AU2008301209B2

AU2008301209B2 - A pneumatic button assembly for a cistern outlet valve

Info

Publication number: AU2008301209B2
Application number: AU2008301209A
Authority: AU
Inventors: Sam Robertson England
Original assignee: Caroma Industries Ltd
Current assignee: Caroma Industries Ltd
Priority date: 2007-09-20
Filing date: 2008-08-29
Publication date: 2014-07-03
Anticipated expiration: 2028-08-29
Also published as: WO2009036490A1; NZ583973A; CN101802315A; CN101802315B; AU2008301209A1

Abstract

A pneumatic button assembly (10) for a cistern outlet valve. The assembly comprising a base (12), a button (14), a first guide member (18), a second guide member (20), and a flexible diaphragm (22). The button (14) is biased away from the base (12) and has an external face (14a). The first guide member (18) extends from the button (14), away from the external face (14a). The second guide member (20) extends from the base (12), and is adapted to slidably engage with the first guide member (18). The flexible diaphragm (22), around the first and second guide members (18, 20), extends between the base (12) and the button (14).

Description

1 A PNEUMATIC BUTTON ASSEMBLY FOR A CISTERN OUTLET VALVE Technical Field The present invention relates to pneumatic button assembly for a cistern outlet valve. A cistern is known as a flush tank in the USA. Background of the Invention Pneumatic button assemblies are commonly used with remotely installed cisterns, such as cisterns concealed within a wall cavity. Known button assemblies include a flexible diaphragm which is compressed by the pressing of a button and a cylinder which moves within a cylindrical bore. When the button is pressed, air within the diaphragm is forced through a flexible line which is connected to a mechanical actuator operable on the cistern outlet valve. In order to avoid cocking and jamming of the button in the bore, the length to width ratio of the button should be at least 1.5. For example, a button with a diameter of 40 mm should have a guidance length of at least 60 mm. A disadvantage of known pneumatic button assemblies is they require a relatively large housing to accommodate the button, which limits installation applications. Object of the Invention It is the object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages. Summary of the Invention Accordingly the present invention provides a pneumatic button assembly for a cistern outlet valve, the assembly comprising: a base; a button having an external face; a spring biasing the button away from the base; la a first guide member extending from the button, away from the external face; a second guide member extending from the base, and adapted to slidably engage the first guide member; and a flexible diaphragm, around the first and second guide members, extending between the base and the button; wherein the spring is located within the flexible diaphragm and at least partially around the first and the second guide members. The diaphragm preferably has concertina style side walls.

WO 2009/036490 PCT/AU2008/001290 2 The first guide member is preferably a longitudinally extending cylindrical pin which is slidably received within the second guide member, which is preferably a longitudinally extending cylindrical recess. The assembly preferably includes a housing between the base and the button and 5 around the diaphragm. The housing preferably includes an inwardly facing flange adapted to limit movement of the button away from the base. The base preferably includes a pneumatic outlet in fluid communication with the diaphragm. The button is preferably circular and includes a one-way valve adapted to allow 1o air to enter the diaphragm. The one-way valve preferably includes an opening in the button closable by a portion of the diaphragm. Brief Description of the Drawings A preferred embodiment of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein: 15 Fig. l is a cross sectional side view of an embodiment of a pneumatic button assembly prior to actuation; and Fig. 2 is a cross sectional side view of the pneumatic button assembly shown in Fig. 1 after actuation. Detailed Description of the Preferred Embodiment 20 Figs. 1 and 2 show a button guide assembly 10 for the outlet valve of a remotely located cistern (not shown). The assembly 10 includes a generally cylindrical base 12 and a button 14. The button 14 has a circular external face 14a and is biased away from the base 12 by a spring 16. The assembly 10 also includes a first guide member, in the form of a cylindrical pin 18, and a second guide member, in the form of a cylindrical recess 20. 25 A flexible diaphragm 22 is positioned around the cylindrical pin 18 and the recess 20 and has concertina side walls 22a extending between the base 12 and the button 14. The spring 16 is also located within the diaphragm 22. The button 12 includes a pair of one-way valves 24, which are adapted to only allow air to enter the interior of the diaphragm 22. The one-way valves 24 each include 30 an opening 24a in the button face 14a closable by an edge portion 22b of the flexible diaphragm 22.

WO 2009/036490 PCT/AU2008/001290 3 A housing 26 extends between the base 12 and the button 14 external to the diaphragm 22. The housing 26 includes an inwardly directed flange 26a which is adapted to limit movement of the button 14 away from the base 12. The base 12 also includes a pneumatic outlet 28, in fluid communication with the 5 interior of the diaphragm 22. The base 12 has a cylindrical collar 12a around the recess 20 which includes a ridge 12b adapted to limit the movement of the button 14 away from the flange 26a. The button 14, the base 12, and the cylindrical pin 18 are injection moulded from ABS. The spring 16 is produced from a spring grade steel. The diaphragm 22 is 10 produced from an elastomeric material. The operation of the button guide assembly 10 will now be described. Fig. 1 shows assembly 10 prior to actuation, at which time the interior volume of the diaphragm 22 is filled with air. When the button 14 is (manually) depressed towards the position shown in Fig. 2, the air within the diaphragm 22 is forced out through the pneumatic is outlet 28 to activate the outlet valve and thus flush the cistern. During this movement, the valves 24 are closed by the diaphragm portion 22b being forced outwardly against the openings 24a, closing same. Fig. 2 shows the button guide assembly 10 after actuation. When the button 14 is released, the spring 16 drives the button 14 back towards the position shown in Fig. 1, 20 until it reaches the flange 26a. If any air has leaked from the button assembly 10, the actuator in the cistern or the lines between these components, then during movement of the button 14 towards the position shown in Fig. 1, the diaphragm portions 22b flex inwardly away from the openings 24a and allow air to enter the diaphragm 22. The movement of the button 14 between the end positions shown in Figs. 1 and 2 25 is guided by the end of the cylindrical pin 18 sliding longitudinally within the cylindrical recess 20 and the point contact of the button 14 on the housing 26. The length to width ratio of the pin 18 and the recess 20 exceeds the 1.5:1 ratio required to prevent the pin 18 from cocking or jamming in the recess 20, which thus prevents cocking or jamming of the button 14. 30 Further, in the known assemblies previously discussed, the button has guidance, in the form a cylindrical wall, around the outside of the diaphragm that extends at least 1.5 times the button diameter down inside the housing. Such guidance is not required in the assembly 10 due to the button movement being predominantly controlled by the pin 18 being guided within the recess 20. As a result, the button assembly 10 has an overall 35 length which, for a given button diameter, is relatively small.

WO 2009/036490 PCT/AU2008/001290 4 A reduction in button diameter is also achieved as the cylindrical wall required outside of the diaphragm in the known assemblies is not required in the assembly 10. The button assembly 10 is thus easier to fit in a variety of installations. Although the invention has been described with reference to a specific example, 5 it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. For example, the button 14, the base 12, and the cylindrical pin 18 can be injection moulded from other materials, such as acetal or polyester. These components can also be machined or die cast in metal.

Claims

1. A pneumatic button assembly for a cistern outlet valve, the assembly comprising: a base; a button having an external face; a spring biasing the button away from the base; a first guide member extending from the button, away from the external face; a second guide member extending from the base, and adapted to slidably engage the first guide member; and a flexible diaphragm, around the first and second guide members, extending between the base and the button; wherein the spring is located within the flexible diaphragm and at least partially around the first and the second guide members.

2. The assembly as claimed in any one of claim 1, wherein the diaphragm has concertina style side walls.

3. The assembly as claimed in claim 1 or 2, wherein the first guide member is slidably received within the second guide member.

4. The assembly as claimed in claim 3, wherein the first guide member is a longitudinally extending cylindrical pin.

5. The assembly as claimed in claim 4, wherein the second guide member is a longitudinally extending cylindrical recess.

6. The assembly as claimed in any one of claims 1 to 5 further comprising a housing between the base and the button and around the diaphragm.

7. The assembly as claimed in claim 6, wherein the housing includes an inwardly facing flange adapted to limit movement of the button away from the base.

8. The assembly as claimed in any one of claims 1 to 7, wherein the base includes a pneumatic outlet in fluid communication with the diaphragm. 6

9. The assembly as claimed in any one of claims 1 to 8, wherein the button is circular.

10. The assembly as claimed in any one of claims 1 to 9 wherein the button includes a one way valve adapted to allow air to enter the diaphragm.

11. The assembly as claimed in claim 10, wherein the one-way valve includes an opening in the button closable by a portion of the diaphragm. Caroma Industries Limited Patent Attorneys for the Applicant SPRUSON & FERGUSON