Patent Publication Number: US-2004050841-A1

Title: Microwave oven with toaster

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001] This application claims the benefit of Korean Application No. 2002-55991, filed Sep. 14, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates in general to microwave ovens and, more particularly, to a microwave oven with a toaster, which is used to toast bread.  
       [0004] 2. Description of the Related Art  
       [0005] As is well known to those skilled in the art, a microwave oven is an appliance, which cooks food laid in its cooking cavity using microwaves irradiated from a magnetron into the cooking cavity. Typically, an electric heater cooks food by heating surfaces of the food, but the microwave oven cooks food using microwaves generated by oscillation of a magnetron. That is, when microwaves irradiated from the magnetron of the microwave oven cause molecules of moisture laden in food to vibrate, frictional heat is generated within the food and cooks it. Recently, there has been proposed a microwave oven having a heater in the cooking cavity. The microwave oven having the heater allows food to be cooked by heat of the heater as well as microwaves irradiated from the magnetron, thus enhancing a cooking effect of food.  
       [0006] The conventional microwave oven has been widely used to cook a variety of foods due to its convenience. However, the conventional microwave oven has a problem in that it cooks food using microwaves. Therefore, performance of the conventional microwave is inferior to the performance of a typical electric heater when toasting bread.  
       [0007] The conventional microwave oven having the heater in the cooking cavity heats bread using the heat of the heater. However, since the conventional microwave oven is designed such that the heater is installed on an upper portion of the cooking cavity, an additional cooking shelf is inconveniently required to position bread adjacent to the heater. Furthermore, in order to uniformly toast both surfaces of the bread, the bread must be turned over during toasting.  
       SUMMARY OF THE INVENTION  
       [0008] Accordingly, it is an aspect of the present invention to provide a microwave oven with a toaster, which is designed such that the toaster is integrated with a cabinet of the microwave oven to form a single structure without increasing a manufacturing cost of the microwave oven.  
       [0009] Another aspect of the present invention is to provide a microwave oven with a toaster to toast a large quantity of bread.  
       [0010] A further aspect of the present invention is to provide a microwave oven with a toaster, which is easy to put in and take out from a cabinet of the microwave oven.  
       [0011] Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.  
       [0012] The foregoing and/or other aspects of the present invention are achieved by providing a microwave oven with a toaster, including a cabinet provided with a cooking cavity and microwave irradiating unit to irradiate microwaves into the cooking cavity. The microwave oven further includes a toaster body mounted on an upper portion of the cabinet and provided on a front thereof with an opening, a grilling shelf retractably installed in the toaster body to be taken out of the toaster body through the opening and provided with a door to close the opening, a guide unit to guide a movement of the grilling shelf, a drive unit to move the grilling shelf, and a heater unit installed in the toaster body to heat bread laid on the grilling shelf.  
       [0013] According to an aspect of the present invention, the microwave oven also has a toaster casing installed in the toaster body so that an opening of the toaster casing corresponds to the opening of the toaster body, thus closing a gap around the grilling shelf.  
       [0014] According to an aspect of the present invention, the guide unit includes a guide groove longitudinally formed along an inner surface of each sidewall of the toaster casing, and a guide rail longitudinally provided along each sidewall of the grilling shelf to be projected outward from the sidewall of the grilling shelf and to move along an associated guide groove of the toaster casing.  
       [0015] According to another aspect of the present invention, the drive unit includes a rack unit longitudinally provided on the grilling shelf, a pinion unit to engage with the rack unit and rotatably supported on the toaster casing by a rotating shaft, and a drive motor to rotate the rotating shaft of the pinion unit.  
       [0016] According to an aspect of the present invention, the rack unit includes a first rack and a second rack. The first and second racks are longitudinally provided along lower portions of both sidewalls of the grilling shelf, and the pinion unit includes first and second pinions to engage with the first and second racks, respectively. The rotating shaft is rotatably supported at both ends thereof to the toaster casing and is assembled with the first and second pinions to rotate the pinions at the same time.  
       [0017] According to yet another aspect of the present invention, the heater unit includes an upper heater installed on the upper portion of the toaster casing, and a lower heater installed on a lower portion of the toaster casing, such that the heater unit is positioned above and under the grilling shelf.  
       [0018] According to another aspect of the present invention, the toaster casing is open at a bottom thereof to allow crumbs of bread to drop to a bottom of the toaster body, and a crumb collecting tray is installed in the toaster body at a position under the toaster casing to be removable from the toaster body.  
       [0019] According to another aspect of the present invention, a plurality of grilling shelves are installed in the toaster body, and the guide unit, drive unit, and heater unit are installed to each of the grilling shelves.  
       [0020] According to an aspect of the present invention, the grilling shelf includes a grilling part to seat bread thereon, two sidewalls longitudinally extending along both sides of the grilling shelf to support both sides of the grilling part, and a rear wall to connect rear ends of the two sidewalls to each other.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0021] The above and/or other aspects and advantages of the present invention will become apparent and more appreciated from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:  
     [0022]FIG. 1 is a perspective view showing a microwave oven with a toaster, according to an embodiment of the present invention;  
     [0023]FIG. 2 is a perspective view of the toaster installed in the microwave oven of FIG. 1; and  
     [0024]FIG. 3 is a sectional view of the toaster installed in the microwave oven of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0025] Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.  
     [0026] As shown in FIG. 1, the microwave oven according to the present invention includes a cabinet  10 . The cabinet  10  is partitioned into a cooking cavity  11  and a machine room  12 . The cooking cavity  11  is used to cook food. The machine room  12  contains several electrical devices. A door  13  is hinged to a front of the cooking cavity  11  to selectively open or close the cooking cavity  11 . A control panel  14  is mounted to a front surface of the machine room  12 , and is provided with several control buttons to control various functions of the microwave oven.  
     [0027] A cooking tray  15  is rotatably provided on a bottom of the cooking cavity  11  to lay food on the tray  15 . A magnetron and a high-voltage transformer (not shown) are installed in the machine room  12 . The magnetron irradiates microwaves into the cooking cavity  11 . The high-voltage transformer applies high voltage to the magnetron. The above construction allows food laid on the cooking tray  15  provided in the cooking cavity  11  to be cooked by the microwaves irradiated from the magnetron.  
     [0028] A box-shaped toaster body  20  to toast bread is mounted on an upper portion of the cabinet  10 , and is provided on a front thereof with a plurality of openings  21 . A plurality of grilling shelves  30  are retractably installed in the toaster body  20  to be taken out from the toaster body  20  through the corresponding openings  21 . Thus, the toaster body  20  may be integrated with the cabinet  10  to form a single structure. Alternatively, the toaster body  20  may be separately fabricated and then mounted on the upper portion of the cabinet  10 .  
     [0029] As shown in FIGS. 2 and 3, a toaster casing  40 , a drive unit, and a heater unit is installed in the toaster body  20 . The toaster casing  40  surrounds a portion of and closes a gap around each grilling shelf  30 . A guide unit is provided in the toaster body  20  to guide a movement of each grilling shelf  30 . The heater unit heats bread laid on each grilling shelf  30 . The grilling shelves  30  are spaced apart from each other in a horizontal direction. The guide unit, drive unit and the heater unit are installed to each grilling shelf  30 . Thus, only one of the grilling shelves  30  may be used or all of the grilling shelves  30  may be simultaneously used to toast bread.  
     [0030] The toaster casing  40  is open at a front thereof to form an opening  41 . Each grilling shelf  30  is put in and taken out from the toaster casing  40  through the opening  41 . A rectangular opening  42  is formed on a bottom of the toaster casing  40  to allow crumbs to be dropped from the grilling shelf  30  to a bottom of the toaster body  20 . The toaster casing  40  is installed in the toaster body  20  so that the opening  41  of the casing  40  is aligned with the opening  21  of the toaster body  20 .  
     [0031] Each grilling shelf  30  is provided with a door  31 , two sidewalls  32 , a rear wall  33 , and a grilling part  34 . The door  31  has a size corresponding to the opening  21  of the toaster body  20  to selectively open or close the opening  21  when each grilling shelf  30  is taken out from or put in the toaster casing  40 . The two sidewalls  32  longitudinally extend along both sides of the grilling shelf  30 . The rear wall  33  connects rear ends of the two sidewalls  32  to each other. The grilling part  34  is supported at side ends thereof to the sidewalls  32  to seat bread thereon, and includes a plurality of linear bars  34   a  which are spaced apart from each other.  
     [0032] The guide unit to guide a movement of each grilling shelf  30  includes two guide grooves  51  and two guide rails  52 . The two guide grooves  51  are longitudinally formed along inner surfaces of both sidewalls of the toaster casing  40 . The guide rails  52  are longitudinally provided along both sidewalls  32  of the grilling shelf  30  to be projected outward from the sidewalls  32  of the grilling shelf  30 , and move along the guide grooves  51  of the toaster casing  40 .  
     [0033] The drive unit includes first and second racks  61  and  62 , and first and second pinions  63  and  64 . The first and second racks  61  and  62  are longitudinally provided on lower portions of the sidewalls  32  of the grilling shelf  30 . The first and second pinions  63  and  64  engage with the racks  62  and  61 , respectively. The drive unit also has a rotating shaft  65  and a drive motor  66 . The rotating shaft  65  is assembled with the first and second pinions  63  and  64  to rotate the pinions  63  and  64  at the same time. The drive motor  66  is connected to the rotating shaft  65  and rotates the rotating shaft  65 . Thus, the rotating shaft  65  is rotatably supported, at both ends thereof, to sidewalls of the toaster casing  40 . The drive motor  66  is connected to the rotating shaft  65  to be fixed to an outer surface of one of the sidewalls of the toaster casing  40 . The above construction allows the grilling shelf  30  to be automatically taken out from or put in the toaster casing  40  when the two pinions  63  and  64  are rotated by an operation of the drive motor  66  which rotates in alternating directions.  
     [0034] As shown in FIG. 3, the heater unit includes an upper heater  71  and a lower heater  72  to simultaneously heat upper and lower surfaces of bread laid on the grilling part  34  of the grilling shelf  30 . The upper heater  71  is arranged above the grilling shelf  30 , and the lower heater  72  is arranged under the grilling shelf  30 . The upper and lower heaters  71  and  72  are held at upper and lower portions of the toaster casing  40 , respectively, by a plurality of hook members  73 .  
     [0035] As shown in FIGS. 1 and 3, the microwave oven of the present invention also has a crumb collecting tray  80 . The crumb collecting tray  80  is installed in the toaster body  20  at a position under the toaster casing  40 . The crumb collecting tray  80  is fabricated in a form of a drawer to be taken out from the toaster body  20 , so that crumbs collected on the crumb collecting tray  80  through the opening  42  may be emptied as desired. The crumb collecting tray  80  longitudinally extends in a horizontal direction to have an area capable of effectively collecting crumbs dropped from all grilling shelves  30  at one place. Several control buttons  90  are mounted to predetermined positions of a front surface of the toaster body  20  to control an operation of the grilling shelves  30  and the heater unit.  
     [0036] The operation and use of the microwave oven according to the present invention is described below.  
     [0037] When a user desires to cook food through a microwaves-heating method, the food is primarily put in the cooking cavity  11 . Next, the microwave oven is operated. At this time, the magnetron of the microwave oven irradiates microwaves into the cooking cavity  11  to cook the food.  
     [0038] Meanwhile, when the user desires to toast bread, the bread laid on the grilling shelf  30  which is placed in the upper portion of the cabinet  10  is toasted by the upper and lower heaters  71  and  72 . The user first inputs a signal through the control buttons  90  such that the grilling shelf  30  is ejected from the toaster body  20 . Next, the bread is laid on the grilling part  34  of the grilling shelf  30 . Thereafter, the user inputs another signal through the control buttons  90  such that the grilling shelf  30  is retracted into the toaster body  20 . The bread is heated by the upper and lower heaters  71  and  72  for a predetermined period of time.  
     [0039] The two pinions  63  and  64  are rotated in alternating directions by the operation of the drive motor  66  such that the grilling shelf  30  is ejected or retracted into the toaster body  20 . Thus, the bread to be toasted is easily laid on the grilling shelf  30 , while the toasted bread is easily taken out from the grilling shelf  30 . Since the upper and lower surfaces of the bread laid on the grilling shelf  30  are simultaneously heated by the upper and lower heaters  71  and  72 , both surfaces of the bread are uniformly toasted.  
     [0040] The microwave oven of the present invention may be operated with only one of the plurality of grilling shelves  30  selected and used to toast bread. In addition, the microwave oven of the present invention may be operated with all of the grilling shelves  30  used. Thus, the microwave oven of the present invention is convenient to use, and reduces the consumption of energy because only the heater units of the selected grilling shelves  30  are operated.  
     [0041] The crumbs produced during a cooking process drop to the bottom of the toaster casing  40 , through the opening  42  which is formed on the bottom of the toaster casing  40 . The crumbs are deposited on the crumb collecting tray  80 . Thus, the user may periodically take the crumb collecting tray  80  out from the toaster body  20 , and remove the crumbs from the crumb collecting tray  80 .  
     [0042] As apparent from the above description, the present invention provides a microwave oven with a toaster, which is designed such that a toaster body is integrated with a cabinet of the oven to form a single structure, thus achieving a desired function of toasting bread without considerably increasing the manufacturing cost of the microwave oven.  
     [0043] Furthermore, the microwave oven of the present invention allows a large quantity of bread to be simultaneously toasted using a plurality of grilling shelves. The microwave oven of the present invention is designed such that the grilling shelves are ejected from or retracted into the toaster body, thus making it easy to lay bread on the grilling shelves or take the bread out from the grilling shelves.  
     [0044] Although a few preferred embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.