Patent Publication Number: US-3877460-A

Title: Oven door

Description:
United States Patent 1191 Lotz et a1.  
 1451 Apr. 15, 1975 [22] Filed:  
 [ 1 OVEN DOOR [73] Assignee: Whirlpool Corporation, Benton Harbor, Mich.  
 Feb. 1, 1974 21 Appl. No.: 438,864  
 3,267,930 8/1966 Casciani 1261200 3,453,997 7/1969 Kelpzig 3,612,825 10 1971 Chase 126/200 Primary Examiner-John .1. Camby Assistant Examiner-Henry C. Yuen Attorney, Agent, or Firm-Hofgren, Wegner, Allen, Stellman &amp; McCord [57] ABSTRACT A hollow heat insulating door for a cooking oven and the like in which the insulating effect is achieved by a combination of an internal dead air space and an internal heat absorbing black body baffle adjacent to the viewing openings through the door. The disclosure also includes a door for a cooking oven in which aligned inner and outer glass panes are provided for viewing the interior of the oven with one of the panes being semi-opaque with artificial light within the oven shining through but outer natural light being substantially barred when the interior artificial light is absent.  
 19 Claims, 3 Drawing Figures OVEN DOOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to door constructions. and in particular, to insulating door constructions for use with heated compartments such as ovens.  
 2. Description of the Prior Art In the conventional cooking oven construction, a front door is provided to provide selective access to the oven chamber. It is desirable to permit inspection of the interior of the oven such as during the cooking process, and it has been conventional to provide transparent window means in the access door for this purpose. A problem has arisen, however, in that relatively high temperatures of the oven have caused a dangerous high temperature condition of the window means, and a number of different attempts have been made to provide improved insulation of the window means and/or cooling thereof by venting or selectively shielding the window means.  
  In the U.S. Pat. No. of .I. W. Jacobs et al 3,024,074, the door of a domestic appliance, such as a dishwasher is provided with a continuous venting arrangement for permitting exhaustion of steam or vapor from the dishwashing chamber.  
  In U.S. Pat. No. 3,186,401 ofC. M. Mayer et al, a gas range is disclosed wherein the oven is vented at the front of the range.  
  In U.S. Pat. No. 3,267,930 of R. E. Casciani, an oven door is provided wherein an area of decoration is associated with a glass window means thereof.  
  In U.S. Pat. No. 3,362,396 of Bohdan Hurko, the oven door is provided with a removable reflective shield which may be moved into one position obstructing the view through the observation window, or a second position recessed within the door structure.  
  In G. W. Klepzig U.S. Pat. No. 3,453,997, a sump is provided in a flue-like opening, or space, between an insulation retainer and baffle plate in an oven door to provide improved cooling of the door.  
  In F. T. Astrella U.S. Pat. No. 3,489,l35, an oven door window is provided with an outer glass panel spaced from the aperture-defining portions of the frame so that a controlled quantity of air may pass into and through the space between the inner and outer glass panels of the window.  
  In Donald L. Upp U.S. Pat. No. 3,717,138, a sliding shielded window arrangement is provided in an oven door wherein an uninsulated, reflective shield is movable to a blocking position adjacent an outer glass panel to define a large air wash channel for cooling the exposed outer glass panel, a relatively small panel. to provide an air barrier for the door area above the outer glass panel.  
 SUMMARY OF THE INVENTION This invention comprehends a hollow heat insulating door for a heated compartment such as a cooking oven with improved simplified means for inhibiting heat transfer through the door and also comprehends such a compartment wherein an interior artificial light shines through glass panes of the door for viewing the interior of the compartment. at least one of the panes being substantially opaque when the interior light is absent.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of a cooking oven having a door embodying the invention.  
  FIG. 2 is an exploded perspective view of the parts of the door.  
  FIG. 3 is an enlarged vertical sectional view through a door embodying the invention and taken substantially along line 3-3 of FIG. 1.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT The door embodying the invention is illustrated in conjunction with a cooking stove 11 having four surface cooking elements 12 the top one of which is occupied by a pan I3 and all of which are controlled by separate controls 14 at one side of the stove as illustrated in FIG. 1. In this illustrated embodiment the oven 15 is on the bottom of the structure and is provided with its own set of controls all in the customary manner.  
  The door 10 whose parts are shown in exploded perspective view in FIG. 2 and in assembled vertical section in FIG. 3 is heat insulating and therefore acts as a heat barrier between the interior of the oven 15 which is on the right-hand side of FIG. 3 and the exterior of the door which is on the opposite side of FIG. 3. As illustrated, the door comprises a peripherally closed frame 16 comprising an outer marginal wall 17 and spaced apart inner l8 and outer l9 panels with these panels having aligned viewing openings 20 and 21, respectively.  
  The outer viewing opening 21 is considerably larger than the inner opening 20 and each is provided with an inner glass pane 22 and an outer glass pane 23 with the inner pane being correspondingly smaller than the outer pane. Means are provided for locating each pane with respect to its panel with the locating means for the inner pane 22 comprising sealing means in the form of a distortable silicone rubber gasket 24 attached to the inner panel 18 at a flange 25 defining the viewing opening 20 and an edge distortable foot 26 pressing against the inner surface 27 of the inner pane 22.  
  The outer glass pane 23 is located with respect to the outer panel 19 by a plurality of silicone rubber bumper or cushion members 28 which in this instance are of L- shaped cross section to embrace the outer edge and the inner surface adjacent this edge as shown in FIG. 3. The pane 23 and the bumpers 28 are held in position by four sheet metal glass clamps 29 each located at a corner of the panel 19 and pane 23 with each clamp 29 held in position by a pair of screws 30 engaging the panel 19 of which only one each of two corner pairs are illustrated in FIG. 3.  
  The combination of the panes and panels provides an interior dead air space that results in conduction heat insulation from the interior of the oven 15 to the front 31 of the oven adjacent to the outer glass pane 23 in the outer panel 19. To provide additional heat insulation there is also provided a heat absorbing baffle 32 which is a black body&#34; for absorbing heat and which in this embodiment is sheet metal having a coating on both sides of black oxide. The baffle 32 is of generally inverted U-shape as illustrated in FIG. 2 with spaced sides 33 that define the sides of the inner viewing opening 20 with these spaced sides 33 being provided with outwardly turned bottom flanges 34 that are horizontally aligned to serve as a bottom support for the bottom edge of the inner pane 22 as illustrated in FIG. 3.  
  The outer glass pane 23 is semi-opaque. The outer glass pane 23 may advantageously have a transparent viewing area 23a, and an opaque border area 2312 covered by ceramic paint, with the viewing area 23a having crossing opaque lines of ceramic paint applied to the glass in a screen pattern. The viewing area 23a is capable of passing artificial light so that an interior illumina tion in the oven will shine through so that the interior can be viewed during cooking when the interior electric light (not shown) is on but will substantially bar exterior and particularly natural light when the interior of the oven is not illuminated.  
  The bottom of the marginal wall 17 is attached to the inner panel 18 by a plurality of screws 35. The inner panel 18 at the top and sides is attached to corresponding portions of the frame 16 by a plurality of screws 36 that extend through the inner panel 18 and engage a flange 37 that is integral with the frame 16.  
  As is shown most clearly in the exploded view of FIG. 2 the method of assembly is as follows. The outer extruded frame 16 and outer glass pane or panel 23 are assembled together with the corner clamps 29, four pairs of corner screws 30 and glass edge bumpers 28. Then a customary hinge frame 38 with lower side hinge members 39 is positioned on the above frame and glass pane subassembly and then the heat absorbing baffle 32 is positioned against the hinge frame 38 as shown in FIG. 3. Then the inner glass pane 22 is positioned as shown in FIG. 3 with the bottom being held by previously described aligned flanges 34 and the vertical edges of the pane 22 being held by the pair of side clamps 40 with these clamps being held in position by two sets of three screws 41 that are driven through the glass clamps 40 and the baffle sides 33 and the hinge frame 38 where they are retained in the hinge frame 38.  
  The inner door panel 18 with the seal 24 in place on the flange 25 as shown in FIG. 3 is positioned over the previously assembled parts and joined to the frame 16 by the screws 35 and 36.  
  As can be seen from the above description, the heat insulated door of this invention is light in weight and inexpensive to build yet has high heat insulating value due to the provision of the interior dead air space, the black body heat insulating panel and the outer pane 23. In addition, there are few paths of direct heat transfer from the interior of the oven to the exterior as the inner panel 18 is out of direct contact with the frame I6 except for eight attaching screws 35 and 36. The door may be used in built-in ovens, set-in ranges including glass cooktop versions and similar heated cabinets. The door is attractive, inexpensive and is sufficiently cool to meet the severe requirements for listing by Underwriters Laboratories, Inc. (UL). UL requires that the viewing area of the door be not more than 90 F. above room ambient temperature, the frame I6 be not more than l F. above this ambient, and that the other external portions of the oven door he not more than 75 F. above this room ambient.  
  With the door of this invention there is no need for cooling air circulation through the door as was required in many prior doors and there are very few areas of direct heat transfer through the door.  
 We claim:  
  1. A hollow heat insulating door for a cooking oven, comprising: a peripheral closed frame comprising a marginal wall and spaced apart inner and outer panels having aligned viewing openings, the opening in said outer panel being vertically substantially larger than the opening in the inner panel; an inner glass pane on the inner panel spanning the inner viewing opening; an outer glass pane on the outer panel spanning the outer viewing opening; means sealing said inner glass pane to its said panel, said panels and panes providing an interior insulating substantially dead air space; and a heat absorbing baffle in said dead air space for limiting heat transfer through the door. said baffle having an upper portion spaced outwardly of said inner panel above said inner glass pane and spaced inwardly of the upper portion of the outer glass pane and defining an opening providing&#39;unimpeded viewing of the oven through said aligned panel viewing openings.  
  2. The door of claim 1 wherein said outer glass pane is semi-opaque with interior artificial light shining therethrough but outer natural light being substantially barred.  
  3. The door of claim I wherein said heat absorbing baffle comprises a black coated steel sheet.  
  4. The door of claim 3 wherein said heat absorbing baffle comprises a black oxide coated steel sheet.  
 5. The door of claim 1 wherein said outer panel is of narrow width about its opening compared to the width,  
 of said inner panel about its opening.  
  6. The door of claim 5 wherein said inner glass pane is of considerably smaller area than said outer glass pane.  
  7. The door of claim I wherein each said panel is provided with resilient means locating each panel with respect to its glass pane adjacent to said inner and outer openings.  
  8. The door of claim 1 wherein said heat absorbing baffle comprises side portions and a top portion having inner edges substantially coextensive with the corresponding outer edges of the sides and top of said inner glass pane and has a projecting flange underlying and supporting the bottom of said inner glass pane.  
  9. A hollow heat insulating door for a cooking oven. comprising: a peripheral closed frame comprising a marginal wall and spaced apart inner and outer panels having aligned viewing openings, the opening in said outer panel being vertically substantially larger than the opening in the inner panel; an inner glass pane on the inner panel spanning the inner viewing opening; an outer glass pane on the outer panel spanning the outer viewing opening, said outer pane being substantially larger than said inner pane and being semi-opaque with interior artificial light shining therethrough but outer natural light being substantially barred; means sealing one of said panes to its said panel, said panels and panes providing an interior insulating dead air space; and a heat absorbing baffle in said dead air space for limiting heat transfer through the door, said heat absorbing baffle comprising a black coated steel sheet having an upper portion spaced outwardly of said inner panel above said inner glass pane and spaced inwardly of the upper portion of the outer glass pane and defining an opening providing unimpeded viewing of the oven through said aligned panel viewing openings.  
  10. The door of claim 8 wherein said outer panel is of narrow width about its opening compared to the width of said inner panel about its opening, said inner glass pane is of considerably smaller extent than said outer glass pane and with resilient means sealing one of said panel and glass panes to the frame to provide an interior insulating substantially dead air space; and means for reducing heat flow from the inner panel to the outer pane through said space comprising a black heat absorbing thermally conductive baffle interposed between preselected portions of said inner panel and said outer pane.  
  13. The door of claim 12 wherein said heat absorbing baffle comprises a black coated steel sheet.  
  14. The door of claim 12 wherein said heat absorbing baffle comprises a black oxide coated sheet.  
  15. The door of claim 12 wherein said heat absorbing baffle comprises a black oxide coated steel sheet.  
  16. A hollow heat insulating door for a cooking oven, comprising: a peripheral closed frame comprising a marginal wall and spaced apart inner and outer panels having aligned viewing openings; an inner glass pane on the inner panel spanning the inner viewing opening; an outer glass pane on the outer panel spanning the outer viewing opening; means sealing said inner glass pane to its said panel. said panels and panes providing an interior insulating substantially dead air space; and a black heat absorbing baffle interposed between preselected portions of said inner panel and said outer pane for limiting heat transfer through the door.  
  17. The door of claim 16 wherein said heat absorbing baffle comprises a black coated steel sheet.  
  18. The door of claim 16 wherein said heat absorbing baffle comprises a black oxide coated sheet.  
 19. The door of claim 16 wherein said heat absorbing baffle comprises a black oxide coated steel sheet.