Household appliance with opening device

Abstract

The invention relates to a household appliance comprising an interior space, a closure element which reversibly and at least partially closes the interior space, and an opening device with a drive unit which provides a torque, a gear arrangement which is operatively connected to the drive unit, and a tappet element which is operatively connected to the gear arrangement, wherein the gear arrangement in operative connection with the tappet element converts the torque provided by the drive unit into a force which acts linearly in one direction and which is acted upon by the tappet element by the tappet element, wherein the force on the closure element assumes different values ​​for at least two different positions of the tappet element at a constant torque.The tappet element is at least partially designed as a rack, wherein the rack meshes with a first gear of the gear assembly at least when the closure element is opened. Furthermore, the first gear has a spiral pitch line, wherein the spiral pitch line provides different transmission ratios between the first gear and the rack for at least two different rotational positions of the first gear.

Description

[0001] The invention relates to a household appliance with an opening device for opening a closure element. The opening device comprises a plunger element, a gear arrangement, and a drive unit.

[0002] Many household appliances such as washing machines, dishwashers, ovens, refrigerators, etc. have locking elements such as doors or drawers to lock the interior of the appliance. To make opening and / or closing easier for the user and to allow moisture or warm air to escape from the interior, such household appliances are equipped with door openers. Such door openers usually consist of a handle that is driven by an electric motor and mechanically pushes the door open. Since these household appliances are usually also equipped with locks to keep the doors closed, opening the doors requires increased force at the beginning of the opening process in order to overcome the resistance of the lock. Likewise, when closing the door, increased force may be required to overcome the resistance of the lock at the end of the closing process.To overcome these resistances, either a relatively large electric motor with a correspondingly high torque would be necessary, or a gear ratio that converts a small torque at high speed into a large torque at low speed. Conventional door openers have a small electric motor that drives a pinion and ultimately a rack with a fixed gear ratio. Another door opener of this type is known from patent DE 10 2019 128 526 B3.

[0003] Since the electric motor is usually supplied with constant current to save the cost of a variable voltage or frequency converter, and the gear ratio is fixed, this means that the small electric motor can initially provide sufficient power to overcome the resistance of the shutter, but then, due to the fixed gear ratio, the rack is moved very slowly by the low speed of the pinion.

[0004] It is therefore an object of the invention to provide a household appliance with an opening device which overcomes the disadvantages of the prior art and thus reduces space requirements and costs and increases user comfort.

[0005] According to the invention, a household appliance is provided that comprises an interior space, a closure element that reversibly and at least partially closes the interior space, and an opening device. The opening unit has a drive unit that provides a torque, a gear assembly operatively connected to the drive unit, and a plunger element operatively connected to the gear assembly. The gear assembly, in operative connection with the plunger element, converts the torque provided by the drive unit into a linear, unidirectional force that is applied to the closure element by the plunger element.In this case, the force on the closure element assumes different values ​​for at least two different positions of the tappet element at constant torque, wherein the tappet element is at least partially designed as a rack, wherein the rack is in meshing engagement with a first gear of the gear arrangement at least when the closure element is opened, wherein the first gear has a spiral pitch line, wherein different transmission ratios are present between the first gear and the rack due to the spiral pitch line for at least two different rotational positions of the first gear.

[0006] Household appliances include all electrical appliances used in private households, such as ovens, microwave ovens, dishwashers, refrigerators, freezers, convection ovens, combi steamers, dehydrators, washing machines, dryers, and similar.

[0007] These household appliances have a body that partially encloses an interior of the household appliance. One or more locking elements, such as tilting doors, pivoting doors, sliding doors, drawers, or flaps, are provided to completely or at least partially close the interior. To keep the locking element closed, a lock can also be provided, which provides increased initial resistance when opening the locking element and increased final resistance when closing the locking element. Alternatively or additionally, such resistance can also result from a pressure difference between the interior and the surroundings of the household appliance.

[0008] The interior of a household appliance primarily serves as a work and / or storage space. Examples of work spaces include laundry rooms, dishwashing rooms, drying rooms, or cooking rooms. Examples of storage spaces include refrigerated or freezer rooms.

[0009] According to the invention, the household appliance has an opening device. This is preferably arranged in the body of the household appliance, more preferably in a side wall, a ceiling or a floor. The opening device is preferably directly adjacent to the closure element. The opening device is designed to at least partially, preferably completely, open the closure element of the household appliance. For this purpose, the opening device has a drive unit that provides a torque. The drive unit is preferably an electric motor, wherein the drive unit is connected to a control unit. The drive unit is preferably constantly energized, for example operated with a constant voltage and / or frequency, in order to avoid expensive circuits. However, this constant energization requires that the speed of the drive unit is also constant during operation.

[0010] According to a preferred embodiment, the household appliance is alternatively or additionally designed to provide a means for reaching the closure element. In handle-free household appliances or pieces of furniture, it is not possible for the user to open the closure element by pulling on a handle. Therefore, such household appliances or pieces of furniture have mechanisms for reaching the closure element, wherein the closure element is opened until a user can grasp and open the closure element. Such a handle-free household appliance preferably has a sensor unit with a sensor that emits a signal in response to a user action, for example pressure exerted by a user, contact made by the user and / or a gesture performed by the user. An acoustic sensor that detects a noise made by the user would also be possible.The signal emitted by the sensor unit is forwarded to the control unit, which controls the drive unit based on the signal, thus triggering the closure element to be reached. Preferably, the control unit can also trigger the opening device to close based on a signal from the sensor unit, whereby a closure element is completely closed. Preferably, the opening device closes the closure element completely, whereby the user does not completely close the closure element. Advantageously, the closure element is reached quickly and in a user-friendly manner by the household appliance according to the invention.

[0011] In addition to the drive unit, the opening device has a gear arrangement. The gear arrangement translates the torque or speed output by the drive unit. For this purpose, the drive unit and gear unit are operatively connected. The gear ratio converts a lower torque at high speed into a higher torque at low speed and / or vice versa. This conversion can occur linearly, abruptly, logarithmically, exponentially, sinusoidally, or according to another mathematical function, depending on the distance traveled by the plunger element.

[0012] In addition, the opening device preferably comprises a rod-shaped plunger element. The plunger element is operatively connected to the gear unit and serves to convert a rotary movement, which is transmitted from the drive unit to the gear arrangement, into a linear movement in one direction through interaction with the gear arrangement. The plunger element can be moved back and forth between a retracted starting position and an extended end position. In the starting position, the plunger element disappears at least partially into the body of the household appliance so that the closure element can be completely closed. When opened, the plunger element is moved towards the end position. In doing so, it pushes and / or presses against the closure element and thereby applies a force to the closure element, which opens the closure element.Preferably, the closure element opens only as long as the plunger element is moving. Preferably, the closure element is fully or partially open in an end position of the plunger element.

[0013] According to the invention, the force on the closure element assumes different values ​​for at least two different positions of the plunger element, with a constant torque output by the drive unit.

[0014] According to the invention, the tappet element is at least partially designed as a toothed rack, wherein the toothed rack is in meshing engagement with a first gear of the gear arrangement at least when the closure element is opened.

[0015] Preferably, the drive unit, the gear assembly, and the plunger element are at least partially arranged in a housing of the opening device. More preferably, the drive unit and the gear assembly are arranged entirely within the housing. Furthermore, the housing has an opening through which the plunger element can be moved.

[0016] Preferably, the housing is attached to the body of the household appliance.

[0017] According to the invention, the first gear has a spiral pitch line, wherein the spiral pitch line provides different gear ratios between the first gear and the rack for at least two different rotational positions of the first gear.

[0018] Using a pitch circle or pitch line, two gears are represented in simplified form and described as cylinders rolling against each other, so-called pitch cylinders. If the first gear has a spiral, particularly logarithmic, pitch line, the gear ratio between the rack and the first gear changes depending on the angle of rotation of the first gear. To maintain the meshing engagement between the first gear and the rack, the rack must be shaped to match the pitch line of the first gear.

[0019] According to a particularly preferred embodiment, in a free-rotating position, the first gear is rotated so far that the first gear and the rack leave the meshing engagement, wherein in the free-rotating position no power is transmitted from the first gear to the tappet element.

[0020] If the first gear is spiral, the radius of the gear depends on the angle of rotation and increases logarithmically with the angle of rotation. However, since the angle of rotation is limited to 360°, there is a jump between a minimum and a maximum radius of the first gear. This jump can be exploited to release the meshing engagement between the first gear and the rack by over-rotating the first gear. Over-rotating means that the first gear continues to rotate beyond the point at which the tappet element is maximally extended and the first gear is in meshing engagement at the maximum radius. By continuing to rotate, the radius of the first gear jumps to the minimum radius and the first gear and the rack lose their meshing engagement. The first gear assumes a free-rotating position in which no further power is transmitted between the tappet element and the first gear.The first gear and the tappet element are thus decoupled.

[0021] According to a particularly preferred embodiment, in the free-rotation position, a return stroke device transfers the plunger element into a retracted starting position.

[0022] According to a particularly preferred embodiment, the return stroke device has a spring element, wherein the spring element, when the first gear is in a free-rotating position, transfers the plunger element into the retracted starting position by means of its spring force.

[0023] By decoupling the first gear and the rack, no more force is transmitted between the two. A return stroke device can now move the plunger element from the extended end position to the retracted starting position. By means of a spring element, which is attached on the one hand to the plunger element and on the other hand to the housing of the opening device and / or to the body of the household appliance, the plunger element can be easily moved into the retracted starting position by the spring force of the spring element. For this purpose, the spring element is preferably tensioned by extending, i.e. moving the plunger element from the starting position to the end position. By relaxing the spring element, the plunger element is returned to the starting position or retracted. As an alternative to a spring element, a return stroke device comprising a magnet or a cable pull would also be conceivable.

[0024] Alternatively, or in addition to the return stroke device, the plunger element can also be moved from the extended end position to the retracted starting position by a backward movement of the drive unit, i.e., a movement opposite to a forward movement. It is also conceivable for the plunger element to be connected to the closure element so that it can not only push against the closure element but also pull on it. Such a connection should be detachable. For example, a magnetic connection, a hook, a Velcro connection, or something similar could be used as a connection.

[0025] According to a preferred embodiment, in the retracted starting position, the first gear comes into meshing engagement with the rack of the tappet element by rotating the first gear from the free-rotating position.

[0026] Preferably, it is possible to release and re-engage the meshing engagement between the gear and the rack by rotating in one direction. This allows the drive unit and / or the gear unit to be driven preferably in one direction to move the tappet element both from the starting position to the end position and vice versa, from the end position to the starting position, without having to change the direction of rotation of the drive unit. During the transition to the starting position, the first gear is preferably in a free-rotating position.

[0027] According to the invention, a household appliance is also provided to achieve the object, comprising an interior space, a closure element that reversibly and at least partially closes the interior space, and an opening device with a drive unit that provides a torque, a gear arrangement operatively connected to the drive unit, and a tappet element operatively connected to the gear arrangement, wherein the gear arrangement, in operative connection with the tappet element, converts the torque provided by the drive unit into a linear force acting in one direction, with which the closure element is acted upon by the tappet element, wherein the force on the closure element assumes different values ​​for at least two different positions of the tappet element at a constant torque, wherein the tappet element is at least partially designed as a toothed rack,The rack meshes with a first gear of the gear arrangement at least upon opening of the closure element (3), the first gear having a circular pitch line. For this embodiment, the first gear is in constant meshing engagement with the rack of the tappet element.

[0028] According to a preferred embodiment, the gear arrangement comprises a second gear and a third gear, wherein the second and the third gear each have a spiral pitch line and wherein the second and the third gear are in meshing engagement with each other.

[0029] Preferably, the second and third gears are identically designed. Additionally, their pitch circles can have the shape of a logarithmic spiral. Furthermore, the second and third gears are preferably arranged 180° out of phase.

[0030] According to a preferred embodiment, the gear arrangement comprises a second gear and a third gear, wherein the second and the third gear each have an elliptical pitch line and wherein the second and the third gear are in meshing engagement with each other.

[0031] Preferably, the second and third gears are identically constructed, each rotating around the center of their elliptical pitch lines. Alternatively, they can each rotate around one of their focal points, with the two gears being in constant meshing engagement.

[0032] According to one embodiment, the second and / or third gear rotates about a common axis with the first gear. Preferably, the first gear is connected to the second or third gear. In particular, the two connected gears rotate at the same speed.

[0033] According to the invention, to achieve the object, a household appliance is also provided, comprising an interior space, a closure element that reversibly and at least partially closes the interior space, and an opening device with a drive unit that provides a torque, a gear arrangement operatively connected to the drive unit, and a tappet element operatively connected to the gear arrangement, wherein the gear arrangement, in operative connection with the tappet element, converts the torque provided by the drive unit into a linear force acting in one direction, with which the closure element is acted upon by the tappet element, wherein the force on the closure element assumes different values ​​for at least two different positions of the tappet element at a constant torque, wherein the gear arrangement has a wheel,wherein a coupling is eccentrically connected to the wheel on the one hand and to the tappet element on the other hand, wherein the gear arrangement forms a slider crank.,

[0034] By arranging a slider crank, the deflection of the plunger element can be configured sinusoidally depending on the wheel's rotation angle. This advantageously results in the smallest change in relation to the rotation angle at the minimum and maximum deflection, resulting in the greatest force acting on the plunger element at the minimum and maximum deflection, i.e., the initial and final positions.

[0035] Further advantages, objects, and features of the present invention will become apparent from the following descriptions of the accompanying figures. Similar components may have the same reference numerals in the various embodiments.

[0036] They show: Fig. 1 is an overall view of a household appliance according to the invention in one embodiment; Fig. 2 an opening device from the prior art; Fig. 3a Parts of an opening device according to the invention with a spiral-shaped first gear; Fig. 3b-e the parts of the opening device according to Fig. 3a in different positions; Fig. 4a Parts of an opening device according to the invention with a spiral-shaped second gear and a spiral-shaped third gear; Fig. 4b the top view of the parts of the opening device according to Fig. 4a; Fig. 4c the bottom view of the parts of the opening device according to Fig. 4a; Fig. 5a Parts of an opening device according to the invention with an elliptical second gear and an elliptical third gear; Fig. 5b the bottom view of the parts of the opening device according to Fig. 5a and Fig. 6 parts of an opening device according to the invention with a sliding crank.

[0037] The Fig. 1 shows an embodiment of a household appliance 1 according to the invention. Shown here is a dishwasher 1 which encloses an interior 2 with a cuboid-shaped body 12. The interior 2 is made accessible by a closure element 3 in the form of a flap 3 for loading the interior 2. The dishwasher 1 also has a lock with which the flap 3 can be locked, thereby preventing unintentional opening of the flap 3 during a work cycle of the dishwasher 1. However, this lock ensures that an increased initial resistance must first be overcome to open the flap 3. After that, little to no force is required to open the flap 3. Immediately after a work cycle of the dishwasher 1, the interior 2 is typically filled with hot steam, which is used to dry dishes.Since the flap 3 seals the interior 2 in a watertight manner, the steam cannot escape after the operation, which can have a detrimental effect on the result of the drying process. For this reason, the dishwasher 1 comprises an opening device 4 which is arranged in the carcass ceiling of the dishwasher 1 near the door and can at least partially open the flap 3 after a operation. Alternatively, an arrangement in one of the side walls would also be conceivable, or in the case of a drawer 3 or a pivoting door 3, an arrangement in a base section of the dishwasher 1 would be conceivable. However, the opening device 4 must be in direct contact with the flap 3 via a tappet element 7 in order to be able to open it by applying mechanical force. In . Fig. 1 shows how the plunger element 7 has partially opened the flap 3. To do so, the plunger element 7 has assumed an extended end position 16.

[0038] Based on the Fig. 2 the function of the opening device 4 is explained in more detail. Fig. 2 an opening device 4 from the prior art. With the exception of the Fig. 3a to 6, the opening device 4 can be arranged according to the Fig. 2 can be adopted for an opening device 4 according to the invention. The opening device 4 comprises a housing 10 in which a drive unit 5 in the form of an electric motor 5, a gear arrangement 6 and a plunger element 7 are arranged. The plunger element 7 is designed as a long and flat rod which is received in a guide rail 11 formed by the housing 10. The guide rail 11 limits the freedom of movement of the plunger element 7, whereby only movement in the direction of movement F, indicated by the double arrow, is possible. In addition, the plunger element 7 has a section on a flat side which faces the interior of the housing and forms a toothed rack 8. A first gear 9 engages this toothed rack 8. By a rotational movement of the first gear, the plunger element 7 is thus displaced along the guide rail 11 in the direction of movement F.

[0039] In the Fig. 2 shows a retracted starting position 15, in which the plunger element 7 is maximally accommodated in the housing. In this position 15, the opening of the interior 2 of the dishwasher 1 can be completely closed by the door 3.

[0040] The first gear 9 is connected to the drive unit 5 via a gear arrangement 6. The gear arrangement 6 according to the Fig. 2 shows a fixed gear ratio, meaning the rotational speed of the first gear 9 depends only on the rotational speed of the electric motor 5. To save space and make the opening device 4 cost-effective, the gear arrangement 6 is designed such that a high speed of the electric motor 5 is translated into a low speed of the first gear 9 and thus into a low speed of the tappet element 7. Likewise, a small torque M of the electric motor 5 is translated into a large torque of the first gear 9 and thus into a large force on the tappet element 7. For this purpose, the gear arrangement 6 has at least one gear that is driven directly by the electric motor 5 by means of a pinion, a worm, or the like.

[0041] Since a low speed and a high force on the tappet element 7 are not desirable for all positions of the tappet element 7, the following figures show several embodiments that enable a variable gear ratio through a special gear arrangement 6. Variable gear ratio in this context means that, at a constant speed or constant torque M of the electric motor 5, the speed or torque of the first gear 9 can vary.

[0042] For a simpler overview, some previously shown parts of the opening device 4 or the household appliance 1 are omitted below.

[0043] The Fig. 3a to 3e show an embodiment with a spiral-shaped first gear.

[0044] The Fig. Figure 3a shows a gear assembly 6a and the tappet element 7 with a rack 8a extending obliquely to the main extension of the tappet element. The gear assembly includes a spiral first gear 9a meshing with the rack. A pinion is also shown, which is rigidly connected to the spiral first gear 9a and serves to drive the first gear 9a.

[0045] The Fig. Figure 3b shows the gear subassembly 6a with the tappet element 7 in a retracted starting position 15. The first gear 9a can rotate about the axis A1. The axis A1 is fixedly arranged in the housing 10 and thus fixedly in the body 12 of the household appliance 1. Ws indicates the pitch line of the first gear 9a. It can clearly be seen that the radius of the pitch line, or the radius of the first gear 9a, increases depending on the angle of rotation of the first gear 9a and then decreases abruptly. By rotating the first gear 9a in the direction of rotation R, the transmission ratio between the first gear 9a and the rack 8a initially increases. The shape of the rack 8a is adapted to the change in the radius of the first gear 9a.

[0046] The Fig. 3c and Fig. 3d show different positions of the tappet element 7. By the rotational movement of the first gear in the direction of rotation R, the tappet element 7 is moved in the direction of movement F. The first gear 9a and the rack 8a are constantly in meshing engagement.

[0047] The Fig. Figure 3e shows the extended end position 16, i.e., the position in which the tappet element is extended furthest. It is also clearly visible that the first gear 9a is meshing with the rack 8a with only one tooth. If the first gear 9a is now rotated further in the direction of rotation R, it leaves the meshing engagement with the rack 8a and reaches a free-rotating position not shown here. In this free-rotating position, no power is transmitted between the first gear 9a and the rack 8a.

[0048] In the Fig. 3b also shows a return stroke device 13. In this embodiment, the return stroke device 13 comprises a spring element 14 in the form of a torsion spring 14. The torsion spring 14 is connected on the one hand to one end of the plunger element 7, which is located on the side of the plunger element 7 opposite the door, and on the other hand to the housing 10 of the opening device 4. By extending the plunger element 7, the torsion spring 14 is tensioned. Fig. 3e, the torsion spring 14 is shown in a tensioned state. If the first gear 9a leaves the meshing engagement with the rack 8a, thus assuming a free-rotating position, the tappet element 7 can be moved from an extended end position 16, as in the Fig. 3e, by the restoring force of the spring 14 into the retracted starting position 15, as in the Fig. 3b. Not shown here, the return stroke device 13 may have a stop, for example a rubber stop, that limits a return stroke movement of the plunger element 7. Alternatively or additionally, the return stroke device 13 may also include a damping device that dampens a return stroke movement.

[0049] By further turning the first gear 9a in the direction of rotation R, the first gear 9a can again mesh with the rack 8a, according to Fig. 3b. The first gear 9a engages the rack 8a at its minimum toothed radius as shown in Fig. 3a and Fig. 3b shown.

[0050] Advantageously, it is therefore sufficient to rotate the first gear 9a only in one direction of rotation R in order to both retract and extend the tappet element 7.

[0051] The Fig. Figure 4a shows a further embodiment with a tappet element 7 and a gear assembly with spiral second and third gears 6b. The tappet element 7 has a straight rack 8b. Also shown are a second gear 17 and a third gear 18, the gears being designed as a spiral second gear 17a and a spiral third gear 18a.

[0052] In the Fig. Figure 4b shows a plan view of the tappet element 7 and the gear subassembly 6b. The spiral second gear 17a rotates about the first axis of rotation A1 and the spiral third gear 18a rotates about the second axis of rotation A2. The spiral pitch lines Ws of the gears are also marked. The spiral second gear 17a and the spiral third gear 18a are in constant meshing engagement and are arranged 180° out of phase. During the transition from the minimum to the maximum radius when engaging the spiral second gear 17a and the spiral third gear 18a, a gear ratio jump occurs, i.e. a sudden change from low to high gear ratio or vice versa. The two axes of rotation A1 and A2 are firmly connected to the housing and their position is unchangeable.

[0053] Fig. Figure 4c shows a bottom view of the tappet element 7 and the gear assembly 6b. The spiral second gear 17a is rigidly connected to the first gear 9, and both rotate about the first axis A1. The first gear 9 is designed as a circular first gear 9b with a circular pitch line Ws, which meshes with the rack 8b. The spiral third gear 18a is rigidly connected to a pinion, and both rotate together about the rotational axis A2. Various shapes are conceivable for the spiral pitch lines Ws, such as the Archimedean spiral, the logarithmic spiral, the hyperbolic spiral, or similar spirals. The spiral shape can also be adapted to the needs of the household appliance. The pitch line Ws can contain steps and / or offsets.

[0054] In Fig. 5a shows a tappet element 7 with a gear assembly with elliptical second and third gears 6c. The elliptical second gear 17b is fixedly connected to the circular first gear 9b, and both rotate about the first axis of rotation A1. The elliptical third gear 18b is fixedly connected to a pinion and rotates together with it about the second axis of rotation A2. In the embodiment shown, both elliptical gears 17b and 18b rotate about their center point. Alternatively, both elliptical gears 17b and 18b can also rotate about one of their respective focal points. The elliptical second gear 17b and the elliptical third gear 18b are in constant meshing engagement. Shown here, the major axis of the elliptical second gear 17b merges into the minor axis of the elliptical third gear 18b.The transmission through a gear subassembly 6c results in a sinusoidal curve for the speed and force of the plunger element 7, depending on the angle of rotation of the elliptical third gear 18b. The transmission of the gear assembly 6 is adjusted such that in a retracted starting position 15 and an extended end position 16 of the plunger element 7, the speed is minimal and the force on the plunger element 7 is maximal. Halfway between the two positions, the speed of the plunger element 7 is maximal and the force is minimal.

[0055] Fig. Figure 5b shows a top view of the tappet element 7 and the gear assembly 6c. The elliptical pitch lines We and the rotation axes A1 and A2 are marked.

[0056] A drive of the gear subassemblies 6b and 6c according to the Fig. 4 and Fig. 5 is effected via the pinion, which is driven at least indirectly by the electric motor 5.

[0057] In Fig.6 shows an embodiment with a slider crank. The tappet element 7 is designed as a push rod 7. A rod-shaped coupling 19 is rotatably connected at one end to the push rod 7 via a push rod joint 21 and at the other end to a circular crank disk 22 via a crank joint 20. The crank disk is fixedly connected to a pinion and rotates about the first axis of rotation A1. During a rotational movement in the direction of rotation R of the crank disk 22, the crank joint 20 moves along a circular path about the first axis of rotation A1. The end of the coupling 19 connected to the crank joint is moved along the circular path accordingly.By connecting the coupling 19 to the push rod 7 via the push rod joint 21 and restricting the freedom of movement of the push rod 7 by the guide rail 11 (not shown here), only the movement of the crank joint 20 along the direction of movement F of the push rod 7 is transmitted to the push rod 7. This results in a nearly sinusoidal curve for the force on the push rod 7 and the speed of the push rod 7.

[0058] The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are novel, individually or in combination, over the prior art. It is further noted that the individual figures also describe features that may be advantageous in and of themselves. The skilled person will immediately recognize that a particular feature described in a figure may be advantageous even without adopting further features from that figure. Furthermore, the skilled person will recognize that advantages may also arise from a combination of several features shown in individual or different figures. List of reference symbols 1 household appliance 2 Interior 3 locking element 4 Opening device 5 Drive unit 6 Gear arrangement 6a Gear assembly with spiral first gear 6b Gear assembly with spiral second and third gear 6c Gear assembly with elliptical second and third gear 6d Gear assembly with slider crank 7 Tappet element 8 rack 8a Inclined rack 8b Straight rack 9 First gear 9a Spiral first gear 9b Circular first gear 10 housings 11 Guide rail 12 Corpus 13 Return stroke device 14 Spring element 15 Retracted starting position 16 Extended end position 17 Second gear 17a Spiral second gear 17b Elliptical second gear 18 Third gear 18a Spiral third gear 18b Elliptical third gear 19 paddocks 20 Crank joint 21 Push rod joint 22 Crank disc F Direction of movement M Torque of the drive unit R Direction of rotation Ws Spiral pitch line Wk Circular pitch line We Elliptical pitch line A1 first axis of rotation A2 second axis of rotation

Claims

[1] Household appliance (1) comprising an interior space (2), a closing element (3) reversibly and at least partially closing the interior space (2), and an opening device (4) with a drive unit (5) providing torque, a gear arrangement (6) operatively connected to the drive unit (5), and a plunger element (7) operatively connected to the gear arrangement (6), wherein the gear arrangement (6) in operative connection with the plunger element (7) converts the torque (M) provided by the drive unit (5) into a force acting linearly in one direction (F) with which the closing element (3) is acted upon by the plunger element (7), wherein the force on the locking element (3) assumes different values ​​for at least two different positions of the plunger element (7) at constant torque (M), wherein the plunger element (7) is at least partially designed as a rack (8), wherein the rack (8) is in meshing engagement with a first gear (9) of the gear arrangement (6) at least when the locking element (3) is opened, characterized by , that the first gear has a spiral rolling line, wherein the spiral rolling line provides different gear ratios between the first gear (9) and the rack (8) for at least two different rotational positions of the first gear (9). [2] Household appliance (1) according to claim 1, characterized by, that in a free-rotating position the first gear (9) is rotated so far that the first gear (9) and the rack (8) leave the meshing engagement, whereby in the free-rotating position no force transmission takes place from the first gear (9) to the tappet element (7). [3] Household appliance (1) according to claim 2, characterized by , that in the free rotation position a return stroke device (13) transfers the plunger element (7) to a retracted starting position (15). [4] Household appliance (1) according to claim 3, characterized by , that the return stroke device (13) has a spring element (14) wherein the spring element (14), when the first gear (9) is in a free-rotating position, transfers the plunger element (7) to the retracted starting position (15) by means of its spring force. [5] Household appliance (1) according to claim 3 or 4, characterized by, that in the retracted starting position (15) by turning the first gear (9) out of the free-rotating position, the first gear (9) comes into meshing engagement with the rack (8) of the plunger element (7). [6] Household appliance (1) comprising an interior space (2), a reversibly and at least partially closing the interior space (2), and an opening device (4) with a torque-providing drive unit (5), a gear arrangement (6) operatively connected to the drive unit (5), and a plunger element (7) operatively connected to the gear arrangement (6), wherein the gear arrangement (6), in operative connection with the plunger element (7), converts the torque (M) provided by the drive unit (5) into a force acting linearly in one direction (F), with which the closing element (3) is acted upon by the plunger element (7), wherein the force on the closing element (3) assumes different values ​​for at least two different positions of the plunger element (7) at a constant torque (M), wherein the plunger element (7) is at least partially designed as a rack (8),wherein the rack (8) is in meshing engagement with a first gear (9) of the gear arrangement (6) at least when the locking element (3) is opened, characterized by , that the first gear (9) has a circular pitch line (Wk). [7] Household appliance (1) according to claim 6, characterized by , that the gear arrangement (6) has a second gear (17) and a third gear (18), wherein the second (17a) and the third gear (18a) each have a spiral rolling line (Ws), wherein the second (17a) and the third gear (18a) are in meshing engagement with each other. [8] Household appliance (1) according to claim 6, characterized by , that the gear arrangement (6) has a second gear (17) and a third gear (18), wherein the second (17b) and the third gear (18b) each have an elliptical pitch line (We), wherein the second (17b) and the third gear (18b) are in meshing engagement with each other. [9] Household appliance (1) comprising an interior space (2), a closure element (3) reversibly and at least partially closing the interior space (2), and an opening device (4) with a drive unit (5) providing torque, a gear arrangement (6) operatively connected to the drive unit (5), and a plunger element (7) operatively connected to the gear arrangement (6), wherein the gear arrangement (6) in operative connection with the plunger element (7) converts the torque (M) provided by the drive unit (5) into a force acting linearly in one direction (F) with which the closure element (3) is acted upon by the plunger element (7), wherein the force on the closure element (3) assumes different values ​​for at least two different positions of the plunger element (7) at a constant torque (M), characterized by, that the gear arrangement (6) has a wheel (22), wherein a coupling (19) is eccentrically connected on one side to the wheel (22) and on the other side to the tappet element (7), wherein the gear arrangement (6) forms a push-pull crank.

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