EP2048274A1

EP2048274A1 - Home appliance including detection system for presence of a living being within appliance and method for operating the same

Info

Publication number: EP2048274A1
Application number: EP07019689A
Authority: EP
Inventors: Alberto Pezzutto
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2007-10-09
Filing date: 2007-10-09
Publication date: 2009-04-15

Abstract

The invention relates to a home appliance and a method for operating the same, in particular a dishwasher (2), dryer or washing machine comprising: an outer casing; an internal compartment (24); at least one detector (12, 14, 16, 17), wherein the at least one detector is adapted to generate a detection signal and/or a signal indicative for a presence of a living being in the internal compartment (24); and a control unit'(4) adapted to prevent a start or continuation of a program to be executed in the home appliance when receiving a detection and/or indicative, signal from the at least one detector (12, 14, 16, 17)an outer casing; an internal compartment (24); at least one detector (12, 14, 16, 17), wherein the at least one detector is adapted to detect a presence of a living being in the internal compartment (24), in particular a presence of a child and/or animal, and a control unit (4) adapted to prevent a start or continuation of a program to be executed in the home appliance when a receiving a signal from the at least one detector (12, 14, 16, 17).

Description

The present invention relates to a home appliance, in particular to a dishwasher, dryer or washing machine, and a method for operating the appliance.
As described in DE 10 2004 002 008 Al a safety lock is provided to prevent accidental access of children to home appliances, in particular to a tub of a dishwasher.
It is an object of the invention to further improve the safety of home appliances.
The invention is defined in claims 1 and 10, respectively.
Particular embodiments are set out in the dependent claims.
Obviously a running program of the home appliance like e.g. a dishwasher would lead to injury, poisoning or even death of a child or animal located inside the compartment due to the humid and close environment and the presence of detergent and its vapours. Even without a running program a child being confined in the compartment due to a closed door of the compartment would undergo a risk of suffocation. By providing a home appliance according to claim 1 this risk is minimized and therefore the safety of the appliance is increased.
According to claim 1 the home appliance comprises an outer casing having an internal compartment. The internal compartment can be a drum of a washing machine or dryer or a tub of a dishwasher. At least one detector is provided, wherein the detector is adapted to generate a detection signal and/or a signal indicative for a presence of a living being in the internal compartment. The living being to be detected can be a child or an animal like a pet located inside the compartment e.g. due to curiosity. A control unit,is provided which is adapted prevent a start or continuation of a program of a home appliance when a signal from a detector is received.
The communication between the at least one detector and the control unit is made for example via a fixed line or wireless.
Preferably the at least one detector is either active or passive. A passive detector generates a signal provided to the control unit which is subsequently evaluated or analyzed by the control unit. The control unit evaluates the received signal e.g. by comparing the signal with a threshold or comparison value and prevents a start or continuation of a selected program when the detected signal is equal to or exceeds the threshold value, i.e. when the signal indicates an anomalous state or occurrence in the compartment. The threshold or comparison value is set to a level, wherein exceeding this value represents a high probability that a living being is located inside the compartment. For example a predetermined temperature value stored in the control unit is compared to the detected temperature value(s) of an infrared sensor, whereby the predetermined temperature is set to a level which a living being would radiate when located inside the compartment.
An active sensor provides a detection signal to the control unit when detecting an anomalous state or occurrence in the compartment. For example a motion sensor uses ultrasonic or electromagnetic waves which are transmitted by a transmitter to the compartment and the reflections of the waves are received by a receiver of the motion sensor. By comparing the background signal of the compartment with the actual received signal a change in the observed area by the sensor is detected and subsequently a detection signal is provided to the control unit. When the control unit receives a detection signal from an active sensor a start or a continuation of a program is immediately stopped by the control unit. Another example of a motion sensor is a PIR-sensor using pyroelectrical effect of piezoelectric crystals. The PIR-sensor reacts to movements of infrared radiating objects in the observed area thereby combining a detection of movement and temperature. This is particularly advantageous as a detection of e.g. a (cool) dish which drops or falls down in a basket of a dishwasher can be distinguished from a living being radiating body heat and a false alarm is prevented.
Generally a detected signal corresponds to an anomalous state or occurrence in the compartment which in turn correspond to a probability of a presence inside the compartment.
Preferably two or more detectors are provided and by arranging detectors at different positions inside the compartment a larger area in the compartment can be observed and therefore the probability for detecting a presence inside the compartment increases. In a preferred embodiment the at least one detector is located at a wall of the internal compartment, in particular on the outer or inner surface of the compartment. By locating a detector on the outer surface of the compartment the detector is protected e.g. from the water and detergents of the appliance during a program cycle which increases the service life of the detector.
Preferably the detector is located at the bottom of the compartment or a lower part of the compartment to increase the probability of detecting a living being. In case a child or animal is inside the compartment it is likely to be situated in a lower part of the appliance, e.g. lower part of the tub of a dishwasher, in view of the usual location of appliances on the floor which facilitates the access of a child or animal to the lower part of the compartment.
In a preferred embodiment the at least one detector is located on a basket, rail and/or roller of a dishwasher. For example a pressure sensor is located at a position of the rail where a roller of the basket is located when the basket is or is approximately in the correct position inside the compartment i.e. tub of the dishwasher. By providing a signal to the control unit, when the roller exerts pressure to the pressure sensor on the rail, the correct position of the basket inside the tub can for example be controlled. Alternatively or additionally, a living being in the compartment which dislocated the basket (e.g. by lifting or shifting) and/or exerts excessive pressure by the abnormal and additional weight of the living being can thereby be detected. Another way of detecting a dislocated basket or the presence of the basket inside the tub is provided by RFID-tags provided on a basket or on rollers of the basket and a reader checking the presence of the basket e.g. located at a wall of the tub.
According to a preferred embodiment the at least one detector has, additionally to the above described function to detect a presence of a living being, the further function to detect an operating state of the appliance. Such a dual-function of a detector is provided for example by a pressure sensor. Additionally to the detection of a presence of pressure exerted e.g. by a living being inside the tub or by another item located on top of the sensor, the sensor detects the water level during a program cycle, thereby controlling whether a required water level during the program cycle is achieved. In an alternative or additional embodiment, a motion sensor can detect a rotation of a sprayer arm of the dishwasher thereby detecting whether the dishwasher is operating correctly during a program cycle where the sprayer arms should rotate. Additionally or alternatively a temperature sensor like an infrared sensor can additionally detect the temperature of the hot dishes after a program cycle and by informing the user of the detected temperature the risk of the user to burn himself by trying to unload the hot dishes is minimized.
By the combined using of several different detectors, e.g. a motion sensor and an infrared sensor, the probability for detecting at least one of the different signs of live (e.g. movement, noise, body heat) of a living being inside the compartment is increased. For example from a quiet e.g. sleeping or unconscious living being body heat can be detected by the infrared sensor.
Preferably a detector is located at a position that provides the best overview over the internal compartment. For example a motion, noise or acceleration sensor is provided in an upper region of a compartment. Whereas a weight sensor or pressure sensor is located in a lower part of the compartment where a living being is likely to be located when being inside the compartment.
Preferably the appliance further comprises an indicator unit adapted to indicate a detected presence. In case a child or animal is located or confined inside the compartment a user is informed by the indicator unit of the emergency situation.
The indication itself can be optical, acoustical and/or mechanical and a change or modification can be made between these modes. Other types of changes are indicating different states of urgency using different melodies, different noise levels, frequency of noise, the intensification of a mechanical vibration, a shortening of the periods of changes between different indications and so on.
Preferably the intensity of the signal increases in dependency of the elapsed time since the control unit received a detection and/or a signal indicative for a presence of a living, being. By increasing a frequency of the signal in dependency of the elapsed time the increasing urgency of taking action is indicated to a user or any person within earshot. This is particularly important when a living being is confined due to a closed door of the compartment as the risk of suffocation inside the compartment increases with time.
In a preferred embodiment the indicator unit is a remote indicator unit which is adapted to communicate with the appliance or receive signals from the appliance. The communication with the control unit is made for example via a fixed line, a flexible line or wireless, including a local area network, Bluetooth technique, a communication to the DECT telephone system, communication with a handy and so on.
A method for operating a home appliance according to any of the above described embodiments comprises an activating of the at least one detector and further a preventing of a start or a continuation of a selected program of the appliance when a control unit receives a detection signal from the at least one detector. Additionally or alternatively the start or continuation is prevented when the control unit receives a signal indicative for a presence as described above.
When a detection signal or an indicative signal, representing the high probability of a presence of a living being or the occurrence of an anomalous state of the appliance, is received by the control unit during a program cycle that, the control unit stops the running program.
After a detection of a presence of a living being (or an anomalous state) an indication signal is given to a user or any other person in reach as described above. Preferably the indication comprises an emergency signal as known from fire alarms.
By activating the detector e.g. between one minute and ten minutes and preferably between one minute and five minutes after the door to the compartment is closed and/or before a selected program is executed, it is guaranteed that enough time is provided for a detection of a living being inside the compartment.
By already activating the detector when a door of the compartment is closed even before a start of a selected program the risk of suffocation of a confined living being is prevented. Also the detection before any of the moving parts of an appliance are activated is particularly advantageous in view of the danger of injury of a living being by the moving parts, like the sprayer arms of a dishwasher.
Preferably at least one detector is activated during a program cycle, in particular at the beginning of a selected program cycle. In case a living being has not been detected before the program starts, this embodiment provides a further chance to detect a child or animal inside the compartment. When the control unit receives a signal from a detector during a program cycle, the running program cycle is immediately stopped and an indication signal is provided.
Reference is made in detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings which show:

Fig. 1: a dishwasher according to a preferred embodiment,
Fig. 2: a block diagram of elements of the dishwasher of Fig. 1,
Fig. 3: a flow chart depicting an exemplary method for operating a home appliance, in particular the dishwasher of Fig. 1.

Fig. 1 shows a dishwasher 2 having an outer casing (not, shown) and a tub 24. The dishwasher comprises a lower basket 22 and an upper basket 20 which is guided on the respective lower rails and upper rails 32, 34 via upper and lower rollers 36, 38. A central processing unit 4 (see Fig. 2) of the dishwasher controls the program sequences of the dishwasher 2 according to the selections made by a user via an input panel 8 (see Fig. 2). During operation of the dishwasher cleaning liquid 30 or water is supplied to an upper and a lower spray arm 26, 28 of the dishwasher by the pump unit 6.
At an upper part of the tub 24 an infrared sensor 16 and a noise sensor 14 are located at the inner wall of tub 24, both providing a wide volume coverage for infrared emission and sound emission, respectively.
The infrared sensor 16 is adapted to detect a source of infrared emission inside the tub 24, in particular before (hot) cleaning liquid is supplied into the tub 24. The infrared detector 16 detects the temperature distribution inside the tub 24 and provides the detected distribution i.e. temperatures to the control unit 4 which subsequently compares the detected temperatures with a predetermined threshold value. The threshold value is set to a temperature level corresponding to a level of temperature that a living being inside the tub 24 would emit due to body heat. By the infrared sensor 16 the probability of detecting a child or an animal which is not moving (e.g. sleeping) inside the tub 24 is increased. Additionally the infrared sensor provides a detection of the temperature of the cleaned dishes during or after a program cycle. For example, an indication that the temperature of the cleaned dishes is too high to be removed from the dishwasher can be indicated via an indicator section 10 (see Fig. 2).
The noise sensor 14 is adapted to detect any noise occurring inside the tub 24 and supplies the detected signals to the control unit 4. Before a program of the dishwasher is started the control unit 4 compares the detected noise level with a predetermined noise level and a high probability of a living being inside the tub is assumed when a detected noise signal is equal to or exceeds the predetermined noise level. During a program cycle, the noise sensor 14 monitors the undisturbed rotation (i.e. nearly noiseless) of the sprayer arms 26, 28. Thereby recurrent noise can be detected when a sprayer arm 26, 28 repeatedly collides with e.g. dishes extending into the area of the rotating sprayer arms 26, 28.
A motion sensor 12 is located on a side of the tub 24. The motion sensor 12 is adapted to detect movements within the tub 24 and comprises an ultrasonic transmitter and receiver to detect changes in the observed area. The sensor 12 transmits ultrasonic waves and receives the reflection of these waves. By comparing a reference value with the actual value of the reflection, a change in the observed area is detected, wherein the reference value (background value) is generated when the motion sensor is activated. A detected change can relate to any moving inside the tub 24 like a rotating sprayer arm or a moving of a living being. When the motion sensor 12 detects a movement, before any of the moving parts of the appliance, i.e. sprayer arms 26, 28, are activated, a signal indicative for the detection of a presence is provided to the control unit 4. During operation of the dishwasher the motion sensor 12 detects rotation of spray arm 26 (at,this position) to verify proper, operation of the dishwasher when e.g. liquid is circulated and the spray arms should notate.
A pressure sensor 17 is located at the outer wall of the bottom part of the tub 24 for detecting the level of cleaning liquid 30 in the lower part of the tub 24. The pressure sensor 17 is provided on the outside of the tub 24 to protect the sensor 17 from water and detergents during a program cycle. The pressure sensor 17 is a piezoelectric sensor which provides a signal to the control unit 4 which indicates the pressure onto the lower part of the tub 24 produced by the cleaning liquid 30 during a program cycle, thereby a sufficient supply of cleaning water is controlled. When the pressure detector 17 detects a pressure before water or cleaning liquid is supplied to the tub 24, produced e.g. by a child situated at the bottom part of the tub 24 exerting pressure on the sensor 17, the pressure sensor 17 transmits a detection signal to the control unit 4 indicating the anomalous occurrence of pressure, which indicates a probability of a presence in the tub 24.
The provision of the several different sensors 12, 14, 16, 17 increases the probability for detecting one of the different signs of a living being inside the tub 24, that may emit different types of signals indicating its presence, like movements, noise or body heat.
Additionally a door sensor 19 (see Fig. 2) provides a signal to the control unit 4 when a front door to the tub 24 of the dishwasher 2 is closed. When the control unit 4 receives the closing or closed signal from the door sensor 19, the above mentioned sensors 12, 14, 16, 17 are activated by the control unit 4 for at least one minute. Thereby the risk of suffocation for a living being confined inside the tub 24 due to the closed door is minimized.
Fig. 2 shows the principle structure of elements of the dishwasher 2 in a block diagram. The dishwasher is activated by I/O unit 18. The sensors 12, 14, 16, 17 are either passive or active (intelligent) sensors with respect to the detection of a presence of a living being inside the tub 24.
The passive sensors, infrared sensor 16 and noise sensor 14, provide a signal indicative for a presence to the control unit which in turn evaluates the signal by comparing the detection signal with a threshold or comparison value to determine a probability of a presence inside the tub 24. In case the signal is equal to or exceeds the comparison or threshold value, the control unit 4 activates the indicator section 10 to provide an indication signal to a user or any other person in reach.
The active sensors, motion sensor 12 and pressure sensor 17, provide a detection signal to the control unit 4 indicating the presence of a living being in the tub 24. In response to a detection signal of an active detector the control unit 4 activates the indicator section 10 to indicate a presence inside the tub 24 wherein the indicator section 10 comprises a display to provide an optical signal and speakers to provide an acoustic signal.
Further, the control unit 4 receives a signal transmitted from door sensor 19 when the door of the appliance is closed. When the control unit 4 receives a signal from sensor 19 the sensors 12, 14, 16, 17 are activated by the control unit 4, preferably at least one minute. Also, when the control unit 4 receives a signal from the input unit 8 because a program cycle is selected by the user, the detector elements are activated by the control unit 4, preferably for at least one minute.
Fig. 3 shows an exemplary embodiment for a method for operating a home appliance, in particular the dishwasher 2 according to the above described embodiment. After the start (switch-on) of the appliance the control unit 4 checks whether a program is set by determining whether a program has been selected by the input panel 8. In case a program is set, the control unit 4 checks whether a door of the appliance is closed by determining whether a signal of the door sensor 19 is received. When a program is set and the door is closed the sensors 12, 14, 16, 17 are activated by the control unit 4. The sensors are kept active, preferably more than or equal to one minute. If in this time span no anomalous occurrence or state i.e. presence has been detected according to the above described methods, the selected program is executed by the control unit 4. In case a sensor detects an occurrence or state representing the probability of a presence of a living being, the control unit 4 activates the indicator section 10 to provide an indication signal. In the latter case the selected program will not be executed until a user has checked the appliance.

Reference Numerals List

2: dishwasher
4: control unit
6: pump unit
8: input panel
10: indicator section
12: motion sensor
14: noise sensor
16: infrared sensor
17: pressure sensor
18: I/O unit
19: door sensor
20: upper basket
22: lower basket
24: tub
26: upper spray arm
28: lower spray arm
30: cleaning liquid
32: upper rail
34: lower rail
36: upper rollers
38: lower rollers

Claims

Home appliance, in particular dishwasher (2), dryer or washing machine, comprising:
an outer casing;

an internal compartment (24);

at least one detector (12, 14, 16, 17), wherein the at least one detector is adapted to generate a detection signal and/or a signal indicative for a presence of a living being in the internal compartment (24); and

a control unit (4) adapted to prevent a start or continuation of a program to be executed in the home appliance when receiving a detection and/or indicative signal from the at least one detector (12, 14, 16, 17).
Appliance according to claim 1, wherein the at least one detector (12, 14, 16, 17) is located at a wall of the internal compartment (24), in particular on the outer or inner surface or wall of the internal compartment (24).
Appliance according to claim 1 or 2, wherein the at least one detector (12, 14, 16, 17) is located on a lower basket (22), upper basket (20), on at least one roller of a basket, a lower basket rail and/or an upper basket rail of the appliance.
Appliance according to any of the previous claims, wherein the at least one detector is additionally adapted to detect an operating state of the appliance.
Appliance according to claim 4, wherein the operating state is a water level, temperature and/or rotation of a sprayer arm.
Appliance according to any of the previous claims, wherein the at least one detector (12, 14, 16, 17) is selected from a group of: motion sensor, acceleration sensor, pressure sensor, weight sensor, noise sensor, temperature sensor, infrared sensor, RF-sensor.
Appliance according to any of the previous claims, further comprising an indicator unit (10) adapted to indicate a detected presence.
Appliance according to any of the previous claims, wherein the indicator unit (10) is adapted to provide an acoustic signal and/or an optical signal.
Appliance according to any of the previous claims, wherein the indicator unit (10) is adapted to vary the type, time behavior and/or intensity of the acoustic and/or optical signal, in particular in dependency of the time elapsed since the control unit received a detection signal and/or indicative signal.
Method for operating a home appliance, in particular a home appliance according to any of claims 1 to 9, comprising the steps of:
activating at least one detector (12, 14, 16, 17); and

preventing a start or continuation of a program to be executed by the home appliance when a control unit (4) receives a detection signal and/or indicative signal from the at least one detector (12, 14, 16, 17).
Method according to claim 10, wherein the control unit (4) is adapted to stop or abort a selected program when receiving a detection and/or indicative signal.
Method according to claims 10 or 11, wherein the control unit (4) is adapted to activate an indicator unit (10) when receiving a detection and/or indicative signal.
Method according to claims 10, 11 or 12, wherein the control unit (4) is adapted to monitor and/or analyze the signal(s) of the at least one detector (12, 14, 16, 17) for at least 10 sec, preferably at least 20, 40 or 60 sec, after a door of the appliance is closed and/or before any moving parts of the appliance are activated.