US3494471A - Balancing systems for centrifuging machines - Google Patents

Description

United States Patent Office 3,494,471 Patented Feb. 10, 1970 3,494,471 BALANCING SYSTEMS FOR CENTRIFUGING MACHINES Antonio R. Grippo, 5427 Santa Tome St., Buenos Aires, Argentina Continuation-impart of application Ser. No. 430,119,

Feb. 3, 1965. This application May 20, 1968, Ser.

Int. Cl. B01d 33/06 US. Cl. 210-463 5 Claims ABSTRACT OF THE DISCLOSURE A balancing ring system for rotatable receptacles, such as the rotary basket of a centrifugal clothes-drying machine, comprising a plurality of stacked fiexible annular chambers against the inner wall of said basket, and a liquid partially filling these chambers, the said chambers being adapted to be deformed by clothes or the like whereby the liquid there will be circumferentially displaced to balance the distribution of weight in said basket.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of US. application Ser. No. 430,119 filed Feb. 3, 1965, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a balancing ring system for rotatable receptacles such as for example a centrifugal action clothes-drying machine.

Although reference is made to clothes-drying machines, it is to be expressly understood that the present invention is also applicable to any other centrifugal action machines which require a dynamic balancing of the centrifuging component.

Description of the prior art Centrifugal clothes-drying machines generally comprise a rotatable tub or basket driven by a mechanism which comprises an electric motor to which the basket is connected through a vertical shaft transmitting thereto the axial rotary motion for centrifuging the clothes to be treated, said basket having a plurality of perforations for discharging the water saturating the clothes during the centrifuging operation.

In machines of the aforesaid type, the vibrations imparted to the basket during the centrifuging process and particularly at the start thereof, due to an unbalanced distribution of the clothes in the basket, frequently create a series problem. This problem is present even when the clothes are properly distributed in the spinning basket, the vibrations causing jerks transmitted to the basket at the time of starting the centrifugation, with a resulting multiplication of the vibrations imparted to the driving shaft, to the extent that in most cases it has been found necessary to limit the speed of rotation to about 600 rpm. in order to avoid damage to the machine.

It is well known that the higher the rotary speed of the basket, the more effective and accelerated will be the clothes-drying process. This explains the need of an arrangement which will make it possible to raise the speed of rotation considerably. The improvements provided by the present invention make it possible to obtain normal operation of a machine with a 25 to 30 cm. radius basket rotating at a speed of about 1500 r.p.m. with a resulting higher degree of drying of the drying process.

Various devices and arrangements have been proposed in the past in order to solve the same or similar problems although none of the known devices have been successful in offering a simple efiicient solution. Much to the contrary the known devices and arrangements for example contain movable counterbalancing components which are displaced by centrifugal forces acting thereon as a result of unbalanced loads. These known devices have many drawbacks two of which are that the unbalanced load does not act directly against the movable components in order to produce their displacement, and that these components are of rather large size and therefore the finite variations in balancing effect introduced by their change in position does not entirely agree with the infinite variations of the unbalancing force.

A further type of known device incorporates the use of thyxotropic substances housed in an annular ring surrounding the outside of a centrifuging drum. By not enabling the unbalanced load, such as a bundle of clothes, to act directly thereagainst, the compensating effect of this arrangement is indirect and accordingly subject to error; what is more these thyxotropic substances only become effective after certain speeds have been reached so that on starting, they provide no balancing effect.

Devices somewhat more smilar to those of the present invention have been provided, these devices including an annular body of for example water surrounding the centrifuging drum. This type of device more truly balances any eccentricity of the load although they do not avoid the basket from suffering an angular displacement in a vertical plane which is still a drawback sufliciently important to keep manufacturers from offering a clothesdrying machine capable of operating at the mentioned speeds and under the conditions given. This last drawback has been recognized in the art and accordingly an apparatus for achieving synchronized dynamic balance and overcoming such a drawback has been provided. This apparatus comprises flexible receivers for example for water, between a container and a casing, wherein both said container and said casing are movable. This type of device overcomes the problem of vertical angular displacement although its construction is extremely costly its assembly most difficult and what is more it does not act directly in response to the unbalanced load, inasmuch as the mentioned receivers are positioned outside the container. In other words, this type of device incorporates a balancing means external to the container or basket and which must be incorporated into the centrifugal drier during manufacture, it not being possible to incorporate this known type of balancer into a conventional machine, without carrying out a substantial modification.

A further drawback of this type of device is that soapy water becomes entrapped between the container and the casing. This soapy water decomposes quite quickly and gives off a bothersome smell and what is more does much harm to the components in contact therewith.

A still further drawback of this type of device is that the drive force exerted on the clothes basket is transmitted thereto through the mentioned balancing means and accordingly these must be made sufficiently strong to withstand such a stress, obviously this necessary strength is a feature which reduces the balancing effect inasmuch as a truer balance will obviously be obtained if a very flexible material is used. All these known devices incorporating a body of liquid around the rotary basket are provided with a rigid wall for transmitting the force exerted by the unbalanced clothes to this liquid. This feature introduces a further drawback in addition to those already mentioned for this type of device. This new drawback resides in that the liquid displacement produced for balancing the load is not located exclusively in that part where the eccentric load is active.

3 SUMMARY OF THE INVENTION The object of the present invention is to provide means for automatically neutralizing any unbalance in the distribution of the clothes, or other load, within the centrifuging basket by direct action of the unbalanced clothes, or other load, on the mentioned means.

In accordance with the illustrated embodiment of the present invention there is provided a centrifugal clothesdrying machine comprising a rotary basket for containing clothes, said rotary basket defining an inner wall face, of a predetermined circumference, means for rotating said basket about a substantially vertical axis, said inner Wall face being substantially parallel to said verticl axis, a plurality of annular flexible members axially stacked one above the other against said inner wall face and resting on each other, said flexible members having an outer circumference substantially coinciding with the circumference of said inner wall face, at least the portion of each one of said flexible members facing the middle of said basket being adapted to yield and deform under pressure directly exerted by clothes within said basket and in contact with the portion of said flexible members facing the middle of said basket, and a liquid charge at least partially filling said chambers for automatically balancing the weight in said basket and minimizing the vibration thereof during rotation of said basket.

BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate the comprehension of the present invention, reference will now be made to various embodiments, by way of example, in relationship to the accompanying drawings, wherein:

FIG. 1 is a schematic vertical section of a conventional centrifugal clothes-drying and washing machine embodying the improvement in accordance with the present invention; and

FIG. 2 is a perspective vie-w, partially in section, of one of the flexible members in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring in the first place to FIG. 1 there is illustrated an outer casing for a conventional centrifugal clothesdrying machine which as is known in the art is generally also a clothes washing machine. The outer casing 10 rests on the floor by means of legs 11 and has defined on its upper wall portion 12 an opening 13 adapted to be closed by means of a lid 14 connected to the upper wall portion 12 by means of a hinge 15.

Within the casing 10 there is mounted an electric motor 16 having an output shaft 17 connected to a shaft coupling 18 in turn connected to a clutch 19. Shaft coupling 18 is connected directly and permanently to the gears of gear box 21 having an output drive shaft 20 for rotating pallets 27. Clutch casing 19' is rigid with gear box casing 21' also rigid with basket 22. In this way two modes of operations are possible; a first one with clutch 19 free and a second with clutch 19 engaged. In the first mode, electric motor 16 will drive pallets 27 independently at basket 22, while in the second mode, basket 22 will be rotated due to its connection to clutch casing 19'. Clutch 19 is of the electromagnetic type, so that when energized coupling 18 is drivingly connected to 19'. In the first mode, the mechanical connection between electric motor 16 and pallets 27 is established through output shaft 17, shaft coupling 18, gear box 21 and drive shaft 20, while in the second mode, motor 16 is connected to basket 22 through output shaft 17, shaft coupling 18, clutch casing 19' and gear box casing 21'. The rigid connection between gear box 21 and basket 22 (which houses drive shaft 20) is rotatably supported in bearing 38 mounted on a plate member 23, secured by means of springs 24 to casing 10. These means for rotating basket 22 are also supported at 25 on the lower wall portion 26 of casing 10.

Basket 22 comprises a bottom wall 28, a lateral wall 29 and an upper bell shaped portion 41 defined by a lateral wall portion and an upper wall portion and an upper wall portion; lateral wall 29 and upper portion 41 are secured to one another for examle by nuts and bolts (not illustrated). At the level of this connection, that is to say at the upper part of the lateral wall 29, perforations such as 30 are provided in order to enable the water contained within basket 22, during centrifugation, to be ejected therefrom.

The upper wall portion of upper bell shaped portion 41 defines an opening 31 through which basket 22 can be loaded with clothes.

Obviously as is well known in the art, it is necessary to provide water in-feed and outlet means as well as sealing means in order to avoid that water come into con tact with the electrical drive means hereinabove referred to.

It is to be understood that the foregoing description with reference to the corresponding illustration is intended to only schematically represent a conventional centrifuging clothes-drying machine, without in any way implying that the present invention can only be used with a theoretical machine such as so far referred to.

Dealing specifically now with the improvement in accordance with the present invention, there are provided within basket 22, a plurality of hollow annular flexible members 32, 32", 32", 32 axially stacked one above the other against the inner wall face 33 of basket 22 and resting one upon the other, this last feature plus the fact that these flexible members have an outer circumference which substantially coincides with the circumference of said inner Wall face 33, thereby providing a tight fit therebetween, enables them to remain in the position illustrated, during all phase of operation. Flexible members 32, 32, 32", 32, 32 are preferably made of rubber although the object of the present invention is also achieved by having these flexible members comprise a rigid outer portion 34 (FIG. 2) and a flexible inner portion 35. Obviously, the flexible portion 35 will face the middle of the basket when flexible members 32, 32', 32", 32", 32 (FIG. 2) are positioned within basket 22.

Although hollow flexible members 32, 32, 32", 32", 32 have been illustrated as being of approximately oval radial section, it is to be understood that the section thereof could be rectangular, square, or any other shape which fulfills the objects to be achieved, and each flexible member defines an annular chamber.

As may be seen from FIG. 2, these flexible members are independent one from the other so that they can be easily incorporated into any conventional centrifugal clothes-drying machine of the type schematically illustrated in FIG. 1 by merely introducing the first one of these annular members 32' and resting it against the bottom wall 28 in the position illustrated in FIG. 1.

Thereafter a second annular member 32" is inserted through openings 13 and 31 and positioned to rest upon the already inserted annular member 32'. This procedure is followed with the remaining annular members which are to be inserted within basket 22. Although in FIG. 1 annular members 32', 32", 32" and 32 have been illustrated as being of the same size, it is possible for them to be of slightly different sizes without this affecting the compensating effect thereof. Furthermore, and although in FIG. 1 the annular members 32, 32", 32" and 32 are not spread over the entire lateral wall 29, it is possible, and in no way a disadvantage, to have them extend entirely from bottom wall 28 to the level of perforations 30, or over the entire upper portion 29.

On outer portion 34 at substantially regular intervals there are adhered spacing strips 36. Each one of these strips may be made of rubber or other suitable material. Fundamentally, the object of these strips is to define channels 37 therebetween through which the water within basket 22 can move freely. As is known in the art, most centrifuging drums such as basket 22 are generally supported exclusively by their lower portion so that when subject to a centrifugal action the upper portion does not only rotate but suffers a circumferential displacement due to the centrifugal force acting on the free upper portion. It is for this reason that the water contained within basket 22 is carried upwards within basket 22 and ejected through perforations 30. In orderto permit this upward movement of water, channels 37 are defined.

In order to obtain the 'counterbalancing effect desired, the chambers defined flexible members 32 are partially filled with a liquid, for example ,water. Obviously, it is desirable that the water contained within flexible members 32 rotate at the same speed as the basket. Due to inertia, upon commencement of rotation of the basket, the water will lag behind for some time until friction makes the entire mass of water rotate at the same speed as the basket. If this time interval is to be reduced, it is desirable to increase the friction between the inner faces of flexible members 32 and the fluid contents thereof, to which effect strips 36 are also suitable. As the outer circumference of the flexible member 32 substantiallly coincides with the circumference of the inner wall face 33, the existance of strips 36 will cause flexible members 32 to rest against inner wall face 33 with a slight outer radial force whereby outer portion 34 will be circumferentially undulated, such undulation defining internal protrusions within flexible members 32 and channels 37 on the outside thereof. Such protrusions serve to increase the friction between the internal faces of the flexible members 32 and the liquid contents of the flexible members.

Although strips 36 serve to increase the friction between flexible members 32 and the liquid contents thereof it is possible to include, within flexible members 32, internal deflectors 39 provided for the same purpose (see cut away portion of FIG. 2 which represents a possible alternative) Generally, these internal deflectors 39 are of flexible material and are secured on a strap 40, only part of which is seen in FIG. 2. During construction. of flexible members 32, and before the annular flexible member is closed by welding both ends, strap 40 with internal deflectors 39 thereon, is inserted within flexible members 32.

In operation any mass of clothes which may become eccentrically positioned will act against one or more of the flexible members 32, depending on the height of the eccentric mass. From this it will already be seen that water displacement is achieved exclusively by direct action of the clothes on the flexible members and that this water displacement will only occur at those points where such as eccentric mass acts.

In this way cause and effect are diametrically opposite and act virtually in the same horizontal plane. It is important to recognize this last fact inasmuch as it is one of the beneficial features of providing a plurality of flexible members 32. Normal house-hold clothes washing and drying machines require at least three flexible members 32-although more are generally provided in order to increase this effectiveness.

A typical height for these flexible members is approximately 2 /2 in., this height has been found to yield excellent results. Obviously larger or smaller members can be used without departing from the spirit of the invention as defined in the appended claims.

The beneficial effects achieved by providing a plurality of flexible members can be explained as follows:

Let us suppose to this end that only one flexible member is provided, of a height equivalent to the sum of the heights of the three flexible members 32', and 32" and 32 illustrated.

Generally the eccentric clothes form an eccentric mass of trapezoidal cross section while the displaced mass of water will be of rectangular cross section whereby the respective centre lines of action of the centrifugal forces are not at the same height (the centre of the trapezoid is not at the same height as the centre of the rectangle). This difference in height causes the basket to be subject to an angular displacement in a vertical plane, thereby producing an eccentricity which most of the devices of the prior art do not compensate.

From the foregoing it can be seen that the inclusion, as per this invention, of a plurality of annular members 32 overcomes the foregoing problem.

It will be evident, to those skilled in the art that if the annular members 32', 32", 32" and 32 are included in a conventional machine, then the drive mechanism thereof can be modified so as to drive the basket at higher speeds compatible with the better balanced basket.

It will be understood that improvements may be introduced into the embodiment described by way of example and modifications may be made in the constructions and material employed without departing from the scope of the invention.

What is claimed is:

1. A balancing ring system for the rotatable receptacle of a machine such as the rotary basket of a centrifugal clothes-drying machine, said rotatable receptacle defining an inner wall face and said machine comprising means to rotate said receptacle about a substantially vertical axis, said inner wall face being subtantially parallel to said vertical axis, the balancing ring system comprising a plurality of hollow flexible members axially stacked one above the other tightly against said inner wall face and resting on each other, each of said members defining an annular chamber, at least the portion of each one of said flexible members facing the middle of said receptacle being constructed to yield and deform under pressure directly exerted by a load within said receptacle and in contact with the portion of said flexible members facing the middle of said receptacle, and liquid partially filling said chambers for automatically balancing the load in said receptacle and minimizing the vibration thereof during rotation of said receptacle.

2. The system of claim 1, wherein each one of said flexible members is provided with internal deflectors.

3. The system of claim 1, wherein a plurality of circumferentially spaced apart upstanding strips are secured to the outer portion of each one of said flexible members, said upstanding strips forming, by deformations, protrusions within said flexible members, when these flexible members are in operative position in said receptacle, said protrusions being of such dimension as to cause increased friction between the internal faces of the flexible members and the liquid contents thereof.

4. The system of claim 1, wherein a plurality of circumferentially spaced apart upstanding strips are secured to the outer portion of each one of said flexible members, said spaced strips causing at least part of the outer portions of said flexible members to be spaced apart from said inner wall surface, thereby defining channels between said strips for circulation of water therethrough when said flexible members are in operative position in said receptacle.

5. The system of claim 1, including circumferentially spaced apart means positioned radially outwardly from the outer portion of each one of said flexible members, said means forming protrusions within said flexible members, when these flexible members are in operative position in said receptacle, said protrusions being of such dimension as to cause increased friction between the internal surfaces of the flexible members and the liquid contents thereof.

(References on following page) References Cited UNITED STATES PATENTS Adams 74573 Johnson 210363 X De Remer 210363 Kirby 210--363 X Cahn 210-363 X Smith 210363 X 8 2,836,301 5/1958 Bruckman 210363 X 2,964,192 12/1960 Brown 210363 3,253,710 5/1966 Engel 210--363 X REUBEN FRIEDMAN, Primary Examiner W. S. BRADBURY, Assistant Examiner US. Cl. X.R. 6823.3; 74573

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