IE20140242A1 - A control device for a water mixer assembly - Google Patents

Abstract

A control device (30) for a mixer assembly in which hot and cold water flows are mixed to regulate the water temperature at an outlet, the control device (30) having a moveable temperature selector by which a user may adjust the outlet water temperature and a mixer element operatively connected to the temperature selector and by which the relative amounts of hot and cold water in a mixing chamber are varied in response to movement of the temperature selector, and an adjustable transmission mechanism (40, 41, 42) operatively disposed between the temperature selector and the mixer element.

Description

Title: A Control Device Technical Fieid of the Invention This invention relates, in broad terms, to tbe field of water mixer assemblies, in which hot and cold water flows are mixed to regulate the water temperature at an outlet. For the avoidance of doubt, "hot" and "cold" are used herein as relative terms, in that "hot" water refers to water which has been heated to some extent, and "cold" water relates to water which has not been heated - or which has been heated to a lesser extent.

Such mixer assemblies are commonly found in ablutionary installations such as showers and baths, and thus the invention relates more specifically, but not exclusively, to a control device for the regulation of outlet water temperatures in domestic mixer shower installations.

Background to the Invention and Overview of the Prior Art Domestic shower installations are available in a variety of types.

In very broad terms, domestic showers can be categorised either as electric, or mixer types.

Electric showers use electrical power to energise a heater can which, using electrical heating elements, heats water as it passes through the can, with electronic circuitry and sensors typically being used to regulate the output temperature. Usually, the outlet temperature is changed by varying the flow of the incoming (cold) water through the can, so that the water stays in contact with the heating element(s) for a longer, or shorter period of time. On some models, it is also possible to increase/decrease the power to the heater can, :ombifiations of electrical heating elements.

IE 14 0 24 2 Mixer showers, which typically are found in domestic installations where a ready supply of heated water (e.g. from a central heating system) is available, operate on a somewhat simpler basis, by combining an incoming hot water feed with a cold (mains) feed, with the relative amounts of hot/cold water being varied, so as to provide a desired outlet temperature.

Many showers are provided with a thermostatic mixing valve, so that variations in the temperature/pressure of the incoming hot water feed can be compensated for, so as to maintain a desired outlet temperature. Such thermostatic showers are often installed in dwellings/bathrooms used by children or people with reduced physical, sensory or mental capabilities (or a lack of experience/knowledge of showering) so that a safe, maintained maximum temperature can be set, thus minimising the risk of injury or discomfort to the user.

Thermostatic instantaneous electric showers which incorporate electronic circuitry and control systems generally have a way of selecting the maximum possible temperature on an internal PCB (printed circuit board), so that an external temperature control knob (or dial) can be used over the full travel (usually rotational) of the knob, irrespective of the maximum temperature which has been selected during manufacture or installation. Thus, the internal electronics enable a user to operate the knob "fully", despite the fact that an upper temperature limit has been pre-set.

However, where mechanical thermostatic instantaneous electric showers are involved (where a substantially constant flow and temperature of hot water is blended with a variable flow of cold water), it is necessary for the mixer valve to be physically prevented from allowing too little cold feed to enter it (thus exceeding a specific outlet temperature), with this being done by the use of it 1 4 024 2 mechanical stops which interact with the manually-operable temperature control knob.

Where a relatively low maximum temperature needs to be set (during 5 installation, by a trained installer), problems can arise because the stop will prevent the temperature control knob from being moved to its perceived maximum temperature position. This can give users the impression of a malfunction (in that the control knob appears to have stuck), leading to possible damage if a user tries to force the knob beyond the maximum permitted position.

In addition, because many showers offer a variety of installer-set maximum temperatures, simply changing the relative positions of the temperature control knob and the control spindle of the mixer valve assembly (so that the "maximum temperature" position of the knob corresponds to the required maximum temperature of the outlet water) does not satisfactorily address the issue. This is because this simple re-positioning has the effect of increasing the water temperatures throughout the range of movement of the temperature control knob, leading to an outlet water temperature which is too high (and noticeably so), when the "minimum temperature" position is selected.

Summary of the Invention In accordance with a first aspect of the present invention, there is provided a control device for a mixer assembly in which hot and cold water flows are mixed to regulate the water temperature at an outlet, the control device having a moveable temperature selector by which a user may adjust the outlet water temperature and a mixer element operatively connected to the temperature selector and by which the relative amounts of hot and cold water in a mixing chamber are varied in response to movement of the temperature selector, and IE 14 0 2 4 2 an adjustable transmission mechanism operatively disposed between the temperature selector and the mixer element.

The transmission mechanism may enable the extent of variation which occurs 5 in the mixing chamber in response to a given amount of movement of fhe temperature selector, to be adjusted.

The temperature selector may be moveable between minimum and maximum temperature positions, with the transmission mechanism enabling the maximum water temperature at the outlet to be adjusted, without affecting the maximum temperature position of the selector.

The temperature selector may be angularly moveable between the minimum and maximum temperature positions, with the transmission mechanism having an input shaft on or operatively associated with the selector.

The transmission mechanism may have an output shaft on or operatively associated with the mixer element.

The input and output shafts may be operatively connected by a gear arrangement.

The gear arrangement may have at least two modes of operation, so that different gear ratios between the input and output shafts may be selected.

In a first mode of operation, a first set of gears may be engaged, with a second set of gears being engaged in the second mode of operation.

The transmission mechanism may comprise a switch having first and second 30 positions corresponding to the first and second modes of operation of the gear arrangement.

IE 14 024 2 Movement of the switch between the first and second positions may disengage a driving gear wheel from a first driven gear wheel, and engage it with a second driven gear wheel.

The switch may comprise a cam surface whereby angular or translational movement of the switch effects said disengagement.

The cam surface may engage with a cam follower associated with the driving 10 gear wheel, so that movement of the switch effects movement of the gear wheel substantially along its axis of rotation.

The switch may comprise securing means to secure it in at least one of the two positions.

The mixer assembly may be a shower mixer valve assembly.

In accordance with a second aspect of the present invention, there is provided a mixer shower comprising a control device substantially in accordance with one or more features of the first aspect of the invention.

Detailed Description of the Invention and Preferred Embodiments Preferred and non-limiting embodiments of the various aspects of the present 25 invention will now be described in greater detail, but strictly by way of example only, by reference to the accompanying drawings, of which: Figure 1 is a schematic view, in plan, of a prior art thermostatic instantaneous electric shower; IE 1 4 ο 2 4 2 Figure 2 is a plan view showing the key elements of the control device of the present invention, with the maximum outlet temperature set to 41 °C; Figure 3 shows the control device of Figure 2, with the maximum outlet 5 temperature set to 43°C; Figure 3A shows the same arrangement as Figure 3, but with a temperature control knob adaptor also being shown; Figure 4 shows the control device of Figures 2 and 3, with the maximum outlet water temperature set at 47°C; Figure 5 shows, in schematic form (and in perspective view) the key inner workings of the control device of Figures 2, 3 and 4, with the switch in a first position; Figure 6 is a close-up view of certain elements shown in Figure 5; and Figure 7 is a close-up view of the components of Figures 5 and 6, but with the 20 switch in a second position.

Referring first to Figure 1, there is shown at 10 a schematic illustration of the main components of a known (prior art) thermostatic instantaneous electric mixer shower.

The shower comprises an outer housing (part of which is shown at 11), within which are contained the key components of the shower assembly. Cold, i.e. unheated/mains water enters the assembly at an inlet 12, passing through to the internal components via an electrically-operated solenoid valve 13 which, when closed, is effective to prevent water from flowing to the other elements of the shower. The incoming cold water feed (once the solenoid valve 13 has IE 140242 been opened) then passes to a flow switch 14 which senses the incoming water flow and, via a PCB (printed circuit board), energises an electrical contact, which powers the rest of the shower’s components. The flow switch is thus effective to prevent any power from being supplied to the heater can 15, so that any potentially-dangerous overheating does not occur. In generally conventional manner, the heater can 15 includes one or more electrical heating elements which are energised to heat the incoming water. These elements are not illustrated in the drawing, for reasons of clarity. In conjunction with a printed circuit board 16, a thermal safety cut-out 17 ensures that if a specific temperature should be exceeded, then power to the heater can 15 can rapidly be disconnected. The heater can 15 is also provided with a pressure relief device (PRD) 18 which will open in the event of an excessive build up of pressure, within the heater can housing.

Regulation of the outlet water temperature (at the outlet 19) is effected by varying the relative amounts of heated water (from the heater can 15) and cold water, which, taken from a separate feed from the inlet 12, are combined in a mixing chamber (not shown) which forms part of a temperature control device 20. The mixing chamber - in conventional manner - is provided with a thermostat - in this case, in the form of a wax capsule. This mitigates against (i.e. compensates for) changes in the temperature and/or pressure of the incoming hot water feed.

In generally conventional manner, the temperature control device 20 comprises a central rotatable spindle 21, to which (in use) is attached an externally-accessible temperature control knob (or lever/dial, not shown in this figure) which a user can manipulate using rotational movement to select a desired water outlet temperature. The temperature control knob can be directly connected to the spindle, or an intermediate component (such as an adaptor) can be used, depending on the design of the shower, and its housing.

IE 1 4 0 2 4 2 The spindle 21 is integral with (or connected to) a mixer valve stem (also not shown) which, when undergoing rotational movement, selectively opens/closes a water inlet channel, thus varying the amount of cold (or, optionally, hot) water, which flows into a mixing chamber, just beneath the upper surface of the temperature control device. Evidently, when the incoming cold water feed is completely shut off (to the mixing chamber) or when it adopts a minimum cold flow configuration, the proportion of hot water in the mixing chamber will be at its highest, leading to a maximum outlet water temperature, at the outlet 19. In this particular configuration, the hot water exiting the heater can 15 is maintained at a substantially constant temperature (about 55°C) so that simple variation of the cold water flow into the mixing chamber is sufficient to vary (with a considerable degree of accuracy and control) the temperature of the hot/cold water mix, leaving the shower at the outlet 19.

The mixer valve stem, which is operatively connected to the spindle 21, is moved as a result of rotation of the temperature control knob attached to the front of the shower casing. Thus, the extent to which the temperature knob can be rotated (typically clockwise, in order to increase the outlet temperature) has a direct effect on the maximum outlet water temperature which the shower is able to provide.

For this reason, it is known in the prior art for such shower assemblies to be pre-settable with a maximum safe (permitted) outlet temperature. This is done by physically preventing movement of the external temperature control knob beyond a certain point, in its rotational path of movement.

In the example shown in Figure 1, this is achieved using a simple barrier or stop 22 which abuts (i.e. gets in the way of) a protrusion which extends downwardly from the underside of the temperature control knob, so that once IE 1 4 0 2 4 2 the protrusion and stop engage one another, continued movement of the knob is not permitted.

In consequence, the angular position at which the stop is disposed has a direct 5 effect on the extent of permitted rotation of the temperature control knob, and thus has a direct effect on the maximum permitted outlet water temperature.

In order to adjust the maximum permitted outlet water temperature, an engineer (during installation of the device) is able to release a maximum temperature ring 23 (via removal of a screw 24), and rotate the ring about the axis of the spindle 21, until the stop 22 lies at an appropriate position, corresponding to a desired maximum outlet temperature.

Once the desired angular position has been arrived at, the screw 24 is replaced, through one of the available apertures 25, meaning that, once the shower cover and temperature control knob are replaced, the temperature control knob will not be able to travel (rotatronally) past the position at which its protrusion engages with the stop 22.

In so-called "care" environments, in which the electric shower can be used by children, or by people with reduced physical, sensory or mental capabilities, it is known for a number of relatively low maximum outlet water temperatures to be available, for pre-setting by an installer.

In the UK, the BEAB (British Electrotechnical Approval Board) specifies a maximum outlet water temperature of 41 °C in such environments, and whilst this maximum temperature is thus available (via adjustment of the temperature ring 23), thermostatic showers of this type are also adjustable (by an installer) so as to provide a wider temperature range, typically between 35°C and 47°C.

In this example, which is standard for this type of shower (in the UK) the unit is pre-set (i.e. factory set) with a maximum outlet temperature of 47°C, meaning IE 1 4 024 2 that the full extent of rotation (typically a travel of about 300°) of the temperature control knob is effective to vary the outlet temperature between 35°C and 47°C - i.e. 25° of rotation, for each degree of temperature change.

When the shower is adjusted (by an installer) so as to set a maximum outlet temperature of 41 °C (for example), this has the effect of preventing angular movement of the temperature control knob beyond the "midnight" position, given that only half of the full extent of rotational travel is needed, in order for the 41 °C maximum temperature to be reached. This is not only troubling from an engineering perspective, but also gives rise to the possibility of breakage, as a user may try to force the temperature control knob beyond its maximum, in the mistaken belief that a component has got "stuck" in the housing.

The remainder of the figures (and the associated description) illustrate how the present invention addresses these shortcomings, by way of a revised and improved configuration of temperature control device.

Referring next to Figure 2, a revised form of temperature control device 30 (in accordance with the present invention) is shown. At a high level, the function of the temperature control device 30 is similar to that of the device 20 shown in Figure 1, although it now comprises two rotatable spindles in the form of an input shaft 31 which, in use, is co-axial with (and driven by movement of) an external temperature control knob, and an output shaft 32 (see also Figure 5) which is directly attached to or operatively associated with a valve stem, within a (generally conventional) mixing chamber, disposed beneath the upper surface 33 of the control device. For reasons of clarity, not all of the various components of Figure 1 are repeated in Figure 2, although a flow switch 14 and solenoid valve 13 are illustrated, in substantially corresponding positions. Specifically, in Figure 2, the flow switch 14 is in the form of a flow meter, which is able to provide more detailed flow information to the shower’s electronic circuitry.

IE 1 4 0 242 The temperature control device 30 has an exit channel 34 which is connected (although not shown) to the water outlet 19 of Figure 1, by way of suitable plumbing/elbow connections, in generally conventional manner.

In view of the offset nature of the input and output shafts 31 and 32, a transmission mechanism is provided, between them. As can be seen from Figure 5 in particular, the transmission mechanism is in the form of a gear arrangement, featuring a number of selectively inter-engageable gear wheels.

As explained in more detail, by reference also to Figures 5, 6 and 7, a switch 35 is provided, which is moveable (see Figures 2, 3 and 4) between two positions, marked A and B. In brief, movement of the switch between positions A and B changes the gear wheel engagements between the input and output shafts 31 and 32, thus effectively altering the gear ratio, between the two shafts. In consequence, the extent of angular movement (i.e. rotation) undergone by the output shaft 32, in response to a given amount of angular (rotational) movement of the input shaft 31 can be altered, by way of the different gear selections.

Figure 2 shows the temperature control device in an installer-set position in which the maximum outlet water temperature is 41 °C. This corresponds to the UK "BEAB" standard for "care" installations, as the relatively low maximum outlet temperature effectively removes any possibility of scalding/injury to an impaired or inexperienced user. The input shaft 31 has a splined outer configuration 36 which engages (not shown) with a corresponding configuration beneath a temperature control knob, which is operatively connected to it, through an aperture in the external housing of the shower. As explained below, this operative connection can be via an intermediary such as a control knob adaptor.

IE 1 4 0 2 4 2 The operative connection means that rotation of the temperature control knob will cause the input shaft 31 to rotate and, in turn, cause the output shaft 32 (which is connected to the mixing chamber therebeneath) to rotate, thus altering the relative quantities of hot and cold water, in the mixing chamber.

A non-removable stop 37 is disposed towards the base of an outer ring 38 surrounding the input shaft 31, with the stop 37 acting as a barrier to unimpeded rotation of the temperature control knob. For the avoidance of doubt, the outer ring 38 forms part of the housing surrounding the input shaft 31 and does not rotate with it. In other words, the stop 37 (by contact with the control knob adaptor - see below) defines the limits of rotational travel of the control knob, which, in practice, corresponds to the minimum and maximum temperature settings, as shown on the outside of the shower housing, and which are visible to a user.

In order to change the maximum outlet temperature to 43°, an installer needs simply to detach the external temperature control knob (by removal of the front casing of the shower) and the control knob adaptor, and rotate (manually, and clockwise) the input shaft 31, causing the output shaft to rotate (also clockwise) until the indicator arrow 39 points towards the "43° symbol. The temperature control knob is typically attached to the front of the shower’s casing in such a way that it can rotate (or at least move angularly) in relation to it, but cannot be removed from the front casing. Thus a clip may be provided (during manufacture) on the inside of the front casing, to stop the temperature control knob from becoming detached.

The installer then needs to replace the control knob adaptor (shown in Figure 3A) on the splined input shaft, attaching the control knob, in turn, to the adaptor, by replacement of the front casing. Before the casing is replaced, the temperature control knob is moved to its "maximum temperature" position. The adaptor is disposed at an angular position which corresponds with the IE 1 4 0 24 2 maximum temperature setting (i.e. fuii clockwise rotation), and the control knob also conveys a ‘maximum temperature’ indication, by virtue of the external markings on the outside of the shower housing.

Figure 3A shows the components of Figure 3 (and the same configuration) but with the addition of the temperature control knob adaptor 60. The adaptor 60, formed (in this example) as a one-piece plastics moulding, has an internally splined configuration (not shown) which mates with the external splines of the input shaft 31. This means that rotation of one causes rotation of the other.

The adaptor 60 has a stop 61 extending from its lower periphery 62, with the stop 61 abutting the stop 37 on the outer ring 38. This abutment of the two stops 37 and 61 limits the extent of angular movement that the adaptor 60 is able to undergo, and thus (when the adaptor is in place) the extent of angular movement that the input shaft 31 is able to undergo.

The upper section of the adaptor 60 has a recess 63 which, in this example, is wedge-shaped. The recess 63 mates (in only one possible way) with a corresponding protrusion or extenson, on the underside of the temperature control knob (not shown). This means that once the adaptor 60 has been attached to the input shaft 31 at a position corresponding to a maximum temperature, the control knob (not shown) can only be attached to the adaptor in one way, meaning that the control knob must be attached in such a way that a maximum temperature setting is indicated, to a user.

It will be understood that other shapes of recess (e.g. keyhole or a triangle having only two sides of equal length) are also envisaged, as are alternative forms of engagement between the adaptor and control knob.

For reasons of clarity, the adaptor 60 is not shown in the other drawings.

IE 1 4 024 2 This adjustment of the output shaft will thus have had the effect of altering the position of the internal mixing valve stem (which controls the supply of cold water to the mixing chamber), so that less cold water is supplied, with the output shaft in that position.

Because the degree of permitted angular movement of the input shaft (and thus the externally-operable temperature control knob) has not been affected, the full extent of angular (rotational) travel remains possible, insofar as a user is concerned. As the maximum outlet temperature has only been increased by 2°C (see Figure 3), this means that the minimum water temperature (corresponding to the minimum perceived setting on the external surface of the shower housing) will also only have increased by 2°C. Research by the applicants has shown that a change of this nature, in a relatively low temperature range (i.e. 35°C to 37°C) is rarely perceived by a user and thus an alteration of the gearing, between the input and output shafts 31/32 is not required for such an adjustment. In other words, most users will not notice the change at the lower end of the temperature range.

Figure 4 shows the temperature control device 30 in a configuration in which the maximum outlet water temperature has been increased substantially, to 47°C. In the figure, the switch 35 remains at position B meaning that, if the temperature control knob were simply replaced, and operated in the normal manner, the temperature range would extend only between 41 °C and 47°C, with 41 °C being far too high for a user to be able to enjoy what is perceived as a "cool shower. In other words, using the same gear arrangement as in Figures 2 and 3 does not enable the outlet water temperature to be reduced to a sufficient extent, because of the limit on the angular (rotational) travel of the input shaft 31 and the temperature control knob to which it is attached.

IE 1 4 0242 In order to increase the angular displacement of the output shaft, without affecting the required angular movement of the input shaft, a different gear arrangement, between the input and output shafts, is needed.

This is achieved by movement of the switch 35 from position B to position A, as shown schematically in Figure 4.

Figure 5, which shows the key internal components of the temperature control device 30 of Figures 2, 3 and 4, shows how movement of the switch from position B to position A alters the gearing, between the input and output shafts 31/32.

In the configuration of Figure 5, in which the switch 35 is in position B, a first (driving) gear wheel 40, co-axial and rotatable with the input shaft 31, meshes with an intermediate (driven) gear wheel 41, which, in turn, engages with an ultimate (driven) gear wheel 42 which is attached to the output shaft 32. The effect of this is that clockwise rotation of the input shaft 31 induces clockwise rotation of the output shaft 32, with the relative extents of their angular rotation being governed by the gear ratio which exists between them.

As shown more clearly in Figure 6, the switch 35 has a cam 50, provided with a cam surface 51 which engages with a cam follower 52 in the form of a peg which extends downwardly from a plate 52a which sits beneath (but does not rotate with) the driving gearwheel 40. Thus the peg is able only to undergo up and down (reciprocating) movement, while the driving gear wheel 40 can rotate, above it. In this example, multiple cam surfaces and followers are provided, at approximately equal angular positions, around the axis of rotation of the input shaft 31, but it will be appreciated that alternative configurations are also possible, and envisaged. However, what will also be appreciated is that the engagement of the cam surface 51 with the cam follower 52 is IE 1 4 0 2 4 2 effective to bias the driving gear wheel 40 in a generally upwards direction, keeping it in meshed engagement with the intermediate driven gearwheel 41.

In this embodiment, a small abutment 53 is provided, to hinder/prevent 5 accidental movement of the switch 35 between positions A and B, with movement between the positions requiring the switch to be pushed (manually) up and over the abutment. As an alternative, securing means could be provided (such as threaded or self-tapping fasteners) to hold the switch in the desired position.

As shown in Figure 7, movement of the switch 35 from position B to position A allows the driving gear wheel 40 to move downwardly, under the action (in use) of a coil spring 54, such that the driving gear wheel 40 becomes disengaged from the first driven gear wheel 41.

It will be understood, of course, that the terms ‘above’, ‘below’, ‘upwardly’, and ‘downwardly’ are used here in a relative sense. When the shower unit is installed, and in use, the unit will generally adopt a vertical configuration on a wall, meaning that (for example) the peg 52 and driving gear wheel 40 will undergo translational movement in a substantially horizontal plane towards and away from the wall.

Instead, the driving gearwheel 40 becomes engaged with (i.e. meshes with) a second driven gear wheel 55, which itself meshes with (i.e. drives) the ultimate driven wheel 42, and thus the output shaft 32.

The relative sizes of the gear wheels 40, 41, 55 and 42, mean that a different effective gear ratio is adopted, between the input and output shafts 31/32.

This, in turn, means (by careful selection of the various gear wheel sizes) that a "complete" angular sweep of the externally-accessible temperature control IE 1 4 0 242 knob can be made to equate to a full (i.e. corresponding to a temperature change of 12°C) movement of the output shaft, meaning that when a user turns the externally-accessible temperature control knob to its perceived minimum setting, the outlet water temperature will be reduced to 35°C, as opposed to only 41 °C, had the switch not been moved from position B to position A.

It will be appreciated that this adjustable transmission mechanism (in the form of the selectable gear arrangements) provides a significant improvement over known configurations, in that a substantially "full" extent of movement of the user-accessible temperature control knob remains possible, irrespective of the installer-set maximum permitted temperature.

In the specific embodiments shown, only two alternative gear settings are illustrated, but it will be understood by those skilled in the art that (space constraints permitting) there is no limit to the number of alternative gear arrangements and configurations which could be provided.

When used in this specification and claims, the terms comprises and comprising and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (19)

Claims

1. A control device for a mixer assembly in which hot and cold water flows are mixed to regulate the water temperature at an outlet, the control device 5 having a moveable temperature selector by which a user may adjust the outlet water temperature and a mixer element operatively connected to the temperature selector and by which the relative amounts of hot and cold water in a mixing chamber are varied in response to movement of the temperature selector, and an adjustable transmission mechanism operatively disposed 10 between the temperature selector and the mixer element.

2. A control device according to claim 1 wherein the transmission mechanism enables the extent of variation which occurs in the mixing chamber in response to a given amount of movement of the temperature selector, to be 15 adjusted.

3. A control device according to claim 1 or 2 wherein the temperature selector is moveable between minimum and maximum temperature positions, with the transmission mechanism enabling the maximum water temperature at 20 the outlet to be adjusted, without affecting the maximum temperature position of the selector.

4. A control device according to any preceding claim wherein the temperature selector is angularly moveable between the minimum and 25 maximum temperature positions, with the transmission mechanism having an input shaft on or operatively associated with the selector.

5. A control device according to any preceding claim wherein the transmission mechanism has an output shaft on or operatively associated with 30 the mixer element. IE 1 4 0 24 2

6. A control device according to claim 5 wherein the input and output shafts are operatively connected by a gear arrangement.

7. A control device according to claim 6 wherein the gear arrangement has 5 at least two modes of operation, so that different gear ratios between the input and output shafts may be selected.

8. A control device according to claim 7 wherein in a first mode of operation, a first set of gears is engaged, with a second set of gears being 10 engaged in the second mode of operation.

9. A control device according to claim 7 or 8 wherein the transmission mechanism comprises a switch having first and second positions corresponding to the first and second modes of operation of the gear 15 arrangement.

10. A control device according to claim 9 wherein movement of the switch between the first and second positions disengages a driving gear wheel from a first driven gear wheel, and engages it with a second driven gear wheel.

11. A control device according to claim 10 wherein the switch comprises a cam surface whereby angular or translational movement of the switch effects said disengagement. 25

12. A control device according to claim 11 wherein the cam surface engages with a cam follower associated with the driving gear wheel, so that movement of the switch effects movement of the gear wheel substantially along its axis of rotation. 30

13. A control device according to any of claims 9 to 12 wherein the switch comprises securing means to secure it in at least one of the two positions. IE 1 4 0 2 4 2

14. A control device according to any preceding claim wherein the mixer assembly is a shower mixer valve assembly.

15. A control device according to any preceding claim wherein the mixer 5 assembly is a thermostatic instantaneous electric mixer valve assembly.

16. A control device substantially as hereinbefore described and/or as shown in the accompanying drawings. 10

17. A mixer shower comprising a control device substantially in accordance with any one of the preceding claims.

18. A thermostatic instantaneous electric mixer shower comprising a control device substantially in accordance with any one of the preceding claims.

19. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.