US3691797A

US3691797A - Liquid control system for washing machine

Info

Publication number: US3691797A
Application number: US159825A
Authority: US
Inventors: Thomas R Smith
Original assignee: Maytag Corp
Current assignee: Maytag Corp
Priority date: 1971-07-06
Filing date: 1971-07-06
Publication date: 1972-09-19
Anticipated expiration: 1989-09-19
Also published as: CA982836A

Abstract

A liquid control system for a washing machine having a bidirectional motor operable for effecting washing and extraction operations includes a one-way check valve in the drain conduit. The liquid control system includes a pump driven by the motor and operable for pumping toward and from a tub during the washing and extractions, respectively, with the check valve being self actuating for permitting flow from the tube during the extraction operation and preventing backflow to the tub at the conclusion of the extraction operation and during the washing operation to effectively obviate mixing of the washing liquid with residual liquid from the previous cycle.

Description

United States Patent Smith LIQUID CONTROL SYSTEM FOR WASHING MACHINE [72] Inventor: Thomas R. Smith, Newton, Iowa [73] Assignee: The Maytag Company, Newton,

Iowa

[22] Filed: July 6,1971

[2]] Appl.No.: 159,825

[52] U.S.Cl.... ..68/23.4

[51] Int. Cl. ..D06f 39/08 [58] Field of Search ..68/23.4, 208

[56] References Cited UNITED STATES PATENTS 2,923,144 2/1960 Smith ..68/208 X 2,924,959 2/1960 Israel ..68/208 X 2,972,877 2/1961 Platt ..68/208 X 3,027,908 4/1962 Cochran ..68/208 X 3,078,861 2/l963 Miller.., ..68/208 X [451 Sept. 19, 1972 FOREIGN PATENTS OR APPLICATIONS 636,598 5/l962 Italy ..68/208 Primary ExaminerWilliam I. Price Attorney-William G. Landwier et a].

[5 7 ABSTRACT A liquid control system for a washing machine having a bidirectional motor operable for effecting washing and extraction operations includes a one-way check valve in the drain conduit. The liquid control system includes a pump driven by the motor and operable for pumping toward and from a tub during the washing and extractions, respectively, with the check valve being self actuating for permitting flow from the tube during the extraction operation and preventing backflow to the tub at the conclusion of the extraction operation and during the washing operation to effectively obviate mixing of the washing liquid with residual liquid from the previous cycle.

8 Claims, 5 Drawing Figures LIQUID CONTROL SYSTEM FOR WASHING MACHINE SUMMARY OF THE INVENTION This invention relates to a liquid control system for a washing machine and more particularly to a system including a check valve and operable for preventing intermixing of residual liquids remaining in the drain conduit with the fresh washing liquid.

In the art of washing machines, the prevention of intermixing of the washing liquid with residual liquid from the previous washing cycle is receiving increasing attention. In some constructions, the washing container is effectively isolated from the liquid basin so that the problem of liquid intermixing is obviated, but in other constructions, a perforate washing basket is disposed within a generally imperforate outer liquid tub having a conduit communicating with the drain. In' these constructions, washing liquid that is pumped from the outer tub toward the drain is substantially removed from the washing machine but a residual quantity remains in the drain conduit and may be of sufficient quantity to return to the outer tub upon interruption of the pumping operation and upon the liquid seeking a static level. I

The potential objection to residual washing liquid intermixing with washing liquid for succeeding cycles is even greater in washing machines in which a bidirectional drive system operates in one direction to effect washing operation and in the opposite direction to effect a centrifugal extraction and pumping operation. With this type of drive system the pump is effectively operable for pumping liquid toward the tub from the drain hose during the washing operation.

It is therefore an object of the instant invention to provide an improved washing machine liquid control system operable for preventing intermixing of residual liquid from a previous operation with fresh washing or rinsing liquid.

It is a further object of the instant invention to provide an improved washing machine control system having a one-way check valve disposed between the liquid container and the pump. operable in It is a further object of the instant invention to provide, in a washing machine having a bidirectional drive system operable for pumping liquid from the tub during an extraction operation and toward the tub during a washing operation, a liquid control system including a check valve disposed between the pump and the outer tub to prevent intermixing of residual liquid from a previous operation with the fresh liquid in the tub.

It is yet a further object of the instant invention to provide an improved liquid control system for a washing machine and including a check valve disposed between the tub assembly and the pump for permitting pumping of liquid from the tub assembly and operable for preventing backflow of liquid into the tub in the absence of pumping and for preventing liquid flow into the tub assembly from the drain system under high pressure reverse pumping conditions.

These objects are achieved in a liquid control system for a washing machine wherein a one-way check valve is disposed between the liquid-containing tub assembly and the pump and is self actuable to a sealed condition with a low urging force for preventing low pressure liquid flow into said tub assembly and further responsive to a higher urging force for preventing high pressure liquid backflow into said tub assembly to avoid intermixing ofliquid in the washing container.

Operation of the device and further objects and advantages thereof will become evident as the description proceeds and from an examination of the accompanying two pages of drawings.

DESCRIPTION OF THE DRAWINGS The drawings illustrate a preferred embodiment of the invention with similar numerals referring to similar parts throughout the several views wherein:

FIG. 1 is an overall view of an automatic washing machine with various portions broken away to show components of the improved liquid control system of the instant invention;

FIG. 2 is a longitudinal sectional view of the check valve construction used in the liquid control system of the instant invention as taken along lines 2-2 of FIG.

FIG. 3 is a transverse sectional view of the inlet portion of the check valve as taken along lines 33 of FIG. 2;

FIG. 4 is an enlarged fragmentary sectional view of the low pressure sealing condition of the check valve; and

FIG. 5 is a fragmentary sectional view similar to FIG. 4 showing a high pressure sealing condition of the check valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown an automatic washing machine including a base frame 10 supported on a plurality of adjustable legs 11 and mounting a cabinet 13 comprising sidewall portions 14 and a top cover portion 15. The top cover portion 15 includes a hinged door panel 16 normally covering a recessed loading opening 19 and further includes an upwardly extending housing 20 for accommodating various control members such as programming means actuable by the dial 21.

Mounted within the cabinet 13 is a tub assembly 23 nutationally supported on the base frame 10 by an inverted tripod arrangement including tub braces 25 which are connected at the lower end to a support member 26 positioned on the base frame 10. The tub braces 25 are connected at their upper ends to a generally imperforate outer liquid container or tub 29. The tub braces 25 are also resiliently connected to the base frame 10 by means of centering springs 30 which resist rotation of the support member 26 relative to the base frame 11 but permit nutational movement relative to the base frame 1 1.

Revolubly mounted in the imperforate outer tub 29 is a perforate clothes basket or inner tub 31 in which is positioned an oscillatable agitator 33 for effecting movement of fabrics and washing liquid within the tub assembly 23. The imperforate outer tub 29 and the perforate inner tub 31 are substantially aligned with theloading opening 19 in the top cover 15 for permitting the operator to place fabrics within the inner tub 31 and to remove them upon completion of the cycle. thru inclusive shown The base frame also supports, through a motor mount 34, a reversible drive motor 35 operable in a bidirectional drive system for selectively effecting oscillation of the agitator 33 or centrifugal rotation of the inner tub 31. The drive system for selectively effecting operation of the agitator 33 and rotation of the inner tub 31 includes a double groove pulley 36 fixed to the shaft of motor 35 and drivingly engaged with a main drive belt 39 which in turn is drivingly engaged with the main drive pulley 40. The main drive pulley 40 is drivingly 99 with the main drive pulley 40. The main drive pulley 40 is drivingly connected to either the agitator 33 through a drive shaft (not show) and the gearing of a transmission 41 or to the inner tub 31 through the housing of the transmission 41 and a clutch (not shown).

Operation of the motor 35 in a first direction effects rotation of the main drive pulley 40 for effecting oscillation of the agitator 33 through the drive shaft (not shown) and transmission gearing. Operation of the motor 35 in the opposite direction effects rotation of the drive pulley 40 and the transmission 41 through the clutch (not shown) for rotating the inner tub 31 to effect centrifugal extraction of liquid from fabrics within the inner tub 31. g

The washing machine is provided with controls for programming the machine through a sequence of operations including energization of the motor 35 for operation in a first direction to effect a washing and/or rinsing function followed by energization of the motor 35 in a second direction to effect a liquid extraction function.

The construction and mounting of the tub assembly 23 and the operation of the inner tub 31 and agitator 33 for effecting washing and extraction operations are more clearly and specifically shown in the following patents, each of which is assigned to the assignee of the instant invention: Scott et al. US. Pat. No. 2,854,297; Smith et al. US. Pat. No. 2,926,136; Burkland U.S. Reissue Pat. No. RE 25,157; and Goodlaxson US. Pat. No. 3,013,645.

The base frame 10 also supports a pumping means 42 that is driven by the bidirectional motor 35 through the motor-mounted pulley 36, the pump drive belt 43 and the pump-mounted pulley 44. The pump 42 communicates with the outer tub 29 through a conduit 45 and is operable for carrying liquids the the outer tub 29 and pumping them toward an external drain through a drain hose 49 and standpipe 50 when the motor 35 is operated in the direction for effecting centrifugal rotation of the inner tub 31. Since the pump 42 is drivingly connected to the bidirectional motor 35 and is operable in the first and second directions with the motor 35, the pump 42 will tend to pump liquids toward the outer tub 29 through the conduit 45 when the motor 35 is operating in the direction for effecting agitation of the fabrics during the washing portion of cycle.

In installations of the washing apparatus wherein a relatively long elevated drain hose is provided or wherein a standpipe drain is utilized as in FIG. 1 the drain hose 49 is capable of retaining a significant quantity of liquid at the termination of the pump-out or extraction period. This retained liquid, in the absence of a check valve in the line between the pump 42 and the outer tub 29, tends to return toward the outer tub 29 as the liquid seeks a stabilized level. This backflow of liquid toward the outer tub is considered by some as undesirable since there may be intermixing of the residual used washing liquid with the fresh washing liquid of the succeeding cycle and it is therefore preferred that the backflow into the outer tub be prevented.

As will be shown in greater detail hereinbelow, a check valve assembly 51 in the liquid system of the instant invention is operable for permitting relatively free liquid flow from the outer tub 29 to the pump 42 and thus to the drain during pump out while preventing backflow of used washing liquid into the outer tub 29 upon termination of the pump out and during the succeeding washing operation.

Referring to FIG. 2, there is shown a longitudinal sectional view of the check valve assembly 51 as used in the liquid control system for preventing the backflow of washing liquid into the washing container of a fabric washing apparatus for example. The check valve assembly 51 is connected between the outlet 53 of the outer tub 29 and the fluid conduit 45 leading to the pump 42. The check valve assembly 51 includes a housing 55 formed of a relatively rigid plastic to which the fluid conduit 45 is connected at the lower end by a clamp 56. The check valve assembly 51 further includes an upper tubular member 59 formed of a resilient elastomer material and retained on the tub outlet 53 by a clamp 60. An enlarged portion 61 of the housing 55 internally receives a flange portion 63 of the tubular member 59 and the mating parts are securely held together by a retaining ring 64. The enlarged portion 61 of the housing includes a plurality of radially inwardly extending ribs 65, as best shownin FIG. 3, which are aligned with grooves 66 in the retaining ring 64 for initial assembly. The retaining ring 64 is then rotated, such as with a tool engageable with holes 67, cut into the ribs 65 to securely connect the housing 55 to the tubular member 59. A washer 69 is disposed between the retaining ring 64 and the flange portion 63 of the tubular member 59.

The check valve assembly 51 further includes a thin pliable resilient seat member 70 disposed between the flange portion 63 of the tubular member 59 and the housing 55. The seat member 70'includes an outer annular ring 71 mating with a groove 73 in the housing 55 and is retained in position by the clamping action between the flange portion 63 and the offset in the housing 55. The seat member 70 includes a thin annular lip 74 extending into the housing passageway and defining a sufficiently large central opening to permit relatively free flow of liquid in a downward direction through the check valve assembly 51.

A lower surface 75 of the radially outwardly extending flange portion 63 of the tubular member 59 defines a secondary seat or backup seat for engagement by the inwardly extending thin pliable lip 74 of the primary seat member 70 to insure a high pressure seal against backflow of fluid in the upward direction.

The check valve assembly 51 includes a spherical valve member loosely retained in the housing 55 and, in the absence of an upward pressure, supported on a plurality of ribs 81 formed internally to the housing 55. The movable valve member 80 may be formed of a styrene copolymer or similar lightweight material and includes a generally solid lower portion 83 and a hollow upper portion 84 molded as separate halves. The two halves may be solvent welded to form a buoyant, unbalanced, ball-like valve member 80 movable within the housing 55 in a predetermined orientation so that a surface free of flash lines is always oriented for engagement with the lip 74 of the resilient seat member 70.

As previously indicated, the ball valve member 80 is buoyant and upon a rise of liquid in the conduit 45 leading from the pump 42 to the tub outlet 53, such as occurring at termination of a pump-out operation, will rise to engage the lip 74 of the primary valve seat 70 as shownin FIG. 4. This seal is effected by relatively low pressures such as are present with a rising liquid level acting on the valve member 80. The seal is sufficient to prevent passage of liquid beyond the seal member 70 so that used washing liquid is not returned into the outer tub 29 upon cessation of the pumping action at termination of the extraction operation.

In a construction as shown in FIG. 1 wherein operation of the pump 42 in an opposite direction tends to pump liquid toward the outer tub 29, it is important that a high pressure seal be effected to prevent the recirculation of liquid into the tub 29 under the force of the pump 42. Such a high pressure seal is effected in FIG. 5 wherein the higher pressure of the liquid in the backflow direction forces the movable valve ball member 80 further upwardly in the check valve so that the primary valve seat 70 flexes into engagement with the secondary valve seat comprising the lower surface 75 of the flange portion 63 so as to back up the primary seat for effecting a relatively high pressure fluid seal.

In a specific construction for the check valve, the primary valve seat 70 is formed of an ethylene propylene terpolymer having a durometer of approximately 40 Shore A and includes a lip portion approximately 0.020 inch in thickness and defining an opening approximately 7/8 inch diameter. The secondary valve seat defined by surface 75 is formed of similar material having a durometer of approximately 80 Shore A and a flange thickness of approximately five-sixteenths inch. In this specific example, the movable valve member is molded of a styrene acrylonitrile copolymer in approximately a one inch spherical ball. The movable valve member is operable to sealingly engage the primary seat at low pressures resulting from only the buoyancy force of water acting on the movable valve member when approximately half submerged in the rising liquid. I-Iigh pressures for this specific embodiment are in the general area of 5 psi and result from the reverse operation of the pump as is present during the washing portion of the cycle of operations.

This liquid control system is shown in a copending application entitled VALVE CONSTRUCTION filed on even date with this application by Gordon Jerry Davis and assigned to the assignee of the instant invention.

It is therefore seen that the liquid system disclosed herein including a one-way check valve in the conduit between the outer liquid containing tub and the pump permits advantageous operation by preventing the return of used washing liquid into the washing system following completion of the extraction operation and the termination of the pumping. This self-actuating system is reliable and permits the advantageous use of a bidirectional drive in a washing machine for achieving washing and extraction operations without employing auxiliary pumping systems or control systems.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and, although specific 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 the equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of this invention as defined in the following claims.

Iclaim:

1. In an apparatus for performing a washing operation and a liquid extraction operation, the combination comprising: means for effecting said washing and liquid extraction operations including an outer tub for containing washing liquid and having a drain outlet in a lower portion thereof, a perforate inner tub for containing articles to be washed in said liquid, and agitation means within said inner tub; means including a motor for operating said agitation means during said washing operation and for rotating said inner tub during said extraction operation; conduit means effectively connecting said drain outlet to an external drain; pump means associated with said conduit means and driven by said motor for effecting flow of washing liquid from said outer tub toward said extemal drain when said motor is operated as during said extraction operation; and one-way check valve means in said conduit means and operable for permitting generally free flow of liquid from said outer tub toward said external drain as during said extraction operation and responsive to residual liquid in said conduit means for preventing backflow of said residual liquid into said outer tub.

2. In an apparatus for performing a washing operation and a liquid extraction operation, the combination comprising: means for effecting said washing and liquid extraction operations including an outer tub for containing washing liquid and having a drain outlet in a lower portion thereof, a perforate inner tub for containing articles to be washed in said liquid, and agitation means within said inner tub; means including a reversible motor operable in a first direction for operating said agitation means during said washing operation and operable in a second direction for rotating said inner tub during said extraction operation; conduit means effectively connecting said drain outlet to an external drain; pump means associated with said conduit means and driven by said reversible motor for effecting a pressure head in the direction of said outer tub with said motor operating in said first direction as during said washing operation and for effecting a pressure head in the direction of said external drain when said motor is operated in said second direction as during said extraction operation; and one-way check valve means in said conduit means between said pump means and said outer tub for permitting generally free flow of liquid from said outer tub toward said external drain as during said extraction operation and for preventing flow of liquid into said outer tub from said conduit means.

3. In an apparatus for performing a washing operation and a liquid extraction operation as defined in claim 2 wherein said check valve means is disposed in said conduit means at the outlet of said outer tub and is responsive to movement of residual liquid in said conduit means toward said outer tub for operating to a closed condition to prevent flow of said residual liquid from said conduit means into said outer tub.

4. In an apparatus for performing a washing operation and a liquid extraction operation as defined in claim 2 wherein said check valve means defines a vertically oriented passageway nd wherein said check valve means includes a buoyant valve member responsive to reverse flow of liquid in said conduit means for operating to a closed condition to prevent flow of liquid into said outer tub from said conduit means.

5. In an apparatus for performing a washing operation and a liquid extraction operation as defined in claim 2 wherein said check valve means is operable for effecting a low pressure seal upon the cessation of pumping to prevent backflow of liquid into said outer tub from said conduit means and further operable for effecting a high pressure seal to prevent backflow of liquid into said outer tub from said conduit means during said washing operation.

6. In an apparatus for performing a washing operation and a liquid extraction operation, the combination comprising: means for effecting said washing and liquid extraction operations including an outer tub for containing washing liquid and having a drain outlet in a lower portion thereof, a perforate inner tub for containing articles to be washed in said liquid, and agitation means within said inner tub; means including a reversible motor operable in a first direction for operating said agitation means during said washing operation and operable in a second direction for rotating said inner tub during said extraction operation; conduit means effectively connecting said drain outlet to an external drain standpipe having an inlet located approximately the height of an upper portion of said outer tub;

bidirectional pump means associated with said conduit means and driven by said reversible motor for effecting a pressure head in the direction of said outer tub with said motor operating in said first direction as during said washing operation and for effecting flow of washing liquid from said outer tub toward said external drain when said motor is operated in said second direction as during said extraction operation; and selfactuating one-way check valve means in said conduit means adjacent said outlet and operable for permitting generally free flow of liquid from said outer tub toward said external drain standpipe as during said extraction operation and for preventing used washing liquid remaining in said conduit means from flowing into said outer tub after termination of said extraction operation.

7. In an apparatus for performing a washing operation and a liquid extraction operation as defined in claim 6 wherein said check valve means is responsive to backflow of liquid in said conduit means upon termination of said extraction operation for effecting a sealed condition to prevent residual liquid in said conduit means from flowing into said outer tub.

8. In an apparatus for performing a washing operation and a liquid extraction operation as defined in claim 6 wherein said check valve means is responsive to the relatively low urging force of liquid tending to backflow ll'l he direction toward said outer tub for effecting a sealed condition to prevent backflow into said outer tub upon termination of said extraction operation and wherein said check valve means is further responsive to the relatively higher urging force of pressure in said conduit with said motor operating in said first direction for maintaining said seal to prevent flow of liquid into said outer tub during said washing operation.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patan:No. 3,691,797 7 Datmi September 19, 1972 Inventor(s) Thomas R. Smith It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Abstract, line 8 "tube" should be tub Col. 1, line 42 After "machine" insert liquid Col. 1, line 44 Delete "operable in" Col. 1, line 65 "actuable" should be actuatable Col. 2, line 43 "actuable" should be actuatable Col. 2, lines 66 Delete "thru inclusive shown" & 67

C01. 3, lines 10 Delete "The main drive pulley 40 is drivingly & ll 99 with the main drive pulley 40."

Col. 3, line 14 "show" should be shown Col. 3, line 49 Delete "the" (first occurrence) and insertfrom Col. 3, line 59 After "of" insert the Col. 4, line 39 After "holes 67," insert to Col. 7, line 10 "nd" should be and Signed and sealed this 6th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-IOSO (10*69) USCOMM-DC 60376-P69 11 us. GOVERNMENT PRINTING OFFICE 190 0-- 368-134

Claims

1. In an apparatus for performing a washing operation and a liquid extraction operation, the combination comprising: means for effecting said washing and liquid extraction operations including an outer tub for containing washing liquid and having a drain outlet in a lower portion thereof, a perforate inner tub for containing articles to be washed in said liquid, and agitation means within said inner tub; means including a motor for operating said agitation means during said washing operation and for rotating said inner tub during said extraction operation; conduit means effectively connecting said drain outlet to an external drain; pump means associated with said conduit means and driven by said motor for effecting flow of washing liquid from said outer tub toward said external drain when said motor is operated as during said extraction operation; and one-way check valve means in said conduit means and operable for permitting generally free flow of liquid from said outer tub toward said external drain as during said extraction operation and responsive to residual liquid in said conduit means for preventing backflow of said residual liquid into said outer tub.

6. In an apparatus for performing a washing operation and a liquid extraction operation, the combination comprising: means for effecting said washing and liquid extraction operations including an outer tub for containing washing liquid and having a drain outlet in a lower portion thereof, a perforate inner tub for containing articles to be washed in said liquid, and agitation means within said inner tub; means including a reversible motor operable in a first direction for operating said agitation means during said washing operation and operable in a second direction for rotating said inner tub during said extraction operation; conduit means effectively connecting said drain outlet to an external drain standpipe having an inlet located approximately the height of an upper portion of said outer tub; bidirectional pump means associated with said conduit means and driven by said reversible motor for effecting a pressure head in the direction of said outer tub with said motor operating in said first direction as during said washing operation and for effecting flow of washing liquid from said outer tub toward said external drain when said motor is operated in said second direction as during said extraction operation; and self-actuating one-way check valve means in said conduit means adjacent said outlet and operable for permitting generally free flow of liquid from said outer tub toward said external drain standpipe as during said extraction operation and for preventing used washing liquid remaining in said conduit means from flowing into said outer tub after termination of said extraction operation.

8. In an apparatus for performing a washing operAtion and a liquid extraction operation as defined in claim 6 wherein said check valve means is responsive to the relatively low urging force of liquid tending to backflow in the direction toward said outer tub for effecting a sealed condition to prevent backflow into said outer tub upon termination of said extraction operation and wherein said check valve means is further responsive to the relatively higher urging force of pressure in said conduit with said motor operating in said first direction for maintaining said seal to prevent flow of liquid into said outer tub during said washing operation.