US3507266A - Oven door with door sealing gasket - Google Patents

Description

April 21, 1970 L A. voNAscH OVEN DOOR WITH DOOR SEALING GASKET- Hxs ATTORME# April 21, 1970 A. voNAscH 3,507,266

OVEN DOOR WITH DOOR SEALING GASKET Y Filed Oct. 18, 1968 2 Sheets-Shea?l 2 lo@ 9o INVENTOR 7 LOLHS A. VONASCH f BY 4 45 3g \79 MKM H 5 ATTORNEY United States Patent O U.S. Cl. 126-190 5 Claims ABSTRACT OF THE DISCLOSURE The present invention relates generally to cooking ovens and other heated cavities and particularly to the construction of an access door with a door sealing gasket extending around the periphery of an inner panel of the door such that expansion or distortion of various parts of the door due to the exposure of the door to high temperatures cannot disturb or break the sealing contact of the gasket with the front portion of the oven. The oven door is a sheet metal door that is generally hollow and loaded with thermal insulating material so as to retard the heat flow through the door. It is important to substantially seal the oven so as to restrict the loss of heat around the door. This restriction of the heat loss is accomplished by a high temperature gasket that is fastened to the periphery of an inner panel of the door. The gasket is of Woven tubular construction of ber glass or the like material which is rst attened into a belt shape. One longitudinal edge portion of the gasket is positioned on the outside surface of a peripheral flange of the inner panel and conned there by a retaining means. The gasket is then folded over the retaining means and around the edge of the peripheral flange and over the surface of the flange. The other longitudinal edge of the gasket is provided with a tension member in the form of a draw string or wire-like member. This tension member is pulled tightly and its two ends are each tied down by being wound around a separate support bracket carried on the inside of the inner panel and this serves to stretch the gaskettransversely of itself so that it cannot become wrinkled. The inner panel is furnished with three of these support brackets, two adjacent the bottom corners thereof, and one at the top centered between the other two. This gives a three point support system for the inner panel to the main door assembly such that expansion or distortion in the other parts of the door cannot disturb or break the gasket seal contact with the front ange of the oven liner. There is a heat shield baille Within the door which separates the thermal insulation and provides a cooling air channel extending from the bottom to the top of the door for a natural draft of room air therethrough.

CROSS-REFERENCE TO RELATED PATENTS The present invention has been adopted for the use with a self-cleaning oven that `follows the general teachings of the basic patent of Bohdan Hurko No. 3,121,158 which explains the controlled use of heat for automatically removing the food soils lodged on the inner walls forming an oven cooking cavity, where the cleaning cycle has a maxmum oven wall temperature somewhere between about 750 F. and about 950 F. for a suicient period of time for degrading the food soils into gaseous products which are then treated by an oxidation unit or smoke eliminator which oxidizes the gases before they are returned to the kitchen atmosphere. Hurko utilized an oven door sealing system which is supported from the front of the oven body, while in the present invention the door sealing system is carried by the door.

Another related patent is that of Clarence Getman No. 3,189,020 which also pertains to an oven door for use with a high temperature heated cavity such as a selfcleaning oven, and it has a door gasket carried by the door as well as a floating inner panel of the door forming one wall of the heated cavity so as to allow the inner panel to expand freely and prevent the setting up of excessive thermal and mechanical stresses due to differences in the rate of expansion between the door proper and its inner panel.

BACKGROUND OF THE INVENTION This invention was conceived during the development of an improved oven door for a high temperature selfcleaning oven, although the invention is of general utility and could be adopted for use with any similar high 4temperature heated cavity. In a self-cleaning oven, the soiled interior oven walls are cleaned automatically by using a high temperature heat cleaning cycle. A major annoyance in using an oven is the difficulty encountered in keeping the walls of the oven liner and inner panel of the door clean. During the normal cooking operations, food particles and grease spatterings often form on the hot walls forming the cooking cavity where they are partially burned in place and hence adhere tenaciously thereto. Strong cleaning agents have been devised for application to the oven walls for the express purpose of easing the task of removing food soil from them. However, even the best of these cleaning agents requires a strong rubbing action t0 loosen the soil and they comprise strong chemical agents which must be handled with care so as to avoid injury to the skin, eyes and clothing. Such a high temperature self-cleaning oven is described and claimed in the abovementioned Hurko patent, which is assigned to the same assignee as is the present invention.

The oven door of the present invention is of generally hollow sheet metal construction which is for-med with an inner panel on its inner side that is adapted to protrude into the front opening of the oven liner in the manner of a plug. The inner panel includes a peripheral flange on which is mounted the thermal gasketing system of the present invention. Moreover, the inner panel is supported on the door proper by a three point support system such that expansion or distortion of the door due to 'thermal stresses cannot disturb or break the seal contact with the front of the oven liner.

The principal object of the present invention is to provide a door for a high temperature heated cavity with a door sealing gasketing system which is at and without `wrinkles and maintains its integrity when the oven door is exposed to high temperature.

A Ifurther object of the present invention is to provide an oven door with a door sealing gasket of thermal insulating material which may be stretched into place so as to eliminate any possibility of the gasket Wrinkling and thereby preventing the door from closing properly.

SUMMARY OF THE INVENTION The present invention, in accordance with one form thereof, relates to a door for a high temperature heated cavity such as a self-cleaning oven. The door has an inner panel supported on its innermost side by a series of widely spaced fastening means of low heat conduction. The inner panel has a peripheral ange adapted to be located closely parallel to the inner side of the door. A door sealing gasket of thermal strip material surrounds the peripheral ange. Retaining means overlies one longitudinal edge of the gasket. The gasket s folded over the retaining means and around the other side of the flange. A second longitudinal edge of the gasket incorporates a flexible tension member which when placed under tension serves to stretch the gasket material transversely of itself.

3 BRIEF DESCRIPTION OF THE DRAWINGS My invention will be better understood 4from the following description taken in conjunction with the accompanying drawings and its scope will be pointed out in the appended claims.

FIGURE 1 is a left, side elevational view of a freestanding electric range equipped with an oven door embodying the present invention with parts broken away to show the front of the oven liner and its cooperation with the door sealing gasket mounted on the door.

FIGURE 2 is a cross-sectional elevational view of an enlarged scale taken through the vertical center of the oven door of FIGURE 1 and showing the hollow nature of the door and the manner in which the thermal insulation is supported within the door, and particularly the nature of the inner panel supported on the innermost side of the door and carrying on its peripheral liange the gasket system of the present invention.

FIGURE 3 is a fragmentary, cross-sectional elevational exploded view of the top portion of the door of FIG- URE 2 with the parts disassembled so as to best show their respective configurations.

FIGURE 4 is a detailed elevational view on an enlarged scale of the innermost side of the oven door of FIGURE l showing the door gasket extending around the periphery of the inner panel and having parts broken away and others in dotted lines to show the retaining means for the gasket, the heat shield baie for forming an air channel in the front portion of the door, and the manner of supporting the inner door liner from the outer door panel as well as supporting the inner panel from the inner door liner.

FIGURE 5 is a, fragmentary detail view of one of the retaining strips for the gasket embodying the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to a consideration of the drawings and in particular to FIGURE l there is shown for illustrative purposes a free-standing electric range having a top cooling surface 11 with a plurality of surface heating elements 12, an oven cavity 13, a front-opening drop-door 14 for the oven, and a backsplash 15 arranged along the back edge of the cooking surface 11 and containing a control panel in the front face thereof which includes a plurality of manually settable control devices 16 which govern the energization of the various heating elements of the range. The oven cavity 13 is formed by a boxlike oven liner 18 that has an open front that is adapted to be closed by the oven door 14 that was mentioned previously. As in standard electric ovens, there is a lower heating element or bake unit 20 and an upper heating element or fbroil unit 21. Both the ibake and broil units 20 and y21 respectively are provided with electrical terminals that extend out through the back wall of the oven liner for connection to lead wires (not shown) in the power circuit of the oven, as is standard in this art. The oven liner 18 is insulated from the range body 10 by having a relatively thick blanket of fiber glass insulation 24 completely surrounding the oven liner in order to prevent or reduce the dissipation of heat energy from the oven cavity, as well as to maintain the temperature of the outer walls of the range 10 at a safe temperature below a maximum of about 194 F. which is a requirement of the Underwriters Laboratories Inc. for the side wall panels of a free-standing range. Another way of restricting the temperature of the walls of the range body 10 is to include a forced Ventilating system (not shown) for circulating room air between the insulated oven liner and the outer walls of the range body.

It is important to be able to restrict the loss of heat in the vicinity of the oven door 14 thereby making it possible to maintain uniform, internal oven wall temperatures and thereby obtain a one hundred percent selfcleaning action which requires no hand scrubbing. Several steps have 'been taken in order to accomplish this objective, and the first one is to thermally isolate the oven liner 18 from the range body 10. The front of the oven liner 18 is provided with an outwardly turned flange 26, as is seen in FIGURE 1, which is adapted to cooperate with an inwardly tapered ange 28 of the front of the range body which defines a front opening through which the oven liner 18 is assembled into the range body. The oven liner is held in place by applying a tension force to the back of the oven liner with adjustable tension springs or the like as at 30 so that the peripheral ange 26 at the front edge of the oven liner will be pulled back and held against the flange 28 of the door frame of the range body.

Moreover, a third heating element 32 referred to as a mullion heater is sandwiched between the front ange 26 of the oven liner and the tapered llange 28 of the range body so as to compensate for the heat loss in the vicinity of the door opening and thereby hold generally uniform wall temperatures throughout the oven cavity, and especially along the front of the bottom wall, and in the two front corners of the oven liner.

As is best seen in FIGURES 1 and 2, the oven door 14 is of hollowsheet metal construction having three main elements, an outer door panel 35, an inner door liner 36 and an inner panel 37 which is adapted to protrude into the mouth of the oven liner in the manner of a plug. The outer door panel 35 is of shallow pan-shape by virtue of the fact that it has a rearwardly turned peripheral flange 39. The inner door liner 36 is also of shallow pan-shape, and it is of mating construction with the outer door panel by virtue of the fact that it has a front-turned peripheral flange 41 which telescopes within the flange 39 of the outer door panel 35. The inner door liner 36 includes a generally rectangular, central, outer embossment 43 of a size slightly less than the size of the front opening of the oven liner 18, and also slightly less than the size of the inner panel 37.

Next will be discussed the method of fastening the inner door liner 36 to the outer door panel 35 with reference to FIGURES 2, 3 and 4 of the drawings. Looking rst at FIGURE 2, the lower edge of the flange 39 in the outer door panel is provided with two or more upwardly lanced tabs 45. A mating opening 47 is formed for each tab in the lower edge of the flange 41 of the inner door liner, as is more or less standard construction in the oven door art so that the lower edge of the flange 41 may be placed over the lower edge of the flange 39 with the tabs 45 extending through the openings 47 thereby fastening together the lower edge of the outer door panel with the inner door liner.

t The upper edges of the outer Vdoor panel 35 and the inner door 36 are fastened together by using two door handle support brackets 49, as is best seen in FIGURE 3. Each bracket 49 is of inverted channel shape having an elongated front 'leg 50 bearing against the inner side of the outer door panel, a horizontal bight or connecting portion 51 and a shortened leg 52 that Iis adapted to engage the inner side of the inner door liner 36. An oven door handle 54 as best seen -in FIGUR-E 2 has a hand-engaging portion 455 which extends :horizontally for nearly the complete width of the door and a strap portion 56 at each end of the portion 55 fastened to the outer side of the outer door panel 35. A suitable screw opening (not shown) is formed in the front leg 50 of the door handle support bracket 49 as well as through the outer door panel. Each strap 56 of the handle includes a. threaded opening so that -a fastening screw 58 may be inserted from the interior of the outer door panel through the two openings in the leg 50 and the outer door panel for threaded engagement in the strap 56 of the door handle. The short leg 52 of the door handle support bracket 49 also has a screw opening 60, `and the inner door liner has a similar opening I61 which may be aligned with the opening 60 so that a sheet metal screw 62 may be inser-ted through the inner door liner and threaded into the opening 60 of the door handle support bracket 49. Notice the screw 62 is -visible on the innermost side of the door, as is seen in FIGURE 4. Also the left side of the innermost surface of the door in FIGURE 4 is broken -away to show the door handle support bracket 49 closely spaced adjacent the upper corner of the door.

From the showings in FIGURES 2 and 4, the interior side of the inner door liner 36 is provided with a pair of channel-shaped reinforcements 65, where each channel member is positioned with its two ends located adjacent the peripheral edge of the inner door liner 36 and its center section spanning the lower corner of the embossment 43, as is best seen in FIGURE 4. These two channel members 65 are symmetrically arranged with its lower end adjacent the center of the bottom edge of the door and its upper end adjacent a point slightly below the top corner of the door. The two channel members 65 when viewed together appear as upwardly diverging or in the shape of a large V. A layer of thermal insulation 67 of fiber glass or the like is packed into the interior of the embossment 43 of the inner door liner and is held in place by the two channel members 65. A second insulating layer 68 fills the remainder of the inner door liner. A heat shield baille 70 of aluminized steel or the like is positioned within the outer door panel 35 as is best seen in FIGURE 2. This baffle 70 is provided with a series of lanced tabs or spacers 72 on its front face which tend to space the baille from the outer door panel and create a vertical air channel 75 in place. On the rear side of the heat baille 70 is a series of folded-over flange portions 74 generally on the peripheral edge thereof for engagement with a second thickness of thermal insulation 68 within the inner door liner. The vertical air channel 75 formed in the interior of the oven door 14 toward the front thereof, has slotted, air inlet openings 79 formed in the lower edge of the flange 39 of the outer door panel 35 for nearly the complete width of the door, and slotted air outlet openings '82 in the top edge of the flange 39 of the outer door panel so as to create a tall chimney effect and cause a natural draft of room air to flow continuously into the bottom and out of the top of the door during the operation of the oven.

'This ybrings us to a consideration of the inner panel 37 which is likewise of shallow pan-shape having a frontturned peripheral flange 76 and an outwardly turned peripheral flange 77 which is adapted to overlie a rear surface of the inner door liner 36 slightly larger than the outer embossment 43. Notice that the distal edge 78 of the peripheral flange 77 is formed with a rolled-over lip 78 which extends completely around the inner panel to give the flange 77 a reinforcing structural edge.

There is a three point support system for supporting the inner panel 37 over the embossment 43 of the inner door liner 36. 'Ihe locations of the three points are best seen in FIGURE 4 as a series of three support brackets 80', where two brackets are located along the bottom edge of the flange 76 and one bracket is located along the top edge of the flange 76. The two bottom brackets 80 are symmetrically arranged on either side of the vertical center line of the door adjacent the corners of the door while the single top bracket 80 is located on the vertical center line of the door to give an equilateral triangular shape when a line is drawn joining the centers of the three brackets. Turning back to FIGURE 2, each support bracket is of thin strip `material which in side view has an angular supporting foot 81 which is adapted to be welded or otherwise fastened to the inner side of the flange 76 of the inner panel. This angular foot 81 is shown as formed at an acute angle of about 45. Connected to the supporting foot 81 is a right angular portion 83 which is the fastening portion and includes a screw opening 84 for receiving a fastening screw I85. A similar screw opening 86 is formed in the embossment 43 of the inner door liner for alignment with the screw opening 84 in the support bracket. Notice at the top portion of FIGURE 2 that the screw opening 86 for the top support bracket 80 is elongated in a vertical direction to allow for the expansion and contraction of the various elements of the door without exerting an unduly large stress or strain on the inner panel 37 which might otherwise cause the porcelain finish on the innermost side of the inner panel to craze or crack due to thermal or mechanical shock. A layer of insulating material 89 fills the inner panel 37.

The peripheral flange 77 of the inner panel extends completely around the inner panel and has a rectangular configuration as is best seen in FIGURE 4. A gasket 90 of high temperature resistant material such as woven fiber glass or the like is adapted to be assembled over the peripheral flange 77. In the preferred embodiment, the gasket 90 is woven as a hollow sleeve and then flattened into a flat belt of double thickness. One longitudinal edge 92 of the gasket is fastened to the rearmost side of the peripheral flange 77 by means of a plurality of retaining members 94 which are in narrow thin strip sheet metal form having lanced tabs 95 as is seen in FIGURE 5, which are adapted to pierce the double thickness of gasket material and extend through a suitable hole 9-7 in the peripheral flange 77, as seen in FIGURE 4, after which the tabs are bent or folded over against the frontmost side of the inner panels as is best seen in FIG- URE 3. These retaining members 94 extend for nearly the entire extent of the peripheral flange 77. There are special corner retaining members 93 and long sections 100 at the top and bottom of the door, and shortened sections 99 at the two sides of the door thereby extending for nearly the complete width thereof.

The fiber glass gasket 90 is woven of a long length of many yards of tubular or sleeve, and it is flattened and wound upon a reel. When the gasket is to be applied to the door, it is cut off to the desired length and fastened to the flange 77 by the plurality of retaining members 94, such as section 93, 99 and 100. The two ends of the gasket are brought together at the center of the bottom edge of the door as at 102 shown in FIGURE 4. After the first longitudinal edge 92 of the gasket is held down by the retaining means 94, the gasket 90 is folded back over the retaining members as at 108 and then stretched around the outside of the peripheral flange and across the frontmost face of the peripheral flange 77 as at 110.

Notice in FIGURE 3 that the second longitudinal edge 112 of the gasket 90 is provided with a tension member in the form of a flexible wire or draw-string k1'13 which extends for the complete length of the gasket 90. Hence, when the two ends 102 of the gasket are brought together in a butt joint, as is seen in FIGURE 4 the two ends of the wire 113 may be pulled tight and then wound around and anchored on the opposite support bracket 80u This tensioning of the gasket serves to stretch the gasket tightly around the peripheral flange 77 so as to prevent the gasket from becoming wrinkled and thereby break the seal of the gasket with the front flange 26 of the oven liner 18.

In order to fasten these two butt ends of the gasket together, a closure clip 104 of high temperature resistant material such as nickel alloy is fashioned of generally U-shape in transverse cross-section to straddle the two `gasket ends and slip over the flange 77, as is best seen at the lower portion of FIGURE 2. This clip |104 is held in place by use of a pair of screw fastener members 106 which are inserted through suitable openings 107 in the closure strip and pierce the gasket and then through a suitable opening in the peripheral flange 77 and then again to pierce the gasket and to thread into an opening 108 in the back side of the clip 104.

Looking at FIGURE 4, attention is directed to an indentation which is formed along the bottom of the door in the inner door liner 36 in the vicinity of the bottom edge of the peripheral flange 77 of the inner panel 7 37. This indentation 115 extends slightly around the two lower corners of the inner panel. The ange 77 of the inner panel 37 is also indented to coincide with the indentation 115. The purpose of these indentations or setback is to provide a controlled air intake opening for both the baking and the cleaning modes of the oven. This indentation spaces the gasket 90 away from the oven ange 26 across the bottom and the two lower corners of the inner door liner. Thus the gasket in the lower two corners of the bottom section is held in a plane parallel to the plane of the rest of the gasket providing in essence a narrow, rectangular air intake opening. Another advantage of this is that this recessed design practically eliminates sliding contact of the lower portion of the gasket with the front flange of the oven liner when the door is either opened or closed due to the hinging action of the door.

Modifications of this invention will occur to those skilled in this art. Therefore, it is to be understood that this invention is not limited to the particular embodiments but that it is intended to cover all modifications which are within the true spirit and scope of this invention as claimed.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A door construction for a high temperature domestic oven having an insulated oven cavity formed by a boxlike oven liner and a front-opening access door, the door design having an outer door panel, an inner door liner, and an inner panel all fastened together, thermal insulation interposed between the outer door panel and the inner door liner and between the inner door liner and the inner panel, the inner panel being of shallow pan shape that is adapted to protrude into the mouth of the oven cavity, the periphery of the inner panel having an outwardly turned `fiange, a strip of thermal gasket material folded over the said flange and held into engagement with the inner door liner as well as being adapted to engage the front face of the oven liner and sealed therewith when the door is closed, retaining means on the outside of the inner panel for holding one longitudinal edge of the gasket on the flange, and a flexible tension member extending the length of the gasket at the other longitudinal edge on the inside of the inner panei, and means for holding the tension member in stretched condition while reducing its effective length so as to tighten the gasket over the flange.

2. A door construction as recited in claim 1 wherein the said gasket is a flexible sleeve member that is fashioned into a wide belt-like member, the retaining means for the gasket being located on the outside of the iiange of the inner panel, the gasket being confined by the retaining means and being folded over the retaining means and around the inside of the flange, and means for binding the two ends of the tension member in place.

3. In a domestic oven comprising a body with an insulated oven liner and a front-opening access door to define a heated cavity; the invention comprising a door construction having an outer door panel, an inner door liner, and an inner panel, and means for fastening the inner panel to the inner door liner, and widely spaced means of low heat conduction for fastening the inner door liner to the outer door panel, thermal insulation located within the door, the inner panel having a peripheral ange supportinga thermal gasket material that is adapted to bear against the front of the oven when the door is closed, retaining means overlying one longitudinal edge of the gasket on the outer side of the flange, the gasket being doubled over the retaining means and around the inner side of the ange, a second longitudinal edge of the gasket incorporating a draw-string which when tightened serves to place the gasket under tension surrounding the ange.

4. In a domestic oven as recited in claim 3 wherein the retaining means comprises a plurality of flat strips with a series of widely spaced integral tabs that pierce the gasket material and engage the peripheral ange of the inner panel.

5. An insulated door construction comprising a main door structure with an inner panei supported on its innermost side, means of low heat conduction for fasteningthe inner panel to the door, the inner panel having a peripheral flange adapted to be located closely parallel to the inner side of the door; the invention comprising a door sealing gasket of thermal strip material surrounding the peripheral fiange of the inner panel, retaining means overlying one longitudinal edge of the gasket, said retaining means comprising a plurality of flat strips with holding tabs which pierce the gasket material and engage the peripheral ange, the gasket being folded over the retainer means and around the other side of said ange, a second longitudinal edge of the gasket incorporating a ftexible tension member which when put under tension and anchored down serves to stretch the gasket transversely of itself.

References Cited UNITED STATES PATENTS 3,024,074 3/1962 Jacobs et al. 126-198 X 3,121,158 2/1964 Hurko 126-190 X 3,189,020 6/1965 Getman 126--190 3,439,668 4/1969 Tilus 126-190 CARROLL B. DORITY, IR., Primary Examiner U.S. Cl. X.R.

Dedication 3,507,266.-L0uzs A. Vonasoh, Louisville, Ky. OVEN DOOR WITH DOOR SEALING GASKET. Patent dated Apr. 21, 1970. Dedication filed May 28, 1971, by the assignee, General Electric Company. Hereby dedicates to the Public the entire remaining term of said patent.

[Oficial Gazette August 31, 1.971.]

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