GB2399403A - A toggle switch with a rotatable power reducing or dimming bezel - Google Patents

Abstract

A switch has an on/off toggle switch 14 arranged concentrically within a rotatable bezel 16. The switch combines an on/off and a dimmer function for varying electrical power transfer between a power source and a load (eg a lamp). The toggle switch 14 is pivotally displaceable about an axis A2 between a first position where the toggle switch completes an electrical switching circuit and a second position where the circuit is broken. A dimmer or power circuit (fig 3) has a variable resistor 20 driven via a gear- or rubber-wheel 60 when the bezel 16 is manually rotated about the axis A2. The bezel 16 rotates through at least 90{. A traditional appearance can be achieved by making the bezel of bakelite or a metal (eg brass) with an insulated coating, and a pattress 12 of wood. Different gear ratios may be selected, or in one embodiment (not illustrated) the bezel could directly engage the resistor spindle 26.

Description

An Adiustable Electrical Switch The present invention is directed to

electrical switches used for varying the power transfer between a power source and load, such as a light bulb and, more particularly, to a switch having a manually displaceable actuator for varying such power transfer.

The use of electrical switches for controlling the switching of power between a power source and an electrical load is to be considered commonplace, particularly in the field of lighting circuits, where the switch is operable between a first and second actuated position, whereby in the first of these actuated positions the switch serves to complete an electrical lighting circuit between the power source and the load and, in the second position, it effectively breaks such circuit thereby switching the load or device off. Examples of such switches include conventional toggle switches, push button switches or sliding switches. Furthermore, the basic operation of such switches has been enhanced by providing additional means to vary the power transfer effected by such switches when the switching circuit is closed. Such switches are conventionally referred to as dimmer switches and operate on the principle of utilising an adjustable resistor within the switching circuit which is manually adjustable by operation of an appropriate dimmer switch actuator. In the case of push button switches, the push button itself is often made rotatable about an axis so as to operate an appropriate rheostat to provide the adjustable resistance of the switching circuit. An example of such a combined dimmer and on/off switch is disclosed in UK Patent Application No. 2289165 (Home Automation Limited) which discloses the basic principle of operation of such existing dimmer switches. Alternatively, for the use of lever switches or sliding switches, displacement of the lever or slider between two extreme positions not only effects on/off operation of the actual circuit but its relative position between these two extreme positions also effects variance of an appropriate variable resistor so as to vary power transfer through the switching circuit. An example of such a lever switch is disclosed in US Patent No.4675540.

However, a drawback of this type of dimmer switch is that if a preferred power setting is achieved by the operator of such a switch, this power setting cannot be maintained during an on/off switching function since the lever or slider switch must be returned to an extreme position to effect switching off of the circuit.

Other types of combined dimmer switches and on/off switches attempted to address this problem by providing a separate toggle switch, which is simply displaceable between a first and second operative position to define on/off switching of the switching circuit, in combination with a separate linearly displaceable actuator for separate control of the variable resistor of the dimmer circuit. An example of such a switch is shown in US Patent No.60053()8. 2()

Whilst these existing combined dimmer and on/off switches achieve their required objective in providing a means of providing adjustable power transfer through a switch, their various constructions necessitate modern aesthetic design of such switches which has been found to be incompatible for use in homes and buildings having traditional decor. Furthermore, traditional toggle switches not only retain a more aesthetic appeal, but also provide efficient tactile response of such electrical switches, being positively displaceable between two operative positions indicative of switching the circuit on or off. Modern push button switches provide no means of providing tactile feedback as to whether the circuit is switched on or switched off.

It is therefore an object of the present invention to provide an improved adjustable electrical switch combining the function of an on/off switch and a dimmer switch which alleviates the aforementioned problems associated with existing combined on/off and dimmer switches and is applicable to traditional switch designs.

According to the present invention there is provided an adjustable electrical switch for varying the power transfer between a power source and a load, comprising a base plate having a toggle switch mounted thereon and pivotally displaceable between a first and second operative position about a toggle axis extending perpendicular to the base plate, so that in a first position the toggle switch completes an electrical switching circuit and in a second position the toggle switch 2() breaks the electrical circuit, this electrical circuit further comprising a dimmer circuit comprising an adjustable resistor and a manually displaceable actuator member for effecting adjustment of the variable resistor, wherein the manually displaceable actuator comprises a rotatable member mounted concentric with and rotatable about the toggle axis. Preferably, the rotatable member will comprise a bezel of such electrical switch and will preferably comprise a cylindrical or domed structure of the type seen in traditional Victorian and Edwardian lighting circuits.

The rotatable member may also comprise an appropriate surface decoration. s

Preferably, the variable resistor will comprise a rheostat wherein the electrical switch will further comprise a gear mechanism disposed between the rotatable member and this rheostat. This gear mechanism will usually comprise an appropriate wheel mounted on a further axis extending parallel to the toggle axis 1() and may, in fact, comprise a plurality of rotatable wheels. Such wheels may employ toothed engagement between the rheostat, or other adjustable resistor, and the rotatable member or may rely on frictional engagement therebetween. in either case, the gear mechanism would preferably be constructed from an electrically insulating material, such as plastic or rubber to prevent any electrical discharge between the switching circuit and the rotatable member which is for manual operation by an end user. Alternatively, or in combination, the rotatable member itself may also be constructed of an electrically insulating material (such as bakelite) or may comprise a metallic surface mounted on an electrically insulated material so as to insulate the end user from the switching circuit.

There will now be described, by way of example only, a preferred embodiment of the present invention in which: s Figure 1 is a front elevation of an adjustable electrical switch according to the present invention; and Figure 2 is a schematic cross sectional view along the lines 11-ll of the switch of Figure 1; and Figure 2a is a cross sectional view of a conventional switching mechanism of a toggle switch; and Figure 2b is a plan view of a slideable switch member of the switching mechanism of Figure 2a, and Figure 3 is a circuit diagram of the adjustable switch of Figure 1.

lS Referring now to Figure 1, there is shown a traditional period lighting control switch (10) comprising a substantially square wooden pattress (12) (such pattress forming a backing plate of the switch) on which is mounted a conventional toggle switch (14) and about such toggle switch (14) is concentrically mounted a brass domed bezel (1f,) (Figure 2) . The aesthetic appearance of such a lighting control switch (1()) is very traditional, dating back over 100 years.

The operation of this type of traditional lighting switch is well known in the art and need not be described in any great detail, save to explain that the toggle switch (14) is displaceable from a first operative position (usually an upper position as shown in Figure I) to a second operable position (shown in hashed lines in Figure 2) where an appropriate mechanism is used to bias the toggle switch into one of these two actuated positions. These actuated positions S represent end stop positions allowing the toggle switch to be snap displaced between the two. This provides a switch having a tactile indication of the on/off positions. The switch is predominantly used in lighting circuits utilising an AC power source, whereby a first actuated position (Figure 1) the switch element serves to break the electrical switching circuit, whereas displacement of the toggle switch to its second actuated end stop position serves to complete the lighting circuit, allowing power to be transferred from the power source to the load (usually a light bulb).

Whilst of a traditional aesthetic design, this particular type of light switch (10), having a domed bezel, is currently very popular in the field of interior design and considered essential in maintaining appropriate design continuity where traditional internal decor is required.

Referring now to Figure 2, the bezel (16) can be seen to be substantially hollow 2() forming a domed shell concentrically surrounding the toggle switch (14). In Figure 2, the switching circuit to which the toggle switch actuator is operatively connected is simply shown schematically as box 18. However, it will be appreciated that the actual construction and operation of the toggle switch and specifically the switching circuit controlled by such toggle switch (14) as it is displaced between its first and second actuated positions, are well known and commonplace within the art. The specific invention is not limited to any specific type of toggle switch arrangement or switching circuit and is thus represented schematically in Figure 2. Here it can be seen that the switching mechanism (18) can be partially housed within the hollow domed bezel (16) and also within a recess formed within the pattress. However, it is also possible that the switching circuit may be simply mounted on a surface of the pattress within the domed bezel, or the pattress may be designed so as to be compatible with modern switch boxes so that the switching circuit can be recessed within such a switch box housed within a wall cavity, with communication provided from the toggle switch (14) thereto through an appropriate aperture formed in the pattress (12).

Figures 2a and 2b provide an illustrative example of one possible switching mechanism compatible with toggle switches but is simply provided by way of example only and may be replaced by any other type of conventional toggle switch operated switching mechanism. Figure 2a represents a cross section through the toggle switch (14) in an appropriate switching circuit (100).

Essentially, the toggle switch (14) comprises a lever arm (102) extending radially from a spherical solid ball member (104). The ball member (1()4) is restrained from relative displacement within the electrical switch (10) by co-operating engagement with two concave support faces (106) which are concentric about the centre (108) of the ball member (1()4). These support faces (106) restrain the toggle switch (14) in the electrical switch, but permit pivotal displacement of the toggle switch (14). Diametrically opposed to the lever (1()2) is a switch actuator (11()) which is received within an elongate slot (112) of an electrically insulated switch member (114). This switch member may be of a traditional material such as porcelain or replaced by a modern material such as plastic. The switch member (114) is restrained within the electrical switch so as to be slideable in a direction parallel to its longitudinal length (arrow 71) and restrained from displacement in a transverse direction thereto. Since the switch actuator (110) of the toggle switch (14) is retained within the elongate slot (112) it can thus effect appropriate longitudinal displacement of the switch member (114) but is restrained from transverse displacement relative thereto. This ensures that whilst the toggle switch (14) is pivotal about its centre point (108) between the two support walls (106), such pivotal displacement is restricted to a plane (90) (Figure 1), perpendicular to and parallel with the direction of movement of the switch actuator (114). Furthermore, this switching element (114) is provided with two end stop positions defining the pivotal limitation of the toggle switch (14) between two extreme positions. Additionally, the switching circuit (118) is also provided with an appropriate leaf spring member (12()) which is engageable with and biases the switch actuator (110) to one of its two extreme positions, as illustrated in Figure 2a. Operation of the toggle switch (14) will incur an appropriate resistive force exerted by this leaf spring member in movement from one extreme position to the other and which leaf spring member serves to retain the toggle switch in one of its two actuated positions as is conventional. As will be understood from Figure 2a, as the toggle switch is pivotally displaced from one position to the other, engagement between the switch actuator ( l 1()) and the switch member (114) through the slot (112) will effect longitudinal displacement of the switch member from one actuated position to a second actuated position. An electrically conductive strip (122) is mounted on the insulated switch member (114) in a position so as to remain remote from the conductive toggle switch (14), and which is maintained in electrical contact with a first electrical terminal (124) which is connected to an appropriate live connection (L) of an AC circuit. A second electrical terminal (126) is then connected as an output from this basic switching circuit. In the position in Figure 2 and Figure 2a, the toggle switch (14) is displaced so as to maintain the switching member (114) disposed in a first actuated position whereby the electrical conductor (122) is restrained from completing an electrical connection between the two terminals (124) and (126).

Subsequently, when the toggle switch (14) is displaced to its second actuated position (as shown as hashed lines in Figure 2) this will subsequently effect displacement of the switch member (114) from right to left as viewed in Figure 2a so as to bring the conductive member (122) into electrical contact with the terminal (126) thus completing the switching circuit.

The toggle switch (14), through the switching mechanism (IS) is thus able to effect electrical connection (via an appropriate electrical connector or lead shown schematically as (19) in Figure 2) between a live connection (L) and a conventional dimmer circuit (20), (again shown schematically as a box in Figure 2). The design and construction of dimmer circuits is well known within the art, one example of which is described in UK Patent No. 2289165. The dimmer control circuit employed in the current embodiment is illustrated in Figure 3 and designed for use with AC power sources. Such dimmer control circuits comprise an adjustable or variable resistor PPl (which in this embodiment comprises a rheostat). The lighting control circuit of the current invention utilises a toggle switch (14) to connect the dimmer control circuit (20) between an earthed and live (L) connection (as shown in Figure 3), to provide a live connection (L) of an AC mains supply to a load (in this example a light (3())) which is conventionally connected to the neutral connection of the AC mains supply. The dimmer circuit (20) is a conventional design comprising three capacitors C1, C2 and C3, two fixed resistors R1, R2 and appropriate toroidal winding TCI, together with a triac TRl and a diac Dl. As is well understood in the art, for a circuit of this design the variable resistance PP1 will control the firing angle of the triac TR1 via the diac Dl so that the triac TRI, in series with the toroidal winding TC1, controls the current drawn by the load (lamp (30)), so as to control the brightness of the lamp.

Thus, the lamp (30) is brighter when the triac conducts for more of the AC cycle and is subsequently dimmer when the triac conducts less of the AC cycle. If so required, the circuit design can be established so that the range of the variable resistor PP1 can be sufficient to prevent triac TRl from firing at all at an extreme position so as to effectively act as a second "off" switch.

Referring now to Figure 3, the variable resistor in this embodiment is a rheostat which is rotatably operated by a rotatable spindle (26) which spindle is rotatable about an axis A1 (Figure 2) extending substantially perpendicular to the pattress (12).

The bezel (16) is mounted on the pattress (12) so as to be rotatable about a toggle axis A2 (Figure 2) which extends perpendicular to the pattress (12) through the centre of the ball portion (104) of the toggle switch (14) and about which toggle axis the toggle switch (14) is able to be displaced between the two extreme 1() actuated positions (as indicated by arrow 32). The axis A2 extends in a plane through which the toggle switch (14) is able to be displaced between the two actuated positions and intersects the pivot point (40) of this toggle switch, representing the centre of the electrical switch (10). In this manner, it would be appreciated that the bezel (16) is concentric about the toggle switch (14) as shown in Figures 1 and 2.

In this embodiment, the bezel (16) is mounted on the pattress so as to be restrained in rotatable engagement therewith about this toggle axis A2. Although not shown in detail in the current figures the means for providing restrained rotational 2() engagement of the bezel (:16) with the pattress (12) can be achieved by a number of mechanisms. In one embodiment (not shown), the bezel (16) could be retained on an appropriate screw threaded spindle for screw threaded rotation thereabouts to effect rotational displacement whilst being retained in engagement with the pattress, such screw threaded engagement being effected between the internal perimeter wall (44) of the domed bezel (16) and a complimentary screw threaded projection extending perpendicular from the pattress (12) and again concentric about the toggle axis A2. Alternatively, the bezel (16) could be provided with an appropriate inner lip (shown schematically as (50) in Figure 2) forming a concentric inner rim on the internal surface of the domed bezel for complimentary snap engagement with a continuous (or plurality of individual) resiliently biased shoulder members (52) extending from the surface of the pattress (12). The various means of securing the bezel (16) for such rotary engagement are numerous and the above are provided by way of example only. The important feature being that the bezel (16) is maintained in close proximity to the pattress (12) but freely rotatable through at least an angular range of 90 about the toggle axis A2.

An appropriate gear wheel (60) is rotatably mounted on the pattress (12) by a spindle member (16) so as to be rotatable about a spindle axis A3, which axis A3 again extending parallel to axis A1 and A2. This gear wheel (60) is provided with a diameter equivalent to the lateral distance between the internal perimeter wall (44) of the bezel (16) and the spindle (26) of the rheostat (adjustable resistor).

The axis A3 is disposed equidistant between the axis A1 and the inner perimeter wall diameter of the bezel (16). This gear wheel (60) is then positioned in driving engagement with both the bezel (16) and the spindle (26). Such engagement is provided by one of several possible means and in this particular embodiment, the drive wheel (60) is provided of a resilient rubberised material which frictionally engages both the bezel (16) and spindle (26) whereby such frictional engagement results in rotational displacement of the bezel (16) about axis A2 being transmitted to rotational displacement of the gear wheel (6()) about axis AS in a same rotational direction, whereby the rotation of the gear wheel (6()), through frictional engagement with the spindle (26), effects subsequent rotational displacement of such spindle (26) about axis A1 in a rotational direction opposed to the rotational direction of the bezel (16) and gear wheel (60) (as indicated by arrows 71, 72 and 73 respectively in Figure 2). For clarity the gear wheel (60) is shown schematically in hashed lines in Figure 1 as is the drive spindle (26), illustrating the rotational relationship between the bezel (16), gear wheel (60) and spindle (26). Again, directional arrows 71, 72 and 73 illustrate the relative rotational displacement of these three rotary members. If the direction of the rotation of the bezel (16) is reversed to the direction (71) shown then effectively the rotational direction (72) of the gear wheel (6()) and subsequent rotation (73) of the spindle (26) will also be reversed. In this way, rotation of the bezel (16) is transmitted, through the gear wheel (6()) to effect rotational adjustment of the rheostat PP1 of the circuit shown in Figure 3 so as to effect operation of a conventional dimmer circuit.

This preferred embodiment of the invention thus provides a traditional aesthetic appearing light switch utilising an on/off toggle switch but further enhanced by utilization of the bezel (16) to effect operation of a conventional dimmer circuit Whilst this preferred embodiment utilises a dimmer circuit for use with AC power source and for operation of a light bulb, it will be appreciated that it is equally applicable to vary the power transfer between a power source and any electrical load so as to provide controlled operation of that load. Furthermore, the invention is equally applicable to a light switch for controlling power transfer between a DC power source and a load by use of an appropriate alternative dimmer circuit applicable for a DC power source. This will involve a more simplified system usually only necessitating use of the adjustable resistor to control the power between the DC power source and the load.

In the current embodiment, the bezel (16) is made of brass, an electrically conductive material, as is the toggle switch (14). However, as is conventional for switches of this type, the toggle switch (14) is appropriately insulated from the electrical connectors of the switch mechanism (18) so as to reduce the possibility of electric shock to the user. Since the bezel (16) is now used to operate a further switching mechanism of the dimmer circuit, the risk of electric shock is again minimised by utilization of an appropriate insulating material, such as rubber or plastic, to form the gear wheel (60). This material thus serves a dual purpose of providing appropriate electrical insulation whilst also providing appropriate 2() frictional coefficient to enable co-operative engagement between the bezel (16) and the gear wheel (60).

Alternatively, the bezel (16) could be made of an insulating material such as bakelite which is again traditional in light switch designs of this type. Still further, where metal bezels arc required (such as brass, or plated bezels such as chrome or nickel), the interior surface could be appropriately insulated by rubber, plastic or other insulating material. Such a coating is again beneficial as also having a higher frictional coefficient than the metal or brass used in the current embodiment and again enhances the frictional engagement between the bezel and the gear wheel (60).

Further variants of the present invention are also envisaged whereby more than one gear wheel can, if required, be disposed between the bezel and the spindle (26). By careful selection of the or the plurality of gear wheels, then greater control over the rheostat can be achieved to preset requirements. Dependent on the various gear ratios between the spindle diameter, the gear wheel diameter or the number of gear wheels used, the amount of adjustment of the rheostat per degree of rotation of the bezel (16) can be altered so as to achieve more sensitive or coarser control of the dimmer circuit. In this way, the switch could be designed so as to permit rotation of the bezel only through a predetermined angular range sufficient to vary the rheostat from a minimum to maximum value, or alternatively, this gear mechanism can be adjusted so that rotation of the bezel through 36() is required to effect a full range adjustment to the rheostat.

Furthermore, whilst the current embodiment utilises a rotary gear mechanism to effect adjustment of a rheostat, other forms of actuation of an adjustable resistor can be employed. For example, the rheostat may be replaced by conventional potentiometer requiring linear adjustment of such a variable resistor. Here the gear wheel (60) could simply engage a linearly displaceable actuator to vary the potentiometer value. Still further, if required the gear wheel (60) could be simply omitted and the bezel (16) disposed in direct engagement with a spindle (26) of a rheostat. Here the wall thickness of the bezel (16) could be adjusted so that it directly engages the spindle (26) in the position shown in Figure 1 or alternatively the rheostat and the spindle (26) could be moved radially away from the toggle axis A2 and into abutment with the internal surface of the bezel wall (44).

Still further, whilst the embodiment shown in Figure I uses a conventional toggle switch, the term toggle switch is intended to cover any pivotally displaceable switch member displaceable from a first actuated position to a second actuated position and will further comprise conventional rocker switches which again can be disposed about a toggle axis A2 about which an appropriate cylindrical or domed bezel (16) can be mounted for rotatable displacement.

2() The present invention provides considerable advantages over existing combined on/off and dimmer switches. Specifically, the use of a toggle switch operable between two definitive actuated positions allows the user to identify, through tactile feedback, that the switch has been operated from one mode to the other.

Secondly, by utilising the bezel as an actuator for the dimmer circuit provides an actuator having a greater size and diameter in comparison to existing dimmer switches utilising a rotatable knob, which knobs have diameter of 2cm or less.

Such a larger rotational member provides for ease of operation particularly for those with disability involving loss of function of their hands. This is achieved without detriment to the aesthetic appearance of such traditional light switches.

A further advantage of the present invention is that, due to its simplistic design, the invention is readily incorporated into existing lighting control switches having such domed or cylindrical bezels without detrimental effect to the visual appearance of such switches.

Whilst the preferred embodiment herein described utilises a wooden pattress, the invention is not so limited but could include any insulating material to form the pattress such as bakelite (again utilising traditional materials and design) or modern plastic if so required. Similarly, whilst the bezel is described as domed, the term "domed" or cylindrical when used in relation to the bezel is meant to indicate a bezel having a substantially circular perimeter to be mounted concentrically about the toggle switch and having a substantially hollow interior.

Thus, the cross section of the profile of the bezel need not be smooth as in the domed embodiment herein described, but could be faceted, stepped or any number of plurality of shapes provided it is substantially hollow so as to accommodate appropriate dimmer circuits and lighting circuits and can be mounted so as to be rotatable about the toggle axis of the toggle switch.

Additionally, where the gear wheel mechanism of the present embodiment is utilised to effect displacement of the adjustable resistor (rheostat), then the interior surface ol' the bezel will need to be circular and concentric about the toggle switch axis. However, it is also envisaged that alternative means for effecting adjustment of the resistor dependent on rotational movement of the bezel can be effected.

One alternative variant of the present invention can simply utilise a lever arrangement connecting the bezel and the adjustable resistor so that adjustment of the bezel is transferred through such lever to vary the adjustable resistor. The key feature here being an appropriate connecting mechanism to allow movement of the bezel to be translated to movement and hence adjustment of an adjustable resistor such as a rheostat. In such an embodiment, the lever may be slideably received within the rotatablespindle of the rheostat so as to accommodate any lateral displacement of this lever towards the rheostat during rotational displacement of the bezel. 2()

Claims (9)

1. Claims 1. An adjustable electrical switch for varying the power transfer

   between a power source and a load, comprising a base plate having a toggle switch mounted thereon and pivotally displaceable between a first and second operative position about a toggle axis extending perpendicular to said base plate so that in a first position said toggle switch completes an electrical switching circuit and in a second position said toggle switch breaks said electrical circuit, said electrical circuit further comprising a dimmer circuit comprising an adjustable resistor and a manually displaceable actuator member for effecting adjustment of said variable resistor, wherein said manually displaceable actuator comprises a rotatable member mounted concentric with and rotatable about said toggle axis.
2. 2. An electrical switch as claimed in claim 1 wherein said rotatable member comprises a bezel.
3. 3. An electrical switch as claimed in either of the preceding claims in which said 2() rotatable member is cylindrical or domed.
4. 4. An electrical switch as claimed in any one of the preceding claims wherein said variable resistor comprises a rheostat.
5. 5. An electrical switch as claimed in any one of the preceding claims and further comprising a gear mechanism disposed between said adjustable resistor.
6. 6. An electrical switch as claimed in claim 5 wherein said gear mechanism comprises a wheel mounted on an axis extending parallel to said toggle axis.
7. 7. An electrical switch as claimed in claim 5 or claim 6 wherein said gear mechanism is constructed from an electrically insulating material. 1()
8. 8. An electrical switch as claimed in any one of the preceding claims wherein said rotatable member is constructed of an electrically insulating material.
9. 9. An electrical switch substantially as herein described with reference to the accompanying illustrative drawings.