WO1993013257A1

WO1993013257A1 - Laundry machine agitator

Info

Publication number: WO1993013257A1
Application number: PCT/NZ1992/000007
Authority: WO
Inventors: Gerald David Duncan
Original assignee: Fisher & Paykel Limited
Priority date: 1991-12-20
Filing date: 1992-12-18
Publication date: 1993-07-08
Also published as: BR9206965A; MX9207475A; KR940703951A; CA2126204A1; AU3174693A; JPH07502182A

Abstract

A vertical axis agitator for a laundry machine. The agitator has an upper and a lower group of radial agitating blades. The blades of the upper group are fixed to the agitator column at their upper end and are free to flex during agitation at their lower end. The inner ends of the blades of the lower group are attached to the agitator column near its base and have their outer ends free to flex during agitation in the agitation phase of a wash cycle. The flexible blades assist in producing a roll-over washing pattern.

Description

"LAUNDRY MACHINE AGITATOR"

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention relates to laundry machine agitators and/or laundry machines including such agitators.

(2) DESCRIPTION OF THE PRIOR ART It is known that the most efficient way to wash clothes in an automatic laundry machine having a vertical axis agitator is to provide a cyclical roll over movement pattern, or toroidal movement pattern, of clothes during agitation phases of the washing cycle. The cyclical roll over movement pattern involves moving the clothes downwardly adjacent to the central column of the agitator, then radially outwardly from the oscillating agitator blades, then in an upward direction adjacent to the wall of the washing receptacle or spin tub, and then back inwardly towards the upper end of the central column of the agitator. This motion is preferably substantially continuous so that the clothes are then continually turned or rolled over while also being moved back and forth slightly by the agitator. Conventional agitators having fixed, rigid, radial blades are not good at providing the type of roll over pattern described above, especially when heavy loads are being washed.

In order to achieve the roll over pattern of movement, agitators have been designed having two separate portions, an upper portion to provide the downward movement of the clothes adjacent to the central column of the agitator and a lower portion to provide the outward radial movement away from the central column of the agitator. The upper portions of these agitators has a spiral vane and a one way clutch means is provided for rotating the upper portion in a single direction while the lower portion rotates in alternate directions to provide the agitation motion. Such agitators are disclosed in Ruble U.S. Patent No. 3,987,652, Platt US Patent No. 3,987,508 and Bark et al. US Patent No. 4,779,431, all assigned to Whirlpool Corporation. The requirement of a two piece agitator is disadvantageous, since the one way clutch means or additional drive means needs to be provided, increases the number of moving parts required in the machine and adds to the cost of manufacture. The provision of the additional moving parts therefor increases the cost of producing the machine, increases the risk of mechanical failure, and adds to the cost of maintaining the machine.

BRIEF SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to go some way toward overcoming the above disadvantages or to provide a laundry machine agitator and/or a laundry machine including such an agitator which will at least provide the public with a useful choice.

Accordingly in one aspect the invention may broadly be said to consist in a vertical axis agitator for location within a washing receptacle for containing washing liquid and articles to be washed, said agitator having a central column fixed to and concentric with a lower skirt characterised in that on said central column portion two groups of agitating radial blades are provided, an upper group comprising a plurality of upper blades each upper blade being fixed to said central column at an upper end thereof, and the lower part of each blade being free of said central column and being flexible so as to flex during agitation of articles in said receptacle and a lower group of lower blades, an inner portion of each of said lower blades being fixed to said column or said skirt adjacent to the intersection of said column and said skirt, each said lower blade having a resiliently flexible movable outer portion clear of said central column and of said skirt, said movable portions being moveable by flexure during agitation of said agitator in the washing process.

In a further aspect the invention consists in a laundry machine having a washing receptacle, a spin tub in said washing receptacle adapted to receive articles to be washed, an agitator in said spin tub, driving means to rotate said agitator in forward and reverse directions for washing and to rotate said agitator and said spin tub unidirectionally for spinning and wherein said agitator is constructed arranged and operable substantially as set forth in the preceding paragraph. To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

One preferred form of the invention will now be described with reference to the accompanying drawings in which;

Figure 1 is a cross section of an agitator within a spin tub in turn within a receptacle for washing liquid and articles to be washed all forming part of a laundry machine. Only one agitating blade in each of an upper and lower group is shown for clarity;

Figure 2 is a cross section on the lines ll-ll Figure 1;

Figure 3 is a cross section on the line Ill-Ill Figure 1; and Figure 4 is a cross section on the line IV-IV Figure 1.

DETAILED DESCRIPTION

Referring to the drawings, Figure 1 shows an agitator 1 which forms part of a laundry machine constructed for example in accordance with US Patent Specification No. 4,813,248. The agitator 1 is provided within a rotating perforated spin tub 2 which in turn is within a washing receptacle 3. An interconnecting mechanism 4 is provided to enable interconnection between the agitator 1 and the spin tub 2 when there is little or no washing liquid in the container 3 and when there is sufficient liquid in the container 3 a float 5 disconnects the agitator 1 from the spin tub 2 thus permitting agitation of the agitator in forward and reverse directions under operation of an electric motor (not shown) connected to shaft 6.

The present invention is concerned with the provision of two groups of blades represented by upper blade 10 attached to an upper part of the central column 11 of the agitator 1 and a lower blade 15 connected partly to the lower part of the column 11 and partly to a flared part 16 of a skirt 17. There are preferably three blades 10 in the upper group and three blades 15 in the lower group and these blades are preferably spaced symmetrically in plan view that is to say arranged at 120° intervals.

The central column 11 also has a series of slots 20 which are arranged so that water or liquid is drawn into these slots and discharged from the lower periphery 21 of the skirt 17.^' As may be seen from Figure 1 the upper blades 10 are attached by an upper portion 25 thereof to the central column 11 but the lower portion 26 of each blade is arranged to be separated as shown at 27 and spaced away from the central column 11 and is formed of a flexibly resilient plastics material, for example polypropylene and consequently the lower portion 26 will flex as the agitator is moved in one direction away from the direction of movement of the agitator and then flex in the opposite direction when the agitator is reversed. The cross section of the section 26 is shown in Figures 2 and 3 where Figure 2 represents the upper part 30 and Figure 3 represents the lower part 31 at the sections II and III respectively. Lower part 31 has edges 32 which are substantially the same thickness as upper part 30, but the thickness of the central portion of lower part 31 is less than that of part 30. This reduces the rigidity of the lower part which assists in allowing it to flex.

It will be seen from the drawing that the blades 10 are considerably longer in an axial direction as compared with the radial width thereof, the length being of the order of at least three times the width thereof. The upper edge 35 of the blade 10 is preferably to a radius of 300mm sweeping in a 30mm curve 36 to a parabolic or hyperbolic curve 37 and terminating in a rounded end 38. The inner edge 39 is preferably straight with a slight slope downwards outwardly away from the column 1 as between the upper and lower part thereof. The lower blades 15 each spring partly from a lower part 40 of the central column and partly from the flared portion 16 of the skirt 17. In this case the blade has an upper portion 42 part way up the central column 11 leading in a curve to an upper edge of blade 15 which leads to a rounded end 43 and then returning to a lower part of the flared portion 16 of the skirt 17. The cross section on the line IV-IV is shown at 45, Figure 4 and can be seen to have parallel sides with rounded ends. Again the blade is made of a flexibly resilient material, for example polypropylene arranged to flex in a direction parallel to the plane of the blade, that is to in and out of the drawing as shown in Figure 1 and away from the direction of rotation of the agitator 1 during agitation. The lower edge 46 is spaced away and curves generally upwardly outwardly away from the skirt 17.

The operation of the above construction is as follows.

The receptacle 3 is filled with washing liquid for example water to which a washing additive has been added and articles of clothing placed in the spin tub

2 for washing. The washing liquid level is, for a full load, about the level 50 and if there is a very heavy load of clothes for example upwards of 7kg in the relative size of spin tub shown or in the event that a smaller spin tub to that shown in the drawing is used, the clothing tends to accumulate in the area marked 51 in the drawing. The result of this is that there can be a considerable difference in soil removal efficiency varying sometimes as much as 11%. However with the present invention the blades 10 and 15 cause the articles being washed to move in a rolling over action or pattern to result when agitation occurs, such action being illustrated by the arrows 53 and 54. This action is due to a stirring/pumping action caused by the blades 10 flexing so as to tend to direct washing liquid downwardly followed by an upward and an outward movement due to the blades 15 being more flexible along the top edge than the bottom and to their being inclined away from the skirt towards the outer ends. Thus a rollover pattern takes place which is the desired result. Because the blades 10 and 15 are radial then moulding of the agitator including the blades is a relatively simple process. Furthermore because the agitator and blades are a one piece moulding, costs are reduced because the manufacturing costs of a one piece member are lower than that for multiple portion agitators. Also, the one piece moulding provides an agitator which has increased reliability and requires less maintenance. Thus the present invention has considerable advantages.

Claims

CLAIMS:

1. A vertical axis agitator for location within a washing receptacle for containing washing liquid and articles to be washed, said agitator having a central column fixed to and concentric with a lower skirt characterised in that on said central column portion two groups of agitating radial blades are provided, an upper group comprising a plurality of upper blades each upper blade being fixed to said central column at an upper end thereof, and the lower part of each blade being free of said central column and being flexible so as to flex during agitation of articles fn said receptacle and a lower group of lower blades, an inner portion of each of said lower blades being fixed to said column or said skirt adjacent to the intersection of said column and said skirt, each said lower blade having a resilientiy flexible, movable outer portion clear of said central column and of said skirt, said movable portions being moveable by flexure during agitation of said agitator in the washing process.

2. A vertical axis agitator as claimed in claim 1 wherein each said upper blade is axially long compared with its width.

3. A vertical axis agitator as claimed in claim 1 or claim 2 wherein the lower part of each upper blade is spaced apart from said central column.

4. A vertical axis agitator as claimed in any one of the preceding claims wherein each said lower blade is wide radially compared with the height thereof.

5. A vertical axis agitator as claimed in any one of the preceding claims wherein the lower edge of each said lower blade generally curves away from said skirt.

6. A vertical axis agitator as claimed in any one of the preceding claims wherein said central column also contains vertical slots therein to enable washing liquid to be drawn into the central hollow portion of said column for distribution from a lower part of said skirt.

7. A vertical axis agitator as claimed in any one of the preceding claims wherein said groups of blades each comprises three blades arranged symmetrically about the agitator axis.

8. A vertical axis agitator as claimed in any one of the preceding claims wherein said central column terminates in a flaring connection between the central column and said skirt.

9. A vertical axis agitator as claimed in any one of the preceding claims wherein the outer surface of said skirt slopes downwardly outwardly.

10. A vertical axis agitator as claimed in any one of the preceding claims wherein each said upper blade has a central portion bounded by outer edges, said outer edges being thicker than said central portion at a lower part of each said upper blade.

11. A vertical axis agitator as claimed in any one of claims 4 to 9 wherein each said lower blade is fixed to said skirt and said column and each said lower blade has an upper edge, said upper edge being more flexible in a direction perpendicular to the plane of the blade than said lower edge.

12. A vertical axis agitator substantially as herein described with reference to and as illustrated by the accompanying drawings.

13. A laundry machine having a washing receptacle, a spin tub in said washing receptacle adopted to receive articles to be washed, an agitator in said spin tub, driving means to rotate said agitator in forward and reverse directions for washing and to rotate said agitator and said spin tub unidirectionally for spinning and wherein said agitator is as claimed in any one of claims 1 to 11.

14. A laundry machine substantially as herein described with reference to and as illustrated by the accompanying drawings.