Abstract:
The specification discloses a dispenser for liquid additives for use in an automatic clothes washer, particularly of the type having an upright agitator with hollow tubular internal portions. The dispenser structure is adapted to be mounted wholly within the hollow agitator interior, and comprises two separate but interconnected stages which are coordinated to complete dispensing operation only after predetermined amounts of agitator rotation at or above a predetermined spin velocity. The first stage of the dispenser apparatus is preferably of the centrifugal type, including a rotating cup which expels the liquid additive by the effects of centrifugal force, and the second stage, which receives the liquid expelled from the first stage, is preferably a siphon device arranged so that it can only be primed and actuated when a full charge of additive has been received from the first stage. The top of the siphon tube in the second stage is preferably disposed near the center of a rotatable cup, whereby siphon operation is also dependent upon and related to agitator rotational speed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to automatic washers and means for dispensing liquid inside automatic washers at designated points during their programmed cycles of operation. More particularly still, the invention relates to means for dispensing liquid wash additives, e.g., fabric softeners or blueing, in automatic washers particularly those of the type which utilize intermittent or progressively staged acceleration of the agitator during spin cycles, and especially to dispensing means for such applications which provide for automatic dispensing operation at a desired point following the attainment of a predetermined spin velocity for a predetermined time over a course of both acceleration and deceleration. 
     2. Prior Developments and Previous Practices 
     A number of different types of dispensers for liquids in automated washing devices have been used heretofore, among which are such differing approaches as electromechanical devices which require programmed remote actuation, as well as a number of what are essentially self-actuated devices of a primarily mechanical nature which respond to various conditions during the operation of the washing machine, often a predetermined agitator speed threshold, to dispense liquids at some given point during the washing process without the need for external control devices. 
     Centrifugally actuated dispensers are frequently encountered in the latter group, and a good example of such a device is that shown in U.S. Pat. No. 4,656,844, which is commonly owned herewith and which is hereby incorporated by reference. As discussed in that patent, centrifugal dispensers typically employ a cup-like or other such receptacle which is usually either mounted upon the agitator or secured to the basket of the washing machine, such that liquid additive contained within the receptacle is forced upward and outward along the receptacle walls as the rotational speed of the agitator or basket increases, typically during a spin cycle, until the point is reached where the additive escapes over the edge of the receptacle. When the basket slows down, the fluid works its way to the wash basket to contact the wash load. 
     Various other forms of centrifugal liquid dispensers have also been proposed, as have various other types of devices based upon other and different physical principles, e.g., siphons, etc. Often, such other types of liquid dispensers are also related to or dependent upon agitator spin speed, as is true for example of the devices shown in U.S. Pat. Nos. 3,057,181 and 4,154,069, the first of which utilizes centrifugal force produced by the spinning agitator to load o prime the siphon tube while the latter uses an impact tube coupled to the agitator so that motion of the latter moves the impact tube through the liquid additive to be dispensed and causes the liquid to enter the impact tube and then move onward into the siphon. Many other particular approaches have been proposed, including the use of float-actuated dispensers, such as that shown in U.S. Pat. No. 3,724,242. 
     In order to achieve delayed dispensing at some later point during the washer operation, some dispensers have been proposed which utilize a pair or more of ganged or cascaded release stages. Thus, for example, U.S. Pat. No. 3,620,054 discloses a two-part centrifugal liquid dispenser which includes an inner-cup portion as well as an outer-cup or other such housing. Another different such type of device is shown in U.S. Pat. No. 4,691,538, which shows a staged pair of centrifugal dispenser sections disposed one above the other along the agitator axis. Somewhat similarly, the aforementioned U.S. Pat. No. 3,724,242 includes, with the float-actuated dispenser section already noted, a first centrifugally-operated dispenser section which discharges into the float-actuated dispenser section. To some extent, the aforementioned U.S. Pat. No. 4,154,069 might be considered a two-stage device, since the described impact tube structure which in effect loads the siphon could perhaps be considered a first stage and the siphon considered a second stage; indeed, this patent refers to the impact tube stage stage as a &#34;timing means&#34;. 
     Notwithstanding the relatively extensive prior development of liquid-dispensing apparatus for automated washing machines, the continuing development of new and improved such machines brings about new circumstances and conditions which prior developments do not address and for which they do not provide solutions. In addition, continuing refinement of washer operation and sequences, together with advances and changes in detergents and additives, including for example fabric softeners, result in the apprehension of new and/or changed perceptions of the optimum time and conditions for dispensing wash additives. 
     Accordingly, many present-day automatic washers utilize selected and varying, non-constant agitator spin speeds, including &#34;sub-interval&#34; spin cycles. Furthermore, many such present-day washers utilize pulse actuation (energization) of the agitator drive motor. For example, reference is made to commonly-owned U.S. Pat. No. 4,779,431, which discloses and depicts particular details and aspects of such actuation, in accordance with which the agitator drive motor is energized by a series of electrical pulses whose duration and/or repetition rate is selected to gradually bring the agitator up to a desired spin speed over a period of time. With this type of actuation, the agitator actually undergoes an alternating sequence of positive and negative acceleration (i.e., deceleration), such that the resultant velocity profile comprises an alternating sequence along an increasing slope until the desired ultimate speed level is finally reached. As will be readily understood upon contemplation, such a velocity profile has an immediate and profound effect on centrifugally-actuated additive release mechanisms and may well result in their malfunction. 
     Accordingly, the need exists for a liquid additive dispenser for automatic washers which is readily adapted to washers with non-constant spin speeds and which, in addition, are preferably of a primarily or exclusively mechanical nature, which are self-actuating, and which have no moving parts which may produce undesired performance variations as well as malfunction and, ultimately, early failure. Furthermore, a need exists for a liquid wash additive dispenser which will operate to dispense the additive at a specific time near the end of the wash cycle, following certain increases and decreases in agitator speed, such that an optimum quantity of the additive (e.g., fabric softener) will remain in the wash load for optimal benefit during the subsequent drying cycle. 
     SUMMARY OF THE INVENTION 
     The present invention has for its major objectives and advantages the provision of a new type of liquid additive dispenser which effectively satisfies all of the aforementioned present-day needs and which is, as desired, without moving parts and does not require any external actuation, such as by connection to the washer control system. The novel dispenser in accordance herewith is entirely self-contained and is actuated solely by the progressive performance of the automated wash cycle programmed into the washer, to dispense additives after the spin cycle and following various increases and decreases in agitator speed, whereby dispensing takes place at a particular desired time near the end of the wash cycle, whereby an optimum quantity of the additive (e.g., fabric softener) remains in the wash load during the subsequent drying cycle to provide its maximum benefit from the additive. 
     Furthermore, the novel dispenser system disclosed herein function in accordance with a new and advantageous operational concept, by which the system is self-activating as a function of multiple conditions which are in effect integrated to reach the point of actuation, i.e., agitator speed in excess of a minimum over a cummulative length of time which may comprise several different sequences occurring at different points in time. 
     More particularly, the dispenser in accordance herewith comprises an assembly which is located wholly within the washer agitator, and which includes a pair of different dispensers which are axially staged for successive and interrelated operation. More particularly still, the dispenser in accordance herewith preferably comprises a first centrifugally operated dispensing stage coupled to a second siphon-operated stage, whereby additive dispensing into the wash does not occur until a predetermined sequence of washer operation has taken place and a particular point during the wash cycle has been reached. Thus, the dispenser is relatively uncomplicated mechanically, is entirely mechanical in nature, has no moving parts, is self-actuating, is directly and easily accessible during the operation of the washer, and furthermore, is of a nature providing a self-cleaning function, which occurs during subsequent parts of the wash cycle. The novel dispenser in accordance herewith is thus of very high reliability while at the same time providing significant cost advantages in manufacture and assembly. 
     The foregoing attributes, objectives, and advantages of the invention will become more apparent following consideration of the ensuing specification and drawings which set forth a preferred embodiment thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a frontal perspective view of an automatic washing machine of the type in which the invention may be advantageously utilized, with portions in cutaway to reveal certain internal components; 
     FIG. 2 is an enlarged fragmentary central sectional elevation of the washer shown in FIG. 1, generally showing an agitator embodying a dispenser in accordance herewith, together with agitator drive means; 
     FIG. 3 is a further enlarged sectional elevation of the agitator and dispenser shown in FIG. 2, showing details thereof; 
     FIG. 4 is an exploded perspective view showing the dispenser structure; 
     FIG. 5 is a graphical representation in the form of a timing chart showing illustrative pulse-form motor excitation; 
     FIG. 6 is a graphical representation coordinated to FIG. 5 and showing an illustrative agitator velocity profile based upon motor excitation in accordance with FIG. 5; and 
     FIGS. 7-13 are a series of simplified, fragmentary sectional views of the agitator and dispenser as shown in FIG. 3, together constituting a schematic representation of dispenser operation during the washing sequence. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now in more detail to the drawings, a preferred form of the additive dispenser in accordance with the invention is intended for utilization in an automatic washer such as that shown generally in FIG. 1 and designated there by the numeral 10. As so depicted, the washer 10 is generally of a known type and includes a generally rectangular cabinet 12, having sides 14, 16, etc., for housing the operational parts of the machine, together with a hinged top 18 through which the user may load and unload articles to be washed, as well as adding washing substances, including fabric softeners and other such additives. On the top of the cabinet 12, at the rear, is a control console 20 which contains the operating controls for the washer, represented by actuation knobs 22 and 24, generally of a familiar nature and including cycle and wash-type selectors, etc. 
     Housed within the cabinet 12 are such familiar major subassemblies or units as a wash tub 26, a basket 28 (which is usually perforate in nature), and an agitator 30. In the bottom of the cabinet are housed the drive motor 32, and some form of desired transmission 34, by which the agitator 30, and typically the basket 28 as well, are coupled to the motor 32, for rotation thereby. As will be understood, the tub 26, wash basket 28, and agitator structure 30 are concentrically mounted along a common central axis, and the basket and agitator are typically mounted for separate drive motion from the motor and transmission 32, 34, so that they may be selectively rotated either oppositely or in unison to accomplish the desired wash cycle performance. 
     The agitator structure 30, shown generally in FIG. 1, is illustrated in more detail in FIGS. 2 and 3, where it will be seen to include a plurality of spaced, vertically-oriented vanes 36 for moving a load of wash placed in the basket 28, so as to accomplish the desired washing action. As further shown, the vanes 36 flare outwardly at their bottom extremities 38 to better accomplish this purpose, and have their lowermost edges in closely spaced relation to an angularly flared, generally annular apron or plate 41, which is concentrically disposed with respect to the remainder of the agitator structure along the rotational drive axis 42. The underside of apron 41 is disposed directly adjacent the lower extremity 44 (see FIG. 2) of the wash basket 28, sloping outwardly and downwardly toward the cylindrical sides of the latter, all in a known manner. 
     As further illustrated in FIGS. 2 and 3, the interior of the agitator 30 essentially defines a hollow tube 46, which contains a centrally-disposed mounting hub 48 near its lowermost extremity that has a splined interior 50 for receiving a complementary spline on the upper extremity 52 of the agitator drive shaft 54, all in a generally known manner. Further, the additive dispenser 60 in accordance with the invention is, in the preferred embodiment, carried on and in the hollow uppermost extremity of the agitator 30. 
     More particularly, the dispenser 60 basically comprises a pair of coaxially disposed cup-like additive receptacles 62 and 64 (FIGS. 3 and 4) which are partially telescoped with one another and with the top of the agitator tube 46, as illustrated. The lower such receptacle 64 is nested directly within the hollow upper extremity of the agitator interior 46, and the upper receptacle 62 is disposed coaxially within receptacle 64, with the bottom extremity of upper receptacle 62 spaced above that of receptacle 64 to provide an intervening compartment 40 comprising a second stage of the dispenser apparatus, as explained more fully below. The upper extremities of receptacles 62 and 64 are interconnected by a toroidally shaped collar 70 whose inner periphery defines an inlet pouring spout 72, in which a strainer basket 74 is preferably mounted to prevent entry of undesired foreign objects while at the same time allowing liquids to pass readily through into the interior of dispenser 62. A plurality of mutually spaced, annularly-arranged inner spacers 76 is preferably disposed between the upper extremity of receptacle 62 and the outer periphery of the collar 70, whose lower annular extremity 78 is spin welded to the top of the receptacle 64. The uppermost extremity of receptacle 64 preferably fits snugly inside the upper extremity of the agitator tube, and is seated therein by an annular ring 79. 
     The aforementioned intervening compartment 40 comprises a second stage of the dispenser in accordance herewith, and houses a siphon tube 82, such second stage preferably being a siphon stage. As illustrated, siphon tube 82 preferably has a first opening or end extremity 84 positioned radially outward from rotational axis 42 and a second opening or end 86 which is disposed substantially along the axis 42 and within a downwardly-extending discharge tube 88 that supports a lint filter 92. 
     The first opening or end 84 of siphon tube 82 is preferably disposed within a shallow, downwardly dished concavity 94 formed in the bottom of the second receptacle 64. Opening 84 comprises the siphon inlet, and is disposed above the second opening 86, which comprises the siphon outlet. Siphon tube 82 defines an upstanding loop or reverse bend 96 which extends between and above the two openings 84 and 86. Preferably, the arcuate upper extremity of bend 96 is formed within a corrugated section of the tube (as shown in FIG. 3), by which the latter may be readily bent into the smooth inverted U-shape shown without cross-sectional deformation. The bend 96 is preferably received within a toroidally-shaped recess 98 forming the bottom surface of the first receptacle 62, whereby the dispenser structure is integrated and the siphon tube retained steadily in position. The inside bottom surface 100 of receptacle 62 is preferably made smoothly convex. As will be understood, the hollow interior 46 of agitator structure 30 communicates downwardly into the bottom extremity of wash basket 28, mounting hub 48 being somewhat spider-like in nature, or otherwise having downwardly extending passages through it, such that fluid travelling downwardly through the interior of the discharge tube 88 may enter the bottom of the wash basket by passing through the open annular upper extremity of agitator base portion or skirt 41. 
     In a structural sense, the outlet or discharge tube 88 is secured in place to the bottom of the second receptacle 64, for example by spin-welding. The lint filter 92 may be snap-fitted onto the lower extremity of discharge tube 88 and merely positioned within hollow agitator tube 46 upon insertion of the dispenser assembly 64. The lower, outlet portion of siphon tube 82 is preferably firmly seated within a plug seal 102 at the base of second receptacle 64, and the upper bend 96 may be adhesively or otherwise secured in place within the toroidal recess 98 on the underside of the upper additive receptacle 62, whose uppermost extremity may be secured to the inner spacers 76, and, in turn, to the upper collar 70 which comprises the inlet to the dispenser apparatus. 
     As previously indicated, the dispenser apparatus in accordance with the invention is particularly useful in automatic washers having multiple and varied spin cycles, particularly those employing &#34;sub-interval&#34; spin operation and, as a general matter, in washers employing modulated-pulse agitator motor drive excitation, of the general type disclosed and described in U.S. Pat. No. 4,779,431. For convenience, and to facilitate a more rapid understanding of such excitation, FIG. 5 provided herewith illustrates a typical start-up sequence of such pulses, in which an initial pulse 102 of relatively short duration is followed by an intervening off time 104 and then a ensuing pair 106, 108 of longer-duration &#34;on&#34; pulses 106, 108 which are separated from one another by substantially equal spacings 110, 112 that are longer in duration than the aforementioned spacing, or off time, 104. Following pulse 108 and spacing 112, a steady-state &#34;on&#34; pulse 114 of variable duration occurs, whose on time is sufficient to maintain the maximum agitator speed generally constant. 
     FIG. 6, shown in correlated juxtaposed position to FIG. 5, illustrates the velocity profile which results from the modulated-pulse excitation shown in FIG. 5. As thus illustrated, the velocity profile 116, comprising a speed versus time graph, has a series of sawtooth-like velocity increases 118, 120, and 122, followed by a flattened, continuous level 124. These speed changes correspond to and result from application of the drive pulses 102, 106, 108, and 114, respectively. In this manner, the agitator is brought from a condition of standstill, extending from times t 0  and t 1  to final velocity 124 occurring after time t 7 , and slightly before time t 8 , times t 2  -t 6  inclusive corresponding to the trailing edge of excitation pulses 102, 106, and 108, respectively, and time t 7  corresponding generally to the leading edge of excitation pulse 114. The sudden and continuous drop in speed which commences just prior to time t 8  represents agitator deceleration and ultimate stopping, resulting from the cessation of drive pulses. 
     In general, the dispenser in accordance herewith operates by in effect integrating the duration of time periods during which agitator speed exceeds a predetermined minimum or threshold level, represented for purposes of illustration by the threshold line 130 in FIG. 6. Further, the dispenser operates to produce the ultimate release of additive into the wash upon the occurrence of a predetermined agitator deceleration following the achievement of a predetermined agitator speed-time integration as just noted. More specifically stated, the first stage dispenser represented by receptacle 62 operates by centrifugally displacing and ejecting a predetermined charge of additive after a predetermined cumulative amount of time during which agitator speed exceeds a threshold level, which may occur during a single period on any combination of lesser periods. The additive which is so displaced through centrifugal force is received in the second stage of the dispenser, represented by receptacle 64. The priming and operation of siphon 80 which requires accumulation in receptacle 64 of substantially the entire predetermined charge initially placed in receptacle 62, as a minimum, together with a predetermined degree of agitator speed reduction. 
     This sequence of events is illustrated in FIGS. 7-13 inclusive, and may readily be appreciated by comparing one figure to another in that sequence. More particularly, as shown in FIG. 7 (the general condition at time t 1 ), the upper additive receptacle 62 has been filled with the desired quantity of additive 160, shown for illustration as substantially filling the volume in the cup-like receptacle 62 between its inlet strainer or filter 74 and rounded bottom extremity 100, having been poured in through the open inlet spout 72. Since cup 62 has imperforate walls throughout the area initially occupied by the additive 160, the latter will stay in place throughout washer operation involving agitator speeds less than predetermined threshold amount, as represented by the threshold line 130 in FIG. 6. 
     Accordingly, the additive 160 stays in the position shown in FIG. 7 throughout the initial wash action, involving lower agitator speeds, until the washer program commences spin activity, which may be increments of sub-interval spin or otherwise. In any event, as the drive motor 32 receives the pulse excitation previously described and illustrated in FIG. 5, it commences the course of acceleration illustrated by the velocity profile 116 in FIG. 6, and, as shown in the latter figure, at and just prior to the time t 2  agitator spin speed begins to exceed the preselected threshold level 130. At this point, the additive 160 has come to take the form shown in FIG. 8, in which a vortex has formed in the upper portion of the additive 160 and its upper surface defines a pronounced concavity 162 due to the effects of centrifugal force. Under these conditions, a first amount of additive 260 exits the upper receptacle 62 by creeping over its upper edge 62 a . The additive 260 which has departed the first or upper receptacle 62 migrates to the adjacent upper wall of the lower receptacle 64, where it is held in place by centrifugal force so long as the angular velocity of the agitator exceeds the threshold 130. As agitator Velocity decreases during the interval t 2  -t 3  following excitation pulse 102 and preceding the next excitation commencing at time t 3 , spin velocity decreases below threshold 130 and, as a result, the expelled quantity of additive 260 descends to the bottom of the second stage dispenser 64, where it is designated by the numeral 360. As illustrated, this amount of additive occupies only a relatively small amount of the total volume in lower cup 64, filling the well 94 and covering the siphon inlet 84 but being far below the top of the arch 96 at the top of siphon. Of course, the volume of additive 160 remaining in the upper receptacle 62 is now significantly less than it was previously, and its upper surface lies well below the strainer 74. 
     The procedure just discussed in connection with FIGS. 7, 8, and 9 continues as agitator speed increases in accordance with velocity profile 116, in response to successive pulses of drive motor excitation. Thus, at times t 4  and t 6 , represented by FIGS. 10 and 12, respectively, the vortex appearing in the top of the first receptacle 62 grows progressively deeper as agitator velocity increases and greater amounts of liquid 460, 660 are expelled outwardly and held by centrifugal force against the uppermost walls of the second-stage dispenser 64, and against the inside wall of the collar 70 at the top thereof, within spaces located between the reinforcement spacers. 
     During the final periods of acceleration, brought about by drive pulses 114 (FIG. 7) and occurring at times t 5  and t 7 , the ever-increasing angular velocity (spin rate) and corresponding high levels of centrifugal force ultimately brings the wash additive to the position shown in FIG. 12, wherein the additive is designated by the numeral 660. Under these circumstances, the entire charge of additive initially present in upper dispenser 62 is entirely disposed in a broad tubular vortex held high against the inside surface of the dispenser, with both dispenser cups 62 and 64 being emptied of the liquid. Following a predetermined period of maximum spin rate 124 (FIG. 5), occurring generally during the time t 7  -t 8 , drive excitation is terminated and agitator deceleration commences. When angular velocity decreases, the quantity of additive 660 is gradually drawn downwardly by the force of gravity into the lower extremity of the second stage dispenser 64 (FIG. 13) wherein it is designated by the numeral 760. As illustrated, when rotation stops, the quantity of additive 760 is now sufficient to cover the top of siphon tube 82, including the upper bend or arch 96 thereof. Accordingly, the siphon is primed and siphon action commences, whereupon the volume of additive 760 is drawn through the siphon tube 82 and discharged from its lower opening 86, from where it falls by gravity downwardly through the discharge tube 88, as illustrated by numeral 860. Once such siphon action commences, it continues until the entire volume of additive 760 has been drawn out of the second stage dispenser 64, since the presence of the concave well 94 in the bottom of the lower cup 64 will serve to collect substantially all of the minute quantities of additive from the very bottom on cup 64 and concentrate them in one area for removal by the siphon. Of course, once the additive has been discharged downwardly through the various openings provided in the mounting hub 48 and through the belled end of the agitator skirt 41, in the manner shown by the arrows in FIG. 3. From there, the additive works its way downwardly along the bottom surface of the wash basket 28, where it may mix with any water in the area, as may be present during an ensuing rinse cycle, or otherwise comes into contact with the wash load. 
     It will now be apparent that the novel dispenser in accordance with the invention provides a compound, staged dispensing action which requires a particular sequence of velocity and time before ultimately discharging the additive. Thus, depending upon specific configurations and design parameters which may be utilized, particular points in the wash cycle may be selected for discharge of additive, in the preferred embodiment illustrated and discussed such point being near the end of the wash cycle, after various changes in agitator speed, including &#34;sub-interval&#34; spins. Thus, the response of the present dispenser is complex in nature and, in essence, is based upon two mutually opposite conditions, i.e., progressive summing or integration of agitator spin time velocity exceeds a predetermined minimum threshold, until a predetermined total time unit has occurred, followed by a predetermined minimal period of agitator spin speeds below the aforementioned threshold level, under which condition the final tubular vortex of additive held against the outer periphery of the dispenser wall may progress downwardly and fill the siphon channel to thereby prime and actuate the siphon. Thus, the dispenser will only empty its contents into the wash after a particular combination of predetermined events have occurred, and premature emptying cannot take place since the siphon stage cannot operate until the full charge of additive is present in it and the agitator rotation has stopped. At the same time, by use of the siphon principle in the second stage dispenser, once the ultimate dispensing action commences it carries on without interruption until the full charge of additive is discharged. 
     As a final aspect of the novel dispenser apparatus, it is to be noted that the dispenser is be largely self-cleaning, in that any final rinses, or the initial fill upon washing the next load of clothes, will fill the tub 26, to a level at least as high as the lower dispenser receptacle 64, and thereby flood the hollow interior 46 of the agitator. When this occurs, water will pass upward through siphon tube 82 and flood the interior of receptacle 64, cleaning the same of all remnant quantities of the additive utilized in the previous washing operation. Of course, this is discharged back down through siphon tube 88, in the same general manner as was true of the additive dispensed earlier, at the end of the wash cycle. 
     It is to be understood that the foregoing description of a preferred embodiment of the invention i provided for purposes of the description and illustration, and not as a measure of the invention, whose scope is to be defined by reference to the ensuing claims. Thus, while those skilled in the art may devise embodiments of the particular concepts presented in the foregoing illustrative disclosure which differs somewhat from the particular embodiment shown and described in detail herein, or may make various changes in structural details to the illustrated embodiment, all such alternative or modified embodiments which utilize the concepts of the invention and clearly incorporate the spirit thereof are to be considered as within the scope of the claims appended herebelow, unless such claims by their language specifically state otherwise.