Patent Publication Number: US-7211775-B2

Title: Door for microwave oven permitting the efficient use of space

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional application of application Ser. No. 10/279,096, filed on Oct. 24, 2002, now U.S. Pat. No. 6,984,811 which is hereby incorporated by reference for all purposes as if fully set forth herein. This application claims the benefit of Korean Patent Application Nos. 2002-13058, filed on Mar. 11, 2002; 2002-14210, filed on Mar. 15, 2002; 2002-14212, filed on Mar. 15, 2002; and 2002-22546, filed on Apr. 24, 2002, which are hereby incorporated by reference for all purposes as if fully set forth herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a microwave oven, and more particularly, to a door for selectively closing a front surface of a microwave oven. 
   2. Discussion of the Related Art 
   Generally, microwave ovens such as those illustrated in  FIG. 1  include a door  2  arranged on a front surface of the microwave oven body  1 . Using a door handle  3 , the door  2  may be used to open and close a cooking chamber provided within the body  1 . Microwaves may be generated by various electrical devices accommodated in a device chamber provided in one side of the microwave oven body  1  and behind the controller  5 . 
   Referring to  FIGS. 1 and 2 , the controller  5  further includes a control panel  6  provided as a frame of the controller  5 . The control panel  6  generally includes, for example, a display portion  7   a  provided as a pass-through hole, a key portion  12  including a plurality of operation keys, operating buttons  13  and  13   a , and the like. A key pad  11  is provided at a front surface of pass-through hole  7   a  and a display cover  8  is provided at a rear surface of pass-through hole  7   a . Generally, both the key pad  11  and display cover  8  are formed of a transparent material. 
   Referring to  FIG. 2 , a substrate  10   a  is provided behind the control panel  6 , opposite the pass-through hole  7   a , and supports a display  10  (e.g., LED, LCD, VFD, etc.). As the display  10  is smaller in size than the pass-through hole  7   a , a gap is formed between the two components. Accordingly, a display holder  9  may be arranged between the display cover  8  and the display  10  to fill a space created by the gap. 
   The key pad  11 , provided on one region on the front of the control panel  6 , shields the key portion  12 , and includes printed information corresponding to different operation keys included within key portion  12 . Accordingly, the printed information meaningfully defines, to a user, the operation each operation key may initiate. Return spring  13   s  allows for the operation of the operation button  13 . 
   In the microwave oven illustrated in  FIGS. 1 and 2 , however, controller  5  is provided on one side of the microwave oven and in front of the device chamber. Disadvantageously, a portion of device chamber located between the various electrical devices and the controller  5  is inefficiently used and a portion of the front surface of the microwave body  1  is dedicated to the controller  5 . Moreover, since the controller  5  is provided in front the device chamber, a user may operate the operation buttons  13  or the key part  12  when door  2  is opened. If a sensing device, capable of sensing whether the door  2  is open or closed, is out of order, a safety issue arises in that the open microwave oven may be operated by the user. 
   SUMMARY OF THE INVENTION 
   An advantage of the present invention, devised for solving the foregoing problems, provides a door of a microwave oven permitting efficient use of a space of the microwave oven. 
   Another advantage of the present invention provides a door capable of preventing wrongful operation of a microwave oven. 
   The foregoing advantages of the present invention may be achieved by providing a door on a microwave oven and a control unit arranged in a predetermined portion of the door. In one aspect of the present invention, the control unit enables a user to operate the microwave oven. In another aspect of the present invention, the door may, for example, include a door unit capable of selectively opening and closing a cooking chamber, wherein the control unit is arranged in a predetermined portion of the door unit. 
   In one aspect of the present invention, the door unit may include a door frame, wherein the door frame defines an exterior shape of the door, and a door panel arranged behind the door frame, wherein the control unit is arranged on the door panel. An opening having an inner perimeter contact part extended in front and rear directions may be provided in a predetermined portion of the door frame, wherein a portion of the door panel may be exposed through the opening in the door frame. In one aspect of the present invention, the door panel may further include a projection provided within the opening, wherein the projection may couple the door panel to the door fame. 
   In another aspect of the present invention, the projection on the door panel includes an outer perimeter contact part that corresponds to the inner perimeter contact part. For example, the inner perimeter contact part of the opening includes a contact part that may contact the outer perimeter contact part. A stepped part may be arranged behind the inner perimeter contact part to form a gap with the outer perimeter contact part. 
   In yet another aspect of the present invention, the door panel may include a protruding support part arranged behind the outer perimeter contact part, wherein the protruding support part may support a rear end of the stepped part of the door frame. The door panel may further include at least one joining rib, wherein the inner perimeter contact part may be inserted between the outer perimeter contact part and the joining rib. 
   In one aspect of the present invention, the door panel may include a seat, wherein the control unit may be arranged on the seat, a display portion for displaying information, and a back surface. An operation panel, provided with a plurality of buttons allowing a user to operate the microwave oven, may be supported by a front, surface of the seat. A substrate, provided with a plurality of components enabling operation of the plurality of buttons and the display portion, may be supported on the back surface of the seat. 
   In one aspect of the present invention, the control unit may be electrically connected to a device chamber of a microwave via a connection cable included within the door of the microwave oven. Accordingly, the connection cable may connect the control unit to the device chamber via a lower portion of the door unit and a portion of a base plate of the microwave oven. The door may still further include a cover for covering a portion of the connection cable between door unit and the base plate, wherein the cover may have a height lower than a height of a leg arranged on the base plate. 
   In one aspect of the present invention, the cover may include a reception space and a door approach portion, wherein the reception space includes one opened side for receiving the connection cable and the door approach portion extends to one side of the reception space, thereby allowing the connection cable to pass through the door approach portion. In one aspect of the present invention, the door approach portion has a rounded exterior shape to prevent interference when the door is being rotated. In another aspect of the present invention, at least one holding rib may be provided in the reception space, wherein the holding rib secures the connection cable. 
   Thus, the foregoing door for a microwave oven of the present invention permits more effective use of a space of the microwave oven, and prevent wrong operation of the microwave oven. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  illustrates a perspective view of a related art microwave oven; 
       FIG. 2  illustrates an exploded perspective view of the controller in  FIG. 1 ; 
       FIG. 3  illustrates a perspective view of a microwave oven in accordance with an embodiment of the present invention; 
       FIG. 4  illustrates an exploded perspective view of the microwave oven shown in  FIG. 3 ; 
       FIG. 5  illustrates an exploded perspective view of the door shown in  FIG. 3 ; 
       FIG. 6  illustrates an exploded perspective view of a portion of a microwave oven in accordance with another embodiment of the present invention; 
       FIG. 7  illustrates a perspective view of microwave oven shown in  FIG. 6 ; 
       FIG. 8  illustrates an exploded perspective view of a door of a microwave oven in accordance with another embodiment of the present invention; 
       FIG. 9  illustrates a section view taken across a line I—I as shown in  FIG. 8 ; 
       FIG. 10  illustrates a section view corresponding to one in  FIG. 9 , showing a variation; 
       FIG. 11  illustrates a perspective partial cut-away view of a door of a microwave oven in accordance with another embodiment of the present invention; and 
       FIG. 12  illustrates a perspective partial cut-away view of a door of a microwave oven in accordance with another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     FIG. 3  illustrates a perspective view of a microwave oven in accordance with an embodiment of the present invention.  FIG. 4  illustrates an exploded perspective view of the microwave oven shown in  FIG. 3 . 
   Referring to  FIGS. 3 and 4 , a cooking chamber  32  is arranged within a cavity assembly  30  serving as a frame of the microwave oven and an electrical device chamber  31  is arranged adjacent the cooking chamber  32 . An object (e.g., food) arranged within cooking chamber  32  may be heated by radiation (e.g., microwaves) generated by various electrical devices arranged within the electrical device chamber  31 . The various electrical devices may include, for example, a magnetron  12  for generating microwaves, a high-voltage transformer  14  for supplying high voltage to the magnetron  12 , a fan  16  for generating an air flow inside the electrical device chamber  31  thereby cooling the various electrical devices as they may become heated. Further, a device substrate  31   a  may also be provided within the electrical device chamber  31 . A base plate  34  may be arranged at a bottom surface of the cavity assembly  30 . An outer case  33  may cover the cavity assembly  30  and the electrical device chamber  31 , thereby forming outside top and side exterior surfaces of the microwave oven. 
   Cooking chamber  32  may be opened or closed via door  50  attached to the microwave oven via hinge plate  30   a . The cooking chamber  32  may be closed when door  50  contacts a front surface of the cavity assembly  30 . A user may open or close the cooking chamber  32  using a door handle  52  provided on the door  50 . The door may also include a control unit and a door unit, wherein the control unit transmits signals capable of operating the microwave oven (e.g., to produce microwaves at a predetermined power level for a predetermined amount of time) and displays the operational status of the microwave oven. 
   Referring to  FIGS. 3 ,  4  and  5 , the door unit may, for example, include a door frame  53  forming the exterior surface of the door  50 , and a door panel  55  arranged behind the door frame  53 . In one aspect of the present invention, the control unit  60  may be provided on the door  50  via door panel  55 . 
   An opening may be formed in an upper central portion of the door frame  53 , through which a portion of the door panel  55  may project and thus be exposed. In one aspect of the present invention, the door panel  55  may be formed of a transparent material (e.g., transparent plastic) to enable a user to view the interior of the cooking chamber  32  from outside the microwave oven. 
   The control unit  60  may be provided at a predetermined position (e.g., an upper portion) on the door panel  55  and include an operation panel  62  and a substrate  65 . The operation panel  62  may, for example, include a display portion  63 , a plurality of buttons  62   a  enabling a user to operate the microwave oven, and a flexible cable  64  for transmitting signals between the buttons  62   a  and a plurality of components supported by substrate  65 . Substrate  65  may, for example, support a display  66  for displaying information within the display portion  63 , connectors  67  for electrically connecting to the flexible cable  64 , and a connection cable  68  for electrically connecting the control unit  60  to the components in the electrical device chamber  31 . 
   Control unit  60  may be seated on the door panel  55  via a seat  56 . Seat  56  may be laterally arranged in, and project outwardly from, an upper portion of the door panel  55 . A display portion pass-through hole  56   h  may be centrally arranged within seat  56  and a cable slot  56   s  may be arranged at a side portion of seat  56 . 
   The operation panel  62  may be arranged on a front surface of seat  56 , while the substrate  65  may be arranged on a rear surface of the seat  56 . Once arranged on the seat  56 , the location of the display portion  63  on the operation panel  62  corresponds to the location of the display portion pass-through hole  56   h  and the flexible cable  64  may extend through the cable slot  56   s  toward the back of the door panel  55  and connect to the connector  67  of substrate  65 . Once assembled, information generated by display  66  may be shown through display part  63  and operation signals may be transmitted between the operation panel  62  and the substrate  65  via flexible cable  64  and connector  67 . 
   According to the principles of the present invention, since control unit  60  may be arranged on the door  50 , space located in a front portion of the electrical device chamber may be used for purposes generally not recognized by microwave ovens such as those illustrated in  FIGS. 1 and 2 . For example, devices other than those used in the heating of objects with microwaves may be provided within the front portion of the electrical device chamber. Devices such as toasters, coffee makers, and the like, may be incorporated into the microwave oven of the present invention without increasing the size of the microwave oven. In one example shown in  FIGS. 3 and 4 , a toaster  40  may be arranged at the front portion of the electrical device chamber  31 . Accordingly, a toaster. body  49  may be arranged within the electrical device chamber  31  and a toaster door  48 , for selective opening/closing the toaster  40 , may be arranged at a front portion of the toaster body  49 . 
   In order to operate the microwave oven according to the principles of the present invention, a user must, for example, press button  63   a  on the operation panel  62 . In pressing button  63   a , the user is required to apply a force to the operation panel  62 . If the door  50  is opened, however, it is difficult to apply a force sufficient to press button  63   a  and therefore operate the microwave oven. Button  63   a , however, may only be pressed with sufficient force when the door  50  is closed. Accordingly, the principles of the present invention may prevent the microwave oven from being operated when the door  50  is opened, either through the user or through a malfunction of a sensing device. 
   As mentioned above, connection cable  68  is located between and electrically connects, the control unit  60  and various electrical devices within the electrical device chamber  31 . In the present invention, connection cable  68  may be guided along a coupling part of the door  50  and the body of the microwave oven, exposed at a lower part of the microwave oven, and inserted into the base plate  34 . Accordingly, a portion of the connection cable  68  may be exposed to the outside at a location between the door  50  and the body of the microwave oven. Being exposed, the connection cable  68  may be vulnerable to damage (e.g., breakage). 
   With reference now to  FIGS. 4 ,  6  and  7 , the connection cable  68  may electrically connect the substrate  65  of the control unit  60  to substrate  31   a , or other various electrical devices, within the electrical device chamber  31  or microwave oven in such a way as to minimize damage it could potentially incur. 
   In one aspect of the present invention, connection cable  68  may be guided from the substrate  65 , through a cut-away portion  50   a  formed in a bottom surface of the door  50 , through a pass-through hole  34   s  formed in base plate  34 , and into the body of the microwave oven. According to the present invention, pass-through hole  34   s  may be arranged within a side portion of base plate  34  at the same side of the microwave oven as hinge plate  30   a . The connection cable  68  may be arranged within the body of the microwave oven in a space defined between the outer case  33  and the cavity assembly  30 . 
   The portion of the connection cable  68  that is exposed between the cut away part  50   a  in the door  50  and the pass through hole  34   s  in the base plate  34  may be covered with cover  70 . In one aspect of the present invention, cover  70  may be hexahedral. In another aspect of the present invention, cover  70  may include a side arranged opposite the bottom of the base plate  34  is open such that cover  70  forms a reception space  71  capable of receiving the connection cable  68 . Additionally, reception space  71  may include at least one holding rib  77  for holding the connecting cable  68 . In one aspect of the present invention, holding rib  77  may exhibit a ‘┐’ form, substantially. In another aspect of the present invention, holding ribs  77  may be formed such that fore ends of the holding ribs are alternately extended in opposite directions. 
   In one aspect of the present invention, a door approach portion  73 , extending toward door  50 , is provided at one end of cover  70  located at the cut-away part  50   a  at the bottom of door  50 . In another aspect of the present invention, the cut-away part  50   a  and the door approach portion  73  are rounded so as to minimize the degree to which the two components interfere with each other when the door  50  is opened and closed. 
   The door approach portion  73  includes a fore end having a connection cable lead-out opening  74 . The connection cable lead-out opening  74  has an opened side formed to be in communication with an interior space of the door  50  at the cut-away part  50   a.    
   The cover  70  includes a fastening rib  75  formed so as to project into the reception space  71  and be recessed in an exterior surface of the cover  70 . Cover  70  may be secured to the base plate  34  by fastening a screw  76  to a fastening hole  34   h  in the base plate  34  through a fastening hole  75   a  arranged within fastening rib  75 . 
   Legs  60  may be arranged at the bottom surface of, and coupled to, the base plate  34  to form a gap between the microwave oven and the surface on which the microwave oven is arranged. In one aspect of the present invention, the height of the gap between the microwave oven and the surface may be greater that the height of cover  70 . 
   According to the principles of the present invention, the portion of the connection cable  68  located between door  50  and base plate  34  may be concealed by the cover  70 . Thus, any damage that may be incurred by the portion of the connection cable  68  located between the door  50  and the body of the microwave oven may be minimized. 
   Referring now to  FIGS. 8 and 9 , door  50  according to one embodiment of the microwave oven of the present invention will now be explained. 
   As described above, the door  50  may include a door frame  53  and a door panel  55 . A metallic frame part  16  forms a frame support structure for the entire door  50 . A choke structure  16   a  may be provided at a rear edge of the metallic frame part  16  to prevent leakage microwaves generated within the cooking chamber  32 . A cover  18  may be provided adjacent a rear edge of the choke structure  16   a.    
   According to one aspect of the present invention, an opening  53   a , defined by an inner perimeter contact part  53   b  extended in front and rear directions, may be formed in an upper central portion of the door frame  53 , wherein the door panel  55  is coupled to rear of the opening  53   a . A projected part  55   a , defined by an outer perimeter contact part  55   b , may be formed in door panel  55 , wherein the projected part  55   a  may be inserted into the opening  53   a  of the door frame  53 . 
   When the projected part  55   a  of the door panel  55  is inserted into the opening  53   a , the inner perimeter contact part  53   b  and the outer perimeter contact part  55   b  are brought into contact. 
   Referring now to  FIGS. 10 and 11 , door  50  according to another embodiment of the microwave oven of the present invention will now be explained. 
   According to the present embodiment of the invention, the door frame  53  and the door panel  55  may be provided substantially as described with reference to  FIGS. 8 and 9 , however, the portions of the door frame  53  and of the door panel  55  that contact each other differ. 
   For example, while door panel  55  includes a projected part  55   a , defined by the outer perimeter part  55   b , to be inserted in the opening  53   a  of the door frame  53 , door panel  55  further includes a support part  55   c  arranged behind the outer perimeter contact part  55   b  and extended in radial directions. 
   Additionally, while door frame  53  includes an opening  53   a  defined by the inner perimeter contact part  53   b , the door frame  53  further includes a contact part  531 , provided so as to contact the outer perimeter contact part  55   b , and a stepped part  533 , provided so as not to contact the door panel  55 . In one aspect of the present embodiment, contact part  531  has a first length, L 1 , that is shorter than a second length, L 2 , of the stepped part  533 . 
   Accordingly, when the projected part  55   a  of the door panel  55  is inserted into the opening  53   a , the contact part  531  of the inner perimeter contact part  53   b  contacts, and is inserted into, the outer perimeter contact part  55   b  while the stepped part  533  does not contact the outer perimeter contact part  55   b  to form a gap therebetween. In one aspect of the present invention, a rear end  535  of the inner perimeter contact part  53   a  contacts the support part  55   c  of the door panel  55 . Accordingly, the rear end  535  contacts the support part  55   c  and facilitates the door panel  55  to contact the door frame  53 . 
   According to the present embodiment, in assembling the door frame  53  with the door panel  55 , the first length, L 1 , of contact is shorter than the second length, L 2 , of no contact. Accordingly, the door frame  53  and the door panel  55  may be assembled after they come into contact over a comparatively short length, L 1 . 
   According to the present invention, the inner perimeter contact part  53   b  of the door frame and the outer perimeter contact part  55   b  of the door panel may be brought into contact in over a first length, L 1 . Therefore, assembly of the door frame  53  and the door panel  55  is simple, and any noise caused by contact between the two components after they are assembled may be reduced. Moreover, even if contact area between the two components is reduced, the contact of the rear end  535  with the support part  55   c  may provide a robust door assembly as the rear end  535  and the support part  55   c  make close contact even in an assembly state. 
   Referring now to  FIG. 12 , door  50  according to yet another embodiment of the microwave oven of the present invention will now be explained. 
   According to the present embodiment of the invention, the door frame  53  and the door panel  55  may be provided substantially as described with reference to  FIGS. 10 and 11 , however, the present embodiment additionally includes a joining rib  90  for coupling of the door frame  53  to the door panel  55 . 
   Accordingly, the door panel  55  includes a joining rib  90  projected forward from an outer surface of the support part  55   c . The joining rib  90  extends forward from the outside outer perimeter surface  55   d  and backward from the support part  55   c  such that a gap is provided from the joining rib  90  to the outer perimeter contact part  55   b . In one aspect of the present embodiment, a plurality of the joining parts  90  may be provided at predetermined intervals along the entire outer perimeter surface of the projected part  55   a.    
   The door assembly of the present embodiment facilitates insertion of the inner perimeter contact part  53   b  between the joining ribs  90  and the outer perimeter contact part  55   b . For example, when the door panel  55  is joined to the rear of the door frame  53 , the inner perimeter contact part  53   b  is inserted between the outer perimeter contact part  55   b  and the joining ribs  90 . Moreover, if a plurality of the joining ribs  90  are formed on an outer perimeter surface of the projected part  55   a , the inner perimeter contact part  53   b  may be inserted between the joining ribs  90  and the outer perimeter contact part  55   b.    
   According to the present invention, if an external force is applied to the door frame  53  or the door panel  55  after the two components are coupled together, the assembly of the door frame and door panel may be maintained. Moreover, the secure coupling of the door frame  53  and the door panel  55  prevents deformation of the door frame  53  or the door panel  55  due to heat generated inside the cooking chamber  32  and relative movement between the door frame  53  and door panel  55 .