U.S. patent application number 12/031564 was filed with the patent office on 2008-08-21 for control method for commercial washing machine.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Ji An JEONG.
Application Number | 20080196172 12/031564 |
Document ID | / |
Family ID | 39479710 |
Filed Date | 2008-08-21 |
United States Patent
Application |
20080196172 |
Kind Code |
A1 |
JEONG; Ji An |
August 21, 2008 |
CONTROL METHOD FOR COMMERCIAL WASHING MACHINE
Abstract
A control method for a commercial washing machine that is
capable of reducing washing time unnecessarily wasted during a
washing or rinsing operation in which a water supplying process, a
washing or rinsing process, a draining process, and a spin-drying
process are repeatedly performed according to a corresponding
course, the washing or rinsing operation being carried out before a
main spin-drying operation, thereby improving the economy of the
commercial washing machine is disclosed. The control method
includes detecting the amount of laundry after the completion of a
draining process, detecting the eccentricity of a drum and
determining whether the eccentricity of the drum has been resolved
by rotating the drum at an eccentricity detecting RPM after the
step of detecting the amount of laundry, and performing a spin
drying process with the drum being rotated at different RPMs
depending upon the determination as to whether the eccentricity of
the drum has been resolved.
Inventors: |
JEONG; Ji An; (Changwon-Si,
KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
LG Electronics Inc.
Seoul
KR
|
Family ID: |
39479710 |
Appl. No.: |
12/031564 |
Filed: |
February 14, 2008 |
Current U.S.
Class: |
8/159 |
Current CPC
Class: |
D06F 37/203 20130101;
D06F 33/00 20130101; D06F 35/007 20130101; D06F 34/18 20200201 |
Class at
Publication: |
8/159 |
International
Class: |
D06F 33/00 20060101
D06F033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 15, 2007 |
KR |
10-2007-0016129 |
Claims
1. A control method for a commercial washing machine, performed
during a washing or rinsing operation in which the corresponding
operation is carried out using wash water and the wash water is
discharged, the control method comprising: detecting the amount of
laundry received in a drum; detecting the eccentricity of the drum
and determining whether the eccentricity of the drum has been
resolved, during the rotation of the drum, by rotating the drum for
a predetermined period of time such that the laundry can be moved;
and performing a spin-drying process with the drum being rotated at
different rotation speeds depending upon the determination as to
whether the eccentricity of the drum has been resolved.
2. The control method according to claim 1, wherein the step of
performing the spin-drying process is carried out during the
washing operation or the rinsing operation.
3. The control method according to claim 2, wherein the step of
detecting the eccentricity of the drum includes rotating the drum
at a predetermined rotation speed for the predetermined period of
time such that the laundry can be moved, and determining whether
the eccentric rotation of the drum has been resolved.
4. The control method according to claim 3, wherein the
determination as to whether the eccentric rotation of the drum has
been resolved is made by detecting the eccentricity amount of the
drum and determining whether the detected eccentricity amount is
less than a predetermined reference eccentricity amount.
5. The control method according to claim 4, wherein, when it is
determined at the step of detecting the eccentricity of the drum
that the eccentricity of the drum has not been resolved, the step
of performing the spin-drying process is carried out with the drum
being rotated at an informal spin-drying RPM for a predetermined
period of time.
6. The control method according to claim 5, wherein the informal
spin-drying RPM is more than the RPM at which the drum is rotated
at the step of detecting the eccentricity of the laundry.
7. The control method according to claim 5, wherein the informal
spin-drying RPM is the same as the RPM at which the drum is rotated
at the step of detecting the eccentricity of the laundry.
8. The control method according to claim 5, wherein, when it is
determined at the step of detecting the eccentricity of the drum
that the eccentricity of the drum has been resolved, the step of
performing the spin-drying process is carried out with the drum
being rotated at a formal spin-drying RPM.
9. The control method according to claim 8, wherein the formal
spin-drying RPM is more than the RPM at which the drum is rotated
at the step of detecting the eccentricity of the laundry.
10. The control method according to claim 8, wherein the formal
spin-drying RPM is more than the informal spin-drying RPM.
11. The control method according to claim 4, wherein the step of
detecting the eccentricity of the drum is carried out a
predetermined number of times until it is determined that the
detected eccentricity amount is less than the reference
eccentricity amount.
12. The control method according to claim 11, wherein the
predetermined number of times at the step of detecting the
eccentricity of the drum is limited to 5 times or less.
13. The control method according to claim 11, wherein, when it is
determined at the step of detecting the eccentricity of the drum
that the detected eccentricity amount is less than the reference
eccentricity amount, the step of detecting the eccentricity of the
drum is terminated, and the step of performing the spin-drying
process is carried out with the drum being rotated at a formal
spin-drying RPM.
14. The control method according to claim 5, wherein the
predetermined period of time at the step of performing the
spin-drying process is between 10 seconds and 30 seconds.
15. The control method according to claim 3, wherein the
predetermined rotation speed at the step of detecting the
eccentricity of the drum is between 100 rpm and 120 rpm.
16. The control method according to claim 1, further comprising:
performing a water-supplying process after the step of performing
the spin-drying process.
17. A control method for a commercial washing machine, performed
during a washing or rinsing operation in which a water supplying
process, a draining process, and a spin-drying process are
repeatedly performed, the washing or rinsing operation being
carried out before a final spin-drying operation, the control
method comprising: detecting the amount of laundry received in a
drum after the draining process is completed; detecting the
eccentricity of the drum and determining whether the drum is
rotated in an eccentric fashion by rotating the drum for a
predetermined period of time such that the laundry is
redistributed; and performing a spin-drying process, the step of
performing the spin-drying process including performing a formal
spin-drying process upon determination at the step of detecting the
eccentricity of the drum that the drum is not rotated in the
eccentric fashion and an informal spin-drying process upon
determination at the step of detecting the eccentricity of the drum
that the drum is rotated in the eccentric fashion.
18. The control method according to claim 17, wherein the rotation
RPM of the drum at the step of performing the informal spin-drying
process is equal to or greater than the rotation RPM of the drum at
the step of detecting the eccentricity of the drum and less than
the rotation RPM of the drum at the step of performing the formal
spin-drying process.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2007-0016129, filed on Feb. 15, 2007, which is
hereby incorporated by reference in its entirety as if fully set
forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a control method for a
commercial washing machine, and more particularly, to a control
method for a commercial washing machine that is capable of reducing
washing time unnecessarily wasted during a washing or rinsing
operation in which a water supplying process, a washing or rinsing
process, a draining process, and a spin-drying process are
repeatedly performed according to a corresponding course, the
washing or rinsing operation being carried out before a main
spin-drying operation.
[0004] 2. Discussion of the Related Art
[0005] Generally, a drum type washing machine is a machine that is
capable of washing laundry using frictional force generated by the
rotation of a washing drum, in which detergent, wash water, and
laundry are placed. Consequently, when laundry is washed using the
drum type washing machine, damage to the laundry is minimal, and
the laundry is not easily tangled. Furthermore, the laundry is
washed in a striking and rubbing fashion, and therefore, washing
effects are improved.
[0006] Generally, the drum type washing machine washes laundry
through a washing operation for removing contaminants from the
laundry using detergent, a rinsing operation for rinsing the
laundry using clean water, and a spin-drying operation for rotating
a drum at a high speed to finally remove wash water from the
laundry.
[0007] In both the washing operation and the rinsing operation, a
water supplying process and a draining process are carried out. In
addition, a spin-drying process for removing the wash water from
the laundry is carried out after the completion of the draining
process, such that a washing process and a rinsing process are
effectively performed.
[0008] During the spin-drying process, the drum is rotated at a
higher speed than during the washing process and the rinsing
process, and wash water is removed from the laundry by a
centrifugal force generated by the rotation of the drum. At this
time, if the laundry is eccentrically distributed in the drum, the
drum is rotated in an eccentric fashion, with the result that a
great load may be applied to a drive unit of the washing machine,
and noise may be generated by the drum. For this reason, a process
for uniformly rotating the drum at a speed lower than the rotation
speed during the spin-drying process to uniformly distribute the
laundry in the drum is generally carried out before the
commencement of the spin-drying process.
[0009] At this time, if the eccentricity of the laundry is not
resolved even after the laundry distributing process is carried
out, the laundry distributing process is repeatedly carried out. As
a result, the laundry distributing process is carried out even at
the spin-drying process included in both the washing operation and
the rinsing operation, whereby an excessive amount of time is
required to perform the washing operation or the rinsing
operation.
[0010] Especially for a commercial washing machine requiring a user
to pay laundry charges, when the washing of the laundry is not
completed within a predetermined period of time, extra laundry
charges must be paid. Furthermore, if the washing operation is
carried out at a Laundromat requiring a short washing cycle, time
incurred to complete one washing cycle is excessively increased,
with the result that an owner of the Laundromat, seeking to
maximize profits through a short washing cycle of the commercial
washing machine, may suffer substantial economic losses.
SUMMARY OF THE INVENTION
[0011] Accordingly, the present invention is directed to a control
method for a commercial washing machine that substantially obviates
one or more problems due to limitations and disadvantages of the
related art.
[0012] An object of the present invention is to provide a control
method for a commercial washing machine that is capable of reducing
washing time unnecessarily wasted during a washing operation and a
rinsing operation.
[0013] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0014] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, a control method for a commercial washing
machine, performed during a washing operation, a rinsing operation,
and a spin-drying operation, includes detecting the amount of
laundry after the completion of a draining process, detecting the
eccentricity of a drum and determining whether the eccentricity of
the drum has been resolved by rotating the drum at an eccentricity
detecting RPM after the step of detecting the amount of laundry,
and performing a spin-drying process with the drum being rotated at
different RPMs depending upon the determination as to whether the
eccentricity of the drum has been resolved.
[0015] Preferably, the step of performing a spin-drying process is
carried out during the washing operation or the rinsing
operation.
[0016] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiments of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0018] FIG. 1 is a sectional view illustrating a general drum type
washing machine;
[0019] FIG. 2 is a graph illustrating a procedure for entering a
spin-drying step after a draining step during a washing or rinsing
operation of the drum type washing machine;
[0020] FIGS. 3A to 3C are graphs illustrating processes carried out
after the completion of a draining step during a washing or rinsing
operation of a commercial washing machine according to the present
invention;
[0021] FIG. 4 is a flow chart illustrating a control method for a
commercial washing machine according to the present invention;
and
[0022] FIG. 5 is a flow chart illustrating a control method of a
laundry amount-detecting step according to the present invention in
detail.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0024] FIG. 1 is a sectional view illustrating the structure of a
general drum type washing machine. As shown in FIG. 1, the drum
type washing machine includes a tub 2 mounted in a machine body 1
such that the tub 2 is supported by a damper 7 and springs 6, a
cylindrical drum 3 mounted in the tub 2 such that the drum 3 can be
rotated about its horizontal axis, and a drive motor axially
coupled to the drum 3.
[0025] The drive motor 5 is located at the rear of the tub 2. The
drive motor 5 includes a stator 5a and a rotor 5b. In order that a
driving force from the rotor 5b is directly transmitted to the drum
without a pulley or a belt, a drum shaft 4, which is rotatable
along with the drum 3, is directly connected to the rotor 5b.
[0026] At a predetermined position in the front of the machine body
1 is mounted a door 8 corresponding to an opening of the drum 3.
Between the door 8 and the drum 3 is mounted a gasket 9 for
maintaining sealability in the drum. Above the door 8 is mounted a
control panel 10 for allowing a user to input a manipulation
command and controlling the overall operation of the washing
machine.
[0027] In the drum type washing machine with the above-stated
construction, a rotating force from the rotor 5b is transmitted to
the drum 3 via the drum shaft 4. During the rotation of the drum 3,
laundry in the drum 3 is lifted by lifters 3a, and then drops due
to gravity, whereby a washing operation is carried out.
[0028] When the laundry, lifted up by the rotation of the drum 3,
reaches a predetermined height, the laundry drops due to gravity,
with the result that the laundry collides with wash water in the
drum 3. This process is repeatedly carried out, and therefore, the
laundry is washed by the friction between the laundry and the wash
water.
[0029] After the above-described washing process is completed, a
spin-drying process is commenced. In the spin-drying process, a
drainage pump (not shown) is driven to drain water through a
drainage line (not shown), and the drum 3 is rotated at a high
speed, whereby the laundry is spin-dried by a centrifugal
force.
[0030] FIG. 2 is a graph illustrating a procedure for entering a
spin-drying step after a wash water draining step during a washing
or rinsing operation of the drum type washing machine.
[0031] After the draining step is completed during the washing or
rinsing operation, the procedure may enter a normal spin-drying
step through a laundry amount-detecting step, an eccentricity
detecting step, and an intermittent spin-drying step.
[0032] The laundry amount-detecting step is a step of detecting the
weight of laundry received in the drum. Generally, the laundry
amount is detected based on time required until the rotation speed
of the drum reaches a predetermined RPM after the rotation of the
drum is initiated. With the increase of the laundry amount, time
required for the rotation speed of the drum to reach the
predetermined RPM increases. Consequently, as shown in FIG. 2, the
laundry amount is detected while the rotation speed of the drum is
increased or decreased within a range of 50 to 100 rpm, such that
the rotation speed of the drum reaches the predetermined rpm.
[0033] Here, it is preferred to perform a laundry untangling
process entailing rotating the drum to uniformly distribute tangled
laundry before the commencement of the laundry amount-detecting
step. This is because, when the rotation of the drum is carried out
in an eccentric fashion due to tangling of the laundry, noise is
generated, and it is difficult to accurately detect the laundry
amount. Preferably, therefore, the drum is rotated once or more in
alternating directions at a rotation speed of approximately 50 rpm,
and then the laundry amount-detecting step is carried out.
[0034] After the completion of the laundry amount-detecting step,
the eccentricity-detecting step is carried out to detect the
eccentricity of the laundry received in the drum and resolve the
eccentricity of the laundry. At the eccentricity-detecting step,
the drum is rotated at a predetermined rotation speed for a
predetermined period of time, such that the laundry is uniformly
distributed before entering the spin-drying step.
[0035] At this time, the drum is rotated at a speed lower than that
during the normal spin-drying process. Preferably, as shown in FIG.
2, the drum is rotated at a rotation speed (rpm.sub.1), which is
predetermined between 100 rpm and 120 rpm, preferably at 108
rpm.
[0036] Also, the intermittent spin-drying step, which is a
preliminary spin-drying step, may be carried out before entering
the normal spin-drying step, in order to reduce noise generated
when a large amount of water is discharged at once in the first
stage of the spin-drying process after the completion of the
eccentricity-detecting step and to reduce load applied to the
motor. FIG. 2 illustrates that the intermittent spin-drying step is
carried out twice. At the first intermittent spin-drying step, the
motor is accelerated to 170 rpm (rpm.sub.1a), and is then
decelerated to 108 rpm (rpm.sub.1). After the motor is decelerated
to 108 rpm (rpm.sub.1), a second eccentricity-detecting step is
carried out. After the completion of the second
eccentricity-detecting step, the second intermittent spin-drying
step is carried out. At the second intermittent spin-drying step,
the motor is accelerated to 400 rpm (rpm.sub.1b), and is then
decelerated to 108 rpm (rpm.sub.1).
[0037] However, when the eccentricity of the laundry is not
resolved at the eccentricity-detecting step, it may be difficult to
enter a subsequent intermittent spin-drying step or normal
spin-drying step. This is because the drum is rotated at a higher
rotation speed at the spin-drying step than at the
eccentricity-detecting step, as described above, and therefore, the
effect caused by the eccentricity of the laundry is serious at the
intermittent spin-drying step or the normal spin-drying step.
[0038] For this reason, the eccentricity-detecting step may be
repeatedly carried out until the eccentricity of the laundry is
resolved. In this case, however, washing time excessively
increases. For a commercial washing machine requiring a user to pay
laundry charges, however, the increased washing time is
economically disadvantageous for the Laundromat.
[0039] Hereinafter, therefore, a detailed description will be given
of a control method for a commercial washing machine that is
capable of preventing the increase of washing time even when the
eccentricity of laundry is not resolved at an
eccentricity-detecting step.
[0040] FIGS. 3A to 3C are graphs illustrating processes carried out
after the completion of a draining step during a washing or rinsing
operation of a commercial washing machine according to the present
invention, and FIG. 4 is a flow chart illustrating a control method
for a commercial washing machine according to the present
invention.
[0041] First, as shown in FIG. 4, when a user inputs a command for
process commencement, a water supplying step, a washing or rinsing
step, and a draining step are sequentially carried out according to
a corresponding washing course (S1 to S3).
[0042] After the completion of the draining step (S3), a laundry
amount-detecting step is carried out to detect the amount of
laundry (S4).
[0043] After the completion of the laundry amount-detecting step
(S4), an eccentricity-detecting step (S6) is carried out to
determine whether the drum is rotated in an eccentric fashion
during the rotation of the drum for a predetermined period of time.
During the drainage of wash water, the laundry is eccentrically
disposed in the drum. Consequently, there is a great possibility
that the drum will be rotated in an eccentric fashion. Especially,
when the drum is rotated in an eccentric fashion at a spin-drying
step at which the drum is rotated at a high speed, the previously
mentioned problem may occur. For this reason, the
eccentricity-detecting step (S5) is carried out to detect whether
the drum is rotated in an eccentric fashion.
[0044] At the eccentricity-detecting step (S5), the drum is rotated
at a predetermined rotation speed for a predetermined period of
time, to move the laundry in the drum. While the laundry is moved
in the drum by the rotation of the drum, it is determined whether
the eccentric rotation of the drum has been resolved. According to
this embodiment, therefore, as shown in FIGS. 3 and 4, the drum is
rotated at an eccentricity detecting RPM (rpm.sub.1), such that the
laundry is redistributed, and then it is determined whether the
eccentricity has been resolved (S5).
[0045] The determination as to whether the eccentricity has been
resolved is made by detecting the eccentricity amount during the
rotation of the drum and determining whether the detected
eccentricity amount is more or less than a predetermined reference
eccentricity amount. That is, it is determined that the
eccentricity has been resolved when the detected eccentricity
amount is less than the predetermined reference eccentricity
amount. On the other hand, it is determined that the eccentricity
has not been resolved yet when the detected eccentricity amount is
more than the predetermined reference eccentricity amount.
[0046] At this time, it is preferred for the eccentricity detecting
RPM (rpm.sub.1) to be less than the rotation speed at the general
spin-drying step. In this embodiment, the eccentricity detecting
RPM (rpm.sub.1) is set to be approximately predetermined between
100 rpm and 120 rpm, preferably at 108 rpm. However, the
eccentricity detecting RPM (rpm.sub.1) is not necessarily limited
to the above-defined value.
[0047] FIG. 5 is a flow chart illustrating a process for
determining whether the eccentricity has been resolved several
times at the eccentricity-detecting step.
[0048] The eccentricity-detecting step may be carried out once.
However, it is preferred for the eccentricity-detecting step to be
repeatedly carried out a predetermined number of times, for example
n times as shown in FIG. 5.
[0049] Specifically, when it is determined that the eccentricity
has not been resolved after the drum is rotated at the eccentricity
detecting RPM (rpm.sub.1) for a predetermined period of time (t),
the eccentricity-detecting step may be repeatedly carried out n
times or less. Of course, when it is determined that the
eccentricity has been resolved before the eccentricity-detecting
step is repeatedly carried out the predetermined number of times
(n), the eccentricity-detecting step (S5) is terminated, and then a
subsequent spin-drying step is commenced. Also, after the
eccentricity-detecting step (S5) is repeatedly carried out the
predetermined number of times (n), the eccentricity-detecting step
(S5) is terminated, and then the spin-drying step is commenced,
even if the eccentricity has not been resolved. In the latter case,
however, the predetermined number of times (n) is preferably
limited to 5 times or less.
[0050] According to the present invention, as described above, the
number of times the eccentricity-detecting step is carried out is
limited to once or the predetermined number of times (n), even
though the eccentricity has not been resolved, whereby it is
possible to reduce inefficient washing time. Also, when further
reduction of the washing time is required, the intermittent
spin-drying step, which will be generally carried out before the
normal spin-drying step, may be omitted to reduce the washing
time.
[0051] According to the present invention, therefore, it is
possible to provide a control method for a commercial washing
machine that is capable of efficiently using washing time. Also, it
is possible to prevent a user from paying extra charges when the
washing time is exceeded. Furthermore, it is possible to reduce
washing cycle duration, thereby enhancing Laundromat profits.
[0052] After the completion of the eccentricity-detecting step
(S5), a spin-drying step is commenced. At this time, the
spin-drying step may be carried out with the drum being rotated at
different rotation speeds, depending upon the determination as to
whether the eccentricity has been resolved at the
eccentricity-detecting step (S5). As previously described, the
faster the rotation speed of the drum is, the greater the effect
due to the eccentricity is. Consequently, when the eccentricity has
been resolved, the spin-drying step is carried out with the drum
being rotated at a normal spin-drying RPM. On the other hand, when
the eccentricity has not been resolved, the spin drying step is
carried out with the drum being rotated at a rotation speed less
than the normal spin-drying RPM.
[0053] According to the present invention, as shown in FIG. 4, a
formal spin-drying step (S6) or an informal spin-drying step (S7)
is selectively carried out depending upon the determination as to
whether the eccentricity has been resolved at the
eccentricity-detecting step (S5). Specifically, when the
eccentricity amount detected at the eccentricity-detecting step
(S5) is less than the reference eccentricity amount, the formal
spin-drying step (S6) is carried out. On the other hand, when the
eccentricity amount detected at the eccentricity-detecting step
(S5) is more than the reference eccentricity amount, the informal
spin-drying step (S7) is carried out. At the informal spin-drying
step (S7), the drum is rotated at an informal spin-drying RPM
(rpm.sub.2) for a predetermined period of time (t). At this time,
the predetermined period of time (t) is between 10 seconds and 30
seconds, preferably 20 seconds. However, the predetermined period
of time (t) is not necessarily limited to the above-defined
value.
[0054] Specifically, FIG. 3A illustrates a control method
characterized in that the eccentricity-detecting step (S5) is
carried out once. The spin-drying pattern is selected in an
alternative way depending upon one determination as to whether the
eccentricity has been resolved. Referring to FIG. 3B, the
eccentricity detection is attempted within the limited
predetermined number of times (n) until the eccentricity amount
detected at the eccentricity-detecting step (S5) is less than the
reference eccentricity amount, and, when it is determined that the
eccentricity has not been resolved, the informal spin-drying step
(S7) is carried out with the drum being rotated at the informal
spin-drying RPM (rpm.sub.2) for the predetermined period of time
(t).
[0055] Here, as shown in FIG. 3A, the informal spin-drying RPM
(rpm.sub.2) may be controlled to be the same as the eccentricity
detecting RPM (rpm.sub.1) at the eccentricity-detecting step (S5).
Alternatively, as shown in FIG. 3B, the informal spin-drying RPM
(rpm.sub.2) is preferably more than the eccentricity detecting RPM
(rpm.sub.1) and less than a formal spin-drying RPM (rpm.sub.3),
which will be described below, at the formal spin-drying step
(S6).
[0056] When the informal spin-drying RPM (rpm.sub.2) and the
eccentricity detecting RPM (rpm.sub.1) are the same, as shown in
FIG. 3A, the informal spin-drying step (S7) is carried out with the
drum being rotated at the same RPM as the eccentricity detecting
RPM (rpm.sub.1) for the predetermined period of time (t), without
additional acceleration of the drum after the completion of the
eccentricity-detecting step (S5), whereby a reduction in washing
time and satisfactory spin-drying effects are achieved.
[0057] On the other hand, when the informal spin-drying RPM
(rpm.sub.2) is preferably more than the eccentricity detecting RPM
(rpm.sub.1) and less than the formal spin-drying RPM (rpm.sub.3) at
the formal spin-drying step (S6), as shown in FIG. 3B, the informal
spin-drying step (S7) is carried out with the drum being rotated at
appropriate RPM for the predetermined period of time (t), without
excessive acceleration of the drum in a state in which the
eccentricity is not resolved, whereby a reduction in washing time
and satisfactory spin-drying effects are achieved.
[0058] According to the present invention, meanwhile, when the
eccentricity detection is attempted within the limited
predetermined number of times (n) until the eccentricity amount
detected at the eccentricity-detecting step (S5) is less than the
reference eccentricity amount, and, as a result, the eccentricity
has been resolved, as shown in FIG. 3C, the formal spin-drying step
(S6) is carried out with the drum being rotated at the formal
spin-drying RPM (rpm.sub.3) after the completion of the
eccentricity-detecting step (S5). At this time, the formal
spin-drying RPM (rpm.sub.3) at the formal spin-drying step (S6) is
more than the eccentricity detecting RPM (rpm.sub.1) at the
eccentricity-detecting step (S5).
[0059] At the formal spin-drying step (S6), therefore, the
eccentricity detection is attempted within the limited
predetermined number of times (n) with the eccentricity-detecting
step and the intermittent spin-drying step, which are repeatedly
carried out several times, being omitted, and then the spin-drying
process is carried out. Consequently, the washing time is reduced.
Furthermore, the spin-drying process is carried out at RPM more
than that at the informal spin-drying step (S7) in a state in which
the eccentricity has been resolved, whereby spin-drying efficiency
is further improved.
[0060] After the completion of the spin-drying step (S6, S7), the
procedure enters a water supplying step, and the remaining washing
operation is carried out to complete the washing of the laundry
(S8).
[0061] As apparent from the above description, the present
invention has the effect of providing a short washing cycle
satisfying the purpose of a commercial washing machine, thereby
improving the economic efficiency of the commercial washing
machine.
[0062] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the inventions. Thus,
it is intended that the present invention covers the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *