US 3346115 A
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Description (OCR text may contain errors)
O'Cf- 10, 1967 .1.c. MELLINGER l 3,346,115
METHOD AND APPARATUS FOR CENTRIFUGAL EXTRCTION Oct. l0, 1967 v .1.c. MELLINGER 3,346,115
METHOD AND APPARATUS FOR CENTRIFUGAL EXTRACTION Filed July 12', 1965 5 sheets-sheet s INCREMENTS OF TIMER ADVANCE ONTACTS 30 CYCLE OF ERA'r'loNs Oumma Drsr.
SPIN 'PuLsE PAusE BIPuLsE PAusE 6 PuLsE PAusE PuLsE DRY Aun/on Cool. Down Sua INTERNAL Sw|TcH|NG Patented Oct. 10, 1967 3,346,115 METHOD AND APPARATUS FOR CENTRIFUGAL EXTRACTION John C. Mellinger, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed July 12, 1965, Ser. No. 471,035 4 Claims. (Cl. 2141-78) This nivention relates to a laundry device incorporating an improved method for achieving optimum fluid extraction while substantially eliminating the problem of adhesion or of fabrics remaining adhered to the wall of the fabric container after termination of the extraction operation.
Fabric adhesion has long been recognized as a problern in washington machines. The addition of a fabric distribution operation prior to the centrifuging operation has greatly magnified the problem of fabric adhesion because of the increased tendency of fabrics to adhere to the wall of the container when uniformly distributed on the' periphery thereof. This problem of fabric adhesion is especially acute in a combination washer-drier since the drying operation immediately follows the extraction operation and freely tumbling fabrics are essential to a satisfactory drying operation.
Prior art patents incl-udc a number of attempts to solve this problem. One such patent, for example, has shown a method devised to prevent adhesion by the provision for extraction at an intermediate speed to remove the major portion of the retained fluid followed by a tumbling speed and then a final high speed spin to complete the extraction operation. Other prior art shows the provision for a series of intermediate speed extraction operations prior to the final extraction. S'tlll other prior art patents'use injected water directed upon the adhered fabrics to break them loose from the container wall following an extraction operation.
Extensive tests by the application have shown, however, that further improvements may be achieved. It is, therefore, an object of the present invention to provide an improved laundry device and method for operation thereof capable of achieving optimum fluid extraction while substantially eliminating fabric adhesion.
It is a further object of the present invention to provide an improved laundry device operable through a series of operations to achieve a preliminary fluid removal operation and a final high speed fluid extraction to realize optimum fluid extraction While avoiding fabric adhesion.
It is a further object of the present invention to 'provide a method of operating a laundry device through an improved cycle of operations including at least one material distribution operation and which is effective for achieving optimum uid extraction while avoiding material adhesion to the container;
It is a still further object of the present invention to providean improved laundry device and method of operationrthereof -to achieve preliminary fluid extraction, improved releasability of fabrics from the containter wall, and a final high speed spin to insure optimum fluid extraction without fabric adhesion.
The present invention achieves-the above objects inV tity of uids, at least one interrupted pause operation comprising a pause, a tumble impulse, and a second pause for stopping the container at two positions and allowing portions of the fabrics to fall free of the fabric container at these two positions, and a final fluid extraction operation.
Operation of the device and further obejcts and advantages thereof will become evident as the description proceeds and from an examination of the accompanying drawings which illustrate a preferred embodiment of the invention and in which similar numerals refer to similar parts through the'several views, wherein:
FIGURE 1 is a lrear View of the combination washerdrier of the instant invention with the cabinet back removed for showing the drive system;
FIGURE 2 is a side view showing a portion of the drive system of the combination washer-drier of FIG- URE 1 and further including a fragmentary sectional portion showing the drum and hub structure therefor;
FIGURE 3 is an electrical schematic diagram showing that portion of the circuit for the combination washerdrier of FIGURE 1 which pertains to the present invention;
FIGURE 4 is a cam chart showing the sequential operation of the switches included in the electrical circuit of FIGURE 3 durin-g that portion of the full cycle of operations of the combination washer-drier which pertains to the method of uid extraction of the instant invention; and
FIGURE 5 is a ca-m chart for the sub-interval switching included in the sequential control and shows the operation of the sub-interval switching during each increment.
Referring now to the accompanying drawings in detail, it Iwill be seen that the combination washer-drier unit shown in these drawings includes a substantially flat surfaced base frame 1 0 mounted on legs 11. Mounted upon base frame 10 are a pair of support members 13 and 14 which are welded, or securely affixed in some suitable manner, to the base frame 10 to form the two major supports for the washer-drier unit illustrated in the accompanying figures.
As apparent from a-n inspection of FIGURES 1 and 2, support members 13 and 14 have a channel cross section and a substantially triangular elevational configuration with the apex of these members receiving pivot pins 16 and 17. Pivot pins 16 and 17 support the bearing sleeves 18 and 19 and form a two-point support for the tub brackets 21 and 22, respectively. This allows the tub or casing, generally indicated by the arrow 24, and which is fastened to brackets 21 and 22, to oscillate back and forth on pins 16 and 17 in an arcuate movement in response to various forces generated Within tub 24.
Tub 24 is normally maintained in an upright position on pins 16 and 17 by the two centering springs 25 each of which is connected between base 10 and tub 24 by the spring anchor brackets 26 and 27 fastened to the base 10-and tub 24, respectively. Though not specifically shown, tub 24 is provided with a damper system including an upstanding damper plate 32, shown partially in FIGURE l, frictionally engaged by a damper pad (not shown) attached to and movable with tub 24. The energy imparted to tub 24, causes tub 24 to oscillate on the supporting pivot pins 16 Iand 17, and in turn is absorbed and dissipated by the relatively movable, frictionally engaged, damper pad and damper plate 32.
Tub orcasing 24 includes a generally cylindrical side wall-71V, a pair of spaced rear Walls 72 and 73, and a front wall 74. The front and outer rear walls 74 and 72, respectively, are connected to cylindrical side Wall 71 by means of the encompassing anged hoop-like members 76 While the partition wall 73 positioned between walls 72 Vand 74 is secured, as by welding, to side wall 71. It will be seen from an inspection of FIGURE 2 that the spaced rear walls 72 and 73 support the tub bearing assembly, generally indicated by the reference numeral 80.
The bearing assembly Si) includes a spacer hub 81 located between and abutting the rear walls 72 and 73, and a tubular clamp member S2 located concentrically within hub 81. Clamp member 82 is formed with a shoulder 35 at one end thereof `and has a threaded portion 84 at the other end thereof for receiving clamp nut 83 which, when tightened on member 82, produces a rigid support with respect to tub 24 for two bearings (not shown), with one located adjacent each of walls 72 and 73 Within hub 81 for supporting drive shaft 89.
The rear end of drive shaft 89 is rigidly c-onnected to the large drive pulley 91 whereas its front end is threaded into hub 94 of the fabric container 95. Container 95 includes a perforate rear wall 96 rigidly aflixed to and cooperable with a spider-like member 97 to form a double cone support connected to the hub 94 and providing a rigid support for the fabric container 95 on drive shaft 89. A sealing member 101 is biased against the rear surface of this revoluble hub structure 94 to prevent water from tub 24 from entering bearing assembly 80.
As apparent from FIGURE 2, container 95 also includes a perforate cylindrical side wall 104 carrying clothes elevating vanes 105. Side wall 104 merges into the short front wall 106 and joins flanged rear wall 96 in Ian overlapping relationship to form a protruding ange 108. Flange 108, while not touching wall 73, cooperates with it to form an effective air barrier for preventing the short circuiting of heated air around the rear peripheral edge of container 95 during the drying operations.
Tub 24 also includes a circular loading opening 117 encircled by one end of the bellows seal 118. The opposite end of bellows seal 118 is fastened to a similar opening formed in the cabinet 119. Sealing member 118 includes a number of convolutions 120 permitting movement of tub 24 relative to cabinet 119. A rectangular door 121 hinged on cabinet 119 carries a transparent glass window 122 having a cylindrical portion extending rearwardly through the bellows seal 11.8. The bellows seal is provided with a flexible `annular sealing lip 124 engageable with the periphery of the glass window 122. This arrangement seals the unit while enabling the operator of the machine to observe operations taking place within tub 24 during the washing and drying processes. Lamp 126, fastened to the exterior of tub 24, shines through `a transparent member 127 carried in the front wall 74 of tub 24 for illuminating the interior of container 95 during the loading or unloading operations thereof.
Tub 24 also includes a heater housing 131 which may be formed separately or as a part of the tub wall 71 for supporting and covering a heating element (not shown) capable of radiating heat energy into tub 24 through an opening located in the cylindrical tub wall 71. Heater housing 131 also mounts a thermostat 133 connected in series with the heater.
A combination blower-condenser unit capable of moving -air through tub 24, scrubbing 'lint from this air, and condensing out the moisture from hot yvapors formed within tub 24 during the drying operation, is positioned within the compartment formed by land between portions of the spaced walls 72 and 73. The compartment for the blower-condenser unit is produced by cooperation of walls 72 and 73 with an imperforate scroll-shaped side wall 136, shown by dotted lines in FIGURE 1 and which bridges the space between walls 72 Iand 73, to enclose the vapor condenser land blower unit.
An impeller (not shown) is positioned behind plate 13S and is driven by blower pulley 139. Plate 138 is bolted to the rear wall 72 or tub 24 and provides convenient access to the blower housing. Water for the vapor condensing process is supplied through the external conduit 141 and is directed into the blower-condenser compartment by ka conduit (not shown) connected between the cylindrical side wal-l 71 and the scroll-shaped wall member 136. Vapor laden air is moved from the interior of tub 24 by the action of the impeller and is moved through the blowercondenser compartment before being directed again toward the heater compartment or vented to the atmosphere.
More specific details of construction of this blowercondenser unit, and also of the aforementioned bearing assembly 80, may be f-ound in U.S. Patent 2,986,917 issued to T. R. Smith on June 6, 1961 and assigned to the assignee of the instant application.
Water for the washing operation is supplied through inlet 143 which directs fluid through conduit 144 into the interior of tub 24. Conduit 144 includes a trap portion 14S for preventing suds from escaping from tub 24 during the washing operation and preventing steam vapors from escaping from tub 24 during the drying operation.
Referring now to FIGURE 2, tub 24 includes a lower recessed portion forming a sump 149 communicating with the drain pump 159. Positioned in sump 149 is a perforate tray 151 for preventing foreign particles, which have passed through the perforate drum 95 into tub 24, from entering and damaging pump 1511.
Sump 149 receives the washing uids discharged into casing 24 and also receives from the blower-condenser compartment the condensing iiuid and the condensate and lint removed from the air entering the blower-condenser unit. The fluids and lint entering sump- 149 are discharged through pump 150 to van external drain (not shown). A valve 154, controlled lby solenoid 155, is positioned between purnp 150 and the external drain to control the discharge of uids to the external drain. Pump 150 is driven during washing operations by a pulley at 156; however, solenoid 150 is de-energized during the washing operations to maintain valve 154 closed iand uids within the tub 24.
Power to rotate container 95 is supplied by a drive system which includes a two-speed motor 160, a second motor 161, an overrunning clutch device 164, and belt transmission means including belts 165 and 166. As will be more fully explained hereinafter, this drive system is operable for providing a plurality of speeds of operation of the container 95 so as to achieve an optimum fabric treatment cycle. Specifically, this drive system is operable for providing a relatively slow tumble speed for accomplishing the washing action, a distribution speed for effecting arrangement ofthe fabrics in a substantially even pattern around the inner periphery of the container and becoming plastered thereto, and a relatively high speed spin for accomplishing fluid extraction.
Two-speed motor 160 includes a four-pole winding and a six-pole winding for operation of motor 160 at 1725 and 1150 r.p.m., respectively. The motor is further identied as a split-phase, unidirectional, fractional-horsepower motor of the type commonly used on laundry appliances.
As best shown in FIGURE 2, motor 160 is provided with shaft extensions at both ends for driving a plurality of components included in the combination washerdrier of the instant invention. Shaft extension 169 extending from the left end of motor 160, as viewed in FIGURE 2, supports a pulley 170 drivingly coupled by belt 171 to pulley 156 for driving pump 151). Pump 150 will therefore be driven during each period of operation of motor 160 but will be operative for pumping iiuid from tub 24 only during those periods when solenoid 15S is energized for opening valve 154.
Belt 171 is a round stretch belt and may be formed of a polyurethane material so as to possess the necessary characteristics for adjusting to variations in pulley center distances.
Shaft extension 174 extending from the right end of motor V1611, as viewed in FIGURE 2, carries pulleys 175 and 176 xedly mounted thereon. As best shown in FIG- URE 1, pulley 176 drives belt 165 drivingly connected to clutch device 164. Pulley 175 is drivingly engaged by belt 179 which in turn engages blower pulley 139.
Motor 160 is adjustably and pivotally mounted on tub 24 so as to provide for proper adjustment of tensions in belts 179 and 165. As best seen in FIGURES 1 and 2, motor 160 is secured to an inverted U-shaped bracket 181. U-shaped bracket 181 is formed with a pair of upturned tabs 191 for receiving pivot pin 194. Pivot pin 194 is supported by flange 195 of adjustable bracket 186. Bracket 186 is adjustably attached to brackets 185 and thereby secured to tub wall 71. Means are thereby provided for adjustably supporting motor bracket 186 to allow positioning of motor 160 along an arcuate path consisting of substantially vertically .related positions.
As viewed in FIGURE l, motor 160 is biased in a clockwise direction about pivot pin 194 by a coil spring 196 connected between motor bracket 181 and a bracket 199 fixed to the outer wall 71 of tub member 24. Though not specifically shown, bracket 199 is provided with a plurality of notches to facilitate the proper tensioning of spring 196.
The second motor 161 included in the drive system of the preferred embodiment of the instant invention is a single-speed, unidirectional, split-phase motor of `the fractional-horsepower type commonly used in laundry appliances. This motor 161 is also adjustably and pivotally supported relative to drum or tub member 24. A generally U-shaped bracket 200, similar to bracket 181, is secured to motor 161. Bracket 200 is pivotally supported by a bracket 205 on pivot pin 209.
Attached to bracket200 is a pivot .arm 210 `which pivots with bracket 200 around pivot pin 209. Spring 211 is connected between the end of pivot arm 210 and bracket 213, attached to wall 71 of tub 24, for biasing motor 161 in a blockwise direction about pivot pin 209. Bracket 213 includes a plurality of notches so as to provide means for increasing or decreasing the tension on spring 211 to maintain the proper positioning of motor 161 for controlling belt tension on belt 166.
Mounted on shaft 214 of motor 161 is an overrunning clutch device generally indicated by numeral 164. Clutch device 164 includes a first pulley member 215 rotatably mounted upon shaft 214 and driven by belt 165. A second pulley 216 is mounted on Shaft 214 for rotation therewith. Means are provided in clutch 164 for normally effecting engagement between pulley 215 and pulley 216 so as to effect rotation of pulley 216 at the same speed as pulley member 215. As previously indicated, pulley 216 is fixed to shaft 214 for rotation therewith. Upon energization of'motor 161, however, pulley 216 will rotate .at a speed in excess of that of pulley 215. This overrunning operation will effect disengagement of clutch 164.
Operation of the drive system of the instant invention is best shown by reference to FIGURE 1 and is basically a belt drive transmission having a pair of alternate drive paths. It will be seen that two speeds of operation are directly provided by the drive system. A first speed is obtained through the following drive path: motor 160 energized in its four-pole winding, a first speed reduction between pulleys 176 and 215, pulley 216 driven by pulley 215 through clutch 164, and a second speed reduction between pulleys 216 and 91. This drive path is operable for transmitting the torque of motor 160 to container 95 and for reducing the speed from a previously indicated motor speed of 1725 r.p.m. to a desired container speed of 60 r.p.m.
A second speed is obtained by selectively energizing motor 161 for driving pulley 216 at a higher speed than that of pulley 215 to rotate container 95 at a relatively high extraction speed through the single speed reduction between pulleys 216 and 91. With motor 1-61 operating at 1725 r.p.m. container 95 will be driven by pulley 91 at a speed of approximately 300 r.p.m.
l A third speed, whichin this embodiment is a relatively slow speed for achieving a tumble washing action, is obtained by cyclically energizing motor 160 for predetermined periods of time in either the four or six-pole windings to obtain a speed of operation relatively slower than that achieved by steady energizationon the four-pole winding. This pulsing of motor 160 for predetermined time periods may be controlled to provide a relatively constant speed tumble action at some speed between 40 and 60 r.p.m. but in this embodiment is spaced so as to provide a varying speed tumble action within the speed range of 40 to 60 r.p.m. .as will be more fully described hereinafter.
Means other than pulsing of motor 160 for obtaining another speed which is relatively close to the tirst speed are also available. A split, variable pulley with associated shifting means, for example, could also be used. In addition, a double grooved pulley with a belt shift device could be used.
Referring now to FIGURE 3, an electrical schematic diagram shows a selected portion of the components and circuitry required for the operation and control of the combination washer-drier embodying the instant invention. Generally, this view includes the components, controls, and related circuitry that are included in, or related to, the instant invention. The balance of the components and controls essential to the complete ope-ration of the washer-drier may be placed in the circuit'between L1 and L2. Provided across power lines L1 and L2 is conventional volt 60 cycle alternating current. Also, the circuit may be revised to include provision for 220 volt power if desired.
Upon selection of the variables and initiation of the desired cycle of operations, operation of the washerdrier combination unit is controlled by a sequence control mechanism 238 which includes a timing motor 239 for advancing a plurality of cams, or other switch operating means as represented by cam 240. These carns are operable for sequentially operating a group of switches to provide a programmed series of operations comprising a washing and drying operation. The switches of the sequential timing device are represented in the electrical circuit of FIGURE 3 by the group of contacts including contacts 243 through 247, 250, 251, 256 through 262, 267 and'268` which operate as pairs between the ope-n and closed positions under the control of cam members, such as cam 240, to energize and de-energize the various electrical components of the circuit of FIGURE 3.
Referring to FIGURE 4, there is shown a chart listing the above referenced contacts as cooperating pairs and including shaded areas showing those portions of the cycle when the pair is closed. The sequential control mechanism is operable through a cycle including 60 increments having a six degree spacing and one minute duration; however, the time chart is broken in the are-a of washing and tumble drying operations and only that portion pertaining to the instant invention is shown in detail. FIGURE 4 also shows a specific series of operations corresponding to'the switchingv as shown by the shaded portions therein.
It is believed that the electrical circuit of FIGURE 3 is best described by explaining operation of the device through the cycle of operations as shown in FIG'URE 4. Following energization of the machine, it will commence to till with washing Huid and motor will be energized to provide a tumbling speed for achieving a washing action. The circuit for energizing motor 160 includes power line L1, conductor 284, timer contacts 250, 251, and conductors 292 and 291. Conductor 291 is in turn connected to pulsing switch 294. An auxiliary timing motor 295 is energizable between conductor 292 and power line L2 through timer contacts 245, 246 to rotate cam member 296 for operating switch member 294.
Motor 160 includes start windings 301 in series With centrifugal start switch 299, six-pole run winding 302 in series with normally open switch 300, and four-pole run Winding 303. Centrifugal switch 299 is operable to,
7 an open position at a predetermined'speed of operation of motor 160 and is linked to switch 300 so as to operate switch 300 lfrom contact 306 to contact 307 at that lpredetermined speed.
After acceleration of motor 160 to a predetermined switching speed, switch 299 operates to the open position and switch 300 operates to close to contact 307, motor 160 becomes responsive to cyclic operation of switch 294 between contacts 304 and 305. Throughout the tumble operations of the wash and rinse portions, as shown in FIGURE 4, auxiliary timing motor 295 remains energized for cycling switch 294 betwee-n contacts 304 and 305 at predetermined time intervals for alternately energizing four-pole winding 303 and six-pole winding 302. Energization of four-pole run winding 303 for a period of approximately two seconds allows motor 160 to accelerate under normal operating conditions to its higher operating speed of 1725 revolutions per minute and allow operation at that speed for a period of time. This motor speed corresponds to a container speed of approximate-ly 60 revolutions per minute. Upon movement of switch 294 to contact 304 and energization of six-pole run winding 302, motor 160 will decelerate under the loading of container 95 and the material contained therein. Switch 294 is made to contact 304 for approximately three seconds, for example, to effect deceleration of motor 160 to approximately 1150 revolutions per minute. The three second period of time is normally sufficient to allow the motor to operate at this lower speed for a period of time for driving container 95 at a below normal tumble speed of approximately 4() revolutions per minute.
For a more specific and detailed explanation of this pulsing of a two-Speed motor to obtain an intermediate operational speed, attention is directed to United States Letters Patent No. 3,172,277, issued Mar. 9, 1965, by Charles W. Burkland and assigned to the same assignee as the instant invention.
The wash and rinse portion of the cycle of operations, as indicated in FIGURE 4, includes the tumble wash operation, removal of the wash fluids, a spray rinse and at least one tumble rinse.
In increment number 31, drain solenoid 155 is energized between power lines L1 and L2 through contacts 243, 244 for removing fluids from tub 24. Also, at this time, timer contact 246 is opened at contact 245 and closed to contact 247. With auxiliary timing motor 295 energized through pulsing switch 294 made to contact 304, cam 296 will be advanced only to the position at which switch i294 is operated from contact 304 to contact 305. Upon operation of switch 294 to contact 305, timing motor 295 will be de-energized and four-pole run winding 303 will be energized. The steady energization of four-pole run winding 303 will accelerate motor 160 to the four-pole operating speed corresponding to a container speed of approximately 60 r.p.m. for distributing fabrics around the inner periphery of container 95 in a substantially balanced pattern.
To accomplish a centrifugal extraction operation, a circuit is completed to run winding 315 of motor 161 from lpower line L1 through conductor 284, contacts 250, 251, conductor 292, contacts 261, 262 and through start relay coil 319, normally closed unbalance switch 320, conductor 324 and centrifugal switch 325 to line L2. Unbalance switch 320 is responsive to unbalanced loading within basket 95 and is operable to an open position to cle-energize motor 161. Centrifugal switch 325 is responsive to operation of motor 160 and is placed in this circuit to insure that motor 161 does not operate unless motor 160 is operating at speeds above that predetermined speed at which start winding 301 is de-energized. Completion of this circuit through relay coil 319 effects closing of switch member 326 for energizing start windings 331 through capacitor 332. When the current level through relay coil 319 drops to a predetermined level, which is achieved at a substantially less than normal operating speed for motor 161, coil 319 will allow switch member 326 to open for de-energizing start winding 331.
However, instead of proceeding immediately into a uid extraction operation following the nal rinse operation and the aforementioned drain and distribution operation, an improved procedure is followed to improve the release of fabrics from the inner wall of container upon completion of a fluid extraction operation.
It has been found that when materials are distributed or plastered around the inner periphery of the container and then submitted to high speed extraction for removing large quantities of fluids there is fabric adhesion, or the materials tend to remain adhered to the walls of the container even after it has stopped or returned to tumble speed.
In this application, adhesion is defined as that relationship which occurs between the fabrics and basket wall during extraction as evidenced by the fabrics failing to drop free of the basket wall upon termination of the extraction operation. Plastered is defined in this application as the arrangement of the fabrics around the inner periphery of the basket, the packing of these fabrics against the container wall, and the holding of them in this position by centrifugal force during the extraction operation.
To prevent this undesirable characteristic of adhesion, which becomes more pronounced when a distribution operation is provided, an improved sequence of operations is instituted following the nal rinse and drain operations, such a beginning in increment 33 of FIG- URE 4. This procedure includes a short-duration, relatively high speed, spin impulse for removing limited quantities of fluids from fabrics.
As previously shown, motor is operating to drive container 95 at a distribution velocity of approximately 60 r.p.m.; centrifugal switch 325 is thus in the closed position so that motor 161 is energizable for a spin operation. During the increment in which the spin impulse is desired, momentary-type switching, such as a subinterval switch 336 shown in FIGURE 3 as part of sequence control mechanism 238 under control of timing motor 239, is operative for closing contact pairs 339 and 340 for a momentary period of time. This switching is shown in FIGURE 5 and, in this embodiment, contact pairs 339 and 340 are individually operated so that both pairs are in the closed position, -as indicated by the shaded areas, for approximately 1.8 seconds of the total increment time of one minute. During this increment, timer contacts 258, 259 and timer contacts 256, 257 are closed to effect energization of spin motor 161 upon the momentary closing of contact pairs 339 and 340 by a circuit as follows: power line L1 through contact pairs 339 and 340, through timer contacts 258, 259 and through relay coil 319 to energize run winding 315. Upon energization of relay coil 319, starting switch 326 will close for energizing start winding 331. Since contact pairs 339 and 340 remain closed for only Iapproximately 1.8 seconds, run winding 315 will be maintained energized, through conductor 341, switch 326 and timer contacts 256, 257. Start winding 331 is also energized through switch 326.
It may, therefore, be seen that when motor 161 reaches a speed at which the current through relay coil 319 is insufficient to maintain switch 326 closed, relay coil 319 will allow switch 326 to open and de-energize motor 161. This switching speed occurs at approximately 1350 r.p.m. and corresponds to a basket speed of approximately 250 r.p.m.
It has been found that the amount or severity of fabric adhesion is a function of the quantity and rate of fluid flow through or from the fabrics undergoing fluid extraction. This quantity and rate of fluid flow are depen-dent upon extraction speed and duration. Therefore, it may be seen that with a slower acceleration, a ylonger duration or a lower top spin speed is allowable, for example, to maintain the proper balance between speed and duration. The
correct characteristics of the current sensitive relay must, therefore, be determined after consideration of the torque or acceleration characteristics of the motor being controlled. In addition, operation of a properly selected relay will effectively compensate for variations in line voltage. It is known in the electrical art that the current drawn by the run winding of a motor varies with the voltage and with the operating speed. At any given voltage, a plot of a speed vs. current curve shows that the cur-rent decreases with an increase in speed. A similar speed vs. current curve at -a lower voltage, for example, is displaced so that the current drawn at a given speed at the lower voltage is less than the current drawn at the higher voltage. The acceleration time to reach this given speed is, of course, greater at the lower voltage. Therefore, low voltage, which creates less torque and hence effects slower acceler-ation, is compensated for by reduced motor currents which in turn causes relay dropout at lower speeds. For example, a relay maybe selected for use in the instant preferred embodiment which would be operable in the, circuit of FIGURE 3 to give the following operational characteristics under varying voltage conditions:
It is noted that the basket in the preferred embodiment, having a diameter of 26 inches, does not reach the top extraction speed of y300 r.p.m. during the preliminary extraction; however,.the Vspeed and duration of the spin is sufficient to insure that .a limited, but large enough, portion `of the wateris removed from the materials contained therein withoutcausing adhesion of the materials to the inner wall ofthevcontainer. i
Following this spin impulse, the container returns to distribution speedn for theremainder of the increment. In prior art devices, the motor is then de-energized to allow the container to come to a restor energized for tumble speed for one incremenfoftimer `advance to thereby allow materials to fall free of the walls. Since only those fabrics' which are 4in the upper portions of the non-vertical axis container will fall free by gravity and since it has been found that a period of time must be allowed for the fabrics to fall, neither a tumble operation or an ordinary stopping of the container is fully satisfactory for allowing the fabrics to fall free. This is especially true where the clothes a-re evenly distributed and no large unbalanced groups of fabrics are present. It, therefore, becomes desirable, and an improvement over the prior art, to stop the container at a plurality or series of positions so that the fabrics in the various portions of the container will fall free.
Motor 160 is therefore interrupted to allow the container to come to a stopped position during a pause During this pause increment means are provided for momentarily reenergizing motor 160 to rotate container 95 for at least a portion of Va revolution or more than one revolution from said first stopped position to provide an additional rest position and thereby increase the opportunities for the materials to fall free from the periphery of the container by their own weight. Motor 160 is energized by a circuit from power line L1 through pulsing switch 336, timer contacts 259, 260, conductors 292, 291 to pulsing switch 294. Motor 160 is energized for a momentary period of time, such as the 1.8 second period of time during which both contact pairs 339 and 340 are in the closed position. The container 95 is then allowed to come to a second rest position for the balance of the pause increment. Additional stop positions may also be provided.
The fluid extraction operation may include additional spin operations` separated by a redistribution of fabrics.
The additional spin operations may include a distribution portion, a spin portion, and a pause and tumble impulse portion, but would not necessarily include the spin impulse. In the instant embodiment, three additional spin operations are included as indicated in FIGURE 4.
If a wash only operation is selected at the beginning, the machine would, following the final spin, proceed into a cool off period and then stop. If, however, a complete wash and dry operation is selected at the beginning, the machine proceeds to dry the materials within container following the final spin. Heater means and related controls and circuitry are included in the circuit to accomplish the tumble dry operation.
It may thus be seen that this laundry device includes a new combination of elements which have a cooperative interrelationship to achieve a degree of efficiency and consistency of results in washing 4and drying fabrics not heretofore realized in a single unit. This is a unit in which maximum fluid extraction is achieved through the provision for an assured distribution operation yet reduces the problems of fabrics adhering to the wall of the washing container through the provision for an anti-adhesion operation. There is greater assurance that fabrics will tumble freely during the drying operation so as to achieve optimum drying performance.
In the drawings and specification, there has been set forth -a preferred embodiment of the invention and, although speciiic terms are employed, these are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and the proportion of parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention as further defined in the following claims.
1. The method of centrifugal extraction of fluids from materials in a container revoluble about a non-vertical axis and having a foraminous wall member comprising the steps of effecting a period of acceleration of-said container toward an intermediate extraction speed for effecting preliminary extraction of fluids from said materials to substantially prevent Vadhesion of said materials to said container wall during'said period of accelerationand during subsequent high speed extraction; stopping said container in a first position for allowing a portion of the materials in said container to fall free from the upper region thereof by gravity; rotating said container for a short period of time at a speed not exceeding a fabric distribution speed for advancing said container to and stopping said container at at least a second position at which additional portions of said materials are allowed to fall free from the upper regions of said container by gravity; and rotating said container at a relatively high extraction speed for removing additional fluid from said materials.
2. The method of centrifugal extraction of fluids from materials in a container revoluble about a non-vertical axis and having a foraminous wall member comprising the steps of rotating said container at a relatively slow extraction speed to distribute materials around the inner periphery of Vsaid container wall member; effecting acceleration of said container toward an intermediate extraction speed at a rate which will substantially obviate adhesion of said-materials to said container wall and which will remove sufficient fluid to prevent adhesion during subsequent high speed extraction; effecting deceleration of said container to a first stopped position for allowing a portion of the materials in said container to fall free from the upper region thereof by gravity; rotating said container for a short period of time at a speed not exceeding said slow extraction speed for advancing said container to at least a second stopped position at which additional portions of said materials are allowed to fall free of the upper region of said container by gravity; rotating said container at said relatively slow extraction speed to redistribute materials around the inner periphery of said container wall member; and rotating said container at a relatively high extraction speed for removing additional uid from said materials.
3. In a laundry apparatus operable through a cycle of operations including washing and uid extraction, the combination comprising: container means rotatably mounted on a non-vertical axis and including a foraminous wall member; drive means operable for rotating said container means at tumble, distribution, and 'at least one extraction speed; control means including sequencing means for actuating said drive means at predetermined positions in said cycle of operation to selectively rotate said container means at said tumble speed for washing said fabrics and at said distribution speed for arranging the fabrics around the inner periphery of said wall member prior to operation at an extraction speed; said control means further including momentary switching means operative during an initial portion of said extraction operation for initiating energization of said drive means and relay means for maintaining said drive means energized for accelerating said container means toward an intermediate extraction speed, said relay means being operative at said intermediate speed during at least said initial portion of said extraction operation for de-energizing said drive means and for effecting deceleration of said container means to a first stopped position, said momentary switching means being operable after a first time delay during which said container means is in said first stopped position for energizing said drive means for a short period of time to rotate said container means at a speed not exceeding said distribution speed for advancing said container means to a second stopped position whereby said container means is stopped in at least two positions for allowing fabrics to fall free from the upper portion of said container means, said control means being further operative for energizing said drive means after a second time delay during which said container means is in said second stopped position to eifect rotation of said container means at a relatively high extraction speed.
4. In a laundry apparatus operable through a cycle of operations including washing and uid extraction, the combination comprising: container means rotatably mounted on -a nonvertical axis and including a foraminous wall member; drive means operable for rotating said container means at a pluraity of speeds including tumble, distribution, and extraction; control means including sequencing means for energizing said drive means `at predetermined positions in said cycle of operations to selectively rotate said container means at said tumble speed for washing said fabrics and at said distribution speed for arranging the fabrics around the inner pehiphery of said wall member prior to operation at an extraction speed; said control means further including momentary switching means operative during an initial portion of said extraction operation for initiating energization of said drive means; and relay means responsive to operation of said momentary switching means for maintaining said drive means energized for accelerating said container means toward an intermediate extraction speed, said relay means being responsive during said initial portion of said extraction operation to operation of said drive means at said intermediate speed for de-energizing said drive means and for effecting deceleration of said container means to a rst position; circuit means included in said control means operative for energizing said drive means for a short period of time to rotate said container means at a speed not exceeding said distribution speed for advancing sai container means to a second position whereby said container means is located in at least two positions for allowing fabrics to fall free from the upper portion of said container means, said control means being further operative for energizing said drive means to effect rotation of 'said container means at a relatively high extraction speed.
References Cited UNITED STATES PATENTS 2,760,639 8/ 1956 Haverstock 210--78 X 3,194,398 7/1965 Fecho 210-78 3,209,381 10/1965 Toma 68-24 X REUBEN FRIEDMAN, Primary Examiner.
SAMIH N. ZAHARNA, Examiner.
I. DE CESARE, Assistant Examiner.