EP2638778A1 - Household appliance - Google Patents

Abstract

The invention relates to a domestic appliance (1), comprising a door (3), a door frame (6) for placing the door (3) against same in the closed state, and at least one switch (8; 9) for detecting a closed state of the door (3), characterized in that the door frame (6) and the door (3) form at least one non-mechanically triggered switch (8; 9).

Description

 household appliance

The invention relates to a household appliance, comprising a door, a door frame for supporting the door in the closed state and at least one switch for detecting a closed state of the door.

In an operation of microwave ovens, safety-related switching functions such as e.g. a shutdown when opening a door, a failure of a microwave trap, etc. are ensured by not mechanically triggering switches. Disadvantageously, however, the electromechanical switches require a not inconsiderable space and generate costs.

For example, from DE 1 195 884 B, from US Pat. No. 4,059,742 or from US Pat. No. 4,166,207, silicone seals which are rendered conductive by means of graphite or carbon black for microwave devices are known. As a result, an improved protection against microwave leakage radiation is achieved. However, silicon gaskets filled or filled with graphite are weakened in their mechanical properties compared to unfilled silicones.

It is the object of the present invention to provide a household appliance of the type mentioned above, which at least partially eliminates one or more disadvantages of the prior art.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The object is achieved by a household appliance, comprising a door and a door frame for supporting the door in a closed state. The door frame and the door are adapted to generate at least one non-mechanically triggering switching function.

Such a household appliance has the advantage that on dedicated switches for detecting the closed state (open or closed state), in particular on mechanically triggering switch can be dispensed with. As a result, space and costs can be saved. In addition, a flat construction is possible.

The door frame and the door may in particular form at least one non-mechanically triggering switch. Such a switch can be configured here generally as a switching element, and in particular switch in the strict sense as well as buttons, including sensor buttons include.

It is an embodiment that the door frame and the door generate at least one electrically triggering switching function, in particular form at least one electrically triggering switch. Alternatively, the door frame and the door can generate at least one capacitively triggering switching function, in particular form at least one capacitively triggering switch (especially sensor switch). The switch can close or open a circuit of the household appliance and thus trigger a predetermined behavior of the household appliance.

It is a development that the door frame and the door each have at least one electrically conductive contact area, which lie on one another in the closed state of the door or contact each other. As a result, for example, a circuit can be closed electrically, as a result of which the closed state (open and / or closed state) of the door can be detected. Alternatively, the contact areas may represent parts of a capacitive proximity sensor, which is a switch or circuit or integrated in such. It is an advantageous embodiment, in particular for electrical switches, that the door frame or the door has at least one electrically conductive contact area and the door or the door frame has at least two contact fields resting on the contact area in the closed state of the door. The contact fields are spaced apart. For example, when the door is in the open state, the contact area and the contact pads are spaced apart, and the contact pads may be electrically isolated from each other, for example. When the door is closed, the contact area bridges the contact fields, which can be detected accordingly. Alternatively, the contact area and the contact pads may allow for capacitive switching. It is yet an embodiment that the electrically conductive contact region has at least one seal and the at least one seal is electrically conductive. This allows a particularly secure operation of the switch. In addition, a tolerance compensation can be provided by the seal.

It is still another embodiment that the gasket has carbon nanotubes. The carbon nanotubes allow a very high electrical conductivity of the seal. The carbon nanotubes may comprise single walled tubes (SWCNT) and / or multiwalled tubes (MWCNT). The carbon nanotubes may comprise open and / or closed tubes. The carbon nanotubes may be empty and / or filled. The seal may additionally or alternatively comprise graphene.

It is also an embodiment that the seal silicone, rubber or thermoplastic see elastomers (TPE) see as a base material in which the carbon nanotubes are distributed. This seal has the advantage of improving its mechanical strength over normal seal materials not filled with carbon nanotubes. It is also an embodiment that the contact pads comprise non-precious metal-containing, electrically conductive particles (e.g., copper and / or other semi-precious metal, graphite, graphene, carbon nanotubes, etc.). By eliminating precious metal (e.g., Au, Pd, Au, etc.), inexpensive producible and easily applied contact pads can be provided.

It is also an embodiment that the non-noble metal-containing, electrically conductive particles are distributed in a screen printing paste. This allows the contact fields to be easily printed. In particular, a print layout for the contact fields, e.g. possible with glass panes.

Alternatively, for example, application by means of spray painting, roller coating, roller coating, screen printing coating, ink pressure coating or a combination of these methods is also possible. The non-noble metal-containing, electrically conductive particles may be distributed, for example, during their application in a fluid. It is still an embodiment that the door frame and the door form a plurality of non-mechanically triggering, in particular redundant, switch. As a result, the closed state of the door can be detected particularly reliably. For example, more than two contact fields may also be present, which form two or more independently triggering switches. The plurality of switches may in particular be electrically connected in series.

It is still an embodiment that the household appliance has a microwave function (microwave oven). The microwave device may be a single device or a combination device, e.g. with an oven function. In particular, if the microwave oven or its door or door frame has an electrically conductive seal, there is an additional improvement in the microwave shielding. However, other household appliances may also be designed, e.g. Dishwashers, washing machines, ovens, etc.

The object is also achieved by a method for detecting a closed state of a door of a household appliance, wherein the closed state is detectable by an approach (or a distance) or by contacting at least one respective electrical contact region of the door and a door frame. This method gives the same advantages as the household appliance described above.

It is a development that the closed state can be detected by an approach (or a distance) or by contacting an electrically conductive seal of the door or the door frame at least one contact region of the door frame or the door. The gasket may in particular have been rendered electrically conductive by carbon nanotubes.

The method can be further designed analogously to the household appliance described above.

In the following figure, the invention will be described schematically with reference to an embodiment schematically. The Fig. Shows a household appliance in the form of a microwave oven 1. The microwave oven 1 has a cooking chamber 2, which is closable by means of a pivotable door 3. The door 3 has a microwave-tight window 4, which is surrounded by and supported by a peripheral frame, the window frame 5. The window frame 5 is in the closed state of the door 3 on a matching door frame 6. The door frame 6 can be formed for example by a body or a housing wall of the microwave oven 1.

At its resting on the door frame 6 back 7, the window frame 5 has a circumferentially closed microwave seal (o.Abb.) Or a part thereof, wherein the microwave seal an undesired lateral leakage of microwave radiation between the back 7 of the window frame 5 and the door frame 6, for example can be strongly suppressed or even prevented by negative interference of microwave radiation. Alternatively or additionally, such a type of microwave seal can also be present on the door frame 6.

In order to prevent the door 3 from violently landing on the door frame 6 when closing, and to provide a thermal barrier, the door frame 6 additionally has an encircling rebounding seal 8 at the front (i.e., forward towards the door 3). This seal 8 has silicone as the base material, which is set electrically conductive by carbon nanotubes. The electrical conductivity further suppresses possible leakage radiation through a gap between the door frame 6 and the door 3. Also, in particular assembly tolerances and / or material deformations can be compensated during operation. The carbon nanotubes also make the silicone seal particularly resistant to mechanical stress.

On its back 7, the door 3 on one side (here the top) equidistantly distributed, localized contact fields 9. The contact fields 9 may contain, for example, silver or a silver / palladium mixture and may have been applied by means of a screen printing process, for example. The contact fields 9 approach when closing the electrically conductive seal 8. The seal 8 and the contact pads 9 form parts of a switch which is arranged in a circuit. Depending on whether the switch is a capacitive proximity switch or an electrical switch, the switch is at a sufficient approximation or only at a mechanical Contact closed. For example, to close the electrical switch, the electrically conductive seal 8 electrically bridge or short pairs of contact pads 9. By opening and / or closing the switch, an action can be triggered by means of the circuit. For example, by closing the switch, an operation of the microwave oven 1 can be made possible. Conversely, the circuit can respond to opening of the switch by lifting the door from the door frame 7. For example, in an activated microwave oven 1 by opening the door 3 and thus by opening the switch 8, 9 a microwave operation can be interrupted and optionally an audible or visual warning signal are triggered. The switch 8, 9 can thus be used in particular as an emergency stop switch.

By providing the three contact fields, increased detection reliability can be achieved, for example by the three contact fields 9 forming two switches of a switching circuit connected electrically in series.

Of course, the present invention is not limited to the embodiment shown.

Thus, the electrically conductive seal on the door, especially at the window frame, if any, be present.

The door can generally be designed differently, for example, frameless. In particular, in the case of a frameless door, the electrically conductive seal and / or the contact fields can be applied directly to the cover, eg a glass pane. LIST OF REFERENCE NUMBERS

1 microwave oven

2 cooking space

 3 door

 4 windows

 5 window frames

6 door frame

7 back side

8 seal

9 contact field

Claims

claims Household appliance (1), comprising a door (3) and a door frame (6) for supporting the door (3) in a closed state, characterized in that the door frame (6) and the door (3) are adapted to generate at least one non-mechanically triggering switching function (8; 9). Domestic appliance (1) according to claim 1, characterized in that the door frame (6) or the door (3) have at least one electrically conductive contact area and the door (3) or the door frame (6) at least two in the closed state of the door (3 ) has contact areas (9) resting on the contact area. Domestic appliance (1) according to claim 2, characterized in that the electrically conductive contact region has at least one seal (8) and the at least one seal (8) is electrically conductive. Domestic appliance (1) according to claim 3, characterized in that the seal (8) comprises carbon nanotubes and / or graphene. Domestic appliance (1) according to claim 4, characterized in that the seal (8) silicone, rubber or thermoplastic elastomers (TPE) as a base material, in which the carbon nanotubes are distributed. Domestic appliance (1) according to one of claims 2 to 5, characterized in that the contact fields (9) non-precious metal-containing, electrically conductive particles, in particular carbon nanotubes have. Domestic appliance (1) according to one of claims 4 to 6, characterized in that the carbon nanotubes are distributed in a screen printing paste. 8. Household appliance (1) according to one of the preceding claims, characterized in that the door frame (6) and the door (3) generate at least one electrically triggering switching function (8; 9). 9. Household appliance (1) according to one of the preceding claims, characterized in that the door frame (6) and the door (3) generate at least one capacitively triggering switching function (8; 9). 10. Household appliance (1) according to one of the preceding claims, characterized in that the door frame (6) and the door (3) form a plurality of non-mechanically triggering switching functions (8; 9). 11. Household appliance (1) according to one of the preceding claims, characterized in that the household appliance (1) has a microwave function.