Patent Application
20060232333
The present patent application claims priority from Italian Patent Application No. MI2005A 000521, filed on Mar. 30, 2005.
The present invention relates to a device for connecting electric household appliances to an electric power main.
As is known, many currently marketed electric household appliances are designed to remain in an energy-saving or standby configuration when not in use. In this configuration, the appliance is still powered, but the electricity drawn from the mains is reduced to the absolute minimum necessary to restore normal operation rapidly when required. Most remote-controlled appliances, for example, such as televisions or stereo systems, have a standby configuration, so they can be turned back on using the remote control, as opposed to manually reconnecting the appliance to the mains using the on/off switch.
In the standby configuration, the appliance must still be connected permanently to the electric power main, which poses serious drawbacks, also in view of the fact that most appliances are left in the energy-saving configuration for many consecutive hours a day and very often unattended. In particular, the appliance is exposed to mains surge caused, for example, by malfunctions or lightning; and wear or faults in continuously powered component parts of the appliance may cause serious damage, or even fires, as a result of overheating. Apart from the safety aspect, another important point to bear in mind is that, though reduced, power draw in the standby configuration is not nil, and often amounts to a few tens of watts. And, since most homes normally have numerous electric appliances, which may be left in the standby configuration for many hours a day, total consumption is other than negligible.
It is an object of the present invention to provide a connecting device designed to eliminate the aforementioned drawbacks.
According to the present invention, a device for connecting electric household appliances to an electric power main is provided, as claimed in the attached Claims.
Some non-limiting embodiments of the invention will be described by way of example with reference to the accompanying drawings, in which:
As shown in
Multiple socket 1 comprises a casing 4; an input line 5 connectable to terminal 2 of mains 3 by means of a plug 6; a number of output terminals 7 incorporated in casing 4; and a safety circuit 8 housed in casing 4 and connected between input line 5 and output terminals 7.
Plug 6 and output terminals 7 are standard types to current standards. Various types of household appliances are connected to respective output terminals 7 of multiple socket 1. More specifically,
Safety circuit 8 comprises a noise filter 9; a selective coupling stage 10 between input line 5 and output terminals 7; a power detection stage 11; a driving stage 12; and an electromagnetic signal sensor 13.
Selective coupling stage 10 is controlled by power detection stage 11 via driving stage 12, as explained below, and comprises a three-contact relay 15. A first and second contact 15a, 15b of relay 15 are connected respectively along a first and second conductor 18, 19 (phase and neutral) of input line 5, downstream from noise filter 9, and are normally open (i.e. are open when relay 15 is not energized). In other words, first and second contact 15a, 15b respectively define a first and second switch, which are connected along first and second conductor 18, 19 and isolate terminals 7 from input line 5 when relay 15 is not energized. A normally-closed third contact 15c is connected between electromagnetic signal sensor 13 and a battery 25, which supplies it as explained below.
A first and second triac thyristor 20, 21 are connected in parallel to first and second contact 15a, 15b respectively of relay 15, and are controlled by electromagnetic signal sensor 13.
More specifically, electromagnetic signal sensor 13 is an infrared receiver outside casing 4 of multiple socket 1 and connected to respective control terminals 20a, 21a of first and second triac thyristors 20, 21 by a connecting cable 23 and a connector 24. More specifically, electromagnetic signal sensor 13 is of a type suitable for picking up signals emitted by infrared remote controls, and is also powered by independent battery 25. In the presence of a signal emitted by an infrared remote control, electromagnetic signal sensor 13 supplies a control current Ic to control terminals 20a, 21a of triac thyristors 20, 21, which conduct. In an alternative embodiment, electromagnetic signal sensor 13 is a radiofrequency receiver; and a further embodiment comprises a number of infrared and/or radiofrequency electromagnetic signal sensors. Battery 25 may be connected temporarily to control terminals 20a, 21a of triac thyristors 20, 21 by a normally-open manual reset switch 26.
Detection stage 11 is cascade connected to selective coupling stage 10, and measures the electric power drawn over input line 5 by the loads connected to output terminals 7. For which purpose, outputs 11a of detection stage 11 are connected to the driving stage 12, and supply a measurement signal SW correlated to the power drawn. In other words, selective coupling stage 10 is connected between input line 5 and detection stage 11, so that detection stage 11 and driving stage 12 are also disconnected from input line 5 when input line 5 is disconnected from output terminals 7.
Driving stage 12 comprises an amplifier 27, a rectifier 28, a comparator 30, a calibration circuit 31, and a bistable—in this case, a set/reset—element 32.
Amplifier 27, rectifier 28, and comparator 30 are cascade connected to one another. More specifically, amplifier 27 has inputs connected to the outputs of detection stage 11 to receive measurement signal SW, and outputs connected to rectifier 28, which is preferably a double half-wave type. Comparator 30 is a hysteresis, trigger threshold type, e.g. a Schmitt trigger, and has a rise trigger threshold STHP and a fall trigger threshold STHN. Comparator 30 receives the amplified, rectified measurement signal SW′ from rectifier 28, and switches when measurement signal SW′ runs below the fall trigger threshold STHN or exceeds the rise trigger threshold STHP. Outputs of comparator 30, at which opposite voltage values are present, are connected respectively to a set input 32a and a reset input 32b of bistable element 32, which has an output connected to a control terminal 15d of relay 15. More specifically, when the amplified, rectified measurement signal SW′ exceeds rise threshold STHP, the set input 32a of bistable element 32 is forced to a high value, and the output of bistable element 32 is high and energizes relay 15, so that first and second contact 15a, 15b close or remain closed; the third contact 15c, on the other hand, is open, so that electromagnetic signal sensor 13 is not powered to save battery 25. Conversely, when the amplified, rectified measurement signal SW′ is below fall threshold STHN, the reset input 32b of bistable element 32 is forced to a high value, so that the output of bistable element 32 is low. In which case, relay 15 is not energized, so that first and second contact 15a, 15b are open, while third contact 15c closes to connect battery 25 to electromagnetic signal sensor 13.
Calibration circuit 31 is connected to a calibration terminal 30a of comparator 30 to regulate rise and fall trigger thresholds STHP, STHN thereof. More specifically, calibration is carried out so that the amplified, rectified measurement signal SW′ is below fall trigger threshold STHN when all the user devices connected to output terminals 7 of multiple socket 1 (in the example shown, television 9a) are in the energy-saving or standby configuration.
Multiple socket 1 operates as follows. When at least one of the user devices connected to output terminals 7 is operating, the power draw measured by detection stage 11 is sufficient for the amplified, rectified measurement signal SW′ to exceed rise threshold STHP of comparator 30, so that the output of bistable element 32 is high and energizes relay 15. The first and second contact 15a, 15b remain closed, and keep output terminals 7 connected to input line 5, and therefore to mains 3, so that television 9a and any other user devices connected to multiple socket 1 can operate normally.
When television 9a and all the user devices connected to multiple socket 1 are set to the standby configuration, detection stage 11 detects such a fall in power draw from mains 3 that the amplified, rectified measurement signal SW′ runs below fall trigger threshold STHN; comparator 30 and bistable element 32 switch, thus de-energizing relay 15; the first and second contact 15a, 15b therefore open; the connection between output terminals 7 and input line 5 is thus cut off; and the user devices connected to multiple socket 1 are isolated from mains 3, while the electromagnetic signal sensor is powered.
When activation of one of the user devices is requested by use of the respective remote control (in particular, television 9a using remote control 9b), electromagnetic signal sensor 13 picks up the signal (infrared) emitted by the remote control, and, in response, supplies control current IC to control terminals 20a, 21a of triac thyristors 20, 21; triac thyristors 20, 21 are temporarily turned on and establish conducting paths parallel to relay 15; output terminals 7 are therefore reconnected to input line 5 to power the user devices; the power draw is detected by detection stage 11, which closes relay 15 via driving stage 12, as explained above; and, at this point, output terminals 7 and input line 5 remain permanently connected even if triac thyristors 20, 21 are disabled again, when third contact 15c opens to cut off power to electromagnetic signal sensor 13. Alternatively, input line 5 and output terminals 7 may be reconnected using manual reset switch 26 to connect battery 25 to control terminals 20a, 21a of triac thyristors 20, 21.
In other words, the power draw of at least one active user device keeps input line 5 and output terminals 7 connected; when the power draw level indicates all the user devices connected to multiple socket 1 are in the standby configuration, output terminals 7 are automatically disconnected from input line 5 and remain isolated. The user devices connected to multiple socket 1 are therefore advantageously protected against overloads on mains 3, and power draw is zeroed. Moreover, detection stage 11 and driving stage 12 are also disconnected from mains 3 and surge-protected when none of the user devices connected to multiple socket 1 is actively in use. Simply operating the remote control of any one of the user devices connected to multiple socket 1, however,—in particular, remote control 9b of television 9a—is sufficient to reconnect input line 5 and output terminals 7 and activate the relative user device. Multiple socket 1 therefore maintains the advantages of the standby configuration, and in particular the possibility of rapidly reactivating the user devices connected to multiple socket 1.
In a further embodiment of the invention shown in
Clearly, changes may be made to the connecting device as described herein without, however, departing from the scope of the present invention as defined in the accompanying Claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2005A000521 | Mar 2005 | IT | national |
