Abstract:
A heating cooker comprising a body casing, a door openably fitted to the front panel of the body casing through hinges, and an annular packing ( 40 ) of the circumferentially same shape in cross section disposed between the door and the front panel. The hinge side of the annular packing ( 40 ) fitted to the door (including a door frame ( 41 ) and a door cover ( 42 )) is positioned on the front side by a dimension L from the anti-hinge side of the annular packing.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a heating cooker. 
         [0002]    BACKGROUND ART 
         [0003]    Conventionally, there has been a heating cooker which has a main body casing and a door pivotably mounted to the main body casing and in which an annular packing seal for sealing between the main body casing and the door is attached to the rear surface side of the door (refer to, for example, JP 2000-46192 A). 
         [0004]    In the above heating cooker, the packing seal comes in contact with a front panel of the main body casing from the hinge side of the packing seal when the door is being closed, and a load due to the elastic deformation of the packing seal is applied first to the hinge side of the door in comparison with the side of the packing seal opposite to the hinge. Accordingly, there is a problem that the load due to the elastic deformation of the packing seal on the door becomes nonuniform in a state in which the door is closed, and a gap, which is located between the front panel of the main body casing and the door, becomes wider on the side opposite to the hinge, resulting in an uniform gap between the front panel of the main body casing and the door and causing an unstable sealing state. Therefore, it is concerned that the door freely opens when the internal pressure of the cooker rises, and it is necessary to securely lock the closed door by means of a mechanism such as a latch lock. 
         [0005]    It is an object of the present invention to provide a heating cooker capable of keeping a reliable sealing state by uniforming a gap between the front panel of the main body casing and the door in a state in which the door is closed without employing a mechanism such as a latch lock for locking the closed door. 
       DISCLOSURE OF THE INVENTION 
       [0006]    In order to achieve the above object, there is provided a heating cooker comprising: 
         [0007]    a main body casing having a front panel; 
         [0008]    a door connected to one side of the front panel of the main body casing via a hinge so as to open and close; and 
         [0009]    an annular packing seal provided at the door or the front panel so as to be located between the door and the front panel, wherein 
         [0010]    a portion on the hinge side of the annular packing seal is positioned closer to a front surface side than a portion opposite to the hinge side of the annular packing seal when the annular packing seal is provided at the door, or 
         [0011]    the portion on the hinge side of the annular packing seal is positioned closer to a back surface side than the portion opposite to the hinge side of the annular packing seal when the annular packing seal is provided at the front panel. 
         [0012]    According to the above construction, by providing the annular packing seal at the door and positioning the portion on the hinge side of the annular packing seal closer to the front surface side than the portion opposite to the hinge side of the annular packing seal, even if the hinge side of the annular packing seal first comes closer to the front panel of the main body casing when the door is being closed, the whole annular packing seal concurrently comes in contact with the front panel of the main body casing immediately before the door is closed, and the whole annular packing seal is elastically deformed roughly similarly in the state in which the door is closed. Otherwise, by providing the annular packing seal at the front panel of the main body casing and positioning the portion on the hinge side of the annular packing seal closer to the back surface side than the portion opposite to the hinge side of the annular packing seal, even if the hinge side of the annular packing seal first comes closer to the front panel of the main body casing when the door is being closed, the whole annular packing seal concurrently comes in contact with the front panel of the main body casing immediately before the door is closed, and the whole annular packing seal is elastically deformed roughly similarly in the state in which the door is closed. With this arrangement, a load due to the elastic deformation of the packing seal is uniformly applied to the whole door. Therefore, the gap between the front panel of the main body casing and the door is uniformed in the state in which the door is closed without employing a mechanism such as a latch lock for locking the closed door, and a reliable sealing state can be maintained. 
         [0013]    In one embodiment of the invention, the annular packing seal has a roughly identical cross section shape. 
         [0014]    In one embodiment of the invention, when the door is closed, a squeeze dimension of the portion on the hinge side of the annular packing seal is smaller than a squeeze dimension of the portion opposite to the hinge side of the annular packing seal. 
         [0015]    According to the above embodiment, although the hinge side of the annular packing seal first comes closer to the front panel of the main body casing when the door is being closed, by making the squeeze dimension due to the contact of the portion on the hinge side of the annular packing seal provided at the door (or the front panel) smaller than the squeeze dimension of the portion opposite to the hinge side, the whole annular packing seal concurrently comes in contact with the front panel of the main body casing immediately before the door is closed, and the whole annular packing seal is elastically deformed roughly similarly in the state in which the door is closed. With this arrangement, the load due to the elastic deformation of the packing seal is uniformly applied to the whole door. 
         [0016]    As is apparent from the above, according to the heating cooker of the present invention, the gap between the front panel of the main body casing and the door is uniformed in the state in which the door is closed without employing a mechanism such as a latch lock for locking the closed door, and a reliable sealing state can be maintained. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view showing an external appearance of a heating cooker of one embodiment of the present invention; 
           [0018]      FIG. 2  is a perspective view showing an external appearance in a state in which the door of the heating cooker is opened; 
           [0019]      FIGS. 3A ,  33  and  3 C are a front view, a plan view and a side view of the essential part including the door of the heating cooker; 
           [0020]      FIG. 4  is a side view showing a state on the way of opening or closing the door of the heating cooker; 
           [0021]      FIG. 5  is a sectional view of the essential part of the door viewed from the line IV-IV of  FIG. 4 ; and 
           [0022]      FIG. 6  is a sectional view of the essential part of another door viewed from the line IV-IV of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    An embodiment of the heating cooker of the present invention will now be described with reference to the accompanying drawings. 
         [0024]      FIG. 1  is a perspective view showing an external appearance of a heating cooker  1  of one embodiment of the present invention, in which a door  12  is connected to the front of a rectangular parallelepiped main body casing  10  so as to pivot roughly around its lower end side. The door  12  is provided with an operation panel  11  on the right-hand side, a handle  13  at the upper portion, and a window  14  made of a heat-resistant glass at the central portion. 
         [0025]      FIG. 2  is a perspective view showing an external appearance of the heating cooker  1  in a state in which the door  12  is opened, where a rectangular parallelepiped heating chamber  20  is provided in the main body casing  10 . The heating chamber  20  has an opening  20   a  on the front side facing the door  12 , and a side face, a bottom face and a top face of the heating chamber  20  are each formed of a stainless steel plate. Moreover, a side of the door  12  facing the heating chamber  20  is formed of a stainless steel plate. An annular packing seal  40  is attached to the rear surface side of the door  12  so as to enclose the outer periphery of the window  14  to provide a seal between the main body casing  10  and the door  12  when the door  12  is closed. By arranging a heat insulator (not shown) in the surroundings of the heating chamber  20  and inside the door  12 , heat insulation between the inside and the outside of the heating chamber  20  is achieved. 
         [0026]    Moreover, a tray  21  made of stainless steel is placed on the bottom surface of the heating chamber  20 , and a rack  22  made of stainless steel wires for carring a cooking object is put on the tray  21 . It is noted that in the opened state the upper surface of the door  12  is roughly horizontal, and the cooking object can be temporarily placed on the door  12  when taken out. 
         [0027]    Further, the main body casing  10  is provided with a water tank accommodating portion  100  for accommodating a water tank  30  at the left side of the heating chamber  20 . The water tank  30  is inserted into the water tank accommodating portion  100  from the front side toward the back side. 
         [0028]      FIG. 3A ,  FIG. 3B  and  FIG. 3C  show a front view, a plan view and a side view of the essential part including the door  12  of the heating cooker  1 , respectively. In  FIGS. 3A through 3C ,  15 ,  17 ,  18  and  19  denote a front panel, an arm, a guide roller and a guide arm, respectively. 
         [0029]      FIG. 4  shows a side view showing a state on the way of opening or closing the door  12  of the heating cooker  1 . As shown in  FIG. 4 , the front panel  15  of the main body casing  10  (shown in  FIGS. 1 and 2 ) has a roughly square frame-like shape having the opening  20   a  of the heating chamber  20 . The front end of the guide arm  19  is fixed to the lower side on both sides of the front panel  15  at a prescribed interval. The guide roller  18  is pivotably connected to the guide arm  19 . Moreover, the door  12  is supported swingably to the front panel  15  via the hinge  16 . When the door  12  is opened or closed in the direction of the arrow R, the arm  17  protrudes or retreats being guided by the guide roller  18  in accordance with the opening or closing of the door  12 . When the door  12  is opened to become roughly horizontal, the door  12  is stopped and maintained in a roughly horizontal state by a stopper mechanism (not shown) constituted of the arm  17  and the guide arm  19 . 
         [0030]    Next,  FIG. 5  shows a sectional view of the essential part of the door  12  viewed from the line IV-IV of  FIG. 4 . It is noted that  FIG. 5  shows only a door frame  41 , a door cover  42  and the annular packing seal  40  of the door  12 . It is noted that the reference numeral  15  indicated by the dashed lines denotes the front panel. 
         [0031]    As shown in  FIG. 5 , the door cover  42  is fit on the outer peripheral of the door frame  41  on the main body casing side (right-hand side of  FIG. 5 ). Moreover, the packing seal  40  is attached so as to be partially held between the door frame  41  and the door cover  42 . 
         [0032]    The annular packing seal  40  has a roughly identical cross section shape throughout the entire periphery. The annular packing seal  40  has a cross section shape having a curved portion  40   a  curved in a circular arc shape, a bent portion  40   b  that extends bending from the outer peripheral side of the curved portion  40   a,  a base portion  40   c  that extends from the inner peripheral side of the bent portion  40   b  frontward (left-hand side in  FIG. 5 ) and a groove portion  50  provided on the outer peripheral side of the base portion  40   c.  By fitting the base portion  40   c  of the annular packing seal  40  on the door frame  41  and inserting the door cover  42  into the groove portion  50 , the base portion  40   c  of the packing seal  40  is fixed held between the door frame  41  and the door cover  42 . 
         [0033]    Then, as shown in the two enlarged views (views enclosed by the circles) of  FIG. 5 , a hinge  16  side (lower side in  FIG. 5 ) of the annular packing seal  40  is positioned closer to the front surface side (left-hand side in  FIG. 5 ) by a dimension L (e.g., 0.5 mm) than the side (upper side in  FIG. 5 ) opposite to the hinge  16 . In this case, the left-hand side and the right-hand side of the annular packing seal  40  are inclined to the front surface side from the upper side to the lower side. 
         [0034]    According to the heating cooker of the above construction, the annular packing seal  40  of the roughly identically cross section shape is provided at the door  12 , and the hinge  16  side of the annular packing seal  40  is positioned closer to the front surface side than the side opposite to the hinge  16 . Therefore, even if the hinge  16  side of the annular packing seal  40  first comes closer to the front panel  15  of the main body casing  10  when the door  12  is being closed, the whole annular packing seal  40  roughly concurrently comes in contact with the front panel  15  of the main body casing  10  immediately before the door  12  is closed, and the whole annular packing seal  40  is elastically deformed roughly uniformly in the state in which the door  12  is closed. With this arrangement, a load due to the elastic deformation of the packing seal  40  is uniformly applied to the whole door. 
         [0035]    Therefore, the gap between the front panel  15  of the main body casing  10  and the door  12  is uniformed in the state in which the door  12  is closed without employing a mechanism such as a latch lock for locking the closed door  12 , and a reliable sealing state can be maintained. 
         [0036]    Although the heating cooker, in which the annular packing seal  40  is made to have the roughly identical cross section shape and the hinge  16  side of the annular packing seal  40  provided at the door  12  is positioned closer to the front surface side than the side opposite to the hinge  16 , has been described in the above embodiment, it is acceptable to provide an annular packing seal having a roughly identical cross section shape at the front panel and to position the hinge side of the packing seal closer to the back surface side than the side opposite to the hinge. 
         [0037]    Moreover, it is acceptable to provide an annular packing seal that does not have a roughly identical cross section shape at the door (or the front panel of the main body casing) and to make a squeeze dimension due to the contact of the annular packing seal on the hinge side smaller than a squeeze dimension due to the contact on the side opposite to the hinge. 
         [0038]    For example,  FIG. 6  shows a sectional view of the essential part of another door viewed from the line IV-IV of  FIG. 4 , where the door frame  41  has the same construction as that of the essential part of the door shown in  FIG. 5  except for an annular packing seal  60  and a door cover  62 . 
         [0039]    The annular packing seal  60  has a cross section shape that is not roughly identical throughout the entire circumference. The annular packing seal  60  has a cross section shape having a curved portion  60   a  curved in a circular arc shape, a bent portion  60   b  that extends bending from the outer peripheral side of the curved portion  60   a,  a base portion  60   c  that extends from the inner peripheral side of the bent portion  60   b  frontward (left-hand side in  FIG. 6 ) and a groove portion  70  provided on the outer peripheral side of the base portion  60   c.  By fitting the base portion  60   c  of the annular packing seal  60  on the door frame  41  and inserting the door cover  62  into the groove portion  70 , the base portion  60   c  of the packing seal  60  is fixed held between the door frame  41  and the door cover  62 . Then, a squeeze dimension M 2  due to the contact of the hinge side (lower side in  FIG. 6 ) of the annular packing seal  62  with the front panel  15  is made smaller by AM than a squeeze dimension M 1  due to the contact of the side (upper side in  FIG. 6 ) opposite to the hinge with the front panel  15 . With this arrangement, an effect similar to that of  FIG. 6  is performed. 
         [0040]    Furthermore, although the heating cooker, in which the door  12  is opened and closed via the hinge  16  on the lower side of the front panel  15  of the main body casing  10 , has been described in the above embodiment, the present invention may also be applied to a heating cooker or the like in which a door is opened and closed via a hinge on the right-hand or left-hand side of the front panel of the main body casing.