Abstract:
Disclosed herein are a door lock control device and method of a washing machine which sense opening or closing of a door using a door lock switch. Since the door is locked or unlocked and the closing or opening of the door is sensed using one door lock switch without adding a separate switch to sense the closing or opening of the door, cost may be decreased.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2009-0097215, filed on Oct. 13, 2009 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments relate to a door lock control apparatus and method of a washing machine which senses opening and closing of a door using a door lock switch. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, a washing machine (generally, a drum type washing machine) includes a tub to contain water (washing water or rinsing water), a drum rotatably mounted in the tub to contain laundry, and a motor to generate driving force to rotate the drum, and washes the laundry by raising and dropping the laundry in the drum along the inner wall of the drum when the cylindrical drum is rotated. 
         [0006]    In such a washing machine, a door is openably and closably provided such that the laundry is put into or taken out of the drum, and a door lock switch to lock the door such that the door is not opened during the operation of the washing machine is provided on one side of the door. 
         [0007]    The door lock switch simultaneously performs a lock/unlock function of the door and a power on/off function of an electrical part. To this end, the electrical part is operated only when the door is closed, such that a user is protected from accidents during mechanical operation, such as the rotation of the drum. 
         [0008]    In the door lock switch, a bimetal latch or a solenoid is used to perform the lock/unlock operation of the door. As the quality of a product is improved, a time consumed for lock/unlock is relatively increased. Thus, the solenoid scheme is preferred to the bimetal latch scheme. In order to reduce costs, even in the solenoid scheme, a method of controlling a lock/unlock operation by toggling one solenoid instead of two solenoids has been developed. 
         [0009]    Recently, a door lock switch including a switch to sense opening or closing of a door in addition to a basic operation such as a lock/unlock operation of the door has been developed. When the door is not closed, the electrical part is not powered on so as to prevent Product Liability (PL) accidents in advance. However, since a separate switch is added to mechanically reject the opening or closing of the door, this door lock switch is not preferable in terms of cost reduction. 
       SUMMARY 
       [0010]    Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
         [0011]    Therefore, it is an aspect to provide a door lock control apparatus and method of a washing machine, which performs a lock/unlock operation of a door and senses the closing or opening of the door using a door lock switch without adding a separate switch to sense the closing or opening of the door. 
         [0012]    Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
         [0013]    In accordance with one aspect, there is provided door lock control device of a washing machine, the door lock control device including: a door; a door lock switch turned on/off according to closing or opening of the door to mechanically lock or unlock the door and to sense the closing or opening of the door; a sensor to sense an operation state of the door lock switch and to output a door closing/opening signal; and a control unit to determine the closed or opened state of the door according to the door closing/opening signal and to control an operation of the washing machine. 
         [0014]    The door lock switch may include a door switch turned on/off according to the closing or opening of the door and a main switch to power on or off an electrical part, and the door switch and the main switch may be configured by one switch. 
         [0015]    The control unit may stop the operation of the washing machine if a determination is that the door is opened during the operation of the washing machine. 
         [0016]    The door lock control device may further include a main motor driven to perform the operation of the washing machine, and the control unit may stop the driving of the main motor if a determination is made that the door is opened during the operation of the washing machine. 
         [0017]    The control unit may output a door lock control signal if a determination is made that the door is closed, and a door lock relay to turn on a main switch according to the door lock control signal may be further included. 
         [0018]    In accordance with another aspect, there is provided a door lock control device of a washing machine, the door lock control device including: a door; a door lock switch turned on/off according to opening or closing of the door to mechanically lock or unlock the door and to sense the closing or opening of the door; and a sensor to optically sense an operation state of the door lock switch (or door) and to output a door opening/closing signal, wherein the door lock switch senses whether the door is forcibly opened in a state in which the door is locked. 
         [0019]    The door lock control device may further include a control unit to determine the opened or closed state of the door according to the door opening/closing signal and to output a door lock control signal if a determination is the door is closed, and a door lock relay to operate the door lock switch according to the door lock control signal. 
         [0020]    The door lock switch may include a door switch, of a contact type which is turned on or off according to the closing or opening of the door to sense the closing or opening of the door, a main solenoid in which current flows according to an operation of the door lock relay, and a main switch switched by the main solenoid to power on or off an electrical part. 
         [0021]    The door lock control signal may operate the door lock relay in a pulsed mode to enable current to flow in the main solenoid for a predetermined time. 
         [0022]    The door switch may be connected between the main solenoid and a power supply, the main solenoid may be connected between the door lock relay and the door switch, and the main switch may connect the power supply and the electrical part. 
         [0023]    The door lock switch may have three terminals to connect the door switch, the main solenoid and the main switch. 
         [0024]    The door lock control device may further include a control unit to control an operation of the washing machine according to the door opening/closing signal, and a main motor driven under the control of the control unit, and the control unit may stop the driving of the main motor if a determination is made that the door is opened during the operation of the washing machine. 
         [0025]    The door lock control device may further include a display unit to display an error message according to the stoppage of the main motor under the control of the control unit. 
         [0026]    In accordance with another aspect, there is provided a door lock control method of a washing machine, the door lock control method including: operating a door lock switch to lock the door if a door is closed; performing an operation of the washing machine in a state in which the door is locked; sensing whether the door is opened during the operation of the washing machine; and stopping the operation of the washing machine if the door is sensed to be opened during the operation of the washing machine. 
         [0027]    The door lock control method may further include sensing an operation state of the door lock switch and outputting a door opening/closing signal, and determining the opened or closed state of the door according to the door opening/closing signal and controlling the operation of the washing machine. 
         [0028]    According to the door lock control device and method of the washing machine, since the door is locked or unlocked and the opening or closing of the door is sensed using one door lock switch without adding a separate switch to sense the opening or closing of the door, cost may be decreased. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0030]      FIG. 1  is a perspective view showing the configuration of a washing machine according to an embodiment; 
           [0031]      FIG. 2  is a diagram showing a door lock control circuit of a washing machine according to an embodiment; 
           [0032]      FIG. 3  is a pulse waveform diagram of a door lock control signal according to an embodiment; 
           [0033]      FIG. 4  is a flowchart illustrating a door lock control method of a washing machine according to an embodiment; 
           [0034]      FIG. 5  is a diagram showing a closed loop which is formed in order to sense the opening or closing of a door of a washing machine according to an embodiment; and 
           [0035]      FIG. 6  is a diagram showing a closed loop which is formed in order to control a lock operation of a door of a washing machine according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures. 
         [0037]    Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
         [0038]      FIG. 1  is a perspective view showing the configuration of a washing machine according to an embodiment of the present invention. 
         [0039]    In  FIG. 1 , the washing machine according to the embodiment includes a main body  10  substantially having a box shape and including an opening  11  formed in a front surface thereof to put or take laundry into or out of the washing machine, a cylindrical drum  12  rotatably mounted in the main body  12  to contain the laundry, and a door  20  provided in the front surface of the main body  10  to open or close the opening  11 . 
         [0040]    The door  20  is rotatably coupled to the main body  10  by a hinge member  21  provided on one side of the washing machine and is coupled to a door lock device  30  by a hook member  22  provided on the other side of the washing machine, and the door  20  is locked such that the door  20  is not opened during an operation of the washing machine. 
         [0041]    A coupling member  31  to couple or decouple the hook member  22  to or from the main body  10  is formed in the door lock device  30  so as to lock or unlock the door  20 . 
         [0042]    In addition, a control panel  40  to control the washing machine is provided on an upper side of the front surface of the main body  10 , and a detergent drawer  41  is provided on one side of the control panel  40 . 
         [0043]    Although not shown, a main motor is provided on an outer side of a rear surface of the drum  12  as a driving device to rotate the drum  12 . 
         [0044]      FIG. 2  is a diagram showing a door lock control circuit of a washing machine according to an embodiment, and  FIG. 3  is a pulse waveform diagram of a door lock control signal according to an embodiment. 
         [0045]    In  FIG. 2 , a door lock control device of a washing machine of one embodiment includes a door lock switch  110  to lock/unlock the door  20  and to sense the closing or opening of the door  20 , a sensor  120  to sense the closing or opening state of the door  20  according to an operation of the door lock switch  110  to output a door opening/closing signal, a control unit  130  to receive the door opening/closing signal from the sensor  120 , to the lock/unlock of the door  20  and to control the operation of the washing machine, a 3-pole door lock relay  140  to operate the door lock switch  110  to power on or off an electrical part according to the door lock control signal of the control unit  130 , a main motor  150  driven according to a motor control signal of the control unit  130 , and a display unit  160  to display an operation state of the washing machine according to a display control signal of the control unit  130 . 
         [0046]    The door lock switch  110  includes a door (single) switch  111 , of a contact type which is turned on/off according to the closing or opening of the door  20  to sense the closing or opening of the door  20 , a main or solenoid operated switch  112  to power on/off the electrical part (a heater, a valve or the like), and a main solenoid  113  in which current flows according to an operation of the door lock relay  140  control a switching operation of the main switch  112 . 
         [0047]    The sensor part  120  includes a photo-coupler  121  to sense optically a contact state of the door switch  111  according to the on/off state of the door switch  111  and to output the door opening/closing signal to an input terminal (Sensing) of the control unit  130 , a current limit resistor  122  to limit current of a power supply  100  applied to the photo-coupler  121 , and an integrator  123  to stabilize the current value of the door opening/closing signal input to the input terminal (Sensing) of the control unit  130 . The integrator  123  includes a resistor R 1  and a capacitor C 1 . 
         [0048]    The control unit  130  determines the opening or closing state of the door  20  according to the door opening/closing signal received from the sensor part  120  and controls the driving of the door lock relay  140  and the driving of the main motor  150 . For example, if the control unit  130  determines that the door  20  is closed, the control unit outputs a door lock control signal to the door lock relay  140  through an output terminal (Door_Lock). The door lock control signal output through the output terminal (Door_Lock) is shown in  FIG. 3 . 
         [0049]    In  FIG. 3 , in the door lock control signal, a rectangular pulse for a predetermined time ( 25  to 30 msec) is output such that the door lock relay  140  operates in a pulsed mode, and a time interval between pulses is gradually increased (1 sec, 3 min, 30 min, . . . ) according to the number of times of sensing of the contact of the door switch  111  to protect the door lock relay  140 . 
         [0050]    The door lock relay  140  includes a 3-pole switch  141  to switch terminals COM, NC and NO to control the switching operation of the main switch  112  according to the door lock control signal output from the output terminal (Door_Lock) of the control unit  130  and a control solenoid  142  in which current flows according to the door lock control signal to switch the terminals of the 3-pole switch  141 . 
         [0051]    Accordingly, when the door lock relay  140  receives the door lock control signal shown in  FIG. 3  from the control unit  130 , current flows in the control solenoid  142  for the predetermined time (25 to 30 msec) such that the common terminal COM of the 3-pole switch  141  is switched from the normally closed terminal NC to the normally open terminal NO. When the common terminal COM of the 3-pole switch  141  is switched from the normally closed terminal NC to the normally open terminal NO, current flows in the main solenoid  113  of the door lock switch  110  to turn on the main switch  112  such that the door  20  is mechanically locked. 
         [0052]    Thereafter, when the predetermined time (25 to 30 msec) elapses, the rectangular pulse input to the control solenoid  142  of the door lock relay  140  becomes a low level, the current flowing in the control solenoid  142  is cut off, and the common terminal COM of the 3-pole switch  141  is switched from the normally open terminal NO to the normally closed terminal NC again. At this time, the main switch  112  of the door lock switch  110  is held at the on state and thus the door  20  is successfully locked. 
         [0053]    The main motor  150  performs or stops the operation of the washing machine including a washing cycle, a rinsing cycle and a dehydrating cycle according to the motor control signal of the control unit  130 . For example, when the control unit  130  determines that the door  20  is opened, the driving of the main motor  150  is stopped such that the operation of the washing machine is stopped. 
         [0054]    The display unit  160  displays the operation state of the washing machine to a user according to the display control signal from the control unit  130  and displays an error message if the user operates the washing machine in a state in which the door  20  is opened or if the door  20  is forcibly opened during the operation of the washing machine. 
         [0055]    Hereinafter, the operation of the door lock control device of the washing machine and the effect thereof will be described. 
         [0056]    Prior to the description of the operation, the common terminal COM is connected to the normally closed terminal NC in the 3-pole switch  141  of the door lock relay  140 . 
         [0057]      FIG. 4  is a flowchart illustrating a door lock control method of a washing machine according to an embodiment. 
         [0058]    In  FIGS. 4 and 5 , when the door  20  of the washing machine is closed, the contact of the door switch  111  of the door lock switch  110  is closed. If the contact of the door switch  111  is closed, the current of the power supply  100  flows to the 3-pole switch  141  of the door lock relay  140  through the photo-coupler  121  of the sensor unit  120 . At this time, in the 3-pole switch  141  of the door lock relay  140 , since the common terminal COM is connected to the normally closed terminal NC, the current passes through the 3-pole switch  141  so as to form a closed loop from the door switch  111  of the door lock switch  110  to the power supply (see a thick line of  FIG. 5 ). 
         [0059]    Since minute current flows in the photo-coupler  121  through the contact of the door switch  111 , the photo-coupler  121  senses the contact state of the door switch  111  and outputs the door opening/closing signal to the input terminal (Sensing) of the control unit  130 . 
         [0060]    Accordingly, the control unit  130  determines the opened/closed state of the door  20  according to the door opening/closing signal received from the sensor unit  120  and determines whether the door switch  111  is turned on ( 200 ). 
         [0061]    As the result of the determination of Operation  200 , when the door switch  111  is turned on, the control unit  130  determines that the door  20  is closed and outputs the door lock control signal to the door lock relay  140  through the output (Door_Lock) ( 202 ). 
         [0062]    In the door lock control signal, as shown in  FIG. 3 , the rectangular pulse is output for a predetermined time (about 25-30 msec) such that the door lock relay  140  operates in the pulsed mode, and the time interval between pulses is gradually increased (1 sec, 3 min, 30 min, . . . ) according to the number of times of sensing of the contact of the door switch  111  to protect the door lock relay  140 . 
         [0063]    Accordingly, in the door lock relay  140 , the current flows in the control solenoid  142  for the predetermined time (25 to 30 msec) according to the door lock control signal output from the output terminal (Door_Lock) of the control unit  130  and the common terminal COM of the 3-pole switch  141  is switched from the normally closed terminal NC to the normally open terminal NO ( 204 ). 
         [0064]    When the common terminal COM of the 3-pole switch  141  is switched from the normally closed terminal NC to the normally open terminal NO, current of the power supply  100  flows to the main solenoid  113  of the door lock switch  110  through the common terminal COM and the normally open terminal NO of the 3-pole switch  141  of the door lock relay  140 . At this time, the current passing through the main solenoid  113  forms a closed loop from the door switch  111  to the power supply (see a thick line of  FIG. 6 ). 
         [0065]    Accordingly, the current flows in the main solenoid  113  of the door lock switch  110 , the main switch  112  is turned on, and the door  20  is mechanically locked ( 206 ). 
         [0066]    When the main switch  112  is turned on and the door is successfully locked, the operation of the washing machine including the washing cycle, the rinsing cycle and the dehydrating cycle is performed according to a washing condition selected by the user ( 208 ). 
         [0067]    If the door  20  is forcibly opened during operation of the washing machine for some reason, only the door  20  is opened in a state in which the main switch  112  is turned on. When the door  20  is opened, the contact of the door switch  111  of the door lock switch  110  is opened. If the contact of the door switch  111  is opened, the current of the power supply  100  does not flow to the 3-pole switch  141  of the door lock relay  140  through the photo-coupler  121  of the sensor unit  120 . At this time, since the common terminal COM and the normally closed terminal NC are connected again in the 3-pole switch  141  of the door lock relay  140 , minute current does not flow in the photo-coupler  121 . Thus, the photo-coupler  121  senses the contact state of the door switch  111  and outputs the door opening/closing signal to the input terminal (Sensing) of the control unit  130 . 
         [0068]    Accordingly, the control unit  130  determines the opened or closed state of the door  20  according to the door opening/closing signal received from the sensor unit  120  and determines whether the door switch  111  is turned off ( 210 ). 
         [0069]    As the result of determination of Operation  210 , when the door switch  111  is turned off, the control unit  130  determines that the door  20  is opened and outputs the motor control signal to the main motor  150  ( 212 ). 
         [0070]    Then, the main motor  150  is stopped according to the motor control signal of the control unit  130  so as to stop the operation of the washing machine ( 214 ). 
         [0071]    In addition, the control unit  130  outputs the motor control signal and outputs the display control signal to the display unit  160  ( 216 ). 
         [0072]    Accordingly, the display unit  160  displays an error signal according to the display control signal of the control unit  130  ( 218 ). 
         [0073]    Although the door lock control device is applied to a washing machine in the embodiments, the embodiments are not limited thereto. Even when the embodiments are applied to a dish washer, a drier, a cooker or the like, the same advantages may be obtained as in the embodiments. 
         [0074]    Although a few embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.