Patent Publication Number: US-6222171-B1

Title: Cooking appliance that can be easily installed by small man labor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cooking appliance, and a method of installing this cooking appliance. More particularly, the present invention relates to a high-placement type cooking appliance such as a microwave oven attached at a high position to a wall or within a cabinet in a kitchen, and a method of installing this cooking appliance. 
     2. Description of the Background Art 
     Installing the cooking appliance at a wall or within a cabinet in a kitchen is advantageous from the standpoint of effectively using limited space. Such a cooking appliance attached at a high position to a wall or installed within a cabinet is referred to as a high-placement type cooking appliance hereinafter. 
     This high-placement type cooking appliance is disadvantageous in that the installment job is difficult. 
     In the case of installing a cooking appliance to the wall, for example, great man labor is required since the installation includes the supporting job and the attaching job, as shown in FIGS. 36A and 36B. More specifically, two workmen are required to engage the fastening member of a cooking appliance  100  with a predetermined portion of a wall  110  while supporting cooking appliance  100 , as shown in FIG.  36 A. Referring to FIG. 36B, the two workmen attach cooking appliance  100  to wall  110  while supporting cooking appliance  100 . It is appreciated from these drawings that at least two workmen are required in the conventional installment of a cooking appliance corresponding to the supporting job and the attaching job. A great man labor was required in the conventional installment of a cooking appliance. It was not easy to handle a cooking appliance. 
     The conventional high-placement type cooking appliance is also disadvantageous in that the repair of the internal components constituting the control means requires great man power. When an internal component is to be removed for repair, the cooking appliance attached to the wall had to be dismounted to remove the internal component. Alternatively, the front panel of the cooking appliance attached to the wall had to be removed. Then, the internal component secured at a predetermined location inside the cooking appliance had to be removed through the opening. In other words, the conventional cooking appliance required the step of dismounting the cooking appliance per se or a predetermined panel, and also the step of removing the internal component from a predetermined location in the cooking appliance. The internal component could be repaired only through the load of great man labor. The conventional cooking appliance could not be handled easily. 
     The interior of the conventional cooking appliance becomes higher in temperature than the room temperature since a cooking operation such as heating foodstuff is carried out. The conventional cooking appliance includes an inlet and an outlet to introduce the air into the cooking appliance for cooling the interior and to exhaust the air in the cooking appliance outside. 
     In the conventional cooking appliance, the inlet and the outlet are open even when the air is not introduced or output. There was a problem that dust and contamination will be introduced into the cooking appliance through the inlet or the outlet even when the operation of air input and output is not carried out in the conventional cooking appliance. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, an object of the present invention is to provide a cooking appliance that can be handled easily. 
     Another object of the present invention is to provide a method of easily installing a cooking appliance. 
     A further object of the present invention is to provide a cooking appliance into which dust and contamination do not easily enter. 
     According to an aspect of the present invention, a cooking appliance includes a heat unit for heating foodstuff, a controller for controlling the operation of the heat unit, and a casing enclosing the heat unit and the controller. The cooking appliance is attached to a fixture panel fixed to a sidewall. The casing includes a bottom panel located at the bottom of the casing, and a body frame covering the upper portion of the bottom panel. The controller is provided on the bottom panel. The bottom panel is detachable from the body frame with the cooking appliance still attached to the fixture panel. 
     It is to be noted that the bottom panel can be detached from the body frame while the cooking appliance is still attached to the fixture panel. In other words, the controller can be detached from the body frame with the cooking appliance still attached to the fixture panel. 
     Since the controller can be easily removed from the cooking appliance, the internal components constituting the controller can be repaired, if necessary, more easily. Thus, a cooking appliance feasible in handling can be provided. 
     According to another aspect of the present invention, a method of installing a cooking appliance having a fastening member engaging with a fixture panel fixed to a sidewall includes the steps of setting the cooking appliance at a first state in which the cooking appliance is tilted forward in front of the sidewall on a predetermined base, setting the cooking appliance at a second state from the first state in which the cooling appliance is tilted forward and having the fastening member engaging with the fixture panel, setting the cooking appliance at a third state in which the forward tilt is less than in the second state by rotating the cooking appliance about the fastening member from the second state, and fixing the cooking appliance attaining the third state to the fixture panel. In the step of fixing the cooking appliance attaining the third state to the fixture panel, the cooking appliance attaining the third state is supported using a predetermined member. 
     The cooking appliance is supported at the third state by a predetermined member in the transition from the second state to the third state. 
     Accordingly, the labor involved in the supporting job as to the supporting job and the attaching job required in the installment of the cooking appliance can be reduced. Therefore, the method of handling the cooking appliance easily can be provided. 
     In the method of installing the cooking appliance, the predetermined member is preferably a support base to support the cooking appliance attaining the third state. 
     The cooking appliance is supported at the third state by the support base in the transition from the second state to the third state. Therefore, the labor involved in the supporting job as to the supporting job and the attaching job required in the installment of the cooking appliance can be reduced. 
     In the method of installing the cooking appliance, the predetermined member is preferably a sub fastening member provided at the cooking appliance, and engaging with the fixture panel when the cooking appliance is at the third state. 
     The cooking appliance is supported at the third state by the engagement of the sub fastening member with the fixture panel in the transition from the second state to the third state. 
     Therefore, the labor involved in the supporting job as to the supporting job and the attaching job required in the installment of the cooking appliance can be reduced. 
     According to a further aspect of the present invention, a method of installing a cooking appliance having a fastening member engaging with a fixture panel fixed to a sidewall includes the steps of setting the cooking appliance at a first state in which the cooking appliance is tilted forward on a predetermined base in front of the sidewall, setting the cooling appliance at a second state from the first state in which the cooking appliance is tilted forward and having the fastening member being engaged with the fixture panel, and setting the cooking appliance at a third state in which the forward tilt is less than that in the second state by rotating the cooking appliance about the fastening member from the second state, and fixing the cooking appliance attaining the third state to the fixture panel. In the step of setting the cooking appliance at a first state, a support member supporting a cooling appliance attaining the first state is used. 
     In the step of setting the cooking appliance at the first state, the cooking appliance is supported at the first state by the support member. 
     Accordingly, the labor involved in the supporting job as to the supporting job and the attaching job required in the installment of the cooking appliance can be reduced. Therefore, a cooking appliance that can be handled easily can be provided. 
     In the method of installing the cooking appliance, the step of setting the cooking appliance at the second state preferably includes the step of sliding the cooking appliance on a predetermined base with a predetermined plate sandwiched between the predetermined base and the cooking appliance. 
     In sliding the cooking appliance on the predetermined base to attain the second state, a predetermined plate is sandwiched between the predetermined base and the cooking appliance. 
     This facilitates the sliding of the cooking appliance. Therefore, the labor involved in the supporting job as to the supporting job and the attaching job required in the installment of the cooking appliance can be reduced. 
     According to still another aspect of the present invention, a cooking appliance including an inlet to admit air into the cooking appliance and an outlet to exhaust air outside the cooking appliance has a cover that can be opened and closed extending over the inlet and the outlet. 
     When the operation of air input and output is not carried out in the cooking appliance, the inlet and the outlet can be covered by means of the cover. 
     Thus, the opportunity of dust and contamination being introduced into the cooking appliance can be reduced. A cooking appliance into which dust and contamination do not easily enter can be provided. 
     The cover preferably includes a partition member that prevents the air input into the cooking appliance through the inlet from being mixed with the air output from the cooking appliance through the outlet when the cover is open. 
     Accordingly, mixture of input air and output air can be prevented in the cooking appliance when the cover is open. Therefore, when air input and output is carried out for cooling the interior of the cooking appliance, introduction of the discharged warm air can be avoided to improve the cooling efficiency. 
     Further preferably, the cooking appliance includes a fan to input air through the inlet and to output air through the outlet, and a fan-oriented controller that controls the open/close state of the cover according to the operational status of the fan. 
     By virtue of the fan-oriented controller, the cover is automatically opened/closed according to the fan operational status. 
     Since the open/close state of the cover is switched automatically in an appropriate manner in the cooking appliance, the usability of the cooking appliance is improved. 
     Further preferably, the cooking appliance includes a heat unit for heating an object, and a heat-oriented controller for controlling the open/close state of the cover according to the operational status of the heat unit. 
     By virtue of the heat-oriented controller, the cover is opened/closed automatically according to the operational status of the heat unit. 
     Since the open/close state of the cover is switched automatically in an appropriate manner in the cooling appliance, usability thereof is improved. 
     According to a still further aspect of the present invention, a cooking appliance includes a heat unit for heating foodstuff, a controller for controlling the operation of the heat unit, and a casing enclosing the heat unit and the controller. The cooking appliance is attached to a fixture panel fixed to a sidewall. The cooking appliance includes an elongated aperture at the back side of the casing. An angle member fitting into the elongated aperture at the back side of the casing to support the casing is provided perpendicular at both sides of the fixture panel. Also, a hook supporting the bottom panel of the casing is provided at the lower edge portion of the fixture panel. An inclination portion and a horizontal portion continuous thereto are formed as a guide at the upper edge portion of the angle member to guide the upper edge obliquely upwards through the elongated aperture when the casing is to be attached to the fixture panel. 
     Preferably, the angle member includes an engage convex portion between the inclination portion and the horizontal portion to prevent the casing from being detached from the angle member through the elongated aperture. 
     According to yet a further aspect of the present invention, a method of installing a cooking appliance having a heat unit heating a foodstuff, a controller controlling the operation of the heat unit, and a casing enclosing the heat unit and the controller attached to a fixture panel fixed to a sidewall includes the steps of passing an angle member provided perpendicular at both sides of the fixture panel through an elongated aperture provided at the back side of the casing, moving the casing obliquely upwards along an inclination portion formed at the angle member, engaging an upper edge of the elongated aperture with an engage convex portion formed between the inclination portion and the horizontal portion of the angle member at the termination of the obliquely upward movement of the casing and supporting the bottom panel of the casing at the hook provided at the lower edge portion of the fixture panel, and setting the back side of the casing along the fixture panel by rotating the casing about the hook. 
     Further preferably, the method of installing a cooking appliance includes the step of moving the casing on a predetermined base having a slope upwards and obliquely along the inclination portion formed at the angle member. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A and 1B show a microwave oven according to an embodiment of the present invention. 
     FIGS. 2A and 2B are diagrams to describe the structure of the microwave oven in detail. 
     FIG. 3 schematically shows an electric circuit of the microwave oven. 
     FIG. 4 is a diagram to describe in detail the structure of the microwave oven. 
     FIGS. 5-7 are diagrams to describe installment of the microwave oven at a high position. 
     FIG. 8 is a diagram to describe the procedure of preparing a support base, an upright portion, and an underlying panel used in installing the microwave oven. 
     FIGS. 9A and 9B are diagrams to describe the procedure of preparing a support base, an upright portion, and an underlying panel used in installing the microwave oven. 
     FIGS. 10A and 10B are diagrams to describe the procedure of preparing a support base, an upright portion, an underlying panel, and an insert member used in installing the microwave oven. 
     FIGS. 11-12 are diagrams to describe a modification of installing a microwave oven at a high position. 
     FIG. 13 shows a modification of a microwave oven. 
     FIG. 14 is a perspective view of a structure of a microwave oven according to a second embodiment of the present invention. 
     FIGS. 15-19 are side views of the microwave oven of the second embodiment to describe installment at a high position. 
     FIG. 20 shows a microwave oven according to a third embodiment of the present invention. 
     FIG. 21 shows the microwave oven of FIG. 20 with the door open. 
     FIG. 22 is a sectional view of the microwave oven of FIG. 20 taken along line XXII-XXII. 
     FIGS. 23 and 24 are perspective views of the microwave oven of the third embodiment. 
     FIG. 25 is an enlargement view of the right upper portion of the microwave oven of the third embodiment. 
     FIG. 26 is a plan view of the microwave oven of the third embodiment with the outer portion of the main body omitted. 
     FIG. 27 is an enlargement view of the microwave oven of the third embodiment in the proximity of the partition panel. 
     FIG. 28 is an enlargement view of the microwave oven of the third embodiment in the proximity of the connection member. 
     FIG. 29 is a control block diagram of the microwave oven of the third embodiment. 
     FIG. 30 shows a control panel of the microwave oven of the third embodiment. 
     FIGS. 31,  32 , and  33  are diagrams to describe the air flow direction of the hood fan in the microwave oven of the third embodiment. 
     FIG. 34 is a flow chart of the cover open/close process of the microwave oven of the third embodiment. 
     FIG. 35 is a flow chart of a modification of the cover open/close process. 
     FIGS. 36A and 36B are diagrams to describe the installment of a conventional high-placement type cooking appliance to a wall. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described hereinafter with reference to the drawings. 
     (1) First Embodiment 
     Referring to FIGS. 1A and 1B, a microwave oven  1  has its contour covered with a body frame  4 . Microwave oven  1  includes a control panel  2 , a door  3 , and an air port  4   a  at the front. Microwave oven  1  is generally mounted within a cabinet  5  right above a gas range  6 . 
     Referring to FIG. 2A, a kitchen lamp  31  and a kitchen lamp  32  are provided at the bottom of microwave oven  1 . The user can turn on kitchen lamps  31  and  32  during the cooking operation of gas range  6 . 
     FIG. 2B is a diagram to describe the interior structure of microwave oven  1 , with panel  2 , door  3 , and the front panel of air port  4   a  removed. Referring to FIG. 2B, a heat chamber  7  in which an object to be heated such as foodstuff is accommodated behind door  3 . An interior lamp  28  is provided above heat chamber  7  to light up the interior of heat chamber  7 . Heat resisting glass  33  and heat resistance glass  34  are provided beneath kitchen lamp  31  and kitchen lamp  32 , respectively. 
     FIG. 3 schematically shows the electrical circuit of microwave oven  1 . Referring to FIG. 3, an AC power supply  20  supplies power to a magnetron  10 , a high voltage transformer  11 , a high voltage diode  12 , and a high voltage capacitor  13  constituting the circuitry shown in FIG. 3. A half wave double voltage circuit is constituted by high voltage transformer  11 , high voltage diode  12  and high voltage capacitor  13  to supply a high voltage (3-4 kV) to magnetron  10 .  14  designates the discharge resistor discharging the charge accumulated at high voltage capacitor  13  after supply to magnetron  10  is ceased. As to discharge resistance  14 , a resistor having a resistance so that discharge of high voltage capacitor  13  is completed by appropriately one minute after the power is cut is employed. 
     A door switch  15  is provided to open and close the circuitry shown in FIG. 3 when door  3  is open and closed, respectively. Therefore, microwave oven  1  is implemented to inhibit generation of an electric wave from magnetron  10  when door  3  is open since the circuitry is open by door switch  15 . Supply of current from AC power supply  20  to transformer  11  is suppressed in this way. 
       18  and  19  designate an output adjustment relay and a main relay regulating energization of magnetron  10 , respectively, for the heat cooking operation. Main relay  19  is ON during the heating operation. Output adjustment relay  18  is repeatedly turned on/off during the heating operation to adjust the output of magnetron  10 . The on/off operation of output adjustment relay  18  and main relay  19  is under control of control circuit  21 . 
     Control circuit  21  includes a microcomputer and a memory not shown. Control circuit  21  turns on/off main relay  19  and output adjustment relay  18  according to the cooking menu input by the user through control panel  6  by the microcomputer. Control circuit  21  stores the cooking information such as the heating time, if necessary, into the memory.  22  designates a constant voltage circuit supplying power of a constant voltage to control circuit  21 . 
       17  designates a monitor switch functioning in a manner opposite to door switch  15 . More specificaily, monitor switch  17  is implemented to close and open the circuitry shown in FIG. 3 when door  3  is opened and closed, respectively. Monitor switch  17  functions to form a short-circuit to cut a fuse  23  to avoid energization towards magnetron  10  when door switch  15  does not open the circuitry due to some cause even when door  3  is opened. Thus, the dangerous status of magnetron  10  emitting an electric wave of high frequency with door  3  open can be obviated. 
       26  designates a blower motor to drive the cooling fan of magnetron  10 .  28  designates an interior lamp lighting the interior of heat chamber  7 .  27  designates a relay switch controlling energization towards blower motor  26  and interior lamp  28 . Relay switch  27  is turned on/off under control of control circuit  21 . 
     Kitchen lamps  31  and  32  are connected to constant voltage circuit  22 .  80  designates a relay switch controlling energization towards kitchen lamp  31  and  32 . Relay switch  80  is turned on/off under control of control circuit  21  in response to a predetermined manipulation by the user through control panel  60 . 
     FIG. 4 is a diagram to describe the structure of microwave oven  1  of FIG. 1 in detail. FIG. 4 is a side view of microwave oven  1  with the right end portion of body frame  4  removed. 
     Upon initiation of the operation of blower motor  26  in microwave oven  1  of FIG. 4, air is admitted from the front of microwave oven  1  to result in air flow from blower motor  26  towards magnetron  10  and a duct  29 , as indicated by the chain dotted arrow. Duct  29  communicates with heat chamber  7 . The air flowing into duct  29  is sent to the interior of heat chamber  7 . By this air flow, high voltage capacitor  13 , high voltage transformer  11  and magnetron  10  are cooled during the cooking operation using magnetron  10  in microwave oven  1 . 
     Many of the electronic components forming the circuitry shown in FIG. 3 such as high voltage transformer  11  and high voltage capacitor  13  are provided on a bottom panel  41  forming the bottom of body frame  4  at the bottom of microwave oven  1 . A filter  25  is fitted under bottom panel  41  in microwave oven  1 . By removing filter  25  and small screws  42  and  43 , bottom panel  41  can be moved downwards to be detached from body frame  4  of microwave oven  1 . By removing bottom panel  41  from body frame  4  of microwave oven  1 , many of the electronic components forming the circuitry shown in FIG. 3 such as high voltage transformer  11  and high voltage capacitor  13  can be detached from the main body of microwave oven  1 . Since bottom panel  41  can be removed from the main body of microwave oven  1 , the electronic components of microwave oven  1  can be easily detached from the body of microwave oven  1 . 
     Electronic components such as magnetron  10  that are not provided on bottom panel  41  can also be easily detached by removing filter  25  and bottom panel  41 . More specifically, the workman can insert one&#39;s hand from the bottom of microwave oven  1  to remove a relevant component. 
     Since many electronic components can be detached from below microwave oven  1 , repair of an electronic component of microwave oven  1  is facilitated when microwave oven  1  is attached at a high location as shown in FIG.  1 B. 
     The method of installing microwave oven  1  at a high position as shown in FIG. 1B will be described hereinafter. 
     Referring to FIG. 5, a support base  51  is placed on gas range  6  to tilt microwave oven  1  forward in front of cabinet  5  in installing microwave oven  1  at cabinet  5 . A member  52  supporting microwave oven  1  in a forward tilting posture at the front side on support base  51  is provided. Microwave oven  1  is supported to avoid sliding off support base  51  by virtue of member  52 . 
     The workman then slides microwave oven  1  on support base  51  towards cabinet  5  (in the direction of arrow G in FIG. 6) from the stage shown in FIG. 5, whereby the rear lower portion of microwave oven  1  is to be caught on a hook  60  provided on the wall of cabinet  5 . FIG. 6A corresponds to this state. In the present embodiment, an underlying panel  53  is inserted between support base  51  and microwave oven  1  to slide microwave oven  1 . This facilitates the slide of microwave oven  1  on support base  51 . Therefore, the sliding job can be carried out more easily. Underlying panel  53  is formed of, for example, cardboard and the like. The state of the rear lower end of microwave oven  1  caught on hood  60  is represented by a region VIB in FIG.  6 A. FIG. 6B corresponds to an enlarged view of region VIB. 
     Next, the workman rotates microwave oven  1  in the direction of arrow R about the contact between hook  60  and microwave oven  1  within region VIB, as shown in FIG.  6 A. As a result, microwave oven  1  takes a posture facing the front, as shown in FIG.  7 . Microwave oven  1  is secured to cabinet  5  by means of a small screw in the front-facing state. Thus, the installment job of microwave oven  1  to cabinet  5  is completed. In order to secure microwave oven  1  at the front-facing state in the fixing operation by means of the small screw, a driver  40  is inserted into a hole provided at a predetermined position in microwave oven  1  through an opening provided at a predetermined position in cabinet  5 . Also, an insert member  54  is fitted between microwave oven  1  and support base  51  to fix microwave oven  1  at the front-facing state in the fixing operation by means of the small screw. Little, if any, force is required by the workman to support microwave oven  1  in the fixing operation through the small screw. Therefore, the workman can mount microwave oven  1  at cabinet  5  more easily. 
     Support base  51 , member  52  and underlying panel  53  used in installing microwave oven  1  can be formed of a cardboard that is used for the package of microwave oven  1 . The procedure of preparing support base  51 , upright member  52 , and underlying panel  53  from the cardboard box will be described hereinafter. 
     Referring to FIG. 8, the lower portion of cardboard box  50  is cut along a cut away line  55 . Accordingly, cardboard box  51  is divided into an upper portion  56  shown in FIG. 9A and a lower portion  57  shown in FIG.  9 B. Referring to FIG. 9A, upper portion  56  is cut along a cut away line  56   a . The upper portion thereof corresponds to support base  51  shown in FIG.  10 A. By providing a cut according to a cut line  56   b  and a cut line  56   c  at the upper face of upper portion  56  of FIG. 9A, and bending up the cut portion, two upright members  52  as shown in FIG. 10A are provided in support base  51 . 
     Lower portion  57  of FIG. 9B is further cut along a cut away line  57   a . The front portion thereof corresponds to underlying panel  53 , as shown in FIG.  10 B. 
     Insert member  54  can be formed using expanded polystyrene or the like employed to fill the gap between the cardboard box and microwave oven  1  in the package of microwave oven  1 . 
     A modification of the method of installing microwave oven  1  at cabinet  5  will be described hereinafter. In the previous installment of microwave oven  1 , microwave oven  1  facing the front was supported by an insert member  54  as shown in FIG.  7 . The present invention is not limited to this embodiment. For example, a hook  30  can be provided at the back side of microwave oven  1 . Also, an engage member  61  can be provided at a predetermined position on cabinet  5  corresponding to hook  30 , as shown in a region P in FIG.  11 . By these members, hook  30  engages with engage member  61  when microwave oven  1  is pivoted in the direction of R from the state shown in FIG. 11 about the contact with hook  60 . By virtue of this engagement, microwave oven  1  is supported in a front-facing posture even if insert member  54  is absent. FIG. 12 represents an enlarged view of the engagement between hook  30  and engage member  61 . In FIG. 12, the engaging state of hook  30  and engage member  61  is represented by the solid line. The state right before engagement is represented by the broken line. Hook  30  and engage member  61  attain the state indicated by the solid line when microwave oven  1  is set at the state of FIG. 7 facing the front. 
     A modification of the structure of microwave oven  1  per se will be described. As described with reference to FIG. 2B, microwave oven  1  includes the three lamps of kitchen lamp  31 , kitchen lamp  32 , and interior lamp  28 . Kitchen lamp  32  is dispensable by mounting interior lamp  28  below heat chamber  7 , as shown in FIG.  13 . Since interior lamp  28  must light heating chamber  7  from below of heat chamber  7 , a portion of the bottom (corresponding to interior lamp  28 ) of heat chamber  7  must be formed of a transparent material such as heat resisting glass  71 . Since the number of lamps of microwave oven  1  can be reduced by this structure, microwave oven  1  can be fabricated at a lower cost. 
     (2) Second Embodiment 
     FIG. 14 is a perspective view of a microwave oven  1  according to the second embodiment of the present invention, viewed from the back side. Referring to FIG. 14, one pair of elongated apertures  107   a  and  107   b  are formed at both side ends at the back face of microwave oven  100 . Each elongated aperture has the longer size running in the vertical direction. 
     An installment structure and a method of installing microwave oven  100  at a high location as shown in FIG. 1 will be described hereinafter. 
     Referring to FIG. 15, when microwave oven  100  is to be attached to cabinet  5 , support base  51  for tilting microwave oven  1  forward in front of cabinet  5  is placed on gas range  6 , likewise the first embodiment. 
     Only one workman is required to slide microwave oven  1  on support base  51  towards cabinet  5  (in the direction of arrow G in FIG. 15) from the state of FIG.  15 . An upper edge inclination portion  82   a  of an angle member  82  provided perpendicularly at both side edges of a fixture panel  108  fixed at a wall  56  of the kitchen in the proximity of cabinet  5  passes through respective elongated apertures  107   a  and  107   b  at the back side of microwave oven  100 , whereby an upper edge  71   a  of the elongated aperture slides on upper edge inclination portion  82   a . A hook  81  engaging with the back lower portion of microwave oven  100  is provided at wall  56 , likewise the first embodiment. 
     Support base  51  is formed of a cardboard box used for packaging microwave oven  1 , likewise the first embodiment. 
     Accordingly, microwave oven  1  moves upwards obliquely while sliding on support base  51  with the back side pulled upwards by upper edge inclination portion  82   a  of angle member  82 . 
     FIG. 16 shows the final state of microwave oven  100  in the travel of the oblique direction. Here, the lower portion at the back side of microwave oven  100  abuts against the lower edge of fixture panel  108 . Here, the distance from the lower end of the back face of microwave oven  100  to an engage convex portion  82   c  located between upper edge inclination portion  82   a  and horizontal portion  82   b  is X. The distance from hook  81  to engage convex portion  82   c  is X+α. Therefore, the lower end of the back side of microwave oven  1  is located upper of hook  81 . 
     By rotating microwave oven  100  in the direction of arrow R with the lower end of the back side of microwave oven  1  as the fulcrum, the lower end of the back side of microwave oven  100  descends by distance α. As a result, upper edge portion  71   a  of elongated aperture  7   a  engages with engage convex portion  82   c  located between upper edge inclination portion  82   a  and horizontal portion  82   b  of angle member  82 , as shown in FIG.  17 . 
     Therefore, microwave oven  100  is provisionally secured by angle member  82  and hook  81  in this state. Microwave oven  100  will not fall off even when the workman releases one&#39;s hand. 
     Then, microwave oven  100  is pivoted downwards with upper edge portion  71   a  of elongated aperture  107   a  sliding along horizontal portion  82   b  of angle member  82 . Thus, the back face of microwave oven  100  exactly fits along fixture panel  108 , as shown in FIGS. 18 and 19. 
     By securing the upper panel of body frame  4  of microwave oven  100  to the bottom panel of cabinet  5 , the installment process is completed. 
     (3) Third Embodiment 
     The cooking appliance according to the third embodiment of the present invention is not limited to the high-placement type microwave oven shown in the first and second embodiments, and may be a movable microwave oven that is not attached to a predetermined position. The present embodiment is applicable to any cooking appliance that admits air inside and discharges air outside. 
     FIG. 20 shows a microwave oven  200  according to the third embodiment of the present invention. Referring to FIG. 20, microwave oven  200  includes a front panel  205  and a door  203  at the front face of a main body  204 . An inlet and an outlet (not shown, corresponding to an inlet  221  and an outlet  222  described afterwards) are provided above front panel  206 . A cover  207  is provided extending over the inlet and the outlet. A control panel  251  through which the user enters a manipulation of microwave oven  200  is provided at front panel  205 . Microwave oven  200  is installed right above a gas range in a cabinet in a kitchen shown in, for example, FIG. 2, likewise the first and second embodiments. 
     FIG. 21 shows microwave oven  200  of the third embodiment with door  203  open. A heat chamber  230  accommodating an object to be heated is provided within main body  204  and behind door  203 . 
     FIG. 22 is a sectional view of microwave oven  200  taken along line XXII-XXII of FIG.  21 . FIG. 23 is a perspective view of microwave oven  200 , with the contour of main body  204  omitted for the sake of describing the interior of microwave oven  200 . 
     Referring to FIGS. 22 and 23, microwave oven  200  includes an intermediate frame  211  and an air channel  212  at the outer side of intermediate frame  211 , both within main body  204 . Intermediate frame  11  is formed to enclose heat chamber  230 , a machine chamber  231  accommodating electronic components for heat control (such as a magnetron  233 ), and an exhaust chamber  232  into which air exhausted from heat chamber  230  is introduced. An outlet  240  is provided at a wall of air channel  212  and at the bottom face of main body  204 . Two hood fans  208  are provided above intermediate frame  211 . Also, inlet  221  and outlets  202  and  222  over which cover  207  extends are provided at the upper portion of front panel  205 . A body guide  210  is provided to guide the air from hood fan  208  exclusively to outlet  202 . 
     When hood fan  208  is actuated in microwave oven  200 , cover  207  attains an open state shown in FIG. 23 from the closed state shown in FIG.  20 . Air is admitted into air channel  212  from inlet  240 , as shown by the open arrow in FIGS. 22 and 23. The air is discharged outside microwave oven  200  from outlet  202  through hood fan  208 . By virtue of the provision of cover  207  at the front of outlet  202 , air can be discharged upwards from outlet  202 . More specifically, cover  207  controls the flowing direction of air discharged from outlet  202  (and outlet  222 ). By the input of air from inlet  240  and output of air from outlet  202  in microwave oven  200 , microwave oven  200  can be used as a ventilator when cooking is carried out by gas range  6 . 
     A partition panel  271  and a knob  272  are provided at cover  207 . Partition panel  271  is provided to avoid the air discharged from outlet  202  from being admitted into microwave oven  200  directly through inlet  221 . Knob  272  is provided to open/close cover  207  manually. The provision of knob  272  allows cover  207  to be opened/closed manually without having to actuate hood fan  208  and fan  234  in the case where the neighborhood of inlet  221  and outlets  202  and  222  is to be cleaned or when the operation of automatically opening/closing cover  207  fails. In the present embodiment, a partition member is implemented by partition panel  271  to prevent mixture of the air admitted into microwave oven  200  through the inlet and the air discharged outside microwave oven  200  via the output when cover  207  is open. Although the partition member of the present embodiment is a panel such as partition panel  271 , any shape is allowed as long as air mixture can be prevented. 
     Referring to FIG. 23,  252  designates an air intake chamber into which air is introduced through inlet  221 . Air intake chamber  252  is connected with machine chamber  232 . Microwave oven  200  includes another fan (fan  234  described afterwards) in addition to hood fan  208  to allow air flow in a manner different from that shown in FIGS. 22 and 23. This different air flow of microwave oven  200  will be described with reference to FIG.  24 . 
     FIG. 24 is a perspective view of microwave oven  200 , likewise FIG. 23 with the outer contour of main body  204  omitted. The different air flow is represented by the open arrow in FIG.  24 . FIG. 24 shows intermediate frame  211  partially broken away to facilitate description of the interior of machine chamber  231 . 
     Microwave oven  200  includes magnetron  233  to heat an object in heat chamber  230  and a fan  234  to cool the components such as magnetron  233  in machine chamber  231 . Upon actuation of fan  234  in microwave oven  200 , cover  207  attains an open state shown in FIG. 23 from the closed state shown in FIG.  20 . Air is admitted into heat chamber  230  from inlet  221  via air intake chamber  252  and machine chamber  231 , as indicated by the open arrow in FIG.  24 . The air passes through exhaust chamber  232  to be discharged outside microwave oven  200  through outlet  222 . 
     Air flows in a different manner by hood fan  208  and fan  234  in microwave oven  200 . Microwave oven  200  has cover  207  automatically attaining an open state as shown in FIG. 23 or  24  when either hood fan  208  or fan  234  functions, as will be described afterwards. When the drive of hood fan  208  and fan  234  stops, cover  207  attains the closed state shown in FIG.  20 . In microwave oven  200 , fan  234  functions automatically when a heating operation is effected by magnetron  233 . Hood fan  208  can be actuated by operating a predetermined key on control panel  251 . In other words, hood fan  208  and fan  234  function independently in microwave oven  200 . 
     The structure of cover  207  will be described with reference to FIGS. 25-28. 
     An arc-like window  276  is formed in partition panel  271 . Microwave oven  200  includes an arm  273  in the proximity of partition wall  271 , and also a stepping motor  274  at the upper portion of the wall forming air intake chamber  252  and at a position corresponding to the back side of inlet  221 . Aim  273  has one end connected to stepping motor  274  and the other end connected to partition wall  271  via a connection member  275  and window  276 . 
     Stepping motor  274  is arranged at a position corresponding to the back side of inlet  221  in order to suppress temperature rise of stepping motor  274 . It is to be noted that inlet  221  is the region where air is introduced in microwave oven  200 . This means that this area is lower in temperature than the other area of microwave oven  200  that encounters temperature rise by the heating operation. By providing stepping motor  274  at a position corresponding to the back side of inlet  221  rather than the position corresponding to the back side of outlet  202  or  222 , increase in temperature of stepping motor  274  can be suppressed. 
     When hood fan  208  or fan  234  is actuated in microwave oven  200 , arm  273  rotates counterclockwise in FIG. 27 about the connecting portion with stepping motor  274  by the drive of stepping motor  274 . As a result, cover  207  attains an open state. FIG. 28 is an enlarged view of the neighborhood of connection member  275  of microwave oven  200  to describe the mechanism of the status change of cover  207 , viewed from the front side. 
     Connection member  275  is attached to arm  273 . Connection member  275  includes a first groove  277  and a second groove  278  at the upper end, and also a lower groove  279  at the lower end. First groove  277  and lower groove  279  have a greater width with respect to the thickness of partition wall  271 . Second groove has a width substantially equal to the thickness of partition wall  271 . When hood fan  208  and fan  234  are not actuated, connection member  275  sandwiches partition panel  271  with first groove  277  and lower groove  279 . Second groove  278  does not sandwich partition panel  271  here. 
     When hood fan  208  or fan  234  is actuated and stepping motor  274  is driven, arm  273  moves upwards, whereby connection member  275  also moves upwards. In response, partition panel  271  is fitted in second groove  278 . Partition panel  271  is displaced according to the operation of arm  273 . In response to a further drive of stepping motor  274 , arm  273  rotates counterclockwise in FIG. 27 about the connecting portion with stepping motor  274 . Accordingly, partition panel  271  rotates counterclockwise about the portion overlapping with stepping motor  274 . As a result, cover  207  attains an open state. When cover  207  returns to the closed state, partition panel  271  is fitted in second groove  278 , and arm  273  is rotated by stepping motor  274  clockwise in FIG. 27 about the connection portion with stepping motor  274 . 
     When hood fan  208  and fan  234  are not actuated, partition panel  271  is not fitted in second groove  278 . Therefore, partition panel  271  can be rotated clockwise or counterclockwise in FIG. 27 without having to rotate arm  273 . Accordingly, cover  207  can be switched between the open/close state manually. In switching cover  207  to the open/close state manually, partition panel  271  is displaced corresponding to first groove  277  and lower groove  279  of the resting connection member  275  in window  276 . 
     Thus, cover  207  can be switched to an open/close state automatically according to the operational status of hood fan  208  and fan  234 . The switching of the open/closed state of cover  7  will be described hereinafter. 
     FIG. 29 is a control block diagram of microwave oven  200 . Microwave oven  200  includes a control unit  300  with a microcomputer to provide overall control of the operation of microwave oven  200 . 
     Control unit  300  is connected to a key input unit  253 , a display unit  254 , magnetron  233 , fan  234 , stepping motor  274  and hood fan  208 . The user inputs information through key input unit  253 . Key input unit  253  is formed of various keys on control panel  251  as shown in FIG.  30 . Display unit  254  is formed of, for example, liquid crystal, and provided on control panel  251  as shown in FIG.  30 . The operational status of microwave oven  200  and input menus and the like are displayed on display unit  254 . Control unit  300  provides control of display unit  254 , magnetron  233 , fan  234 , stepping motor  274 , and hood fan  208  according to the information input through key input unit  253 . 
     The control of switching the open/close state of cover  207  by control unit  300  will be described in detail hereinafter. 
     In microwave oven  200 , the air flow direction of hood fan  208  can be altered by modifying the attached direction of hood fan  208 . The switching of the open/close state of cover  207  differs according to the air flow direction of hood fan  208 . Therefore, altering the air flow direction of hood fan  208  will be described prior to describing the control. 
     Referring to FIGS. 31-33, the positional relationship between the air flow direction of hood fan  208  (open arrow in each drawing) and cover  207  is schematically shown. FIG. 31 corresponds to the case where the air flow of hood fan  208  is directed front of microwave oven  200 , as in the previous description. FIG. 32 corresponds to the case where the air flow is directed backwards of microwave oven  200 . FIG. 33 corresponds to the case where the air flow is directed upwards of microwave oven  200 . 
     Microwave oven  200  is implemented to have the air flow direction of hood fan  208  set to any of the three types shown in FIGS. 31-33. Although not shown, an opening to discharge air outside main body  204  is provided at the area corresponding to the port of hood fan  208  at the upper face and back face of main body  204 . 
     When the air flow of hood fan  208  is directed frontwards of microwave oven  200  as shown in FIG. 31, cover  207  must be opened/closed cooperable with the air flow direction of hood fan  208 . In contrast, the open/closure of cover  207  does not have to be cooperated with the air flow operation of hood fan  208  when the air flow of hood fan  208  is directed in a direction other than the front direction of microwave oven  200 , as in FIGS. 32 and 33. For this purpose, microwave oven  200  includes a fan switch  261  that can sense whether the air flow of hood fan  208  is directed frontwards or in another direction. Detection of whether the air flow direction is frontwards or in another direction is set forth in the following. A switch button  262  is provided at fan switch  261 . Switch button  262  is provided so as to be depressed when hood fan  208  is arranged so that the air flow is directed frontwards, and so as to be not depressed when hood fan  208  is arranged so that the air flow is directed to another direction. Accordingly, the air flow direction can be detected. 
     The contents of the cover open/close process of switching the state of cover  207  by control unit  300  will be described with reference to the flow chart of FIG.  34 . 
     At S 1 , determination is made whether fan switch  261  is ON or not, i.e. whether hood fan  208  is arranged as shown in FIG. 31 with switch button  262  depressed. When determination is made that fan switch  261  is ON (Yes at S 1 ), control proceeds to S 2  to determine whether hood fan  208  is actuating or not. 
     When determination is made that hood fan  208  is during actuation (Yes at S 2 ), control proceeds to S 3 , whereby cover  207  attains an open state. Then, control returns to S 1 . 
     When determination is made that hood fan  208  is not functioning (No at S 2 ), control proceeds to S 4  to determine whether magnetron  233  is operating or not, i.e. whether fan  234  is functioning or not. When determination is made that magnetron  233  is functioning (Yes at S 4 ), control proceeds to S 3 , whereby cover  207  is set to an open state. When determination is made that magnetron  233  is not functioning (No at S 4 ), control proceeds to S 5 , whereby cover  207  is set to a closed state. Then, control returns to S 1 . When determination is made that fan switch  261  is not ON at S 1  (No at S 1 ), control proceeds directly to S 4 . 
     According to the above process, cover  207  is opened and closed when hood fan  208  or fan  234  is functioning and not functioning, respectively, when hood fan  208  is arranged as shown in FIG.  31 . When hood fan  208  is arranged as shown in FIG. 32 or  33 , cover  207  is opened and closed if fan  234  is functioning and not functioning, respectively. 
     In the above embodiment, control unit  300  provides control of the open/close state of cover  207  according to the operational status of hood fan  208  and fan  234  in the process of S 2 -S 5 . By virtue of the execution of the process of S 2 -S 5  in microwave oven  200 , the cover can be opened/closed appropriately irrespective of whether hood fan  8  is functioning according to the heating operation by a heating unit such as magnetron  233  or whether fan  234  is operated independent of the heating operation of the heat unit. 
     In the present embodiment, cover  207  attains a closed state at S 5  when determination is made that magnetron  33  is not functioning at S 4 . This means that cover  7  attains a closed state when the operation of magnetron  33  stops. However, the present embodiment is not limited thereto. Cover  7  may be set to a closed state at an elapse of a predetermined time from the termination of the heating operation. 
     A modification of the present embodiment will be described hereinafter. In the present modification, control unit  300  is made to detect whether the air flow of hood fan  208  is directed frontward or not through the manual operation of a workman or a user through key input unit  253 , absent of fan switch  261 . As an example of input through key input unit  253 , a predetermined key (for example, option key  253   a ) is depressed, whereby a predetermined menu for designating the air flow direction of hood fan  208  is displayed on display unit  253 . A predetermined key can be manipulated therefrom. 
     The contents of the cover open/close process of switching the status of cover  207  by control unit  300  in the present modification will be described hereinafter with reference to the flow chart of FIG.  35 . 
     At S 11 , determination is made whether the air flow direction of hood fan  208  is input (Set) to the forward direction (front exhaust) through key input unit  253 . When determination is made of the setting of front discharge (Yes at S 11 ), control proceeds to S 12  to determine whether hood fan  208  is functioning or not. 
     When determination is made that hood fan  208  is in operation (Yes at S 12 ), control proceeds to S 13 , whereby cover  207  is set to an open state. Then, control returns to S 11 . When determination is made that hood fan  208  is not in operation (No at S 12 ), control proceeds to S 14  to determine whether magnetron  233  is in operation or not. When determination is made that magnetron  233  is in operation (Yes at S 14 ), control proceeds to S 13 , whereby cover  207  is set to an open state. When determination is made that magnetron  233  is not in operation (No at S 14 ), control proceeds to S 15 , whereby cover  207  is set to a closed state. Then, control returns to S 11 . If determination is made that front discharge is not set at S 11  (No at S 11 ), control proceeds directly to S 14 . 
     In the present modification, fan switch  261  is dispensable by providing the function of designating the air flow direction of hood fan  208  by means of key input unit  253 . 
     Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.