GB2226335A - Outer drum for a washing machine - Google Patents

Abstract

An outer drum (2) for a washing machine, comprising a drum-shaped plastics moulding having a base (21), a wall (24) and an integrally-moulded upstanding diverter (27) of uniform thickness extending longitudinally along the wall; the moulding having an outlet port (60) adjacent the diverter (27) to receive water set in motion by rotation of the inner drum 2. Preferably a recess 25 whose curved cross section increases towards outlet 60 is disposed upstream of a concave diverter 27 to channel the wash water to the outlet. The diverter prevents concentrated detergent (entering in direction 8) from passing straight to outlet 60 and shields heater 7 from coins etc inadvertently added with the laundry. <IMAGE>

Description

Outer drum for a Washing Machine This invention relates to an outer drum for a washing machine. The outer drum supports an inner drum for rotation about a generally horizontal axis, and contains the wash liquid. The outer drum is usually open at the front for loading and unloading, and has a port for the exit of wash liquid.

The invention relates in particular to outer drums moulded from plastics material.

A problem associated with outer drums, or wash tubs as they are also known, for washing machines, within which the horizontally-mounted inner drum rotates, is that in operation, during a centrtfugtng stage, liquid extracted from the clothes passes through perforations in the cylindrical wall of the inner drum and is impelled by the rotation of the drum around and within the generally corresponding cylindrical wall of the outer drum. Such occluded liquid is difficult to collect so as to enable its disposal through a waste outlet.

In order to overcome this problem, plastics wash tubs are now generally moulded with a recessed longitudinal channel along the bottom. This recessed portion has, relative to the direction of rotation of the inner drum, a cross-section which includes on the one side, where the occluded waste liquid enters, a slope down to the floor of the recess and, on the other side, a vertical, or near-vertical, wall against which the impelled liquid is projected. This causes a turbulent effect such that the liquid collects at the bottom of the tub and then passes through a waste outlet in the wall of the tub. The recessed portion also houses the heating element for the washing machine.

A disadvantage with this arrangement is that foreign objects, such as metal coins, which can inadvertently be left in a load of clothes to be washed, can, if released, pass through into the space between the inner and outer drums, fly around as the drum rotates, and become trapped within the confined spaces between the drums. Here, especially during a centrtfugtng operation, the energy of the inner drum is sufficient to cause any trapped objects to pierce or split the wall of the outer drum allowing wash liquid to be leaked from the machine. Other, freely moving, foreign objects can strike the heating element, often causing significant damage.

A further disadvantage of this arrangement is that it requires the outlet port of the outer drum to be situated at the lowest point to allow the wash liquid to fall into the outlet. A significant volume of detergent, immediately after it enters the outer drum at the beginning of a wash cycle, falls into the recess and then the outlet, and is not mixed with the water which subsequently enters. It is therefore unavailable for processing, and is thus wasted.

Accordingly, the invention provides an outer drum for a washing machine, comprising a drum-shaped plastics moulding having a base, a wall, and an integrally-moulded upstanding diverter extending longitudinally along the inside of the wall, the moulding having an outlet port adjacent the diverter so that, in operation, wash liquid is directed to the outlet port.

The flow of liquid around the outer drum is broken up by the diverter, acting as a barrier, which directs the flow through the outlet port. The diverter does not form part of the outer wall, and accordingly any impact damage will not lead to fluid leakage. Also, the diverter may be arranged to protect from impact damage any suitably-positioned heater for a washing machine. A further advantage is that the diverter prevents the initial flow of detergent from entering the waste outlet, at least until it has been diluted with a further flow of water. Further still, there is no longer any need for a large recessed channel, so that the detergent loss is minimized in washing machines.

Although a deep recess is not required, the wall nevertheless preferably has a longitudinal recess alongside the diverter, and communicating with the outlet port, for housing safely any solids hitting the diverter and for assisting the channelling of wash liquid through the outlet port. It is desirable to trap rotating solids, yet to ensure that the trapped solids do not interfere with the rotation of the inner drum.

The best performance with the draining of the wash liquid is obtained when the outlet port is adjacent the end of the diverter nearer the base.

One preferred form of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which Figure 1 is a vertical section through the centre line of a washing machine embodying the invention, illustrating the general disposition of its principal parts; Figure 2A is a perspective view, partly in section, of the interior of the moulded plastics outer drum or wash tub of the machine of Figure 1; and Figure 2B is a partial section on the line A-A of Figure 2A.

A front-loading washing machine 1 comprises a cabinet housing a wash tub 2 and a rotary inner drum 3. Access to the interior of the drum 3 is provided through a door 4. The inner drum 3 has a perforated cylindrical wall 31 about an axis 5, and a base 32 to which is attached a driving member comprising a spider support 33 attached to a driving shaft 35 rotatable by a motor 36 via a driving pulley 37.

The drum-shaped wash tub 2 is formed as an integral plastics moulding from a glass-coupled polypropylene material. The tub has a conventionally-shaped base 21 for rotatably supporting and accommodating the base 32 of the inner drum such that in operation there is a minimal annular space between the two drums. This prevents the entrapment of solids.

A diverter 27 projects inwardly from the wall 24 of the wash tub, to form a barrier for wash liquid (approaching in the direction of arrow 9) which is impelled by the rotation of the inner drum. The diverter is generally part-conical, being concave from the direction of wash liquid flow during centrifuging. The diverter has uniform thickness but its radius of curvature increases progressively from the front to the rear of the wash tub, i.e. progressively in the direction of arrow 26. The wall 24 of the tub has a recess 25 of part-conical form located alongside the diverter so as to provide a continuous, smoothly curved channel for the diversion of wash liquid in the direction of arrow 26 through an outlet port 60.

At its inner end (i.e. the end nearer the base of the drum 2) the diverter 27 merges, in full depth, with a part-annular step 23, forming part of the drum 2, in which part of the outlet port 60 is located, the other part being formed by the run-out point for the part-conical recess 25.

The edge 28 of the diverter is thus generally parallel with the surface of a shoulder 22 which in turn merges with the base 21 of the drum. The shoulder 22 has a smooth cylindrical surface about the inner drum axis, to ensure a minimum clearance from the inner drum, as referred to above.

At its outer end (i.e. the end nearer the tub opening) the leading edge 29 of the diverter terminates just short of the associated part 251 of the recess 25 which slopes upwardly to the general level of the tub wall (see especially Figure 2B).

With reference to Figure 2A, a heating element 7 is located such that an associated support plate 70 is held between, on the one hand, two lntegrally-moulded projections 71 and on the other hand a projection 72 formed on the outside of an overhang portion of the tub moulding. Its location adjacent the diverter on the opposite side to the wash liquid flow in the direction of arrow 9 ensures its protection from any objects, solid or otherwise, impel led by rotation of the inner drum.

Whereas the generally cylindrical wall 24 of the wash tub opens out slightly from the rear to the front, the diverter and its associated recess taper broadly outwardly towards the rear.

Accordingly the impel led wash liquid, which would otherwise tend to flow towards the open front of the drum, is directed to the rear into the outlet 60, thus improving the rate of drainage of the liquid.

Conveniently the curved wall of the diverter is inclined at an acute angle to the axis 5, again assisting in the discharge of wash liquid.

In a washing operation, the initial flow of highly concentrated lye enters the outer drum in the direction of arrow 8 and is thus prevented from entering the recess 25, where it would effectively be unavailable for use, by the upstanding diverter.

The wash tub 2 is manufactured as a single plastics moulding using, for the diverter and recess, complementary moulds which are separable in opposite directions along the axis of the moulding parallel to the inner drum axis 5. Thus the moulding halves are readily separated in this manner and, accordingly, the diverter has uniform thickness.

Although, in the preferred example described, the diverter and recess together provide a part-contcal path widening towards the outlet port 60, other configurations would be possible as alternatives. It is not essential, for example, to provide the recess 25, and the diverter 27 need not be curved. Further, although the shoulder 22 is provided in the preferred example it would be possible for the recess 25, and with it the diverter 27, to continue rearwardly further towards the base of the tub.

Although the invention has been illustrated in the form of a washing machine without a drier, it is to be understood that the term "washing machtne" is intended to include washer-driers.

Claims (13)

1. An outer drum for a washing machine, comprising a drum-shaped plastics moulding having a base, a wall, and an integrally-moulded upstanding diverter extending longitudinally along the inside of the wall, the moulding having an outlet port adjacent the diverter so that, in operation, wash liquid is directed to the outlet port.

2. An outer drum according to Claim 1, in which the outlet port is adjacent the end of the diverter nearer the base.

3. An outer drum according to Claim 1 or 2, in which the wall has a longitudinal recess immediately adjacent the diverter and communicating with the outlet port, for trapping any solids and for assisting the channelling of wash liquid through the outlet port.

4. An outer drum according to Claim 3, in which the recess and the diverter together form a channel for directing the wash liquid to the outlet port during a centrtfughng operation.

5. An outer drum according to Claim 4, in which the channel has a continuously curved inner surface.

6. An outer drum according to Claim 5, in which the channel has a generally conical inner surface.

7. An outer drum according to any preceding Claim, in which the diverter is curved about a longitudinal axis, the outlet port being on the side closer to that axis.

8. An outer drum according to any preceding Claim, in which the wall has an tnwardly-projecttng, part-cylindrical shoulder adjacent the base.

9. An outer drum according to Claim 8, in which the outlet port is formed in an annular, radlally-extendtng step between the shoulder and the remainder of the wall.

10. A washing machine comprising an outer drum according to any preceding Claim, and a rotatable inner drum whose direction of rotation during a centrifuging operation is such as to impel wash liquid against the diverter and thence out through the outlet port.

11. A washing machine according to Claim 10, comprising a heater housed in internal formations moulded integrally in the outer drum on the side of the diverter opposite that of the outlet port, so that the heater is shielded by the diverter from any solids impelled by the drum.

12. An outer drum substantially as described herein with reference to Figures 2A and 2B of the accompanying drawings.

13. A washing machine, substantially as described herein with reference to the accompanying drawings.