Patent Publication Number: US-10763058-B2

Title: Switch device comprising two switches which share a common conductor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation Application of U.S. patent application Ser. No. 16/133,852 filed Sep. 18, 2018, which claims the priority of Korean Patent Application No. 10-2017-0122449, filed in Korea on Sep. 22, 2017 and Korean Patent Application No. 10-2017-0161027, filed in Korea on Nov. 28, 2017, in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     A switch device and a cooking appliance including a switch device are disclosed herein. 
     2. Background 
     Electric switches with rotatable rotors may be used in a variety of applications in a variety of cooking appliances. For example, an electrical switch with a rotatable rotor may be used as a switch to control a burner ignition-circuit in a cooking appliance that uses gas as fuel. 
     The electrical switch for the cooking appliance may be installed in a manner such that it is coupled to a valve stem rotatably connected to a gas valve. The rotor of the electrical switch may be rotated together with the valve stem which is rotated when a knob connected to the valve stem is rotated. 
     When the valve stem is rotated to open the valve to activate gas supply, the burner ignition-circuit is activated to ignite the gas supplied to the burner. With this configuration, the rotor of the electrical switch is rotated together with the valve stem. The electrical switch allows rotation of the rotor to be involved in activation of the burner ignition-circuit. 
     Typically, the electrical switch used as a switch for controlling the burner ignition-circuit of the cooking appliance includes a rotor in the form of a cam and a pair of contact blades. In this case, when the pair of contact blades are separated from each other, the burner ignition-circuit may be inactivated. When the pair of contact blades touch each other, the burner ignition-circuit may be activated. 
     When the valve stem is rotated to open the valve, the rotor is rotated together with the valve stem to allow the pair of contact blades in a non-contact state to contact each other. With this configuration, an electrical connection between the pair of the contact blades may be achieved by pressing one of the pair of contact blades so that contact is made between the pair of contact blades. 
     An electrical switch with this configuration may be used for only a single circuit. When various circuits are used in order to provide various functions, a plurality of electric switches is required for switching various circuits respectively. 
     In order to improve the safety of the cooking appliance and to enhance the user&#39;s convenience, the cooking appliance in which the electric switch is used may require a multi-switching function by which various circuits are switched via actuation of a same rotational axis. For example, when an indicator for indicating that the valve is open is provided on the cooking appliance, the user may easily know from the indicator light that the valve is open. The turn-on and turn-off of the indicator will be closely related to the opening or closing of the valve. Therefore, switching of the circuit for turn-on and turn-off of the indicator is preferably performed via the rotation of the valve stem. 
     That is, in the cooking appliance, a multi-switching function may be required in which the switching of the burner ignition-circuit and the switching of the turn-on/off circuit of the indicator lamp are performed together with the rotation of the valve stem. 
     However, in order to realize the multi-switching function by using the electric switch as described above, a first electric switch for switching the burner ignition-circuit and a second electric switch for switching the turn-on/off circuit of the indicator lamp are separately required. That is, in order to implement the multi-switching function using the above-described electric switch, the number of electric switches to be installed in the cooking operation must be increased as the number of circuits to be subjected to the switching operation increases. This increases a number of wires connected to a switch, complicates a structure of the switch, increases an overall volume of the switch, and increases manufacturing costs of a cooking appliance in which the switch is installed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein: 
         FIG. 1  is a perspective view of a cooking appliance according to an embodiment; 
         FIG. 2  is an exploded perspective view schematically illustrating the cooking appliance shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of a switch device according to an embodiment; 
         FIG. 4  is a perspective view showing an internal structure of the switch device as shown in  FIG. 3 ; 
         FIG. 5  is a perspective view showing an internal structure of a housing shown in  FIG. 4 ; 
         FIG. 6  is a perspective view of a separated state of each of a first blade and a second blade shown in  FIG. 4 ; 
         FIG. 7  is a cross-sectional view, taken along line VII-VII of  FIG. 4 ; 
         FIG. 8  shows an operating state of a second switch of the switch device as shown in  FIG. 4 ; 
         FIG. 9  shows operating states of a first switch and a second switch of the switch device as shown in  FIG. 4 ; 
         FIG. 10  is a perspective view showing an internal structure of a switch device according to another embodiment; 
         FIG. 11  shows an operating state of a second switch of the switch device as shown in  FIG. 10 ; 
         FIG. 12  shows operating states of a first switch and a second switch of the switch device as shown in  FIG. 10 ; 
         FIG. 13  is a perspective view showing an internal structure of a switch device according to another embodiment; 
         FIG. 14  shows an operating state of a second switch of the switch device as shown in  FIG. 13 ; 
         FIG. 15  shows operating states of a first switch and a second switch of the switch device as shown in  FIG. 13 ; 
         FIG. 16  is a perspective view showing an internal structure of a switch device according to another embodiment; 
         FIG. 17  is a cross-sectional view, taken along line XVII-XVII of  FIG. 16 ; 
         FIG. 18  is a perspective view showing an internal structure of a switch device according to another embodiment; 
         FIG. 19  is a cross-sectional view, taken along line XIX-XIX of  FIG. 18 ; 
         FIG. 20  is a perspective view of a switch device according to another embodiment; 
         FIG. 21  is a bottom perspective view showing an internal structure of the switch device as shown in  FIG. 20 ; 
         FIG. 22  is a bottom view showing the internal structure of the switch device as shown in  FIG. 21 ; and 
         FIG. 23  is an exploded perspective view showing an actuator of the switch device as shown in  FIG. 21 . 
     
    
    
     DETAILED DESCRIPTION 
     Examples of various embodiments are illustrated and described further below. It will be understood that the description herein is not intended to limit the claims to the specific embodiments described. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the present disclosure as defined by the appended claims. 
     The same reference numbers in different figures may denote the same or similar elements, and as such may perform similar functionality. Further, descriptions and details of well-known steps and elements are omitted for simplicity of the description. Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding. However, it will be understood that embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects. 
     It will be understood that, although the terms “first”, “second”, “third”, and so on may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section described below could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the present disclosure. 
     It will be understood that when an element or layer is referred to as being “connected to”, or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. In addition, it will also be understood that when an element or layer is referred to as being “between” two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present. 
     The terminology used herein is for describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise”, “comprising”, “include”, and “including” when used in this specification, specify the presence of the stated features, integers, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and/or portions thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expression such as “at least one of” when preceding a list of elements may modify the entire list of elements and may not modify the individual elements of the list. 
     Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIG. 1  is a perspective view of a cooking appliance according to an embodiment.  FIG. 2  is an exploded perspective view schematically illustrating the cooking appliance shown in  FIG. 1 . 
     Referring to  FIG. 1  and  FIG. 2 , a cooking appliance according to an embodiment may include a body  1  defining an appearance thereof. The body  1  may be formed in a substantially rectangular parallelepiped shape. The body  1  may be made of a material having a predetermined strength to protect a plurality of components installed in an inner space thereof. 
     On a top of the body  1 , a cook-top unit or cook-top  2  may be provided to heat food or other items (hereinafter “food”) placed on a top thereof, or a container containing the food therein disposed thereon to cook the food. The cook-top  2  may include a loading plate  3  that supports food to be cooked, or a container containing the food. The loading plate  3  may define a top portion of the cook-top  2 . 
     The container containing food or food to be cooked may be loaded on the loading plate  3 . Below the loading plate  3 , at least one burner  90  may be provided that heats the container containing the food or food to be cooked. 
     Below the cook-top  2 , an oven unit or oven  4  may be provided. In an interior space of the oven  4 , a cooking chamber  5  defining a food cooking space may be disposed. The cooking chamber  5  may have a hexahedral shape with an open front. When a front face of the cooking chamber  5  is blocked or closed, the interior space in the cooking chamber  5  may be heated to cook the food. That is, the interior space in the cooking chamber  5  in the oven  4  may serve as a space where food is cooked. 
     An upper heater may be provided above the cooking chamber  5  so as to supply heat downward toward the interior space of the cooking chamber  5 . Below the cooking chamber  5 , a lower heater may be provided which applies heat upwards towards the interior space of the cooking chamber  5 . 
     Further, a convection unit that heats the interior space of the cooking chamber  5  via convection of hot air may be provided at a rear of the cooking chamber  5 . The convection unit may heat the air in the interior space of the cooking chamber  5  and forcibly cause the heated air to flow so as to heat the interior space of the cooking chamber  5 . This ensures that the food located in the interior space of the cooking chamber  5  is heated uniformly. 
     The oven  4  may include a door  6  that selectively opens and closes the cooking chamber  5 . The door  6  may be pivotably provided. 
     The door  6  may have a generally hexahedral shape with a predetermined thickness. A handle  7  may be mounted on the door  6 . A user may grasp the handle  6  when the user wishes to pivot the door  6 . By using the handle  7 , the user may easily pivot the door  6 . 
     A control panel  8  may be provided on or at a front of the cook-top  2 , and above the door  6 . On the control panel  8 , there may be disposed a plurality of knobs  10 , which may be manipulated by a user, to control ignition and thermal power of each burner  90 . Each knob  10  may operate via rotation by the user around an axis of rotation which may be a central axis thereof. However, an operation scheme of the knob is not limited to the rotation type. 
     In this embodiment, five burners  90  are provided. Correspondingly, an example in which five knobs  10  and five valves  40  are respectively provided is illustrated. Each of the five knobs  10  as shown in  FIG. 1  may being fixedly fitted with a rotational shaft  50  of the valve  40  passing through the control panel  8 . When the knob  10  is rotated, the rotational shaft  50  may rotate together with the knob  10 . In this way, whether or not the valve  40  is opened and closed, and a degree of opening thereof may be determined. 
     Within the control panel  8 , the rotational shaft  50  may be inserted into a switch device  100 . An example of the structure of the switch device  100  will be described hereinafter. 
     The cook-top  2  may accommodate therein a gas input pipe  94  a first end of which may be connected to an external gas pipe to supply gas to each burner  90 . A second end of the gas input pipe  94  may be connected to a gas distribution pipe  96 . A governor valve  80  may be provided at the gas input pipe  94  to control whether the gas is to be supplied to the cook-top  2 . In  FIG. 2 , the governor valve  80  is shown to be positioned at the second end of the gas input pipe  4 . However, the position of the governor valve is not necessarily limited thereto. 
     The gas distribution pipe  96  may be connected to all of first connectors  41  of the valves  40 . The gas supplied from the gas input pipe  94  may be supplied from the gas distribution pipe  96  to each of the valves. A second connector  42  of the valve  40  may be connected to a first end of an individual pipe  98 . A second end of the individual pipe  98  may be connected to a corresponding burner  90 . 
     A control unit or controller  9  may be equipped with electrical components that control operations of the oven  4  and cook-top  2  and control power supply thereto and display operation information thereof. 
       FIG. 3  is a perspective view of a switch device according to an embodiment.  FIG. 4  is a perspective view showing an internal structure of the switch device as shown in  FIG. 3 . 
     Referring to  FIG. 3  and  FIG. 4 , the switch device  100  according to this embodiment may include a housing  110 , a first switch  120 , a second switch  130 , and an actuator  140 . The housing  110  may define the appearance of the switch device  100 . The housing  110  may have a receiving space defined therein for receiving the first switch  120 , the second switch  130 , and the actuator  140  therein. 
     In this embodiment, an example in which the housing  110  has a flat rectangular parallelepiped shape is illustrated. The housing  110  may include a combination of a first housing  110   a  and a second housing  110   b , which may be removably assembled and arranged in a vertical direction. Further, the first housing  110   a  and the second housing  110   b  each may include a rectangular bottom face  111  and a sidewall  113  that extends upwardly from an outer edge of the bottom face  111  and surrounds the bottom face  111 . The second housing  110   b  may be coupled to an open top of the first housing  110   a  to cover the open top of the first housing  110   a . In this way, the receiving space may be defined. 
     Further, a central hole  112  may be formed in a central region of the bottom face  111 . The actuator  140 , which will be described hereinafter, may be installed at the central region of the bottom face  111  in which the central hole  112  is formed therein. 
     Conductors  150 ,  155 ,  160 , and  165  may be laterally inserted in the housing  110 . Each of the conductors  150 ,  155 ,  160 , and  165  may include a core conductive wire of a highly conductive metal and an insulating cover material covering the conductive wire. Each of the conductors  150 ,  155 ,  160 , and  165  may laterally penetrate the sidewall  113  of the housing  110 . 
     The housing  110  may have a single inner space defined therein. The conductors  150 ,  155 ,  160 , and  165  may extend through the single inner space of the housing  110 . The conductors  150 ,  155 ,  160 , and  165  may share the single inner space. The conductors  150 ,  155 ,  160 , and  165  may be connected to the first switch  120  and the second switch  130 , respectively, in the single inner space. 
     In this embodiment, an example in which four conductors  150 ,  155 ,  160 , and  165  are installed in one switch device  100  is illustrated. In this example, a pair of common conductors  150  and  155 , a first conductor  160 , and a second conductor  165  are installed in the switch device  100  so as to pass through the single internal space of the housing  110 . 
     In one example, around the central region of the bottom face  111  where the actuator  140  is installed, one of a pair of common conductors  150  and  155 , that is, a first common conductor  150  and a first conductor  160  may be disposed at one or a first side of a first directional (Y) side. Further, the other or a second of the pair of common conductors  150  and  155 , that is, the second common conductor  155  and the second conductor  165  may be disposed at the other or a second side of the first directional (Y) side. 
     That is, the actuator  140  may be disposed between a set of the first common conductor  150  and the first conductor  160  and a set of the second common conductor  155  and the second conductor  165 . The first common conductor  150 , the first conductor  160 , the second common conductor  155 , and the second conductor  165  may be arranged along a first direction, that is, the Y direction. Each of the first common conductor  150 , the first conductor  160 , the second common conductor  155 , and the second conductor  165  may extend in a second direction, that is, the X direction. 
     The first switch  120  may include a first blade  121  and a second blade  123  which may be installed inside the housing  110  and separated from each other. The first switch  120  may be opened or closed based on contact or non-contact between the first blade  121  and the second blade  123 . For example, the first switch  120  may be closed when contact is made between the first blade  121  and the second blade  123 . When the first blade  121  and the second blade  123  are not in contact with each other, the first switch  120  may be opened. 
     One of the first blade  121  or the second blade  123  may be connected to the first common conductor  150 , while the other of the first blade  121  or the second blade  123  may be connected to the first conductor  160 . In this embodiment, an example is illustrated in which the first blade  121  is connected to the first common conductor  150  and the second blade  123  is connected to the first conductor  160 . 
     The second switch  130  may include a third blade  131  and a fourth blade  133  disposed inside the housing  110  and separated from each other. The second switch  130  may be opened or closed based on contact or non-contact between the third blade  131  and the fourth blade  133 . For example, the second switch  130  may be closed when contact is made between the third blade  131  and the fourth blade  133 . The second switch  130  may be opened when the third blade  131  and the fourth blade  133  are not in contact with each other. 
     One of the third blade  131  or the fourth blade  133  may be connected to the second common conductor  155 , while the other of the third blade  131  or the fourth blade  133  may be connected to the second conductor  165 . In this embodiment, an example is shown in which the third blade  131  is connected to the second common conductor  155  and the fourth blade  133  is connected to the second conductor  165 . 
     The actuator  140  may be installed in the housing  110  to selectively open and close the first switch  120  and the second switch  130 . The actuator  140  may include a rotatable body  141 , a first protrusion  143 , and a second protrusion  145 . The rotatable body  141  may be formed in a substantially cylindrical shape and be rotatably installed in the central region of the bottom face  111  having the central hole  112  formed therein. 
     The first protrusion  143  may be formed to protrude from the rotatable body  141 . The first protrusion  143  may protrude from an outer circumferential surface of the rotatable body  141  toward the first switch  120 . The first protrusion  143  may be displaced in conjunction with rotation of the rotatable body  141 . The first protrusion  143  may press the first switch  120  at a position in contact with the first switch  120  such that the first blade  121  and the second blade  123  are in contact with each other. 
     According to this embodiment, as for the first switch  120 , the second blade  123  may be positioned closer to the actuator  140  than the first blade  121 . Further, the second blade  123  may be positioned such that at least a portion of the second blade  123  is within a displacement range of the first protrusion  143 . That is, as viewed from the open top of the first housing  110   a  toward the bottom face of the first housing  110   a , the second blade  123  may extend along a region between an outer surface of the rotatable body  141  and an end of the first protrusion  143  protruding therefrom. 
     When the first blade  121  and the second blade  123  are positioned in this manner, the first protrusion  143  may be displaced via rotation of the rotatable body  141  to contact the first switch  120  and contact the second blade  123  and press the second blade  123  toward the first blade  121 . Then, when the second blade  123  presses against the first blade  121 , the contact between the second blade  123  and the first blade  121  is established. Thereby, electrical connection between the first blade  121  and the second blade  123  is made, such that the first switch  120  comes into a closed state. 
     Like the first protrusion  143 , the second protrusion  145  may be formed to protrude from the rotatable body  141 . The second protrusion  145  may protrude from the outer circumferential surface of the rotatable body  141  toward the second switch  130 . The second protrusion  145  may press the second switch  130  such that the third blade  131  and the fourth blade  133  in contact each other. 
     According to this embodiment, for the first switch  120 , the first blade  121  may be positioned closer to the actuator  140  than the second blade  123 . Further, for the second switch  130 , the third blade  131  may be positioned closer to the actuator  140  than the fourth blade  133 . 
     When the third blade  131  and the fourth blade  133  are positioned in this manner, the second protrusion  145  may be displaced to contact the second switch  130  via rotation of the rotatable body  141 . Then, the displaced second protrusion  145  may contact the third blade  131  and press the third blade  131  toward the fourth blade  133 . Then, the third blade  131  may be pressed toward the fourth blade  133 , such that the third blade  131  contacts the fourth blade  133 . This allows an electrical connection between the third blade  131  and the fourth blade  133  to bring the second switch  130  into a closed state. 
     The first protrusion  143  and the second protrusion  145  may be formed to have different shapes. For example, radial protrusion dimensions of the first protrusion  143  and the second protrusion  145  may be configured differently based on respective distances between the first protrusion  143  and the second protrusion  145  and the first and second switches  120  and  130 . Alternatively, contact positions or contact lengths between the first and second switches  120  and  130  and the first protrusion  143  and the second protrusion  145  respectively may be configured differently based on a degree of rotation of the actuator  140 . 
     In this embodiment, when viewed from the open top of the first housing  110   a  toward the bottom face of the first housing  110   a , the first switch  120  is positioned a greater distance from the actuator  140  than the second switch  130 . Thus, the radial protrusion dimension of the first protrusion  143  is greater than the radial protrusion dimension of the second protrusion  145 . With this configuration, the second protrusion  145  has a radially projecting dimension such that, upon displacement, the second protrusion  145  contacts the second switch  130  but not the first switch  120 . 
     Further, in this embodiment, an example in which a circumferential dimension of the first protrusion  143  is smaller than a circumferential dimension of the second protrusion  145  is illustrated. In this case, when rotation of the actuator  140  is performed, a contact region between the second protrusion  145  and the second switch  130  may be larger than a contact region between the first protrusion  143  and the first switch  120 . 
     In addition, the first protrusion  143  and the second protrusion  145  may be positioned at different levels along the vertical direction of the rotatable body  141 . That is, the first protrusion  143  and the second protrusion  145  may have different vertical distances from the bottom face  111  of the first housing  110   a.    
     In this embodiment, an example where the first protrusion  143  is positioned farther from the bottom face of the first housing  110   a  than the second protrusion  145  is exemplified. Accordingly, one of the first blade  121  or the second blade  123  which is disposed closer to the actuator  140  than the other may be positioned farther from the bottom face  111  of the first housing  110   a  than the third blade  131  and the fourth blade  133 . Hereinafter, a distance from the bottom face  111  of the first housing  110   a  is referred to as a vertical level. 
     Accordingly, a point of contact between the first protrusion  143  and the first switch  120  and a point of contact between the second protrusion  145  and the second switch  130  may be different from each other along the vertical direction of the rotatable body  141 . That is, at a level relatively closer to the bottom face  111  of the first housing  110   a , a first contact between the first protrusion  143  and the first switch  120  is made to open/close the first switch  120 . More specifically, the first contact may be made between the first protrusion  143  and the first blade  121 . On the other hand, at a level relatively far from the bottom face  111  of the first housing  110   a , there is a second contact between the second protrusion  145  and the second switch  130  for opening and closing the second switch  130 . More specifically, the second contact between the second protrusion  145  and the fourth blade  133  may be achieved. 
       FIG. 5  is a perspective view showing an internal structure of the housing shown in  FIG. 4 . Referring to  FIG. 4  and  FIG. 5 , the housing  110  has a support structure. The support structure is provided for securing the first switch  120  and the second switch  130  within the housing  110 . The support structure may protrude from the bottom face  111  of the housing  110 . 
     In this embodiment, an example is shown in which the support structure is formed on the bottom face  111  of the first housing  110   a . In another example, the support structure may be formed on the bottom face of the second housing  110   b . Hereinafter, an example in which the support structure is formed on the bottom face  111  of the first housing  110   a  is illustrated. However, embodiments are not be limited thereto. 
     According to this embodiment, the support structure may include support blocks  115  and slots  116 . The support blocks  115  may protrude from the bottom face  111  of the first housing  110   a . The support blocks  115  may be respectively disposed in the housing  110  at locations where contact between the first switch  120  and conductors  150  and  160  are made, and at locations where contact between the second switch  130  and the conductors  155  and  165  are made. Each support block  115  may have a generally rectangular parallelepiped shape; however, embodiments are not limited thereto. 
     The slots  116  may be respectively defined in support blocks  115 . Each slot may define a cut-out along the first direction Y in each block. A number of the slots  116  may be equal to a number of the blades to be fixed to the support blocks  115 . Each blade may be fixedly fitted in each slot  116 . At least one of the first to third blades  121  to  133  may be inserted into the slot  116  and fixed to the support block  115 . 
     In this embodiment, a pair of slots  116  is formed in each support block  115 . The slots  116  may be arranged along the second direction X and spaced from each other at a predetermined space. 
     With this configuration, the second direction X may be defined as a direction parallel to the direction in which the conductors  150  and  155 ,  160  and  165  extend through the interior space of the housing  110 . The first direction Y may be defined as a direction perpendicular to the second direction X on a plane parallel to the bottom face  111  of the first housing  110   a.    
     The support blocks  115  may have conductor-receiving grooves  117  defined therein respectively. The common conductors  150  and  155 , and the first conductor  160  and the second conductor  165  may be received in the conductor-receiving grooves  117  while passing through the support blocks  115 . 
     In this embodiment, in the support structure formed for the first switch  120 , a first pair of conductor-receiving grooves  117  are defined for receiving the first common conductor  150  and the first conductor  160 . In the support structure formed for the second switch  130 , a second pair of conductor-receiving grooves  117  are defined to accommodate the second common conductor  155  and the second conductor  165 . With this configuration, a pair of conductor-receiving grooves  117  formed in each support structure is arranged spaced apart along the first direction y. 
     In addition, notches  114  may be defined in the sidewall  113  of the housing  110 . The notches  114  may be defined through the sidewall  113 . The notches  114  may define passages through which the common conductors  150  and  155 , the first conductor  160 , and the second conductor  165  pass through the housing  110 . 
     According to this embodiment, a first long side wall of the four side walls defining the sidewall  113  has a number of notches  114  defined therein corresponding to the number of the conductors. The number of notches  114  corresponding to the number of conductors are defined in a second long side wall parallel to the first long side wall. 
     For example, four notches  114  may be defined in the first long side wall of the four side walls defining the sidewall  113 , while four notches  114  may be defined in the second long side wall parallel to the first long side wall. The conductors  150  and  155 ,  160  and  165  may pass through the notches  114  in the sidewall  113  of the housing  110  and pass through the interior space of the housing  110 . 
     The arrangement of the notches  114  in the sidewall  113  may be as follows: the notches  114  may be defined in a pair of first and second side walls parallel to each other, and thus, all of the conductors  150  and  155 ,  160  and  165  may pass through the single sidewall  113 . 
     That is, all the conductors  150  and  155 ,  160  and  165  may be disposed within a single inner space of the single housing through the single sidewall  113 . As a result, all of the blades  121 ,  123 ,  131 , and  133  connected to the conductors  150  and  155 ,  160  and  165  may be disposed in the single inner space of the single housing. 
       FIG. 6  is a perspective view showing a separated state of each of first blade and second blade shown in  FIG. 4 .  FIG. 7  is a cross-sectional view, taken along line VII-VII of  FIG. 4 . 
     Referring to  FIGS. 4 and 7 , at least one of the first blade  121  to the fourth blade  133  may include a blade body a, and a conductor-receiving portion b. In this embodiment, an example in which each of all of the blades  121 ,  123 ,  131 , and  133  includes a blade body a, and a conductor-receiving portion b is illustrated. 
     Hereinafter, structure of each of the first blade  121  and the second blade  123  is exemplarily discussed. 
     The blade body a may be made of a highly conductive metal material and have a length extending in the first direction Y. The blade body a may be fitted in the slots  116 , and thus, may be fixed to the support blocks  115 , and be installed so as to be exposed to outside of the support blocks  115 . 
     The conductor-receiving portion b may define one longitudinal direction end of the blade body a. When the blade body a is inserted in the slots  116  and is coupled to the support blocks  115 , the conductor-receiving portion b may be configured be located at one of the pair of conductor-receiving grooves  117  defined in the support structure. 
     The conductor-receiving portion b may have a slit defined therein. A corresponding one of the conductors  150  and  155 ,  160  and  165  may be inserted into the slit of the conductor-receiving portion b. Engagement between the conductor-receiving portion b and the corresponding one of the conductors  150  and  155 ,  160  and  165  may be achieved. With this configuration, the conductor-receiving portion b may penetrate the insulating coating of the corresponding one of the conductors  150  and  155 ,  160  and  165  and may be in contact with the conductive wire hidden inside the insulating coating. Thereby, electrical connection between the conductors  150  and  155 ,  160  and  165  and the blades  121 ,  123 ,  131  and  133  may be established. 
     In addition, the blade body a may have a non-interference groove c defined therein. The non-interference groove c may prevent a conductor passing through the conductor-receiving groove  117  among the common conductors  150  and  155  and the first conductor  160  and the second conductor  165  from being interfering with the blade body a. In this embodiment, an example in which each of the first and second blades  121  and  131  connected to the first common conductor  150  and the second common conductor  155 , which are located relatively far from the actuator  140  has the non-interference groove c is exemplified. 
     Each of the first blade  121  and the third blade  131  may be positioned such that the conductor-receiving groove b thereof is positioned in a conductor-receiving groove  117  disposed relatively away from the actuator  140  among a pair of conductor-receiving grooves  117  defined in each support structure. In this regard, the non-interference groove c may be defined in the blade body a of each of the first blade  121  and the third blade  131 . 
     Further, the non-interference groove c is defined in the blade such that the non-interference groove c is positioned corresponding to a conductor-receiving groove  117  located relatively close to the actuator  140  among the pair of conductor-receiving grooves  117 . For example, the non-interference groove c of the first blade  121  may be defined to coincide with the conductor-receiving groove  117  that receives the first conductor  160 . The non-interference groove c of the third blade  131  may be defined to correspond with the conductor-receiving groove  117  receiving the second conductor  165 . 
     As such, the first blade  121 , which must be connected to the first common conductor  150  disposed relatively far from the actuator  140  as compared to the first conductor  160 , may be installed at the same vertical level as the second blade  123  while avoiding interference with the first conductor  160  passing through an extension path of the first blade  121 . In the same manner, the third blade  131 , which must be connected to the second common conductor  155  disposed relatively far from the actuator  140  as compared to the second conductor  165 , may be installed at the same vertical level as the fourth blade  133  while avoiding interference with the second conductor  165  passing through an extension path of the third blade  131 . 
     In order for the actuation of the actuator  140  to achieve contact between the first blade  121  and the second blade  123  and contact between the third blade  131  and the fourth blade  133 , it is necessary for the first blade  121  and the second blade  123  to be arranged at the same vertical level and the third blade  131  and the fourth blade  133  to be arranged at the same vertical level. In this regard, in this embodiment, the non-interference groove c is defined in each of the first and second blades  121  and  131 , which are to be connected to the conductors located relatively far from the actuator  140  as compared to the conductors which are closer to the actuator  140 . In this way, the first blade  121  and the second blade  123  may be arranged at the same vertical level. Further, the third blade  131  may be positioned at the same vertical level as the fourth blade  133 . 
     Thus, each of the blades  121 ,  123 ,  131 , and  133  may be fixed to the support structure disposed on a same plane as the plane on which the actuator  140  is installed. A pair of blades that are to contact each other may be arranged at the same vertical level. In this way, the switch device  100  may be configured such that the actuator  140 , the first switch  120 , and the second switch  130  may be installed in the single inner space within the single housing  110 . 
     According to this embodiment, all of the components that constitute the switch device  100  are disposed in the single inner space of the single housing  110 . More specifically, the actuator  140  is rotatably installed in the central region of the housing  110 . The first switch  120  and the second switch  130  are disposed around the actuator  140 . With this configuration, all of the first switch  120 , the second switch  130 , and the actuator  140  are disposed within the single inner space of the housing. 
     In the switch device  100 , the first common conductor  150  and the first conductor  160  are connected to the first switch  120 , and the second common conductor  155  and the second conductor  165  are coupled to the second switch  130 . The conductors  150  and  155 ,  160  and  165  extend through the single sidewall  113  and are disposed within the single inner space. All of the conductors  150  and  155 ,  160  and  165  and the first switch  120  and the second switch  130  are disposed in the single inner space. In the single inner space, the conductors  150  and  155 ,  160  and  165  are connected to the corresponding blades  121 ,  123 ,  131  and  133 . 
     There is a difference between the vertical level of the first blade  121  and the second blade  123 , which constitute the first switch  120 , and the vertical level of the third blade  131  and the fourth blade  133 , which constitute the second switch  130 . However, the vertical level difference is negligible compared to an overall vertical dimension of the housing  110 . Thus, this difference does not act as a factor to prevent the first switch  120  and the second switch  130  from being positioned in the single inner space. 
       FIG. 8  shows an operating state of the second switch of the switch device as shown in  FIG. 4 .  FIG. 9  shows operating states of the first switch and the second switch of the switch device as shown in  FIG. 4 . 
     When the knob is rotated, the valve stem connected to the knob is rotated together with rotation of the knob to open the gas valve. Accordingly, gas supply to the burner is executed. Further, rotation of the valve stem allowing opening of the gas valve may result in rotation of the actuator  140 , as shown in  FIG. 8 . 
     When the rotation of the actuator  140  is executed to a degree such that contact between the second protrusion  145  and the second switch  130  occurs, the second protrusion  145  presses the third blade  131  toward the fourth blade  133 . As a result, the third blade  131  is bent toward the fourth blade  133 , such that the third blade  131  and the fourth blade  133  contact each other. Thereby, an electrical connection is established between the third blade  131  and the fourth blade  133 , so that the second switch  130  is closed. This results in an electrical connection between the second common conductor  155  and the second connector  165  of the second switch  130 . 
     In this embodiment, the second switch  130  is connected to a display device or display  20  via the second common conductor  155  and the second conductor  165 . The display  20  may be embodied as an indicator lamp which is turned on when the valve is opened. 
     With this configuration, when the valve stem is rotated to open the gas valve so that the supply of gas is started, the second switch  130  is closed and the display  20  is activated. This allows the user to know via the display  20  that the gas valve is open. When the display  20  is implemented as an indicator lamp, the user can easily determine, based on the indicator lamp being turned on, that the gas valve is open. 
     With the second switch  130  is closed, the rotation of the knob continues to ignite the burner. Thus, as shown in  FIG. 9 , when the rotation of the actuator  140  is made to an angle at which contact between the first protrusion  143  and the first switch  120  occurs, the first protrusion  143  presses the first blade  121  toward the second blade  123 . As a result, the first blade  121  is bent toward the second blade  123  such that contact between the first blade  121  and the second blade  123  is established. 
     This results in an electrical connection between the first blade  121  and the second blade  123 , which brings the first switch  120  to a closed state. In this way, an electrical connection between the first common conductor  150  and the first conductor  160  of the first switch  120  is established. 
     In this embodiment, the first switch  120  is exemplified as being connected to an ignition device  30  through the first common conductor  150  and the first conductor  160 . With this configuration, the knob is rotated substantially to a maximum angle for the ignition of the burner while the gas is being supplied to the burner. In response, actuation of the actuator  140 , resulting from the rotation of the valve stem connected to the knob, causes the first switch  120  to be closed. 
     In response, the ignition device  30  for igniting the gas supplied to the burner is activated. Thus, ignition of the burner may be executed. 
     While the knob is being turned, that is, while gas is being supplied to the burner, the second switch  130  may remain closed. On the other hand, the first switch  120  may be closed only during a portion of the continuous rotation period of the knob. That is, the switch device  100  may be configured such that in a state in which the knob is rotated for opening the valve, the tuned on state of the indicator lamp is continuously maintained, while the first switch  120  activated for ignition of the burner is closed only for a specific period. 
     To achieve this, in this embodiment, a circumferential extension dimension of the first protrusion  143  and a circumferential extension dimension of the second protrusion  145  may be set differently. For example, the second protrusion  145  may extend along a substantial portion of the circumferential dimension of the actuator  140 . Conversely, the first protrusion  143  may extend along only a short portion of the circumferential dimension of the actuator  140 . The first protrusion  143  may be located at a higher level than the second protrusion  145 . When viewed from the open top of the first housing  110   a  toward the bottom face  111  of the first housing  110   a , an entirety of the first protrusion  143  may overlap the second protrusion  145 . 
     Accordingly, in a state in which the knob  10  is rotated, the second switch  130  may be kept closed so that the turned-on state of the indicator lamp may be maintained continuously. The turned-on state of the indicator lamp may be maintained even when the first switch  120  is closed so that ignition of the burner is executed. 
     That is, operations of multiple functional units may be controlled using the single switch device  100 . Operations of the multiple functional units controlled via the single switch device  100  may be performed simultaneously. Alternatively, the operations of the functional units may be performed at different timings. 
     Further, in this embodiment, the switch device  100  has the two switches  120  and  130 . Thus, the switch device  100  is configured to control operations of two functional units. However, embodiments are not limited to this configuration. According to embodiments, the switch device  100  may have three or more switches. Thus, the single switch device may be configured to control operations of three or more functional units. That is, various modifications may be contemplated. 
     The switch device  100  according to this embodiment may be provided for a multi-switching function in which multiple circuits are switched by rotation of a single rotational shaft, that is, the single knob and the valve stem connected thereto. That is, embodiments may effectively provide for the multi-switching function using only one switch device instead of a plurality of switch devices. 
     Further, in the switch device  100  according to this embodiment, the plurality of switches  120  and  130  may be disposed in the single inner space defined in the single housing  110 . Thus, a vertical stack of the switches  120  and  130  in order to realize the multi-switching function may not be required. 
     When the switches  120  and  130  are stacked in the vertical direction, respective structures for supporting the stacked switches  120  and  130  respectively need to be added. Therefore, a number of partitioning structures for dividing the internal space of the housing  110  in the vertical direction, corresponding to the number of the switches  120  and  130  should be added in the housing  110 . 
     When the partitioning structures for partitioning the inner space of the housing  110  are added to the housing  110 , the internal structure of the switch device  100  becomes complicated correspondingly. Further, a volume of the switch device  100  must be increased by a thickness occupied by the partitioning structures and a dimension of the vertical stack of the switches  120  and  130 . 
     However, in the switch device  100  according to this embodiment, the plurality of switches  120  and  130  may be disposed within the single inner space of the single housing. Therefore, the switches  120  and  130  need not be stacked in the vertical direction in order to implement the multi-switching function. Accordingly, there is no need for the partitioning structures that divide the inner space of the housing  110  in the vertical direction, which may lead to a simple structure of the device. 
     That is, the switch device  100  according to this embodiment may be designed to have a simple structure without the partitioning structures for dividing the inner space of the housing  110  in the vertical direction. As a result, the switch device  100  according to this embodiment may have a compact structure, and may provide for a low manufacturing cost. 
     The switch device  100  of this embodiment may be manufactured at a low manufacturing cost while having a compact structure, and at the same time, may effectively provide for the multi-switching function. As a result, an increase in the manufacturing cost of the cooking appliance including the switch device  100  is suppressed. Further, an increase in volume occupied by the switch device  100  in the cooking appliance is suppressed. This may suppress an increase in the manufacturing cost of the cooking appliance due to the addition of the switch device. Control of operations of various functional units for convenient use of the cooking appliance may be executed effectively with the single switch device. 
     A switch device having such a configuration is merely one embodiment. Thus, various modifications may be made to the embodiment discussed above without departing from the scope. 
       FIG. 10  is a perspective view showing an internal structure of a switch device according to another embodiment.  FIG. 11  shows an operating state of a second switch of the switch device as shown in  FIG. 10 .  FIG. 12  shows operating states of a first switch and a second switch of the switch device as shown in  FIG. 10 .  FIG. 13  is a perspective view showing an internal structure of a switch device according to an embodiment.  FIG. 14  shows an operating state of a second switch of the switch device as shown in  FIG. 13 .  FIG. 15  shows operating states of a first switch and a second switch of the switch device as shown in  FIG. 13 .  FIG. 16  is a perspective view showing an internal structure of a switch device according to embodiment.  FIG. 17  is a cross-sectional view, taken along line XVII-XVII of  FIG. 16 . 
     Hereinafter, various embodiments will be described with reference to  FIG. 10  to  FIG. 17 . With this configuration, the same reference numerals used in the drawings described above with reference to the previous embodiment may refer to the same components having the same functions in the following embodiments. Therefore, redundant description of the same components has been omitted. 
     Referring to  FIGS. 10 to 12 , according to this embodiment, switch device  200  has a configuration in that the switch device  200  is connected to three conductors rather than four conductors. That is, the switch device  200  of this embodiment is connected to three conductors. Thus, in this configuration, the number of the conductors is reduced by one compared to that illustrated in the previous embodiment. 
     According to this embodiment, the actuator  140  is installed in the central region of the bottom face  111  having the central hole  112  defined therein. Further, around the central region of the bottom face  111  where the actuator  140  is installed, a single conductor  160  is disposed at one or a first side in the first direction Y, while a pair of conductors  150  and  165  is placed at the other or a second side in the first direction Y. 
     In this embodiment, around the central region of the bottom face  111  where the actuator  140  is installed, the first conductor  160  is disposed at the first side in the first direction Y, while the common conductor  150  and the second conductor  165  are disposed at the second side in the first direction Y. Thus, the number of the common conductor coupled to the switch device  200  in this embodiment is one. That is, the switch device  200  is connected to the single common conductor  150 . 
     As with the first switch  120  (see  FIG. 5 ) and the second switch  130  (see  FIG. 5 ) illustrated in the previous embodiment, first switch  220  may include the first blade  121  and the second blade  123 , and second switch  230  may include the third blade  131  and the fourth blade  133 . 
     The first switch  220  and the second switch  230  illustrated in this embodiment differ from the first switch  120  and the second switch  130  illustrated in the previous embodiment as follows: the first blade  121  constituting the first switch  220  and the third blade  131  constituting the second switch  230  are integrally formed in this embodiment. That is, in the switch device  200  of this embodiment, the first blade  121  and the third blade  131  which are connected to the common conductor  150  are integrally formed to define an integration of the first blade  121  and the third blade  131 . The integration of the first blade  121  and the third blade  131  may be installed to be connected to the single common conductor  150  inside the housing  110 . 
     In one example, when viewed from the open top of the first housing  110   a  toward the bottom face  111  of the first housing  110   a , the integration of the first blade  121  and the third blade  131  may be configured to have an inverted-L shape. With this configuration, the first blade  121  may extend in a direction parallel to the second direction X, while the third blade  131  may extend in a direction parallel to the first direction Y. 
     In the integration of the first blade  121  and the third blade  131 , the conductor-receiving portion b may be included only in one of the first blade  121  or the third blade  131 . That is, when only one of the first blade  121  or the third blade  131  may be connected to the common conductor  150 , both the first blade  121  and the third blade  131  may be electrically connected to the common conductor  150 . 
     For example, when electrical connection is established between the common conductor  150  and the third blade  131  through coupling between the conductor-receiving portion b included in the third blade  131  and the common conductor  150 , the first blade  121  may be electrically and indirectly coupled to the common conductor  150  via the third blade  131  without being directly coupled to the common conductor  150 . In addition, in this embodiment, an example in which the first blade  121  is positioned closer to the actuator  140  than the second blade  123 , and the third blade  131  is disposed at a position relatively farther from the actuator  140  than the fourth blade  133  is exemplified. 
     In this manner, generally, at least one of the first blade  121  or the third blade  131  integrally connected is positioned so as not to be in direct contact with the actuator  140 . For example, the first blade  121 , which is positioned relatively closer to the actuator  140  than the second blade  123 , is positioned to be in direct contact with the first protrusion  143  when the contact between the first protrusion  143  and the first switch  220  is made. However, the third blade  131 , which is located relatively farther away from the actuator  140  than the fourth blade  133 , is positioned so as not to be in direct contact with the second protrusion  145  when the contact between the second protrusion  145  and the second switch  230  is made. 
     If both the first blade  121  and the third blade  131  are positioned to be in direct contact with the actuator  140 , concurrent operations of the first switch  220  and the second switch  230  is not properly achieved. For example, when both the first blade  121  and the third blade  131  are positioned to be in direct contact with the actuator  140 , the switch device  200  may operate as follows: when contact is established between the third blade  131  and the actuator  140 , the third blade  131  is pressed by the second protrusion  145 . In response, a shape of the third blade  131  is deformed such that the third blade  131  is pushed toward the fourth blade  133 . 
     When the shape of the third blade  131  is deformed, a position of the first blade  121  connected to the third blade  131  is changed. Thus, the first protrusion  143  fails to press the first blade  121  properly. Alternatively, even when the first protrusion  143  presses the first blade  121 , contact between the first blade  121  and the second blade  123  is not properly achieved. Thus, the first switch  220  may not be closed properly. 
     In view of this, in this embodiment, at least one of the first blade  121  or the third blade  131  integrally connected is disposed in a position not in direct contact with the actuator  140 . This may allow the concurrent operations of the first switch  220  and the second switch  230  to be enabled properly without being affected by a state in which the two blades  121  and  131  are connected integrally. 
     All the components constituting the switch device  200  as described above may be disposed in a single inner space within the single housing  110 . More specifically, the actuator  140  may be rotatably installed in a central region of the housing  110 . The first switch  220  and the second switch  230  may be disposed around the actuator  140 . With this configuration, the first switch  220 , the second switch  230 , and the actuator  140  are all located in the single inner space. 
     In the switch device  200 , the first conductor  160  may be connected to the first switch  220 , the second conductor  165  may be connected to the second switch  230 , and the common conductor  150  may be connected to both the first switch  220  and the second switch  230 . The conductors  150 ,  160 , and  165  may extend through the single sidewall  113  and be disposed within the single inner space. All of the conductors  150 ,  160 , and  165  and the first switch  220  and the second switch  230  may be disposed in the single inner space. In the single inner space, the conductors  150 ,  160 , and  165  may be connected to the corresponding blades  121 ,  123 ,  131 , and  133 . 
     The switch device  200  according to this embodiment may provide for a multi-switching function in which multiple circuits are switched by rotation of the single rotational shaft, that is, the single knob and the valve stem connected thereto. That is, this embodiment may effectively provide for the multi-switching function using only one switch device instead of a plurality of switch devices. 
     Further, in the switch device  200  according to this embodiment, the plurality of switches  220  and  230  may be disposed in the single inner space defined in the single housing  110 . Thus, a vertical stack of the switches  220  and  230  in order to realize the multi-switching function may not be required. 
     When the switches  220  and  230  are stacked in the vertical direction, respective structures for supporting the stacked switches  220  and  230  respectively need to be added. Therefore, a number of partitioning structures for dividing the internal space of the housing  110  in the vertical direction, corresponding to the number of the switches  220  and  230  should be added in the housing  110 . 
     When the partitioning structures for partitioning the inner space of the housing  110  are added to the housing  110 , an internal structure of the switch device  200  becomes complicated correspondingly. Further, a volume of the switch device  200  must be increased by a thickness occupied by the partitioning structures and a dimension of the vertical stack of the switches  220  and  230 . 
     However, in the switch device  200  according to this embodiment, the plurality of switches  220  and  230  may be disposed within the single inner space of the single housing  110 . Therefore, the switches  220  and  230  need not be stacked in the vertical direction in order to implement the multi-switching function. Accordingly, there is no need for the partitioning structures that divide the inner space of the housing  110  in the vertical direction, which may lead to a simple structure of the device. 
     That is, the switch device  200  according to this embodiment may be designed to have a simple structure without the partitioning structures for dividing the inner space of the housing  110  in the vertical direction. As a result, the switch device  200  according to this embodiment may have a compact structure, and may provide for a low manufacturing cost. 
     Further, in the switch device  200  of this embodiment, the plurality of switches  220  and  230  may be disposed in the single inner space within the single housing  110 . With this configuration, only the single common conductor  150  may be used to implement the multiple switches  220  and  230 . If the switches  220  and  230  are stacked in the vertical direction to implement the multi-switching function, a pair of conductors connected to each of the switches  220  and  230  which are positioned in the layers respectively is required. Thus, even though both one of a first pair of the conductors coupled to the first switch  220  in the first layer and one of a second pair of the conductors coupled to the second switch  220  in the second layer act as common conductors connected to the same potential, the first pair of conductors is required in the first layer and the second pair of conductors is required in the second layer. 
     However, in the switch device  200  of this embodiment, a plurality of switches  220  and  230  disposed in the single inner space of the single housing  110  may share the single common conductor  150 . Thus, the single common conductor  150  alone may implement all of the plurality of switches  220 ,  230 . 
     With this configuration, the switch device  200  of this embodiment may reduce the number of conductors required to realize the switch device  200 . This allows the switch device  200  to be manufactured at a low manufacturing cost while having a more compact structure. Further, there is an advantage that wirings in the cooking appliance in which the switch device  200  is installed may be more simply configured. 
     Referring to  FIGS. 13 to 15 , according to this embodiment, switch device  300  may be connected to three conductors like the switch device  200  (see  FIG. 10 ) as illustrated in the previous embodiment. In this embodiment, around the central region of the bottom face  111  where the actuator  140  is installed, common conductor  150  may be disposed at one or a first side in the first direction Y, while at the other or a second side in the first direction Y, the first conductor  160  and the second conductor  165  may be disposed. 
     Further, the first switch  320  may include a first blade  121  and a second blade  123 . The second switch  330  may include a third blade  131  and a fourth blade  133 . 
     With this configuration, the first blade  121  and the third blade  131  connected to the conductor  150  may be integrally connected to form an integration of the first blade  121  and the third blade  131 . When viewed from the open top of the first housing  110   a  toward the bottom face  111  of the first housing  110   a , the integration of the first blade  121  and the third blade  131  has a clockwise 90 degree rotated T shape. 
     The second blade  123  may be connected to the first conductor  160 . The fourth blade  133  may be connected to the second conductor  165 . With this configuration, the first blade  121  and the second blade  123  may face each other in the first direction Y, while the third blade  131  and the fourth blade  133  may face each other in the second direction X. 
     The third blade  131  and the first blade  121  may be arranged at different positions from the bottom surface  111  of the first housing  110   a , that is, at different vertical levels. In one example, the third blade  131  is disposed at a higher level than the first blade  121 . 
     Further, the first blade  121  may be positioned at a vertical level corresponding to the vertical level of the second blade  123 , while the third blade  131  may be disposed at a vertical level corresponding to the vertical level of the fourth blade  133 . The integration of the first blade  121  and the third blade  131  has a single conductor-receiving portion b coupled to the common conductor  150 . A blade body a of the integration of the first blade  121  and the third blade  131  is branched into two branches. 
     With this configuration, the blade body a may branch in two mutually perpendicular directions to define the first blade  121  and the third blade  131 , respectively. For example, a first branch extending in a direction parallel to the first direction Y may define the third blade  131 , while a second branch extending in a direction parallel to the second direction X may define the first blade  121 . The first and second branches may be formed at different vertical levels. 
     That is, the blade body a may be cut to be divided into an upper level portion and a lower level portion, and then, the upper level portion and the lower level portion may be bent at right angles relative to each other. This allows the integration of the first blade  121  and the third blade  131  to be formed such that contact between the first blade  121  and the second blade  123  and contact between the third blade  131  and the fourth blade  133  may occur at different vertical levels. 
     The second blade  123  may be formed as an inversed-L shape. The second blade  123  may be connected to the first conductor  160  at the second side in the first direction Y. The second blade  123  may be configured to be contactable with the first blade  121  disposed at the first side in the first direction Y. This may be realized via the inversed-L shape thereof. 
     Further, the fourth blade  133  may be connected to the second conductor  165  at the second side of the first direction Y. The fourth blade  133  may be configured to be contactable with the third blade  131  disposed at the first side in the first direction Y. That is, the fourth blade  133  may have a straight shape extending in the first direction Y. 
     Referring to the arrangement of the blades  121 ,  123 ,  131 , and  133  that constitute the first switch  320  and the second switch  330 , the integration of the first blade  121  and the third blade  131  may be located relatively farther from the actuator  140  than the second blade  123  and the fourth blade  133 , which are separately formed. That is, the integration of the first blade  121  and the third blade  131  may be positioned as follows: when contact between the first protrusion  143  and the first switch  320  is made, the integration of the first blade  121  and the third blade  131  is not in direct contact with the first protrusion  143 ; and when contact between the second protrusion  145  and the second switch  330  is made, the integration of the first blade  121  and the third blade  131  is not in direct contact with the second protrusion  145 . 
     In this way, pressurization from the actuator  140  is not applied directly to the integration of the first blade  121  and the third blade  131  in order that the first switch  320  is closed and the second switch  330  is closed. Thus, concurrent operations of the first switch  320  and the second switch  330  may be effected without being affected by the state that the two blades  121  and  131  are formed as a single body. 
     As shown in  FIG. 16  and  FIG. 17 , a switch device  400 , according to another embodiment, may be connected to three conductors as in the switch device  300  (see  FIG. 15 ) illustrated in the previous embodiment. According to this embodiment, the actuator  140  may be installed in the central region of the bottom face  111  where the central hole  112  is defined. Further, around the central region of the bottom face  111  where the actuator  140  is installed, first conductor  160  and second conductor  165  may be disposed at one or a first side in the first direction Y, while a single common conductor  150  may be disposed at the other or a second side in the first direction Y. 
     With this configuration, the first conductor  160  may be disposed a relatively farther distance from the actuator  140  and the common conductor  150  than the second conductor  165 . The common conductor  150 , the first conductor  160 , and the second conductor  165  may be disposed at a same distance from the bottom face  111  of the first housing  110   a . That is, the common conductor  150 , the first conductor  160 , and the second conductor  165  may be arranged at a same vertical level. 
     The configuration in which the conductors  150 , and  160  and  165  are arranged at the same vertical level may reduce the vertical dimension of the housing  110  as required for the installation of the conductors as compared with the configuration where the conductors are arranged at different vertical levels. This may allow a more compact switch device  400  to be realized. 
     In order for all the conductors  150 , and  160  and  165  to be placed at the same vertical level, it is required to modify an arrangement structure of blades  421 ,  423 ,  431 , and  433  connected to the above-described conductors. Hereinafter, the arrangement structure of the blades  421 ,  423 ,  431 , and  433  will be described. 
     According to this embodiment, the switch device  400  may include first switch  420  and second switch  430 . The first switch  420  may include first blade  421  and second blade  423 . The second switch  430  may include third blade  431  and fourth blade  433 . 
     The first blade  421  may be connected to the common conductor  150  disposed at the second side of the first direction Y of the housing  110 . The first blade  421  may have a straight shape extending along the first direction Y. 
     The second blade  423  may be connected to the first conductor  160  disposed at the first side in the first direction Y of the housing  110 . The second blade  423  may have a straight shape extending along the first direction Y. 
     The third blade  431  may be connected to the common conductor  150  together with the first blade  421 . The third blade  431  may have a straight shape extending along the first direction Y. 
     According to this embodiment, the first blade  421 , which is a component of the first switch  420 , and the third blade  431 , which is a component of the second switch  430  may be integrally connected to form the integration of the first blade  421  and the third blade  431 . That is, in the switch device  400  in this embodiment, the first blade  421  and the third blade  431 , which are components connected to the common conductor  150  may be integrally connected. The integration of the first blade  421  and the third blade  431  may be installed to be connected to the single common conductor  150  inside the housing  110 . 
     The integration of the first blade  431  and the third blade  433  may be connected to the common conductor  150  disposed at the second side in the first direction Y of the housing  110 . The integration of the first blade  431  and the third blade  433  may have a linear shape extending along the first direction Y. The integration of the first blade  431  and the third blade  433  may have a length configured to allow contact thereof with both the second blade  423  and the fourth blade  433 . The integration of the first blade  431  and the third blade  433  may have a construction to allow contact thereof with both the second blade  423  and the fourth blade  433 , which are located at different vertical levels. 
     In one example, from a side elevation view of the housing  110 , the integration of the first blade  421  and the third blade  431  has a “ ” shape. Both the first blade  421  and the third blade  431  extend in a direction parallel to the first direction Y. The integration of the first blade  421  and the third blade  431  may be constructed such that the first blade  421  is disposed a greater distance from the bottom face  111  of the first housing  110   a  than the third blade  431 , that is, the first blade  421  may be positioned at a higher level than the third blade  431 . 
     In the integration of the first blade  421  and third blade  431 , only one of the first blade  421  or the third blade  431  may have a conductor-receiving portion b. That is, when only one of the first blade  421  or the third blade  431  is connected to the common conductor  150 , both the first blade  421  and the third blade  431  may be electrically connected to the common conductor  150 . 
     For example, when an electrical connection is established between the common conductor  150  and the third blade  431  via the coupling between the conductor-receiving portion b included in the third blade  431  and the common conductor  150 , the first blade  421  may be electrically coupled to the common conductor  150  via the third blade  431  without being directly coupled to the common conductor  150 . That is, the integration of the first blade  421  and the third blade  431  shares the single conductor-receiving portion b. The electrical connection between the two blades  421  and  431  and the common conductor  150  may be completed at once by merely connecting the single conductor-receiving portion b to the common conductor  150 . 
     The fourth blade  433  may be connected to the second conductor  165  disposed at the first side in the first direction Y of the housing  110 . The fourth blade  433  may have a straight shape extending along the first direction Y. 
     In this embodiment, the first conductor  160  may be disposed at a position relatively far from the actuator  140  than the second conductor  165 . Therefore, the second blade  431  may have a greater horizontal length than the fourth blade  421 . 
     The main difference between the second blade  423  and the fourth blade  433  is that while the fourth blade  433  has a generally linear shape, the second blade  423  has a generally inversed-L shape, when viewed toward a side face of the housing  110 . According to this embodiment, as the first conductor  160  is disposed at a position relatively farther from the actuator  140  than the second conductor  165 , the second blade  423  to be connected to the first conductor  160  needs to have an interference-avoiding structure to avoid interference with the second conductor  165  passing through the extension path of the second blade to the first conductor  160 . 
     With this in mind, the second blade  423  of this embodiment has the following construction. The receiving portion b of the second blade  423 , coupled with the support structure of the first conductor  160  and the housing  110  may be formed at a vertical level higher than the vertical level of the second conductor  165 . Further, the blade body a extending from the conductor-receiving portion b may be spaced from the bottom face  111  of the first housing  110   a  and may be formed at a level higher than the vertical level of the second conductor  165 . That is, the blade body a extending from the conductor-receiving portion b may extend at a level higher than the second conductor  165 . 
     That is, the conductor-receiving portion b and the blade body a of the second blade  423  together may define the inversed-L shape when viewed from the side face of the housing  110 . The second conductor  165  may pass through below the blade body a of the second blade  423 . Thus, all of the blades  421 ,  431 ,  431 , and  433  may be space-efficiently positioned within the single inner space within the housing  110  to realize the switch device  400 . 
     Referring to the array structure of the blades  421 ,  423 ,  431 , and  433  constituting the first switch  420  and the second switch  430 , the integration of the first blade  421  and third blade  433  is positioned at a farthest position from the actuator  140 , while the second blade  423  and the fourth blade  433  are positioned between the integration of the first blade  421  and the third blade  433  and the actuator  140 . The blades  421 ,  423 ,  431  and  433  positioned in this manner are arranged at a predetermined spacing from each other in the second direction X. 
     In this embodiment, all of the first blade  421 , the second blade  421 , the third blade  431 , and the fourth blade  433  may be positioned in one of two sub-regions partitioned in the second direction X about the actuator  140 . For example, the integration of the first blade  421  and the third blade  431  may be positioned adjacent to one of two parallel longitudinal side walls constituting the sidewall  113 , where the one is disposed at the second side in the second direction X of the housing. Further, the second blade  423  and the fourth blade  433  may be positioned adjacent to the one of two parallel longitudinal side walls. The integration of the first blade  421  and the third blade  431  may be located at the first side in the Y direction about the actuator  140 , while the second blade  423  and the fourth blade  433  may be located at the second side in the Y direction about the actuator  140 . A virtual extension of the second blade  423  and the fourth blade  433  may be positioned between the integration of the first blade  421  and the third blade  431  and the actuator  140 . 
     Thus, when all of the blades  421 ,  423 ,  431 , and  433  are positioned in one of two sub-regions partitioned in the second direction X about the actuator  140 , a size of the housing  110  may be reduced by a size of the other of the two sub-regions partitioned in the second direction X about the actuator  140 , that is, the size of the sub-region in which the blades  421 ,  423 ,  431 , and  433  are not installed. 
     Accordingly, the switch device  400  of this embodiment may be manufactured with a more compact size due to the reduced size of the housing  110 , which may contribute to downsizing of the cooking appliance in which the switch device  400  is installed. Further, this may provide for a higher degree of design freedom for the appliance in which the switch device  400  is installed. 
       FIG. 18  is a perspective view showing an internal structure of a switch device according to another embodiment.  FIG. 19  is a cross-sectional view, taken along line XIX-XIX of  FIG. 18 . 
     Referring  FIG. 18  and  FIG. 19 , the switch device  500  according to this embodiment has a configuration similar to the switch device  400  (see  FIG. 17 ) illustrated in the previous embodiment. The first blade  421 , which is a component of first switch  520 , and the third blade  431 , which is a component of second switch  530  are integrally connected to form an integration of the first blade  421  and the third blade  431 . In this embodiment, from a side elevation view of the housing  110 , the integration of the first blade  421  and the third blade  431  has a “ ” shape. 
     In the integration of the first blade  421  and third blade  431 , only one of the first blade  421  or the third blade  431  may have a conductor-receiving portion b. That is, when only one of the first blade  421  or the third blade  431  is connected to the common conductor  150 , both the first blade  421  and the third blade  431  may be electrically connected to the common conductor  150 . 
     For example, when an electrical connection is established between the common conductor  150  and the third blade  431  via the coupling between the conductor-receiving portion b included in the third blade  431  and the common conductor  150 , the first blade  421  may be electrically coupled to the common conductor  150  via the third blade  431  without being directly coupled to the common conductor  150 . That is, the integration of the first blade  421  and the third blade  431  shares the single conductor-receiving portion b. The electrical connection between the two blades  421  and  431  and the common conductor  150  may be completed at once by merely connecting the single conductor-receiving portion b to the common conductor  150 . 
     The difference between the switch device  500  according to this embodiment and the switch device  400  illustrated in the previous embodiment is as follows: a cut-out  525  is defined within the integration of the first blade  421  constituting a portion of the first switch  520  and the third blade  431  constituting a portion of the second switch  530 . According to this embodiment, at a first side in the first direction Y of the housing  110 , the second blade  423  is positioned vertically farther from the bottom face  111  of the first housing  110   a  than the fourth blade  433 . Further, at a second side in the first direction Y of the housing  110 , the first blade  421  is positioned vertically farther from the bottom face  111  of the first housing  110   a  than the third blade  431 . This ensures that contact between the first blade  421  and the second blade  423  occurs at a higher level than contact between the third blade  431  and the fourth blade  433 . In other words, contact between the third blade  431  and the fourth blade  433  may be made at a position vertically closer to the bottom face  111  of the first housing  110   a  than the contact between the first blade  421  and the second blade  423 . 
     Further, the integration of the first blade  421  and the third blade  431  may have the cut-out  525  defined therein that partially separates the first blade  421  and the third blade  431  from each other. The cut-out  525  may be defined by cutting an elongate portion or slot between the first blade  421  and the third blade  431  which are in contact with each other. Thus, the integration of the first blade  421  and the third blade  431  may have a configuration in which a portion of the first blade  421  and a portion of the third blade  431  may be bent independently of each other. 
     In this embodiment, in the integration of the first blade  421  and third blade  431 , the first blade  421  may define an upper integration, while the third blade  431  may define a lower integration. The cut-out  525  may be defined between the first blade  421  and the third blade  431 . A shape of the cut-out  525  may have one open lateral side. 
     The construction of the integration of the first blade  421  and the third blade  431  may be provided such that when contact between the first blade  421  and the second blade  423  and contact between the third blade  431  and the fourth blade  433  occur simultaneously, the contacts at both contact points may be executed in a stable manner. That is, when the integration of the first blade  421  and the third blade  431  is established to have the cut-out  525  as described above, this may have the following effect: when the first blade  421  and the second blade  423  contact each other, a force exerted by the second blade  423  toward the first blade  421  may push the first blade  421  outwardly. Only a bent deformation of the first blade  421  is generated, and a pressing force is not transmitted to the third blade  431 . 
     Conversely, when contact is made between the third blade  431  and the fourth blade  433 , the third blade  431  is pushed outwardly by a force applied by the fourth blade  433 . Only a bent deformation of the third blade  431  is generated and a pressing force is not transmitted to the first blade  421 . 
     That is, the cut-out  525  defined between the first blade  421  and the third blade  431  may allow the first blade  421  and the third blade  431  to be independently bent. As a result, concurrent operation of the first switch  520  and the second switch  530  may be effectively conducted without being affected by a state in which the two blades  421  and  431  form the integration of the first blade  421  and the third blade  431 . 
     The switch device  500  of this embodiment as described above may provide at least the following advantages. 
     First, in the switch device  500  of this embodiment, the plurality of switches  520  and  530  may be disposed in the single inner space within the single housing  110 . With this configuration, only the single common conductor  150  may be used to implement the multiple switches  520  and  530 . 
     If the switches  520  and  530  are stacked in the vertical direction to implement the multi-switching function, a pair of conductors connected to each of the switches  520  and  530  which are positioned in the layers respectively is required. Thus, even though both of one of a first pair of the conductors coupled to the first switch  520  in the first layer and one of a second pair of the conductors coupled to the second switch  520  in the second layer act as common conductors connected to the same potential, the first pair of conductors is required in the first layer and the second pair of conductors is required in the second layer. 
     However, in the switch device  500  of this embodiment, a plurality of switches  520  and  530  disposed in the single inner space of the single housing  110  may share the single common conductor  150 . Thus, the single common conductor  150  alone may implement all of the plurality of switches  520 ,  530 . 
     With this configuration, the switch device  500  of this embodiment may reduce the number of conductors required to realize the switch device  500 . For example, the number of conductors may be reduced from 4 to 3. This allows the switch device to be manufactured at a low manufacturing cost while having a more compact structure. Further, there is an advantage in that wirings in the cooking appliance in which the switch device  500  is installed may be more simply configured. 
     Second, the switch device  500  of this embodiment has a configuration in which the integration of the first blade  421  and the third blade  431  share the single conductor-receiving portion b. Thus, the electrical connection between the two blades  421  and  431  and the common conductor  150  may be completed at once by merely connecting the shared single conductor-receiving portion b to the common conductor  150 . 
     If a switch device is configured in a structure in which the switches  520  and  530  are stacked in the vertical direction to implement a multi-switching function, a pair of conductors connected to each of the switches  520  and  530  which are positioned in the layers respectively is required. Thus, this may require fixedly inserting each of the blades to be connected to these conductors into the housing  110  and connecting the blades to the conductors should be conducted individually. 
     For example, if a switch device is configured with two switches stacked in the vertical direction, a step for installing a total of four conductors, four steps for fixedly inserting the four blades into the housing  110  respectively, and four steps for connecting the four blades to four conductors respectively should be conducted individually. 
     However, in this embodiment, the plurality of switches  520 , and  530  positioned in the single inner space of the single housing  110  share the single common conductor  150 . Further, the integration of the first blade  421  and the third blade  431  shares the single conductor-receiving portion b. Thus, the required manufacturing process steps of the switch device  500  may be reduced compared to the conventional case. That is, fabrication of the switch device  500  of this embodiment may require a step for installing a total of the three conductors  150 ,  160 , and  165 , three steps for fixedly inserting the blades  421 ,  423 ,  431 , and  433  into the housing  110  respectively, and three steps for connecting the blades  421 ,  423 ,  431 , and  433  to the three conductors  150 ,  160 , and  165  respectively. 
     The above advantages may be achieved by the following characteristic configurations of the switch device  500  of this embodiment: the configuration in which the switch device  500  is connected to the three conductors  150 , and  160  and  165 , not to four conductors; the configuration in which the first blade  421  and the third blade  431  are integrally connected to form a single integration thereof; and the configuration in which the integration of the first blade  421  and the third blade  431  shares the single conductor-receiving portion b. As the number of manufacturing process steps is reduced, the process of fabricating the switch device  500  may be very effectively simplified. Further, this may lower a risk probability that the blades  421 ,  423 ,  431 , and  433  will be removed, due to the reduced number of engaged portions with the blades  421 ,  423 ,  431 , and  433 , thereby reducing the risk of product failure. 
     Further, in the switch device  500  of this embodiment, electrical connection between the two blades  421  and  431  and the common conductor  150  may be completed at once by merely connecting the shared single conductor-receiving portion b to the common conductor  150 . This may reduce the number of the coupling points between the conductors and the blades. Further, as the number of the coupling points between the conductors and the blades is reduced, the housing  110  may be reduced in size, so that the switch device  500  with a more compact structure may be provided. 
       FIG. 20  is a perspective view of a switch device according to another embodiment.  FIG. 21  is a bottom perspective view showing an internal structure of the switch device as shown in  FIG. 20 .  FIG. 22  is a bottom view showing internal structure of the switch device as shown in  FIG. 21 .  FIG. 23  is an exploded perspective view of an actuator of the switch device as shown in  FIG. 21 . 
     Referring to  FIGS. 20 to 23 , the arrangement of switches  620  and  630  and the arrangement of blades  621 ,  623 ,  631 , and  633  constituting the switches  620  and  630  in switch device  600  according to this embodiment may be substantially similar to the arrangement of the switches ( 420  and  430 ; see  FIG. 18 ) and the arrangement of the blades ( 421 ,  423 ,  431  and  433 ; see  FIG. 18 ) in the switch device  500  as illustrated in the previous embodiment. The main difference between the switch device  600  of this embodiment and the switch device  500  of the previous embodiment lies in a location of a support structure and a specific shape of each of the blade  621 ,  623 ,  631 , and  633 . 
     According to this embodiment, the housing  110  may include a combination of first housing  110   a  and second housing  110   b , which are coupled in the vertical direction. Further, the first housing  110   a  and the second housing  110   b  may each include square-shaped bottom face  111  and sidewall  113  extending vertically from an outer edge of the bottom face  111  and surrounding the bottom face  111 . 
     In one example, coupling between the first housing  110   a  and the second housing  110   b  may be accomplished by engagement between an engaging hook  618  and a stopper protrusion  619 . More specifically, when the first housing  110   a  and the second housing  110   b  are brought into contact with each other in the vertical direction, the engaging hook  618  provided on the first housing  110   a  may be engaged with the stopper protrusion  619  provided on the second housing  110   b  so that coupling between the engaging hook  618  and the stopper protrusion  619  is performed. The coupling between the engaging hook  618  and the stopper protrusion  619  may lead to the coupling between the first housing  110   a  and the second housing  110   b . That is, assembly of the housing  110  may be completed by merely engaging the first housing  110   a  and the second housing  110   b  with each other. Thus, manufacture of the switch device  600  may be made easier and quicker. 
     In one implementation of the switch device  600 , the support structure is provided on the housing  110 , more specifically, on the second housing  110   b , which is the upper housing of the housing  110 . That is, the support structure is provided on the second housing  110   b  rather than the first housing  110   a , which is a lower housing. The support structure projects from the bottom face  111  of the second housing  110   b . The support structure may have support blocks  115  and slots  116 . 
     Further, the support structure may have conductor-receiving grooves  117  defined in the support blocks  115 . The conductor-receiving grooves  117  may accommodate therein at least one of first conductor  160 , second conductor  165 , or common conductor  150  which extend through the housing  110 . 
     Hereinafter, a configuration of each of first switch  620  and second switch  630  will be described. 
     According to this embodiment, the first switch  620  may include first blade  621  and second blade  623 . The second switch  630  may include third blade  631  and fourth blade  633 . The second blade  623  and the fourth blade  633  may each have a shape similar to each of the second blade  423  (see  FIG. 18 ) and the fourth blade  433  (see  FIG. 18 ) illustrated in the previous embodiment. 
     The second blade  623  and the fourth blade  633  illustrated in this embodiment differ from the second blade  423  and the fourth blade  433  illustrated in the previous embodiment in that the second blade  623  and the fourth blade  633  each have a contact portion d. The contact portion d may define a portion of a blade body a of each of the second blade  623  and the fourth blade  633 . The contact portion d may define a contact portion of each blade body a with the first blade  621  and the third blade  631 . That is, the contact portion d may define a longitudinal distal end of each blade body a. 
     More specifically, the contact portion d may be formed by cutting a longitudinal distal end of each blade body a of the second blade  623  and the fourth blade  633  to be branched into branched portions. In this embodiment, the contact portion d may be formed by cutting the longitudinal distal end of the blade body a to be branched into two branches. In this example, the contact portion d may be defined to have a bifurcated ⊂ shape of the end of the blade body a. 
     The contact portion d may define each of a contact portion between the second blade  623  and the first blade  621  and a contact portion between the fourth blade  633  and the third blade  631 . When the second blade  623  and the fourth blade  633  each have the contact portion d, this exhibits the following effect. The second blade  623  and the fourth blade  633  are pressed by the actuator  140  so that contacts of the second blade  623  and the fourth blade  633  with the first blade  621  and the second blade  623  respectively occur. At this time, due to the contact portion d having the cut-out, the longitudinal distal end of each of the second blade  623  and fourth blade  633  may flex more flexibly while the blades  623  and  633  contact the first blade  621  and the third blade  631 , respectively. 
     In this way, when the second blade  623  and the fourth blade  633  are in contact with the first blade  621  and the third blade  631 , respectively, the longitudinal distal ends of the second blade  623  and fourth blade  633  may flex more flexibly. This may allow contact faces between the first blades  621  and the second blades  623  and contact faces between the third blades  631  and the fourth blades  633  to contact more tightly and reliably. 
     As a result, this may effectively solve the problem of poor contact, which may otherwise occur when the contact between the blades is not properly performed. This may allow implementation of the switch device  600  with further improved performance to be achieved. 
     In one implementation of the switch device, regarding the configuration of the integration of the first blade  621  and the third blade  631 , both a blade body a defining a portion of the first blade  621  and a blade body a defining a portion of a third blade  631  may be connected to a single conductor-receiving portion b. 
     With this configuration, the blade body a defining a portion of the first blade  621  is positioned vertically closer to the bottom face  111  of the second housing  110   b  than the third blade  631 . Further, the blade body a defining a portion of the third blade  631  is positioned vertically farther away from the bottom face  111  of the second housing  110   b  than the first blade  621 . 
     According to this embodiment, the second blade  623  and the fourth blade  633  are arranged at a predetermined distance along the second direction x. Further, the blade body a defining a portion of the first blade  621  and the blade body a defining a portion of the third blade  631  are spaced apart by a distance corresponding to the spacing distance between the second blade  623  and the fourth blade  633 . For the spacing between the blade body a defining a portion of the first blade  621  and the blade body a defining a portion of the third blade  631 , the integration of the first blade  621  and the third blade  631  has a bent connector  635 . 
     The bent connector  635  may be formed between the conductor-receiving portion b included in the integration of the first blade  621  and the third blade  631  and the blade body a of the third blade  631 . Thus, the bent connector  635  connects, in a bent form, the conductor-receiving portion b included in the integration of the first blade  621  and the third blade  631  and the blade body a of the third blade  631 . 
     In one example, when viewed from the open bottom of the second housing  110   b  towards the bottom face  111  of the second housing  110   b , the bent connector  635  may connect, in a stepped shape, the conductor-receiving portion b included in the integration of the first blade  621  and the third blade  631  and the blade body a of the third blade  631 . Further, regarding the integration of the first blade  621  and the third blade  631 , when viewed from the open bottom of the second housing  110   b  toward the bottom face  111  of the second housing  110   b , the conductor-receiving portion b, the blade body a of the first blade  621  and the blade body a of the third blade  631  may be connected via the bent connector d to form a connection shape  . 
     The configuration of the integration of the first blade  621  and the third blade  631  as described above has the following advantage. When the contact between the first blade  621  and the second blade  623  and the contact between the third blade  631  and the fourth blade  633  occur at different positions along the second direction X, the opening and closing of the first switch  620  may not interfere with the opening and closing of the second switch  630 . This may result in the provision of the switch device  600  with improved operational reliability. 
     Embodiments disclosed herein provide a switch device that may provide a multi-switching function while having a compact structure and being manufactured at a low manufacturing cost, and a cooking appliance including a switching device. 
     The purposes are not limited to the above-mentioned purposes. Other purposes and advantages, not mentioned above, may be understood from the above descriptions and more clearly understood from the embodiments. Further, it will be readily appreciated that objects and advantages may be realized by features and combinations thereof as disclosed in the claims. 
     Embodiments disclosed herein provide a switch device that may include a first switch including a first blade and a second blade configured to contact or non-contact each other, the first switch being configured to be opened or closed based on a contact or non-contact between the first blade and the second blade; a second switch including a third blade and a fourth blade configured to contact or non-contact each other, the second switch being configured to be opened and closed based on a contact or non-contact between the third blade and the fourth blade; a housing for accommodating the first switch and the second switch therein; and an actuator disposed in the housing and actuated to selectively open and close the first switch and the second switch. The first switch and the second switch may be fixedly supported by a support structure disposed on a same plane as a mounting plane for the actuator and positioned in a single inner space. 
     The actuator may include a first protrusion that presses the first switch in a contact region with the first switch such that the first blade and the second blade are in contact with each other; a second protrusion that presses the second switch in a contact region with the second switch such that the third blade and the fourth blade are in contact with each other; and a rotatable body rotatably mounted on a bottom face of said housing. The first protrusion and the second protrusion may each protrude horizontally outward from an outer circumferential surface of the rotatable body. 
     The first blade and the third blade may be connected to a common conductor passing through the housing. The second blade may be connected to a first conductor passing through the housing. The common conductor and the first conductor may pass through the single inner space within the housing. The fourth blade may be connected to a second conductor passing through the housing. The common conductor and the first conductor and the second conductor may pass through the single inner space in the housing. 
     The common conductor may include a first common conductor connected to the first blade and a second common conductor connected to the second blade. The first common conductor and the first conductor may be positioned at one or a first side of a first direction of the housing. The second common conductor and the second conductor may be positioned at the other or a second side of the first direction. The actuator may be positioned between one end and the other side of the first direction. The first blade and the second blade may be positioned at one or a first side of a second direction orthogonal to the first direction. The third blade and the fourth blade may be positioned at the other or a second side of the second direction. The actuator may be positioned between the one end and the other side of the second direction of the housing. 
     The first blade and the third blade may be integrally connected. The integration of the first blade and the third blade may be connected to a single common conductor. 
     The first conductor may be positioned at the one side of the first direction of the housing. The common conductor and the second conductor may be positioned at the other side of the first direction. The actuator may be positioned between the one end and the other side of the first direction. The third blade may be connected to the common conductor. The first blade may be connected to the third blade in an inverted-L shape. The first blade and the second blade may be positioned facing each other in the first direction. The third blade and the fourth blade may be positioned facing each other in the second direction. 
     The common conductor may be positioned at the one side of the first direction of the housing. The first conductor and the second conductor may be positioned at the other side of the first direction. The actuator may be positioned between the one end and the other side of the first direction. The third blade may be connected to the common conductor. The first blade may be connected to the third blade to form a clockwise 90 degrees rotated T shape. The first blade and the second blade may be positioned facing each other in the first direction. The third blade and the fourth blade may be positioned facing each other in the second direction. 
     The common conductor may be positioned at the one side of the first direction of the housing. The first conductor and the second conductor may be positioned at the other side of the first direction. The actuator may be positioned between one end and the other side of the first direction. The second conductor may be positioned a greater distance from the common conductor than the first conductor. The second blade may include a blade body having a length extending in the first direction and defining a contact face for contacting the first blade, and a conductor-receiving portion that receives the first conductor to allow coupling the blade body to the first conductor. The conductor-receiving portion and the blade body may be connected with each other to form an inverted-L shape so that the blade body may be positioned at a higher vertical level from the bottom face of the housing than that of the second conductor. 
     The second blade may be positioned at a higher vertical level from the bottom face of the housing than the fourth blade. The first blade may be positioned at a higher vertical level from the bottom face of the housing than the third blade. The integration of the first blade and the third blade may be constructed such that both a blade body defining a portion of the first blade and a blade body defining a portion of the third blade may be connected to the single conductor-receiving portion connected to the common conductor. A cut-out may be defined between the blade body defining a portion of the first blade and the blade body defining a portion of the third blade. The integration of the first blade and the third blade may be constructed such that the first blade defines an upper integration, the third blade defines a lower integration, and the cut-out is defined between the first blade and the third blade. 
     The second blade and the fourth blade may be arranged to be spaced apart by a predetermining spacing from each other in a second direction orthogonal to the first direction. The blade body defining a portion of the first blade and the blade body defining a portion of the third blade may be arranged to be spaced apart from each other by the spacing between the second blade and the fourth blade. 
     The integration of the first blade and the third blade may include a bent connector. The bent connector may separate the blade body defining a portion of the third blade from the blade body defining a portion of the first blade by a predetermined distance along the second direction. The bent connector may be connected to the conductor-receiving portion. 
     The blade body of the at least one of the second blade or the fourth blade may have a contact portion with the integration of the first blade and the third blade. The contact portion may be branched into a plurality of spaced and branched portions. The contact portion may be defined with a ⊂ shape at an end of the blade body. 
     All of the first blade, the second blade, the third blade, and the fourth blade may be positioned in one of both opposite ends of the second direction of the housing. The second direction may be orthogonal to the first direction. The actuator may be positioned between both opposite ends of the second direction of the housing. 
     The housing may include a bottom face on which the first switch, the second switch, and the actuator are installed, and a sidewall that surrounds the bottom face. The integration of the first blade and the third blade may be positioned adjacent to one of two parallel longitudinal side walls constituting the sidewall. The one may be disposed at the other side of the second direction. The second blade and the fourth blade may be positioned adjacent to one of two parallel longitudinal side walls. A virtual extension of the second blade and the fourth blade may be positioned between the integration of the first blade and the third blade and the actuator. 
     One of the first blade or the second blade, positioned closer to the actuator, may be positioned such that at least a portion thereof is present or located within a displacement range of the first protrusion. One of the third blade and the fourth blade, which is positioned closer to the actuator, may be positioned such that at least a portion thereof is present or located within a displacement range of the second protrusion. 
     One of the first blade or the second blade, positioned closer to the actuator, may be positioned farther from the bottom face of the housing than the third blade and the fourth blade. The first protrusion may be positioned farther from the bottom face of the housing than the second protrusion. 
     One of the first blade or the second blade, positioned closer to the actuator, may be positioned farther from the bottom face of the housing than the second protrusion such that the one is positioned at a position beyond a displacement range of the second protrusion. Further, one of the third blade or the fourth blade, which is positioned closer to the actuator, may be positioned closer to the bottom face of the housing than the first protrusion such that the one is positioned at a position beyond a displacement range of the first protrusion. 
     The support structure may include support blocks that project from the bottom face of the housing, and slots defined in the support blocks. At least one of the first blade to the fourth blade is inserted into at least one slot and is fixed to at least one support block. 
     The first blade and the third blade may be connected to a common conductor that passes through the housing. The second blade may be connected to a first conductor that passes through the housing. The common conductor and the first conductor may pass through the single inner space within the housing. The fourth blade may be connected to a second conductor that passes through the housing. The common conductor and the first conductor and the second conductor may pass through the single inner space in the housing. The support structure may have a conductor-receiving groove defined in the support block. At least one of the common conductor, the first conductor, or the second conductor passing through the housing may be received in the conductor-receiving groove. 
     At least one of the first to fourth blades may include a blade body. The blade body may be inserted into the slot and is fixed to the support block, and at least a portion of the blade body may be exposed out of the support block. A conductor-receiving portion may extend from the blade body. The conductor-receiving portion may receive a corresponding conductor. The corresponding conductor may pass through the conductor-receiving groove when the blade body is fixed to the support block. The corresponding conductor may be selected from the common conductor, the first conductor, and the second conductor. 
     The blade body may have a non-interference groove defined therein. The non-interference groove may receive a corresponding conductor and prevent the conductor from interfering with the blade body. The corresponding conductor may be received in the conductor-receiving groove and may be selected from the common conductor, the first conductor, and the second conductor. 
     The support structure may have a pair of the conductor-receiving grooves spaced apart by a predetermined spacing in a lengthwise direction of the blade body. One conductor-receiving groove of the pair of conductor-receiving grooves may be positioned a greater distance from the actuator than the other conductor-receiving groove thereof. The conductor-receiving portion and the non-interference groove may coincide with the one conductor-receiving groove. A further non-interference groove may be defined to coincide with the other conductor-receiving groove. 
     Embodiments disclosed herein provide a switch device that may include a first switch including a first blade and a second blade configured to contact or non-contact each other, the first switch being configured to be opened or closed based on a contact or non-contact between the first blade and the second blade; a second switch including a third blade and a fourth blade configured to contact or non-contact each other, the second switch being configured to be opened and closed based on a contact or non-contact between the third blade and the fourth blade; a housing that accommodates the first switch and the second switch therein; and an actuator disposed in the housing and actuated to selectively open and close the first switch and the second switch. Each of the first to fourth blades may be connected to at least one of a common conductor, a first conductor, or a second conductor that passes through the housing. The common conductor, the first conductor, and the second conductor may extend at a same vertical level in the housing and be connected to at least one of the first to fourth blades in a single inner space of the housing. 
     The housing may include a bottom face on which the first switch, the second switch, and the actuator may be installed, and a sidewall that surrounds the bottom face. Notches may be defined through the sidewall. The notches may define passages through which the common conductors, the first conductor, and the second conductor pass through the housing. 
     Embodiments disclosed herein provide a cooking appliance that may include a knob configured to be rotatable; a rotational shaft configured to rotate in conjunction with the rotation of the knob; and a switch device connected to the rotational shaft to allow an actuator to be actuated in conjunction with the rotation of the rotational shaft. The switch device may include the switch device according to embodiments discussed above. 
     The cooking appliance may further include a valve configured to be opened and closed based on the rotation of the rotational shaft to control gas supply to a burner; and an ignition device configured to ignite the gas supplied to the burner. The first switch may be closed when the rotational shaft is in a position to open the valve. The ignition device may be activated using power supplied thereto when the first switch is closed. 
     The cooking appliance may further include a display device or display configured for indicating whether the valve is open. The second switch may be closed when the rotational shaft is in a position to open the valve. The display device may be activated using power supplied thereto when the second switch is closed. 
     The switch device according to embodiments may provide a multi-switching function while having a compact structure and being manufactured at a low manufacturing cost. Further, a cooking appliance including the switching device may be realized. 
     Moreover, according to embodiments, an increase in manufacturing costs of the cooking appliance including the switch device may be suppressed. Further, an increase in volume occupied by the switch device in the cooking appliance may be suppressed. This may suppress an increase in the manufacturing costs of the cooking appliance due to the addition of the switch device. Control of operations of various functional units for convenient use of the cooking appliance may be executed effectively with the single switch device. 
     Moreover, according to embodiments, the switch device may reduce the number of conductors required to realize the switch device. This allows the switch device to be manufactured at a low manufacturing cost while having a more compact structure. Further, there is an advantage that wirings in the cooking appliance in which the switch device is installed may be more simply configured. 
     Moreover, according to embodiments, the switch device may have a configuration in which the switch device is connected to three conductors, and not to four conductors; a configuration in which the first blade and the third blade are integrally connected to form a single integration thereof; and a configuration in which integration of the first blade and the third blade shares the single conductor-receiving portion. Thus, as the number of manufacturing process steps is reduced, the process of fabricating the switch device may be very effectively simplified. Further, this may lower a risk probability that the blades will be removed, due to the reduced number of engaged portions with the blades, thereby reducing the risk of product failure. 
     In the above description, numerous specific details are set forth in order to provide a thorough understanding. Embodiments may be practiced without some or all of these specific details. Examples of various embodiments have been illustrated and described above. It will be understood that the description herein is not intended to limit the claims to the specific embodiments described. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the present disclosure as defined by the appended claims. 
     It will be understood that when an element or layer is referred to as being “on” another element or layer, the element or layer can be directly on another element or layer or intervening elements or layers. In contrast, when an element is referred to as being “directly on” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. 
     Spatially relative terms, such as “lower”, “upper” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “lower” relative to other elements or features would then be oriented “upper” relative the other elements or features. Thus, the exemplary term “lower” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Embodiments of the disclosure are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the disclosure. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the disclosure should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.