U.S. patent application number 11/574947 was filed with the patent office on 2008-03-27 for method for operating a washing machine.
This patent application is currently assigned to MIELE & CIE. KG. Invention is credited to Andreas Bextermoller, Dirk Dahlke, Volker Karweg.
Application Number | 20080072383 11/574947 |
Document ID | / |
Family ID | 34485705 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080072383 |
Kind Code |
A1 |
Bextermoller; Andreas ; et
al. |
March 27, 2008 |
Method for Operating a Washing Machine
Abstract
A method for operating a washing machine includes cyclically
reading values detected by a sensor for detecting a weight of a
washing assembly container of the washing machine. At least a last
read value of the read values is stored. A rest position of the
container is determined as long as the read values are below a
predetermined tolerance level. The control unit is activated when a
read value of the read values exceeds the predetermined tolerance
level.
Inventors: |
Bextermoller; Andreas;
(Melle, DE) ; Dahlke; Dirk; (Rheda-Wiedenbruck,
DE) ; Karweg; Volker; (Gutersloh, DE) |
Correspondence
Address: |
DARBY & DARBY P.C.
P.O. BOX 770, Church Street Station
New York
NY
10008-0770
US
|
Assignee: |
MIELE & CIE. KG
Guetersloh
DE
|
Family ID: |
34485705 |
Appl. No.: |
11/574947 |
Filed: |
September 5, 2005 |
PCT Filed: |
September 5, 2005 |
PCT NO: |
PCT/EP05/09509 |
371 Date: |
March 8, 2007 |
Current U.S.
Class: |
8/159 |
Current CPC
Class: |
D06F 2204/084 20130101;
D06F 39/081 20130101; D06F 34/18 20200201 |
Class at
Publication: |
8/159 |
International
Class: |
D06F 33/02 20060101
D06F033/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2004 |
DE |
10 2004 043 838.2 |
Claims
1-6. (canceled)
7. A method for operating a washing machine comprising a housing, a
washing assembly resiliently mounted in the housing and including a
container for receiving laundry and/or wash liquid, a control
panel, a control unit including at least one evaluation unit and a
memory, and a sensor for detecting a weight of the container, the
method comprising: cyclically reading values detected by the
sensor; storing at least a last read value of the read values;
determining a rest position of the container as long as the read
values are below a predetermined tolerance level; and activating
the control unit when a read value of the read values exceeds the
predetermined tolerance level.
8. The method as recited in claim 7 wherein the sensor includes a
displacement sensor.
9. The method as recited in claim 7 further comprising evaluating,
using the evaluation unit, a variation over time of changes in the
read values.
10. The method as recited in claim 8 further comprising evaluating,
using the evaluation unit, a variation over time of changes in the
read values.
11. The method as recited in claim 7 further comprising
determining, using the evaluation unit, a laundry weight based on a
final read value of the read values minus a value of the read
values for a rest position of the washing assembly.
12. The method as recited in claim 7 further comprising detecting,
using the evaluation unit, a fault, and activating, using the
evaluation unit, an alarm function, when a change in the read
values is below a second predetermined level and at least a last
read value of the read values exceeds a predetermined
threshold.
13. The method as recited in claim 12 wherein the fault includes an
improper entry of water.
14. The method as recited in claim 12 wherein the alarm function
includes at least one of a visual alarm indication, an audible
alarm indication, an alarm signaling via a communication system,
and an activation of a drain pump for removing suds.
Description
CROSS REFERENCE TO PRIOR APPLICATION
[0001] This is a U.S. national phase application under 35 U.S.C.
.sctn.371 of International Patent Application No.
PCT/EP2005/009509, filed Sep. 5, 2005, and claims benefit of German
Patent Application No. 10 2004 043 838.2, filed Sep. 8, 2004, which
is incorporated by reference herein. The International Application
was published in German on Mar. 16, 2006 as WO 2006/027183 A1 under
PCT Article 21(2).
[0002] The present invention relates to a method for operating a
washing machine and, in particular, to a method for a
program-controlled washing machine including a housing, a washing
assembly which is resiliently mounted in the housing and includes a
container for receiving laundry and/or wash liquid, the washing
machine further including a control panel and a control unit, the
control unit including at least one evaluation unit and a memory,
and the washing machine further including a sensor for detecting
the weight of the container.
BACKGROUND
[0003] German Utility Model Patent DE 298 12 393 describes a
washing machine including an oscillating washing assembly and a
force or pressure sensor provided on one of the suspension means of
the washing assembly for weight measurement purposes.
[0004] Another way of detecting the weight is disclosed in German
Laid Open Application DE 199 60 847 A1 and consists in providing a
strain gauge in the area of the rear wall of the suds container,
said strain gauge changing its electrical properties in response to
twisting of the holding members of the drum. The load condition of
the drum is thus determined based on the measured electrical
properties. In this method, the measurement is limited to the
content of the drum, so that it is not possible to measure the
weight of the wash liquid contained in the suds container.
[0005] German Laid Open Application DE 101 22 749 A1 describes a
washing machine which includes an oscillating washing assembly and
uses a displacement sensor to determine the weight. The washing
assembly is suspendedly mounted to the housing by means of springs,
and uses shock absorbers in the form of friction dampers, or
so-called spring plunger-type friction dampers. Also described
therein is a displacement sensor which is incorporated in a spring
plunger-type friction damper.
[0006] In all of the known systems for detecting the weight of the
laundry, it is mandatory, first of all, that the control unit, or
the detection means, be activated prior to introducing the laundry
into the washing drum, said activation generally being effected by
turning on the washing machine. However, if the laundry is
introduced into the washing drum prior to turning on the washing
machine, it is no longer possible to automatically detect the
laundry weight because the rest position of the washing drum, or of
the washing assembly, is not known.
[0007] In this regard, German Laid Open Application DE 102 36 937
A1 describes a way to automatically activate or turn on the control
panel of a washing machine. In that patent, the control panel is
activated by an integrated motion detector. The indicators located
in the control panel or the control unit are not activated or
turned on before a person is present in the area covered by the
motion sensor. However, the use of a motion sensor is very complex
and sensitive to unwanted activation.
[0008] Another way of detecting the laundry weight in washing
machines is described in German Patent DE 198 47 487 C2. In that
patent, both the recovery behavior of friction-based shock
absorbers and the different user habits are taken into account. The
rest position of the washing assembly prior to introducing the
laundry for a new wash cycle is determined after turning on the
washing machine and taken into account in the determination of the
weight after the laundry is introduced. In the event of erroneous
control inputs, or when laundry is introduced prior to turning on
the washing machine, the detection unit detects a value outside the
tolerance range for the rest position, and a rest position
determined in the last wash cycle is taken into account by the
detection unit in this weight determination procedure. This has the
disadvantage that if the user has this habit, a slow change in the
rest position resulting from wear of the suspension means or shock
absorbers is not detected and therefore not taken into account in
the determination of the weight.
SUMMARY
[0009] It is therefore an object of the present invention, on the
one hand, to enable the weight of the laundry and/or of the loaded
container to be detected reliably and accurately, while taking into
account different user habits and, on the other hand, to enable
disturbances to be detected before the program is started.
[0010] The present invention provides a method for operating a
washing machine. The washing machine includes a housing, a washing
assembly resiliently mounted in the housing and including a
container for receiving laundry and/or wash liquid, a control
panel, a control unit including at least one evaluation unit and a
memory, and a sensor for detecting a weight of the container. The
method includes: cyclically reading values detected by the
sensor;
[0011] storing at least a last read value of the read values;
[0012] determining a rest position of the container as long as the
read values are below a predetermined tolerance level; and
[0013] activating the control unit when a read value of the read
values exceeds the predetermined tolerance level.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] An exemplary embodiment of the present invention is shown in
the drawings in a schematic way and will be described in more
detail below. In the drawings,
[0015] FIG. 1a schematically illustrates the arrangement of the
washing assembly in a housing;
[0016] FIG. 1b schematically illustrates the position of the
washing assembly in a loaded condition;
[0017] FIG. 2 shows, by way of example, a state diagram for the
control;
[0018] FIG. 3a shows a time history for an introduction of
laundry;
[0019] FIG. 3b shows a time history for an improper entry of
water.
DETAILED DESCRIPTION
[0020] In addition to a reliable and accurate determination of the
laundry weight while detecting and accounting for disturbances,
another advantage made possible by the present invention is the
reliable activation of the control panel and/or the control unit.
An example of a disturbance to be mentioned is the recovery
behavior of friction-based shock absorbers. Because of the
frictional behavior, the unit to be measured reaches a slightly
different position each time it is reset when the decelerating
effect of the friction-based shock absorber dominates over the
restoring force of the springs used for the resilient suspension of
the washing assembly. After a spin-dry cycle at the end of a wash
program, the rest position may differ considerably because of the
imbalance-induced vibrations of the washing assembly or of the
container. Another disturbance is an improper entry of water into
the container, for example, into the suds container.
[0021] In order to achieve these advantages, the rest position of
the container or washing assembly receiving the laundry and/or the
wash liquid is reliably determined shortly before each wash cycle.
This provides the advantage that changes in the weight of the
container are detected and evaluated before the wash program
selected by the user is activated. To this end, a control unit
including an evaluation unit and a memory, and a sensor for
detecting the weight are provided in the washing machine. The
values detected by the sensor are cyclically read in, and at least
the last read value is stored. This allows the evaluation unit to
compare a read value to the last value read or a plurality of
values. As long as the values read do not change or fall below a
predetermined tolerance level, the rest position or home position
of the container, generally the washing assembly, will be
determined. When a read value exceeds the predetermined tolerance
level for a change in value, the control unit will be
activated.
[0022] In a suitable embodiment, a displacement sensor is used for
detecting the weight, said displacement sensor generally being
disposed between the washing assembly and the housing. The laundry
weight can also be detected using other methods, such as by
pressure measurement or twist measurement.
[0023] In another advantageous embodiment, the variation with time
of a plurality of stored values is used for evaluation.
[0024] In order to obtain an accurate result, the displacement
sensor is read at least one more time after the control unit has
been activated, and from this value, which is read under load, is
subtracted the value that was detected for the rest position in the
sleep mode, and the result of this calculation is used as the
weight of the laundry. In order to minimize inaccuracies in the
value of the rest position, it is possible to insert delays between
the individual sensor value acquisition cycles, or to perform a
plausibility check based on a plurality of consecutively acquired
values. This means, for example, that a constant value is assumed
to be the rest position only after several successive measurements
have been made.
[0025] Since the method of the present invention detects and
evaluates the weight of the washing assembly or of the container
for receiving laundry and/or wash liquid, the method is suitable
for all washing machines that have a resiliently suspended washing
assembly, in particular a suds container, a washing drum rotating
therein, and the drive components of said washing drum; or a tub,
an agitator disposed therein, and the drive components of said
agitator; or a water-filled rotating drum and its drive components.
Due to the recovery behavior of the friction dampers, the
determined or assumed rest position may be within a defined
tolerance range.
[0026] The determination of the rest position is carried out during
the time in which the control panel and the control unit are
inactive, i.e., when all controls are inactive and the indicators,
such as indicator lights and displays, are turned off. During this
time, the control unit is inactive, which is hereinafter referred
to as "sleep mode", except for the cyclic acquisition and storage
of the values from the displacement sensor. This sleep mode is
particularly energy-efficient because only part of the control unit
or evaluation unit is active.
[0027] In an advantageous embodiment, the cyclic detection of the
weight of the container or washing assembly makes it possible to
detect faults, in particular an improper entry of water in the
sleep mode, i.e., while the washing machine is turned off or the
control unit and the control panel are inactive. For this purpose,
the dynamic behavior of the values read from the sensor is taken
into account. If the change of a read value as compared to the
previously stored value is below a predetermined level, this is
evaluated as a slow increase in weight resulting from an improper
entry of water. Once a further predetermined threshold is exceeded,
the evaluation unit will detect a fault and activate an alarm
function. Possible alarm functions advantageously include visual
alarm indications, audible alarm indications, or alarm signaling
via communication systems such as the Internet, mobile telephone,
and/or activation of the drain pump for removing suds.
[0028] As schematically shown in FIG. 1, washing assembly 2 is
resiliently mounted by springs 3, in a suspended fashion, to
housing 1, or to load-bearing parts (not further described) of the
housing. The washing assembly essentially includes a suds
container, a washing drum rotatably mounted in said suds container,
and the drive system, for example, a motor with a belt drive. Shock
absorbers 4 are used to prevent vibrations in the event of an
imbalance of the rotating drum. A displacement sensor 6 is used to
detect imbalance and, in addition, the load condition of the drum.
The values output by or read from displacement sensor 6 are
preferably evaluated in a control unit 5 which is disposed in
washing machine 29 and includes at least one evaluation unit and a
memory. The washing assembly 2 schematically shown in FIG. 1a is in
an unloaded condition, while the schematic view of FIG. 1b shows
washing assembly 2 in a loaded condition. Here it can clearly be
seen that washing assembly 2 is in a appreciably lower position as
compared to its rest position 8, so that displacement sensor 6
outputs a value that corresponds to a high weight of washing
assembly 2. Control unit 5 includes an evaluation unit which reads
each value of displacement sensor 6 via signal connection 7 and
interprets a value change corresponding to a change in the weight
of washing assembly 2 as the weight of the laundry. In the process,
the evaluation unit distinguishes the dynamic behavior of the
weight change, one function being the automatic activation of
washing machine 29 or control unit 5.
[0029] As illustrated in a state diagram in FIG. 2, no state
transition occurs as long as the detected value s(t) does not
differ from one or more values s(t-n) detected at previous points
in time, or is below a predetermined tolerance limit 18, i.e.,
control unit 2 remains in sleep mode 9. The state diagram of FIG. 2
further shows that control unit 2 is switched from sleep mode 9 to
active mode 10 as a function of the values s(t) 14 output by
displacement sensor 6, in particular when a currently detected
value s(t) of one or more values s(t-n) detected at previous points
in time is greater than a predetermined tolerance limit, or
corresponds to a higher weight of washing assembly 2; thus, a state
change 11 takes place. In active mode 10, for example, the control
panel is activated along with the indicators, and control unit 5 is
made ready to receive control inputs. It should be noted here that
in the sleep mode, the energy consumption of the entire washing
machine is appreciably below an established threshold for a
relevant level of energy consumption in the to-be-provided sleep
mode, generally also referred to as "standby". A transition change
13 from active mode 10 to sleep mode 9 can occur depending on the
progression of the wash program or other actions of the user, such
as terminating the wash program, opening the door and removing the
laundry.
[0030] FIG. 3a shows, by way of example, the dynamic behavior over
time for an introduction of laundry, and the state changes
resulting therefrom. The value of displacement sensor 6 is
cyclically read at intervals in time. The instants at which the
displacement sensor is read out are exemplarily indicated on time
axis t by 1 through 15. The read, low value 15 remains unchanged
until instant 10. This read value 15 is stored as a reference for
the rest position 15 or home position of the washing assembly,
preferably in a memory within control unit 5. At instant 11, the
read value exceeds a predetermined tolerance level 18, whereupon
the evaluation unit in control unit 5 detects an introduction of
laundry at state 16 and switches the control unit 5 and the control
panel from sleep mode 9 to active mode 10, as illustrated by
transition arrow 19. When the final value 17 is reached, this value
17 is taken for determining the laundry weight. The weight of the
laundry is determined based on this value 17 minus the previously
determined value for rest position 15 of washing assembly 2.
[0031] FIG. 3b illustrates another way in which the evaluation
unit, based on the cyclic acquisition of the value of a
displacement sensor 6, can detect an improper entry of water into
the washing assembly and subsequently activate an alarm function
26. An improper entry of water would cause a slow increase in the
weight of the suds container and, consequently, of washing assembly
2. This would lead to changes in value over time, each individual
detected change in value being below a predetermined level 28. The
evaluation unit will only detect a fault if the detected change in
value is below a predetermined level 28 and the last detected value
exceeds a predetermined absolute threshold 20. At instants 1 and 2,
no change 20 is detected in the read and/or stored values 15. At
the instants t=3 through t=5, a change 20 is detected in the read
and/or stored values, but the values are below a threshold 20 for
fault detection. At instants 6 through 7, an increased small change
21 is detected in the read and/or stored values, said change being
just at the threshold 20 for fault detection. At instants 8 through
10, an increased change 22 is detected in the read and/or stored
value, which are above the threshold 20 for fault detection and
continue to increase 23 after the instant 10. Since each change in
value 27 is below the predetermined level 28, the variation with
time of the value change, together with the exceeding of threshold
20, is interpreted by evaluation unit 5 as an improper entry of
water, whereupon the evaluation unit can activate an alarm function
26. As illustrated in FIG. 1a, alarm function 26 may be an audible
alarm indication 31, visual alarm indication 30, or alarm signals
transmitted via data-transmission media 32, or activation of drain
pump 33 for removing suds, in order to prevent water damage by
water leaking from washing assembly 2.
[0032] The present invention is not limited to the embodiments
described herein; reference should be had to the appended
claims.
LIST OF REFERENCE NUMERALS
[0033] 1 housing [0034] 2 washing assembly [0035] 3 spring [0036] 4
shock absorber [0037] 5 control panel and/or control unit [0038] 6
displacement sensor [0039] 7 signal connection [0040] 8 rest
position [0041] 9 sleep mode [0042] 10 active mode [0043] 11
transition to the active mode [0044] 12 continuance of the sleep
mode [0045] 13 transition to the sleep mode [0046] 14 reading cycle
[0047] 15 displacement sensor in the rest position [0048] 16
displacement sensor detects introduction of laundry [0049] 17
displacement sensor detects final laundry weight [0050] 18
tolerance level or threshold for load detection [0051] 19
transition arrow [0052] 20 threshold for fault detection [0053] 21
value<threshold [0054] 22 value=threshold [0055] 23
value>threshold [0056] 24 value>>threshold [0057] 25 alarm
function deactivated [0058] 26 alarm function activated [0059] 27
change in value [0060] 28 predetermined level for the change in
value [0061] 29 washing machine [0062] 30 visual alarm function
[0063] 31 audible alarm function [0064] 32 communication system
[0065] 33 drain pump for removing suds
* * * * *