal off the hole 12a.

Claims (13)

1. A modified siphon piston rod for use in a siphon of a WC cistern allows either a normal or short flush, the modified siphon piston rod comprising a lower end for attachment to a diaphragm in an up leg of the siphon and an upper end arranged so as to protrude through a hole in the siphon, wherein there is provided between said upper and lower ends means for permitting air to enter the siphon before the water level reaches the bottom of the up leg.

2. A rod according to Claim 1 wherein a section of the rod which is narrowed or shaped in such a way as to provide an air passage between the rod and the hole in the siphon up leg through which the rod passes.

3. A rod according to Claim 1 or Claim 2 and comprising a narrow steel spindle onto which is moulded or attached plastic first and second end sections, the latter being tapered from full, normal piston rod width to the width of the steel spindle.

4. A rod according to Claim 1 and comprising a normal plastic piston rod formed with one or more apertures between the two ends.

5. A rod according to any of the preceding Claims, wherein the narrowed, shaped or apertured region is in the middle of the rod such that the handle is held in a middle or intermediate position to break the siphon and effect the short flush.

6. A rod according to any of Claims 1 to 4, wherein the narrowed, shaped or apertured region is closer to the lower end of the rod, i.e the end attached to the diaphragm, such that the handle is held in the fully depressed position to effect the short flush.

7. A rod according to any of the preceding Claims, wherein an otherwise normal rod has its middle or lower region formed into a particular pattern such as a cross or spiral.

8. A method of adapting a conventional WC siphon to one with dual flush capability, the method comprising providing attaching a lower end of a modified siphon piston rod to the siphon diaphragm in an up leg of the siphon and arranging an upper end of the rod so that it protrudes through a hole in the siphon, wherein there is provided between said upper and lower ends of the modified rod means for permitting air to enter the siphon before the water level reaches the bottom of the up leg.

9. A method according to Claim 8 wherein the modified rod of the present invention is fitted either in place of a conventional rod, or alongside it.

10. A siphon for use within a WC cistern the siphon including a modified siphon piston rod comprising a lower end attached to a diaphragm in an up leg of the siphon and an upper end arranged so as to protrude through a hole in the siphon, wherein there is provided between said upper and lower ends means for permitting air to enter the siphon before the water level reaches the bottom of the up leg.

11. A modified siphon piston rod substantially as herein described and illustrated in the accompanying drawings.

12. A method of adapting a conventional WC siphon to one with dual flush capability, the method being substantially as herein described and illustrated in the accompanying drawings.

13. A siphon substantially as herein described and illustrated in the accompanying drawings.