Patent Publication Number: US-11639575-B2

Title: Washing machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0086450, filed on Jul. 17, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     The disclosure relates to a washing machine, and more particularly, to a detergent supply device having an improved locking structure and a washing machine including the same. 
     2. Description of the Related Art 
     Generally, a washing machine is a device for washing laundry by rotating a cylindrical rotary tub containing the laundry and washing water. As a type of washing machine, there are a drum washing machine in which laundry is washed by falling down after being lifted upward along an inner circumferential surface of a rotary tub as the rotary tub, which is disposed substantially horizontally, rotates in the forward and reverse directions with respect to a horizontal axis, and a vertical axis washing machine in which laundry is washed using a water current generated by a pulsator disposed inside a rotary tub as the rotary tub, which is disposed substantially vertically, rotates in the forward and reverse directions with respect to a vertical axis. 
     A drum washing machine includes a cabinet forming an outer appearance, a drum rotated inside the cabinet by a rotational force of a motor, a tub disposed between the drum and the cabinet to accommodate washing water, a front panel mounted on a front side of the cabinet and having a center opening to allow laundry to be put therein and taken out therefrom, and a door installed on the front panel to open and close the opening and preventing the laundry from escaping. 
     A detergent supply device for supplying washing water mixed with a detergent to the tub is installed at an upper portion of the drum washing machine. 
     The detergent supply device is disposed in an upper front side of the drum washing machine and includes a box-shaped case with an open front, and a drawer-type detergent container mounted on the case to be movable in and out of the case through the open front of the case. 
     A user may open or close the case by pulling or pushing the detergent container. 
     Recently, an automatic detergent supply device, which may automatically supply a detergent or a softener of a required amount by a pump during each washing after the amount of liquid detergent or softener to be able to be supplied dozens of times is stored in advance, is used. 
     In the case of such an automatic detergent supply device, a connection structure between the washing machine case and the detergent container becomes complicated, so that in closing and opening operations, a large difference in a resistance force occurs, and at the same time, mechanically combining and separating may be difficult. 
     In addition, when the detergent container of the detergent supply device and a combining portion of the washing machine body are not firmly combined, the detergent may not be supplied or the detergent may be supplied at an inappropriate timing. 
     SUMMARY 
     In accordance with an aspect of the disclosure, a washing machine includes a main body, a tub disposed inside the main body to accommodate water, a detergent case configured to supply a detergent to the tub, and a locking device configured to detachably connect the detergent case to the main body, wherein the locking device includes a first locking member disposed in the main body, and a second locking member disposed in the detergent case to lock or unlock the first locking member by being pressed. 
     The main body may include a counterpart configured such that the detergent case is installed, and the first locking member may be provided on the counterpart. 
     The first locking member may include a first locking portion formed to be in contact with at least a portion of the second locking member, and the first locking portion may include a first locking surface having an inclination of a first angle. 
     The counterpart may include at least one of a front panel provided in front of the main body and a frame provided inside the main body such that the detergent case is installed. 
     The first locking surface may be formed on at least a portion of the counterpart. 
     The second locking member may include a pressing portion rotatably installed in the detergent case, a second locking portion extending from the pressing portion to correspond to the first locking portion, and a rotation shaft supporting the second locking portion to be rotated by pressing of the pressing portion. 
     The second locking portion may be provided to correspond to the first locking surface and may include a second locking surface having an inclination of a second angle. 
     The second angle may be greater than or equal to the first angle. 
     The washing machine may further include an elastic member elastically supporting the second locking member. 
     The elastic member may be disposed between the detergent case and the second locking member. 
     The detergent case may include a detergent case body configured to accommodate the detergent, a handle provided in front of the detergent case body to be gripped by a user, and a second locking portion installation portion provided between the handle and the detergent case body such that the second locking member is installed. 
     The second locking portion installation portion may include a second locking member installation bracket configured such that the second locking member is rotatably installed. 
     When the second locking portion is locked with the first locking portion, the second locking portion may be exposed to the outside of the second locking portion installation portion. 
     When the second locking portion is unlocked with the first locking portion, the second locking portion may be moved to the inside of the second locking portion installation portion. 
     In accordance with another aspect of the disclosure, a washing machine includes a main body, and a detergent supply device mounted on the main body, wherein the detergent supply device includes a detergent case configured to accommodate a detergent, and a locking device locking or unlocking the detergent case such that a detergent case is detachable connected to the main body, and wherein the locking device includes a first locking member provided in the main body, and a second locking member disposed in the detergent case and configured to lock or unlock the first locking member by pressing of a user. 
     The first locking member may include a first locking portion formed to be in contact with at least a portion of the second locking member, and the first locking portion may include a first locking surface having an inclination of a first angle. 
     The second locking member may include a second locking portion extending from the pressing portion to correspond to the first locking portion, and a rotation shaft supporting the second locking portion to be rotated by pressing of the pressing portion. 
     The second locking portion may be provided to correspond to the first locking surface and may include a second locking surface having an inclination of a second angle. 
     The second angle may be greater than or equal to the first angle. 
     The washing machine may further include an elastic member disposed between the detergent case and the second locking member to elastically support the second locking member. 
     Additional aspects of the disclosure 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 disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG.  1    is a perspective view of a washing machine according to an embodiment of the disclosure; 
         FIG.  2    illustrates a washing machine equipped with a detergent case to which a locking device is applied according to an embodiment of the disclosure; 
         FIG.  3    is a plan view of the detergent case to which the locking device is applied according to an embodiment of the disclosure; 
         FIG.  4    is a partially exploded perspective view of the detergent case installed in a main body according to an embodiment of the disclosure; 
         FIG.  5    is an exploded perspective view of the detergent case according to an embodiment of the disclosure; 
         FIG.  6    is a cross-sectional view taken along line A-A′ in  FIG.  1   , illustrating the locking device of the detergent case according to an embodiment of the disclosure; 
         FIG.  7    is an enlarged view of a portion B in  FIG.  6   , illustrating the locking device according to an embodiment of the disclosure; 
         FIG.  8    illustrates the detergent case when the locking device is in a closing position according to an embodiment of the disclosure; 
         FIG.  9    is an enlarged view of a portion C in  FIG.  8   , illustrating a locking operation of the locking device according to an embodiment of the disclosure; 
         FIG.  10    illustrates the detergent case when the locking device is in an openable position according to an embodiment of the disclosure; 
         FIG.  11    is an enlarged view of a portion D in  FIG.  10   , illustrating an opening operation of the locking device according to an embodiment of the disclosure; 
         FIG.  12    illustrates the detergent case when the locking device is in an unlocking position according to an embodiment of the disclosure; and 
         FIG.  13    is an enlarged view of a portion E in  FIG.  12   , illustrating an unlocking operation of the locking device according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Configurations shown in the embodiments and the drawings described in the present specification are only the preferred embodiments of the present disclosure, and thus it is to be understood that various modified examples, which may replace the embodiments and the drawings described in the present specification, are possible when filing the present application. 
     Like reference numbers or signs in the various drawings of the application represent parts or components that perform substantially the same functions. 
     The terms used herein are for the purpose of describing the embodiments and are not intended to restrict and/or to limit the disclosure. For example, the singular expressions herein may include plural expressions, unless the context clearly dictates otherwise. Also, the terms “comprises” and “has” are intended to indicate that there are features, numbers, steps, operations, elements, parts, or combinations thereof described in the specification, and do not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts, or combinations thereof. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another. For example, without departing from the scope of the disclosure, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term “and/or” includes any combination of a plurality of related items or any one of a plurality of related items. 
     It is an aspect of the disclosure to provide a detergent supply device with an improved locking structure and a washing machine including the same. 
     It is another aspect of the disclosure to provide a detergent supply device with an improved locking structure for easy withdrawal and fastening of a detergent case and a washing machine including the same. 
     It is another aspect of the disclosure to provide a detergent supply device capable of improving usability by providing a constant force for opening and dosing the detergent case and a washing machine including the same. 
     Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective view of a washing machine according to an embodiment of the disclosure,  FIG.  2    illustrates a washing machine equipped with a detergent case to which a locking device is applied according to an embodiment of the disclosure, and  FIG.  3    is a plan view of the detergent case to which the locking device is applied according to an embodiment of the disclosure. 
     As illustrated in  FIGS.  1  to  3   , a washing machine  1  includes a main body  10  forming an outer appearance and configured to accommodate various components therein, a tub (not shown) disposed inside the main body  10  to store mixed water in which washing water and a detergent are mixed, a rotatable drum  30  disposed inside the tub to receive laundry, and a driving device (not shown) for rotating the drum  30 . The driving device (not shown) may rotate the drum  30  forward and backward in the rear of the tub to perform washing, rinsing, and dehydrating operations. 
     The main body  10  may be formed in a substantially hexahedral shape. The main body  10  may be formed in a box shape with an open front side. The main body  10  may include a rear surface  11  and opposite side surfaces  12  and  13  disposed on one side and the other side in the front of the rear surface  11 . The front panel  20  may be provided on the open front side of the main body  10 , and a top cover  14  and a base  15  may be provided on upper and lower sides, respectively. The top cover  14  and the base  15  may be formed of rectangular plates having sizes corresponding to the upper and lower sides of the main body  10 , respectively. 
     The front panel  20  may include a first front panel  21  and a second front panel  22  disposed above the first front panel  21 . 
     The first front panel  21  may be disposed on the front side of the main body  10 . A lower end of the first front panel  21  may be coupled to the base  15 . An opening  23  may be formed on the first front panel  21  to allow laundry to be put into and taken out of the drum  30 . The opening  23  of the first front panel  21  is formed to allow laundry to be put or taken through the front side of the main body  10 . The opening  23  of the first front panel  21  may be opened and closed by a door  40 . The door  40  may include a door frame  41  and a door glass  43 . The door glass  43  may be formed of a transparent tempered glass material so that the inside of the main body  10  may be viewed. 
     The second front panel  22  may be provided on an upper front side of the main body  10 . The second front panel  22  may be disposed above the first front panel  21 . An upper end of the second front panel  22  may be coupled to the top cover  14 . 
     The second front panel  22  may be provided with a control panel  50  including an input  51  for receiving an operation command from a user and a display  52  for displaying operation information of the washing machine  1 . 
     A detergent supply device  100  for supplying a detergent into the tub may be installed in the second front panel  22 . The second front panel  22  may include a detergent supply device installation portion  60  formed by cutting at least a portion thereof. The disclosure illustrates that the detergent supply device installation portion  60  is formed on the left side of the second front panel  22 , but is not limited thereto. For example, the detergent supply device installation portion  60  may be formed on the right side of the second front panel  22  or may also be formed on the first front panel  21 . 
     Water supply valves (not shown) and water supply pipes (not shown) connected to an external water supply source (not shown) to supply washing water to the inside of the tub and to control water supply may be installed above the tub. The water supply pipes may be connected to the detergent supply device  100 . 
     The detergent supply device  100  may be connected to the tub through a supply pipe (not shown). Washing water is mixed with the detergent through the detergent supply device  100 , and the mixed water in which the washing water and the detergent are mixed may be supplied into the tub. 
     A drain pump (not shown) and a drain pipe (not shown) for forcibly draining washing water inside the tub to the outside of the main body  10  after washing is finished may be provided below the tub. 
     The detergent supply device  100  may be installed in the second front panel  22 . The detergent supply device  100  may be installed on the detergent supply device installation portion  60 . A detergent case cover installation surface  61  may be formed on the detergent supply device installation portion  60  so that a detergent case cover  140  of the detergent supply device  100 , which will be described later, may be coupled thereto. It is appropriate that the detergent case cover installation surface  61  is formed by being recessed toward an inner side of the second front panel  22 . 
     The detergent supply device  100  may supply a detergent in an automatic detergent supply method or a manual detergent supply method according to the selection of the user, and in the automatic detergent supply method, the detergent may be additionally supplied as the user needs. 
     The input  51  of the control panel  50  may be provided with a dial or a button for supplying the detergent so that the user may select the supply of the detergent. 
     The detergent supply device  100  may include a housing  110  installed inside the main body  10 , a detergent case  120  accommodating a detergent and a softener and movably coupled to the inside of the housing  110 , and a locking device  200  configured to lock or unlock the detergent case  120  so that the detergent case  120  may be separated from the main body  10 . 
     The detergent supply device  100  may further include a water supply unit  115  coupled to the housing  110  or the detergent case  120  to supply water. 
     The housing  110  may include a housing body  111  accommodating the detergent case  120  therein, and a housing opening  113  formed on a front side of the housing body  111  to allow the detergent case  120  to be withdrawn outside or put inside. The housing  110  is configured to guide the detergent case  120  to be withdrawn outside or put inside. The housing  110  may be disposed at an inner upper portion of the main body  10 . The disclosure illustrates that the housing  110  is disposed at the left side of the inner upper portion of the main body  10 , but is not limited thereto. For example, the housing  110  may be disposed at a lower portion of the main body  10 . 
     The detergent case  120  may be installed to be movable inside and outside the housing  110  through the housing opening  113  of the housing  110 . The detergent case  120  may include a detergent case body  121  and the detergent case cover  140  provided in front of the detergent case body  121 . The detergent case cover  140  may include a handle  141  provided to be gripped by the user. The handle  141  may be formed by recessing at least a portion of the detergent case cover  140 . The handle  141  may be provided in front of the detergent case body  121 . The detergent case cover  140  may be formed to correspond to the detergent supply device installation portion  60  of the front panel  20 . At least a portion of a rear surface of the detergent case cover  140  may be formed to correspond to the detergent case cover installation surface  61  of the detergent supply device installation portion  60 . 
     The detergent case body  121  is formed in a box shape with an open upper side. The inside of the detergent case body  121  may be partitioned by a plurality of partition walls  122 . A plurality of detergent accommodating portions  123  is formed in the inside of the detergent case body  121  partitioned by the plurality of partition walls  122 , and a detergent container (not shown) and a softener container (not shown) for accommodating a detergent and a softener may be mounted in the plurality of detergent accommodating portions  123 . 
     The detergent case cover  140  is installed to cover a front side of the detergent case body  121 . The detergent case cover  140  and the detergent case body  121  may be combined in a hook manner. 
     A detergent case bracket  130  may be provided between the detergent case cover  140  and the detergent case body  121 . The detergent case cover  140  may be coupled to a front surface of the detergent case bracket  130 . The detergent case bracket  130  may be coupled to a front surface of the detergent case body  121 . 
     The locking device  200 , which will be described later, may be installed on the detergent case bracket  130 . The disclosure illustrates that the detergent case bracket  130  is separately provided and combined in front of the detergent case body  121 , but is not limited thereto. For example, the detergent case bracket  130  may be integrally formed with the detergent case body  121 . 
     The locking device  200  for detachably connecting the detergent case  120  to the main body  10  may include a first locking member  210 , and a second locking member  220  provided to lock or unlock the first locking member  210 . 
     The first locking member  210  may be disposed in the main body  10 . The first locking member  210  may be provided on the second front panel  22  of the main body  10 . The first locking member  210  may be provided in the detergent supply device installation portion  60  of the second front panel  22 . The first locking member  210  may be provided on a counterpart where the detergent case  120  is installed. The counterpart where the detergent case  120  is installed may be provided in the main body  10 . The counterpart may include a separate frame (not shown) provided inside the main body  10  such that the front panel  20  provided on the front side of the main body  10  and the detergent case  120  are installed. 
     The second locking member  220  may be disposed in the detergent case  120 . The second locking member  220  may be configured to lock or unlock the first locking member  210  by rotating as the user presses the second locking member  220 . 
     At least a portion of the second locking member  220  may be exposed to the outside of the detergent case  120 . The detergent case  120  may be provided with a second locking portion installation opening  125  to expose the at least a portion of the second locking member  220 . The second locking portion installation opening  125  may be formed by opening a portion of an upper surface of the detergent case  120 . The second locking member  220  may be exposed or non-exposed by rotating through the second locking portion installation opening  125  formed on the upper surface of the detergent case  120 . 
       FIG.  4    is a partially exploded perspective view of the detergent case installed in a main body according to an embodiment of the disclosure,  FIG.  5    is an exploded perspective view of the detergent case according to an embodiment of the disclosure,  FIG.  6    is a cross-sectional view taken along line A-A′ in  FIG.  1   , illustrating the locking device of the detergent case according to an embodiment of the disclosure, and  FIG.  7    is an enlarged view of a portion B in  FIG.  6   , illustrating the locking device according to an embodiment of the disclosure. 
     As illustrated in  FIGS.  4  and  7   , the detergent case  120  of the detergent supply device  100  may include the detergent case body  121  and the detergent case cover  140  provided in front of the detergent case body  121 . 
     The detergent case body  121  is formed in a box shape with the open upper side. The detergent case cover  140  is installed to cover the front side of the detergent case body  121 . The detergent case cover  140  and the detergent case body  121  may be combined in a hook manner. 
     A detergent case body bracket  124  may be provided on the front surface of the detergent case body  121 . The detergent case body bracket  124  is provided such that the detergent case bracket  130  may be coupled thereto. The detergent case body bracket  124  may be formed to correspond to the size and shape of the detergent case body  121 . The second locking portion installation opening  125  for installing the second locking member  220  may be formed on an upper surface  124   a  of the detergent case body bracket  124 . The second locking portion installation opening  125  may be formed by cutting at least a portion of the upper surface  124   a  of the detergent case body bracket  124 . The second locking portion installation opening  125  may be formed by cutting in a moving direction of the detergent case  120  on the upper surface  124   a  of the detergent case body bracket  124 . 
     The detergent case bracket  130  may be coupled from front of the detergent case body bracket  124 . The detergent case bracket  130  may be provided with a second locking portion installation hole  134  corresponding to the second locking portion installation opening  125  of the detergent case body bracket  124 . The second locking portion installation opening  125  is connected by the second locking portion installation hole  134  of the detergent case bracket  130  coupled from the front, so that a second locking portion  223  of the second locking member  220  may be exposed or non-exposed. 
     The detergent case bracket  130  may be provided between the detergent case cover  140  and the detergent case body  121 . The detergent case cover  140  may be coupled to the front surface of the detergent case bracket  130 . 
     The detergent case bracket  130  may be provided with a second locking portion installation portion  150  for installing the second locking device  200 . The second locking portion installation portion  150  may be provided in front of the detergent case bracket  130 . 
     The second locking portion installation portion  150  may include a second locking member accommodating groove  151  formed to accommodate the second locking member  220 , a rotation shaft coupling portion  152  provided above the second locking member accommodating groove  151 , and a second locking portion through portion  153  through which at least a portion of the second locking member  220  penetrates and is rotatably installed. The second locking portion through portion  153  may be connected to the second locking portion installation hole  134 . 
     The detergent case cover  140  may be disposed in front of the second locking portion installation portion  150 . The second locking portion installation portion  150  may be covered by the detergent case cover  140  coupled to the front surface of the detergent case bracket  130 . The user may press the second locking member  220  through the handle  141  formed on the detergent case cover  140 . The user may rotate the second locking member  220  by pressing the second locking member  220  through the handle  141  formed on the detergent case cover  140 . 
     The second locking member  220  may include a pressing portion  221 , the second locking portion  223  extending from the pressing portion  221  to lock or unlock the first locking member  210 , and a rotation shaft  222  supporting the second locking portion  223  to be rotated by pressing of the pressing portion  221 . 
     The pressing portion  221  of the second locking member  220  may be disposed in rear of the handle  141  of the detergent case cover  140 . The pressing portion  221  may be provided to be gripped by the user through the handle  141  of the detergent case cover  140 . The pressing portion  221  may be formed in a shape and size corresponding to the second locking portion installation portion  150  of the detergent case bracket  130 . The pressing portion  221  may be provided to be accommodated in the second locking member accommodating groove  151 . The pressing portion  221  may be formed in a plate shape including a plurality of curved surfaces  221   a  to improve the user&#39;s manipulation texture. The pressing portion  221  is provided such that the user may pull the pressing portion  221  forward through the handle  141 . The rotation shaft  222  may be provided on the pressing portion  221 . The rotation shaft  222  may be formed at an upper end of the pressing portion  221 . The pressing portion  221  may be connected to the second locking portion  223  through the rotation shaft  222 . The second locking portion  223  may include a rotation arm  224  connected to the rotation shaft  222 . The rotation arm  224  may connect the rotation shaft  222  and the second locking portion  223 . When the pressing portion  221  is pressed forward by the user, the rotation arm  224  rotates about the rotation shaft  222  so that the second locking portion  223  is rotated in a downward direction. 
     When pressing of the pressing portion  221  is released by the user, the rotation arm  224  rotates about the rotation shaft  222  so that the second locking portion  223  is rotated in an upward direction. 
     The second locking member  220  may include an elastic member  300  for elastically supporting the detergent case  120 . The elastic member  300  may be disposed between the detergent case  120  and the second locking member  220 . The elastic member  300  elastically supports at least a portion of the detergent case  120  and the rotation arm  224  of the second locking member  220 , so that when the user releases the pressing of the pressing portion  221 , the rotation arm  224  may be rotated to an original position by the elastic member  300 . The disclosure illustrates that the elastic member  300  supports the rotation arm  224  and the detergent case  120 , but is not limited thereto. Also, the disclosure illustrates that the elastic member  300  is a leaf spring, but is not limited thereto. For example, the elastic member  300  may include a coil spring. 
     The second locking portion  223  of the second locking member  220  may be provided to be locked to or unlocked from the first locking member  210 . 
     The first locking member  210  may include a first locking portion  211 . The first locking portion  211  may be provided to correspond to the second locking portion  223  so that the second locking portion  223  may be locked or unlocked. The first locking portion  211  may be formed to be in contact with the second locking portion  223 . The first locking portion  211  may be disposed on at least a portion of the main body  10 . The first locking portion  211  may protrude forward from the detergent case cover installation surface  61  of the front panel  20 . The first locking portion  211  may be formed at a position corresponding to the second locking portion installation opening  125  and the second locking portion installation hole  134  of the detergent case  120 . The first locking portion  211  may include a first locking surface  212  having a first angle θ 1 . The first locking surface  212  may be formed on a rear surface of the first locking portion  211 . The first locking surface  212  may be disposed such that the second locking portion  223  may come into contact therewith. 
     The first angle θ 1  of the first locking surface  212  may be formed at 90°+α. 
     The second locking portion  223  may include a second locking surface  226  provided to correspond to the first locking surface  212  and having an inclination of a second angle θ 2 . The second locking portion  223  may extend from the rotation arm  224  and may be bent upward from an end of the rotation arm  224 , The disclosure illustrates that the second locking portion  223  is formed in a hook shape, but is not limited thereto. 
     The second locking surface  226  may be formed on at least one surface of the second locking portion  223 . The second locking surface  226  may be formed on a front surface of the second locking portion  223 . The second locking surface  226  may be provided to correspond to the first locking surface  212 . The second angle θ 2  of the second locking surface  226  may be greater than or equal to the first angle θ 1 . The second angle  82  of the second locking surface  226  may be formed at 90°+β. β may be greater than or equal to α. α may be 0 to 0.5 degree. 
     Because the second locking surface  226  of the second locking member  220  that is locked to the first locking surface  212  of the first locking member  210  has the inclination of the second angle θ 2  greater than or equal to the first angle θ 1 , release of the locking between the first locking member  210  and the second locking member  220  that occurs due to the vibration caused by washing or dehydrating operation of the washing machine  1  is prevented. 
     Conversely, when the user presses the pressing portion  221  of the second locking member  220  with a slight force, the second locking portion  223  may rotate about the rotation shaft  222  to release the locking between the first locking surface  212  and the second locking surface  226 . 
       FIG.  8    illustrates the detergent case when the locking device is in a closing position according to an embodiment of the disclosure,  FIG.  9    is an enlarged view of a portion C in  FIG.  8   , illustrating a locking operation of the locking device according to an embodiment of the disclosure,  FIG.  10    illustrates the detergent case when the locking device is in an openable position according to an embodiment of the disclosure, 
       FIG.  11    is an enlarged view of a portion D in  FIG.  10   , illustrating an opening operation of the locking device according to an embodiment of the disclosure,  FIG.  12    illustrates the detergent case when the locking device is in an unlocking position according to an embodiment of the disclosure, and  FIG.  13    is an enlarged view of a portion E in  FIG.  12   , illustrating an unlocking operation of the locking device according to an embodiment of the disclosure. Reference numerals not shown in the above drawings may be described with reference to  FIGS.  1  to  7   . 
     As illustrated in  FIGS.  8  to  13   , the locking/unlocking state between the detergent case  120  and the main body  10  by the locking device  200  will be described. 
     As illustrated in  FIGS.  8  and  9   , when the detergent case  120  is completely inserted into the detergent supply device installation portion  60  of the main body  10 , the locking device  200  is in a locking state. The first locking member  210  and the second locking member  220  of the locking device  200  are locked to each other. 
     The first locking portion  211  of the first locking member  210  disposed on the detergent supply device installation portion  60  of the front panel  20  may protrude forward from the detergent case cover installation surface  61 . The first locking surface  212  is formed on the rear surface of the first locking portion  211 . 
     The second locking portion  223  of the second locking member  220  disposed in the detergent case  120  may be installed to protrude from the inside of the detergent case  120  to the outside. The second locking portion  223  may be provided to protrude through the second locking portion installation opening  125  of the detergent case  120 . The second locking portion  223  may include the second locking surface  226  corresponding to the first locking surface  212  of the first locking portion  211 . The second locking surface  226  may correspond to the first locking surface  212 . The second locking surface  226  may be in contact with the first locking surface  212 . 
     When the second locking surface  226  is in a locked state of being in contact with the first locking surface  212 , the detergent case  120  is positioned in a completely dosed position in the main body  10 . When the detergent case  120  is in the dosed state in the detergent supply device installation portion  60  of the main body  10 , the pressing portion  221  of the second locking member  220  is disposed to be spaced apart from an inner surface of the detergent case cover  140  by a predetermined distance. In this case, the rotation shaft  222  of the second locking member  220  positions the pressing portion  221  at a third angle θ 3 . The third angle θ 3  may be 3.5 degrees. In this case, the second locking surface  226  of the second locking member  220  may be positioned on the first locking surface  212  in an inclined state at a fourth angle θ 4  from the rotation shaft  222 , The fourth angle θ 4  may be 4.5 degrees. 
     When the first locking portion  211  and the second locking portion  223  of the locking device  200  are in the locked state, the locking between the first locking surface  212  and the second locking surface  226  is not released even when vibration occurs by washing or dehydrating operation of the washing machine  1 , so that the detergent case  120  may be prevented from being opened. 
     As illustrated in  FIGS.  10  to  13   , in order to separate the detergent case  120  from the detergent supply device installation portion  60  of the main body  10 , the locking device  200  becomes in an unlocked state. 
     In order to separate the detergent case  120  from the main body  10 , the first locking member  210  and the second locking member  220  of the locking device  200  may be opened by being unlocked with each other. 
     In order to open the detergent case  120  from the detergent supply device installation portion  60  of the main body  10 , as illustrated in  FIGS.  10  and  11   , the pressing portion  221  of the second locking member  220  may be rotated forward (an arrow direction P) at a predetermined angle from an initial state of the locking device  200  by pressing of the user. The pressing portion  221  may be rotated about the rotation shaft  222 . 
     The pressing portion  221  of the second locking member  220  is disposed to be spaced apart from the inner surface of the detergent case cover  140  by the predetermined distance. At this time, the rotation shaft  222  of the second locking member  220  positions the pressing portion  221  at a fifth angle θ 5 . The fifth angle θ 5  may be 1.0 degree. In this case, the second locking surface  226  of the second locking member  220  may be positioned on the first locking surface  212  in an inclined state at the fifth angle θ 5  from the rotation shaft  222 . The fifth angle  85  may be 1.0 degree. 
     As illustrated in  FIGS.  12  and  13   , the user may further rotate the pressing portion  221  of the second locking member  220  to separate the second locking member  220  from the first locking member  210 . 
     The user may further press the pressing portion  221  forward to come into contact with the inner surface of the detergent case cover  140 . The pressing portion  221  may be rotated about the rotation shaft  222  until the pressing portion  221  comes into contact with the inner surface of the detergent case cover  140 . At this time, the second locking surface  226  may be positioned to be spaced apart from the first locking surface  212  by a predetermined distance g. 
     As the second locking portion  223  is positioned to be spaced apart from the first locking portion  211  by the predetermined distance g, the first locking member  210  and the second locking member  220  are not in contact with or interfered with each other and may allow the detergent case  120  to be moved. 
     Accordingly, the user may release the locking device  200  between the detergent case  120  and the main body  10  by pulling the pressing portion  221  through the handle  141  of the detergent case cover  140 , with a force required to open the detergent case  120 , which is smaller than a force required to press the pressing portion  221 , so that the detergent case  120  may be opened and closed without feeling of resistance, thereby improving usability. 
     As is apparent from the above, according to an embodiment of the disclosure, a locking structure of a detergent case can be improved to facilitate the withdrawal and entry of the detergent case. 
     In addition, the usability of a user can be improved by making a force for opening and dosing the detergent case constant. 
     While the disclosure has been particularly described with reference to exemplary embodiments, it should be understood by those of skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the disclosure.