MICROWAVE OVEN WITH COMMON WRAP AND CAVITY WALLS

Abstract: A low-cost microwave oven construction wherein a single sheet of metal forms both the cooking cavity and the outer wrap. The cavity, components compartment (12), and front and back panels (16, 17) are joined by a continuous crimped seam to form a unitary oven construction.

Description: MICROWAVE CIVEN WITH COMMON WRAP AND OMriTY W Bac1ground of the Invention This invention relates to the construction of microwave ovens, and especially to the construction of the oven cavity and outer wrap. Because of the need to contain microwave frequency energy in a controlled fashion, almost all microwave ovens heretofore knows include a discrete, box-like element referred to as the cooking cavity, or simply cavity. The cavity was secured into some kind of frame which housed the remainder of the oven operating components, the entire assembly being enclosed in a decorative outer shell, called a wrap. Because of keen competition in the marketplace, it is necessary that microwave ovens be constructed as economically as possible. One way to realize substantial manufacturing economy is to combine the oven cavity and outer wrap into a single element. The present invention teaches how such a combination may be accooplished, which combined with other aspects of the invention provide a truly economical construction. Summary of the Invention The present ineention provides for the construction of a microwave oven having a combined oven cavity and wrap. A single formed metal sheet is folded to form an oven cavity which simultaneously provides one side wall and a major portion of the top and bottan walls of the outer wrap. A component section is added to the cavity to complete the other side wall and the remaining portion of the top and bottam of the wrap. A front and back panel are added to complete the construction. The cavity portion as well as the front and back panels may all be assembled by crimping techniques, thereby eliminating the need for welding or other forms of fastening. Brief Description of the Drawings In the drawings, Figure 1 is an exploded perspective view showing the microwave oven construction of the present invention. Figure 2 is a perspective view of the assembled oven. Figure 3 is an enlarged partial cross section taken at line 3-3 of Figure 2 showing a portion of the crimp seam. Figure 4 is an enlarged cross section of the crimp seam shown in Figure 3. Description of Preferred Embodiments Referring to the drawings, the oven cavity 10 is formed fran a single flat metal sheet which has been formed and folded to construct a generally box-like cavity. Hence the cavity 10 includes top wall 20, side wall 21, bottom wall 22 and side wall portions 23 and 24 each having flanges 18 and 19. After folding, side wall portions 23 and 24 are joined together along edge 26 by means of a crimp seam whereby the side wall portions are folded upon one another to form a secure folded seam of the type illustrated in Figures 3 and 4. An aperture 25 is provided in the side wall 24, over which is mounted a wewepILd 15. A components compartment 12 consisting of a generally U-shaped metal sheet having an access portion and flanges 13 and 14 is attached to the cavity element 10 by spotwelding along the flanges 13 and 14. Back panel 17 and front panel 16 are now added to the cavity/ component compartment assembly. Ihe front panel 16 is initially spotwelded to the flanges 18. The back panel 17 is initially spotwelded to the flanges 19. A crimp seam is then formed about the entire periphery of front panel 16 and back panel 17 crimping the front and back panels to the cavity element 10 and the component compartment 12. After the crimping operation the microwave oven structure is shown in Figure 2 results. The details of the crimp seam are shown in Figures 3 and 4. After the electronic and other operating components of the microwave oven have been assembled in component coniparment 12, an access panel (not shown) is placed over the component compartment 12 to close it. The access panel may be attached by means of tamper-proof fasteners. A microwave oven door (not shown) is then mounted to a front panel 16 to complete the oven construction. The metal sheet from which the cavity element 10 is formed can be finished and decorated as desired. whence the exterior side of top wall 20 and side wall 21 may be paInted some chosen color or may be covered with woodgrain vinyl. The interior side of the same top wall 20 and side wall 21, as well as bottom wall 22 may all be painted a different color, such as white, for the interior of the oven cavity. However it is important to note that the oven cavity and outer wrap are both provided by the same single metal sheet and that there is no separate cavity and/or outer wrap portion. The exterior of component com- parament 12 will of course be finished in the same manner as the exterior portion of the cavity element 10. The construction described and illustrated provides for an extremely simple microwave oven construction comprising a very small number of individual parts. The use of the common cavity wall and outer wrap reduces the materials used in the oven and the construction complexity to a minimum, and the use of crimping techniques to assemble the components greatly reduces the labor required in assembly as comer pared to previously Imown constructions.

Claims: CLAIMS 1. A combined microwave oven cavity and wrap comprising: (a) a first formed metal sheet folded into an open-ended box-like cavity; (b) a second formed metal sheet attached to one side wall of said cavity to form a components compartement; (c) a first panel extending substantially across both said cavity and said components compartment forming an oven front, and, (d) a second panel extending substantially across both said cavity and said components compartment forming an oven back; (e) said first and second panels being joined to said cavity and said components compartment along a continuous crisped seam to form a unitary assembly; whereby said first formed metal sheet forms both the cavity interior walls and portions of the outer oven wrap. 2. The structure of claim 1 wherein the ends of said first formed metal sheet are joined along a crimped seam.

Inventors: MILLMAN, RONALD W.
Applicants: LITTON SYSTEMS, INC.
Application year: 1983
Main classification: H05B6
IPC codes: H05B6