The invention relates to a mounting star for stabilizing the rear wall of a drum-type component of a washing machine, and for assembly on it, at least three arms of which component are embodied in the center of the mounting star and include hollow molded bodies with a box-like, open profile, and with support points provided at a distance of a length from the central axis of the mounting star, preferably to approximately the mid-length of each arm, which points serve as a support against the rear wall of the drum-type component.
Such mounting stars for a washing drum are disclosed in DE 14 60 840 A1 and DE 24 32 465 A1. Mounting stars with even greater stiffness are required for tubs for transmitting greater forces than are required for a washing drum. They are comprised mainly of cast steel, as disclosed in DE 39 27 166 A1 for example, but are becoming dispensable because tubs are increasingly being produced from plastic and the stiffness is therefore becoming a design element of the tub.
In the mounting stars of prior art their high price is the main criticism, this price resulting from their design as individual molded components and from the relatively high quantity of material required for them. Moreover, the mounting stars of prior art are relatively heavy and therefore require a correspondingly heavy balancing weight on the front side of the tubs concerned, which in turn generates higher costs than necessary.
The object if the invention is therefore to design a mounting star of the type already described so that it is capable of saving weight and costs, with the lowest possible material consumption, for transmitting the forces acting in washing machines in the region of tubs or washing drums.
This object is achieved according to the invention in such a manner that the open profile of the arms comprises a pair of surfaces which are not connected together and are at least similar to a flat rectangle, which surfaces form the cross-section of supports and are orientated, with one of their short sides, towards the rear wall of the drum-type component, and that the two supports are each connected, at least at the support points, by a third support with a similar cross-sectional surface from arm to arm, to a support of the other arms. This lattice structure provides the best conditions for designing the mounting star with the lowest possible material consumption, yet so that it is so stable that its weight can be reduced by almost 40% compared to a conventional mounting star, but with the same force transmitting capacity. This also results in considerable cost savings as far as the other components of the washing machine are concerned.
These savings may prove extremely effective if, in a further development of the invention, the supports arranged in pairs are connected together by means of a latticework. The supports required for the transmission of forces on the drum-type component may then be dimensioned exclusively to achieve this object, whilst their dimensional stability in and relative to each other is achieved by the latticework, which can be designed in a filigree fashion.
One design has proved to be a particularly well suited further development in which at least the supports arranged in pairs run in an arc shape with bents opposing each other. This already provides the structure with sufficient stiffness to render further measures superfluous.
The above further development is advantageously rendered particularly stable when the neutral fibers of both supports of a pair run through the central axis of the mounting star and each of the supports running through the central axis forms part of two arms so that the respectively assigned supports of each arm intersect in the central axis.
According to an advantageous further development of the invention the connection of the adjacent supports of two arms at the support points to a further support, which runs outside the central axis, is then sufficient.
In one variant the arc-shaped supports continue running from the support points with the same curvature in the direction of the arm ends and are connected to each other at the end points of the arms to produce a stable shape of the mounting star arms.
In another variant, in which the arms of the mounting arm are intrinsically even more torsionally stiff, the arc-shaped supports continue running from the supports with a greater curvature and intersect to connect to each other before the ends of the arms. Here a particularly torsionally stiff effect is achieved if the arc-shaped supports terminate at the ends of the arms at certain distance from each other and are connected to each other by means of a cross bracket.
In a further variant the supports of each pair are connected to each other level with the support points by a cross strut. Although the cross strut may be designed in highly filigree fashion, it provides torsional stiffness in the main supports of the arms.
For stabilizing the rear wall of a drum, all the arms are advantageously fastened to a bearing hub so that each arc running through the central axis of the mounting star is arranged at a certain distance from the adjacent arc of the adjacent arm. Because of the shaping of the supports, this automatically provides a basic shape for a lattice work that guarantees the dimensional stability of the mounting star.
Correspondingly, the supports of all the arms are connected to each other, separated by the same fastening distance, with a round for the bearing axis of the washing drum, for stabilizing the rear wall of a washing drum.
A mounting star designed according to the invention has a profile that is open towards the sides so that all its components are manufactured from a material in the continuous casting process according to a further advantageous embodiment. This method provides the most favorable conditions for low cost mass production of the mounting star.
In order to avoid water or air turbulence in the tub at the profile openings of a mounting star fitted to the washing drum according to the invention, which could have a braking influence on the rotation of the washing drum and could even generate noises, it is proposed, in a variant of a further development of the invention, to seal cavities formed by the latticework of the arms on the side facing away from the drum-type component, at least partially by a cover not participating in the flow of force from the arms, or at least partially by a sealing compound not participating in the flow of force from the arms.
The invention is explained in the following with reference to an exemplary example represented in the drawing, in which
Washing drum 4 is also supported by a mounting star 13 on its rear side, but its center is connected fixedly in terms of rotation to shaft journal 5 so that washing drum 4 can be rotated inside tub 3 concentrically to bearing 12 of the tub.
A three-armed mounting star 13 of prior art is represented in
It has now been found that the forces for the rotary transmission and for balancing gravitational and centrifugal forces on drum 4 are applied essentially by supports 16 to 20, whilst cords 21 to 24 mainly serve the purpose of keeping the supports apart at all points and stiffening them. At individual points 26 and 36 to 41 they also serve for fastening and support against the rear wall of washing drum 4 and there of course for introducing the forces. This introduction of forces, however, could also be undertaken without problem by supports 16 and 20 alone. Unlike in the example of mounting star 13 of prior art shown, mounting stars are also known (not shown) which, for each arm, only have two parallel supports, but here these arms have a larger cross-sectional area than in the case of the mounting star of prior art shown, and are connected to each other by a lower cord and support, for each support, a flange-like upper cord on the side facing away from the rear wall, which upper cord serves on the one hand to stiffen the supports and on the other to fasten the rear wall.
In the knowledge of these conditions on the mounting stars of prior art, and in an endeavor to ensure sparing use of materials, the invention relies upon new shapes for a mounting star for which exemplary embodiments are represented in
The mounting star in
According to
The arc-shaped supports 27 to 29 and 42 to 44 have proved the best for transmitting and transferring the forces generated. If other requirements necessitate this, however, the supports may also have smaller curvatures, or may even be constructed at least approximately straight. However, further support parts in a lattice-type arrangement are required, which means that the weight advantage that can be achieved with the exemplary embodiments represented and optimized is partially lost again. However, there is still a significant advantage over the mounting stars of prior art already represented.
To ensure that the open lattice structures do not lead to water or air turbulence during washing (foaming) or of air (braking of the drum during spinning) when a mounting star according to the invention is used on a washing drum, the openings of the structures can be sealed by a method not shown in further detail, completely or partially on the side facing away from the rear wall of the washing drum by a cover or filling not participating in the flow of forces from the arms. For example, a covering may be provided by a molded skin of the same material as the supports, or by another material which is connected to the supports by other means, e.g. by gluing. For example, filling may be achieved by foaming the cavities.
Number | Date | Country | Kind |
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10 2004 047 996.8 | Oct 2004 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP05/54954 | 9/30/2005 | WO | 00 | 3/29/2007 |