[0001]    This application claims priority from Korean Patent Application No. 10-2007-0089504 filed on Sep. 4, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a laundry treatment machine and a door switch thereof, and more particularly, to a laundry treatment machine and a door switch thereof, which contributes to the improvement of the durability and the safety of a laundry treatment machine by preventing the infiltration of water into a switch housing unit. 
         [0004]    2. Description of the Related Art 
         [0005]    Laundry treatment machines are classified into washing machines removing dirt or dust from clothes or bedclothes by using water and detergent and using mechanical operations, dryers drying wet laundry by using a dry, hot wind generated by a heater and using mechanical operations, and combination washer dryers performing both a washing function and a drying function. 
         [0006]    Drum-type washing machines, which are one type of washing machine, include a cabinet, a tub installed in the cabinet and holding wash water, and a drum installed in the tub and holding laundry. 
         [0007]    The cabinet includes a cabinet main body which is open at the top and the front of the cabinet main body, a top cover which is installed on top of the cabinet main body, and a front panel which is installed at the front of the cabinet main body and has a laundry inlet/outlet hole formed at the front of the front panel. A door is connected to the front panel  8  by a hinge so as to open or close the laundry inlet/outlet hole. A door switch is provided on the front panel and determines whether the door is open or closed. The door switch includes a pressing pin which can be pressed by the door, and a switch housing unit which is connected to the pressing pin and includes a contact terminal. 
         [0008]    Conventionally, water flown along the front panel is highly likely to infiltrate into the switch housing unit during a water leak test or during a typical washing operation. If water infiltrates into the switch housing unit, the contact terminal of the switch housing unit may be short-circuited, the door switch may malfunction due to an increase in voltage, and safety accidents may occur. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a laundry treatment machine and a door switch thereof, which contributes to the improvement of the durability and the safety of a laundry treatment machine by preventing the infiltration of water into a switch housing unit. 
         [0010]    According to an aspect of the present invention, there is provided a door switch of a laundry treatment machine, the door switch including a switch contact unit which penetrates through a cabinet, is exposed at the front of the cabinet, and may or may not be placed in contact with a door according to whether the door is open or closed; a switch housing unit which is connected to the switch contact unit and is installed in the cabinet; and a water infiltration prevention unit which isolates the switch housing unit from the cabinet so that the switch housing unit and the cabinet can be a predetermined distance apart from each other, the water infiltration prevention unit preventing the infiltration of water flown along the cabinet into the switch housing unit. 
         [0011]    The water infiltration prevention unit may include a coupler coupled to the cabinet and a plurality of connectors connecting the coupler and the switch housing unit. 
         [0012]    The cabinet may include a switch hole and the coupler may be coupled to the cabinet by being inserted into the switch hole. 
         [0013]    The coupler may be inserted into the switch hole in the direction of front and rear of the cabinet, and may be disposed at the front of the cabinet. 
         [0014]    The coupler may be inserted into the switch hole in the direction of front and rear of the cabinet, and may be formed as a panel that covers the switch hole. 
         [0015]    The connectors may include a plurality of ribs protruding from the switch housing unit toward the coupler and the ribs may be evenly spaced apart from one another. 
         [0016]    The cabinet and the switch housing unit may be hook-coupled to each other. 
         [0017]    The door switch may also include a mounting bracket, which is installed in the cabinet and is hook-coupled to the switch housing unit. 
         [0018]    One of the switch housing unit and the mounting bracket may include a hook protruding therefrom, and the other one of the switch housing unit and the mounting bracket may include an engaging protrusion engaging with the hook. 
         [0019]    According to another aspect of the present invention, there is provided a door switch of a laundry treatment machine, the door switch including a switch contact unit which penetrates through a cabinet, is exposed at the front of the cabinet, and may or may not be placed in contact with a door according to whether the door is open or closed; a switch housing unit which is connected to the switch contact unit and is installed in the cabinet; and a water infiltration prevention unit which isolates the switch housing unit from the cabinet so that the switch housing unit and the cabinet can be a predetermined distance apart from each other, the water infiltration prevention unit including a discharge unit and preventing the infiltration of water flown between the cabinet and the switch housing unit into the switch housing unit by discharging the water through the discharge unit. 
         [0020]    According to another aspect of the present invention, there is provided a laundry treatment machine including a cabinet in which a tub and a drum are disposed, the cabinet including a laundry inlet/outlet hole formed at the front of the cabinet; a door which opens or closes the laundry inlet/outlet hole; a switch contact unit which penetrates through a cabinet, is exposed at the front of the cabinet, and may or may not be placed in contact with a door according to whether the door is open or closed; a switch housing unit which is connected to the switch contact unit and is installed in the cabinet; and a water infiltration prevention unit which isolates the switch housing unit from the cabinet so that the switch housing unit and the cabinet can be a predetermined distance apart from each other, the water infiltration prevention unit preventing the infiltration of water flown along the cabinet into the switch housing unit. 
         [0021]    The water infiltration prevention unit may include a coupler coupled to the cabinet and a plurality of connectors connecting the coupler and the switch housing unit. 
         [0022]    The cabinet may include a switch hole and the coupler may be coupled to the cabinet by being inserted into the switch hole. 
         [0023]    The coupler may be inserted into the switch hole in the direction of front and rear of the cabinet, and may be disposed at the front of the cabinet. 
         [0024]    The coupler may be inserted into the switch hole in the direction of front and rear of the cabinet, and may be formed as a panel that covers the switch hole. 
         [0025]    The connectors may include a plurality of ribs protruding from the switch housing unit toward the coupler and the ribs may be evenly spaced apart from one another. 
         [0026]    The cabinet and the switch housing unit may be hook-coupled to each other. 
         [0027]    The door switch may also include a mounting bracket, which is installed in the cabinet and is hook-coupled to the switch housing unit. 
         [0028]    One of the switch housing unit and the mounting bracket may include a hook protruding therefrom, and the other one of the switch housing unit and the mounting bracket may include an engaging protrusion engaging with the hook. 
         [0029]    In short, the switch housing unit is a predetermined distance apart from the cabinet. Thus, water flown along the cabinet may be able to be discharged through the space between the cabinet and the switch housing unit. Therefore, it is possible to minimize the infiltration of water into the switch housing unit and to improve the durability and the safety of the door switch. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The above and other features and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which: 
           [0031]      FIG. 1  illustrates a perspective view of a drum-type washing machine according to an exemplary embodiment of the present invention; 
           [0032]      FIG. 2  illustrates a cross-sectional view of a door switch shown in  FIG. 1 ; and 
           [0033]      FIG. 3  illustrates a lateral view of the door switch shown in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0034]    The present invention will hereinafter be described in detail with reference to the accompanying drawings in which exemplary embodiments of the invention are shown, and taking a drum-type washing machine as an example of a laundry treatment machine. 
         [0035]      FIG. 1  illustrates a perspective view of a drum-type washing machine according to an exemplary embodiment of the present invention. Referring to  FIG. 1 , the drum-type washing machine includes a cabinet, which forms the exterior of the drum-type washing machine, a tub (not shown), which is installed in the cabinet and holds wash water, and a drum  2 , which is installed in the tub and holds laundry. 
         [0036]    The cabinet includes a cabinet main body  4 , which is open at the top or the front of the cabinet main body  4 , a top cover  6 , which is installed so as to cover the top of the cabinet main body  4 , and a front panel  8 , which is installed so as to cover the front of the cabinet main body  4  and has a laundry inlet opening through which laundry is placed into the drum-type washing machine. 
         [0037]    A control panel  10  is installed on one side of an upper portion of the front panel  8  and displays various information regarding the operating state of the drum-type washing machine. A detergent container  12  is installed on the other side of the upper portion of the front panel  8  and contains detergent. 
         [0038]    A door  14  is installed on the front panel  8  by a hinge so as to open or close the laundry inlet/outlet hole. A door switch  20  is provided on the front panel  8  and determines whether the door  14  is open or closed. 
         [0039]      FIG. 2  illustrates a cross-sectional view of the door switch  20  shown in  FIG. 1 , and  FIG. 3  illustrates a lateral view of the door switch  20  shown in  FIG. 2 . Referring to  FIGS. 2 and 3 , the door switch  20  includes a switch contact unit  22 , which may or may not be placed in contact with the door  14  according to whether the door  14  is open or closed, a switch housing unit  24 , which is connected to the switch contact unit  22 , and a water infiltration prevention unit, which prevents the infiltration of water into the switch housing unit  24  by isolating the switch housing unit  24  from the front panel  8  so that the switch housing unit  24  from the front panel  8  can be a predetermined distance apart from each other. 
         [0040]    The switch contact unit  22  protrudes from the switch housing unit  24  toward the door  14 . The switch contact unit  22  may be implemented as a pressing pin that can be pressed by the door  14 . 
         [0041]    The switch housing unit  24  may be formed of a plastic material through injection molding. A number of electric elements such as terminals may be installed in the switch housing unit  24 . 
         [0042]    The water infiltration prevention unit includes a coupler  26 , which is coupled to the front panel  8 , and a plurality of connectors  28 , which connect the coupler  26  and the switch housing unit  24 . 
         [0043]    The coupler  26  may be formed as a panel. The coupler  26  may be inserted into a switch hole (not shown) in the direction of front and rear of the cabinet on the front panel  8 , and may be disposed at the front of the front panel  8 . The coupler  26  may cover the switch hole. 
         [0044]    The connectors  28  may be formed as ribs that protrude from the switch housing unit  24  toward the coupler  26 . The connectors  28  may be evenly spaced apart from one another, and thus, a space s may be provided between the connectors  28 . The spaces s may serve to prevent water from accumulating between the front panel  8  and the switch housing unit  24  by permitting water to flow there between. 
         [0045]    A mounting bracket  34  is installed on the front panel  8 , and is coupled to the switch housing unit  24 . The mounting bracket  34  has a hole in the middle. The hole of the mounting bracket  34  corresponds to the switch hole. First and second engaging protrusions  34   a  and  34   b  are formed on either side of the hole of the mounting bracket  34 . 
         [0046]    The mounting bracket  34  and the switch housing unit  24  may be hook-coupled to each other by using a hook  30  and an engaging jaw  32 . More specifically, the hook  30  protrudes from one side of the switch housing unit  24 , and the engaging jaw  32  protrudes from the other side of the switch housing unit  24 . The hook  30  may extend long enough to have elasticity. 
         [0047]    The hook  30  may be coupled to the first engaging protrusion  34   a , and the engaging jaw  32  may engage with the second engaging protrusion  34   b.    
         [0048]    The operation of the door switch  20  will hereinafter be described in detail. 
         [0049]    Laundry is inserted into the drum  2 , and then the door  14  is closed. Thereafter, the drum-type washing machine is driven by manipulating the control panel  10 . 
         [0050]    When the door  14  is closed, the door  14  presses the switch contact unit  22 . If the switch contact unit  22  is pressed, the switch housing unit  24  may determine that the door  14  is closed. 
         [0051]    If a liquid such as water flows toward the front panel  8  by accident or on purpose as part of a water leak test, the water may either flow downward along the front panel  8  or may flow through the spaces  6  between the connectors  28  away from the door switch  20 . 
         [0052]    Since the switch housing unit  24  is isolated from the front panel  8 , it is possible to prevent the infiltration of water into switch housing unit  24  even when water flows along the front panel  8 . 
         [0053]    Even when water flows between the front panel  8  and the switch housing unit  24 , the water is discharged through the spaces s, and thus, it is possible to prevent the infiltration of water into switch housing unit  24 . 
         [0054]    While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
A laundry treatment machine and a door switch thereof are provided. The door switch includes a switch housing unit, which is a predetermined distance apart from a cabinet. Thus, water flown along the cabinet may be able to be discharged through the space between the cabinet and the switch housing unit. Therefore, it is possible to minimize the infiltration of water into the switch housing unit and to improve the durability and the safety of the door switch.