EP3493016B1 - Domestic appliance - Google Patents

Description

The present invention relates to a household appliance, in particular a household cooking appliance.

Operating elements for household appliances, such as rotary switches or the like, include an actuating shaft that is rotatably mounted in a housing of the operating element. A rotary knob can be provided on this actuating shaft, which is coupled to the actuating shaft with the aid of a leaf spring, for example.

the EP 2 620 831 A2 shows a control element for a valve of a household appliance. The operating element comprises a gripping surface for gripping the operating element by a user and a coupling device for releasably coupling the operating element to a valve shaft of the valve, the coupling device having a snap element which is adapted to a corresponding element of the valve shaft in order to form a snap lock with it .

the DE 10 2012 224 126 A1 describes a switch assembly for household appliances with a rotary switch, a toggle and a fixing element for fixing the toggle on a switching axis of the rotary switch. The fixing element is arranged between the switching axis and the toggle. The fixing element has an opening, as a result of which it can be pushed onto the shifting axle.

the EP 1 385 076 A1 shows a rotary switch device with a carrier element and a switch, the switch shaft of which can be actuated via an actuating unit. A shaft is injection-molded onto the support element and, in the assembled state, is coupled to the switch shaft of the switch via a coupling point.

the EP 2 980 672 A2 shows a control element for a household appliance with a cylindrical control element button, which is arranged to be rotatable about a longitudinal axis of the control element, and with a hollow control element button receptacle, into which the control element button extends at least in regions, and which around the longitudinal axis is closed all the way round, wherein the operating element head receptacle is formed from at least two separate parts.

the DE 10 2008 042 826 A1 describes a domestic appliance operating device with at least one bearing, which has at least one bearing body, and with at least one handle and at least one coupling unit, which couples the handle to the bearing body, with the coupling unit being intended to fasten the handle in a detachable manner without destroying it.

the JP 2011 059990 A shows a control element for a device. The operating element includes an operating shaft and a rotary knob. A torque transmission device for transmitting a torque from the rotary knob to the actuating shaft is provided between the actuating shaft and the rotary knob. The rotary knob has an engaging portion. The torque transmission device has a counter-engagement section, in which the engagement section engages.

the FR 2 780 111 A1 also describes a control element for a device. The operating element comprises a turning knob, an actuating shaft and a torque transmission device which is arranged between the turning knob and the actuating shaft. The torque transmission device is connected to the actuating shaft and the rotary knob by means of snap-on connections.

Against this background, an object of the present invention is to provide an improved household appliance.

Accordingly, a household appliance, in particular a household cooking appliance, is proposed. The household appliance comprises an operating element for operating the household appliance, the operating element comprising a rotatable actuating shaft for actuating the operating element, a rotary knob and a torque transmission device arranged between the actuating shaft and the rotary knob for transmitting a torque from the rotary knob to the actuating shaft, the torque transmission device being connected in a rotationally fixed manner the actuating shaft and the rotary knob is connected, the rotary knob having an engagement section and the torque transmission device having a counter-engagement section into which the engagement section has a positive fit engages, and wherein the engagement portion and the counter-engagement portion are formed such that an insertion force for attaching the rotary knob to the torque transmission device is smaller than a withdrawal force for removing the rotary knob from the torque transmission device. The engagement section has a first contact surface that is inclined at a first angle of inclination to an axis of rotation of the actuating shaft, and the counter-engagement section has a second contact surface that is inclined at a second angle of inclination to the axis of rotation, the first contact surface contacting the second contact surface when the rotary knob is pulled off the torque transmission device.

Since the rotary knob has the engagement section and the torque transmission device has the corresponding counter-engagement section, the rotary knob can be connected to the torque transmission device in the sense of a tongue and groove connection. An additional component in the form of a leaf spring is therefore not necessary. Both the pull-off force and the push-on force can be influenced in a targeted manner by a corresponding structural design of the engagement section and the counter-engagement section that corresponds thereto. In this way, corresponding requirements can be met that define the pull-off force, the push-on force and the difference between the two forces.

The operating element, the rotary knob and the torque transmission device are preferably part of an actuating device of the household appliance. The household appliance can include several such operating devices. The control element preferably comprises a base body in which the actuating shaft is rotatably mounted. For example, electronic components of the control element can be provided in the base body. The control element can be a rotary switch, a potentiometer or the like, for example, or a gas valve. The rotary knob is preferably a plastic component, in particular a plastic injection molded component. The torque transmission device is preferably also a plastic component, preferably a plastic injection molded component. The torque transmission device can be designed in one piece or in multiple pieces. The fact that the torque transmission device is arranged between the rotary knob and the actuating shaft means that the torque transmission device is arranged axially between the rotary knob and the actuating shaft, viewed along an axis of rotation of the actuating shaft. Of the Rotary knob is preferably a component that is separate from the torque transmission device.

The engagement section has a first contact surface that is inclined at a first angle of inclination to an axis of rotation of the actuating shaft, and the counter-engagement section has a second contact surface that is inclined at a second angle of inclination to the axis of rotation, the first contact surface contacting the second contact surface when the rotary knob is pulled off the torque transmission device.

With the help of the design of the angle of inclination, the pull-off force can thus be precisely defined. The first angle of inclination and the second angle of inclination can each be, for example, between 35° and 55°, preferably between 40° and 50°, more preferably 45°. The first contact surface and the second contact surface can each run around the rotary knob and/or the torque transmission device in the form of a ring. Alternatively, the first contact surface and the second contact surface can also run in a straight line.

According to a further embodiment, the first angle of inclination and the second angle of inclination are of the same size.

The first angle of inclination and the second angle of inclination can also be of different sizes. As a result, the pull-off force can be set precisely.

According to a further embodiment, the engagement section has a first radius surface facing away from the first contact surface and arranged closer to the operating element when viewed along the axis of rotation, and the counter-engaging section has a second radius surface arranged averted from the second contact surface and arranged closer to the operating element when viewed along the axis of rotation.

The first radius surface and the second radius surface can each encircle the rotary knob and/or the torque transmission device in a ring shape. Alternatively, the first radius surface and the second radius surface can also be straight.

According to a further embodiment, a radius of the first radius surface and a radius of the second radius surface are of the same size.

Alternatively, the radius of the first radius surface and the radius of the second radius surface can also be of different sizes.

According to a further embodiment, the torque transmission device has at least one flat torque transmission surface and the rotary knob has at least one flat mating surface which corresponds to the at least one torque transmission surface and on which the at least one torque transmission surface for transmitting the torque from the rotary knob to the torque transmission device rests.

In the present case, a flat surface is to be understood as a surface that spans a plane. In particular, such a flat surface is not curved. Two such torque transmission surfaces are preferably provided, which are arranged at a distance from one another and parallel to one another. Accordingly, are also preferred two mating surfaces corresponding thereto are provided which are spaced apart and positioned parallel to one another.

According to a further embodiment, the at least one torque transmission surface has a slot and the at least one counter surface has a web which engages in the slot in a form-fitting manner.

That is, the web extends out of the mating surface in the direction of the torque transmission surface. In particular, the slot divides the torque transmission surface into two surfaces. This means that the rotary knob cannot be mounted incorrectly on the torque transmission device. In this way, incorrect assembly can be ruled out.

According to a further embodiment, the engagement portion is a web running annularly around the rotary knob and the counter-engagement portion is a groove running annularly around the torque transmission device.

The web can be interrupted, for example, by the two mating surfaces. In particular, the groove forming the counter-engagement section can also be interrupted in the region of the torque transmission surfaces.

According to a further embodiment, the torque transmission device is designed as a two-component injection-molded part, at least with a housing that accommodates the torque transmission device at least in sections.

The torque transmission device and the housing accommodating it are preferably produced in particular in an assembly injection molding process. That is, the torque transmission device is rotatably accommodated to the housing.

According to a further embodiment, the torque transmission device has an axle element and an axle sleeve which is non-rotatable with the axle element and linearly displaceable relative to it, the axle element being non-rotatably connected to the actuating shaft and the rotary knob being non-rotatably connected to the axle sleeve.

In other words, in this case the torque transmission device is designed in two parts and includes the axle element and the axle sleeve. The axle element and the axle sleeve are preferably designed as plastic injection molded components. In particular, the axle element is slipped onto the actuating shaft and the axle sleeve is slipped onto the axle element. A spring device can be provided between the axle sleeve and the axle element. Furthermore, the axle element can also have a toothed rack with which a rotary damper engages in order to dampen the linear movement of the axle sleeve relative to the axle element. Furthermore, the axle element can also have a link guide together with a sliding block. For this purpose, a groove for the sliding block is preferably provided on the axle element. The groove can be heart-shaped.

According to a further embodiment, the rotary knob can be lowered at least in sections into a housing with the aid of a linear displacement of the axle sleeve relative to the axle element.

This means that the rotary knob can be pressed into the housing, and it locks in the pressed-in state with the aid of the link guide mentioned above. Pressing the rotary knob again releases the locking mechanism and the rotary knob is pushed out of the housing again with the help of the spring element. The rotary damper dampens the movement of the knob.

According to a further embodiment, the counter-engagement section is provided on the axle sleeve.

In this case, the counter-engagement section preferably runs perpendicularly to the axis of rotation of the actuating shaft.

According to a further embodiment, the axle sleeve has a flat surface with at least one web extending out of the surface, the counter-engagement section being a groove provided on the at least one web.

The surface is preferably arranged perpendicular to the at least one torque transmission surface. The axle sleeve is preferably rectangular in cross section. In particular, the groove breaks through the web.

According to a further embodiment, two webs are provided which are spaced apart from one another and run parallel to one another.

The number of webs is arbitrary. Only one web or more than two webs can also be provided. The webs preferably run along the axis of rotation of the actuating shaft. The counter-engagement section preferably breaks through the two webs.

According to a further embodiment, the actuating shaft, the rotary knob and the torque transmission device are designed as separate components.

In particular, the axle element and the axle sleeve are also designed as separate components.

Other possible implementations of the household appliance also include combinations of features or embodiments described above or below with regard to the exemplary embodiments that are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the household appliance.

Fig. 1

zeigt eine schematische Ansicht einer Ausführungsform eines Haushaltsgeräts;

Fig. 2

zeigt eine schematische Explosionsansicht einer Ausführungsform einer Bedienvorrichtung für das Haushaltsgerät gemäß Fig. 1;

Fig. 3

zeigt eine schematische perspektivische Explosionsansicht der Bedienvorrichtung gemäß Fig. 2;

Fig. 4

zeigt eine schematische Schnittansicht der Bedienvorrichtung gemäß Fig. 2;

Fig. 5

zeigt die Detailansicht V gemäß Fig. 4;

Fig. 6

zeigt eine schematische perspektivische Ansicht einer Ausführungsform einer Drehmomentübertragungseinrichtung für die Bedienvorrichtung gemäß Fig. 2;

Fig. 7

zeigt eine weitere schematische perspektivische Explosionsansicht der Bedienvorrichtung gemäß Fig. 2;

Fig. 8

zeigt eine schematische perspektivische Ansicht einer weiteren Ausführungsform einer Bedienvorrichtung für das Haushaltsgerät gemäß Fig. 1;

Fig. 9

zeigt eine schematische Vorderansicht der Bedienvorrichtung gemäß Fig. 8;

Fig. 10

zeigt eine schematische Schnittansicht der Bedienvorrichtung gemäß der Schnittlinie X-X der Fig. 9;

Fig. 11

zeigt die Detailansicht XI gemäß Fig. 10;

Fig. 12

zeigt eine schematische perspektivische Explosionsansicht der Bedienvorrichtung gemäß Fig. 8; und

Fig. 13

zeigt eine schematische perspektivische Ansicht einer Ausführungsform einer Achshülse für die Bedienvorrichtung gemäß Fig. 8.

Further advantageous configurations and aspects of the household appliance are the subject matter of the subclaims and the exemplary embodiments of the household appliance described below. The household appliance is explained in more detail below on the basis of preferred embodiments with reference to the enclosed figures.

1

shows a schematic view of an embodiment of a household appliance;

2

shows a schematic exploded view of an embodiment of an operating device for the household appliance according to FIG 1 ;

3

shows a schematic perspective exploded view of the operating device according to FIG 2 ;

4

shows a schematic sectional view of the operating device according to FIG 2 ;

figure 5

shows the detailed view V according to 4 ;

6

shows a schematic perspective view of an embodiment of a torque transmission device for the operating device according to FIG 2 ;

7

shows a further schematic perspective exploded view of the operating device according to FIG 2 ;

8

shows a schematic perspective view of a further embodiment of an operating device for the household appliance according to FIG 1 ;

9

shows a schematic front view of the operating device according to FIG 8 ;

10

shows a schematic sectional view of the operating device according to section line XX 9 ;

11

shows the detailed view XI according to 10 ;

12

shows a schematic perspective exploded view of the operating device according to FIG 8 ; and

13

shows a schematic perspective view of an embodiment of an axle sleeve for the operating device according to FIG 8 .

Elements that are the same or have the same function have been provided with the same reference symbols in the figures, unless otherwise stated.

1 shows a schematic view of a household appliance 1. The household appliance 1 is in particular a household cooking appliance, such as an electric stove or a gas stove. However, the domestic appliance 1 can also be designed, for example, for the care of items of laundry and can be a washing machine or a tumble dryer, for example. Likewise, the household appliance 1 can also be used, for example, for storing and preserving food, for example a refrigerator or a freezer or a combined fridge-freezer. Likewise, the household appliance 1 can also be another type of household cooking appliance, for example a microwave cooking appliance or a steam cooking appliance.

The household appliance 1 comprises a housing 2 on which a door 3 is pivotably attached. The door 3 can include a handle 4 . A receiving space for food, in which it can be prepared, can be closed by the door 3 . The household appliance 1 also includes an operating and display device 5. The operating and display device 5 includes a display unit 6, for example an LCD display, and several, for example two, operating devices 7. However, the number of operating devices 7 is arbitrary. For example, a temperature of a hotplate or an oven of the household appliance 1 can be set with the aid of each operating device 7 . The display unit 6 and the operating devices 7 are mounted on a control panel 8 of the household appliance 1 .

the 2 shows a schematic exploded view of an embodiment of an operating device 7, the 3 shows a schematic perspective exploded view of the operating device 7, the 4 shows a schematic sectional view of the operating device 7, and the figure 5 shows the detailed view V according to FIG 4 . The following will refer to the Figures 2 to 5 referenced at the same time.

The operating device 7 includes an operating element 9 for operating the household appliance 1. For example, the operating element 9 can be used to set a temperature of a hotplate or an oven of the household appliance 1. The operating element 9 can be a rotary switch, a potentiometer or a gas valve, for example. The operating element 9 comprises a base body 10 which, for example, accommodates electronic components of the operating element 9 . An actuating shaft 11 is rotatably mounted in the base body 10 . The control element 9 can be actuated with the aid of the actuating shaft 11 . The actuating shaft 11 can have a lateral flattening, for example. However, the actuating shaft 11 can have any desired geometry in cross section. The operating shaft 11 is about an axis of rotation D relative to the base body 10 rotatable. The axis of rotation D can also be a center or axis of symmetry of the operating device 7 .

In addition to the operating element 9, the operating device 7 comprises a housing 12, in which the operating element 9 can be accommodated at least in sections. The housing 12 is preferably a plastic injection molded component. The housing 12 has, as in the 4 shown, a preferably rotationally symmetrical to the axis of rotation D receiving portion 13 which receives a torque transmission device 14. The torque transmission device 14 is preferably designed as a plastic injection-molded component. In particular, the housing 12 and the torque transmission device 14 are embodied as separate components, which, however, are manufactured in an assembly injection molding process, in particular in a two-component injection molding process, in such a way that the torque transmission device 14 is accommodated in the housing 12 and is rotatably mounted about the axis of rotation D. The torque transmission device 14 has a cylindrical base section 15 which is received in the receiving section 13 of the housing 12 .

Furthermore, the torque transmission device 14 includes a receiving section 16 for receiving the actuating shaft 11. The actuating shaft 11 is received in the receiving section 16 in such a way that the torque transmission device 14 is connected to the actuating shaft 11 in a torque-proof manner. This can be achieved, for example, in that a lateral flattening is provided on the actuating shaft 11, in which the receiving section 16 engages in a form-fitting manner. A form-fitting connection is created by at least two connection partners engaging in one another or behind, in this case the receiving section 16 of the torque transmission device 14 and the actuating shaft 11.

A groove 17 running annularly around the torque transmission device 14 adjoins the base section 15 . An engagement section 18 protruding into the receiving section 13 of the housing 12 positively engages in this ring-shaped circumferential groove 17 . As a result, the torque transmission device 14 is fixed linearly along the axis of rotation D and can be rotated about the axis of rotation D. A peripheral collar 19 of the torque transmission device 14 adjoining the groove 17 bears against the engagement section 18 at the front.

The operating device 7 also includes a rotary knob 20 , with the torque transmission device 14 being arranged between the rotary knob 20 and the actuating shaft 11 when viewed along the axis of rotation D. The rotary knob 20 is connected to the torque transmission device 14 in a torque-proof manner. That is, with the aid of the torque transmission device 14, a torque M ( 3 ) for actuating the operating element 9 are transmitted. The torque M can be oriented clockwise or counterclockwise. The rotary knob 20 comprises a tubular receiving section 21 in which the torque transmission device 14 can be accommodated at least in sections. Provided on the inside circumferentially on the receiving section 21 is an engagement section 22 in the form of a web which runs annularly around the receiving section 21 . Two such engagement sections 22, 23, in particular a first engagement section 22 and a second engagement section 23, are preferably provided.

The torque transmission device 14 comprises counter-engagement sections 24, 25 corresponding to the engagement sections 22, 23. A first counter-engagement section 24 and a second counter-engagement section 25 are provided. The counter-engagement sections 24, 25 are each designed as a ring-shaped groove running around the torque transmission device 14. The engagement sections 22, 23 are designed to engage in a form-fitting manner in the counter-engagement sections 24, 25 in order to connect the rotary knob 20 to the torque transmission device 14 in a form-fitting manner. The engagement sections 22, 23 and the counter-engagement sections 24, 25 are designed in such a way that an attachment force Fauf ( 4 ) for attaching rotary knob 20 to torque transmission device 14 is smaller than a pull-off force Fab for removing rotary knob 20 from torque transmission device 14 .

A suitable geometric configuration of the engagement sections 22, 23 and the counter-engagement sections 24, 25 can ensure that the attachment force Fauf is smaller than the withdrawal force Fab. For this purpose, the respective engagement portion 22, 23, as in the figure 5 shown, a first annular circumferential contact surface 26 inclined at a first angle of inclination α1 to the axis of rotation D of the actuating shaft 11 and the respective counter-engaging section 24, 25 has a second contact surface 27 inclined at a second angle of inclination α2 to the axis of rotation D. The first contact surface makes contact with 26 the second contact surface 27 when the rotary knob 20 is pulled off the torque transmission device 14. The angles of inclination α1, α2 are preferably the same. Alternatively, the angles of inclination α1, α2 can also be of different sizes, so that the pull-off force Fab can be set as desired.

The respective engagement sections 22 , 23 have a first radius surface 28 which faces away from the first contact surface 26 and is arranged closer to the operating element 9 when viewed along the axis of rotation D. The corresponding counter-engagement section 24, 25 accordingly has a second radius surface 29 which faces away from the second contact surface 27 and is arranged closer to the operating element 9 when viewed along the axis of rotation D. Radii R28, R29 of the two radius surfaces 28, 29 are preferably of the same size. However, the radii R28, R29 can also be of different sizes.

The torque transmission device 14 comprises at least one, but preferably two, flat torque transmission surfaces 30, 31 ( 6 ), and the turning knob 20 has at least one, but preferably two, corresponding to the torque transmission surfaces 30, 31 of the torque transmission device 14, flat mating surfaces 32, 33 ( 3 ) on. To transmit the torque M from the rotary knob 20 to the torque transmission device 14, the torque transmission surfaces 30, 31 are in contact with the corresponding mating surfaces 32, 33.

The torque transmission surfaces 30, 31 are preferably spaced apart and positioned parallel to each other. Likewise, the mating surfaces 32, 33 are spaced apart and positioned parallel to each other. At least one of the torque transmission surfaces 30, 31, for example the torque transmission surface 30, is slotted using a slot 34. A web 35 provided on the corresponding mating surface 32 engages in the slot 34 in a form-fitting manner. In this way, incorrect assembly of the rotary knob 20 can be prevented.

As the 7 shows in a further schematic exploded view of the operating device 7, openings or bores 36 are provided on the operating panel 8, on each of which such an operating device 7 can be mounted.

the 8 shows a schematic perspective view of a further embodiment of an operating device for the household appliance 1 according to FIG 1 . the 9 shows a schematic front view of the operating device 7, the 10 shows a schematic sectional view of the operating device 7 along the line XX of FIG 9 , the 11 shows the detailed view XI according to FIG 10 , and the 12 shows a schematic perspective exploded view of the operating device 7. In the following, the Figures 8 to 12 referenced at the same time.

The aforementioned control element 9 is in the Figures 8 to 12 Not shown. The operating device 7 comprises a two-part housing 12 which can be formed from an upper shell 37 and a lower shell 38 which are clipped together. The operating element 9 can also be arranged in the housing 12 . The operating device 7 also does not comprise a one-piece but a two-piece torque transmission device 14 which has an axle element 39 which is connected to the actuating shaft 11 in a torque-proof manner and has an axle sleeve 40 fitted onto the axle element 39 . The axle element 39 is connected to the actuating shaft 11 in a rotationally fixed manner, and a rotary knob 20 of the operating device 7 , as already described, is connected in a rotationally fixed manner to the axle sleeve 40 . The axle element 39 comprises a toothed rack 41 on the upper side, into which a rotary damper (not shown) engages in a form-fitting manner.

A guide groove 42 is provided on the underside of the axle element 39 , facing away from the toothed rack 41 . The guide groove 42 can be part of a link guide. This link guide also includes a link block 43 which can be mounted in the axle sleeve 40 and which engages in the guide groove 42 . The guide groove 42 can be heart-shaped. The axle element 39 also includes a receiving section 16 ( 10 ) for receiving the actuating shaft 11 and a receiving section 44 for receiving a spring element 45. The spring element 45 is, for example, a cylinder spring, in particular a compression spring. The spring element 45 is arranged between the axle element 39 and the axle sleeve 40 . For this purpose, the axle sleeve 40 comprises a receiving section 46 in which the spring element 45 is received.

The axle sleeve 40 can be displaced relative to the axle element 39 along an axis of rotation D as previously described. As a result, the rotary knob 20 can be sunk into the housing 12 . With the help of the rotary damper, not shown, an extension of the knob 20 are damped out of the housing. The axle element 39 can have two webs 47 ( 12 ) have, with the help of which the axle element 39 is linearly guided on the axle sleeve 40 . The axle sleeve 40 can have corresponding receiving grooves for this purpose. The axle sleeve 40 also has two torque transmission surfaces 30, 31 ( 13 ) on which corresponding mating surfaces 32, 33 are assigned to the rotary knob 20. The mating surfaces 32, 33 are in the Figures 8 to 12 Not shown. However, the mating surfaces 32, 33 are analogous to that in FIG 3 rotary knob 20 shown is provided.

Furthermore, the rotary knob 20 includes an engagement portion 48 ( 11 ) and the axle sleeve 40 has a counter-engagement section 49 corresponding thereto, in which the engagement section 48 engages in a form-fitting manner. The engagement section 48 and the counter-engagement section 49 are not designed as annular grooves or annular webs, but on the axle sleeve 40 there is a surface 50 arranged perpendicularly to the torque transmission surface 30, 31 ( 13 ) intended. Two webs 51, 52, which are arranged parallel to one another and spaced apart from one another, extend out of this surface 50 and are interrupted by the counter-engagement section 49 designed as a groove.

Analogous to the representation according to figure 5 includes the engagement portion 48, as in FIG 11 shown, a first contact surface 53, and the counter-engagement portion 49 includes a corresponding second contact surface 54. Accordingly, the engagement portion 48 includes a first radius surface 55, and the counter-engagement portion includes a corresponding second radius surface 56. Inclination angles α1, α2 of the contact surfaces 53, 54 are preferably the same size. Radii R55, R56 of the radius surfaces 55, 56 are preferably of the same size.

Due to the use of the engagement section 22, 23, 48 and the corresponding counter-engagement section 24, 25, 49, a leaf spring can be dispensed with. This reduces the material and assembly costs. Fluctuating tolerances of the leaf spring due to production also no longer have to be taken into account. The attachment force Fauf and the withdrawal force Fab can be better matched to one another by better matching the respective counter-engagement section 24, 25, 49 and the engagement section 22, 23, 48. The variation in the pull-off force Fab can occur at operating temperature be narrowed down much better. A process-reliable magnitude and constancy of the pull-off force Fab can thus be achieved.

Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

Reference signs used:

1

household appliance

2

Housing

3

door

4

handle

5

Operating and display device

6

display unit

7

operating device

8th

control panel

9

control element

10

base body

11

operating shaft

12

Housing

13

recording section

14

torque transmission device

15

base section

16

recording section

17

groove

18

engagement section

19

Federation

20

knob

21

recording section

22

engagement section

23

engagement section

24

counter engagement section

25

counter engagement section

26

contact surface

27

contact surface

28

radius surface

29

radius surface

30

torque transmission area

31

torque transmission area

32

counter surface

33

counter surface

34

slot

35

web

36

drilling

37

Upper shell

38

bottom shell

39

axis element

40

axle sleeve

41

rack

42

guide groove

43

sliding block

44

recording section

45

spring element

46

recording section

47

web

48

engagement section

49

counter engagement section

50

Surface

51

web

52

web

53

contact surface

54

contact surface

55

radius surface

56

radius surface

D

axis of rotation

fof

insertion force

Fab

pull force

M

torque

R28

radius

R29

radius

R55

radius

R56

radius

α1

angle

α2

angle

Claims (14)

1. Household appliance (1), in particular household cooking appliance, having an operating element (9) for operating the household appliance (1), wherein the operating element (9) comprises a rotatable actuation shaft (11) for actuating the operating element (9), a rotary knob (20) and a torque transmission device (14) arranged between the actuation shaft (11) and the rotary knob (20) for transmitting a torque (M) from the rotary knob (20) to the actuation shaft (11), wherein the torque transmission device (14) is connected in a torque-proof manner with the actuation shaft (11) and the rotary knob (20), wherein the rotary knob (20) has an engaging portion (22, 23, 48) and the torque transmission device (14) has a counter engaging portion (24, 25, 49), into which the engaging portion (22, 23, 48) engages in a form-fit manner, wherein the engaging portion (22, 23, 48) and the counter engaging portion (24, 25, 49) are embodied so that an attachment force (Fauf) for attaching the rotary knob (20) to the torque transmission device (14) is less than a pull-off force (Fab) for removing the rotary knob (20) from the torque transmission device (14), characterised in that the engaging portion (22, 23, 48) has a first contact surface (26, 53) inclined at a first angle of inclination (α1) with respect to an axis of rotation (D) of the actuation shaft (11) and the counter engaging portion (24, 25, 49) has a second contact surface (27, 54) inclined at a second angle of inclination (α2) with respect to the axis of rotation (D), and wherein the first contact surface (26, 53) contacts the second contact surface (27, 54) when the rotary knob (20) is removed from the torque transmission device (14).
2. Household appliance according to claim 1, characterised in that the first angle of inclination (α1) and the second angle of inclination (α2) are the same size.
3. Household appliance according to claim 1 or 2, characterised in that the engaging portion (22, 23, 48) has a first radius surface (28, 55) facing away from the first contact surface (26, 53) and viewed along the axis of rotation (D) arranged closer to the operating element (9) and the counter engaging portion (24, 25, 49) has a second radius surface (29, 56) facing away from the second contact surface (27, 54) and viewed along the axis of rotation (D) arranged closer to the operating element (9).
4. Household appliance according to claim 3, characterised in that a radius (R28, R55) of the first radius surface (28, 55) and a radius (R29, R56) of the second radius surface (29, 56) are the same size.
5. Household appliance according to one of claims 1 - 4, characterised in that the torque transmission device (14) has at least one planar torque transmission surface (30, 31) and the rotary knob (20) has at least one planar counter surface (32, 33) which corresponds to the at least one torque transmission surface (30, 31), on which counter surface the at least one torque transmission surface (30, 31) rests for transmitting the torque (M) from the rotary knob (20) to the torque transmission device (14).
6. Household appliance according to claim 5, characterised in that the at least one torque transmission surface (30, 31) has a slot (34) and the at least one counter surface (32, 33) has a web (35) which engages in a form-fit manner into the slot (34).
7. Household appliance according to one of claims 1 - 6, characterised in that the engaging portion (22, 23) is a web which circulates in an annular manner about the rotary knob (20) and the counter engaging portion (24, 25) is a groove which circulates in an annular manner about the torque transmission device (14).
8. Household appliance according to one of claims 1 - 7, characterised in that the torque transmission device (14) together with a housing (12) receiving the torque transmission device (14) at least in sections is embodied as a two-component injection moulded part.
9. Household appliance according to one of claims 1 - 5, characterised in that the torque transmission device (14) has an axle element (39) and an axle sleeve (40) which can be connected in a torque-proof manner with the axle element (39) and can be displaced linearly hereto, wherein the axle element (39) is connected in a torque-proof manner with the actuation shaft (11) and the rotary knob (20) is connected in a torque-proof manner with the axle sleeve (40).
10. Household appliance according to claim 9, characterised in that the rotary knob (20) can be lowered at least in sections into a housing (12) with the aid of a linear displacement of the axle sleeve (40) relative to the axle element (39).
11. Household appliance according to claim 9 or 10, characterised in that the counter engaging portion (49) is provided on the axle sleeve (40).
12. Household appliance according to claim 11, characterised in that the axle sleeve (40) has a planar surface (50) with at least one web (51, 52) which extends out of the surface (50), wherein the counter engaging portion (49) is a groove provided on the at least one web (51, 52).
13. Household appliance according to claim 12, characterised in that two webs (51, 52) which are arranged at a distance from one another and run parallel to one another are provided.
14. Household appliance according to one of claims 1 - 13, characterised in that the actuation shaft (11), the rotary knob (20) and the torque transmission device (14) are embodied as components which are separate from one another.

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