Technical Field of the Invention

The present invention relates to a tap fitting.

Background to the Invention A common tap fitting is a push tap which is used to control the amount of water that is dispensed from a faucet. They are particularly popular in public bathrooms where it is desirable to control how much water is dispensed by the taps by users of the bathroom. Push taps typically comprise a cap which may be depressed to open a faucet and allow water to flow. When the cap is released it returns gradually to a closed position under hydraulic pressure so that further flow of water is restricted.

A problem with existing push taps is that they can be tampered with in such away that the cap is permanently depressed thereby causing water to flow indefinitely. This can be very wasteful and can lead to flooding. Hydraulic based push taps also become less effective when the number of taps in a given bathroom is increased. If all taps are activated at the same time, the water pressure urging the caps back to the closed position is reduced which affects the time delay on the push tap and therefore causes excessive volumes of water to be dispensed. It is also difficult to vary the time delay (i.e. time taken for the push tap to return from an open position to a closed position) and flow rate on hydraulic based push taps. It is an object of the present invention to provide an improve tap fitting.

Summary of the Invention According to a first aspect of the present invention, there is provided a tap fitting comprising a body and a spindle, the body comprising a bore through which the spindle extends, the spindle being movable relative to the body within the bore, the body further comprising at least one aperture which opens into the bore such that a fluid flow path is defined between the bore and the aperture through the body, the spindle being operable between a closed position in which the fluid flow path is closed and an open position in which the fluid flow path is open, wherein the fitting further comprises a first cap arranged relative to the body such that the first cap and body together define a first space, the fitting further comprising a second cap arranged relative to the first cap to define a second space, and wherein the first space is linked to the second space such that fluid can flow between the first space and the second space, wherein operation of the tap fitting evacuates fluid from the first space to the second space.

Advantageously, the cap need not have any externally visible holes or apertures through which air may flow to and from the first space. Thus, the appearance of the tap fitting is not compromised by any such holes and the path along which air may flow to and from the first space is less likely to become clogged or blocked by external contaminants such as soap and mildew.

One end of the cap may define a first surface which may be pushed to urge the cap toward the body and the opening may be directed away from the first surface. The two spaced apart walls may each comprise a free end and the opening may be defined between the free ends. The opening may be substantially annular.

The cap may comprise an inner part and an outer part and the inner part and outer part may be separable. The fitting may further comprise a seal arranged between the cap and the body, wherein the seal further defines the space. The seal may comprise perfluoropolyether.

The fitting may further comprise a spindle arranged to extend through the body, wherein the spindle comprises a channel along which fluid may flow between the space and the pathway. The channel may comprise a valve to control the flow of fluid through the channel.

The body may define a fluid flow path and the fitting may further comprise a connector having two openings, wherein the connector is mounted to the body such that the fluid flow path extends through the connector and wherein the connector is removably mounted to the body so that different connectors with different sized openings can be mounted to the body to adjust the size of the fluid flow path.

The pathway may open out to outside the fitting.

The spindle may be biased toward the closed position.

Detailed Description of the Invention In order that the invention may be more clearly understood an embodiment/embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a cross section view of a fitting according to the invention; Figure 2 shows a perspective view of the body of the fitting shown in Figure 1; Figure 3 shows a cross section view of the body shown in Figure 2;

Figure 4 shows a perspective view of the spindle of the fitting shown in Figure 1; Figure 5 shows a cross section view of the spindle shown in Figure 4; Figure 6 shows an enlarged view of an end of the spindle shown in Figure 5;

Figure 7 shows a perspective view of the bellows of the fitting shown in Figure 1 ;

Figure 8 shows a side view of the bellows shown in Figure 7;

Figure 9 shows a cross section view of the bellows shown in Figure 7; Figure 10 shows a perspective view of a clip ring of the fitting shown in Figure 1;

Figure 11 shows a cross section view of the ring shown in Figure 10;

Figure 12 shows a plan view of the ring shown in Figure 10;

Figure 13 shows a perspective view of a cap of the fitting shown in Figure 1;

Figure 14 shows a cross section view of the cap shown in Figure 12; Figure 15 shows an underside view of the cap shown in Figure 12;

Figure 16 shows a cross section view of an inner cap of the fitting shown in Figure

i ;

Figure 17 shows a side view of a seal of the fitting shown in Figure 1;

Figure 18 shows a plan view of the seal shown in Figure 16; and Figure 19 shows a cross section view of the seal shown in Figure 17 taken through the line A- A.

Referring to the drawings the tap fitting 1 comprises a body 3 made from brass having a bore 5 formed through its centre along the body's longitudinal axis. The bore 5 becomes progressively narrower toward one open end 7 where it terminates with a tapered inner wall 9 which is substantially frustoconical in shape. Two apertures 11, 12 are formed through the sidewall of the body 3 on opposite sides respectively of the body 3 at the narrower end 7. Thus fluid can flow through the two apertures 11, 12 and narrower bore end 7 of the body.

The bore 5 of the body 3 is sized and configured to receive a brass spindle 13 which is moveable relative to the body 3 and which has a first flange 15 at one end. A second flange 17 of substantially the same diameter as the first flange 15 projects from the spindle 13 sidewalls a short distance from the first flange 15. The distance of separation between the first and second flanges is chosen to be sufficient to accommodate an O-ring 19 made from nitrile material with a snug fit. The side 21 of the second flange facing away from the first flange 15 is tapered so that the spindle 13 can be arranged relative to the tapered inner wall 9 of the body to form a channel between the spindle and the body. The diameter of the two flanges 15, 17 is chosen to be slightly less than the narrowest part of the bore 5 so that the spindle 13 can pass through the bore 5. The thickness of the O-ring 19 is chosen so that, when mounted to the spindle 13, the O-ring 19 abuts the tapered inner wall of the body 3 if the spindle 13 is urged in a direction toward the narrow opening, thereby restricting the spindle 13 from travelling further into the bore 5 and closing any channel formed between the second flange 17 and the tapered inner wall 9 of the body 3.

A channel or capillary tube 23 is formed in the other end of the spindle 13 and extends a short distance along the longitudinal axis of the spindle through its centre. The channel 23 comprises two substantially cylindrical sections 25, 27, one section 27 being smaller in diameter than the other section 25. A shoulder 29 is formed at the interface between the two cylindrical sections to form an abutment for a screw head. The channel 23 further comprises a constricted section 31 that opens into a substantially horizontal aperture 33 that extends through the spindle 13 from one side to the other. The channel 23 therefore forms a pathway for the flow of air from one end of the spindle 13 through the sidewall of the spindle. The channel 23 accommodates a suitably shaped brass screw 35 and the inner wall of the cylindrical sections 25, 27 of the channel 23 comprises a screw thread to permit the screw 35 to engage with the channel 23. The screw 35 comprises a nose portion 37 which is shaped to fit within the constricted section 31 of the channel 23. The position of the screw 35 within the channel 23 can be adjusted to control the size of the air pathway through the spindle 13 between the screw 35 and the channel 23.

The fitting 1 further comprises a top hat shaped connector 39 made from polyoxymethylene which is removably attached to the narrower end 7 of the body 3 with a friction fit. The top hat connector 39 comprises a substantially cylindrical hollow centre which is open at one end and closed at the other. The closed end comprises an aperture 41 formed therethrough to create a fluid flow path through the connector 39 from one end to the other. The diameter of the hollow centre is chosen to accommodate the flange end of the spindle 13 and is large enough such that when the flange end of the spindle is inserted into the connector 39, the sides of the flange are spaced from the sides of the connector so that fluid can flow therebetween, even when the O-ring 19 is seated between the first 15 and second 17 flanges. The part of the hollow centre adjacent the closed end comprises a narrower diameter section 43 which is dimensioned such that when the spindle is fully inserted into the connector, the bottom of the spindle abuts the closed end of the connector, closing off the aperture 41 and the O-ring 19 forms a seal between the spindle 13 and the inner walls of the narrower diameter section 43. The top hat connector 39 may be replaced with other similarly shaped top hat connectors with different sized apertures to vary the volume of the fluid flow path through the connector 39 and into the body 3.

The spindle 13 further comprises a third flange 45 which projects from the spindle body about a third of the way along the body from the first and second flange end. A shallow recess 47 is formed at the interface between the bore 5 and the two body apertures 11, 12 and is arranged to face the third flange 45 of the spindle 13 when the spindle is seated within the body 3. A stainless steel coil spring 49 is arranged around the spindle 13 between the third flange 45 and the walls of the recess 47 so that the spindle is 13 biased away from the recess 47. A resilient silicone rubber bellows 51 having a through aperture 53 and flanged end 55 is arranged around the spindle 13. The bellows 51 is arranged such that its flanged end 55 is nearest the channel end ofthe spindle 13 and such that the opposite end extends around and is captured by the third flange 45 of the spindle 13. The fitting body 3 comprises a shoulder portion 57 toward the fatter end of the body against which the flanged end 55 of the bellows 51 may sit when the spindle 13 is inserted into the body 3. A substantially circular ring 59 made from polyoxymethylene having six substantially equally spaced castellations 61 arranged around an upper surface of the ring 59 is removeably mounted on the body 3 on top of the flanged end 55 of the bellows 51 to trap the bellows between the third flange 45 and the ring 59. The ring 59 is held in place by a small lip 63 that projects from the outer wall of each castellation 61 and engages with a corresponding groove in the body 3. The castellations 61 are provided to enable the ring to flex slightly so that the ring 59 can be urged into the body without breaking. If the spindle 13 is moved into the body 3, the flanged end 55 of the bellows 51 is held in place by the ring 59 and the other end of the bellows 51 is pulled with the spindle 13 by the third flange 45 away from the flanged end 55, thereby stretching the bellows 51. The bellows 51 is arranged such that, when the spindle 13 is inserted into the body 3, the bellows 51 forms a barrier so that fluid cannot pass from one side of the bellows 51 to the other between the body 3 and the spindle 13. The fitting 1 further comprises an inner cap 70 which is substantially cylindrical in shape and which has an open end 72 and a closed end 74. The cap 70 is dimensioned to sit on top of and extend around the fattest part of the body 3 with a relatively tight fit but is moveable relative to the body 3. An aperture 76 is formed in the closed end of the inner cap and comprises a collar 78 which engages with a corresponding formation on the spindle 13. An outer cap 80 having a smooth curved outer surface is provided which is dimensioned to extend around the inner cap 70 with a narrow gap 82 therebetween. The narrow gap 82 opens out to the external environment at the open ends 84 of the two caps 70, 80. The upper face of the outer cap 80 comprises an aperture 86 which is positioned such that when the outer cap 80 is connected to the inner cap 70, the apertures 76, 86 of the inner 70 and outer 80 caps are substantially aligned so that the channel 23 formed in the end of the spindle 13 can be accessed via the two apertures 76, 86 from outside the fitting 1.

The outer cap 80 further comprises a substantially cylindrical recess 88 formed in the upper face around the aperture 86. A cover 90 which is dimensioned to fit within the recess 88 is provided to close off the aperture 86 and prevent unauthorised access to the spindle 13. The sidewalls 92 of the recess 88 are tapered in toward the upper surface so that when the cover 90 is seated in the recess 88 it is held in place by the tapered wall 92. The cover 90 can optionally be provided in red or blue to denote whether or not the fitting is for dispensing hot or cold water. A stainless steel half nut 94 is arranged between the cover 90 and a shoulder 96 formed by the recess 88 to engage with an end of the spindle 13 so that the spindle is fixed relative to the inner and outer caps. Three equally spaced holes 98 are formed in the recess 88 and extend through to the narrow gap 82 formed between the inner cap 70 and outer cap 80. A seal 100 is arranged between the outer wall of the body 3 and the inner wall of the inner cap 70. The seal 100 comprises a substantially cylindrical section 102 and a flared section 104 which is substantially frustoconical in shape. The flared section extends from the body 3 to the inner cap 70 and is directed such that it extends toward the open end 72 of the inner cap 70. The seal material comprises a bifunctional perfluoropoly ether which gives the seal 100 a low coefficient of friction, improved wear and abrasion resistance and better chemical resistance. The seal 100 is fixed relative to the body 30 so that when the inner cap 70 is urged toward the body 3, the cap 70 moves relative to the seal 100. The flared section 104 restricts the flow of air from the chamber outside the fitting via the interface between the seal 100 and the inner cap even whilst the cap 70 is moved relative to the body 3.

The seal 100, inner cap 70, body 3 and region 106 between the bellows 51 and the spindle 13 together define a space or chamber 108 which is accessible from outside the fitting 1 via the air channel 23 formed in the spindle 13. Thus, when the screw 37 in the air channel 23 is fully seated within the channel, air cannot flow into or out from the chamber 108. The flow path through the channel 23 can be adjusted by adjusting the relative position of the screw 37 within the channel 23 thereby to open up the channel by varying amounts. The chamber 108 is linked to air outside of the fitting 1 via the channel 23 in the spindle, the three holes 98 formed in the outer cap 80 and the narrow gap 82 between the caps 70, 80. The outer wall of the body 3 comprises a screw thread 110 to enable the fitting 1 to be connected to a tap faucet body so that a complete tap fitting can be assembled. An outer O-ring 112 is arranged above the screw thread 110 around a part of the body 3 to form a seal between the fitting 1 and tap faucet body. To install the fitting 1, the appropriate top hat connector 39 is chosen depending on the desired tap flow rate for the tap which dictates the size of the aperture 41 required in the connector 39. The top hat connector 39 is attached to the narrow end 7 of the body 3 and the assembled fitting 1 is inserted top hat connector first into a tap faucet body having an outlet and screwed in place. The body 3 is arranged relative to the faucet body such that when it is installed and the fitting is urged to an open configuration, a fluid flow path is formed between the faucet body and faucet outlet via the bore 5 of the fitting 1. When the fitting 1 is seated in place, the spindle 13 and caps 70, 80 are urged by the spring 49 toward a closed position in which the spindle O-ring 19 is seated against the tapered inner end wall 9 of the bore 5. When in this position, water is restricted from passing through the faucet body and through the bore to the faucet outlet.

The fitting 1 can be moved to an open position by pushing the caps 70, 80 toward the body 3 which moves the spindle 13 toward the closed end of the top hat connector 39 thereby moving the O-ring 19 away from the bore 5 and opening up a fluid pathway through the bore 5 between the spindle 13 and the body 3. When the caps 70, 80 are depressed water can flow through the aperture in the top hat 39, through the bore 5 and apertures 11, 12 and out from the faucet outlet. If the caps 70, 80 are fully depressed and the spindle 13 is fully seated within the top hat connector 13, the spindle closes off the top hat connector aperture 41 so that water cannot flow through the fitting 1. This ensures that the push tap cannot be held down for continuous flow by, for example, vandals. The fitting 1 operates on an air based system in which movement of the spindle 13 relative to the body 3 from a closed position to an open position stretches the bellows 51 as described above thereby urging air out from the chamber 108 through the air channel 23 in the spindle 13. The flow of air out from the chamber 108 creates a vacuum within the chamber. Releasing the caps allows the spring 49 to urge the caps and spindle back toward the closed position which draws air back into the chamber via the narrow gap 82 and channel 23. By adjusting the position of the screw 35 within the channel 23, it is possible to adjust the rate at which air may flow back into the chamber 108 and therefore adjust the speed at which the caps 70, 80 and spindle 13 return to the closed position. Therefore, the fitting can be arranged to move from the open position to a closed position for different lengths of time depending upon the size of the air pathway between the channel and the screw. Thus, it is possible to adjust the time over which water will flow through the tap fitting and hence the volume of water that is dispensed. In this embodiment the flow time can be adjusted from 0 seconds (screw closed position) to 20 seconds (screw fully open position). It is envisaged that the flow time could be increased to 90 seconds by adjusting the size of the chamber or the length of the channel.

If it is desired to change the flow rate, the fitting is removed from the faucet and the top hat connector is replaced with a different top hat connector comprising a different diameter aperture. If it is desired to adjust the flow time, the cover is removed from the recess and a screw driver is used to turn the screw within the channel to adjust the size of the flow path and, hence, the time it takes for the chamber to refill with air after the caps are depressed and released. The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.