EP1882771A1

EP1882771A1 - Laundry machine with a fluid balance ring

Info

Publication number: EP1882771A1
Application number: EP06117835A
Authority: EP
Inventors: Stefano Galassi; Giovanni Colombera; Marco Giovagnoni
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2006-07-25
Filing date: 2006-07-25
Publication date: 2008-01-30
Anticipated expiration: 2026-07-25
Also published as: PL1882771T3; WO2008012076A1; EP1882771B1

Abstract

A laundry machine (1) having: a drum (5) rotating about a rotation axis (6); a rotary shaft (8) supporting the drum (5) and coaxial with the rotation axis (6); a spider (9) connected rigidly to the rotary shaft (8) and the drum (5) to connect the rotary shaft (8) and the drum (5) mechanically; and a fluid balance ring (10) fitted to the drum (5), coaxially with the rotation axis (6), and fitted rigidly to the spider (9).

Description

TECHNICAL FIELD

The present invention relates to a laundry machine with a fluid balance ring.
The fluid balance ring according to the present invention may be used to particular advantage in a washing machine, to which the following description refers purely by way of example.

BACKGROUND ART

Washing machines are known to comprise a fluid balance ring fitted to the drum to correct unbalance of the drum. More specifically, in known solutions, the fluid balance ring is fitted to an open front surface of the drum facing the loading/unloading door, comprises at least one annular chamber filled partly with liquid (normally water or water with added salt), and provides for reducing unbalance at high speed, caused by off-centred items inside the drum. One example of such a situation is a bundle of towels located on one side of a rotating washing machine drum. When the drum rotates at high speed, the unbalance produced by the towels is counteracted by the fluid inside the balance ring.
One example of a washing machine with a fluid balance ring is described in US6327732B1 , which relates to a fluid balance ring comprising a number of partitions forming a circular circumferential array of sub-chambers; and each partition has a spring-controlled valve movable, in response to the centrifugal force of the rotating balance ring, from a closed position preventing fluid flow through the partitions, to an open position permitting fluid flow through the partitions.
In known washing machines with fluid balance rings, performance of the rings is not always entirely satisfactory and is invariably below expectations.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a laundry machine with a fluid balance ring, designed to improve balancing performance, to eliminate the aforementioned drawbacks, and which is cheap and easy to produce.
According to the present invention, there is provided a laundry machine with a fluid balance ring, as claimed in the accompanying Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a schematic side view of a washing machine in accordance with the present invention;
Figure 2 shows a schematic view in perspective of a drum of the Figure 1 washing machine;
Figure 3 is an exploded view in perspective of the Figure 2 drum;
Figure 4 shows a schematic section of a portion of a fluid balance ring of the Figure 2 drum.

PREFERRED EMBODIMENTS OF THE INVENTION

Number 1 in Figure 1 indicates as a whole a washing machine comprising a casing 2 resting on a floor 3 on a number of feet 4. Casing 2 supports a revolving drum 5 (defining a wash tub) which rotates about a horizontal rotation axis 6 (in alternative embodiments not shown, rotation axis 6 may be tilted or vertical), and front access to which is closed by a door 7 hinged to casing 2.
As shown in Figures 2 and 3, drum 5 is supported on a rotary shaft 8, coaxial with rotation axis 6, with the interposition of a spider 9 connected rigidly to rotary shaft 8 and drum 5 to connect rotary shaft 8 and drum 5 mechanically.
A fluid balance ring 10 is fitted to drum 5, coaxially with rotation axis 6, to rotate about rotation axis 6 together with drum 5. More specifically, fluid balance ring 10 is fitted rigidly to spider 9, and is therefore located at the closed rear end of drum 5 opposite the open front end facing door 7.
Preferably, thought not necessarily, spider 9 has a central hub fitted to rotary shaft 8; and three spokes 11, each of which is connected rigidly at the outer end to a portion of drum 5, e.g. by means of two screws (not shown) inserted through two holes formed through spoke 11 and screwed inside two threaded holes formed through drum 5. In an alternative embodiment not shown, spider 9 may comprise a different number of spokes 11 (e.g. 2, 4 or 5). According to a preferred embodiment, fluid balance ring 10 is connected to each spoke 11 of spider 9 by a connecting bracket 12 having at least one through hole 13, and by at least one screw 14 which is inserted through hole 13 in connecting bracket 12 and screwed inside a threaded hole 15 formed through spoke 11 of spider 9. Obviously, the fluid balance ring 10 could be connected in other ways to the spider 9.
In a preferred embodiment shown in Figure 4, fluid balance ring 10 has a number of annular chambers 16, each of which is hydraulically isolated from the other annular chambers 16, is coaxial with rotation axis 6, and is filled partly with a liquid 17 (normally water or water with added salt). Fluid balance ring 10 preferably has a large number of annular chambers 16 (e.g. eleven, as shown in Figure 4, or more generally at least nine) to reduce the noise produced by fluid balance ring 10 as it rotates.
Testing and analysis confirm excellent balancing of drum 5 of washing machine 1 as described above, by virtue of fluid balance ring 10 being fitted rigidly to spider 9.
More specifically, being machined, spider 9 is precision manufactured and therefore precisely coaxial with rotation axis 6. Consequently, fluid balance ring 10 is also precisely coaxial with (of negligible eccentricity with respect to) rotation axis 6, which is indispensable for ensuring effective balance.
Moreover, being extremely rigid, spider 9 bends very little in use, and so undergoes no noticeable deformation in the opposite direction to the eccentricity of the load in drum 5 (unlike drum 5, which is made of welded and/or riveted sheet metal), thus enabling fluid balance ring 10 to operate in the best possible conditions. In other words, if fluid balance ring 10 is subjected in use to deformation in the opposite direction to the eccentricity of the load in drum 5, then the efficiency of fluid balance ring 10 is impaired. The highly rigid nature of spider 9, however, provides for eliminating or at least minimizing in-service deformation of fluid balance ring 10.
In short, the above solution allows a highly efficient fluid balance ring 10 to be fitted to spider 9 with no misalignment at either the assembly stage (precision assembly) or in working conditions (superior balancing performance) when drum 5 bends under the effect of an unbalanced load.
It should be pointed out that, by locating fluid balance ring 10 at the closed rear end of drum 5 opposite the open front end facing door 7, substantially no noise produced by liquid 17 inside fluid balance ring 10 is noticeable by the user when drum 5 is rotated manually.
Finally, another important point to note is that washing machine 1 as described above is cheap and easy to produce, by involving only minor alterations to a known washing machine and no new component parts.
Though particularly advantageous for a washing machine, the above structure also applies to any other kind of laundry machine, such as a drier or a washer-drier.

Claims

A laundry machine (1) comprising:
a drum (5) rotating about a rotation axis (6);

a rotary shaft (8) supporting the drum (5) and coaxial with the rotation axis (6);

a spider (9) connected rigidly to the rotary shaft (8) and the drum (5) to connect the rotary shaft (8) and the drum (5) mechanically; and

a fluid balance ring (10) fitted to the drum (5) and coaxial with the rotation axis (6);

the laundry machine (1) being characterized in that the fluid balance ring (10) is fitted rigidly to the spider (9).
A laundry machine (1) as claimed in Claim 1, wherein the spider (9) has a number of spokes (11), each of which is connected rigidly at an outer end to a portion of the drum (5); and the fluid balance ring (10) is connected to each of the spokes (11) of the spider (9).
A laundry machine (1) as claimed in Claim 2, wherein the fluid balance ring (10) has a number of connecting brackets (12), each having at least one through hole (13); and a number of screws (14), each inserted through the through hole (13) in a respective connecting bracket (12) and screwed inside a threaded hole (15) formed through a respective spoke (11) of the spider (9).
A laundry machine (1) as claimed in Claim 1, 2 or 3, wherein the fluid balance ring (10) comprises a number of annular chambers (16), each of which is hydraulically isolated from the other annular chambers (16), is coaxial with the rotation axis (6), and is partly filled with a liquid (17).
A laundry machine (1) as claimed in Claim 4, wherein the fluid balance ring (10) has at least nine annular chambers (16).
A laundry machine (1) as claimed in Claim 4, wherein the fluid balance ring (10) has eleven annular chambers (16).