Cooktop unit for mounting in a frame structure or a cutout

The invention is directed to a cooktop unit for mounting in a frame structure or in a cutout of a work surface. The cooktop unit includes a plate made of glass ceramic and this plate defines the cooking surface. The cooktop unit also includes a metal frame permanently-elastically connected by a silicone adhesive to the lower side in the peripheral region of the plate. A leg of the holding frame connected to the cooktop plate extends flush from the edge of the plate inwardly and parallel to the plate and then bends downwardly at right angles to the plate. The adhesive effects the force-tight connection or bond between the plate and the holding frame. The adhesive defines a peripheral silicone flange at the lateral edges of the plate and at the lateral edge of the leg cemented to the plate. This silicone flange terminates flush with the surface of the plate and projects beyond the lower edge of the leg connected to the plate to form a sealing lip.

FIELD OF THE INVENTION 
The invention relates to a cooktop unit for mounting in a frame structure 
or in a cutout such as in a plate defining a work surface such as a 
kitchen countertop. The cooktop unit includes a plate made of glass 
ceramic or a similar material and a holding frame adapted for seating on 
the frame structure or in the cutout. The glass ceramic functions as a 
cooktop and the holding frame made of metal is joined by a silicone 
adhesive to the lower side of the plate at the peripheral region thereof. 
The silicone adhesive defines a permanent-elastic bond and the holding 
frame is formed as an angle member having an L-shaped section with one leg 
thereof being bonded to the cooktop. This leg extends flush from the 
lateral edge of the plate and parallelly with the plate inwardly and then 
bends downwardly at right angles to the leg bonded to the plate. 
BACKGROUND OF THE INVENTION 
A cooktop unit generally comprises: a glass-ceramic cooktop or a cooktop 
made of similar material; a holding frame; and, a permanent-elastic 
connection between the cooktop and the frame. 
Assemblies are known in the marketplace having a molded-on sealing profile. 
This idea in and of itself is good but experience has shown that 
significant tolerance problems develop when attempting to realize such 
sealing profiles. This is the case because a seal can be effected only via 
the periphery and therefore a pressfit must always be ensured. This, 
however, is not possible because of the tolerances of the cooktop and 
frame as well as mounting tolerances. 
An inadequate seal between the glass-ceramic cooktop and the frame can 
affect cleaning in practical use and safety during operation. Food being 
cooked can overflow and trickle into the gap between the seal and the 
frame and can disadvantageously affect electrical reliability. 
U.S. Pat. No. 4,363,956 discloses a glass-ceramic cooktop unit for direct 
mounting in a workplate of wood, ceramic or plastic (kitchen countertop). 
This cooktop unit comprises a cooking area with a cookplate made of glass 
ceramic and the heating elements as well as a peripherally extending 
mounting frame supporting the cooktop. The mounting frame can be 
connected, on the one hand, to a peripheral region of the cookplate and, 
on the other hand, to the periphery of a workplate cutout. Spring elements 
and adjusting devices are arranged between the cooking area and the 
mounting frame in order to bring the cooking plate with the cooking area 
in smooth approximation to the frame against the action of the spring 
elements. 
U.S. Pat. No. 5,036,831 discloses a frameless glass-ceramic cooktop unit 
which includes the following: a cooktop with a mounting cutout and a 
peripheral edge in the mounting cutout which includes a flange directed 
downwardly; a glass-ceramic plate having a peripheral edge; a uniform 
support ring having first and second essentially planar surfaces with the 
second planar surface being arranged vertically; and, a sealing material 
between the first planar surface of the support ring and the lower side of 
the glass-ceramic plate. This sealing material joins the glass-ceramic 
plate to the support ring and the second planar surface of the support 
ring is held against the downwardly extending flange. 
The configurations suggested in U.S. Pat. Nos. 4,363,956 and 5,036,831 have 
been difficult to realize in practice because complex configurations of 
the mounting frame and adjusting devices and spring elements are expensive 
to produce and are problematic with respect to installation. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a cooktop unit without the 
above disadvantages. It is another object of the invention to provide a 
cooktop which can be mounted in a simple manner and is easily accessible 
for service. A permanent elastic and tight bond between the glass-ceramic 
plate and the holding frame is ensured even when geometric tolerances are 
present between the glass-ceramic plate and holding frame. In addition, it 
is an object of the invention to ensure the safety of the user at all 
times. 
It is still another object of the invention to provide a preassembled 
cooktop unit which includes an adhesive on the lateral edges of the plate 
and the leg of the holding frame cemented to the plate. The adhesive 
effects a form-tight connection between the plate and the holding frame. 
The adhesive forms a peripheral first flange and this flange extends flush 
to the surface of the plate and the adhesive forms a second flange which 
projects beyond the lower side of the leg connected to the plate to form a 
sealing lip. 
The sealing connection between the first and second flanges and the sealing 
frame or the mounting cutout is now not effected via the vertical sealing 
periphery, but instead is placed in the horizontal plane. The solution 
provided by the invention is in the form of a molded-on sealing lip and 
surprisingly meets all requirements in a simple manner. 
The cooktop unit of the invention therefore includes: a cooktop made of 
glass ceramic or a similar material; a holding frame; and, a 
permanent-elastic formed adhesive flange defining a sealing lip. 
The sealing lip defines the seal between the cooktop unit and the sealing 
frame or the mounting cutout independently of the manufacturing and 
assembly tolerances of the cooktop, on the one hand, and of the sealing 
frame or the mounting cutout, on the other hand. 
The sealing action in the embodiment of the invention is not effected via 
the vertical flank of the adhesive flange but instead via a formed sealing 
lip. For this reason, one is no longer restricted by the high requirements 
as to tolerances of the adhesive device, the sealing frame and the 
mounting cutout. 
The seal can therefore be simply and quickly produced. 
Two methods of producing the seal are especially preferred. The first is to 
produce the seal in a so-called mold or form in which the cooktop unit is 
to be completely preassembled. In order later to be able to easily remove 
the cooktop unit, a separating means is introduced into the mold or the 
mold itself is made of a suitable material such as polytetrafluoroethylene 
(PTFE) which, in and of itself, exhibits a separating action. A second 
method provides for producing the cooktop unit directly in the frame. 
In a preferred embodiment, the thickness of the flange formed by the 
adhesive is 1.5 mm to 3.5 mm and the sealing lip has a radius .ltoreq.0.5 
mm. In this way, a reliable operation of the frame is always obtained. 
The preassembled cooktop unit having the sealing lip can be mounted in any 
conventional frame. A good seal is provided with the sealing lip of the 
invention for sealing frames having a separate support leg as well as for 
sealing frames made of deep-drawn profiles or extrusion profiles made of 
metal or plastic and also for simple mounting cutouts such as a sheet 
metal pan of a hob. 
The connection of the cooktop unit of the invention to the sealing frame is 
provided in a simple manner such as by means of a bendable lug which is 
provided on the leg cemented to the lower side of the glass-ceramic plate 
or on the leg extending freely downwardly and is so bent over that it 
provides a form-tight connection to the sealing frame. Further 
possibilities of providing the connection to the sealing frame are wedges 
such as plastic wedges or by a threaded connection using a threaded bolt.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
FIGS. 1a and 1b show a finished cooktop unit 1 which includes a 
glass-ceramic plate 2 and a holding frame 3 formed as an angle member 
having an L-shaped section. The holding frame 3 is joined to the lower 
side of the glass-ceramic plate 2 by a silicone adhesive 5. The silicone 
adhesive 5 then defines a 2.5 mm thick silicone flange 4 on the lateral 
edge of the plate 2. The silicone flange defines a sealing lip 6 which 
also projects over the peripheral edge of the frame 3. 
FIG. 2 shows the concept pursuant to which the completed cooktop unit 1 
having the sealing lip 6 is produced. The cooktop unit is produced with 
the aid of a form V made of polytetrafluoroethylene. In this way, an 
otherwise necessary separation means 8 is no longer necessary. The form 
corresponds to the negative of a modified original sealing frame. 
FIG. 2 shows a glass-ceramic plate 2 bonded to a frame 3 by means of a 
permanent-elastic silicone adhesive 5. The frame 3 is placed upon the form 
V. The silicone adhesive 5, which later forms the silicone flange 4, is 
introduced between the form V and the lateral edges of the glass-ceramic 
plate 2 and between the form and the holding frame 3. The form V is so 
configured that the silicone flange 4 is formed downwardly to form a 
sealing lip 6 which projects clearly beyond the leg of the holding frame 3 
by 3 mm. This leg of the holding frame 3 is joined to the glass-ceramic 
plate 2. 
The assembled cooktop unit 1 shown in FIGS 1a and 1b is then removed from 
the form and seated in the original sealing frame. 
The manufacture by means of a slightly modified original sealing frame 
takes place in a simple manner. However, the frame must be provided with 
separating means. 
FIG. 3 shows the simple sealing by means of the sealing lip 6 of the 
preassembled cooktop unit 1 mounted in a sealing frame 9 having a separate 
support leg 10. 
FIG. 4 shows the cooktop unit 1 of the invention mounted in a sealing frame 
9 which is made of metal or plastic by means of deep drawing or extrusion. 
FIG. 5 shows the cooktop unit 1 of the invention in a mounting cutout 11 
such as a sheet metal pan of a hob. 
FIGS. 6a to 6d, FIGS. 7a and 7b, FIG. 8 and FIG. 9 all show embodiments for 
joining to pregiven sealing frames. 
FIGS. 6a to 6d show an embodiment for connecting the cooktop unit 1 to the 
sealing frame 9 by means of a bentover lug 12. The lug 12 of the frame 3 
is connected to the glass-ceramic plate 2 in the embodiment shown in FIGS. 
6a to 6b. 
In the embodiment shown in FIGS. 7a arid 7b, the lug 12 is provided on the 
free leg of the frame 3 not connected to the plate 2. 
In FIG. 8, an assembled cooktop unit 1 is shown which is attached by means 
of a plastic wedge 13; whereas, in FIG. 9, the cooktop unit 1 is connected 
to the sealing frame 9 or built-in cutout 11 by means of a threaded bolt 
14. 
The invention shows a simple and economical way of achieving an effective 
seal between a cooktop unit and a sealing frame or a mounting cutout. The 
seal is defined by a sealing lip which is molded to the silicone flange. 
It is understood that the foregoing description is that of the preferred 
embodiments of the invention and that various changes and modifications 
may be made thereto without departing from the spirit and scope of the 
invention as defined in the appended claims.