EP0672778A1

EP0672778A1 - Washing machine

Info

Publication number: EP0672778A1
Application number: EP95301450A
Authority: EP
Inventors: Grahame Russell Key
Original assignee: Hoover Ltd
Current assignee: Hoover Ltd
Priority date: 1994-03-15
Filing date: 1995-03-06
Publication date: 1995-09-20
Also published as: GB9404938D0; GB2287475A

Abstract

A gasket for sealing the tub of a washing machine to its outer cabinet comprises an annular elastomeric gasket (20) having opposed peripheries fixed respectively to the tub and cabinet. The gasket (20) is formed with an annular corrugation (21) and an annular zone comprising a series of corrugations (22) each extending axially of the gasket. The corrugations (22) enable those portions of the gasket which lie generally parallel to the instantaneous direction of movement of the tub to exhibit a degree of resilient flexibility, and so reduce vibratory forces being transmitted from the tub to the cabinet.

Description

This invention relates to a gasket for sealing the tub of a washing machine to its outer cabinet or shell.
Washing machines (including combined washing/drying machines) generally comprise an assembly which includes a tub and a perforated drum mounted within the tub for rotation about its axis, which is typically horizontal (although in some machines it is vertical). The tub-and-drum assembly is resiliently mounted within an outer cabinet or shell, and the tub and drum are both open at one end so that clothes or other articles to be washed can be loaded through an opening in the front of the cabinet (or top of the cabinet, in the case of a vertical-axis machine), which opening is provided with a hinged door. The tub is sealed to the cabinet by an annular gasket which has opposite peripheries fixed respectively to the tub and to the cabinet.
These tub-to-cabinet sealing gaskets are generally of bellows-like or corrugated form (typically S-shaped in section), intended to give the gasket flexibility to accommodate oscillatory movements of the tub-and-drum assembly relative to the cabinet, in use of the machine particularly during the centrifugal (or spin) phase of its operation. The locus of displacement of the tub axis, in a plane transverse to that axis, is approximately circular or elliptical. At any instant, there are diametrically opposed portions of the gasket which extend generally transverse to the instantaneous direction of movement of the tub: these portions are able to distort resiliently because of the annular corrugations of the gasket: however, there are other portions of the gasket which lie generally parallel to the instantaneous direction of movement; these portions are in shear and exhibit considerable stiffness and accordingly transmit vibratory forces to the cabinet. Oscillatory rotational movement may also be superimposed on this cyclic displacement, resulting in a couple being transmitted to the cabinet due to the shear stiffness of the gasket. The latter effects have been exacerbated in that the stiffness in shear of tub-to-cabinet gaskets has increased over the years owing to the use of materials better able to resist corrosive detergents, and to the incorporation in the gasket of ports coupled to fixed ducts for conveying water or hot air into the tub.
In accordance with this invention, there is provided a washing machine tub-to-cabinet gasket, the gasket being of generally annular form and having opposed peripheries for fixing respectively to the tub and cabinet of a washing machine, and the gasket further including at least one circumferential zone which extends for a substantial proportion of the gasket periphery, the radius of the gasket within said zone varying along the length of said zone.
The gasket in accordance with this invention therefore differs from hitherto known gaskets in that it includes at least one circumferential zone which is not a solid of rotation relative to its axis.
Preferably the radius of the gasket, within the or each said circumferential zone, varies in a cyclical manner.
Preferably the or each said circumferential zone of the gasket is formed with a series of corrugations oriented generally axially of the gasket. Preferably the corrugations are oriented at an angle to the gasket axis, of preferably 45°.
There may be a single said circumferential zone which extends the full width of the gasket, i.e. between the two opposed peripheries thereof, or the or each said circumferential zone may be limited to part of the full width of the gasket.
Preferably the or each circumferential zone extends around the full periphery of the gasket. However, the gasket may be formed with one or more radially-projecting ports for sealing to fixed ducts of the machine: the (or at least one) circumferential zone of the gasket is interrupted over the circumferential extent of the or each such duct.
Embodiments of this invention will now be described, by way of examples only, and with reference to the accompanying drawings, in which:

FIGURE 1 is a sectional view through a portion of a washing machine incorporating an embodiment of tub-to-cabinet sealing gasket in accordance with this invention;
FIGURE 2 is a section through the gasket, along the line II-II of Figure 1;
FIGURE 3 is a perspective view of a portion of the gasket of Figures 1 and 2; and
FIGURE 4 is a section, similar to Figure 2, through an alternative embodiment of washing machine tub-to-cabinet sealing gasket.

Referring to Figure 1 of the drawing, there is shown a tub-and-drum assembly 11 resiliently mounted within an outer cabinet 10 of a washing machine. The assembly 11 includes a tub 12 and a perforated drum 13 mounted within the tub for rotation about its horizontal axis. The tub-and-drum assembly 11 is resiliently mounted by means of a plurality of suspension units e.g. 14,15. The drum and tub 12 and 13 are open at one end, so that clothes or other articles to be washed can be loaded through an opening 16 in the front of the cabinet 10. The tub 12 is sealed around its open end to the opening 16 in the cabinet 10 by an annular elastomeric gasket 20, to prevent the egress of the water from the tub in use of the machine. The annular gasket has opposed peripheral rims which are fixed respectively to the tub 12 around its open end and to the cabinet 10 around its opening 16. A door 17 is hinged to the front of the cabinet 10, to close the opening 16 during use of the machine. The door 17 comprises a transparent glass or plastics bowl 18 which projects through the opening 16 and seals against the gasket 20.
Figures 1 to 3 show that the gasket 20 is formed with an annular corrugation 21: as previously discussed, this gives the gasket flexibility such that those portions of the gasket which extend generally transverse to the instantaneous direction of oscillatory movement of the tub, are able to distort readily. The gasket 20 is further formed with a series of corrugations 22 each extending or oriented generally axially of the gasket, and preferably as shown at an angle to the axis of the gasket: preferably this angle is approximately 45° (the axial direction of the gasket being indicated at A-A in Figure 3). The corrugations 22 are formed in a circumferential zone which may extend across the full width of the gasket (i.e. from one peripheral rim to the other), or may as shown be limited to part of the width of the gasket. Because of these corrugations 22, those portions of the gasket which lie generally parallel to the instantaneous direction of movement of the tub, exhibit a degree of resilient flexibility and so the transmission of vibratory forces and couples to the cabinet 10 is reduced.
Preferably the circumferential zone, which is formed with the corrugations 22, extends around full periphery of the gasket. However, Figure 4 shows an alternative embodiment of tub-to-cabinet gasket which differs from the embodiment of Figure 2 in that it has a radially projecting port 30 for sealing to a fixed duct of the washing machine. The circumferential zone of corrugations 22 extends around the full periphery of the gasket except for the circumferential portion which is occupied by the port 30.
Instead of corrugations 22, other forms of profiling may be used in the corresponding circumferential zone of the gasket, providing the zone exhibits a radius which varies, preferably cyclically, along its length circumferentially of the gasket. The circumferential zone therefore differs from being a solid of rotation, and gives improved flexibility to circumferentially-directed forces.

Claims

1) A washing machine tub-to-cabinet gasket, the gasket being of generally annular form and having opposed peripheries for fixing respectively to the tub and cabinet of a washing machine, and the gasket having at least one circumferential zone which extends for a substantial portion of the gasket periphery, the radius of the gasket within said zone varying along the length of said zone.

2) A washing machine tub-to-cabinet gasket as claimed in claim 1, in which the radius of the gasket, within the or each said circumferential zone, varies in a cyclical manner.

3) A washing machine tub-to-cabinet gasket as claimed in claim 2, in which the or each circumferential zone of the gasket is formed with a series of corrugations oriented generally axially of the gasket.

4) A washing machine tub-to-cabinet gasket as claimed in claim 3, in which the corrugations are oriented at an angle of 45° to the gasket axis.

5) A washing machine tub-to-cabinet gasket according to any preceding claim, in which the or each circumferential zone extends the full width of the gasket.

6) A washing machine tub-to-cabinet gasket according to claims 1 to 4, in which the or each circumferential zone is limited to part of the full width of the gasket.

7) A washing machine tub-to-cabinet gasket according to any preceding claim, in which the or each circumferential zone extends around the full periphery of the gasket.

8) A washing machine tub-to-cabinet gasket according to any of claims 1 to 6, formed with one or more radially-projecting ports for sealing to fixed ducts of the machine.

9) A washing machine tub-to-cabinet gasket according to claim 8, in which the or each circumferential zone is interrupted over the circumferential extent of the or each such duct.

10) A washing machine or combined washing/drying machine, which includes a tub-to-cabinet gasket according to any preceding claim.