Patent Application
20050210931
1. Field of the Invention
The present invention pertains to the art of washing machines and, more particularly, to a balancing fluid reservoir and delivery system for an out-of-balance control system provided to correct an out-of-balance condition of an inner tub of a washing machine.
2. Discussion of the Prior Art
During operation of a washing machine, it is not uncommon for an inner tub or spinner, which is rotatably mounted within the washing machine, to become unbalanced due to a particular distribution of a load of laundry. During the course of a typical wash cycle, the inner tub is rotated at a relatively high or extraction speed to extract water absorbed by the laundry. If the laundry is unevenly distributed within the inner tub during the extraction phase, an out-of-balance condition will develop. This out-of-balance condition, when rotated at the extraction speed, can cause excessive vibration.
Certainly, excessive vibration is detrimental to the continued operation and reliability of the machine. Accordingly, the prior art contains several examples of vibration or out-of balance detection systems for sensing an actual or incipient unbalance condition. In addition, it is known to correct the out-of-balance condition without interrupting operation of the washing machine even after exceeding a predetermined vibration threshold. In general, prior art systems function to reduce the rotational speed of the inner tub, provide a means of re-balancing the inner tub or, less desirably, entirely shut down the machine until a consumer corrects the problem by physically redistributing the laundry within the machine.
Systems for re-balancing an out-of-balance washing machine are well known in the prior art. Examples of such systems are described in U.S. Pat. Nos. 3,983,035 and 4,991,247. In each of these systems, the out-of-balance condition is corrected by injecting a balancing fluid into a container located on an inner peripheral portion of a rotating inner tub. Nozzles or other water inlets are adapted to rotate with the inner tub and, upon receiving a particular control signal, dispense a predetermined amount of balancing fluid into the container(s) which eventually counteracts the out-of-balance condition. The structure required to enable each nozzle to rotate with the inner tub, maintain a fluid connection between the nozzles and a central supply, and to provide a separate supply to each container requires a complicated arrangement of components which substantially increases the cost of the appliance. In addition, it has been found that systems which do not include containers for receiving the balancing fluid on both front and rear portions of the rotating tub require a larger amount of balancing fluid and, moreover, require a longer time period to facilitate correction of the unbalanced condition which could expose the appliance to unacceptable vibration levels.
In addition to the above, there exist a number of complications associated with delivering the balancing fluid to the containers. Specifically, complications exist with controlling the amount of fluid introduced into the containers. When using a pressurized system, precise control of the fluid is difficult to achieve. Namely, when the fluid column is under pressure, it is difficult to accurately control the amount of balancing fluid introduced into the containers. A valve is cycled rapidly and repeatedly to direct the balancing fluid into the rotating inner tub. Rapid opening and closing of the valve must both initially accelerate the balancing fluid and then subsequently stop the forward motion of the fluid stream. When the fluid is under pressure, i.e., when the fluid is brought up from a reservoir located below the container, stopping the forward motion of the fluid stream is often difficult. Once the valve is closed, the fluid develops a tail that extends from the valve until the cohesive bonds within the fluid stream break. This will result in either too much fluid being dispensed into the container or, alternatively, fluid being placed into the wrong container. In either case, correcting the unbalanced state becomes a more difficult and lengthy process.
While the above described systems for correcting an out-of-balance condition in a washing machine are effective to a degree, there still exists a need in the art for a system which will more efficiently correct an unbalanced condition by using a unpressurized fluid flow. Furthermore, there exists a need for an improved unbalance correction system which is simple in construction and operation, so as to be both reliable and cost effective.
A washing machine constructed in accordance with the present invention incorporates a system for storing and delivering an un-pressurized balancing fluid to correct an out-of-balance condition. More specifically, the present invention is directed to a washing machine including an outer tub having a rear portion including inner and outer surfaces, a main body portion extending from the rear portion to a terminal rim, and an inner tub supported for rotational movement within the outer tub. In accordance with a preferred form of the invention, a balancing fluid reservoir is integrally molded to an upper surface of the main body portion. The reservoir includes a first or upper opening adapted to receive the balancing fluid and a second or lower opening adapted to dispense the balancing fluid.
A plurality of balancing fluid channels are integrally molded into the outer surface of the rear portion of the outer tub. Each of the channels includes a first end open to the fluid reservoir and a second end having a valve seat opening to an interior portion of the outer tub. In a preferred arrangement, the plurality of balancing fluid channels constitute first and second fluid delivery channels adapted to conduct fluid from the reservoir, and a third or fluid return channel that partially defines a return path to the reservoir. Each of the plurality of channels is separated by a respective raised wall portions and, preferably between the first and second channels, a double wall portion. The plurality of channels are closed off by a cover plate secured to the raised wall portions. More specifically, the cover plate includes first and second cylindrical receiver openings for securing injector valves relative to the first and second channels. With this arrangement, the valves, located in the receiver openings are capable of injecting calculated amounts of balancing fluid into particular portions of the inner tub.
The invention provides a relatively simple, inexpensive unbalance correction system which is able to accurately remedy an out-of-balance condition sensed by an unbalanced detection assembly. In any event, additional objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention, when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.
With initial reference to
In accordance with one embodiment of the present invention, laundry appliance 2 is shown to include a control panel 16 arranged on an upper rear portion of cabinet shell 4. In the embodiment depicted, control panel 16 includes a plurality of cycle setting buttons 20-22, a start/stop button 23 and a rotary control knob 24. Buttons 20-22 and control knob 24 are utilized to establish a desired washing operation for laundry appliance 2. Since the general setting and operating of laundry appliance 2 is known in the art and does not form part of the present invention, these features will not be discussed here in detail. However, in general, buttons 20-22 are used to manually set desired operational parameters, including a desired fill level based on load size, wash and rinse temperatures, along with the type of washing operation, such as gentle, normal or the like cycles, typically based on the particular fabrics being washed. On the other hand, control knob 24 is used to set the type and duration of the washing operation. Although control panel 16 is shown to include buttons 20-22, start button 23 and control knob 24, it should be understood that these particular types of control elements are merely intended to be exemplary and that other types of control elements, including electronic control elements, soft touch buttons, a touch screen LED panel and the like could be readily utilized.
Arranged within control panel 16 is a control unit or CPU 39. Control unit 39 includes unbalance detection circuit 41 for detecting actual or incipient unbalanced load conditions occurring within inner tub 8. Typically, during a spin cycle, a particular distribution of laundry within inner tub 8 may lead to an out-of-balance condition when inner tub 8 is rotated at high speed which can generate excessive vibrations of laundry appliance 2. It should be understood that, at this point the details of unbalance detection circuit 41 are not part of the present invention and can actually take various forms, such as that disclosed in commonly assigned U.S. Pat. No. 6,422,047 which is hereby incorporated by reference. In any case, unbalance detection circuit 41 receives signals from an unbalance detecting unit (not shown) and, depending on these signals, provides inputs to tub drive control 44, cycle control 46 and unbalance correction controls 47 which, in turn, provides the control to the on-axis injection system of the present invention as described more fully below.
Referring to
In accordance with a preferred embodiment of the present invention, the balancing fluid is delivered to inner tub 8 through a plurality of fluid delivery or receiving channels which are, at least partially, molded onto a rear portion 60 of outer tub 9. More specifically, as will be detailed more fully hereafter, first and second fluid delivery channels 70 and 71 carry the balancing fluid from reservoir 53 to particular pockets carried by inner tub 8. A third, drain or return channel 73 is further provided on rear portion 60 of outer tub 9 to collect expended balancing fluid from inner tub 8 and ultimately carry the fluid back to reservoir 53 through a hub portion 76. As shown, a plurality of raised wall portions 77-81 extend from hub portion 76 and thereafter separate and define each of the first, second and third channels 70, 71 and 73. Furthermore, in order to reduce the possibility of fluid leaking between first and second delivery channels 70 and 71, a segment of wall portion 81 includes a double wall segment 83. Finally, in addition to partitioning the fluid channels 70, 71 and 73, raised wall portions 77-81 and 83 increase the stiffness and thus the structural integrity of outer tub 9.
In accordance with a preferred arrangement, first and second fluid delivery channels 70 and 71 open to reservoir 53 at respective upper portions 90 and 91. From upper portions 90 and 91, balancing fluid delivery channels 70 and 71 extend along rear portions 94 and 95 of outer tub 9 before opening to delivery channels 99 and 100 at hub portion 76. Preferably, rear portions 94 and 95 are formed with a minimal number of undulations or the like which could lead to inconsistency in balancing fluid delivery. Similarly, a drain opening 105 leads from hub portion 76 to an upper or inner radial portion of drain channel 73. As will be detailed more fully below, as the balancing fluid returns from inner tub 8, it passes along hub portion 76 to drain opening 105 traveling along a rear portion 106 prior to being returned to reservoir 53 as will be discussed more fully below.
In order to ensure the existence of a proper pressure head, as well as to fully close off the delivery system, a cover plate 120 is secured to raised wall portions 77-81 and 83 on outer tub 9. As shown, cover plate 120 is defined by an outer contour 121 corresponding to raised wall portions 77-81 and includes a notched portion 123 adapted to partially extend about hub portion 76. As further shown in
Although further details of injector valve assemblies 135 and 135′ will be provided hereafter, in general, each of injector valve assemblies 135 and 135′ includes at least an outlet or base portion 145 having a curvilinearly tapered end portion 146 adapted to matingly seat in a respective outlet delivery channel 99 and 100, an intermediate portion 147 and a valve coil 148. Most preferably end portion 146 evinces a generally spherical profile that has been truncated. In a preferred form of the invention, injector valve assemblies 135 and 135′ are secured within respective cylindrical receivers 130 and 131 through a plurality of raised mounting lugs 155-158 arranged adjacent to each cylindrical receiver 130, 131. More specifically, injector valve assemblies 135 and 135′ are secured to mounting lugs 155-158 through respective bracket members 165 by a plurality of mechanical fasteners 170-173. In a more preferred form, a resilient ring 175 is positioned between valve coil 148 and mounting bracket member 165 to account for any excessive vibrations or misalignment problems with respect to injector assemblies 135 and 135′ within outlet delivery channels 99 and 100.
Opening from a lower portion of cover plate 120 is a drain conduit 180 which directs returning balancing fluid from drain channel 73 to reservoir 53. In accordance with a preferred embodiment of the present invention, drain conduit 180 interconnects to reservoir 53 through a pump (not shown) which functions to return the balancing fluid from drain channel 73 to reservoir 53. In accordance with another embodiment of the present invention, drain conduit 180 interconnects with an intermediate sump and pump (not shown) adapted to store the used balancing fluid until demanded through correction controls 47. In any event, it is only important to note that the balancing fluid is preferably returned to reservoir 53 in a manner so as to define a closed system. In this way, there is no further need to add balancing fluid once laundry appliance 2 leaves the factory.
Referring to
Rear portion 200 of spinner body member 190 is closed off by cover plate 195. As best seen in
Referring to
With this arrangement, balancing fluid can be dispensed into any combination of rear and front plane pockets 210-217, 232-235 to compensate for an out-of-balance condition of rotating inner tub assembly 8. With specific reference to
As will be detailed more fully below, once inner tub assembly 8 ceases to spin, the need for balancing fluid in either rear injection zone 200 or front injection zone 203 is eliminated. Accordingly, as the radial velocity of inner tub 8 decreases, so does the centrifugal force holding the balancing fluid within a particular pocket 210-217 and 232-235. As the force continues to decrease, the balancing fluid begins to migrate to shaft member 204 and collect in recess 275 (
Upon sensing an actual or incipient out-of-balance condition, correction controls 47 signals the on-axis injection system to dispense an out-of-balance correcting balancing fluid into particular portions of inner tub assembly 8. In order to offset the out-of-balance condition, correction control 47 determines into which plane and into which pocket in that plane an injection of balancing fluid is required. At this point, a timing mechanism (not shown) timely activates one of the pair of injectors 135 and 135′ corresponding to the particular injection zone 200 and 203 into which an injection of fluid is necessary. Reference will now be made to
In accordance with a preferred embodiment as discussed above, injector 135 takes the form of a solenoid type valve and includes base portion 145 having curved or tapered end portion 146, an intermediate portion 147 and valve coil 148. More specifically, end portion 146 includes a first end defining an outlet opening 283 and a second end having an inner surface portion 286 defining a central recess 288. Extending between outlet opening 283 and an inlet opening 290 is a delivery conduit 292 having a central passage 293. Preferably, delivery conduit 292 is integrally molded to base portion 145 and includes a plurality of tapering rib elements 297-299. More specifically, rib elements 297-299 support delivery conduit 292 and define a balancing fluid inlet or supply opening 305 (
In accordance with the preferred embodiment shown, inlet opening 290 is adapted to be selectively sealed through application of a diaphragm 319 positioned along inner surface portion 286. More specifically, diaphragm 319 includes surface 323 which extends into and seals about central recess 288. As best seen in
More specifically, as best shown in
Experience has shown that repeated operation of the valve results in wear to both second end 337 and pole piece 344 causing the calibration of valve assembly 135 to exceed manufacturer specifications. However, by incorporating cushioning ring 340 into second end portion 337, the life of valve assembly 135 can be extended such that prolonged operation is possible. In addition, cushioning ring 340 helps control the physical profile of the balancing fluid dollop as it passes from outlet 283. Because of the critical role that cushioning ring 340 plays in the performance of valve assembly 135, it would generally be considered desirable to have pole piece 344 as smooth as possible to minimize wear on cushioning ring 340. However, each time cushioning ring 340 contacts pole piece 344, an amount of air is trapped within a center portion 345 of cushioning ring 340. Because the force between pole piece 344 and plunger 335 becomes large as plunger 335 approaches pole piece 344, the pressure of the trapped air can become high and air may leak from the center of cushioning ring 340 in an uncontrolled manner.
When the electrical power to valve coil 148 is removed, plunger 335 moves away from pole piece 344. If air has leaked from the center of cushioning ring 340, then a vacuum may be drawn within cushioning ring 340 to retard or prevent the movement of plunger 335, which undesirably changes the amount and location of the injected fluid. In order to alleviate the problem of trapped air, pole piece 344 is subject to a texturing process wherein the surface of pole piece 344 is formed with channels, notches, grooves, or the like. With this arrangement, trapped air can escape from center portion 345, thereby enabling plunger 335 to fully retract into bore 343 without excessive pressure build-up. Further, the texturing provides a path for air to reenter center portion 345 as plunger 335 is released so that vacuum does not retard plunger motion. It should be understood that a polished pole piece may work satisfactorily for some applications, but where cycle-to-cycle consistency is desired, a roughened or textured pole piece 344 offers more consistent performance. Finally, a coil spring 348 is arranged about plunger 335 to bias diaphragm 319 against inlet opening 290 during periods of inactivity.
With further reference to
Valve assemblies 135 and 135′ are selectively activated though application of voltage to electrical terminals 380 and 381 (
As best seen in
Referring to
Upon sensing an unbalanced condition of inner tub 8, unbalance detection circuit 41 in CPU 39 determines the magnitude and location of the unbalanced condition. At this point, correction control 47 calculates the amount of balancing fluid, and into which one of the plurality of pockets 210-217 and 232-235 to inject the balancing fluid to offset the unbalanced condition. More specifically, a timing mechanism (not shown) monitors the position of the inner tub 8 relative to injectors 135 and 135′. Through use of the timing mechanism, unbalance correction control 47 operates the appropriate one of injectors 135 and 135′, at a proper time and for a desired duration, to dispense the calculated amount to fluid into the requisite pocket 210-217, 232-235. Centrifugal force, generated by rotating inner tub 8, forces the balancing fluid into the appropriate one of the plurality of pockets 210-217, 232-235. This process repeats itself until the unbalance condition is corrected as sensed by unbalance detection circuit 41. As indicated above, once the centrifugal force keeping the balancing fluid within the particular pocket 210-217, 232-235 diminishes sufficiently, the balancing fluid, under force of gravity, returns to drain channel 73. As shown in
As shown in
Although described with reference to a preferred embodiment of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, the exact construction and location of the reservoir could vary without departing from the scope of the present invention. In general, the invention is only intended to be limited by the scope of the following claims.
