US2471217A - Rotatable device - Google Patents

Description

y 1949. P. A. JOHNSON 2,471,217

ROTATABLE DEVICE Filed July 13, 1945 2 Sheets-Sheet 1 INVENTOR.

P. A. JOHNSON ATTORNEY P. A. JOHNSON ROTATABLE DEVICE May 24, 1949.

2 Sheets-Sheet 2 Filed July 13. 1945 I v I o p I p p INVENTOR. P. A.JOHNSON A T TOR/V5 Y Patented May 24, 1949 ROTATABLE DEVICE Philip A. Johnson, Van Nuys, CaliL, assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application July 13, 1945, Serial No. 604,764 I 3 Claims. (Cl. 74-573) sired and lends itself particularly to use in centrifugal drying devices, such as clothes driers, in which it is impossible or impractical to symmetrically distribute the load about the axis of rotation.

Essentially the invention involves the addition to a rotatable structure of an annular liquid receptacle normally symmetrical with respect to the axis of rotation but automatically responsive to a lack of balance to'distort in such direction as; to concentrate the liquid on the side of the structure opposite the unbalanced weight.

The'manner in which the foregoing object together with other more specificobjects and features of the invention are achieved will be apparent from the detailed description to follow of certain specific embodiments thereof.

In the drawing:

Fig. 1 is a vertical section through a portion of a washing machine incorporating the invention, showing the elements in normal position.

Fig. 2 is a side view similar to Fig. 1 but showing the elements positioned to neutralize an unbalanced load.

Figs. 3, 4, 5 and 6 are vertical sections showing alternative structures in accordance with the invention.

Referring first to Fig. 1, there is shown the upper portion of a washing machine comprising an outer casing ll] containing a tub II. There is positioned within the tub I I a rotatable clothes basket I 2. This clothes basket comprises an outer, open-top container having a cylindrical wall l3 and a flat bottom wall M, which normally rests upon a flange iii of a bushing it, which extends through the bottom wall I! of the tub. A drive shaft l8 extends through the bushagitator I9, the agitator having at its lower end a sleeve bearing 20, which bears against the 'ing it and is connected at its upper end to an basket l2 remains substantially stationary by virtue of the fact that it is out of direct contact with-the agitator and rests on the stationary flange l5 of the'busliing It. When the washing operation is completed, the clothes are dried by elevating the shaft 18. and rotating it continuously in one direction. Elevation of the shaft causes an outwardly extending flange 2| on the agitator I9 to engage against an inwardly extending flange 22, secured to the bottom wall ll of the basket, as by welding 23. The shaft l8 and agitator l9 are elevated sufficiently to lift the bottom wall IA of the basket clear of the flange l5, as shown in Fig. 2.

As so far described, the structure is substantially in accordance with prior devices, which had the objectionable characteristic that unless the clothes were perfectly distributed within thebasket l2 the latter would be unbalanced and would tend to vibrate when rotated.

In accordance with the present invention, unbalance and resultant vibration are prevented by providing the basket I2 with aninner peripheral-wall 24, which is radially movable with respect to the wall l3, but is, sealed with respect to the latter at the top and at the bottom to provide an annular chamber 25 adapted to confine a body of water or other balancing liquid. As

shown in Fig. 1, the lower edge of the inner wall 24 is connected to the bottom wall It by an annular connectingwall 26 of rubber, and the upper edge ofthe inner wall 24 is connected to the upper edge of the wall I 3 by an annular wall 21 of rubber. The lower edge of the inner wall 24 is preferably ,turned in to form a fiat lip 28 adapted to rest upon the rubber wall 26. The inner edge of the rubber wall 26 is sealed to the bottom wall I 4 by clamping it between the bot-..

tom wall and the outer edge of the flange member '22. The outer edge of the rubber wall 28 is sealed to the wall 24 by a clamping ring 29 riveted to the Wall 24. The rubber wall 21 is likewise sealed to the upper edges of the walls 24 and I3 by riveted clamping ring 30 and 3i respectively.

The space 25 is completely filled with water or other balancing liquid, and, when the basket is spinning, the inner wall 24 is shifted by the centrifugal force of an unbalanced load, to concentrate the water on the side of the axis opposite to the center of gravity of the load. Thus, as shown in Fig. 2', a load of clothes 32 within the basket is shown unevenly distributed, with the clothes concentrated in the left side of the basket as it appears in the drawing. During rotation, the centrifugal force developed in the clothes is therefore unbalanced, and causes the inner.-.-wall member 24 to shift, with respect to the outer wall i3,.to the left as shown in Fig. 2.

This brings the inner wall 24 closer to the outer wall I: at the point where the clothes are massed. and causes the walls 24 and I: to separate at the diametrically opposite point. Water in the space 25 is therefore displaced from the point adjacent the greater mass-of clothes to the diametrically opposite point, as clearly shown in Fig. 2.

It is found in practice that the inner wall 24 moves just sumciently to effect a shift in the distribution of the water in the space 25 necessary to compensate for the unbalance of the clothes load. If the unbalance of the clothes load is very slight, only a slight corrective movement of the inner wall occurs, whereas, if the unbalanc'e resulting from the equal distribution of the clothes is large, the corrective movement of the inner wall 24 is correspondingly greater.

The movement of the inner wall 24 out of concentric relation is limited, because any portion of the wall 24 that is closer to the wall I3 than another portion of the wall 24 is exposed to a greater water pressure. Thus, the pressure developed in the water 24, due to centrifugal force, increases as the wall I3 is approached, the same as the pressure increases with depth in a stationary body of water. Furthermore, at the speeds of rotation ordinarily employed in devices of this type, the centrifugal forces developed in the water 25 are much greater than the force of gravity, so that the pressure increases relatively rapidly as the wall I 3 is approached. Therefore, relatively small movement of the wall 24 out Of concentric relation to the outer wall materially reduces the pressure acting on that portion of the wall closest to the axis of rotation and increases the water pressure acting against the diametrically opposite portion of the wall.

During normal operation, the basket is accelerated slowly during the spinning operation, and the inner wall 24 shifts gradually into its ultimate position as the centrifugal forces resulting from rotation increase. However, the structure is capable of reacting quickly to an unbalanced condition. Thus it is found that if the basket is brought up to speed while empty, and a mass of clothes is then thrown into the basket while it is rotating, the wall 24 is moved immediately into a new position sufficient to compensate for the unbalanced clothes load, and even momentaiy vibration of the device is substantially prevented.

As shown in Fig. 1, the inner wall 24 is tapered from small diameter "at the bottom to a larger diameter at the top, and water extracted from the clothes by the spinning action is directed upwardly along the wall 24 and over the top thereof by the centrifugal force. The water then impinges against the wall ll of the tub and runs to the bottom where it may be drained off through a suitable drain cock 33.

The schematic diagram of Fig. 3 shows a modific'ation of the structure of Fig. 1, in which the space 25a containing the balancing liquid is defined by an annular flexible container 35 of rubber or the like, which fits between the inner wall 24a and the outer wall |3a of the basket. This construction eliminates the sealing walls 25 and 21 of Fig. 1. The device operates in the same general manner as that of Fig. 1.

An important advantage of my structure is that it instantly responds to any change in the unbalance in either direction. Thus in the case of a clothes centrifuge the unbalanced load becomes progressively less as the water is extracted,

and the inner wall 24 gradually moves back toward concentric relation with the wall H, to maintain the proper distribution of the balancing liquidto lust balance the clothes load at all times.

Fig. 4 shows schematically another arrangement whereby the invention may be employed without the use of sealing walls, in a device from which liquid does not have to be drained. Thus in this instance there is provided an outer rotatable container 40 having a cylindrical outer wall 4|, a fiat bottom wall 42, and an annular flat top wall 43 extending inwardly from the cylindrical wall 4|. There is contained within the outer container 40, an inner container 44 having a cylindrical wall 45, and flat annular bottom and top walls 46 and 41, respectively. The bottom wall 42 of the outer container 40 is secured to and rotated by a drive shaft 48, supported in a bearing 49. (The inner container 44 rests in sliding relation on the bottom wall 42 of the outer container.)

The annular space between the cylindrical walls 45 and 4| and between the bottom walls 46 and 42 contains a liquid, such as water, in amount such as to completely fill the space between the cylindrical walls 45 and 4| when the device is rotating, as shown in Fig. 4. However, the amount is not great enough to cause it to leak out between the walls 41 and 43. If it is not loaded, or if there is a balanced load within the container 44, the latter will remain coaxial with the outer container 40. On the other hand, if there is an unbalanced load in the container 44, the latter will shift laterally to displace water to a diametrically opposite point and restore the balance, the same as in the arrangement of Fig. 1.

It is to be understood that the invention is not limited to use as a centrifuge. Thus, in the arrangement of Fig. 4, forexample, the container 44 might just as well be a solid body, and the structure can be used as a flywheel or gyroscope which will be self-balancing at high speeds and thereby eliminate need of extremely accurate machining and balancing during manufacture.

Two variations of the structure previously described are disclosed in Figs. 5 and 6. In the previously described modifications, the inner rotating member moved bodily to compensate for unbalance. In the modification of Figs. 5 and 6 the rotating basket is pivotally supported near the top so as to swing at the bottom and displace the balancing liquid.

Referring first to Fig. 5, there is shown a rotatable basket 55 having tapered inner and outer walls 56 and 51, interconnected by a bottom wall 58 to define an annular trough in which material to be centrifuged is placed. The basket is supported for rotation by a shaft 59, the shaft being supported in a stationary bearing 50. The upper end of the shaft 59 is connected to the basket 55, adjacent the upper end of the inner wall 56, for limited rocking motion, as by a bushing 6| of rubber or the like.

For balancing purposes, there is aflixed to the shaft 59, below the container 55, a dish-shaped receptacle 62 having an in-turned upper wall 63 which defines an annular trough 64 into which an annular displacement member 65 projects. The displacement member 65 is fixed to the bottom wall 58 of the basket 55.. A quantity of liquid 65 is maintained in the receptacle 62, the liquid lying in the bottom, as shown in Fig. 5.

when the device is at rest. When the device is rotating, the liquid 66 is thrown out into the annular trough 64 by centrifugal force, and is evenly distributed so long as the basket 55 is empty or. contains a balan'cedload. However, if the container 55 contains an unbalanced load, the latter developes a centrifugal force which rocks the basket about the bearing 6|, causing the displacement member 65 to displace liquid from the trough 64 on the side adjacent the greatest load, the displaced liquid flowing to the opposite side of the trough until the centrifugal force of the unbalanced liquid develops a moment about the bearing 6| equal and opposite to the moment developed by the unbalance load in the basket 55.

The structure shown in Fig. 6 differs from that shown in Fig. 5 only in that its balancing liquid is confined in an annular flexible tube. The corresponding elements in Fig. 6 bear the same reference numerals as shown in Fig. 5, with the sufflx a. It will be observed that the balancing liquid 66a is contained within a rubber tube 61 which is positioned between the reentrant wall 63a of the receptacle 62a and the displacement member 65a that is secured to the basket 55a. The operation of the arrangement shown in Fig. 6 is identical with that of the arrangement shown in Fig. 5, except that the balancing liquid All of the modifications shown have the advantage of simplicity and ruggedness, in addition to the advantage of adequately compensating for relatively large unbalanced loads.

Although for the purpose of explaining the invention, certain specific forms of apparatus incorporating it have been described in detail, the invention is broadly applicable to many other specific forms of apparatus and it is therefore to be limited only to the extent set forth in the appended claims.

I claim:

1. A device of the type described comprising: a rotatable body and means supporting it for rotation about a predetermined axis and for swinging movement about a center located in said axis; an axially symmetrical receptacle concentric with respect to said predetermined axis and axially displaced from said center and rotatable with said body, said receptacle comprising an annular channel open on its inner side and adapted to retain a ring of liquid by centrifugal force during rotation; and an annular member secured to said body and extending into said annular channel during rotation of said device.

2. A device as described in claim 1 including a closed flexible annular tubular container in which said liquid is contained, said tubular container being supported in said annular channel and being contacted by said annular member secured to said body.

3. A device of the type described comprising: an outer member rotatable about an axis and having a peripheral wall symmetrical about said axis; means for rotating said outer member; an inner member having a peripheral Wall positioned' within the peripheral wall of said outer member, said inner member being supported within said outer member for lateral movement with respect thereto; a first flexible annular wall interconnecting the lower edges of said inner and outer peripheral walls; a second flexible annular wall interconnecting the upper edges of said inner and outer peripheral walls; said flexible annular walls cooperating with said peripheral walls to define therebetween an annular chamber for retaining a liquid between said peripheral walls during rotation of said device, whereby the pressures developed in said liquid by centrifugal force react on said inner wall, and the lateral movement of said inner wall out of concentric relation to said outer wall displaces liquid from the region where the walls are closest to the region where they are farthest apart.

PHILIP A. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

Hvid Mar. 9, 1943

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