This invention relates to electric switches, particularly to remote control electric switches.

Remote control switches are, of course, well known and include such devices as remote controllers for television and audio equipment, and keys for automobile doors and alarm systems. Also available are portable switches for interior lighting. These devices can operate in one of a number of ways, as by infra red, ultra¬ sound or radio emission, detected at the lamp or other appliance to be controlled by a suitable receiver. The transmitter part of the arrangement is powered by a battery.

Batteries nowadays have a reasonable life, and the small amount of energy used in each transmission requires a battery change usually after a period of a year or even more. However, batteries are not inexpensive even though they may need only infrequent replacement, and replacement batteries may not be to hand when battery failure occurs, rendering the remote controller and, if no alternative control is available (as in a ceiling light, for example) the controlled device inoperable until a replacement is purchased and fitted.

The present invention provides switches that do not require battery replacement.

The invention comprises a remote control electric switch arrangement comprising a transmitter and a receiver, in which the transmitter comprises power means for producing or converting power for transmission from an external energy source.

The power means may convert mechanical energy into electrical energy, and may comprise a vibrator moving a magnet with respect to a coil. The vibrator may

comprise a spring, which may be a leaf spring, and may comprise means causing the spring to vibrate. Such means may comprise a toggle, which may comprise magnetic spring contacting and releasing means, and which may be constructed and arranged with similar form and operation to a conventional electric switch.

The transmitter may transmit a coded signal to which the receiver responds. The arrangement may comprise a vibrator generating an a.c. electrical output, and comprise circuitry generating output signal pulses forming a codable pulse train and further comprise coding means selecting which pulses of the train are output as signal to the receiver.

The arrangement may be adapted as a control for an electrical appliance. The receiver may be comprised in the appliance and/or powered from the power source for the appliance. The control may be a simple switch or a more comprehensive control such as a level controller, e.g. a dimmer for an electric lamp, which may comprise switch means selectively driving a motorised rheostat up or down.

The transmitter may be comprised in a wall mount, which may be fashioned like a conventional electric wall switch, and, indeed, mounted to all intents and purposes as a conventional wall switch would be mounted, but without the need of wiring connecting it between a power supply - the building mains supply - and the appliance. This greatly facilitates electrical installation, especially when new lighting or other appliances are being fitted to an existing building, which fitting can be readily effected without any disruption to the walls or even to the decoration.

The transmitter (or another transmitter) may be comprised in a portable unit, which may be adapted for carrying in the pocket or for setting down on a table top.

The transmitter may be a radio transmitter, although, of course, it could be an ultra-sound or infra-red or other transmitter.

The transmitter may, in other arrangements, comprise a power receiver for radiation transmitted from the receiver and which converts it to transmittable energy. The transmitter may comprise an energy accumulator which accumulates energy transmitted from the receiver over a period of time and dissipates some or all of the accumulated energy when actuated. The transmitter may, however, simply reflect power transmitted to it by the receiver and be actuated by interrupting such reflection.

Embodiments of remote control electric switch arrangements according to the invention will now be described with reference to the accompanying drawings, in which:-

Figure 1 is a perspective view of a transmitter of a first arrangement;

Figure 2 is a diagrammatic representation of a receiver of said first arrangement;

Figure 3 is a typical pulse sequence of a switching signal;

Figure 4 is a diagrammatic representation of a second, level control arrangement;

Figure 5 is a diagrammatic representation of a third arrangement;

and Figure 6 is a diagrammatic representation of a further arrangement.

The drawings illustrate remote control electric switch arrangements comprising a transmitter 11 and a receiver 12, in which the transmitter 11 comprises power means 13 for producing or converting power for transmission from an external energy source.

Figure 1 illustrates an arrangement in which the power means 13 convert mechanical energy from the manual actuation of a switch member 14 into electrical energy. The power means 13 comprise vibrator means 15 moving magnets 16 with respect to coils 17.

The vibrator means 15 comprise two springs, in particular leaf springs, held on a mount 18. The magnets 16 (particularly when the arrangement is comprised in a small unit, the size of a conventional light switch) are strong permanent magnets such as rare earth magnets. Vibration of either magnet 16 with respect to its coil 17 gives rise to an alternating electrical output current at the coil terminals which is used, in this embodiment, to power the switching signal emitted from the transmitter circuit 19 of the transmitter 11.

The switch member 14 - which is like that of a conventional wall light switch has magnets 14a. When the switch member 14 is toggled, it pulls the leaf spring 15 to which it is attached towards its associated coil 17 and eventually releases it to vibrate freely, except insofar as its vibration decays due to conversion of its vibrational energy into electrical energy by the interaction of the coil and magnet.

The two coils 17 could in some instances be replaced by a single coil, for example where switch position identification is not required.

The vibration of the magnet 16 in the coil 17 gives rise to a sinusoidal output at the coil terminals. This sinusoidal output is converted in a signal processing

circuit 21 to a square wave form of which, say, the first eight cycles are selected as a coding sequence, as shown in Figure 3. Given that pulse number 1 is a start-sequence pulse, and pulse number 8 is an end-sequence pulse, there are 2 ⁶ possible sequences, or 64. The processing circuit 21 codes the pulse sequence by selecting or deselecting pulses between the first and last of eight so as to transmit a radio signal which can be unique to the arrangement so far as concerns like arrangements as may be located within range so as to avoid spurious operation.

Figure 2 illustrates a receiver 12 of said first arrangement. It comprises a radio receiver 22 receiving the radio transmission from the transmitter 1 1 and, after, amplification, passing the signal to a discriminator 23 which has a switching output if the signal corresponds to a stored pulse sequence, not if it doesn't. The switching output actuates a switch 24 for a lamp 25. The receiver 22 and discriminator 23 are each powered from the same source as the lamp 25, namely, for example, a domestic, office or industrial mains power circuit.

Figures 1 to 3 illustrate a simple on/off switching arrangement suitable for use as a light switch. Sometimes it is desired to effect a more sophisticated control, for example a dimming control. Figure 4 illustrates a suitable arrangement in which the transmitter 11 has a bipolar switch 41 which powers it via a code selector circuit 42 to transmit different codes for increase and decrease. The coded signals are received by the receiver 12 and fed to a control circuit 43 which outputs signals powering a motorised rheostat 45 in opposite directions to dim the lamp 44.

These switches can be installed in bathrooms and the like where conventional switches are not permitted, there being no danger of electric shock.

Figure 5 illustrates an arrangement in which the transmitter 11 itself receives power from the receiver 12 which comprises a power transmitter 51 transmitting

radiation, e.g. by induction to the transmitter 11 which has an energy store 52 in which the energy is accumulated. The energy transmitted by the power transmitter is stored in the store 52 until utilised by the transmitter 1 1.

Figure 6 illustrates an arrangement in which radio, infra-red or other power from the appliance 61 is beamed to the transmitter 11 - in this case a wall mounted device comprising a reflector 62 reflecting the same back to the appliance 61. Switching is effected simply by interrupting the beams, when the receiver 12 at the appliance 61 is actuated for a switching operation.

In yet other arrangements, ambient vibration can be used to power a transmitter. In automobiles, for example, remote control switches could be installed without connection to the accumulator or to the device or appliance to be switched or controlled that derive their power from vibrations which inevitably occur at the switch position when the engine is running. It is possible to operate such switches by arresting or damping and releasing from arrest or damping a vibrating spring.

It will be appreciated that it is not intended to limit the invention to the above examples only, many variations being possible without departing from the scope thereof as defined by the appended claims.

Thus, although simple one-way switches have been described, the invention may be applied to two-way switches or indeed any other conventional kind of switch.

The transmitter may communicate with the receiver through wires and although at first sight this may appear self-defeating, it would enable conventional switches to be replaced with those of the invention (which do not cause any arcing) to advantage in hazardous environments.