GB2351548A - Rotary control knob with an overridable stop - Google Patents

Abstract

A control has a rotatable control knob 2 using an overridable stop 14 on cam surface 10 of control base 6 for preventing rotation of the control knob in only one direction of rotation. Release button 4 releases the engagement of a member 18 with the overridable stop and is movable from a first position (Fig 2) proud of an outer surface of the control to a second position (Fig 1) generally flush with the outer surface so as to release the overridable stop. The release button is arranged to move from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop and the engaging member may be provided on an extension 22 of the release button at a diametrically opposite side of the knob to the release button. In alternative arrangements, the cam is on the knob and the button on the control base 6, or the button and the engaging member 18 may be on the same side of the knob (Figs 9-12). The position of the stop may be adjustable. The control may be used for a hot and cold water mixing valve to overridably prevent the delivery of very hot water.

Description

2351548 CONTROL The present invention relates to a control, in particular

a control having a rotatable control knob, for instance for use with a fluid control valve.

It is known to provide a valve for mixing supplies of hot and cold water so as to provide a mixed supply of a desired temperature. Controls are provided for such valves, commonly incorporating a rotatable control knob.

Where such mixer valves are used for domestic applications, it has also been proposed to provide an overridable stop intermediate the minimum and maximum temperatures selectable by the valve. In particular, a control knob may be varied between its minimum temperature setting and the intermediate temperature setting freely.

However, to obtain temperatures above the intermediate temperature, the overridable stop must be overcome. This provides a safety feature to prevent particularly the young or infirm accidentally selecting undesirably high temperatures. Various mechanisms have been proposed for providing the overridable stop and for providing buttons to overcome that stop. In particular, it is known to provide buttons which may be depressed in order to overcome the stop.

The various mechanisms which have been proposed suffer from a number of problems. Many of the mechanisms are unduly complicated and bulky. They require the provision of an unsightly protruding button on the control and they require operation of the button even when the control knob is being moved from a high temperature setting to a safe low temperature setting.

The present invention seeks to overcome these problems.

According to the present invention, there is provided a control having a rotatable control knob with an overridable stop for preventing rotation of the control knob in only one direction of rotation, the control including a release button for releasing the overridable stop, the release button being movable from a first position proud of an outer surface of the control to a second position generally flush with the outer surface so as to release the overridable stop; wherein the release button is arranged to move from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop.

In this way, during normal operation of the control knob, the release button need not protrude from the control knob or be unduly is visible. Only when the control knob is moved to the point of the overridable stop does the release button appear for operation. Then, the release button is pushed back into the control to be turned further.

Preferably, the release button is provided with an engaging member which engages with a cam surface which rotates relative to the engaging member with rotation of the control knob, the cam surface including an inclined portion for guiding the release button from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop.

In this way, the release button is guided positively to its first position. In particular, in the final part of its rotation to the overridable stop, the release button may be gradually and smoothly guided to its first position. This provides a pleasing operation to the user and, by avoiding any sudden changes of position to the release button, reduces wear.

Furthermore, when it comes to moving the control knob in the reverse direction, the inclined surface allows the release button to be moved back automatically to its second position without any intervention by the user.

Preferably, the cam surface further includes a generally radial portion forming the overridable stop and against which the engaging member abuts to prevent rotation of the control knob.

Hence, the overridable stop may be provided integrally with tile cam surface and without the need for any additional components.

The release button and the engaging member may be together sprung radially outwardly with the cam surface facing radially inwardly.

Alternatively, the release button may be sprung radially outwardly with the engaging member provided on an extension of the release button at a diametrically opposite side to the release button such that it is sprung radially inwardly with the cam surface facing radially outwardly.

Indeed, according to the present invention, there is provided a control having a rotatable control knob with an overridable stop for preventing rotation of the control knob, the control including a release button for releasing the overridable stop wherein the release button is provided with an engaging member and engages with a cam surface, the engaging member being provided on an extension of the release button at a diametrically opposite side to the release button.

In this way, the release button mechanism may conveniently be constructed in a control of small size. By extending movement of the release button across the diameter of the control knob, the entire diameter of the control knob may be used to house the release button mechanism, rather than just its radius. Since embodiments may include biassing springs and guides to limit movement of the release button and engaging member,, this additional space provides significant advantages in allowing a less complicated, less expensive and more robust construction.

Preferably the cam surface is rotationally adjustably positioned so as to adjustably position the overridable stop relative to the fall rotational extent of the control knob.

In this way, by setting the cam surface at various different rotational orientations, the control knob reaches the overridable stop at different positions. Thus, by selecting a particular position for the cam surface, a user may select a particular position for the overridable stop.

Preferably, the outer surface is an outer surface of the control knob, such that the release button rotates with the control knob.

In this way, the release button mechanism is housed within the control knob and the cam surface is provided on another portion of the control.

The -control may be used for any device requiring rotational movement. However, a preferred application for the control is with a fluid valve, particularly a fluid valve for mixing fluids of different temperatures, such that the control knob controls the outlet mixed temperature and the overridable stop defines an upper intermediate overridable temperature limit.

The invention will be more clearly understood from the following description, given by way of example only, with reference to the accompanying drawings, in which:

Figures 1 and 2 illustrate a control embodying the present invention; Figure 3 illustrates the control knob of the embodiment of Figures 1 and 2; Figure 4, 5 and 6 illustrate the control base of the embodiment of Figures 1 and 2; Figures 7 and 8 illustrate two positions of the release button of the control knob of Figure 3; Figures 9 and 10 illustrate respectively the control base and control knob of an embodiment of the present invention; Figures 11 and 12 illustrate positions of the release button of the control knob of Figure 10; and Figure 13 illustrates the control base of Figure 9 with the cam is surface removed.

Referring to Figures 1 and 2, the control includes a control knob 2 with a release button 4. The control knob 2 and release button 4 rotate together relative to a control base 6 (not shown in Figures 1 and 2) and rotate an operating member 8. The operating member 8 can be of any suitable shape and size to engage the device under control. In the preferred embodiment, the control is used to operate a fluid mixing valve for mixing hot and cold water. Thus, in this embodiment, the operating member 8 is used to engage the fluid mixing valve.

In the illustrated embodiment, the control base 6 is fixed relative to an internal shaft about which the control knob 2 and the operating member 8 rotate.

The control knob 2 is rotatable relative to the control base 6. In the preferred embodiment, where the control knob operates a mixing valve, the control knob 2 may be constrained to rotate between two predetermined limits. These limits may be determined by the limits of rotation of the mixing valve itself.

The control is provided with an overridable stop such that in one direction of rotation, the control knob 2 is prevented from further rotation. For most of the range of rotation, the release button 4 lies generally flush with the outer surface of the control knob 2, in other words in its depressed position as illustrated in Figure 1. However, at the point of the overridable stop, the release button 4 moves outwardly of the control knob 2 so as to be proud from the control knob surface as illustrated in Figure 2. By manually depressing the release button 4 inwardly of the control knob 2, the overridable stop is overcome and further rotation of the control knob 2 is possible.

In the preferred embodiment, the overridable stop is provided at an intermediate mixing temperature. In this way, the control knob 2 can be rotated from the minimum temperature to the intermediate temperature defined by the overridable stop. However, to select higher temperatures, the release button 4 must be depressed to overcome the stop.

When the control knob 2 is rotated in the reverse direction, the overridable stop does not take effect. The release button 4 may or may not move outwardly of the control knob 2, but no depression by the user is necessary.

The control knob 2 and release button 4 are not limited to the shapes or designs illustrated in Figures 1 and 2, but can take other aesthetically pleasing designs. Alternatively, the control knob 2 may incorporate an outer decorative shell and the release button may include a decorative covering.

Figures 3 to 6 illustrate the control knob 2 separated from the control base 6. In particular, Figure 3 illustrates the underside of the control knob 2 and Figures 4, 5 and 6 illustrate the exposed facing side of the control base 6.

As illustrated particularly in Figure 6, the control base 6 includes a cam surface 10. In this embodiment, the cam surface 10 is formed on the radially outwardly facing surface of a wall 12. The cam surface 10 includes a generally radial portion 14 which forms the overridable stop of the device and also an inclined portion 16 which operates to guide the release button 4 out of the control knob 2 prior to the overridable stop.

The control base 6 also includes a small wall 15. This is a preferred feature which is used to ensure that the cam surface 10 is followed.

Referring to Figure 3, it will be seen that the release button 4 is provided with an engaging member 18. The engaging member 18 extends axially from the control knob 2 so as to engage with the cam surface M In this way, the engaging member 18 and, hence, the release button 4 follow the cam surface 10.

As illustrated in Figures 7 and 8, as well as Figure 3, a spring 20 is provided to bias the release button 4 outwardly from the control knob 2.

It will be seen that the engaging member 18 is provided on an extension 22 of the release button 4. The extension 22 extends generally across a diameter of the control knob 2 so as to provide the engaging member 18 at a position generally diametrically opposed to the release button 4. In this way, the biassed outward movement of the release button 4 is converted to a biassed inward movement of the engaging member 18.

Where the control and, in particular, the control knob 2 are of a small size, this design is particularly advantageous. In particular, it allows the mechanism of the release button and overridable stop to be spread over the distance of the diameter of the control knob, rather than merely its radius. Incorporating an engaging member, a biasing spring and suitable movement guidance components between the surface of the control knob and the centre of the control knob can be very complicated, expensive or unreliable. The mechanism illustrated in the figures provides a more straightforward, accurate and robust operation.

During operation of the control, the engaging member 18 is normally held away from the centre of the control knob 2 by the cam surface 10, such that the release button 4, extension 22 and engaging member 18 take the position illustrated in Figure 8. When the control knob 2 is rotated to the position such that the engaging member reaches the inclined portion 16, the engaging member 18 is then allowed gradually to move towards the centre of the control knob 2. During this process, the extension 22 and release button 4 also gradually move towards the position illustrated in Figure 7. Upon further rotation of the control knob 2, the engaging member 18 abuts the radial portion 14 of the cam surface 10. Thus, no flu-ther rotation of the control knob 2 is possible until the user depresses the release button 4, thereby moving the engaging member 18 outwardly of the control knob 2 and past the radial portion 14 of the cam surface 10.

In the illustrated embodiment, the cam surface 10 continues at an extended radius, such that the release button 4 is held in the position of Figure 8 for further rotation.

As will be clear from the figures, upon rotation of the control knob 2 in the reverse direction, when the engaging member 18 reaches the radial portion 14 of the cam surface 10, the release button will move from the position illustrated in Figure 8 to that illustrated in Figure 7.

Further rotation of the control knob 2 in the reverse direction will then result in the inclined portion 16 of the cam surface 10 gradually guiding the release button 4 back to the position illustrated in Figure 8 The wall 15 is provided to ensure that the engaging member 18 does follow the inclined portion 16 and radial portion 14. In particular, it prevents accidental movement past the stop, for instance by inadvertently holding down the release button 4.

The cam surface 10 may be mounted to the control base 6 in an adjustable manner such that the rotational position at which the overridable stop occurs may be adjusted relative to the control base 6 and any mechanism, such as the fluid mixing valve, to which it connects. In this way, for the embodiment in which the control is used with a temperature mixing valve, the user may choose the intermediate temperature at which the overridable stop occurs.

As illustrated in Figure 5, the control base 6 is formed from two axially separable components 6a and 6b. The central component 6a supports the cam 10 and, when separated from the outer component 6b, is rotatable about a shaft 6c. Furthermore, as illustrated, the central component 6a has a series of outwardly facing teeth for engagement with a corresponding series of inwardly facing teeth on the outer component _10 6b. In this way, when the central component 6a. is moved axially into engagement with the outer component 6b, the central component 6a and the cam 10 become rotationally fixed relative to the outer component 6b and shaft 6c. By using the teeth to engage the central component 6a and cam 10 in different orientations, the relative position. of the releasable stop can be changed. For instance, by providing 120 teeth around the circumference, the position of the stop can be varied with 3' intervals.

As illustrated in Figures 4 and 5, a latch 7 is also provided rotatably on shaft 6c. The latch 7 is generally cylindrical, but includes a cut-out portion 7a corresponding to an inwardly extending section 12a of wall 12. As illustrated in Figure 5, when the cut-out portion 7a. is aligned with the section 12a,, section 12a can move into the cut-out portion 7a and, hence, the central component 6a. can move axially out of engagement with the outer component 6b. In contrast, in all other positions of latch 7, as illustrated in Figure 4, latch 7 abuts against section 12a and holds the central component 6a into engagement with the outer component 6b.

It is possible to provide markings to assist the user in making adjustments to the position of the cam 10. In particular, the central component 6a may include a pointer and/or gradations and/or an indication of hotter or colder. In use, these can be moved relative to markings provided on an outer housing of the assembly (themselves provided for adjustment of the control knob 2 during normal use).

Alternatively, the markings can be provided on the outer component 6b.

Referring to Figures 7 and 8, it will be seen that the extension 22 is provided as a generally ring-shaped portion around the centre of the control knob 2. By providing the extension 22 as an elongate section, in particular having two generally parallel opposite sides, it is possible to make use of the extension 22 to guide movement of the engaging member 18. Nevertheless, the illustrated embodiment includes an additional means for guiding the engaging member 18. In particular, a raised wall 24 is provided radially on the control knob 2. A corresponding channel (not illustrated) is then provided in the extension 22 opposite the engaging member 24. In this way, the channel and hence the extension 22 and engaging member 18 are guided by the wall 24.

The illustrated embodiment includes a cam surface 10 provided on the control base 6 and a movable engaging member 18 and release button 4 provided in the control knob 2. However, it should be appreciated that the location of these functional components can be reversed. In particular, it is also possible to provide the cam surface 10 in the control knob 2 and provide the release button and its associated mechanism in the control base 6.

Figures 9 and 10 illustrate the control base 6 and control knob 2 of an alternative embodiment. This embodiment differs from that described above principally by having an engaging member 18 on the same radial side of the control knob 2 as the release button 4. Since the engaging member 18 is radially biassed outwardly of the control knob 2, the cam surface 10 is provided as an inwardly facing surface.

With the control knob 2 of Figure 10, a mechanism is provided (not shown) for biassing the control knob 4 and its associated engaging member 18 outwardly of the control knob 2. As with the previous embodiment, the engaging member 18 extends axially from the control knob 2 and engages against a cam surface 10. The cam surface 10 has a radial portion 14 acting as the overridable stop and an inclined portion 16 which allows the engaging member 18 and release button 4 to move outwardly of the control knob 2 as they approach the radial portion 14.

Thus, the release button 4 and engaging member 18 move from the position illustrated in Figure 12 to that illustrated in Figure 11. By manually depressing the release button 4 and moving it from the position illustrated in Figure I I to that illustrated in Figure 12, the engaging member 18 is moved radially inwardly and may then continue along the remaining path of the cam surface 10.

In the illustrated embodiment, rotation of the control knob 2 is transferred through the control base 6 via an intermediate ring 26. In particular, the control knob 2 may be attached to the intermediate ring 26 by means of screws (not illustrated) in holes 28 and 30. In this embodiment, a central portion 32 may extend through a hole 34 in the control knob and allow engagement with a further control knob (not illustrated). In this way, the control knob 2 may be presented to the user as a ring by which temperature may be adjusted and the other, control knob (which is not illustrated) may be used to control through flow.

Figure 13 corresponds to Figure 9, but with the central component 6a and cam surface 10 removed. As can be seen from this figure, just as with the embodiment described above, the cam surface 10 is connected to the outer component 6b of the control base 6 by means of a series of teeth. As described for the previous embodiment, the position of the overridable stop may thus be chosen by the user according to individual requirements.

It is also possible for the cam surface 10 to be formed on an outer angular part of the control base 6 and to engage with outwardly extending teeth of a fixed central portion of the control base 6. In particular, the cam surface 10 can be formed as a ring with an inwardly facing series of teeth or spline arranged to engage with the outwardly facing teeth or spline of the control base 6. In this way, the rotational position of the cam surface 10 may be adjusted relative to the control base 6.

As with the previous embodiment, it is also possible to reverse the location of the components, in other words, to provide the cam surface on the control knob 2 and the release button 4 on the control base 6.

It is possible to provide markings on the two relatively movable components of the control base in a similar way to that described for the embodiment described above. This is illustrated in Figure 9 where a central pointer and "Hot" and "Cold" markings are provided on the central component 6a and gradations 40 are provided on the outer component 6b.

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Claims (16)

1. A control having a rotatable control knob with an overridable stop for preventing rotation of the control knob in only one direction of rotation, the control including a release button for releasing the overridable stop, the release button being movable from a first position proud of an outer surface of the control to a second position generally flush with the outer surface so as to release the overridable stop; wherein the release button is arranged to move from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop.

2. A control according to claim I wherein the release button is provided with an engaging member which engages with a cam surface which rotates relative to the engaging member with rotation of the control knob, the cam surface including an inclined portion for guiding the release button from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop.

3. A control according to claim 2 wherein the cam surface finther includes a generally radial portion forming the overridable stop and against which the engaging member abuts to prevent rotation of the control knob.

4. A control according to claim 2 or 3 wherein the release button and the engaging member are together sprung radially outwardly and the cam surface faces radially inwardly.

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5. A control according to claim 2 or 3 wherein the release button is sprung radially outwardly, the engaging member is provided on an extension of the release button at a diametrically opposite side to the release button such that it is sprung radially inwardly and wherein the cam surface faces radially outwardly.

6. A control having a rotatable control knob with an overridable stop for preventing rotation of the control knob, the control including a release button for releasing the overridable stop wherein the release button is provided with an engaging member and engages with a cam surface, the engaging member being provided on an extension of the release button at a diametrically opposite side to the release button.

7. A control according to claim 6 wherein the release button is sprung radially outwardly and, hence, the engaging member is sprung radially inwardly, the cam surface facing radially outwardly.

8. A control according to claim 6 or 7 wherein the overridable stop prevents rotation of the control knob in only one direction of rotation and the release button is movable from a first position proud of an outer surface of the control to a second position generally Rush with the outer surface so as to release the overridable stop, the release button being arranged to move from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop.

9. A control according to claim 6, 7 or 8 wherein the cam surface includes an inclined portion for guiding the release button from the second position to the first position as the control knob is rotated in said one direction approaching said overridable stop.

10. A control according to any one of claims 6 to 9 wherein the cam surface further includes a generally radial portion forming the overridable stop and against which the engaging member abuts to prevent rotation of the control knob.

11. A control according to any one of claims 2 to 10 wherein the cam surface is rotationally adjustably positioned so as to adjustably position the overridable stop relative to the full rotational extent of the control knob.

12. A control according to any preceding claim wherein the outer surface is an outer surface of the control knob such that the release button rotates with the control knob.

13. A fluid control valve including a control according to any preceding claim.

14. A fluid control valve according to claim 13 for mixing fluids of different temperatures wherein the control knob is for controlling outlet temperature and the overridable stop defines an upper overridable temperature limit.

15. A control constructed and arranged substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

16. A fluid control constructed and arranged substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.