AU2005201563A1 - Lavatory flushing cistern - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT LAVATORY FLUSHING CISTERN The following statement is a full description of this invention, including the best method of performing it known to me: LAVATORY FLUSHING CISTERN This invention relates to an improved method of controlling the flow of flushing water from lavatory cisterns to lavatory bowls.

Lavatory flushing cisterns currently in use fall into two main categories; The siphonic cistern, in which part of the outlet pipe through which the flushing water flows from the cistern to the lavatory bowl extends above the full water level of the cistern in such a manner that, by manually causing water to be pushed or drawn from the cistern into the inlet of the pipe near the bottom of the cistern, siphonic action will commence and continue until the cistern is substantially empty, thus flushing the bowl.

This cistern can be characterised as inherently leak proof because it does not rely on a moving seal or the like to prevent water from flowing from the cistern to the bowl when flushing is not taking place.

Initiation of siphonic action requires that a considerable quantity of water must be pushed or drawn upward and through the topmost section of the outlet pipe, which requires the application of a relatively large manual force.

It is a characteristic of this cistern that the flow of flushing water begins relatively slowly which is considered detrimental to the achievement of effective flushing using the minimum quantity of flushing water.

The valve cistern, in which the flow of water from the cistern to the bowl is controlled by a valve consisting of a plug or washer of resilient material in such a position within the cistern that it can be moved by a manual operating mechanism to open and close a hole in the outlet socket at the bottom of the cistern which connects to a pipe leading to the lavatory bowl.

This cistern allows flushing to be initiated by the application of a smaller manual force than that required by the siphonic cistern, and provides a rapid beginning and end of the flow of flushing water.

For these reasons, the valve cistern has almost universally replaced the older siphonic cistern.

The valve cistern is not inherently leak proof due to its reliance on a watertight seal being formed between the resilient plug or washer and its seat on the outlet socket after each flushing operation, and it has been found in practice that it can leak for one or more of several reasons, such as foreign particles becoming lodged between the plug or washer and its seat, incorrect alignment between the plug or washer and its seat due to wear of its guidance mechanism, or roughness or cracking of the surface of the resilient material of which the plug or washer is made.

To conserve water, a need exists for a cistern which is inherently leak proof, and which provides a rapid beginning and end of the flow of flushing water. In addition, it is desirable that it should have full and partial flushing capability, and be capable of being operated by a relatively small manual force.

This invention fulfils these needs in the following manner: A lavatory cistern is provided which is filled with water by a float controlled inlet valve and has a pipe or other form of connection from the outlet socket at the bottom of the cistern to the flushing inlet at the rear of the bowl in the usual manner.

Within the cistern is a flow control device comprising an outlet pipe connected to an outlet socket in the bottom of the cistern by a flexible waterproof connecting pipe located substantially at the bottom of the cistern thereby allowing the outlet pipe to be moved up and down within the cistern in such a manner as to allow the gravitational flow of water from the cistern to the lavatory bowl by causing the open end of the outlet pipe to move below the surface of the water in the cistern and to stop the flow of water by causing the open end of the outlet pipe to move above the surface of the water in the cistern.

An upward force is provided by some means, such as a buoyancy compartment or device formed in or attached beneath the outlet pipe adjacent to its open end, or by a spring acting upon the pipe either directly or by a mechanical linkage, or by a counterweight or the like, sufficient to ensure that the open end of the pipe is held above the surface of the water in the cistern at all levels within the normal operating range of the cistern when the outlet pipe is not being manually pushed downward or mechanically restrained from moving upward.

The flexible connecting pipe may be made of rubber or any suitable waterproof flexible material and may be formed into bellows or otherwise shaped in such a manner as to increase its flexibility and to maintain its circular cross section when bent.

One or two guidance arms may be attached to or formed in one or both sides respectively of the outlet pipe, the arm or arms extending outward from the pipe and thence parallel to its axis to a point past the midpoint of the flexible connecting pipe and being rotationally attached to an extension or extensions attached to or formed in the outlet socket by an axle or axles, the axis of rotation being in the horizontal plane and intersecting the axis of the flexible connecting pipe at its centre, in such a manner as to constrain the movement of the outlet pipe to an arc in the vertical plane.

The outlet socket may have a bend adjacent to the flexible connecting pipe in such a manner that when straight the flexible connecting pipe and the outlet pipe extend from the bend to a point approximately at the centre of the outlet pipe's arc of travel, thereby allowing use to be made of the connecting pipe's flexibility upward and downward from its straight position.

A stop or the like is provided to prevent any further upward travel of the outlet pipe if the water level in the cistern rises above normal, thereby allowing the pipe to act as an overflow.

A means of operation is provided, such as a vertically positioned push rod which is free to move up and down and is connected to the outlet pipe's attached guidance arm or arms by means of a mechanical linkage or linkages in such a manner that, when the cistern is filled with water, a push button situated above the push rod, normally held in its top position by a spring or similar means with its bottom end a short distance above the top end of the push rod, can be manually pushed downward, pushing the rod downward and thus causing the outlet pipe to be pushed below the water level to the bottom limit of its travel substantially at the bottom of the cistern, thereby allowing water to flow under the influence of gravity through the outlet pipe from the cistern to the bowl. When the push rod reaches its bottom limit of travel, a float situated substantially at the bottom of the cistern operates a restraining mechanism such as a pawl which engages with a ratchet or the like on the push rod, in such a manner as to hold the push rod in its bottom position when the manual force is removed.

When the amount of water required for a full flush has flowed from the cistern, the water level falls below the float, the weight of which releases the restraining mechanism, allowing the push rod to move upward thereby allowing the open end of the outlet pipe to move upward above the surface of the water in the cistern, preventing the further flow of water from the cistern to the bowl. The cistern is refilled with water by the float controlled inlet valve.

To provide a cistern which has dual flushing capability, another float is provided which operates a second restraining mechanism on the push rod in a manner similar to that previously described, this float being situated at such a position in the cistern that its weight releases the restraining mechanism when the amount of water required for a partial flush has flowed from the cistern.

The ratchet of the second restraining mechanism is at such a position on the push rod that its pawl will engage with the ratchet a relatively short distance before the push rod reaches its bottom limit of travel.

A second push button is situated above the aforementioned vertical push rod, this push button having a larger gap between its bottom end and the top of the push rod than the first mentioned push button, the gap being sufficient to allow the second push button to be used to push the push rod downward far enough to allow the second restraining mechanism to function but not far enough to allow the first mentioned restraining mechanism to function, thereby allowing the second push button to initiate a partial flush but not to initiate a full flush.

It will be realised that many variations of the flush initiation and selection mechanisms are possible, and that these do not change the essence of the invention, which resides in the use of a flexibly mounted outlet pipe to control the gravitational flow of water from the cistemrn to the bowl by changing the vertical position of the open end of the pipe relative to the surface of the water in the cistern, and the use of an upward force provided by buoyancy or by a spring or a counterweight, to keep the open end of the pipe above the surface of the water in the cistern between flushing operations.

To assist with understanding the invention, reference will now be made to the accompanying drawings which show one example of the invention.

In the drawings: FIG. 1 shows a front view of a lavatory flushing cistern according to this invention; FIG. 2 shows an enlarged front view of the operating and flush selection mechanisms.

FIG. 3 shows an alternative arrangement of the flush selection mechanism.

Some stationary parts such as the support structure and operating and flush selection mechanism guides and the like have been omitted from the drawings for clarity.

The flushing flow control device is shown with its moving parts in the positions they would be in when not flushing and with cistern 7 approximately 75% full of water.

Float controlled inlet valve 35 keeps cistemrn 7 filled with water to full operating level 32 between flushing operations and outlet socket 3 is connected to the lavatory bowl by any suitable means such as a pipe or the like in the usual manner.

Outlet pipe 1 has float 5 attached on its under side adjacent to its open end 6 and is connected by flexible connecting pipe 2 to bent section 4 of outlet socket 3.

Guidance arm 8 is attached to outlet pipe 1 and extends outward clear of, and toward the centre of, flexible connecting pipe 2 and is rotatably attached to axle 9 which is supported by an extension (not shown) of outlet socket 3 in such a manner that the axis of rotation horizontally intersects the midpoint of the centreline of flexible connecting pipe 2 at 900 allowing outlet pipe 1 to move in a vertical arc.

Flush initiation push rod 14 is slideably supported by top guide 16 and bottom guide 17 formed in the aforesaid extension of outlet socket 3.

Link 15 is rotatably attached by pin 30 to push rod 14 and by pin 31 to guidance arm 8.

Outlet pipe 1 is prevented from rising above its top position 10 by stop 11 and prevented from moving below its bottom position 12 by the underside of the flat plate 13 attached to or formed on the top of push rod 14 coming into contact with the top of push rod top guide 16, thereby preventing further downward movement of push rod 14, attached link 15 and outlet pipe guidance arm 8.

Full flush push button 18 is normally held in its top position by spring 20 and can be manually pushed downward sufficiently far to cause its bottom end 36 to push flat top 13 of push rod 14, push rod 14 and link 15 fully downward thereby causing outlet pipe guidance arm 8 to move outlet pipe 1 from its top position 10 to its bottom position 12, at which position push rod 14 is in such a position as to allow the buoyancy of full flush cut off float 23 to rotate attached pawl 27 anti-clockwise about pin 29 causing pawl 27 to engage in ratchet 28 formed in push rod 14 thereby holding outlet pipe 1 in its bottom position when the manual operating force is removed.

Water flows into open end 6 of outlet pipe 1 to the lavatory bowl until the water level in cistern 7 reaches full flush cut off level 34 at which level the weight of full flush cut off float 23 rotates attached pawl 27 clockwise about pin 29 causing pawl 27 to disengage from ratchet 28, thereby allowing the buoyancy of float 5 to move open end 6 of outlet pipe 1 above the level of the water in cistern 7, thereby preventing the further flow of water from cistern 7 to the lavatory bowl.

Part flush push button 19 is normally held in its top position by spring 21 and can be manually pushed downward sufficiently far to cause its bottom end 37 to push flat top 13 of push rod 14, push rod 14 and link 15 downward thereby causing outlet pipe guidance arm 8 to move outlet pipe 1 from its top position 10 to a lower position below the part flush cut off level 33 at which position push rod 14 is in such a position as to allow the buoyancy of part flush cut off float 22 to rotate attached pawl 24 anticlockwise about pin 26 causing pawl 24 to engage in ratchet 25 formed in push rod 14 thereby holding outlet pipe 1 in the said lower position when the manual operating force is removed.

Part flush button 19 is shorter than full flush push button 18 thereby providing sufficient space between its bottom end 37 and flat top 13 of push rod 14 to prevent manual pressure on part flush push button 19 from moving push rod 14 far enough downward to allow pawl 27 to engage in ratchet 28.

Water flows into open end 6 of outlet pipe 1 to the lavatory bowl until the water level in cistern 7 reaches part flush cut off level 33 at which level the weight of part flush cut off float 22 rotates attached pawl 24 clockwise about pin 26 causing pawl 24 to disengage from ratchet 25, allowing the buoyancy of float 5 to move open end 6 of outlet pipe 1 above the level of the water in cistern 7, preventing the further flow of water from cistern 7 to the lavatory bowl.

Figure 3 shows an alternative construction in which the push buttons 18 and 19 are identical to each other and spacing piece 38 is provided which can be removably attached to flat end 13 of push rod 14 in alignment with either of push buttons 18 or 19 by projection 39 which is an interference fit in holes 40 and 41 thereby allowing the transfer of the full and part flush functions between the push buttons.

A lavatory flushing flow control device is hereby provided which is inherently leak proof and can be operated by a relatively small operating force, provides a rapid beginning and end of the flow of flushing water, and provides a full flush and part flush facility.