Stock material or miscellaneous articles – Structurally defined web or sheet – Edge feature
Reexamination Certificate
1998-10-29
2002-06-04
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Edge feature
C428S121000, C428S195100, C428S210000, C428S447000
Reexamination Certificate
active
06399183
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to plates made of glass material, more particularly designed to equip ranges, such as tempered glass plates or glass-ceramic plates. Such plates made of tempered glass are used more particularly to form the tops of gas ranges, the burners being able to pass through said tempered glass plates. Glass-ceramic plates am designed more particularly to cover heating elements.
While not limited to such applications, the invention will be described more specifically in reference to glass-ceramic plates that make up the top portion of ranges. These types of ranges comprise heating elements such as radiant or halogen heating units and control mechanisms to vary their intensities.
2. Description of the Related Art
These various elements are placed in a structure, usually a metal structure, and covered with a glass-ceramic plate, which closes the structure. Assembly of these cooking surfaces is therefore completed by placing the glass-ceramic plate onto the metal structure. This manufacturing step is accomplished by adhesive bonding using a silicone adhesive, which is suited to this type of use. Indeed, the silicone adhesive performs various types of functions. First of all, it makes it possible to keep the glass-ceramic plate on the structure in a specific position; a range manufactured in this way can be transported easily, since all the elements are attached to one another. Another function of the silicone adhesive is to ensure that the enclosure formed by the metal structure and the glass-ceramic plate remains leak-proof. This enclosure must first have good tightness so that in the event something boils over, water does not get inside and risk causing a short-circuit. Secondly, from a hygienic standpoint, since this type of plate is a tool for preparing food, it is necessary to prevent areas that are difficult to access and impossible to clean from getting dirty in order to avoid germ growth.
Another function of the silicone adhesive is to absorb mechanical impacts: on the one hand, it prevents any direct contact between the metal structure and the glass-ceramic plate, and, on the other hand, it can compensate for the thermal expansion of the metal structure since the glass-ceramic plate has virtually no expansion coefficient. One feature of silicone adhesives is that they have good temperature resistance. Although the silicone adhesive is only used on the periphery of the glass-ceramic plate and therefore at some distance from the heating areas, this temperature resistance is important: first of all the periphery of the glass-ceramic plate nevertheless experiences a rise in temperature when one or more heating units are in operation. Furthermore, a heated item such as a saucepan can be placed on the edge of the plate and thus quickly subject the adhesive to a high temperature.
A final function of the silicone adhesive for certain assemblies is aesthetic in nature: since at least some of the adhesive is applied on top, it is important to be able to smooth it in order to give it an attractive appearance, for at least some will remain visible; silicone adhesive is easy to shape.
On the other hand, this assembly process, which consists in gluing the glass-ceramic plate onto the metal structure using a silicone adhesive, has various disadvantages. First of all, it requires a relatively large quantity of silicone adhesive; the high cost of this product is a first disadvantage. Indeed, it appears that during assembly the quantity of silicone necessary to fill the entire space between the plate and the frame is large; additionally, some of the silicone used is useless or removed. The silicone can be useless when it unintentionally overflows the adhesive area and is removed, particularly during smoothing. Another disadvantage is linked to the polymerization time, which increases with the quantity of material and which also leads to an increase in manufacturing costs, particularly due to the necessity of providing intermediate storage for the plates.
Additionally, another disadvantage particularly linked to this long polymerization time involves the assembly itself The glass-ceramic plates are usually delivered as-is to the range manufacturers who are responsible for the assembly. In theory, this type of factory assembly, where the workers have the necessary tools, does not present any problems. On the other hand, this type of assembly seems much more difficult for a tradesman who must remount a glass-ceramic plate onto a metal structure after making electrical repairs or in order to replace a glass-ceramic plate that has been damaged. It seems to be a difficult task for the tradesman to attach the glass-ceramic plate, for he must place the silicone adhesive on the periphery of said plate, on the internal surface and on the edges, smooth the adhesive in any visible areas, and keep the glass-ceramic plate well-centered while applying pressure during all these operations and during the polymerization time for the adhesive, which is relatively long.
Furthermore, removing this type of glass-ceramic plate previously attached to a metal structure using silicone adhesive is not easy either, particularly for a tradesman. The tradesman must make a cut in the silicone adhesive underneath, i.e., on the internal face of the glass-ceramic plate, and a cut on top, i.e., on the edge of said plate. These two operations, which must be done along the entire periphery, are not simple, for the two cutting lines must meet in order to separate the two elements—glass-ceramic plate and metal structure—successfully. Furthermore, and more particularly when cutting on the internal face of the glass-ceramic plate, it is not easy to make this cut without scratching the internal face of the plate. A scratch can lead to a crack during stress and therefore to a break in the plate. It therefore appears virtually impossible to remove a glass-ceramic plate in order to reinstall it later without damaging the plate. Furthermore, in order to reattach it to the structure, it is necessary to eliminate the traces of silicone adhesive from the previous assembly to the greatest extent possible, which also creates a risk of scratching, particularly on the bottom face of the glass-ceramic plate, thereby making this plate more fragile.
As a consequence, in order to replace or remove a glass-ceramic plate it is now customary to work on the entire plate-metal structure unit, that is, it is first necessary to remove the range top, which is usually built into a cooking surface, then to remove the plate connected to a part of the metal structure from the rest of the metal structure. In no case is it possible at present to consider completely separating the plate from the metal structure onto which it is glued.
SUMMARY OF THE INVENTION
The aim of the invention is to eliminate these disadvantages and more specifically to propose a plate made of glass material such as tempered glass or glass-ceramic for which mounting onto a metal or equivalent structure is less costly than the techniques cited previously, particularly with regard to the adhesive material, and which can be removed and replaced, if necessary, simply and without any danger of damaging the glass-ceramic plate.
The invention also targets this type of plate made of glass material whose the mounting means will ensure tightness, mechanical impact absorption and temperature resistance, and will give the unit an attractive appearance.
These goals are achieved in accordance with the invention by a plate made of glass material such as tempered glass or glass-ceramic designed to be mounted in a frame, a metal frame, for example, comprising at least one polymer strip on its periphery, said strip having on at least one portion of its length a shape that allows the plate to nest with the frame and thereby be fixed inside it.
By periphery is meant the peripheral area of the plate of glass material; that is, the strip can cover at least part of the edge of the plate and/or at least a peripheral part of one surface of said
Grassi Michel
Mikoda Jean-Francois
Vilato Pablo
Eurokera
Hess Bruce H.
Shewareged B.
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