US3507267A - Windowed oven door - Google Patents

Description

April 1970 JEAN-CLAUDE R. LAFFORGUE 3, 07,267

WINDOWED OVEN DOOR BY LAFFORGUE 18 mw M M A E J 4 Sheets-Sheet 2 O 4 n /NM3 4 15 H as ATTORNEY April 21, 1970 JEAN-CLAUDE R. LAFFORGUE WINDOWED OVEN DOOR 4 Sheets-Sheet} Filed Sept. 25, 1968 INVENTOR. JEAN-CLAUDE F G. 5 LAFFORGFEJE orm HIS ATTORNEY April 21, 1970 JEAN-CLAUDE R. LAFFORGUE ,50

. WINDOWED OVEN DOOR Filed Sept. 25, 1968 4 Sheets-Sheet u J? ixi L W 50 W INVENTOR. JEAN-CLAUDE R.

BY LAFFORGUE ms A'r'ronum United States Patent O 3,507,267 WINDOWED OVEN DOOR Jean-Claude Ren Lafforgue, St. Laurent, Quebec, Canada, assignor to Canadian General Electric Company Limited, Toronto, Ontario, Canada Filed Sept. 25, 1968, Ser. No. 762,584 Claims priority, application Canada, July 12, 1968, 4 93 Int. Cl. r zsm 7/00 US. Cl. 126200 7 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to windowed oven doors and particularly to an improved door for use with high temperature ovens such as self-cleaning baking ovens wherein the oven wall temperatures may reach as high as 950 F. to 1000- F.

Windows have been available in conventional oven doors for many years now and housewives have become accustomed to the convenience of being able to observe the food being cooked in the oven without having to openthe oven door. In a self-cleaning oven as set forth in Hurkos US. Patent No. 3,121,158 dated Feb. 11, 1964, which is cleaned by a pyrolysis process during which the temperature in the oven is raised well above the normal cooking temperature range of 150 F. to 550 F. to somewhere within a range between about 750 F. and about 950 F., the conventional windowed oven doors cannot be used as they are not capable of confining the extra heat to the oven cavity.

It is therefore, the principal object of this invention to provide a windowed oven door for use with high electric control circuit for the self-cleaning heating means including an electric interlock switch which is normally open to prevent activation of the heating means. In my US Patent No. 3,440,403 dated Apr. 22, 1969 such an electric control circuit is disclosed and claimed in which the interlock switch is closed by a latch mechanism when locking the fully closed oven door.

It is a further object of this invention to provide a windowed oven door including a movable reflective shield which is adapted to cooperate with a door latching mechanism so that the door cannot be locked by this mechanism unless the reflective shield is covering the window.

The present invention achieves this object by providing a door construction for a high temperature oven comprising an outer door panel with a first window opening, a double-pane window assembly covering said first window opening, an inner door liner attached to and spaced inwardly from said outer door panel, a second window opening in said inner door liner in alignment with said first window opening, a single pane window covering said second window opening. A slidable shield is located between said outer door panel and said inner door liner for movement to a position between said double-pane window assembly and said single pane window to obstruct the view and restrict the radiation of heat through said window openings. Lever means have one end pivotally secured to said shield at the top corners thereof and are provided at the other end with shank means extending therefrom at substantially a right angle and terminating in a knob. Guide means in the form of slots are provided in said inner door liner and extend along both sides of said window opening in a substantially vertical direction for receiving said shank means so as to slidably secure said lever means. The upper ends of siad slots terminate in an outwardly directed, inverted substantially U-shaped configuration for receiving said shank means and thereby securing said shield in a window closing position.

My invention will be better understood from the following description taken in conjunction with the accompanying drawings and its scope will be pointed out in the appended claims.

FIGURE 1 is an elevational view toward the inner liner of a windowed oven door separated from the oven.

FIGURE 2 is a reversed view of FIGURE 1 with the outer door panel removed.

FIGURE 3 is a cross-sectional, elevational view of the door along the line 33 of FIGURE 1 on an enlarged scale.

FIGURE 4 is also on an enlarged scale a partial, elevational view of the inner door liner shown in FIG- URE 2.

FIGURE 5 is a cross-sectional, elevational view along the line 5-5 of FIGURE 4.

FIGURES 6 and 7 are similar views as shown in FIGURE 4 illustrating the reflective shield and its actuating mechanism in different operative positions.

Referring now to FIGURES 1, 2 and 3 there is shown an oven door 11 of sheet metal construction having three main elements, an outer door panel 12, an inner door liner 13 and an inner panel 14 supported from the inner door liner 13. The outer door panel 12 is of a shallow pan-shape and has a rearwardly turned, periph eral flange 15. The inner door liner 13 is also of shallow pan-shape and of mating construction with the outer door panel 12, in that it has a front-turned peripheral flange 16 which telescopes within the flange 15 of the outer door panel 12. The inner panel 14 is likewise of shallow pan-shape having a front-turned peripheral flange 17. It is secured to the inner door liner 13 whereby a high temperature gasket 18 is sandwiched between the periphery of inner panel 14 and inner door liner 13. This door panel 14 serves as a close-fitting plug to close the oven cavity of a range or similar cabinet and to increase the distance between the front panel 12 and the inner surface of the oven door exposed to the oven cavity so as to restrict the rise of temperature of the outer walls of the range when the oven is operating at heat cleaning temperatures. Outer door panel 12, inner door liner 13 and inner panel 14 are connected to each other by suitable fastening means in a well known manner. The oven door 11 is also provided with a door handle 19 at the top portion thereof and with hinge means 20 for connecting it to corresponding hinge means attached to the oven.

A high temperature, transparent window 21 is formed in the oven door 11 for viewing the food while it is being cooked. This window is so constructed that it is protected from the high temperature experienced in the oven cavity during the self-cleaning operation. For this purpose, a window opening is provided in each of the three door elements; namely, an opening 22 in outer door panel 12, an opening 23 in inner door liner 13 and an opening 24 in inner panel 14. The openings are in alignment and each is closed with a transparent pane or sheet such as glass so as to improve the thermal insulation and retard heat flow. As best shown in FIGURE 3 the window structure incorporates three such panes 25, 26 and 27. The two frontmost panes 25 and 26 are first assembled on a continuous spacer frame 28 and they are held together by an outer frame 29 of U-shaped transverse cross-section which slips around the periphery of the two panes to form a complete sub-assembly. A decorative trim frame 30 of acute angular shape in transverse cross-section extends around the periphery of the front edge of the outermost pane 25 and it is likewise held in place by the outer frame 29. This double pane sub-assembly is connected to the back side of the outer door panel 12 by means of support brackets 32 and 34.

The third transparent pane 27 made of high temperature resistant material such as borosilicate glass is fastened over window opening 24 in the inner door liner 13 from the inner side thereof by means of fasteners and clip members 35 and 36. In order to seal this pane against the escape of gases and vapors around the edges thereof, a high temperature resilient gasket 37 is sandwiched between the pane 27 and the peripheral edge of the window opening 23. A decorative trim frame 38 is assembled around the peripheral edges of the pane 27 so as to mask the edge from view. This trim frame 38 telescopes into window opening 24 of the inner panel 14. Substantial spaces 39 and 40 are provided between the inner panel 14 and inner door liner 13 and between guards 31 and 33 mounted between inner door liner 13 and outer door panel 12, which spaces are filled with a thermal insulation such as glass fiber.

As best shown in FIGURE 3, a chamber 41 is formed between outer door panel 12 and inner door liner 13 in which a reflective shield or shutter 42 is accommodated. The reflective shield or shutter 42 is primarily useful during the high temperature, self-cleaning operation during which it is raised in a position between the double pane unit 25, 26 and the innermost pane 27. In this position it prevents the escape of much of the radiant energy from within the oven cavity and this serves to increase the operating temperature of the pane 27 and thereby automatically decomposes the food soil therefrom during the high temperature heat cleaning operation. During normal cooking operation, the shield 42 would be moved down into the bottom of chamber 41 beneath the opening (FIGURES 2 and 3) where it will be out of sight and not restrict the view of the food being cooked. Since the height of the chamber portion below the window openings is in most cases smaller than the height of the window openings and since it is desirable that the reflective shield completely disappears from view during the normal cooking operation, shield 42 may be horizontally split in two parts 43 and 44 which are secured together by a lost-motion connection means. This lost-motion connection means could be provided, as best seen in FIGURES 3 and 4, by two studs 45 located at opposite sides of part 44 adjacent its lower edge which slidably engage two slots 46 extending adjacent and along the side edges of part 43.

The movement of the reflective shield 42 is effected (see FIGURES 1 and 2) by a pair of levers 47 and 48 pivotally secured to part 44 of shield 42 at the top corners thereof. The free ends of these levers are provided with shank means 49 and 50 extending from the levers at right angles and terminating in knobs for better manipulation. The shank means are slidably engaged in slots 51 and 52 provided in the inner door liner .13. The upper ends of these slots terminate in an outwardly directed, inverted U-shape to give the slots a cane-like configuration. Thus, the slots serve as a guide means for the shank means 49 and 50 when moving the reflective shield 42, and the U-shaped end portion provides a detent means to lock the shield in its window closing position. It is worthwhile to note that the two shanks 49 and 50 are inaccessible when the oven door is closed. Hence it is only when the door is in an open position that the shield can be moved from an open to a closed position and vice versa. It is also preferable to provide guide means (not shown) for the proper movement of the reflective shield 42 within the door.

As pointed out before, in a high temperature selfcleaning oven it is very important for safety reasons to provide a locking means for the oven door 11 to insure that the high temperature cycle cannot be initiated unless the door is locked and also that the door cannot be unlocked unless the oven has cooled down to normal cooking temperatures. Such a locking means is disclosed in my aforementioned US. Patent No. 3,440,403. It includes a latch mechanism having a hook-like latch member located in the range cabinet which when actuated, swings in a horizontal plane out through a slot in the front wall of the range cabinet and engages a latch receiving or keeper slot 53 provided in the inner door liner 13 (FIGURES 1 and 2). The latch mechanism is equipped with an interlocking switch interposed in the power circuit to the oven heating means which closes the circuit to the heating means only when the door is closed and locked. To insure this, the keeper slot 53 is adapted to be closed by latch guards 54 and 55 extending in tandem arrangement along the upper edge of the oven door 11. The abutting ends of both guards interfere with the access to slot 53 while the other ends of the guards adjacent the corners of the oven door are rotatably secured to the inner door liner 13 at pivot points 56 and 57. The abutting ends of the guards are further linked to each other by a tongue 58 projecting from guard 55 and entering into a slot 59 provided on guard 54. Both guards are additionally biased into their slot interfering position by slide levers 60 and 61 which are pivotally secured to the inner door liner 13 adjacent its lower edge at pivot points 62 and 63. These slide levers extend upwardly towards the end portions of guards 54 and 55 where their free ends terminate immediately beneath flanges 64 and 65 (FIGURE 5) extending at a right angle from guard levers 54 and 55 respectively. The upper part of levers 60 and 61 include vertically extending slots 66 and 67 which in the biasing position are in alignment with slots 51 and 52 provided in the inner door liner 13. Shank means 49 and 50 projecting from levers 47 and 48 are also extending through slots 66 and 67. The upper ends of levers 60 and 61 are slotted to define offset tongues 68 and 69. The gap between these tongues and the remaining end portions of the levers are so dimensioned to accept the end portions of latch guards 54 and 55 as seen in FIGURE 5 for guard 54. The end portions of latch guards 54 and 55 are provided with a cut-out defining re-entrant cam surfaces 70 and 71, the re-entrant portions forming stop members 72 and 73.

From the previous description it is apparent that the high temperature self-cleaning cycle cannot be initiated unless the window is first closed by raising the reflective shield 42. If such an attempt were made with the reflective shield 42 in its lowered or hidden position as illustrated in FIGURE 2, the hook-like latch member swinging out in a horizontal plane through a slot in the front wall of the range would strike the latch guards 54 and 55 covering keeper slot 53 and be prevented from moving to a closed and locked position. Thus, the interlocking switch cannot be actuated by the latch member and the attempt is successfully stopped. To effect the high temperature heat cleaning operation, the oven door is opened and the reflective shield 42, is moved to close the window by gripping the knobs of shanks 49 and 50 and sliding them along slots 51, 66 and 52, 67 as shown in FIGURE 4. First, part 44 of the shield alone will move upwarly whereby studs 45 slide along slots 46 in part 43 of the shield until they have arrived at the end of the slots. From then on the complete shield will move upwardly and finally cover completely the window. When shanks 49 and 50 enter the outwardly directed, inverted U-shapes at the end of slots 51 and 52, the levers 60 and 61 will slide outwardly as illustrated in FIGURE 6. Thereby the top ends of levers 60 and 61 will leave their positions underneath flanges 64 and 65 and remove the biasing effect on latch guards 54 and 55. As the shanks 49 and 50 move down to the end of the inverted U-shapes, they contact stop members 72 and 73 and push them downward. As illustrated in FIGURE 7, this tilts latch guards 54 and 55 about the pivot points 56 and 57 and the access to slot 53 is free. Upon closing the door, the high temperature self-cleaning operation may proceed without further restriction.

Modifications of this invention will occur to those skilled in the art. For instance, the new mechanism could also operate with the use of only one slide lever and one latch guard. However, as shown and described in the preferred embodiment of this invention, the use of two slide levers and two latch guards provides a more eflicient and balanced mechanism. This condition is further enh inced by the tongue and slot connection between the free ends of latch guards 54 and 55. It is also obvious that the novel reflective shield arrangement can be used successfully in a windowed oven door where the double pane window is replaced by a single pane. If the available space permits it, the reflective shield itself can be of a laminated structure having a layer of thermal insulation material located between the laminates. Such a shield will further decrease heat losses through the window during the heat cleaning operation. It is, therefore, to be understood that this invention is not limited to the particular embodiment disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this inventi )n as claimed.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A door construction for a high temperature oven comprising:

(a) an outer door panel with a first window opening,

(b) a double-pane window assembly covering said first window opening,

(c) an inner door liner attached to and spaced inwardly from said outer door panel,

((1) a second window opening in said inner door liner in alignment with said first window opening,

(e) a single pane covering said second window open- (f) a slidable shield located between said outer door panel and said inner door liner for movement to a position between said double-pane window assembly and said single pane to obstruct the view and restrict the radiation of heat through said window openings,

(g) a pair of lever means each having one end pivotally secured to said shield adjacent the top corners thereof and provided at the other end with shank means extending therefrom at substantially a right angle and terminating in a knob, and

(h) guide means in the form of slots provided in said inner door liner and extending along both sides of said'window opening in a substantially vertical direction for receiving said shank means so as to slidably secure said lever means, the upper ends of said slots terminating in an outwardly directed, inverted substantially U-shaped configuration for receiving said shank means and thereby securing said shield in a window closing position.

2. A door construction as defined in claim 1 including a door latch receiving slot adjacent the upper edge of said door a latch guard extending along said upper edge from one of the door corners towards said door latch receiving slot, the end of said latch guard adjacent the door corner rotatably secured to the inner door liner, the other end being positioned so as to interfere with the access to said door latch receiving slot, a slide means pivotally secured to the inner door liner adjacent the lower edge thereof, said slide means extending upwardly towards the end of said latch guard adjacent said door corner and cooperating with said latch guard so as to bias its free end into a position obstructing the access to said latch receiving slot, said slide means having a slot in alignment with one of the slots provided in said inner door liner for receiving the shank means of one of the levers connected to said shield, said shank means being also received within said slot in said slide means so that movement of said shield into a window closing position releases said latch guard and moves its free end out of the latch receiving slot obstructing position.

3. A door construction as defined in claim 2 having two latch guards in tandem arrangement with their ends adjacent the door corners rotatably secured to the inner door liner and their free ends positioned in an end-abutting relationship, and two slide means extending along both sides of said door window.

4. A door construction as defined in claim 3 wherein the abutting free ends of said latch guards are interlocked.

5. A door construction as defined in claim 3 wherein said slide means are positioned between said inner door liner and said lever means, one end of said slide means pivotally secured to said inner liner of said door adjacent the lower rim thereof while the other ends are provided with slots substantially in alignment with the slots in said inner door liner, the shank means of said lever means extending through both of said slots and thereby linking said slide means with said lever means.

6. A door construction as defined in claim 1 wherein said shield is horizontally divided in two parts which are secured together by a lost-motion connection means.

7. A door construction for a high temperature oven having an oven cavity formed by a box-like oven liner and a front-opening access door comprising:

(a) an outer door panel with a first window opening,

(b) a double-pane window assembly covering said first window opening,

(c) an inner door liner attached to and spaced inwardly from said outer door panel,

(d) a second window opening formed in said inner door liner in alignment with said first window opene,

(e) an inner door panel of reduced size compared to the outer door panel and the inner door liner attached to the inner door liner and forming a wall of said oven cavity,

(f) a third window opening formed in said inner door panel in alignment with said first and second window openings,

( a single pane covering said second and third window openings,

(h) a slidable reflective shield located between said outer door panel and said inner door liner for movement to a position between said double-pane window assembly and said single pane to obstruct the view and restrict the radiation of heat through said window openings,

(i) a pair of lever means each having one end pivotally secured to said shield adjacent its top corners and provided at the other end with shank means extending therefrom at a substantially right angle and terminating in a knob,

(j) guide means in the form of slots provided in said inner door-liner and extending along both sides of said window opening in a substantially vertical direction for receiving said shank means so as to slidably secure said lever means, the upper ends of said slots terminating in an outwardly directed, inverted and substantially U-s'haped configuration for receiving said shank means and thereby securing said shield in a window closing position,

(k) a door latch receiving slot provided adjacent the upper rim of said door,

(1) latch guards extending along said upper rim in an end-abutting relationship, and

(m) slide means pivotally secured to the inner liner of said door adjacent the lower edge thereof and extending upwardly towards the outer ends of said latch guards thereby biasing them to a position which obstructs said latch receiving slot, said slide means References Cited UNITED STATES PATENTS 3,311,106 3/1967 Baughman et al. 126200 3,362,396 1/1968 Hurko 126-200 3,396,717 8/1968 Winkler et al. 126-200 3,439,669 4/1969 Winkler 126200 having slots substantially in alignment with the slots 15 CARROLL B. DORITY, JR., Primary Examiner

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