Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F37/00—Details specific to washing machines covered by groups D06F21/00 - D06F25/00
  • D06F37/20—Mountings, e.g. resilient mountings, for the rotary receptacle, motor, tub or casing; Preventing or damping vibrations
  • D06F37/22—Mountings, e.g. resilient mountings, for the rotary receptacle, motor, tub or casing; Preventing or damping vibrations in machines with a receptacle rotating or oscillating about a horizontal axis
  • D06F37/225—Damping vibrations by displacing, supplying or ejecting a material, e.g. liquid, into or from counterbalancing pockets

Definitions

• the present invention refers to clothes washing machine, in particular of the household type, provided with an improved arrangement for dynamically balancing its rotating drum.
• washing machine of the front-loading type refers specially to a washing machine of the front-loading type, and for greater convenience of exemplification the following description is actually referred to such a type of washing machine, it can in an advantageous manner be applied also to other types of washing machines, in particular to the ones that are loaded from the top or even to the machines that have their drum rotating about a vertical axis.
• a substantially unstable situation therefore occurs, in which the machine gets unbalanced and then automatically re-balances itself in a practically continuous manner. This leads to a particularly disturbing condition, since, while vibrations fail to be suppressed to any definitive manner, the machine keeps generating a remarkable noise periodically.
• - Figure 1 is a cross-sectional view showing schematically an annular hollow body according to the present invention
• - Figures 2a and 2b are views of two distinct shapes of the perimeter of the hollow bodies according to the present invention
• - Figure 3 is a view illustrating the operation conditions of an embodiment of the present invention
• FIG. 4 is a view illustrating a particular operation condition
• FIG. 5 is a view of an improved embodiment of the present invention.
• FIGS. 6, 7 and 7a are views illustrating various possibilities of application of a plurality of hollow bodies according to the present invention.
• FIG. 8 is a view of different shapes of the movable balancing weights in said hollow bodies
• FIG. 9 is a view of an improved shape of the hollow bodies provided with prominent lobes according to the present invention.
• FIGS. 10 and 10a are views illustrating a particular case with reference to the shape and the arrangement of the hollow bodies
• FIG. 11 is a view showing an improved embodiment as an alternative to the embodiment shown in Figure 10.
• Each hollow body shall feature a plurality of "lobes", ie. portions of perimeter being evenly distributed along said perimeter and situated outside the circle inscribed within said perimeter.
• said lobes are arranged so as to be regularly distributed along a single circumference that has its center coinciding with the center of gravity of the respective hollow body, even if the perimeter of said hollow body does not of course coincide with said circumference, and that said center of gravity of the hollow body is situated on the axis of rotation and symmetry of the drum.
• Figure 1 illustrates a preferred embodiment of such a hollow body, which is provided with three lobes arranged at regular intervals along the perimeter.
• the perimeter of the hollow body is formed by three curvilinear sections 3, which are represented in the Figure as three arcs of three respective circumferences having a radius R which is greater than the radius r of the circumference 2.
• the distance (r-f) between the point 4 and the point 5 represents the difference in height which a movable weight being positioned on a lobe should overcome to reach said point 5 by opposing the centrifugal force generated by the rotation of the drum.
• the balancing weight In order to reach intermediate points 6 situated along said perimeter, the balancing weight has to overcome a smaller, but in any case positive difference in height (r-f).
• said three arcs may now be assumed to be identical, so that also their respective radii and angles of curvature will be the same. If the radii a and a' are now drawn between the center OA and both ends of the corresponding arc A, and if the same thing is done as far as the radii b and b', as well as the radii c and c' are concerned, it can be noticed that said six radii will intersect each other, while the intersection points, along with the afore cited centers OA, OB and 0C, will define the vertices of a hexagon H which is shown with dotted lines in the Figure.
• Each inner point in said hexagon is more distant from a generic point P situated within any of said three arcs A, B and C than the radii of equal length a, a', b, b' , c and c', for any position of said generic point P except for the extreme points of the three lobes 1.
• a first improvement which is rather an optimization, relates to the possibility of providing hollow bodies provided with a more or less large number of lobes, wherein the sections between contiguous lobes are more or less curved or straight.
• This allows for a wide range of options that may be appropriately selected in view of optimizing, on the one hand, the minimum rotational speed at which the movable balancing weight are supposed to intervene and, on the other hand, their actual capacity of balancing the unbalanced drum ( Figures 2a, 2b) .
• a second improvement consists in the possibility of introducing a considerable plurality of movable balancing weights, such as for instance metal balls, in said hollow body. This is effective in increasing the balancing mass, and hence the balancing capacity even in front of markedly unbalanced loads, accordingly.
• this has also the drawback that, in such a case, said balls tend, under the action of the centrifugal force, to form a single row of non- overlapping balls.
• a further improvement that is achieved thanks to said provision of a plurality of hollow bodies lies in the possibility of arranging said hollow bodies in contact with the side walls, ie. the front and/or back walls of the drum ( Figure 7), instead of having them arranged on the cylindrical surface thereof, where they would bring about the drawback of occupying a large portion of the space that is usually reserved to the inlet/outlet perforations provided for the passage of the wash liquor.
• Figure 7 illustrates an embodiment provided with only two hollow bodies, but it will be appreciated that such an architecture may obviously be extended to include a greater number of hollow bodies arranged on the same side wall of the drum. Such an improvement extends to include both the case in which the hollow bodies have their lobes arranged on common radii, as this is shown in Figure 7, and the case in which said hollow bodies have their lobes arranged on different radii, as this is shown in Figure 7a.
• lobed hollow bodies similarly apply also to the case in which one or more lobed hollow bodies are replaced, for each one of said hollow bodies, with a corresponding plurality of circular hollow bodies which may be either co ⁇ planar, and therefore provided with a different radius and fitted within each other, or arranged laterally in a side-by- side disposition, with their respective centers Dl, D2, D3 in an off-center alignment with respect to the axis of the drum.
• said combination of hollow bodies is manufactured as a single piece and, therefore, forms a cylinder, as it is shown by way of example in Figure 11, where also the cylindrical outer surface T of said piece comprising said hollow bodies is shown along with the projection on the exposed base of said cylinder of the three thichnesses d that delimitate said hollow bodies from each other.
• a further advantageous improvement of the present invention consists also in the use of movable balancing weights that have the shape of a thick disk and are capable of being rotated inside said hollow bodies having a cross-section that is substantially similar to the cross-section of said disk D ( Figure 8) . It is in fact widely appreciated that, as can be easily demonstrated, for an equal total volume occupied by the portion of hollow body filled with movable balancing weights, the weight of said movable balancing weights is greater if the latter are actually given such a disk-like shape than if they are given a ball-like shape, the most appropriate shapes and sizes being used in both cases in connection with the cross- section of the respective hollow bodies.
• a further improvement consists in the use of movable balancing weights which, instead of being constituted by a plurality of separate, distinct solids, are formed by a thick fluid mass, preferably a liquid which has the purpose of sustaining the movement of and in which there are borne a high quantity of very small, high specific-gravity particles, such as sand, metal chips or powder, etc.
• Such a combination would have the advantage of simplifying the construction of the movable balancing weights, while further improving the balancing capability, not only for the fact that a balancing mass provided in this way would not suffer from the discontinuities of distinct movable weights, but also for the fact that, under certain conditions, the ratio of the produced mass to the occupied volume may turn out to be still better than the one achievable in the afore illustrated case of the movable balancing weights being shaped as thick disks.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Main Body Construction Of Washing Machines And Laundry Dryers (AREA)
• Accessory Of Washing/Drying Machine, Commercial Washing/Drying Machine, Other Washing/Drying Machine (AREA)
• Rolls And Other Rotary Bodies (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=11394858

Family Applications (1)

Country Status (7)

Families Citing this family (4)

Family Cites Families (3)

• 1994
  • 1994-01-28 IT IT94PN000005A patent/ITPN940005A1/it unknown
• 1995
  • 1995-01-10 WO PCT/EP1995/000068 patent/WO1995020702A1/en active IP Right Grant
  • 1995-01-10 CA CA002173471A patent/CA2173471A1/en not_active Abandoned
  • 1995-01-10 ES ES95905617T patent/ES2121341T3/es not_active Expired - Lifetime
  • 1995-01-10 EP EP95905617A patent/EP0740716B1/de not_active Expired - Lifetime
  • 1995-01-10 DE DE69503356T patent/DE69503356T2/de not_active Expired - Fee Related
  • 1995-01-10 JP JP7519855A patent/JPH09508044A/ja not_active Ceased

Non-Patent Citations (1)

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