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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a panel assembly and is particularly, though not
exclusively, concerned with an assembly comprising a heater and/or cooker
panel adhesively secured to a surrounding frame and/or mounting.
German Gebrauchsmuster Nos. 7401645 and 7406676 disclose cooker hobs
wherein the cooking panel or hob plate is adhesively secured inside a
frame surround by means of a permanently elastic, thermostable adhesive
material. A common feature in these arrangements is that the frame
surround does not overlap the hob plate and that the hob plate is
adhesively secured to an internal flange provided below the hob plate, the
internal flange being provided as an integral part of a continuously
extruded profile from which the frame is formed. The arrangement is such
that the upper surface of the hob plate is either flush with or about 1-2
mm below the exposed upper edge of the frame.
A gap is provided between the sides of the hob plate and the inner surface
of the frame and this is sealed with a permanently elastic sealant. In
practice, arrangements of the above described type have the disadvantage
that they impose restrictions on the choice of material which can be used
in the manufacture of the frame as well as having a relatively narrow
field of practical application. For instance, it is a serious drawback
that only materials which have a surface quality which enables a good,
durable and mechanically firm bond with the adhesive can be used for the
frame part. Since anodized or plastic coated surfaces, for example, tend
to have poor and mostly indifferent adhesion to silicone adhesives, such
materials cannot be used with advantage for making frame surrounds for use
in the above described arrangement because a firm, durable bond cannot be
guaranteed. The same applies to the use of such materials to form mounting
elements used for mounting the hob plate. A further disadvantage of the
above described arrangement is that there is a restricted freedom of
choice with regard to the configuration of the profile for the frame parts
in view of the intended use. For example, while enameled surfaces are very
well suited for adhesive securement by means of permanently elastic
silicone adhesives, it is impractical to enamel edges which have a small
radius of curvature because such edges are highly sensitive to knocks.
Consequently, enameled frames with exposed edges are virtually excluded
from consideration because the enamel tends to chip off very easily at the
curved edges where the radius of the curvature is small, when subject to
blows or knocks.
Lastly, there is also a limit to the ability of plastic profiles or of
plastic-coated metal profiles to withstand thermal stresses. Adhesive
joints can, therefore, be used with frames having such profiles only to a
limited extent where the adhesive joint itself would be subjected to
unduly high temperatures even though these would still be tolerated by the
adhesive itself. Consequently, no plastic frames having such profiles can
be used for high heat resistant applications.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a panel assembly in
which, at least in the visually exposed regions of the frame and/or
mounting elements, there is less restriction with regard to the choice of
material than with the above described arrangements.
According to the present invention, there is provided a panel assembly
comprising a glass or vitreous ceramic panel, a frame having at least two
distinct profiles and/or mounting elements, and a thermostable elastic
adhesive, the profiles and adhesive together forming a coherent unit which
is bonded by a mechanically firm and sealed joint to the panel.
The profiles of the frame can be of the same material or of different
materials and may also be connected together by a number of spot welds or
rivets.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will now be described, by
way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a sectional view of part of one preferred embodiment of a panel
assembly according to the present invention;
FIG. 2 is a sectional view of part of a second embodiment of panel assembly
according to the present invention;
FIG. 3 is a sectional view of part of a third embodiment of panel assembly
according to the present invention;
FIG. 4 is a sectional view of part of a fourth embodiment of panel assembly
according to the present invention;
FIG. 5 is a sectional view of part of a fifth embodiment of panel assembly
according to the present invention; and
FIG. 6 is a sectional view of a sixth embodiment of a panel assembly
according to the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIG. 1 of the drawings, the panel assembly illustrated
therein is for a small or laboratory cooker and comprises a profile 1
which forms an enameled frame which surrounds a glass or vitreous ceramic
hob plate 3. The hob plate 3 is supported on an integral internal flange
of the frame 1. A sharply curved upper edge of the frame 1 is sheathed by
a decorative edge trim 2 formed of alloy steel. The decorative edge trim 2
protects the enameled edge of the frame 1 against knocks and scratches
while having a good chemical resistance. The hob plate 3 is adhesively
secured in the frame profile by means of a permanently elastic,
thermostable adhesive 4 which, when cured, serves to bond the profile 1,
the trim 2 and the hob plate 3 permanently together by a strong and sealed
joint. With the above described embodiment, there is a complete freedom of
color choice for the enameled frame surround while the normally
knock-and-scratch-sensitive upper edge is protected against chipping of
the enamel thereon because of the provision of the edge trim 2.
Referring now to FIG. 2, there is shown a panel assembly which is very
similar to that of FIG. 1 in that the same shaped frame 1 in profile is
provided with internal flange 1a upon which the hob plate 3 rests.
However, in this embodiment, the frame 1 is plastic coated. While this
greatly improves the vulnerability of the sharply curved upper edge of the
profile of frame 1 compared with an enameled profile, it is not possible
to obtain a durable bond between the profile 1 and the hob plate 3 by
means of a silicone adhesive joint. Thus, in this embodiment, the
decorative edge trim 2 of the first-described embodiment is dispensed with
a cover profile 2' is fitted over the flange 1a of the profile 1. This
profile 2' is of generally U-shaped section with one limb shorter than the
other, the flange 1a lying between the two limbs of the profile 2' which
is thereby irremovably secured to the profile 1 after securing by means of
the adhesive 4. The profile 2' is formed of a material, e.g., alloy steel
or aluminum, which is capable of forming a mechanically strong bond with
the adhesive. Thus, the hob plate 3 is firmly secured to the profile 2',
which in turn is firmly and mechanically secured to the flange 1a of the
profile 1. Additionally, the silicone adhesive 4 wets the portions of the
plastics coated profile 1 with which it comes into contact sufficiently to
guarantee a good seal therewith.
Referring now to FIG. 3 of the drawings, there is shown a profile 1' which
is formed of anodized aluminum, which is of a shape to enable the hob
plate 3 to be built into a working surface. A folded portion of the frame
profile extends out laterally to provide a support for the hob plate 3
when it is to be attached to a mantel or other support 5. To make a
durable sealed and strong joint, internal flange 1a of this profile 1 is
covered by a U-shaped profile 2' of alloy steel or aluminum in a similar
manner to that described with reference to FIG. 2. A silicone adhesive 4
is injected into the gap between the hob plate 3 and the profile 1 and the
profile 2'. When the adhesive has cured, the profile 2' is mechanically
firmly and inseparably bonded to the hob panel 3. At the same time, there
is at least an adequate seal between the hob panel 3 and the anodized
profile of the frame 1.
Referring now to FIG. 4 of the drawings, there is shown another form of
frame profile 1", which is of continuously extruded aluminum for a
built-in hob panel 3. In order to improve resistance to scratches, a thin,
suitably shaped alloy steel profile 2" is used to cap the frame profile 1"
in the region of an otherwise visually exposed, upper edge 1b of the frame
profile 1". A silicone adhesvie 4 is injected between an internal mounting
flange 1a of the aluminum profile 1" and the profile 2" as well as between
the upper edge 1b and the profile 2" and between the hob plate 3 and the
flange 1a' and profile 2". As can be seen from FIG. 4, the flange 1a' of
the profile 1" is configurated to define a recess in which one
longitudinal edge of the profile 2" is fitted. When the adhesive 4 has
cured, the profiles 1" and 2" form, together with the adhesive 4, an
indissoluble, mechanically secure and sealed unit which is firmly bonded
to the hob plate 3.
A particular advantage of this embodiment is that it affords an
unrestricted freedom of choice with regard to the aluminum profile 1",
which is of relatively low cost. For example, it may be provided with
integral securing strips or flanges 6 and 7, while the upper edge 1b
thereof which would otherwise suffer knocks and scratches is provided,
without significant additional outlay, with the protective alloy steel
profile 2".
Referring now to FIG. 5 of the drawings, the embodiment illustrated therein
is a highly preferred embodiment because, while being comparatively low
priced, it is extremely adaptable to a wide range of practical
applications. The portion of profile 1"' of frame can be made of alloy
steel, or enameled or plastic coated sheet metal for example. By forming
this part in a deep-drawing operation, it is possible to obtain a fully
closed continuous frame surround without any unsightly welded joints. This
frame can be made of any desired polygonal or round shape. A profile of
the kind illustrated in FIG. 5 is also very easy to produce at low cost
since it requires only very few pressing operations or passes. The frame
profile 1"' has a circumferentially continuous mounting flange 1a"
extending below the marginal portion of the hob plate 3 which is sheathed
by a second profile 2"', which may also be circumferentially continuous or
which may consist of discrete sections. The frame part 2"' is nested over
the inwardly extending flange 1a". Frame part 2"' has a vertical extending
flange or limb 2a which may be provided with stamped formations or
otherwise formed securing elements of any desired shape without requiring
a separate tool for this purpose in the manufacture of the frame profile
1"'. Additionally, with the same profile 1"', the dimension b of the
profile 2"' may be varied so that it is very easy to provide different
dimensions b where this may be required, e.g., for a cover tray. As a
result of this arrangement, it is simple, at only small additional tool
cost, even to mass produce frames of different materials and different
geometrical shape in order to produce a frame unit which is adhesively
fixed by a mechanically strong and sealed bond to the hob plate 3.
Referring now to FIG. 6 of the drawings, a plastic profile 1"", e.g., in
the form of a handle strip or bar, is joined to an aluminum profile 2""
and is connected with a glass or vitreous ceramic hob plate 3 by means of
an adhesive 4. As can be seen from FIG. 6, the adhesive 4 separates the
plastic profile from the plate 3 so that the former remains comparatively
cool despite the high thermal load applied to the adhesive joint in the
region of profile 2"". The adhesive 4 which is forced into the gaps
between the profiles 1"" and 2"" and also between the plate 3 and the
individual profiles 1"" and 2"" securely joins together all three parts to
make a permanent joint when the adhesive has been cured.
The profile in the form of a handle strip or bar may extend completely
around the glass plate 3 or may be a simple cured element.
It is to be appreciated that the present invention is applicable not only
to glass or vitreous ceramic heater panels but is applicable quite
generally to the adhesive securing of any surfaces or panels of such
materials which are subject to thermal loads and stresses, for example,
solar collector cover plates.
It will be apparent to those skilled in the art that many modifications and
variations may be effected without departing from the spirit and scope of
the novel concepts of the present invention.
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