1. Field of the Invention
The present invention pertains to the art of cooking appliances and, more particularly, to a door linkage system for an oven having French-style doors. Even more specifically, the invention is directed to a French-style door seal mounting and timing arrangement designed to minimize seal gasket wear.
2. Discussion of the Prior Art
It is widely known to provide a cooking appliance, such as an oven range or a wall oven, with a single, generally rectangularly shaped door that pivots about a horizontal axis. That is, a top portion of the oven door is pulled outward from the appliance about horizontally disposed hinges and lowered into a horizontal position to provide access to the oven cavity. While this type of oven door has found wide spread use, it is not entirely satisfactory for every application. For instance, an oven door that rotates about a horizontal axis projects outward from the appliance a considerable distance. This distance must be taken into consideration when deciding where to locate the appliance in the kitchen. Otherwise, the opened door could interfere with traffic patterns in the kitchen or with access to other cabinetry. In addition, such an oven door may require a consumer to stand at a side of the appliance to fully access the oven cavity. In order to address this problem, some manufacturers provide their ovens with one or more doors that swing open about substantially vertical axes.
Incorporating French-style doors into cooking appliances is also known in the art. An oven employing French-style doors will typically include a linkage that translates linearly so as to cause both of the doors to open or close when either one of the doors is operated. In this manner, the doors can be operated with only one hand, leaving the other hand free to hold a food item. While this type of door arrangement does address many of the shortcomings associated with horizontally swinging doors, French-style doors include several shortcomings of their own. For example, proper door sealing to avoid excessive heat loss from the oven cavity is an important concern. In at least arrangements employing doors which interengage when closed, in order for the doors to close and seal properly, one of the doors must lag relative to the other. In this manner, a proper seal can be maintained about the oven cavity without requiring a consumer to close each of the doors separately. Moreover, the linkage must properly retain the doors in the closed position in order to ensure that hot oven gases do not escape. Other areas of concern include providing end stops or detents so that the doors do not inadvertently swing shut.
The timing of the doors is actually crucial to the sealing properties of the cooking appliance. In particular, if the timing is off, undue seal wear can occur, resulting in undesirable heat losses from the oven cavity during use of the appliance. Known in the art is the use of stainless door wipers. These wipers are resilient, but do not follow contours easily and are prone to have gaps at their ends. Typically, a continuous glass fiber based seal is employed to close these corner gaps in order to maintain a tighter seal between the oven cavity and the door, while also being easier to install. Certain other types of known seals, such as silicone gaskets, will not stand up to self clean temperatures. Attempts have actually been made to provide silicone gaskets on the inside edges of both doors with a door timing wherein both doors are matched in their opening positions. Generally the consumer will open the doors using one handle. This biases the door timing mechanism, causing one door to move first and the gaskets to slide against each other. Simply stated, a fiber based seal will not withstand this wear. Improved quality in the mechanism could reduce the wear but is considered to be too expensive.
Therefore, despite the existence of French-style doors employed in cooking appliances of the prior art, there still exists a need for a French-style oven door mounting and timing system which provides for minimal wear on the gasket or sealing arrangement.
The present invention is directed to a closure system for a cooking appliance including an oven cavity closed by a pair of laterally spaced, French-style doors. In accordance with the invention, the cooking appliance includes a cabinet shell and an oven cavity arranged within the cabinet shell, with the oven cavity having top, bottom, rear and opposing side walls that collectively define a frontal opening. The cooking appliance is provided with first and second doors that are pivotally mounted relative to the cabinet shell for selectively closing the frontal opening of the oven cavity. More specifically, the first and second doors constitute French-style doors that open about substantially vertical axes.
The first and second doors are interconnected through the door linkage system. More specifically, the door linkage system interconnects each of the first and second doors to one another, as well as with the cabinet shell. The door linkage system includes a first door control arm having a first end, which is pivotally mounted to the first door, and a second end. The door linkage system also includes a second door control arm having a first end, which is pivotally mounted to the second door, extending to a second end that is pivotally connected to the second end of the first door control arm.
The second ends of the first and second door control arms are mounted in such a manner so as to travel in arcuate paths when either one of the first and second doors is operated. More specifically, when one of the first and second doors is moved in either an opening or a closing direction, the second ends of the first and second door control arms travel over the arcuate paths, causing the other of the first and second doors to move in a corresponding direction.
At least one of the door control arms has associated therewith a camming surface upon which rides a corresponding cam follower as the doors transition between open and closed positions. The overall cam follower arrangement provides a sealing force to the first and second doors in the closed position. Additionally, the camming surface is provided with a plurality of detents that establish various, selectable positions for the doors. That is, the detents engage with the cam followers in order to selectively retain the first and second doors at any one of various locations ranging from a fully open position to a fully closed position, with at least one detent residing at the fully open position to ensure that the first and second doors do not inadvertently swing closed.
The first and second control arms are operatively connected to a support bracket through a linkage control arm. The linkage control arm establishes the arcuate path tracked by first and second ends of the door control arms, as well as a particular timing of the doors. With this arrangement, as the doors transition between the open and closed positions, the linkage control arm engages the cam follower. The cam follower travels along the camming surface to provide for a smooth transition.
Each of the doors has an associated gasket for use in sealing the oven cavity when the doors are closed. In accordance with the invention, one of the doors is provided with an annular gasket, while the other door essentially incorporates a less that fully annular, preferably 3-sided, gasket. Most preferably, a three-quarter gasket is employed. With this arrangement, each of the gaskets has three sides adapted to seal against the cabinet shell, while the fourth side of the first gasket is adapted to seal against an extension provided on the other door. An important aspect of the invention is to minimize abrasion on the first gasket by designing both the gasket contact point or line, and the door timing so as to produce a contact arrangement similar to that exhibited with standard single door units.
In connection with the invention, the gasket configurations and constructions, along with the construction and operation of the door linkage system, combine to provide a synergistic effect in minimizing potential wearing of the seal arrangement. To this end, the timing of the opening and closing of the doors is important. The door linkage system overcomes an issue of slop in the mechanism by intentionally moving one door farther than the other when the doors are first opened. Instead of the doors opening evenly, one door initially moves significantly farther than the other, breaking the contact between the first gasket and a mating portion of the other door. In the most preferred form of the invention, the oven cavity/cabinet shell, as well as the door extension, is provided with a porcelain coating. With this construction, each of the gaskets is only seated against porcelain coated surfaces to minimize wear caused by surface roughness.
In accordance with the invention, the annular gasket does not make contact with the side of the other door panel. If placed in this position, the gasket would be compressed as the doors are opened, loose its ability to return to shape after being subjected to the high temperatures of several self cleaning operations, and not return to a shape needed for properly sealing the doors. Instead, the fourth side, or center seal, of the gasket on the first door contacts the extension of the opposite door. This extension places the contact surface mostly behind the gasket. As the doors are opened, the timing established by the linkage system pulls the gasket away from the sealing surface behind it. By breaking the contact early in the door opening process, the seal is saved from any unnecessary crushing or abrasion.
An additional feature of the invention is that different rates of movement are imparted to the doors when nearing closed positions in order to help assure good contact of the center seal. The timing established by the linkage system will continue to pull the doors closed until the center seal or gasket makes contact, thereby providing a mechanically advantaged force to balance a force applied by a door closure spring. In any case, additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.
With initial reference to
In a manner known in the art, cooking appliance 2 includes a control panel 38 having a plurality of control elements. In accordance with the embodiment shown, the control elements are constituted by first, second and third sets of oven control buttons 40-42, as well as a numeric pad 43. Control panel 38 is adapted to be used to input desired cooking parameters and establish operating conditions for cooking appliance 2. More specifically, first, second and third sets of control buttons 40-42, in combination with numeric pad 43 and a display 45, enable a user to establish particular cooking operations that are performed within oven cavity 6. As the oven control is known in the art and does not form part of the present invention, it will not be discussed further herein.
In accordance with the invention, cooking appliance 2 is provided with French-style doors that are adapted to selectively seal across frontal opening 14. More specifically, cooking appliance 2 includes a first door 52 and a second door 53 that are pivotally mounted relative to frame 4 and adapted to be moved from a fully closed position, as represented in
In a manner known in the art, each door 52, 53 is provided with a corresponding outer panel 57, 58 having a respective central transparent zone or window 59, 60. In addition, each door 52, 53 is provided with a corresponding handle 61, 62 that enables a consumer to shift doors 52 and 53 between open and closed positions. In order to provide a proper seal about frontal opening 14, each door 52, 53 includes an inner panel 65, 66 about which extends a peripheral seal or gasket as discussed in detail below. In addition, first door 52 is provided with a flange 67 that serves as an intermediate sealing surface for second door 53. That is, when both first and second doors 52 and 53 are moved to the closed position of
Reference will now be made to
In accordance with the invention, linkage system 200 includes a stationary control arm or support member 237 having a first end 238 fixedly mounted relative to frame 4 and extending to a second end 239 through an intermediate portion 240. In a manner which will be discussed more fully below, a section of intermediate portion 240 includes a camming surface 242. First and second control arms 210 and 218 are operatively connected to support member 237 through a linkage control arm 244. More specifically, linkage control arm 244 includes a first end 247 pivotally connected to intermediate portion 240 of support member 237 at a pivot point or axis 249. First end 247 extends to a second end 254 through an intermediate portion 258. For reasons which will be described more fully below, second end 254 is provided with a plurality of openings, indicated generally at 260.
In accordance with this form of the invention, linkage system 200 includes a tensioning bracket 284 connected to linkage control arm 244 through a pivot pin 285. Tensioning bracket 284 includes a first end 286 that extends to a second end 287. Second end 287 is provided with a plurality of apertures, indicated generally at 289. With this arrangement, a spring 292 is fastened at one of the plurality of apertures 289 and one of the plurality of openings 260 on linkage control arm 244 to provide tension to first and second control arms 210 and 218. More specifically, by selecting between the plurality of apertures 289 and/or plurality of openings 260, a desired tension can be placed on linkage control arm 244. In any event, tensioning bracket 284 is shown to include a cam follower 294 provided at first end 286. As will be described more fully below, cam follower 294 cooperates with camming surface 242 and linkage control arm 244 to guide doors 52 and 53 between a closed position, as represented in
As best shown in
At this point, it is possible to shift doors 52 and 53 to the closed position as represented in
At this point, it should be understood that various linkage systems can be designed to carry out the required closure timing of the French-style doors for the cooking appliance of the invention. For instance, the linkage systems disclosed in pending U.S. patent application Ser. No. 11/206,219 entitled “Door Linkage System for an Oven Having French-Style Doors”, the disclosure of which is hereby incorporated by reference, could be employed. Even if the linkage system is varied, it is important to provide flexibility for setting the particular timing of the closing of the doors in order to prevent undue wear on door seals.
This advantageous feature of the invention is best seen in connection with
As clearly shown in
Based on this construction, the particular structure and arrangement of gaskets 305 and 335 themselves provide for enhanced seal life. In particular, door linkage system 200 of the present invention overcomes an issue of slop in the mechanism by intentionally moving one of doors 52 and 53 farther than the other of doors 52 and 53 when doors are first opened. For example, instead of doors 52 and 53 opening evenly, door 52 initially moves significantly farther than door 53, breaking contact between gasket 305 and a mating portion or extension member 315 of door 53. In the most preferred form of the invention, the oven cavity 6/cabinet shell 4, as well as extension member 315, is provided with a porcelain coating. With this construction, each of gaskets 305, 335 is only seated against porcelain coated surfaces to minimize wear caused by surface roughness.
As discussed above, annular gasket 305, or more particularly gasket side member 357, does not make contact with the side (not separately labeled) of door 53. Instead, the gasket side member 357 of gasket 305 contacts extension member 315 of door 53. Extension member 315 places the contact surface mostly behind gasket 305. As doors 52 and 53 are opened, the timing established by linkage system 200 pulls gasket 305 away from extension member 315. By breaking the contact early in the door opening process, gasket 305 is saved from any unnecessary crushing or abrasion.
An additional feature of the invention is that different rates of movement are imparted to doors 52 and 53 when nearing closed positions in order to help assure good contact of the center seal. That is, the timing established by linkage system 200 continues to pull doors 52 and 53 closed until gasket side portion 357 makes contact with extension member 315, thereby providing a mechanically advantaged force to balance a force applied by a door closure spring (not separately labeled). In any case, although described with reference to preferred embodiments of the present invention, it should be readily apparent to one of ordinary skill in the art that various changes and/or modifications can be made to the invention without departing from the spirit thereof.
The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/793,251 filed Apr. 20, 2006 entitled “French Door Cooking Appliance Closure System.”
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