EP4680798A1

EP4680798A1 - Household appliance equipped with a levelling system

Info

Publication number: EP4680798A1
Application number: EP23711739.5A
Authority: EP
Inventors: Mattia ROVEDO
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2023-03-17
Filing date: 2023-03-17
Publication date: 2026-01-21
Also published as: AU2023438761A1; WO2024193792A1; CN120813737A

Abstract

The invention relates a household appliance (1) comprising an outer casing (4) having a supporting base (10) and a levelling system (50). The levelling system (50) comprises a height-adjustable levelling foot (30; 130) with a threaded shaft (32) having a plurality of external threads (34) and a nut portion (14) realized in the supporting base (10). The plurality of external threads (34) of the threaded shaft (32) comprises a first external thread (36), a second external thread (38) and one or more interposed external threads (40) comprised between the first external thread (36) and the second external thread (38). The crest (36a) of the first external thread (36) has a first radius (R1) and the crest (38a) of the second external thread (38) has a second radius (R2), wherein the first radius (R1) and the second radius (R2) are greater than the radius (Ra) of the crest (40a) of each of the interposed external threads (40).

Description

HOUSEHOLD APPLIANCE EQUIPPED WITH A LEVELLING SYSTEM

FIELD OF THE INVENTION

The present disclosure relates to a household appliance, in particular to a household appliance having a levelling system comprising one or more height- adjustable levelling feet.

BACKGROUND ART

Household appliances of known type, such dishwashers, laundry washing machines or laundry drying machines, comprise an outer casing having a supporting base equipped a plurality of height-adjustable levelling feet protruding from the underside of the supporting base for levelling/balancing the appliance.

In the context of the present description the term “household appliance” essentially means any household appliance that can be provided with a disclosed levelling system. The household appliance is therefore not limited to an appliance as cited above but can also be other type of appliances like a refrigeration appliance, a freezer appliance, a cooker, a microwave appliance, a coffee machine or the like. The household appliance is advantageously balanced by levelling the feet, in particular by levelling one or more feet that are provided at the supporting base.

A height-adjustable levelling foot of known type comprises a threaded shaft with a lower head that abuts the surface on which the appliance stands on. The threaded shaft is received in a nut portion of the supporting base. The height adjustment of the foot is obtained by rotating the foot around its axis, for example by means of a wrench.

In a typical use thereof, height adjustment action of the levelling foot/feet is carried out the first time the appliance is installed or in case of maintenance or change of place. Such action is particularly relevant during installation of bult-in appliances, such as built-in dishwashers or built-in laundry washing machines or built-in laundry drying machines.

It is important that the selected height is maintained during height adjustment. Any play between the threaded shaft of the levelling foot and the respective nut portion negatively affects the height adjustment action and/or the right balancing of the appliance.

A further issue that arises after the appliance has been levelled is that of keeping

- 1 -

SUBSTITUTE SHEET (RULE 26) the stability of the levelling system by assuring that the feet remain in a stable and fixed position as much as possible. This is particularly relevant in appliances that are frequently moved or that are subjected to movements during functioning, for example a dishwasher with movements caused by rotating spray arms or a laundry washing machine during spinning cycles causing vibrations or a laundry dying machine with a rotatable tumble causing vibrations.

It is therefore an object of the present invention to provide a levelling system for a household appliance that improves the height adjustment action of the appliance.

It is a further object of the present invention to provide a levelling system for a household appliance with improved stability compared to levelling systems of known type.

DISCLOSURE OF THE INVENTION

Applicant has found that by providing a household appliance having a levelling system comprising at least one height-adjustable levelling foot arranged on a supporting base of the appliance, wherein said foot comprises a threaded shaft having a plurality of external threads and wherein the foot is screw-coupled to a nut portion of the supporting base and by providing said plurality of external threads with crests showing different radii, it is possible to reach the mentioned objects.

In an aspect thereof the present invention relates, therefore, to a household appliance comprising an outer casing having a supporting base and a levelling system, said levelling system comprising at least one height-adjustable levelling foot arranged on said supporting base and protruding from an underside of said supporting base, said foot comprising a threaded shaft having a plurality of external threads and said supporting base comprising a nut portion comprising a hole having an internal wall comprising at least one internal thread protruding therefrom, said foot being screw-coupled to said nut portion via engagement of said threaded shaft of said foot and said nut portion of said supporting base; wherein said plurality of external threads of said threaded shaft comprises a first external thread, a second external thread and one or more interposed external threads comprised between said first external thread and said second external thread, wherein the crest of said first external thread has a first radius, the crest of said second external thread has a second radius and wherein said first radius and said second radius are greater than the radius of the crest of each of said interposed external threads.

Advantageously, the crest of the first external thread and the crest of the second external thread abut against the surface of the internal wall of the nut portion and generates an interference force that limits any unwanted movement of the foot with respect to the nut portion. The height adjustment action is therefore improved.

In a preferred embodiment, the first radius of the first external thread is equal to the second radius of the second external thread.

Advantageously, the screwing force when the foot is rotated, i.e. screwed/unscrewed into/from the nut portion, is constant or substantially constant. According to a preferred embodiment, all the crests of the interposed external threads have the same radius.

Preferably, the internal wall of the hole of the nut portion is a cylindrical inner wall. Advantageously, the friction between the first external thread and the second external thread is kept constant when the foot is rotated, i.e. screwed/unscrewed into/from the nut portion.

In a preferred embodiment, the internal wall of the hole of the nut portion comprises just one internal thread protruding therefrom.

Advantageously, by providing the internal wall with just one internal thread it is possible to simplify manufacturing of the supporting base and/or reducing manufacturing time, in particular when the supporting base is made through an injection moulding process.

According to a preferred embodiment, the threaded shaft of the foot extends along a shaft axis and the internal wall of the hole extends along a hole axis, wherein the shaft axis and the hole axis coincide when the foot is screw-coupled to the nut portion, wherein the extension of a surface of the internal wall measured along an axis parallel and coplanar to the hole axis is at least equal to the distance between the crest of the first external thread and the crest of the second external thread measured along an axis parallel and coplanar to the shaft axis.

According to a further preferred embodiment, the extension of the surface of the internal wall measured along an axis parallel and coplanar to the hole axis is at least two times the distance between the crest of the first external thread and the crest of the second external thread measured along an axis parallel and coplanar to the shaft axis.

Advantageously, such an extension of the surface guarantees that at least two crests of the first and second external threads of the threaded shaft always abut against the surface of the internal wall when the foot is rotated into the nut portion and when the foot reaches the desired position.

In a preferred embodiment, the first external thread, the second external thread and said one or more interposed external threads define an engagement portion to the nut portion along the threaded shaft.

According to a preferred embodiment, the threaded shaft comprises a plurality of engagement portions to said nut portion wherein said engagement portions are arranged one adjacent to the other, wherein each engagement portion is defined by said first external thread, said second external thread and said one or more interposed external threads.

Advantageously, the number of engagement portions along the threaded shaft may be opportunely chosen according to the distance that is foreseen between the supporting base and the surface on which the appliance stands.

Still advantageously, the number of engagement portions may also be opportunely chosen according to the entity of adjustment needed.

In a preferred embodiment, the external threads are completely circular.

In a further preferred embodiment, the external threads are not completely circular and preferably comprise flat portions. According to a preferred embodiment, the threaded shaft of the foot extends along a shaft axis and said flat portions are coplanar to a plan parallel, and not coinciding, to said shaft axis.

Advantageously, flat portions simplify manufacturing of the foot in particular when the foot is made by an injection moulding process. The use of a mould which is designed to create threads with flat portions, facilitates extraction of the foot from the mould after the injection process.

Preferably, the levelling foot comprises a head apt to abut the surface on which said appliance may stand on. Advantageously, the head increases the stability of the levelling foot.

In a preferred embodiment, the nut portion is integrally made with the supporting base, more preferably integrally made with an injection moulding process using a thermoplastic material. Advantageously, costs and/or production time are reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of preferred embodiments, provided with reference to the enclosed drawings. In particular:

- Figure 1 shows an isometric view of a household appliance according to a preferred embodiment of the invention with a side panel partially sectioned;

- Figure 2 shows an exploded view of some parts of the household appliance of Figure 1 isolated from the rest according to a preferred embodiment of the invention;

- Figure 3 shows an enlarged detail of Figure 2 isolated from the rest;

- Figure 4 shows another enlarged detail of Figure 2 isolated from the rest;

- Figure 5 shows the enlarged detail of Figure 4 from another point of view;

- Figure 6 shows a plan section view of Figure 3;

- Figure 6 A shows an enlarged detail of Figure 6;

- Figure 7 shows a plan section view of Figure 4;

- Figures 8 and 9 show operative configurations of the levelling system according to the invention;

- Figure 10 shows a further embodiment of Figure 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Aspects of the present invention will now be described more fully. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

As described below, the present invention has proved to be particularly advantageous when applied to a built-in dishwasher.

Nevertheless, the present invention may apply to any household appliance that needs to be levelled, such as a laundry washing or drying machine, a refrigeration appliance, a freezer appliance, a cooker, a microwave appliance, a coffee machine or the like.

With reference to Figure 1 a preferred embodiment of a household appliance 1 according to the invention is described. The household appliance 1 here represented is a built-in dishwasher 1, hereinafter also simply indicated as dishwasher 1, preferably embodied to be positioned within a furniture recess. In different embodiments the household appliance may be of a free-standing type.

The dishwasher 1 preferably comprises an outer box casing 4, preferably but not necessarily parallelepiped-shaped, and a treatment chamber (not visible in the Figure), for example having the shape of a hollow tub containing racks for receiving items to be washed, such as dishware, cutlery, and the like.

Access to the tub is achieved for example via a frontal opening formed on the tub. The opening is apt to be closed by a door assembly 8.

The outer casing 4 comprises a supporting base 10 arranged at the bottom part of the dishwasher 1 so that the underside 12 of the supporting base 10 faces the surface on which the dishwasher 1 stands on, for example the floor F.

The supporting base 10 advantageously supports the weight of the dishwasher 1. The supporting base 10 is preferably realized with a thermoplastic material, preferably made of polypropylene, and may be preferably produced by an injection moulding process. Advantageously, costs and/or production time are reduced.

The dishwasher 1 stands on, or is supported by, one or more feet 30 on the floor F, for example five feet 30, that are preferably arranged at the supporting base 10 and that protrude from the underside 12 thereof. Four feet 30 are preferably arranged at respective comers of the supporting base 10 and a further foot is preferably centrally arranged at a rear side of the supporting base 10. In further embodiments, numbers of feet and/or their positions on the supporting base may be different.

The dishwasher 1 is provided with a levelling system 50 that has the main aim of adjusting the height of the supporting base 10 and hence of the dishwasher 1, for example to reach alignment within the furniture recess for the bult-in dishwasher here illustrated or compensate for unevenness in the floor F.

According to an aspect of the invention, the levelling system 50 is preferably obtained by said feet 30 that are configured as height adjustable levelling feet 30. In the preferred embodiment illustrated and described herein, all the five feet 30 are height-adjustable feet according to the invention. In different embodiments, nevertheless, not all the feet may be height adjustable. Levelling operations require for acting on one or more of the levelling feet 30.

Hereinafter we will refer to one foot of the height-adjustable levelling feet, also simply indicated as foot 30, but it has to be understood that the following disclosure may apply to all the levelling feet 30 of the dishwasher 1.

The foot 30 preferably comprises a threaded shaft 32 having a plurality of external threads 34 and the supporting base 10 comprises a respective nut portion 14. The foot 30 is advantageously screw-coupled to the nut portion 14 via engagement of the threaded shaft 32 of the foot 30 and the nut portion 14 of the supporting base 10. The threaded shaft 32 of the foot 30 extends along a shaft axis Xs.

The height adjustment of the foot 30 is thus obtained by rotating the foot 30.

The foot 30 is preferably provided with a lower head 31 that abuts the floor F on which the dishwasher 1 stands on. Advantageously, the head 31 increases the stability of the foot 30.

Threads 34 are preferably embodied as ridges wrapped around the shaft axis Xs in the form of helixes. In a preferred embodiment, as visible in Figure 3, threads 34 show flat portions 34a and hence the threads 34 are not completely circular. Flat portions 34a are preferably co-planar to a plan parallel, and not coinciding, to the shaft axis Xs. Flat portions 34a simplify manufacturing of the foot 30 in particular when the foot 30 is made by an injection moulding process. The use of a mould which is designed to create threads 34 with flat portions 34a, facilitates extraction of the foot 30 from the mould after the injection process.

In different embodiments, not shown, flat portions may be omitted, and threads thus are completely circular.

The nut portion 14, as shown in Figure 7, comprises a hole 15 having an internal wall 16 comprising at least one internal thread 18 protruding therefrom. The internal wall 16 extends along a hole axis Xh. When the foot 30 is screw-coupled to the nut portion 14 the hole axis Xh and the shaft axis Xs coincide, or substantially coincide.

The nut portion 14 is preferably integrally made with the supporting base 10.

In the preferred embodiment illustrated and described herein, the internal wall 16 preferably comprises just one internal thread 18.

Preferably, the supporting base 10 with its nut portions 14 is easily obtained by an injection moulding process using a thermoplastic material.

Advantageously, by providing the internal wall 16 with just one internal thread 18 it is possible to simplify manufacturing of the supporting base 10 and/or reducing manufacturing time, in particular when the supporting base is made by an injection moulding process.

The internal wall 16 of the hole 15 is preferably cylindrically shaped. In different embodiments, nevertheless, the shape of the internal wall 16 may be slightly different form a cylinder, for example a portion of a cone (frustum).

According to an aspect of the invention, the plurality of external threads 34 of the threaded shaft 32 comprises a first external thread 36, a second external thread 38 and one or more interposed external threads 40 comprised between the first external thread 36 and the second external thread 38, as better shown in Figures 3, 6 and 6 A.

The first external thread 36, the second external thread 38 and the interposed external threads 40 are all configured to preferably engage with the internal thread 18 of the nut portion 14.

The crest 36a of the first external thread 36 shows a first radius Rl, the crest 38a of the second external thread 38 shows a second radius R2 and the crest 40a of each of the interposed external threads 40 shows a respective radius Ra.

According to an aspect of the invention, the first radius Rl of the first external thread 36 and the second radius R2 the second external thread 38 are greater than the radius Ra of the crest 40a of each of the interposed external threads 40.

The advantageous effect of said different radii will be explained later.

In the preferred embodiment illustrated and described with reference to Figures 1 to 9, there are two interposed external threads 40 between the first external thread 36 and the second external thread 38.

Preferably, the first radius Rl of the first external thread 36 is equal to the second radius R2 of the second external thread 38. Also, preferably, all the crests 40a of the interposed external threads 40 have the same radius Ra.

The first external thread 36, the second external thread 38 and the interposed external threads 40 define an engagement portion 42a along the threaded shaft 32. In a preferred embodiment, the threaded shaft 32 comprises only one engagement portion. In further preferred embodiments, the threaded shaft 32 preferably comprises two or more adjacent engagement portions, more preferably two or more identical adjacent engagement portions. In the preferred embodiment illustrated and described herein, for example, the threaded shaft 32 preferably comprises six identical adjacent engagement portions, indicated with reference numbers 42a-42f.

Preferably, the second external thread 38 of an engagement portion 42a-42e preferably coincides with the first external thread 36 of the adjacent engagement portion 42b-42f.

The foot 30 with one or more of its engagement portions 42a-42f interacts with the internal wall 16 of the nut portion 14 when the foot 30 is screw-coupled to the nut portion 14, as illustrated in Figures 8 and 9.

In particular, engagement portions 42a-42f interact with a surface 17 of the internal wall 16. Preferably said surface 17 is defined by the internal wall 16 of the nut portion 14, more preferably defined by the cylindrical portion of the internal wall 16.

When the foot 30 is screwed into the nut portion 14, through rotation of the foot 30, external threads 34 of the threaded shaft 32 engage one after the other with the internal thread 18 of the nut portion 14.

The foot 30 is rotated until the desired position of the supporting base 10 with respect to the floor F is reached. Figures 8 and 9 show two of said possible desired positions.

According to an advantageous aspect of the invention, in the engaging position the crest 36a of the first external thread 36 and the crest 38a of the second external thread 38 abut against the surface 17 of the internal wall 16 of the nut portion 14 while the crests 40a of the interposed external threads 40 do not abut against said surface 17.

Interference of the crests 36a, 38a of the first and second external threads 36, 38 against said surface 17 generates an interference force that limits any unwanted movement of the foot 30 with respect to the nut portion 14.

Advantageously, the adjustment position obtained through the levelling system 50 is therefore reached in a reliable maimer. Furthermore, the height feet positions obtained through the levelling system 50 are kept in a simple manner, in particular even when the dishwasher 1 is subjected to vibrations during functioning, for example during rotation of spray arms or activation of a draining/circulating pump. Still advantageously, in case the first radius R1 of the first external thread 36 is equal to the second radius R2 of the second external thread 38 the screwing force when the foot 30 is rotated, i.e. screwed into the nut portion 14, is constant or substantially constant.

Still advantageously, in case the internal wall 16 of the hole 15 is cylindrically shaped, the friction between the first external thread 36 and the second external thread 38 is kept constant when the foot 30 is rotated, i.e. screwed/unscrewed into/from the nut portion 14.

In a preferred embodiment in order to guarantee interference of both the crests 36a, 38a of the first and second external threads 36, 38 against said surface 17, the extension of the surface 17 is at least equal to the distance between the crests 36a, 38a of the first and second external threads 36, 38.

In other words, preferably:

Ds > De wherein:

De is the distance defined between the crest 36a of the first external thread 36 and the crest 38a of the second external thread 38 measured along an axis XI parallel and coplanar to the shaft axis Xs, as illustrated in Figure 6A;

Ds is the extension of the surface 17 of the internal wall 16 measured along an axis X2 parallel and coplanar to the hole axis Xh, as illustrated in Figure 7.

More preferably, as in the embodiment illustrated and described herein, the extension of the surface 17 is at least two times the distance between the crests 36a, 38a of the first and second external threads 36, 38. This extension of the surface 17 guarantees that at least two crests 36a, 38a of the first and second external threads 36, 38 of the threaded shaft 32 always abut against the surface 17 when the foot 30 is rotated into the nut portion 14 and when the foot 30 reaches the desired position (as illustrated in Figures 8 and 9).

In other words, more preferably:

Ds > 2*Dc.

In the embodiment illustrated and described above, the levelling foot comprises six identical engagement portions wherein each engagement portion comprises a first external thread, a second external thread and two interposed external threads. In different embodiments, nevertheless, the number of engagement portions and/or the number of the interposed external threads may vary according to various parameter, such as the pitch of the threads of the threaded shaft and/or the extension of the nut portion.

For example, the number of engagement portions along the threaded shaft may be opportunely chosen according to the distance that is foreseen between the supporting base and the floor on which the dishwasher stands. The number of engagement portions may also be opportunely chosen according to the entity of adjustment needed.

Figure 10 represents a foot 130 according to a further embodiment of the invention. In the drawings, corresponding characteristics and/or components of the embodiment previously described are identified by the same reference numbers.

According to this preferred embodiment, the threaded shaft 32 preferably comprises five adjacent engagement portions 142a- 142e, wherein the five adjacent engagement portions 142a-142e are not identical but have a different number of interposed external threads. In particular: the first engagement portion 142a comprises a first external thread 36, a second external thread 38 and one interposed external thread 40; the second engagement portion 142b comprises a first external thread 36, a second external thread 38 and two interposed external threads 40; the third engagement portion 142c comprises a first external thread 36, a second external thread 38 and three interposed external threads 40; the fourth engagement portion 142d comprises a first external thread 36, a second external thread 38 and two interposed external threads 40; the fifth engagement portion 142e comprises a first external thread 36, a second external thread 38 and two interposed external threads 40.

It has to be noted that according to this embodiment, each engagement portion 142a-142e has a respective distance Dca-Dce between the crests 36a, 38a of the first and second external threads 36, 38.

In a preferred embodiment in order to guarantee interference of both the crests 36a, 38a of the first and second external threads 36, 38 against said surface 17 of any engagement portion 142a- 142e, the extension of the surface 17 is at least equal to the maximum distance between the crests 36a, 38a of the first and second external threads 36, 38.

In other words, preferably:

Ds > max (Dca-Dce) wherein:

Dca-Dce is the distance defined between the crest 36a of the first external thread 36 and the crest 38a of the second external thread 38 in a respective engagement portion 142a- 142e measured along an axis XI parallel and coplanar to the shaft axis Xs, as illustrated in Figure 10;

D s is the extension of the surface 17 of the internal wall 16 measured along an axis X2 parallel and coplanar to the hole axis Xh, as illustrated in Figure 7.

More preferably, the extension of the surface 17 is at least two times the maximum distance between the crests 36a, 38a of the first and second external threads 36, 38. This extension of the surface 17 guarantees that at least two crests 36a, 38a of the first and second external threads 36, 38 of any engagement portion 142a- 142e of the threaded shaft 32 always abut against the surface 17 when the foot 30 is rotated into the nut portion 14 and when the foot 30 reaches the desired position. In other words, more preferably:

Ds > 2*max (Dca-Dce)

It has thus been shown that the present invention allows the set objects to be achieved. In particular, the invention makes possible to provide a household appliance with a levelling system that improves the height adjustment action of the appliance.

While the present invention has been described with reference to particular embodiments shown in the figures, it should be noted that the present invention is not limited to the specific embodiments illustrated and described herein; on the contrary, further variants of the embodiments described herein fall within the scope of the present invention, which is defined in the appended claims.

Claims

1. A household appliance (1) comprising an outer casing (4) having a supporting base (10) and a levelling system (50), said levelling system (50) comprising at least one height-adjustable levelling foot (30; 130) arranged on said supporting base (10) and protruding from an underside (12) of said supporting base (10), said foot (30; 130) comprising a threaded shaft (32) having a plurality of external threads (34) and said supporting base (10) comprising a nut portion (14) comprising a hole (15) having an internal wall (16) comprising at least one internal thread (18) protruding therefrom, said foot (30; 130) being screw-coupled to said nut portion (14) via engagement of said threaded shaft (32) of said foot (30; 130) and said nut portion (14) of said supporting base (10); characterized in that said plurality of external threads (34) of said threaded shaft (32) comprises a first external thread (36), a second external thread (38) and one or more interposed external threads (40) comprised between said first external thread (36) and said second external thread (38), wherein the crest (36a) of said first external thread (36) has a first radius (Rl), the crest (38a) of said second external thread (38) has a second radius (R2) and wherein said first radius (Rl) and said second radius (R2) are greater than the radius (Ra) of the crest (40a) of each of said interposed external threads (40).

2. A household appliance (1) according to claim 1, characterized in that said first radius (Rl) of said first external thread (36) is equal to said second radius (R2) of said second external thread (38).

3. A household appliance (1) according to claim 1 or 2, characterized in that all the crests (40a) of said interposed external threads (40) have the same radius (Ra).

4. A household appliance (1) according to any of the preceding claims, characterized in that said internal wall (16) of said hole (15) of said nut portion (14) is a cylindrical inner wall.

5. A household appliance (1) according to any of the preceding claims, characterized in that said internal wall (16) of said hole (15) of said nut portion (14) comprises just one internal thread (18) protruding therefrom.

6. A household appliance (1) according to any of the preceding claims, characterized in that said threaded shaft (32) of said foot (30; 130) extends along a shaft axis (Xs) and said internal wall (16) of said hole (15) extends along a hole axis (Xh), wherein said shaft axis (Xs) and said hole axis (Xh) coincide when said foot (30; 130) is screw-coupled to said nut portion (14), wherein the extension (Ds) of a surface (17) of said internal wall (16) measured along an axis (X2) parallel and coplanar to said hole axis (Xh) is at least equal to the distance (De, Dca-Dce) between the crest (36a) of said first external thread (36) and the crest (38a) of said second external thread (38) measured along an axis (XI) parallel and coplanar to said shaft axis (Xs).

7. A household appliance (1) according to claim 6, characterized in that the extension (Ds) of said surface (17) of said internal wall (16) measured along an axis (Xh) parallel and coplanar to said hole axis (Xh) is at least two times said distance (De, Dca-Dce) between the crest (36a) of said first external thread (36) and the crest (38a) of said second external thread (38) measured along an axis (XI) parallel and coplanar to said shaft axis (Xs).

8. A household appliance (1) according to any of the preceding claims, characterized in that said first external thread (36), said second external thread (38) and said one or more interposed external threads (40) define an engagement portion (42a-42f; 142a-142e) to said nut portion (14) along said threaded shaft (32).

9. A household appliance (1) according to any of the preceding claims, characterized in that said threaded shaft (32) comprises a plurality of engagement portions (42a-42f; 142a- 142e) to said nut portion (14) wherein said engagement portions (42a-42f; 142a- 142e) are arranged one adjacent to the other, wherein each engagement portion (42a-42f; 142a- 142e) is defined by said first external thread (36), said second external thread (38) and said one or more interposed external threads (40).

10. A household appliance (1) according to any of the preceding claims, characterized in that said external threads (34) are completely circular.

11. A household appliance (1) according to any of the claims 1 to 9, characterized in that said external threads (34) comprise flat portions (34a).

12. A household appliance (1) according to claim 11, characterized in that said threaded shaft (32) of said foot (30; 130) extends along a shaft axis (Xs) and said flat portions (34a) are co-planar to a plan parallel, and not coinciding, to said shaft axis (Xs).

13. A household appliance (1) according to any of the preceding claims, characterized in that said levelling foot (30; 130) comprises a head (31) apt to abut the surface (F) on which said appliance (1) may stand on.

14. A household appliance (1) according to any of the preceding claims, characterized in that said nut portion (14) is integrally made with said supporting base (10).