TECHNICAL FIELD The present invention relates to the field of switches, especially light fixtures.

BACKGROUND ART A common type of light fixture switching system comprises two separate switches, each disposed in different locations in the same room. In such a switching system, a user may turn on a light fixture from one switch, and turn off the light fixture by the other switch. As such, this kind of domestic switching allows a user to turn on the light fixture in his bedroom, to approach his bed, and while he is near to his bed, to turn off the light fixture by the other switch.

One drawback in this type of switching is that it is a sophisticated system which requires a technician to install it, and the installation time is relatively long. In addition, using this kind of switch, the user still has to pass through the dark from the switch location in the room, to his bed.

Another type of light fixture switch, which is used in stairways and corridors, employs a delay. According to this kind of switch, there is no off state! after turning the light on, it stays lit for a period of minutes, and then turns off. For example, after a user turns on a stairway light fixture, the light fixture continues to light for a predefined period, and then turns off automatically. During this period, a user has time to reach from the elevator to his apartment door, to unlock his door, and to enter into his flat.

In this kind of switch, the delay period is determined by simple electronic components, such as capacitor and resistor. In this way, two objects are achieved: simplicity of the switch device, and reducing the number of moving parts, such as a potentiometer. As such, a major drawback in this kind of switch is that the delay period cannot be adjusted to the special requirements of each case. It is an object of the present invention to provide a solution to the above-mentioned and other problems of the prior art.

Other objects and advantages of the invention will become apparent as the description proceeds.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to an on- off switch (10, 10'), comprising:

- an on state (illustrated in Fig. 4a), being a state in which power is supplied to a power consumer!

- a delayed off state (illustrated in Fig. 4c), in which power is stopped from being supplied to the power consumer after a predefined period from turning the switch to the delayed off state, rather than immediately.

The switch may further comprise an immediate off state (4b), in which power is stopped from being supplied to the power consumer at once.

According to one embodiment of the invention, turning the switch from one state to another state is carried out by a button (12), activated by a user's hand (18). The switch may further comprise an indicator (16), for indicating that the switch has been turned to the delayed off state, but power is still supplied to the power consumer for a predetermined period. According to one embodiment of the invention, the switch comprises a spring (20) for turning the button (12) from the delayed off state (illustrated in Fig. 4c) to the immediate off state (illustrated in Fig. 4b), upon releasing the button (12) by the user's hand (18). According to one embodiment of the invention, the switch employs an electronic circuit, comprising:

- a capacitor (47μΡ/25ν) chargeable when the switch is in the on state!

- a resistor (80ΚΩ), for determining along with the capacitor (47μΡ/25ν) the predetermined period (i.e., delay period);

- a relay, for connecting / disconnecting power supply to the power consumer (such as the lamp in Fig. 5);

- a transistor, for increasing a current reaching to the relay when the capacitor (47μΡ/25ν) is being charged; thereby as long as the capacitor is being discharged, the transistor is switching a current reaching the relay, resulting in retaining closed a circuit providing power to the power consumer, and vice versa.

According to one embodiment of the invention, the resistor is of a potentiometer, thereby allowing a user to adjust the predetermined period (i.e., the delay period).

According to one embodiment of the invention, the switch is implemented in a bedroom light fixture. According to another embodiment of the invention, the switch is implemented in a stairway.

According to another embodiment of the invention, the switch employs an electronic circuit comprises : ^■ a capacitor chargeable when the switch is in the on state!

^■ a resistor, connected in parallel with a diode bridge!

^■ an electromagnetic relay, for connecting / disconnecting power supply to the power consumer!

thereby, as long as the capacitor is being discharged, the electromagnetic relay is switching a circuit, resulting in providing power to the power consumer. According to yet another embodiment of the invention,

The electronic circuit is capable of receiving a low voltage (for example 12V) from a power supply (110V - 220V), comprises a resistor connected in parallel with a diode bridge, the diode bridge provides a direct current for a delaying mechanism, the delaying mechanism comprising a capacitor connected in parallel with an electromagnetic relay, wherein the relay is switching the circuit providing power to the power consumer.

The reference numbers have been used to point out elements in the embodiments described and illustrated herein, in order to facilitate the understanding of the invention. They are meant to be merely illustrative, and not limiting. Also, the foregoing embodiments of the invention have been described and illustrated in conjunction with systems and methods thereof, which are meant to be merely illustrative, and not limiting. BRIEF DESCRIPTION OF DRAWINGS

Preferred embodiments, features, aspects and advantages of the present invention are described herein in conjunction with the following drawings :

Each of Figs. 1 and 2 is a side view which schematically illustrates an on-off switch 10, according to one embodiment of the invention.

Fig. 3 pictorially illustrates a three-state on-off switch 10', according to one embodiment of the invention.

Each of Figs. 4a, 4b and 4c is a sectional view on the switch of Fig. 3. Fig. 4a illustrates the switch in its on state! Fig. 4b illustrates the switch in its immediate turn off state! and Fig. 4c illustrates the switch in its delayed turn off state thereof. Each of Figs. 5 and 6 is a scheme of an electronic circuit for the three-state on-off switch 10' illustrated in Figs . 3, 4a, 4b and 4c, according to one embodiment of the invention.

It should be understood that the drawings are not necessarily drawn to scale. DESCRIPTION OF EMBODIMENTS

The present invention will be understood from the following detailed description of preferred embodiments ("best mode"), which are meant to be descriptive and not limiting. For the sake of brevity, some well-known features, methods, systems, procedures, components, circuits, and so on, are not described in detail. Each of Figs. 1 and 2 is a side view which schematically illustrates an on-off switch 10, according to one embodiment of the invention. Fig. 1 illustrates the switch in an on state, thereof while Fig. 2 illustrates the switch in the delayed turn off state thereof.

In order to turn on the switch, the user has to press the upper side of button 12; and in order to turn off the switch, the user has to press the lower side of button 12. The difference between a prior art switch and the switch illustrated in these figures is that upon turning off the button 12, the switch does not turn off immediately, but rather after a delay. For example, assuming a user is in a windowless room, and switch 10 is installed away from his bed, when turning off the switch, the light will not turn off immediately, but rather after a few seconds, which will give him enough time to reach his bed. In comparison, in such a situation a prior art switch will cause the user to walk to his bed in a dark room. However, a switch according to the present invention allows the user to walk into a lighted room. Fig. 3 pictorially illustrates a three-state on-off switch

10', according to one embodiment of the invention.

Reference numeral 16 denotes an indicator, such as a LED (Light Emission Diode), for indicating that the button to turn the power supply off has been activated, but the power is still supplied for a predetermined period.

The LED may be designed to blink in its on state, in order to attract the user's attention.

Each of Figs. 4a, 4b and 4c is a sectional view of the switch of Fig. 3. Fig. 4a illustrates the switch in its on state! Fig. 4b illustrates the switch in its immediate turn off state! and Fig. 4c illustrates the switch in its delayed turn off state thereof.

As per the mechanical structure, in each state of button 12, track 32 is shifted to another position. In Fig. 4a, the track is shifted down, in Fig. 4c the track is shifted up, and in Fig. 4b the track is shifted to a middle position between the up and down positions.

Spring 20 is used to return button 20 from the situation illustrated in Fig. 4c to the situation illustrated in Fig. 4b. In other words, after a user turns the button to the DELAYED- OFF state illustrated in Fig. 4c, upon releasing the button, it returns to the OFF state, which is the situation illustrated in Fig. 4b.

The switch employs three contacts, 28, 26 and 30, and a conductive element 34 attached to track 32.

In the on state illustrated in Fig. 4a, contacts 26 and 30 are connected by element 34; in the delayed off stated illustrated in Fig. 4c, contacts 26 and 28 are connected by element 34; and in the off state illustrated in Fig. 3b, these contacts are not connected by a conductive element. Fig. 5 is a scheme of an electronic circuit for the three- state on-off switch 10' illustrated in Figs . 3, 4a, 4b and 4c, according to one embodiment of the invention.

The 0.44 μΈ capacitor and the 820ΚΩ resistor which are connected to the phase entry, lower the voltage from 220V to 26V.

The four diodes are a diode -bridge which converts the alternating current to direct current.

Since the current is alternate, capacitor 10μΡ/50ν is used as an averaging mechanism, i.e., for straightening the current signal. The object of the ΙΚΩ/IW resistor is to generate a constant load on the power source in order to prevent the load from being increased and thereby damaging the electronic components of the circuit when the electronic circuit is in an idle state thereof, i.e., it does not consume power.

When the "springy switch" (illustrated in Figs. 4a, 4b and 4c) gets power, even for a moment, the 47μΡ/25ν capacitor is charged. Upon ceasing the power supply (as a result of a switching off), the capacitor is discharged. The discharging time of the capacitor depends on its capacity and on the resistance of the resistor (80ΚΩ). As the resistance is decreased, the discharging time (i.e., the delay period) is decreased, and vice versa.

As long as the capacitor is discharging, the transistor is switching the current reaching the relay, and retains closed the circuit that provides power to the lamp, i.e., the lamp lights. Upon discharging the capacitor from its charge, the power supply to the relay ceases, and therefore no power reaches the lamp.

The 80ΚΩ resistor can be replaced by a potentiometer, thereby allowing a user to adjust the discharging time, i.e., the delay period.

Fig. 6 is a scheme of an electronic circuit for the three- state on-off switch 10' illustrated in Figs . 3, 4a, 4b and 4c, according to another embodiment of the invention. According to this embodiment of the invention, the electronic circuit comprises: a capacitor chargeable when the switch is in its on state! a resistor, connected in parallel with a diode bridge! an electromagnetic relay, for connecting / disconnecting power supply to said power consumer! thereby, as long as the capacitor is being discharged, the electromagnetic relay is switching a circuit, resulting in providing power to the power consumer. The electronic circuit is capable of receiving a low voltage (for example 12V) from a power supply (110V - 220V). The electronic circuit comprises a resistor connected in parallel to a diode bridge providing a direct current for a delaying mechanism. The delaying mechanism comprises a capacitor connected in parallel with an electromagnetic relay for switching the circuit that provides power to said power consumer.

In the figures and/or description herein, the following reference numerals (Reference Signs List) have been mentioned:

- numeral 10 denotes a two-state on-off switch, according to one embodiment of the invention!

■ numeral 10' denotes a three-state on-off switch device, according to one embodiment of the invention!

- numeral 12 denotes an on-off button!

- numeral 14 denotes a frame of an on-off switch!

- numeral 16 denotes a delay indicator! - numeral 18 denotes a user's hand;

- numeral 20 denotes a spring!

- numeral 26 denotes a contact;

- numeral 28 denotes another contact;

■ numeral 30 denotes a third contact;

- numeral 32 denotes a track; and

- numeral 34 denotes a conductive element.

The foregoing description and illustrations of the embodiments of the invention has been presented for the purposes of illustration. It is not intended to be exhaustive or to limit the invention to the above description in any form.

Any term that has been defined above and used in the claims, should to be interpreted according to this definition.

The reference numbers in the claims are not a part of the claims, but rather used for facilitating the reading thereof. These reference numbers should not be interpreted as limiting the claims in any form.