Abstract:
A door assembly for a microwave oven is provided. The door assembly includes a door panel at one side of the door, with a push bar and a latch each projecting toward a body portion of the microwave oven. A latch board including levers each rotatably coupled thereto contact either the latch or the push bar to operate switches which contact the levers. The door assembly provides a simple and convenient assembly structure for a door of a microwave oven.

Description:
This application claims the benefit of the Korean Application Nos. P2003-0017195 filed on Mar. 19, 2003, and P2003-0018449 filed on Mar. 25, 2003, which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to microwave ovens, and more particularly, to a door assembly for a microwave oven, having an improved structure. 
     2. Background of the Related Art 
     In general, the microwave oven (MWO) cooks food with intermolecular friction heat generated when molecular array of food is disturbed by a high frequency wave (approx. 2,450 MHz). 
       FIG. 1  illustrates a perspective view of a related art microwave oven. 
     Referring to  FIG. 1 , the related art microwave oven is provided with a body  10 , an inner case  20 , and an outfit chamber. 
     The body  10  is provided with a front case  11 , an outer case  12 , and a frame  13 . The inner case  20  is provided inside of the body  10  for holding the food therein. The front case  11  is in a front part of the microwave oven, with a door  14  at one side thereof for opening/closing a front part of the inner case  20 . The outer case  12  covers top and side surfaces of the microwave oven, with front edges thereof fastened to the front case  11 . 
     The frame  13  covers a bottom and rear surfaces of the body  10 , to protect the inner case  20  and the outfit chamber  30  from an external environment together with the outer case  12  and the front case  11 . 
     In the meantime, the outfit chamber is formed on a side of the inner case  20  for providing various electric components thereto, including a magnetron  31 , a high voltage transformer  32 , and a fan  33 . 
     The magnetron  31  provides a microwave to an inside of the inner case  20  for heating food. The high voltage transformer  32  provides a high voltage power to the magnetron  31 . The fan  33  blows air into an inside of the body  10 , for cooling various electric components. 
     In the meantime, there are brackets  15  fixed to a front surface of the frame  13 , and the door  14  rotatably fixed to the brackets  15  opens/closes a front surface of the inner case  20 . As described later, when the door  14  is closing, a latch on a door panel  141  pushes a lever on a latch board in the body  10 , to operate a switch. 
       FIG. 2  illustrates a side view of a latch board in a related art microwave oven, and  FIG. 3  illustrates a diagram showing operation of an actuator ‘A’ of a switch ‘S’ when the latch  142  of the door is inserted into a latch board  101 . The frame  13  is on a front surface of the inner case  20 , and the latch board  101  is on the frame  13 . 
     The latch board  101  has three levers L 1 , L 2 , and L 3 , and 3˜5 switches ‘S’ fitted therein. The switches ‘S’ include a first safety switch S 1 , a second safety switch S 2 , and a monitor switch S 3 . 
     Referring to  FIG. 2 , the first safety switch ‘S 1 ’ is in a lower part of the latch board  101 , the monitor switch ‘S 3 ’ is in a central part, and the second safety switch ‘S 2 ’ in an upper part. Each of the switches ‘S’ is fastened to the latch board  101  with two fastening pins ‘P’ and a hook ‘H’. 
     There are two holes in a diagonal direction of each of the switches ‘S’. After the fastening pins ‘P’ are aligned with the holes, the switches ‘S’ are pressed down, to insert the switch ‘S’ into the hook ‘H’ and fasten the switch ‘S’. 
     A related art door latch structure will be described. 
     Referring to  FIG. 2 , there are latch inlets  103  in a front part of the latch board  101  for inserting the latch  142 . An upper latch inlet  103  has a sloped surface  104  for guiding an upper latch  142   a  to upward. 
     Referring to  FIG. 3 , the upper latch  142   a  is engaged with one end of the first lever L 1  as the upper latch  142   a  moves up along the sloped surface  104  and drops at an end of the sloped surface  104 . In this instance, the upper latch  142   a  pushes the first lever L 1 . 
     In the meantime, a lower latch  142   b  is inserted into a lower latch inlet  103 . In this instance, the lower latch  142   b  pushes both one end of the second lever L 2  and one end of the third lever L 3  below the second lever L 2 . 
     In this instance, other end of the first lever L 1  pushes an actuator A 2  of the second safety switch S 2 , and the second lever L 2  and the third lever L 3  push the monitor switch S 3  and actuators A 1  and A 3  of the first safety switch S 1 , respectively. 
     According to this, the first lever L 1  operates the second safety switch S 2 , the second lever L 2  operates the monitor switch S 3 , and the third lever L 3  operates the first safety switch S 1 . 
     In the meantime, when the door is opened, a door handle is operated, to lift the latches  142   a  upward, so that the latches  142  are pulled out of the latch inlets  103 . Thereafter, as the levers L, respectively turned by the latches  142 , are restored by the springs  107  respectively, the actuators ‘A’ on the switches ‘S’ are released, respectively. 
     A related art assembly structure of the door will be described.  FIG. 4  illustrates fitting of the pin to the related art door, and  FIG. 5  illustrates fastening of the pin. 
     Referring to  FIG. 4 , there are horizontal members  50  on an upper part and a lower part of an inside of the door  14 . The horizontal member  50  is extended form an edge of the door  14 . The horizontal member  50  has a pin  55  fastened thereto for serving as a rotation shaft of the door  14 . 
     Referring to  FIG. 5 , the horizontal member  50  has a hole  51  formed therein, for inserting the pin  55  therein. The pin  55  has a flange  56  at a middle part thereof. 
     According to this, when the pin  55  is inserted into the hole  51  by a predetermined length, the flange  56  is held by a lower surface of the horizontal member  50 , when an extension  57  from a rear end of the pin  55  is projected by a length beyond the horizontal member  50 . The extension  57  is flattened by caulking. 
     Thus, as the horizontal member  50  is clamped between the flange  56  and the extension  57 , the pin  55  is fastened to one side of the horizontal member  50 . 
     In the meantime, as shown in  FIG. 1 , the brackets  15  are on one side of the frame  13 . The bracket  15  has a hole  15   a  in one end part thereof, to which the pin  55  is inserted. Thus, the door  14  is rotatably mounted on the frame  13 . The pin  55  serves as a rotation shaft of the door. 
     As described, the related art door latch board has the following problems. 
     First, the many levers and springs required as many as a number of switches increase a number of components, and results in a complicated assembly process. 
     Second, the holes, fastening pins, and hooks required for fastening the switches to the latch board requires complicated switching fastening process. 
     Third, since the pin fitted to the door is a separate component, a fitting process increases, and the extension of the pin is damaged in the caulking. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a door assembly for a microwave oven that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
     An object of the present invention is to provide a door assembly for a microwave oven that has a simple and convenient assembly structure. 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these objects and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the door assembly for a microwave oven includes a door panel at one side of the door, having a push bar and a latch both projected from one side toward a body, and a latch board including levers each fitted rotatable at contact with the latch or the push bar, and switches each operable at contact with the lever. 
     At least one of the levers has at least three arms. The levers include a first lever for being brought into contact with the push bar, and a second lever for being brought into contact with the latch. 
     The second lever includes a third arm for being brought into contact with the latch, and a second arm, and a first arm for operating the switches respectively when the third arm is pushed and rotated by the latch. The first lever includes a second arm for being brought into contact with the push bar, and a first arm for operating the switch when the second arm is pushed and rotated by the push bar. 
     The door panel is preferably formed as one unit with the door. The latch board includes a push bar hole and a latch hole for inserting the push bar and the latch, respectively. 
     The latch has a sloped surface at an end part for inserting the latch into the latch hole as the sloped surface slides the latch hole. The latch hole includes a projection on an inside edge for hooking the latch. The lever is held by an upper side of the projection. 
     The door assembly further includes a spring having one end hooked at a hook at one side of the latch, and the other end held in an upper part of the door panel. The spring provides a restoring force for rotating the latch, which pushes the arm of the lever. 
     Preferably, the switches are fitted on a front surface and a rear surface of the latch board in parallel. The latch board has a fastening pin and boss, and the switch has holes for inserting the fastening pin and the boss, for fastening the switch to the latch board with screw fastened to the boss. 
     The levers rotate to original positions when the levers are disengaged from the latch or the push bar. The latch board has stoppers for holding the levers at preset positions, respectively. 
     The levers are fitted to rotation shafts projected from the door panel respectively, and the levers fitted to the rotation shafts are held by hooks, respectively. The lever has a sloped surface at a part the lever is brought into contact with the hook in fitting the lever to the rotation shaft. 
     In other aspect of the present invention, there is provided a door assembly for a microwave oven including a door panel at one side of the door, having a push bar and a latch both projected from one side toward a body, and a latch board including levers each fitted rotatable at contact with the latch or the push bar, a board wall for dividing a front surface and a rear surface, and switches fitted on the front and rear surfaces of the board wall in parallel. 
     The board wall has pass through holes formed therein, and the levers have extensions rotatable along the pass through holes, respectively. The levers operate switches on the front surface respectively, and the extensions operate the switches on the rear surfaces respectively. 
     The switches include a first safety switch, a second safety switch, and a monitor switch, and switches are fitted parallel to, and on opposite side of the switches. 
     In another aspect of the present invention, there is provided a door assembly for a microwave oven including horizontal members each extended from an upper part, or a lower part of an edge of the door, pins each formed as one unit with one of the horizontal members, and brackets on a frame of the microwave oven, each having a hole for rotatably inserting the pin. 
     The pin is a projection from the horizontal member formed by pressing. The horizontal members are formed as one unit with the door. 
     In further aspect of the present invention, there is provided a door assembly for a microwave oven including a latch assembly including a door panel at one side of a door for the microwave oven, a push bar projected from the door panel toward a body, a latch rotatably fitted to the door panel spaced a distance away from the push bar, a spring having one end held at an upper part of the door panel, and the other end connected to the latch, and a fastening pin fastened through the door panel and the latch to serve as a rotation shaft of the latch, and a latch board including levers rotatable at contact with the latch and the push bar respectively, and switches operable at contact with the levers respectively. 
     The door assembly further includes a handle linked with the latch, and fitted rotatable around the fastening pin. The fastening pin has a head clamped between the door and the door panel. 
     The spring provides a restoring force for rotating the latch in one direction. The door assembly further includes a projection on one side part of the door panel for holding the latch such that the latch rotates no more than a desired angle. 
     It is to be understood that both the foregoing description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. 
       In the drawings; 
         FIG. 1  illustrates a perspective view of a related art microwave oven; 
         FIG. 2  illustrates a side view of a latch board in a related art microwave oven; 
         FIG. 3  illustrates a diagram showing latches inserted in a related art latch board to operate actuators of switches; 
         FIG. 4  illustrates a diagram showing a fastening structure of a pin to one side of a related art door; 
         FIG. 5  illustrates a diagram showing a related art pin fastening method; 
         FIG. 6  illustrates a diagram showing latches and a latch board in a microwave oven in accordance with a preferred embodiment of the present invention; 
         FIGS. 7 and 8  illustrate diagrams each showing operation between latches and a latch board following operation of a door handle of the present invention; 
         FIG. 9  illustrates a diagram showing a latch board in accordance with a second preferred embodiment of the present invention; 
         FIG. 10  illustrates a side view of a latch board in accordance with a second preferred embodiment of the present invention; 
         FIGS. 11 and 12  illustrate perspective views showing a first lever and a second lever to be fitted to a latch board in accordance with a second preferred embodiment of the present invention, respectively; 
         FIG. 13  illustrates a structure employed in each of embodiments for holding a lever on a latch board with a hook; 
         FIG. 14  illustrates a diagram of a pin formed at one side of a door in accordance with a preferred embodiment of the present invention; 
         FIG. 15  illustrates a section of a pin in accordance with a preferred embodiment of the present invention; 
         FIG. 16  illustrates a side view of a latch assembly in accordance with a preferred embodiment of the present invention; and 
         FIG. 17  illustrates a section of a latch assembly in accordance with a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings  FIGS. 6˜17 . In describing the embodiments, same parts will be given the same names and reference symbols, and repetitive description of which will be omitted.  FIG. 6  illustrates a diagram showing latches and a latch board in a microwave oven in accordance with a preferred embodiment of the present invention. 
     Referring to  FIG. 6 , there are a latch board  201  provided to one side of a frame (reference numeral  13  in  FIG. 1 ), and first and second levers L 1  and L 2  rotatably fitted to upper part and lower part of the latch board  201 , respectively. 
     The first lever L 1  has two arms, and the second lever L 2  has three arms. There is a door panel  241  at one side of a door, having a push bar  244  and a latch  242  fitted thereto. The door panel  241  may be fabricated as one unit with the door. 
     The latch board  201  has a bar hole  208  and a latch hole  209 . When the door is closed, the push bar  244  and the latch  242  are inserted into the bar hole  208  and the latch hole  209 , respectively. In this instance, the push bar  244  pushes an arm of the first lever L 1 , and the latch  242  pushes an arm of the second lever L 2 . 
     In the meantime, the head part  242   a  of the latch  242  has a hook  242   b , and the latch hole  209  has a projection  201   a  from an inside of an upper edge thereof. The hook  242   b  is hooked at the projection  201   a.    
       FIGS. 7 and 8  illustrate diagrams showing different states of engagement of the latch with the latch board following operation of the door handle when the door is closed. 
     Referring to  FIG. 7 , the latch  242  is fitted rotatable around a rotation shaft  305 , and the rotation shaft  305  has a rear end having a door handle  243  fixed thereto. An upper side of the latch  242  and one side of the door panel  241  are connected with a spring  306 . The door handle  243  is rotated in a clockwise direction in opening the door. 
     When the door handle  243  is rotated in the clockwise direction, the latch  242  also rotates in the clockwise direction, and disengaged from the projection  201   a . In this instance, a restoring force is provided from the spring  306  to the latch  242  for rotating the latch  242  in a counter clockwise direction. 
       FIG. 8  illustrates a diagram showing engagement of the latch with the latch board when the door is closed. 
     Referring to  FIG. 8 , when the door is closed, the latch  242  is inserted in the latch hole  209  as a sloped surface of the latch head  242   a  slides along an edge of the latch hole  209 , and rotates in the counter clockwise direction by the spring  306  until the hook  242   b  on the latch  242  is hooked at the projection again, when the door is locked. 
     The latch board  201  has three switches ‘S’ each of which is operable when an actuator thereon is pressed. The switches includes a monitor switch ‘S 3 ’, a second safety switch ‘S 2 ’, and a first safety switch ‘S 1 ’. The monitor switch ‘S 3 ’ is in an upper part of the latch board  201 , the second safety switch ‘S 2 ’ is in a lower part the latch board  201 , and the first safety switch ‘S 1 ’ is in a central part the latch board  201 . The actuator ‘A 3 ’ of the monitor switch ‘S 3 ’ is positioned adjacent to the arm of the first lever L 1 , and the actuators A 1  and A 2  of the first safety switch ‘S 1 ’ and the second safety switch S 2  are positioned adjacent to arms of the second lever L 2 , respectively. 
     The operation of the monitor switch ‘S 3 ’ with the first lever ‘L 1 ’ will be described. 
     Referring to  FIG. 8 , when the door on the microwave oven is closed, the push bar  244  inserted through the bar hole  208  pushes a lower arm L 12  of the first lever L 1  downward, when the first lever L 1  rotates in the counter clockwise direction until an upper arm L 11  thereof presses an actuator ‘A 3 ’ on a bottom of the monitor switch ‘S 3 ’. 
     In the meantime, referring to  FIG. 6 , when the door is opened, the push bar  244  moves back, to release a force pushing the lower arm L 12  of the first lever L 1 . According to this, the first lever L 1  rotates in a clockwise direction by gravity of the upper arm L 11 . After rotated at a certain angle, the upper arm L 11  is held at a stopper  210  thereunder, to hold the first lever L 1  in a substantial ‘           ’ position.
     Next, the operation of the first safety switch ‘S 1 ’ and the second switch ‘S 2 ’ with the second lever ‘L 2 ’ will be described. 
     Referring to  FIG. 6 , in opening the door, arms of the second lever L 2  move away from the actuators respectively. In this instance, the first arm L 21  positions over the actuator ‘A 1 ’ of the first safety switch ‘S 1 ’, the second arm L 22  positions over the actuator ‘A 2 ’ of the second safety switch ‘S 2 , and the third arm L 23  is held at the projection  201   a  on one side of the latch hole  209 . 
     In the meantime, referring to  FIG. 8 , in closing the door, the latch  242  is inserted through the latch hole  209 . Then, the latch  242  is hooked at the projection  201   a  by the restoring force provided from the spring  306 . 
     In this instance, the latch head  242   a  pushes the third arm L 23  to rotate in the clockwise direction. The first arm L 21  presses down the actuator ‘A 1 ’ of the first safety switch S 1 , and the second arm L 22  presses down the actuator ‘A 2 ’ of the second safety switch S 2 . 
     According to this, the latch board  201  in accordance with a first preferred embodiment of the present invention can operate three switches S 1 , S 2 , and S 3  only with two levers L 1 , and L 2 . Moreover, since the levers L 1  and L 2  are restored by own gravity, respectively, no separate spring is required. 
     Structures for fitting the monitor switch S 3 , the first safety switch ‘S 1 ’, and the second safety switch ‘S 2 ’ to the latch board  201  respectively will be described. 
     Each of the switches has two holes in a diagonal direction, and the latch board  201  has fastening pins  381  and bosses (not shown) at positions corresponding to positions of the holes. The fastening pins  381  and the bosses are inserted in the holes in the switches, respectively. By fastening screw  309  to the bosses, the switch ‘S’ is fastened to the latch board  201 . 
     The switches ‘S’ may be fastened by two in parallel, when the switches ‘S’ are fastened to the latch board  201  with screws  309  and fastening pin as long as a width of the switches overlapped in parallel. 
       FIG. 9  illustrates a side section of a latch board in accordance with a second preferred embodiment of the present invention, and  FIG. 10  illustrates a rear view of a latch board in accordance with a second preferred embodiment of the present invention. 
     Referring to  FIGS. 9 and 10 , the latch board  301  is divided into a front surface part and a rear surface part by a board wall  319 . The front surface part has a first lever L 1 , a second lever L 2 , a monitor switch S 3 , a first safety switch S 1 , and a second safety switch S 2  fitted thereto, and the rear surface part has the other monitor switch S 3 ′ and the other first safety switch S 1 ′. The other monitor switch S 3 ′ and the other first safety switch S 1 ′ may be substituted with switches having different functions, respectively. For simultaneous operation of the one pair of switches fitted in parallel in front and rear of the board wall  319 , the levers ‘L’ are passed through the board wall  319 . 
       FIGS. 11 and 12  illustrate perspective views showing a first lever L 1 ′ and a second lever ‘L 2 ’ to be fitted to a latch board in accordance with a second preferred embodiment of the present invention, respectively. 
     As shown in the drawings, the first lever L 1 ′ and the second lever L 2 ′ have extensions W 1  and W 2  passed through the board wall  319  respectively, and the latch board  301  has lever pass through holes  391 , and  392  the extensions W 1  and W 2  pass therethrough. Actuators of the switches fitted parallel to each other are pressed at the same time with the extensions W 1 , and W 2 . 
     For an example, two monitor switches S 3 , and S 3 ′, and actuators A 3 , and A 3 ′ thereof are fitted in parallel respectively, and the extension W 1  pass through the lever pass through hole  391  so that the first lever L 1 ′ presses the two actuators at the same time. When the push bar  244  presses the first lever L 1 ′, the extension W 1  from the upper arm is rotated. According to this, the actuators A 3 , and A 3 ′ of the monitor switches S 3  and S 3 ′ positioned in front and rear surfaces of the latch board  301  are pressed at the same time with the upper arm and the extension of the first lever L 1 ′. 
     Likewise, the extension W 2  from the second lever L 2 ′ also passes through the lever pass through hole  392  in the latch board  301 . When the latch  242  presses the second lever L 2 ′, the extension W 2  from the second lever L 2 ′ rotates. According to this, the actuators A 1 , and A 2  of the first safety switches S 1 , and S 1 ′ positioned on the front and rear surfaces of the latch board  301  are pressed at the same time by the arm and the extension W 2  of the second lever L 2 ′. 
       FIG. 13  illustrates a structure employed in each of embodiments for holding a lever L 1 , L 1 ′, L 2 , or L 2 ′ on a board wall of a latch board. 
     Referring to  FIG. 13 , the lever L is rotatably fitted to a rotation shaft  201   c  of a latch board  201 . The lever L is held with a hook  201   d  after the lever L is inserted in the rotation shaft  201   c  for preventing break away of the lever L from the rotation shaft  201   c.    
     When the lever L is inserted onto the rotation shaft  201   c , the hook  201   d  deforms elastically, and after insertion of the lever L is finished, the hook  201   d  is restored, to hold an upper part of the lever L. For preventing deformation or breakage of the hook  201   d  in contact with the lever L, a sloped surface  255  is formed at the lever L in contact with the hook  201   d . That is, since a head of the hook  201   d  slides along the sloped surface  255  when the hook  201   d  fastens the lever L, the lever L can be fitted to the latch board more stably without any damage to the lever L or the hook  201   d.    
     Moreover, it is preferable that the rotation shaft  201   c  and the hook  201   d  are formed as one unit with the latch board  201  for simplifying an assembly structure of the latch board  201 . 
     In the meantime, a mounting structure of the door on the microwave oven of the present invention will be described.  FIG. 14  illustrates a diagram of a pin formed at one side of a door as one unit with the door in accordance with a preferred embodiment of the present invention, and  FIG. 15  illustrates a section of the pin. 
     Referring to  FIG. 14 , there is a horizontal member  250  on an inside surface of the door  114 . The horizontal member  250  has a pin  250   a  formed as one unit with the horizontal member  250  for serving as a rotation shaft of the door  114 . Also, it is preferable that the horizontal member  250  is formed as one unit with the door  114 . 
     Referring to  FIG. 15 , the pin  250   a  is formed as one unit with the horizontal member  250  at one side part of the horizontal member by pressing. Therefore, it is preferable that the horizontal member  250  of the door is formed of a metal for easy pressing. Since the pin  250   a  is formed as one unit with the horizontal member  250 , fitting of the pin  250   a  is easy and damage to the pin  250   a  is prevented in comparison to a case the pin is fitted as a separate component. 
     In this instance, as the pin  250   a  is inserted to the hole  15   a  at an end part of the bracket  15 , the door  114  is rotatably mounted on the frame  13 . 
     A fitting structure of the latch of the present invention will be described.  FIG. 16  illustrates a side view of a latch assembly in accordance with a preferred embodiment of the present invention, and  FIG. 17  illustrates a section of the fitting structure. 
     Referring to  FIG. 16 , the latch assembly includes a door panel  241 , a push bar  244 , a latch  242 , a handle  243 , a spring  306 , and a fastening pin  218 . The door panel  241  is provided to one side of the door. The push bar  244  is in an upper part of the door panel  241 , and the latch  242  is in a lower part of the door panel  241 . The handle  243  has one end connected to the latch  242 . 
     The spring  306  has one end connected to an upper part of the door panel  241 , and the other end connected to a hook  242   a  on the latch  242 , so that the spring  306  provides a restoring force for rotating the latch  242  in a counter clockwise direction. 
     The latch  242  has an extension  242   c  in a lower part, and the door panel  241  has a projection  241   a  formed thereon. Since the extension  242   c  is held by the projection  241   a  at a desired angle, any further rotation of the latch  242  is prevented. 
     In the meantime, the fastening pin  218  is fastened to the door panel, passing through the door handle  243  and the latch  242 . According to this, the door handle  243  and the latch  242  turn around the fastening pin  218 . 
     The latch  242  and a link part  203  of the handle  243  are on the same rotation shaft, so that the handle  243  and the latch  242  rotate together. 
     Referring to  FIG. 16 , when the handle  243  is rotated in a clockwise direction for opening the door, the latch  242  also rotates in a clockwise direction. In this instance, the hook  242   b  at the end of the latch  242  is disengaged from the projection (reference numeral  201   a  in  FIG. 7 ). 
     Opposite to this, what is required for closing the door is just pushing the door forward in a state the handle  243  is at a regular position. In this instance, the latch  242  is inserted into the door panel  241 , and engaged with the projection  241   a.    
     Referring to  FIG. 17 , the fastening pin  218  is fitted such that a head  218   a  thereof is clamped between the door panel  241  and the door  114 , and the other end directed to an open surface of the door panel  241 . The door panel  241  is fastened to one side of the door  114  rigidly with screws or the like. 
     Thus, since the head  218   a  of the fastening pin is clamped between the door panel  241  and the door  114 , break away of the fastening pin  218  is prevented. 
     As has been described, the microwave oven of the present invention has the following advantages. 
     First, the restoration of the levers fitted to the door for the microwave oven of the present invention by gravity permits to dispense with springs, to reduce a number of required components. 
     Second, the fastening of the switches to the latch board only with screws simply without the hook permits to simplify the switch fastening structure. 
     Third, the formation of at least three arms on the lever such that one lever can operate at least two switches permits to simplify a lever fitting structure. 
     Fourth, the formation of the pin, serving as a rotation shaft of the door, as one unit with the door permits to simplify an assembly process. Moreover, breakage of the pin taken place when the pin is formed separately can be prevented. 
     Fifth, the employment of the fastening pin instead of bolt-nut as an operational rotation shaft of the latch and the door handle permits to simplify assembly, and prevents break away of the operational rotation shaft. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.