EP2214533B1 - Household appliance having a height-adjusting device for an appliance pedestal - Google Patents

Abstract

A household appliance, particularly a dishwasher or washing machine, having a height-adjusting device for an appliance pedestal. The height-adjusting device may include at least one drive gear engaged with a transmission drive converting the rotary motion of the drive gear into a lift motion of the appliance pedestal. In an exemplary embodiment of the invention, the drive gear includes a torque-limiting element operable to enable a deflecting motion of the drive gear from an operating position when a limit torque is exceeded, and which releases the engagement between the drive gear and the transmission drive.

Description

The invention relates to a household appliance with a height adjustment device for a device according to the preamble of patent claim 1.

Built-in kitchen appliances can be used in the installed state by means of height-adjustable device feet in the correct installation position. This was a height adjustment of the inaccessible rear feet by means of a device front side operable adjusting rod.

From the WO 2004/107914 A1 a generic height adjustment device for a device base of a household appliance is known in which a drive gear with a transmission gear is in meshing, which transmits the rotational movement of the drive gear in a lifting movement of the device base.

Is concrete in the WO 2004/107914 A1 the drive gear a drive worm, which sits non-rotatably on an adjusting rod and is mounted stationary and rotatable in a device-rear bearing housing. The drive worm meshes with a worm wheel that is threadedly engaged with a device foot threaded shaft. The threaded shaft has an end stop. This secures the gearbox against overload and prevents excessive lifting movement. For this purpose, the end stop is designed so that the worm wheel springs back on reaching the end stop by a thread pitch of the threaded shaft. The formation of the end stop on the threaded shank is complex in terms of components and manufacturing technology.

The object of the invention is to provide a household appliance with a height adjustment, which is secured in a simple manner against overloading.

The object is solved by the features of claim 1. Advantageous developments emerge from the subclaims.

The invention relates to a household appliance, in particular dishwashing machine or washing machine, with a height adjustment device for a device, which has at least one drive gear, with a rotational movement of the drive gear in a stroke movement of the device base transmitting transmission gear is in meshing engagement. , characterized in that.

According to the characterizing clause of claim 1, the drive gear is associated with a torque limiting element permitting deflection movement of the drive gear from its operating position which releases the meshing engagement between the drive gear and the transmission gear, thereby effecting tooth engagement between the drive gear and a transmission gear at least in the short term The evasive movement allows the drive gear to skip at least one pitch with respect to the transmission gear member, thereby relieving the teeth of the drive gear and the transmission gear member.

The evasive movement of the drive gear can thus take place when an allowable maximum torque is exceeded. The permissible maximum torque is to be determined depending on the structural design of the torque limiting element and as a function of its material strength. The permissible maximum torque is designed so that the drive gear, the transmission gear and / or a drive gear driving shaft or adjusting rod are not damaged. With the torque limiting element according to the invention, as in a friction clutch, when the maximum torque is exceeded, the drive gear is briefly brought out of mesh, so that it rotates empty and no torque is passed to the transmission gear. If the introduced torque falls below the limit torque, then the drive gear again comes into meshing engagement with the transmission gear.

With the torque limiting element according to the invention a reliable torque limitation is not only when the device base shaft of the height adjustment is moved against an end stop, as is the case in the prior art. Rather, it is ensured according to the invention that a torque limitation takes place over the entire adjustment range of the device foot shaft.

The height adjustment device according to the invention can be used in particular for rear-mounted equipment feet in built-in appliances. With the height adjustment of the inaccessible rear area of the built-in appliance can be raised until the household appliance reaches a positionally correct height position. In particular, when using plastic components for the height adjustment device here in the prior art, the risk that torques are initiated by a manual operation of the height adjustment, which can lead to destruction of the plastic component.

As already mentioned, the height adjustment device according to the invention can be used in particular for rear feet of built-in appliances. In this case, a height adjustment with a provided on the front side of the household appliance actuator. The actuator is seated on an adjustment rod which extends to the rear height adjustment device. The rear end of the adjusting rod may carry the driving gear, for example a worm, which in turn meshes with a worm gear of the transmission gear. The driven gear or worm wheel is fixedly mounted in a bearing housing and has an internal thread which is in engagement with an external thread of the device foot shaft. Upon rotation of the output gear thus takes place a lifting movement of the device base. The threaded shaft is arranged in a bearing bush of the bearing housing. In order to avoid a rotational movement of the device foot shaft, this may have at least one outer flat which is positively in engagement with the bearing bush.

According to the invention the drive gear is designed so that when a torque transmission to the transmission gear between the drive gear and the output gear of the transmission gear, a deflection force is generated, with which the drive gear is pressed against the torque limiting element. In this case, the limiting element may be formed elastically deflectable. The aforementioned deflection force is generated by correspondingly angled teeth of the drive gear and / or the output gear, in particular by a drive worm and a worm wheel as the output element.

During a torque transmission, therefore, the drive gear presses with a deflection force against the torque limiting element. With too much deflection force gives the torque limiting element elastically, whereby the deflection movement of the drive gear takes place. In this way, the drive gear skips the teeth of the driven gear, whereupon the elastically recessed torque limiting element again shifts the drive gear into meshing engagement with the driven gear. This skipping of the teeth is perceived as a rattle noise, so that the user receives feedback that the household appliance abuts against a stop, such as an upper kitchen worktop.

In terms of component reduction, it is preferred if the torque limiting element is at the same time a housing part of a transmission housing in which the drive gear is rotatably mounted. The limiting element is thus integrated in the housing, which therefore assumes both the storage and the torque limitation of the drive gear in a dual function.

The torque limiting element can be brought either directly into contact with the drive gear, or alternatively in abutment with a drive gear driving shaft can be brought into abutment. For a compact design of the height adjustment device, it is preferred if the torque limiting element can be brought directly into contact with the toothed wheel outer contour of the drive gear.

As already mentioned above, the torque transmission preferably takes place with a worm drive gear meshing with a worm gear of the transmission gear. In this case, the axis of rotation of the drive worm can run perpendicular to the axis of rotation of the worm wheel.

Manufacturing technology is simple if the torque limiting element is made of the same material and / or in one piece with a mounting base of the household appliance. The mounting base serves to support unit units. It may be manufactured together with the torque limiting element as a plastic injection molded part. The compensating movement of the drive worm can in this case take place in a transverse direction to the axis of rotation of the worm wheel.

For a reliable torque limitation, a corresponding motion guide of the drive screw in the direction of the torque limiting element required. For this purpose, the drive worm be associated with a height stop, with which the deflection movement of the drive worm is guided in the event of overload in the direction of the torque limiting element. To form such a height stop, the drive screw can be extended with a bearing journal, which is guided in a bearing opening in the manner of a slotted guide. The bearing opening may in particular be a slot extending in the direction of the torque limiting element. The provided by the slot displacement for the drive screw is dimensioned such that the drive screw can reach with correspondingly large deflection force out of mesh with the worm wheel.

In a rest position, that is, in the non-actuated state, the height adjustment device, the torque limiting element may be approximately in contact with the outer contour of the drive screw. In this way, a play-free storage of the drive screw is guaranteed.

The torque limiting element may preferably be a spring rib. Such a spring rib has a projecting free end, which can be made easily elastically deflectable manufacturing technology with little effort.

Hereinafter, an embodiment of the invention with reference to the accompanying figures is shown.

• Fig. 1 in einer perspektivischen Ansicht einen Montageboden eines Haushaltsgerätes;
• Fig. 2 in einer vergrößerten Schnittansicht von oben ein frontseitiges Betätigungsglied der Höhenverstellvorrichtung entlang der Schnittebene I-I;
• Fig. 3 eine vergrößerte Teilschnittansicht entlang der Schnittebene II-II aus der Fig. 1; und
• Fig. 4 in einer perspektivischen Detailansicht die Höhenverstellvorrichtung.

Show it:

• Fig. 1 in a perspective view of a mounting floor of a household appliance;
• Fig. 2 in an enlarged sectional view from above a front-side actuator of the height adjustment along the cutting plane II;
• Fig. 3 an enlarged partial sectional view along the section plane II-II of the Fig. 1 ; and
• Fig. 4 in a perspective detail view of the height adjustment device.

In the Fig. 1 is a manufactured as a plastic injection molded assembly floor 1 of a household appliance 3 only indicated. The device units provided in the household appliance 3 have been omitted for reasons of clarity. The mounting base 1 has front side two lateral, projecting forward support arms 5 with front feet 7 on. In addition, a height-adjustable device base 9 is provided in the rear region of the mounting base 1 approximately in the middle, as in the Fig. 3 is shown. In the Fig. 1 on the other hand, only the height adjustment device 11 of the middle foot 9 is visible. The height adjustment device 11 will be described later.

Like from the Fig. 1 is further apparent, the height adjustment device 11 is associated with an adjusting rod 13 which extends as a drive shaft to the front side 15 of the mounting base 1. The front end of the adjusting rod 13 has according to the Fig. 2 an adjusting bushing 17, which is rotatably mounted in a bearing opening 19 of the here double-walled mounting base front side 15. The adjusting bush 17 of the adjusting rod 13 is provided at the front with a tool attachment 21, with which the adjusting rod 13 can be rotationally actuated.

The adjusting rod 13 is at its rear end drivingly connected to the height adjustment device 11 in connection. For this purpose sits on the rear end of the control rod 13 rotatably as a drive gear drive screw 23, which is in meshing engagement with a transmission gear 25 of the height adjustment device 11. The transmission gear 25 transmits a rotational movement of the drive screw 23 in a linear lifting movement of the device base 9. According to the Fig. 3 has the transmission gear 25 a integrally formed on the mounting base 1 gear housing 27. The transmission housing 27 is subdivided into a worm housing 29 and into a substantially hollow-cylindrical shaft housing 31. In the shaft housing 31, a threaded shaft 33 of the device base 9 is height-adjustable and rotatably arranged. For the rotationally fixed arrangement, the threaded shaft 33 has a in the Fig. 4 shown flattening 35 in the external thread of the threaded shaft 33. Corresponding to this flat 35 and the shaft channel 37 of the shaft housing 31 is flattened so that the threaded shaft 33 can move only in the vertical direction, but not in one direction.

Like from the Fig. 4 shows, the drive screw 23 is extended with a bearing pin 39 which rotates in a slot 41 in the rear wall 43 of the mounting base is stored. Between the drive screw 23 and the threaded shank 33 of the device base 9, a worm wheel 45 is connected. The external gears 46 of the worm wheel 45 mesh with the helical worm helix 47 of the drive worm 23. In addition, the worm wheel 45 is provided on the inside with an internal thread 48 which is in engagement with the external thread of the threaded shaft 33. According to the Fig. 3 the shaft channel 37 is bisected in the vertical direction. Between the two channel sections, the worm wheel 45 is arranged and in screw connection with the threaded shank 33.

The axis of rotation 49 of the drive worm 23 extends horizontally in the depth direction according to the figures, while the axis of rotation 51 of the threaded shaft 33 extends perpendicular thereto.

The worm housing 29 is bounded laterally by a torque limiting element 53. The torque limiting element 53 here is a spring rib, which is integrally formed on the mounting base 1 and whose upper end is freely movable. The drive screw 23 is arranged in the non-actuated state of the height adjustment device 11 and in an operating position substantially free of play between the spring rib 47 of the screw housing part 29 and the worm wheel 45.

In the Fig. 3 and 4 the normal operating position of the height adjustment device 11 is shown. Consequently, the drive worm 23 meshes with the worm wheel 45. In a rotary actuation of the control rod 13, the worm wheel 45 is thus rotated via the drive worm 23, whereby a lifting movement of the device foot 9 in the vertical direction takes place.

By means of the spring rib 53 there is a torque limitation, provided that acting on the height adjustment device 11 torque exceeds a limit torque. Such an abnormal case of normal operation case arises when the rear of the device area abuts by height adjustment of the rear foot 9 as against a kitchen worktop, so that no further lifting movement of the built-in device is more possible. When the limit torque is exceeded, a deflection force F _A is created between the helically running worm helix 47 and the external gears 46 of the worm wheel 45, with which the drive worm 23 moves in Transverse direction against the spring rib 53 presses. In case of overload, the spring rib 53 yields elastically, so that the drive worm 23 performs an evasive movement in the direction of arrow I from its operating position, ie, that the worm helix 47 jumps over the outer teeth 46 of the worm wheel 45 by one pitch. This skipping is perceived as a rattle noise, so that a corresponding lifting operation of the rear, middle device foot 9 can be stopped.

Like from the Fig. 4 As can be seen, the compensating movement I of the drive worm 23 takes place in a transverse direction to the axis of rotation 51 of the worm wheel 45. Likewise, the oblong hole 41, in which the bearing journal 39 of the drive worm 23 is mounted, extends in the transverse direction. The upper and lower longitudinal edges 55 of the elongated hole 41 serve as a height stop, with which the deflection movement I of the drive worm 23 is reliably guided in the direction of the spring rib 53.

LIST OF REFERENCE NUMBERS

1

assembly floor

3

household appliance

5

Beam

7

front device foot

9

rear device foot

11

height adjustment

13

control rod

15

Front of the mounting floor 1

17

adjusting bush

19

bearing opening

21

tool attachment

23

Drive gear, drive worm

25

transmission gear

27

gearbox

29

snail shell

31

shaft housing

33

threaded shaft

35

flattening

37

shaft channel

39

pivot

41

Long hole

43

Rear wall of the mounting floor

45

Output gear, worm wheel

46

External gears of the worm wheel

47

screw spiral

48

Internal thread of the worm wheel

49, 51

rotational axes

53

Torque-limiting element

55

height stop

Claims (13)

1. Domestic appliance, particularly dishwasher or washing machine, with a height adjusting device (11) for an appliance foot (9), which comprises at least one drive gearwheel (23), which is disposed in mesh with a translating transmission (25) translating the rotational movement of the drive gearwheel (23) into a lifting movement of the appliance foot (9), characterised in that associated with the drive gearwheel (23) is a torque limiting element (53) which if a limiting torque is exceeded enables a deviating movement (I) of the drive gearwheel (23) out of its operating position and which frees the tooth engagement between the drive gearwheel (23) and the translating transmission (25).
2. Domestic appliance according to claim 1, characterised in that the drive gearwheel (23) presses against the torque limiting element (53) by a deflecting force (F_A) arising when the transmission of torque takes place.
3. Domestic appliance according to claim 1 or 2, characterised in that the torque limiting element (53) is resiliently deflectable.
4. Domestic appliance according to claim 1, 2 or 3, characterised in that the torque limiting element (53) is a housing part of a housing (29) in which the drive gearwheel (23) is rotatably mounted.
5. Domestic appliance according to any one of the preceding claims, characterised in that the torque limiting element (53) can be brought into contact with the gearwheel outer profile of the drive gearwheel (23).
6. Domestic appliance according to any one of the preceding claims, characterised in that the drive gearwheel (23) is a worm which meshes with a worm wheel and, in particular, the axis (49) of rotation of the work lies perpendicularly to the axis (51) of rotation of the worm wheel (45).
7. Domestic appliance according to any one of the preceding claims, characterised in that the torque limiting element (53) is unitary in terms of material and/or integral with a mounting base (1) of the domestic appliance.
8. Domestic appliance according to claim 7, characterised in that the mounting base (1) together with the torque limiting element (53) is a plastics material injection-moulded part.
9. Domestic appliance according to any one of the preceding claims, characterised in that the drive gearwheel (23) is arranged to be fixed in terms of rotation on an adjusting rod (13).
10. Domestic appliance according to any one of claims 6 to 9, characterised in that the compensating movement (I) of the drive gearwheel (23) is oriented transversely to the axis (51) of rotation of the worm wheel (45).
11. Domestic appliance according to any one of claims 6 to 10, characterised in that associated with the drive gearwheel (23) constructed as a worm is a height abutment (55) by which the deviating movement (I) thereof is guided in the direction of the torque limiting element (53).
12. Domestic appliance according to claim 11, characterised in that for formation of the height abutment (55) the worm is prolonged by a bearing pin (39) guided in a bearing opening, particularly a slot (41).
13. Domestic appliance according to any one of the preceding claims, characterised in that the torque limiting element (53) is a spring rib.

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