US3066521A - Washing machine with improved agitation - Google Patents

Description

Dec. 4, 1962 J. GILLESSEN WASHING MACHINE WITH IMPROVED AGITATION Filed April 27, 1960 INVENTOR JOSEF LEON/mo 0/41.: s selv 5 m ha V 4 Ill? n n2 n nrra was 7 s United States Patent Ofihce Patented K ee, l, lib- 3,4?66521 WASHING MACHINE WlTH IMPRGVED AGITATION Josef Leonard Giliessen, Dusseldorf, Germany, assignor to Maschinenfahrilt Peter Pfenningsherg Gannbll, Dusseldorf-Oberiiassel, Germany Filed Apr. 27, 196i Ser. No. 25,6?) Claims priority, application Germany May 29, E59 9 Claims. (Cl. 6823) This invention relates to Washing machines intended especially for household use and having washing drums which are rotated about vertical axes, and have charging apertures in their tops There are known washing machines in which, during the washing process, the material being washed is handled mechanically by a washing stirrer, also called a pulsator or agitator. In most cases the drum remains stationary during this process. After the washing process has come to an end, the drum which is able to rotate about a vertical axis, and in certain cases the agitator too, are rotated rapidly, so that when the outlet is opened the material may be spin-dried. This washing process requires a comparatively high ratio of washing liquid to material being washed. Besides this, during the process the material being washed is subject to a considerable amount of wear due to the inflexible movement of the agitator.

In the case of another known washing machine, in which the washing container is upright, the material to be washed is constantly turned by a stream of liquid which is directed radially in relation to the container floor and climbs up its walls, the container being at rest. Thus the washing is handled mechanically too, whilst the washing liquid flows repeatedly back to a pump with which the machine is provided and by means of which the liquid is again introduced at the floor of the con tainer. This process is in essence less damaging than the first. But a powerful flow of liquid is required for the washing to be treated effectively. In this case also a high ratio of washing liquid to material being washed is necessary. A powerful pump is required also. Apart from this it has come to light that, in relation to the mechanical agitator, this device is not very effective and so, in general, longer periods of washing are necessary.

The problem with which the present invention is concerned lies in providing a washing machine, especially intended for household use, which does not have the shortcomings mentioned above and which, although having a most simple form of construction, none the less makes effective laundering of even delicate articles possible.

According to the present invention, the floor of the drum of a washing machine having a drum which is rotatable about a vertical axis slopes upwards from the inside towards the periphery and the drum has a variable speed drive. The floor of the drum is preferably conical. The drum is revolved at a high speed and then again at a low speed several times whilst the washing process is under way. The effect is that the material to be washed repeatedly climbs up the floor of the washing drum and then falls back towards the center of the drum again. For, when the speed of rotation of the drum increases, centrifugal force acts on the material to be washed, one component of which takes effect in a direction parallel to the floor of the drum as a result of which the material climbs upwards, whilst its other component is normal to the surface of the floor of the drum and this presses the material to be washed against it. The floor of the drum is preferably provided with corrugations in the manner of a washboard. These by preference should run concentrically with the axis of and rotation of the drum. Whenever the material to be washed ascends or descends the floor of the drum, the floor has the effect of a washboard on it, this effect being at the same time augmented by means of the additional pressing of the material against the floor whilst it is ascending.

In a washing machine which has a washing drum provided with perforations, and which is housed in an outer container, the washing drum has, in accordance with a further feature of the invention, an unperforated roof in which the charging opening is situated. This roof is turned down slightly around the charging opening. The outer container conforms to the shape of the washing drum surrounding it completely, and at only a slight distance from it. At the top of the outer container there is a charging opening which may be closed by means of a cover. Thus when the speed of rotation of the drum increases, not only is the material to be washed pressed against the drum floor and thus at the same time lifted, but the washing liquid also is forced radially through the material to be washed. As a result of this the water enters the narrow annular space between the drum and the outer container via the perforations in the drum. Here the water climbs up to the top, returning once more to the drum via the charging aperture. In this manner a circulation of the washing liquid is effected without an additional pump being necessary for this purpose.

In order that the washing liquid can flow back into the charging opening of the drum roof via the roof, without being prevented by centrifugal force, there is a fixed baflle plate disposed above the Washing drum. This plate conforms to the shape of the drum roof and its outer edge is turned downwards and lies at a very small distance from the drum roof.

An example of a washing machine in accordance with the invention is illustrated in the accompanying drawing in which:

FIGURES l to 3 are diagrammatic vertical axial sections through the machine, each figure illustrating a different phase of the washing operation;

FIGURE 4 is a diagram showing some of the forces which arise during the washing operation; and

FTGURE 5 is a graph showing the relationship between the speed of rotation of the drum and time.

As shown in FIGURES 1 to 3, a Washing drum 1. which has perforations 2, is rotatable about a vertical axis. The drum has a floor 3 which ascends conically outwards. The floor 3 is provided with corrugations 3, like a washboard, which in this case are concentric with the axis of rotation of the drum. The drum has at the top an unperforated roof 4 having a central charging aperture 5'. The roof 4 is slightly turned down around the charging aperture. The floor 3 has a flange 6 to which a driving shaft 7 is attached. The shaft 7 is connected via a coupling 8 to a motor 9. The washing drum 1 is encased by an exterior container it which is constructed to conform to the shape of the drum and lies at all points at a slight distance from it. There is thus a space ill between the drum 1 and the exterior container It A roof 12 of the container 10 has a central charging aperture 13 which may be closed by means of a lid 14. The aperture 13 coincides with the charging aperture 5 of the drum 1. A drain 15 attached to the exterior wall of the container 10, which communicates with the inner space of the container, terminates in an outlet channel 17 for the washing liquid. The channel 17 has a shut-off valve 16. Above the washing drum 1 there is a baffle plate 21 which conforms to the shape of the roof 4 and is fastened by means of brackets 21a to the roof 12 of the container lltl. The outer rim 22 of the baffle plate 21 lies extremely close to 0.3 the roof 4 of the drum but does not touch it. The purpose of the bafile plate will be explained below.

In FIGURE 1 the charge of the machine is shown to be in that position which it assumes after the washing drum 1 has been filled up. When the drum 1 is rotated by means of the motor 9 an increasing centrifugal force is exercised on the material to be washed as the rate of rotation becomes greater. This tends to move the material in an outward radial direction. The conically ascending floor 3 of the drum 1 has the effect of an inclined plane during this process. The splitting up of the horizontally exective centrifugal force into two components is made clear in FIGURE 4, in which the centrifugal force is Z, the component of this force taking elfect in a direction parallel to the inclined plane 3 is V, and the component taking effect in a direction normal to the surface 3 is P. :The force P presses the charge against the floor 3, whereas force V moves the charge up the floor 3, the articles lying furthest away from the center being displaced with the largest force. This is indicated in FIG- URE 2. The magnitude of the force Z depends on the speed of rotation and the magnitude of both its components P and V depend in addition on the angle of inclination of the floor 3. When the speed of rotation of the drum is decreased the charge slides downwards once more and becarnes slack at the same time.

When the rotational speed is increased the washing liquid is subjected at the same time to a radial, outwardly directed pressure which grows in magnitude, and which forces it through the material to be washed, through the perforations of the drum and into the gap towards the top, corresponding to the direction indicated in FIGURE 2 by the arrow 18. The washing liquid arrives, therefore, at the gap 19, between the roof of the container 12 and the bailie plate '21, and flows via this (as shown by the arrow Ed in FIGURE 2) through the charging aperture back into the drum 1. Without the presence of the bafiie plate 241 the rotating drum roof 4 would tend to project the liquid in the gap 19 outwards, thereby impeding the flowbacl; of the liquid through the opening 5.

In FIGURE 3 there is an illustration of how the material to be Washed climbs up into the top of the drum above a line 23 Where the diameter of the drum is greatest, when the rotational speed of the drum is increased during the spin-drying process. When the valve 16 is opened, the Washing liquid expelled from the drum and from the material to be washed can flow off via the channel 17.

The washing machine illustrated in FIGURES 13 can, by way of example, be run as shown in FIGURE 5. In the graph shown here, time t is plotted as the abscissa, and the speed of rotation n of the drum is plotted as the ordinate n. Within the time t the rotational speed of the drum increases to the maximum rotational speed for the washing process n This speed is afterwards maintained for the time t At this point the motor is slowed down or switched off and the washing drum comes to rest after a time i Now the direction of rotation of the drum is reversed, so that the process which has taken place during times t, to 1 can be repeated but in the opposite direction of rotation. The broken line in FIGURE 5 in the time internal 22, indicates this. This variation in the direction of rotation is repeated throughout the whole duration t of the washing process. As a result of the reversal of the rotation of the drum, tight knotting up of the material to be washed is avoided. This is also the case with washing machines which have a horizontally arranged drum and which can work in reverse, except that in such machines the variations in the direction of rotation occur in a more irregular fashion.

In order that the machine may be switched over to the spin-drying operation, the washing machine is accelerated to the speed 11 necessary for spin-drying, this speed being maintained for a time t This increase in the speed of rotation can be obtained by means of a motor with a variable-speed transmission or, preferably, with a polechangeable motor having interdependent coils and a ratio of the number of pole pairs amounting to 1:3 at least.

The washing drum may of course have some shape other than that indicated. The angle of inclination of the floor of the drum can also be different. If the conical drum floor, for example, ascends more abruptly in an outward direction, it is possible to allow the charge which has ascended to slide down again and become slack without stopping the drum again at any stage. The drum drive can also be obtained by means of a V-belt or a toothed reduction gear. Moreover it is not absolutely necessary for the drum to be reversible. Further, as is already common practice, it is possible to admit fresh water to the machine either constantly or at measured intervals whilst the washing process is going on, the dirty liquid being expelled. Finally the machine can be controlled either semi-automatically or fully automatically by a program control.

I claim:

1. In a washing machine, in combination, a clothes receptacle rotatable about a generally upright axis, said receptacle having a floor sloping conically upwardly and outwardly from said axis at a substantial angle of in:

clination to the horizontal, and driving means for rotating said receptacle at varying speeds duringa washing operation whereby a charge contained in said rcceptacle is displaced upwardly along said floor by a centrifugal force due to higher speeds and slides down therealong upon a reduction of said force at lower speeds, said fioor being formed with corrugations extending generally transversely to the direction of displacement of said charge therealong.

2. In a washing machine having a washing period and an extracting period, in combination, a perforated clothes receptacle rotatable about a generally upright axis, said receptacle having a corrugated floor sloping conically upwardly and outwardly from said axis at a substantial angle of inclination to the horizontal, and driving means for rotating said receptacle at periodically varying speeds during said washing period whereby a charge contained in said receptacle is displaced upwardly along said floor by a centrifugal force due to higher speeds and slides down therealong upon a reduction of said force at lower speeds, said floor being formed with corrugations extending generally transversely to the direction of displacement of said charge therealong, said driving means being constructed and arranged to rotate said receptacle at a speed greater than said higher speeds during said extracting period.

3. In a wshing machine, in combination, a housing, an open-top clothes receptacle rotatable in said housing about a generally upright axis, said receptacle having an upwardly diverging conical floor sloping at a substantial angle to the horizontal while being centered on said axis and provided with inwardly projecting axially spaced annular corrugations centered on said axis and adapted to rub against a charge in said receptacle as the charge is displaced along said floor, and driving means for rotating said receptacle at periodically varying speeds during a washing operation whereby the charge contained in said receptacle is displaced upwardly along said floor by a centrifugal force due to higher speeds and slides down therealong upon a reduction of said force at lower speeds.

4. In a washing machine, in combination, a housing, an open-top clothes receptacle rotatable in said housing about a generally upright axis, said receptacle having an upwardly diverging conical floor centered on said axis at a substantial angle of inclination to the horizontal and provided with inwardly projecting axially spaced annular corrugations centered on said axis and adapted to rub against a charge in said receptacle as the latter is displaced along said floor, inlet means for introducing an initial quantity of a washing liquid into said receptacle, said housing being formed with wall portions paralleling the outer wall portions of said receptacle and forming an annular space therebetween, said floor being provided with a passage connecting the interior of said receptacle with said annular space, and driving means for rotating said receptacle at alternately higher and lower speeds during a washing operation whereby a charge contained in said receptacle is displaced upwardly along said floor by a centrifugal force due to higher speeds and slides down therealong upon a reduction of said force at lower speeds, said washing liquid being centrifugally dischargeabie from said receptacle through said passage into said space and returning from said space to said receptacle through the open top thereof.

5. In a washing machine, in combination, a housing. an open-top clothes receptacle rotatable in said housing about a generally upright axis, said receptacle having an upwardly diverging conical floor centered on said axis at a substantial angle of inclination to the horizontal and provided with inwardly projecting axially spaced annular corrugations centered on said axis and adapted to rub against a charge in said receptacle as the latter is displaced along said floor, inlet means for introducing an initial quantity of a washing liquid into said receptacle, said housing being formed with wall portions paralleling the outer wall portions of said receptacle and forming an annular space therebetween in communication with the open top of said receptacle, said floor being provided with numerous perforations connecting the interior of said receptacle with said annular space, and driving means for rotating said receptacle at alternately higher and lower speeds during a washing operation whereby a charge contained in said receptacle is displaced upwardly along said floor by a centrifugal force due to higher speeds and slides down therealong upon a reduction of said force at lower speeds, said washing liquid being centrifugally dischargeable from said receptacle through perforations into said space and returning from said space to said receptacle through the open top thereof.

6. The combination according to claim 5 wherein said receptacle is formed with a cover plate extending transversely to said axis and provided with a central opening constituting the open top of said receptacle, said housing being formed with stationary bafile means surrounding said opening and closely overlying said roof for conducting wash liquid from said space to said opening.

7. The combination according to claim 5 wherein said receptacle further has a perforated cylindrical portion merging into said conical floor at the widest diameter of the latter.

8. The combination according to claim 7 wherein the height of said conical floor is at least equal to that of said cylindrical portion.

9. The combination according to claim 5 wherein said driving means is reversible.

References Cited in the file of this patent UNITED STATES PATENTS 1,345,761 Fulton July 6, 1920 1,376,227 Rabezzana Apr. 26, 1921 1,390,678 De Laney Sept. 13, 1921 1,629,761 Woodrow May 24, 1927 1,825,651 Barrett Oct. 6, 1931 2,289,162 Anionsen July 7, 1942 2,292,815 Bariffi Aug .11, 1942 2,506,882 Lipscomb May 9, 1950 FOREIGN PATENTS 198,951 Switzerland Oct. 1, 1938

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