GB2443641A

GB2443641A - A button having travel limited by a friction fitted bush

Info

Publication number: GB2443641A
Application number: GB0622348A
Authority: GB
Inventors: Robert Anthony Smedley Kay; Clive David Silver
Original assignee: DANLERS Ltd
Current assignee: DANLERS Ltd
Priority date: 2006-11-09
Filing date: 2006-11-09
Publication date: 2008-05-14
Also published as: GB0622348D0

Abstract

An activator such as button 120 that in use engages with an electric or fluid control means 170 has a retainer 200 that allows the activator to move relative to the retainer upon initial introduction of them during assembly but preventing relative movement of them thereafter, with movement of the activator 120 in use being restricted by the retainer 200. The activator 120 extends through a face plate 112, and the retainer 200 may be a nylon or plastic bush or collar which is a friction fit on a pin 140 of the activator. A bush retainer (82, figs 1 and 2) may screw into an aperture (90, figs 1 and 2) in the faceplate. The head of the button 120 fits within a recess to give a low profile that avoids damage. An extension (292, figs 5 and 6) clipped into the retainer can engage the control means. Manufacturing tolerances can be addressed by the position of the retainer 200 relative to the button 120. The activator can replace a touch-sensitive plate in a light dimmer control.

Description

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RETAINING MEANS

This invention relates to retaining means for retaining an activator member in movable relation to a control assembly, and to an electrical control assembly.

In particular, although not exclusively, the invention relates to an electrical control assembly having control means for effecting the characteristics of an electrical supply, an activator member and retaining means for retaining the activator member in movable relation to the control assembly.

In the field of electrical control systems potentiometers are used for varying the potential of an electrical supply. The variation of the potential is used to vary the brightness of electrical lights or the speed of fans etc. Such potentiometers are often used in domestic or office situations and are mounted on the wall for use by a user, in a similar manner to a light switch. They are often referred to as "dimmer switches". These potentiometers may be either controlled by : * rotation of a spindle or by the pressing of a button, although other methods are S...

also possible. In either case, a spindle, or other rod-like member protrudes from an electrical unit, through a face plate. A cover, or cap, is then placed * over the spindle or rod to improve the aesthetic appearance. Typically, the cover cap protrudes away from the face plate, behind which the electrical * :* system is installed, by approximately 10mm, and sometimes more. )

Such control devices are prone to damage, via either vandalism, or being knocked against, since they protrude outwardly into the room.

One way to avoid having a protruding knob is to provide a touch-sensitive face plate. These devices have a smooth face plate with no necessary discemable features thereon. The user activates them by merely touching them with a finger. However, it has been found that many users do not like these touch-sensitive control devices since there is no tactile interaction with them, in that there is no positive "click".

Accordingly, it is desirable to have a control device, which may be used for controlling electrical devices, which is low-profile such that it does not protrude so far as to be prone to damage, is difficult to access so that no cover, or over-cap, may be removed, and yet still provides tactile interaction.

The present invention aims to overcome this problem and provide improved : ***, apparatus in the field of control assemblies. S... S... * *

In one aspect, the invention provides retaining means for retaining an activator member in movable relation to an electrical control assembly, of the type where the activator member is engageable with control means for affecting the * :* characteristics of an electrical supply through the respective movement of the activator member with the control means, the retaining means being arranged to permit the activator member to move relative to the retaining means upon ) initial introduction of the activator member to the retaining means, and the retaining means being arranged to prevent the activator member being able to move relative to the retaining means thereafter, whereby in use, the movement of the activator member is restricted by the retaining means.

The retaining means may have a bore or other means for receiving at least part of the activator member which may be insertable therethrough upon initial introduction of the activator member to the retaining means.

The retaining means may be initially separate from the activator member and arranged to retain the activator member in fixed relation thereto by a friction-fit between the retaining means and at least part of the activator member.

For instance, the retaining means may have a hole or bore therethrough and at least part of the activator member may be engageable with the bore such that once it has been inserted in the bore the activator member and retaining means : * *. become fixed together. This fitting of the activator member to the retaining S... . . . ***,. means may occur upon initial installation.

* S.... * .

Friction between part of the activator member and the retaining means may be provided by splines, ribs, ridges or flaps etc. orientated axially or radially along the inside surface of the bore. Alternatively, or additionally, such splines, ridges, ribs or flaps etc. may be provided on the corresponding (possibly outer surface) of the part of the activator member which comes into contact with the ) retaining means. Alternatively, or additionally, the bore running through the retaining means does not have to be circular in cross-section but could be of other shape, such as triangular or square, so that the bore grips the relevant part of the activator member to prevent relative movement therebetween after the initial installation.

In another aspect, the invention provides an electrical control assembly having control means and an activator member engageable with the control means for affecting the characteristics of an electrical supply through the respective movement of the activator member with the control means, the control assembly having retaining means, having any combination of the features described herein, for retaining the activator member in movable relation to the control means.

The activator member may have a dome-shape head, and an elongate element depending therefrom which is receivable by the retaining means and which is : ** contactable, either directly or indirectly, with the control means to affect its p...

**.e. . . operation. The control means may be in the form of a micro-switch which is biased to the open, inactive position. The biasing means may be in the form of a belleville-type spring. Pressure on the switch, possibly from the elongate member, overcomes the biasing of the switch thus moving it to the closed, operative position. When pressure on the button is removed, the switch reverts to its open, inoperative position, due to the biasing means. The head could be concave, or flat as well as being convex or dome shape. )

The control assembly may include a housing, with a recess, the housing accommodating the retaining member such that after initial installation the retaining means may retain part of the activator member in the recess in the housing.

The activator member may be introducible to the retaining means from outside the assembly. Thus a method of installing a new control assembly may have the steps of providing a cavity for the control assembly, introducing the assembly into the cavity, attaching a face plate, having an aperture provided therein, over the assembly, introducing the retaining means into the assembly, via the aperture in the face plate, and introducing, or pushing, the activator member (or button) into the retaining means (or collar) until its movement is arrested by the control means.

The face plate may of course already be attached to the assembly. Further, the cavity could be in a wall or provided by a surface mounted box. J.. * * *

If the activator member has an elongate member (or pin) then this may be : pushed through a hole in the collar until the end of the pin contacts against the switch in the control means. During installation of the pin the button may :. move relative to the collar. However, once the end of the pin has contacted * *I.

* : against the switch the relative movement between the pin and collar ceases.

Thereafter the pin and collar move as one due to the friction fit between the pin and collar. )

The activator member may move in a reciprocating fashion with respect to the control means. Alternatively, and/or additionally, the activator member may rotate with respect to the control means or assembly. This is because the control means may have a reciprocating contact-type switch or a rotational-type device.

The activator member may be biased in one direction by the control means.

For instance, the activator member may be biased towards the face plate and away from the control means.

The control means may vary the potential of an electrical supply. In one embodiment, the assembly is a dimmer controller for a lighting circuit.

The present invention and its advantages will be better understood from the following detailed description in which reference is made to the attached Figures, in which; a s. * * S a

Figure 1 is a side view of one embodiment of part of an electrical control assembly with the activator member in a first position; * a..... a *

Figure 2 is a side view of the control assembly Figure 1 with the activator member in a second position;

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Figure 3 is a side view of a different embodiment of an electrical control assembly with the activator member in a first position; Figure 4 is a side view of the control assembly of Figure 3 with the activator member in a second position; Figure 5 is a side view of yet another embodiment of an electrical control assembly with the activator member in a first position; and Figure 6 is a side view of the control assembly of Figure 5 with the activator member in a second position.

The electrical control assembly 10 shown in Figure 1 includes control means for effecting the characteristics of an electrical supply. For instance, the control means could be a potentiometer for varying the potential of an electrical supply. One example of such an electrical control assembly is a ::::. dimmer switch for dimming electrical lights.

Only part of the electrical control assembly 10 is shown, with other components having been omitted to improve the clarity. * * *

*....: * A face plate 12 lies on one side of the assembly so that when the assembly is installed, for instance in a wall cavity, only the face plate 12 is visible. A threaded aperture 90 is provided in the face plate 12. Within the control assembly 10, the control means 70 are provided, access to the control means 70 being via the aperture in the face plate 12. Once the control assembly 10 has been installed in a cavity, or otherwise, a bush (or collar) 100 is inserted and a bush retainer 82 is screwed into the aperture 90 by means of corresponding threads. The aperture within the bush retainer 82 may have a hexagonal shape for interengagement with a hexagonal spanner such that it can be tightened against the face plate 12. The bush retainer 82, which may be made of metal, nylon, or plastics, also has a flange 85 which projects radially inwardly thus retaining the bush 100 within the aperture 90. The bush 100 which may be nylon or plastics in constitution, has a hole running through it from one side to the other. This hole is aligned with a socket 65 in the control means 70 and may pass through the centre of the bush 100 but may also pass through non-centrally. At the base of the socket 65 a control switch 60 is provided. This switch is resiliently biased so that it may reciprocate towards and away from the bush 100.

: ** Once the bush retainer 82 has been fitted to the assembly 10, an activator S...

member (or button 20) is introduced. This button 20 has a mushroom shape head part which fits within the shoulders 80 of the bush retainer 82, and a pin 40 depending from the head. The pin 40 is inserted into the aperture 90 and through the hole, or bore, within the bush 100. The pin 40 is pushed through

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S..... . . the hole until the end of the pin 50 comes to rest against the switch 60 in the socket 65 of the control means 70.

Due to a friction fit provided between the hole in the bush 100 and the pin 40 the bush 100 is pressed against the end of the control means 70 by the action of inserting the pin 40. The bush 100 acts to retain the pin 40 and hence the button 20 within the assembly 10.

The bush 100 may move relative to the assembly towards and away from the control means 70 since its size is less than the distance between the control means and the underside of the flange 85 in the bush retainer 82. Due to the bush 100 being smaller than this size, a gap 86 is provided between the bush 100 and the flange 85 when the button 20 is initially installed. In Figure 1, the button 20 is shown as though pressure is being applied to it axially towards the control means 70.

When this pressure is released, the resilient means in the switch 60 will urge the pin 40 and thus the button 20 axially away from the control means 70. This is shown in Figure 2. Due to the friction fit between the pin 40 and the hole in : . the bush 100, the bush 100 moves with the button 30 away from the control ***. *.S.

S..... means 70 such that the gap 86 is reduced and a corresponding gap 87 is created *...: between the bush 100 and the control means 70. It will be seen that the end of a the pin 50 has moved away from the switch 60 and that the switch 60 has been resiliently urged away from the control means 70 towards the face plate 12. In U.....

: the configuration shown in Figure 2, the control means are inoperative and are not affecting the characteristics of an electrical supply, contrary to the situation shown in Figure 1.

When the head of the button 20 is in the inoperative position as shown in Figure 2, there is a very slight gap between the outer radial edge of the head of the button 20 and the shoulder 80 of the bush retainer 82. These drawings are only representational and although a relatively large gap is shown between the outer radial edge of the head of the button 20 and the shoulder 80, this gap would be minimised for production purposes such that the button 20 could not be prised out of the apparatus thus providing some protection against vandalism. Further, the button may be such that it has a smooth rounded outer surface thus making it very difficult to obtain any purchase for the purpose of attempting to remove it.

An important aspect of the present invention is that provided by the bush 100.

Due to tolerances during manufacture, the position of the control switch 60 may vary from control assembly to control assembly with respect to the face plate 12. Such tolerances are typically only of the order of fractions of a millimetre, however, since the control switch 60 need only be moved : .. approximately 0.5mm (and hence the button 20 need only be depressed *0..

approximately a respective 0.5mm) to alter its state from inoperative to operative, such tolerances need to be addressed for quality control purposes.

Further, the present invention compensates for face plates 12 having differing thicknesses which affects the distance between the head of the button 20 and I..., the switch 60. For instance face plates 12 typically have a thickness of between 0.9 and 2.5mm. )

One way to address these tolerances is by means of the bush 100. This is because the position of the bush 100 relative to the button 20 is not fixed but rather is dependent on the initial installation of the button and pin 40 into the assembly 10. This is because on installation, the pin 40 travels through the hole in the bush 100 until the end of the pin 50 contacts against the switch 60.

During this initial installation, the bush 100 moves relative to the button 20 since one side will be forced against the control means 70 as the pin 40 is travelling through the hole. As soon as the end of the pin 50 reaches the limit of travel, the bush 100 ceases to move relative to the pin 40. However, due to the friction fit between the pin 40 and the hole through the bush 100, the position of the bush 100 relative to the button 20 thereafter remains constant because the hole within the bush 100 grips the pin 40. Although a hole and a pin have been described other ways of introducing and retaining the activator member with the retaining means are contemplated. Since the bush 100 has a thickness which is less than the distance between the control means 70 and the underside of the flange 85, the bush may move within that space and hence the : *", button may move relative to the control means 70 and control assembly 10. *. *. s.

However, the button 20 cannot be removed from the control assembly 10 since : .: the bush 100 retains it in the control assembly 10 by means of a friction fit.

If the control means were slightly further away from the face plate 12 than shown in Figure 1, due to manufacturing tolerances, the end of the pin 50 would have to travel further, relative to the face plate 12, before contacting against the switch 60, and thus the bush 100 would be positioned slightly closer ) to the head of the button 20 than shown in Figure 1. However, the control assembly would still operate in the same way in that the bush 100 would allow the button 20 to move reciprocatively in relation to the control assembly 10 in order to effect operation of the switch 60.

The head of the button 20 may be dome shape with the apex of the dome being less than 3mm distant from the outer surface of the shoulder 80. More preferably this distance is only 1mm and in some embodiments may be flush with or recessed behind the outer surface of the shoulder 80.

An alternative embodiment of an electrical control assembly 110 is shown in Figures 3 and 4. The only difference between this embodiment and the one shown in Figures 1 and 2 is that an initially separate (from the assembly) bush retainer is not present. Rather, the bush 200 is pre-assembled into the control assembly 110 in a position between the control 170 and the underside of the face plate 112. The means for retaining this bush 200 within the assembly are not shown for the sake of improving clarity. However, it will be seen that the :.:::. aperture within the face plate has a diameter which is smaller than the bush 200 *..s so that it cannot be removed via the aperture. Further, other components necessary for the functioning of the control assembly 110 are also not shown :

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for clarity purposes. S. * S * *.* S *

The installation of the button 120 is identical to that discussed with regard to Figures 1 and 2. In other words, the button 120 is introduced to an aperture within the face plate 112 such that a pin 140 depending from the underside of the head of the button 120 passes through a hole within the bush 200 until the end of the pin 150 contacts against the control switch 160 in the socket 165 of the control means 170. Once the button 120 has been installed the bush 200 allows slight axial movement of the button 120 and bush 200 together relative to the control assembly 110. A friction fit exists between the hole in the bush and the pin 140 so that upon the completion of the initial installation of the button 120, the bush 200 is fixed relative to the button 120. A gap 186 allows the bush 200 and button 120 to move very slightly (approximately 0.5mm) away from the control switch 160 so as to move the button 120 into the inoperative position. This inoperative position is shown in Figure 4 where it may be seen that the control switch 160 has been urged away from the control means 170 towards the head of the button 120 so that a gap 187 is created between the control means 170 and the bush 200. This is due to resilient means provided within the control switch 160.

The head of the button 120 fits within a recess of the face plate 112 so that the shoulder 180 of the recess of the face plate 112 surrounds the circumference of **..

the head of the button 120. In this way, the button 120 is provided in a low

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*5*...

: 20 profile manner. This low profile characteristic avoids undue damage, whether

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deliberate or accidental and prevents the button 120 being prised out. The head

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of the button 120 may be dome shape with the apex of the dome being less than S.....

3mm distant from the outer surface of the face plate 112. More preferably this distance is only 1mm and in some embodiments may be flush with or recessed behind the outer surface of the face plate 112.

In Figures 5 and 6 a different embodiment of a control assembly 210 is shown.

This assembly 210 operates in a similar manner to that described above with regard to Figures 1 to 4 and has the same advantages. However, rather than the end of the pin 250 acting directly on the switch 260, provided in the socket 265 in the control means 270, a switch extension member 292 acts on the switch 260. This extension member 292 may be permanently fixed to the switch 260.

At the end of the extension member 292 distal from the switch 260 a clip 294 in the form of a radial projection is provided. This clip 294 fits inside a recess 302 at one end of the bush 300. The clip retains the bush 300 and the control means 270 together via the extension member 292. The clip 294 may be permanently secured to the bush once fitted to the recess 302 in the bush 300.

The end 250 of the pin 240 does not come necessarily into contact with the extension member 292, however, the end 250 of the pin 240 may extend into a * socket 296 within the extension member 292. Rather, the friction fit between the pin 240 and the hole through the bush 300 maintain the bush 300 and the : button 220 together in fixed relationship such that movement of the head of the : * * button 220 effects respective movement of the bush 300, the extension member * * * 292 and hence the switch 260.

*....: * ) Accordingly, when the pin 240 is initially introduced into the hole in the bush 300 it is not the end of the pin 240 abutting against the switch 260 which limits the relative movement between the bush 300 and the button 220. Rather, it is the underside of the head of the button 220 abutting against the upper side of the flange 285 which prevents further movement. Since the action of pushing the pin 240 into the hole in the bush 300 moves the bush 300 and the extension member 292 to the active, or operative, position of the switch 260, as soon as the initial pressure is released, the biasing means will urge the switch 260 to the inactive, or inoperative, position and hence urge the extension member 292, the bush 300 and the button 220 away from the switch 260 to the position shown in Figure 6. The button 220 will then be movable relative to the control switch 160. Its movement is limited by the amount of travel within the switch 260 between the inactive and active positions to thus operate the control switch The shoulder 280 shown in Figures 5 and 6 could stand more proud of the face plate 212 such that the outer surface of the button is flush, or recessed, with * S. respect thereto. This would make it difficult for anyone to prise the button 220 **s out of the assembly 210.

*....: : * Another difference between this embodiment and the embodiment described *.

: with reference to Figures 1 and 2 is that the aperture within the face plate 212 *S.*.S

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does not have a threaded section depending towards the inside of the control assembly 212. Rather a threaded section 290 is provided on the radially inside surface of the aperture within the assembly 210 for receiving the bush 300, the bush retainer 282 and pin 240. The threads on the outer radial surface of the bush retainer 282 engage with the threads 290 on the inner radial surface of the aperture. The bush retainer 282 may be tightened against the face plate 212 by means of a hexagonal spanner, for instance. The face plate 212 fits over the upper surface 211 of the assembly 210 and around an upstanding collar 213 provided on the upper surface 211 immediately adjacent and around the perimeter of the aperture within it. Other alternatives are possible such as the threads on the bush retainer 282 engaging with the edge of the aperture in the face plate 212 or upper surface 211 of the assembly 210. Further, rather than corresponding threads, other means of retaining the bush retainer 282 in association with the assembly 210 are of course possible.

This embodiment includes a shoulder 266 on the underside of the head of the button 220. This shoulder may limit the movement of the button 220 with respect to the bush 300. * S.

:..* In Figure 5 the assembly 210 is shown with the button 220 in the active, or *.S.

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operative, position. However, in Figure 6, the gap 286 between the bush 300

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*55**5 and the flange 285, shown in Figure 5, has been reduced and instead a gap 287 :

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:. has been created between the bush 300 and the control means 270. However, * . the relative positions of the pin 240 and the bush 300 have remained constant.

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In this embodiment, the bush 300 may be inserted via the aperture in the face plate 212, or could be pre-assembled to the control means 270. Alternatively, the invention could take the form of a combination of the embodiment described above, with reference to Figures 3 and 4, and this embodiment so that there is no bush retainer 282 and the bush 300 is pre-assembled into the control assembly 210.

In the embodiments described, the only resilient means provided for urging the button 20, 120, 220 to the inoperative position is provided within the switch 60, 160, 260. However, additional resilient means could be provided to act directly on the bush 100, 200, 300, button 20, 120, 220 or extension member 292, as necessary.

In Figure 2, a small gap exists between the end of the pin 50 and the switch 60 when the button 20 is in the inoperative position. This small gap would mean that the button 20 would have to be moved slightly before the end of the pin 40 contacts the control switch 60. By contrast, the end of the pin 150 is always in * contact with the switch 160 in the second embodiment as shown in Figure 3 **.. * ***.

and 4. Further, in the third embodiment the extension member 292 is always in : * 20 contact with the switch 260. These various possibilities are interchangeable *....: * between the embodiments described herein. ** * * * *S*

*....: * * In the embodiments the button 20, 120, 220 is introduced from outside of the control assembly 10, 110, 210. In the first and third embodiments the bush 100, 300 is also introduced from the outside of the electrical control assembly 10, 210 together with the bush retainer 82, 282. By contrast, in the second embodiment the bush 200 is already pre-installed into the assembly 1)0 and it is only the button 120 which is introduced from the outside.

The bush 100, 200, 300 acts as a collar for positioning the button 20, 120, 220 relative to the electrical control assembly 10, 110, 210.

Due to the low profile nature of the button 20, 120, 220 in relation to the face plate 12, 112, 212, it is extremely difficult to pnse the button 20, 120, 220 out of the assembly 10, 110, 120 once it has been initially installed. If the face plate is fixed to the wall, or other surface in which the assembly 10, 110, 210 is mounted, by the use of anti-tamper screws, then the whole apparatus becomes resistant to tampering and/or vandalism. Such installations are useful in public places, such as communal halls and landings in apartment buildings.

Although the invention has been described with reference to an assembly for * ** affecting the characteristics of an electrical supply it could also be used to S...

affect the characteristics of a fluid supply by suitable adaptation. : S * S. * . * *S.

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Claims

1. Retaining means for retaining an activator member in movable relation to an electrical control assembly, of the type where the activator member is engageable with control means for affecting the characteristics of an electrical supply through the respective movement of the activator member with the control means, the retaining means being arranged to permit the activator member to move relative to the retaining means upon initial introduction of the activator member to the retaining means, and the retaining means being arranged to prevent the activator member being able to move relative to the retaining means thereafter, whereby in use, the movement of the activator member is restricted by the retaining means.

2. Retaining means, according to claim I, having a bore for receiving at least part of the activator member insertable therethrough upon initial introduction of the activator member to the retaining means. * ** * * *

3. Retaining means, according to either of claims 1 and 2, initially separate from the activator member, and arranged to retain the activator member in fixed relation thereto by a friction-fit between the retaining means :. and at least a part of the activator member.

*....: *

4. An electrical control assembly having control means and an activator member engageable with the control means for affecting the characteristics of an electrical supply through the respective movement of the activator member with the control means, the control assembly having retaining means, according to any preceding claim, for retaining the activator member in movable relation to the control means.

5. An electrical control assembly according to claim 4, wherein the activator member has an elongate element which is receivable by the retaining means and which is contactable with the control means to effect control thereof.

6. An electrical control assembly according to either of claims 4 and 5, wherein the assembly includes a housing and part of the activator member is retainable by the retaining means in a recess in the housing.

7. An electrical control assembly according to any of claims 4 to 6, wherein the activator member is introducible to the retaining means from outside the assembly. * .1 * S * *S*i *SS*S *IS.

8. An electrical control assembly according to any of claims 4 to 7, wherein the activator member is movable reciprocatively with respect to the * control means. *. * S * *S*

*....: S *

9. An electrical control assembly according to claim 8, wherein the activator member is biased away from the control means.

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10. An electrical control assembly according to any of claims 4 to 7, wherein the activator member is rotatable with respect to the assembly.

11. An electrical control assembly according to any of claims 4 to 10, wherein the potential of an electrical supply is variable by the control means.

12. An electrical control assembly according to any of claims 4 to 11, wherein the assembly is a dimmer controller for a lighting circuit.

13. Retaining means substantially as hereinbefore described with reference to, and as shown in, the Figures.

14. An electrical control assembly substantially as hereinbefore described with reference to, and as shown in, the Figures. * * I * *S*. *1.I

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S S...' S *

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I I. * . * *S.

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