Dec. 26, 1967
'
‘R. H. HAAS
I
3,359,766
AUTOMATIC FLUID LEVEL DEVICE
Filed Dec. 19, 1966
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AGITATION
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Ronald H 7252 (15
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United States Patent 0 " lC€
3,359,766
Patented Dec. 26, 1967
1
2
3,359,766
It is a further object of the present invention to pro
vide a washing machine with ‘an automatic liquid level
AUTQMATIC FLUID LEVEL DEVICE
Ronald H. Haas, Lansing, Mich, assignor to Borg-Warner
Corporation, Chicago, 11]., a corporation of Illinois
Filed Dec. 19, 1966, Ser. No. 602,694
10 Claims. (Cl. 68-207)
control which a?ords substantial savings in water, de
tergent and other additives by supplying only the neces
sary amount of liquid required by each particular load.
It is a further object of the present invention to pro
vide an automatic liquid level control which can be used
to safeguard the motor and drive line components of a
This invention relates to laundry apparatus and more
washing machine by automatically supplying the proper
particularly to automatic liquid level control means
therefor.
10 amount of liquid for a particular load to avoid an exces
sive agitator torque.
One of the problems of the present automatic wash
This invention consists of the novel constructions, ar
ing machine operation is the selection of the proper water
rangements and devices to be hereinafter described and
level during agitation. One method presently used is to
claimed for carrying out the ‘above stated objects and
?ll the tub to any number of predetermined levels by
means of a preposition water level switch.
such other objects as well be apparent from the follow
ing description of preferred forms of the invention, illus
Another method is to ?ll anywhere between ‘a pre
determined maximum and minimum by an in?nite control
trated with reference to the accompanying drawings
water level switch.
wherein:
1
FIGURE 1 is 'a schematic view of a washing machine
Still a third method is to use a timer to admit liquid
for a pre-set time interval again to ?ll to one of a series 20 and liquid level control means therefor; and
of predetermined levels.
The problem posed by the present systems is that they
a?ord a possibility of operator error, permitting Waste
of hot water, detergent and other additives or alterna
tively allowing damaging overload to all drive line com
ponents. If the water level is set for more water than is
actually required, the housewife uses ‘an excess amount of
water and detergent and any other additive whose strength
is based on its addition to a proportionate amount of
water. If the water level is set too low for the particular
load, the clothes pack against the agitator ‘and overload
the electric motor as well as all drive line components
which results in premature failures.
The decision as to which water level should be used
FIGURE 2 is a plan view in schematic of the ?uid
' pressure sensing switch including a circuit diagram of
means cooperating with the pressure sensing switch.
Although this invention is applicable to any type of
machine for the liquid treatment of materials, for pur
poses of illustration the automatic liquid level control is
shown in connection with an automatic washing machine
of the vertical axis type utilizing an oscillatory agitator.
This arrangement is purely for purposes of illustration
of the inherent advantage of the invention and should
not be considered as a limitation of the scope of its
‘application.
A washing machine 10 is shown in FIGURE 1 with
is not an easy one because of the variables involved
a support structure 11 housing a container 12 into which
' are deposited the materials to be laundered plus the ap
water level control system which removes the chance of
hausts ?uid to a sump 21 through a second ?uid conduit
propriate cleansing agents. An agitator 13 is mounted
e.g., size of load, type of load, etc. It is obvious that
within‘ the container 12 for actuation by ?uid drive sys
10 pounds of towels will require more water than 10
tem 14. The ?uid drive system 14 includes an electric
pounds of hankerchiefs to maintain the same agitator
motor 17 connected to drive a hydraulic pump 18 which
torque.
The present invention overcomes these objections by 40 supplies ?uid pressure to a hydraulic motor 19 by means
of a ?rst ?uid conduit 20. The hydraulic motor 19 ex
providing a washing machine incorporating an automatic
22. Fluid is communicated from the sump 21 to hydrau
error by eliminating the judgment factor of the operator.
lic pump 18 through a third ?uid conduit 23. The hy
With the advent of hydrostatic transmissions in auto
matic washing machines, it is possible to sense the torque 45 draulic motor 19 is operable associated with the agitator
13 to impart to it an oscillatory motion.
of the wash load through the agitator motor ?uid pres
sure. The pressure at the motor in the ?uid drive system
increases as the agitator torque increases.
The present invention utilizes a simple pressure sensing
switch associated with the ?uid drive system set for the
A ?uid pressure sensing switch 24 is shown in ?uid
communication with the ?rst ?uid conduit 21} and senses
the ?uid pressure at the hydraulic motor 13 which is a
sure level is exceeded a water ?ll valve is turned on there
function of the torque of the Wash load.
A solenoid controlled ?ll valve 25 similar to those
commonly known in the art, is shown connected to a hot
by adding liquid until the torque decreases to the desired
operating level. At this time the pressure sensing switch
water source 26 and a cold water source 27. The ?ll
valve acts to communicate either hot water or cold water
circuit would open and shut off the water ?ll valve and
or, mixing both, warm water to the container 12 through
?uid conduit 28.
maximum desired agitator torque. When the pre-set pres
thereby operate the washing machine at its optimum water
level. This would supply the correct water level to op
erate the washing machine e?iciently and economically.
Minimum and maximum water level switches are in
A maximum liquid level switch 31 of the air column
type is shown in FIGURE 1 but any of several common
types may be used. A conduit 32 containing air is in ?uid
corporated respectively to provide a minimum pre-?ll 60 communication with the container 12 and a diaphragm
type pressure switch 33 such that as the liquid level in the
container 12 increases, the air pressure in the conduit
32 increases until the predetermined maximum level is
reached and the pressure in the conduit 32 is su?icient
in special circumstances, for example, heavily soiled
clothes. This will allow the water level to‘ be set any 65 to trip the diaphragm-type switch 33.
FIGURE 2 shows the ?uid pressure sensing switch 24
where between the automatic shut-off and full water level
including a housing 34 de?ning a ?rst bore 35 and a sec
for any load.
ond bore 38 concentric with the ?rst bore 35 and of
It is, therefore, an object of the present invention to
prior to agitation and a liquid shut-off to prevent over
?ow. A manual override switch is further included to
allow the operator to wash a light load with full water
slightly smaller diameter. A spool valve 39 is adapted to
provide a washing machine having an automatic liquid
level control to automatically provide the correct amount 70 slide axially within the ?rst bore 35 when acted on by
the hydraulic motor ?uid pressure. Detent means 40 are
of liquid necessary for each individual load.
3,859,766
6
a ?uid drive system connected to said agitation means in
cluding a source of ?uid pressure, the ?uid pressure in said
pressure from said hydraulic pump and to drive said
drive system increasing as the torque required to drive
agitator, the ?uid pressure in said drive system increasing
said agitation means increases; means associated with
as the torque required to drive said agitator increases.
said drive system for sensing said ?uid pressure; means
4. A machine for liquid treatment of materials as in
for introducing an additional amount of liquid into said
claim 2 in which said means for sensing the ?uid drive
container in response to said ?uid pressure.
pressure consists of a pressure sensing switch, including:
8. A Washing machine as in claim 7 in which said
valve means adapted to be actuated by said ?uid pressure;
‘means for introducing an additional amount of liquid into
biasing means adapted to urge said valve means against
said ?uid pressure; a conductive member associated with 10 said container in response to said ?uid pressure includes;
a liquid supply source; an electric circuit; a source of
said valve means adapted to move in response to move
electrical
energy connected to said electric circuit; elec—
ment of said valve means.
trically controlled valve means in said circuit associated
5. A machine for liquid treatment of materials as in
with said liquid supply source to introduce liquid into
claim 2 in which said means for sensing ?uid pressure
includes: a ?uid connection between said ?uid drive sys 15 said container when energized; a normally open electrical
switch in said circuit adapted to be contacted by said
tem and said means for sensing ?uid pressure; an ori?ce
a ?uid source; a hydraulic motor adapted to receive ?uid
pressure sensing means thereby activating said electri
in said ?uid connection whereby said ori?ce acts to damp
cally controlled valve means.
9. A Washing machine as in claim 7 including means
said ori?ce responsive to said ?uid pressure whereby said 20 for introducing a predetermined minimum amount of
any pressure pulsations and communicates only an aver
age pressure level; means in ?uid communication with
liquid into said container.
means are adapted to move in response to an increase or
10. A washing machine as in claim 7 including means
decrease in said ?uid pressure; a conductive member op
limiting said additional amount of liquid introduced into
erably associated with said pressure responsive means
and adapted to move in response to movement of said
said container to a predetermined maximum value.
25
pressure responsive means.
References Cited
6. A machine for liquid treatment of materials as in
claim 2 in which said means for sensing ?uid pressure
UNITED STATES PATENTS
consists of a pressure sensing switch, including: a housing
2,911,811 11/1959 Clark ______________ __ 68-12
de?ning a ?rst bore; valve means adapted to slide Within
2,955,448 10/1960 Olthuis _____________ __ 68‘—12
30
said bore in response to said ?uid pressure; detent means
3,065,618 11/1962 Cobb et al. _________ __ 68-42
within said housing adapted to engage said valve means;
3,106,081 10/ 1963‘ Mitchell ___________ __ 68—12
biasing means adapted to urge said valve means against
3,195,327
7/1965 Cobb ______________ __ 68-42
said ?uid pressure; a conductive member associated with
said valve means adapted to move in response to move
ment of said valve means.
7. A washing machine including: a container for ma
terials to be washed; agitation means in said container;
35
3,242,703
3,316,569
3/1966
5/1967
Brundage __________ __ 68—-d23
Brenner et al. _____ .._ 68-412 X
WILLIAM 1. PRICE, Primary Examiner.