Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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NEW--5 5 6--US
RAPID HEATING GOO~DlZ
FT~T n OF I NV~ vN:
This invention pertains generally to cookware and more
particularly to a cookware vessel in which the cooking surface
5 reaches the desired cooking temperature in the shortest possible
time, which has an increased bottom area available to absorb heat
from a heating source, which maintains its rigidity over a longer
period of time as contrasted to conventional Col.aLLu~ l.ions and,
as a con~eqn~n~ e~ distributes heat more evenly thLvu~ uL the
10 bottom area, and which is more stable with respect to the heat
source during use.
I N I - OF THE lh ~
The great majority of cooking vessels generally have
circular or oval conf igurations which include a bottom and
15 an upwardly extending side wall, though some vessels may have
little or no side wall. However, conventional cookware vessels
invariably have a flat bottom of uniform thickness. Two
undesirable performance characteri6tics of such a typical
construction are that (1) a maximum amount of time is required to
20 bring the cooking surface to the desired cooking t~ cl~u~a and
(2) the vessel 61ides easily when in contact with a 6upport
a~LU~:~UL~ during cooking. The slowness of the cooking surface to
reach cooking t ~ ~ CltUL _ is particularly disadvantageous since
present day .~ rs spend less and less time cooking foods and
25 hence demand that cooking times be as short as possible. The
capacity of conventional vessels to absorb heat is limited by the
area defined by the heat source, usually circular, such as the
area of an electric burner or the heating envelope of a gas
burner. ConVentional vessels also have a tendency to warp,
30 particularly in the larger si2e6, over time due to such factors
as being accidentally permitted to "cook dry"; that is, to be
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kept on a stove in contact with the heat source after the
contents have been removed, or boiled dry.
As a . - ~ee~ e there is a need for a cookware vessel which
heats to cooking temperature quickly, which has an increased
5 capacity to absorb heat from a heat source so as to minimi7e fuel
usage and reduce cooking time, which cannot be slid easily off a
burner or other heat source thereby spilling the cnnt~nt~, and
which retains a nl 1nAl ly flat contour over time, even in the
-- larger sizes and when subject to substantial distorting forces
10 during use.
8~RY OF T~ l~ v ~r~,
The invention is a cookware vessel having a unique multi-
layer bottom ~O~ u~ ~ion which reaches cooking t~ ~tUL~ in
the shortest possible time, increases the quantity of heat
15 applied to the bottom of the vessel as contrasted to a similar
r inAlly sized conventional bottom, distributes the heat more
uniformly in the heat application area, maintains its original
rigidity for a longer period of time as contrasted to
conventional vessels, and has a higher coefficient of friction
20 than conv~nt~n~l vessels whereby the tendency of the vessel to
slide off the heat source due to the normal bumping forces to
which it is aub~ected in use, with - ~ 5C~ spillage of the
contents, is substantially reduced.
The vessel bottom has a series of CU~ ell~LiC circular
25 grooves formed therein which encircle a flat central area. The
grooves are formed so that hot products of combustion can
circulate within the grooves thereby quickly and uniformly
distributing heat throughout the entire heat receiving area of
the bottom. Since a greater bottom surface area i8 eYposed to
30 the heat source due to the greater surface area of the grooves, a
greater surface area than that presented simply by a flat area
with the same peripheral contour is provided and thus more heat
is Ahsorhed by the heat receiving area.
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~ The essence of the invention, however, i8 that the grooves,
both the peaks and the valley6, have only the minimum required
coating thereon 50 that a minimum i - - ~ r ~ to the quick
trAnC" i csinn of heat from the bottom surface to the cooking
5 6urface is provided. Since the groove6 are u U~ LLiC circles
there will always be a plurality of groove edges which will be
perpendicularly, or partially perpendicularly, presented to the
supporting structure, such as a gaE~ burner or an electric coil,
whereby A; Cpl~t ~ of the vessel against the restraining forces
10 provided by the supporting structure is impeded.
Three preferred: _'i Ls are illustrated and described.
All three : ' i - Ls include the grooves described above . The
first preferred: i- L in~ Ao-c an outer coating of porcelain
on the grooves with supplemental friction means applied to the
15 inner f lat central area and outer periphery of the pan . A second
preferred: ' _ i- L includes a pan with an outer polished
surface with no porcelain enamel or supplemental friction
material coating applied thereto. A third preferred: ' i L
inclllA~c~ 8upplemental frictional material applied to the central
20 area and outer peripheral area with the r. inin~ portion o~ the
outer surface of the pan, including the grooves, having a
polished eYterior with no additional coating applied thereto.
The present invention also lends itself to an i ~ d
method of fabricating cookware. The shell is pressed and the
25 bottom grooves Aicc-lcced above are cut into the bottom of the
shell. The shell is then washed with an acid or caustic collltion
to roughen up the surface for the better adherence of coatings.
If a porcelain exterior is to be applied to the outer surface of
the pan, the coating is applied and cured followed by a forced
30 air cooling process. If supplemental frictional material is to
be applied to the central and peripheral areas at the bottom
surface of the pan, the supplemental fric~inn~l material is
applied via a silk screen process followed by an oven curing.
Side decorations may be applied via silk screening prior to the
35 oven curing step. Then, a non-stick coating is applied to the
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interior surface of the pan which i5 then oven cured. The flange
is then trimmed with a lathe or cutting tool. If the outer
surface of the pan includes an exposed metal surface without a
porcelain coating, the exterior i5 then buffed. Then the stud i6
5 welded and torqued onto the sidewall of the pan, the handle i6
attached and then the cookware i8 labeled and packed for
F:h i L .
BRIEP L __AI~ OF T~ n~~
- The invention i5 illustrated more or less dia~L tically
in the ~ ing drawings in which
Figure 1 is a bottom plan view of a cookware vessel of this
invention wit~L parts broken away for clarity;
Figure 2 i6 a sectional view to an enlarged scale taken
subst~nt i :~1 1 y along the line 2 -2 of Figure 1:
Figure 3 is a partial section view to an enlarged scale as
contrasted to Figure 2 of t~Le lower edge of the cookware vessel
of this invention;
Figure 4 is a diagrammatic view of the coating steps in t~Le
process for manufacturing the cookware vessel of this invention;
Figure 5 is a schematic Ley~ese.l~tion of the steps in the
manufacturing process for the cookware vessel illustrated in
Figure l;
Figure 6 is a sectional view to an enlarged scale
illustrating a cookware vessel made in accordance with t~Le
present invention and having a polished metal exterior;
Figure 7 is a schematic LeyLêse.,L-tion of t~Le steps in the
manufacturing process for the cookware vessel illustrated in
Figure 6;
Figure 8 is a sectional view to an enlarged scale
illustrating the cookware vessel made in accordance with the
present invention and having supplemental friction means applied
to the undersurface of the vessel, the ~ ;nin~ exterior surface
o~ the vessel being polished metal; and
Figure 9 is a schematic ~y~esélLl ation of the steps for
manufacturing the cookware vessel illustrated in Figure 8.
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nT~TTT~n L~E:~ nI~lON OF TH~ lh~l~n~lOh
In the following description of the invention, like
reference numerals will be used to refer to like parts from
Figure to Figure in the drawing.
A representative example of the cookware of this invention
i5 indicated generally at 10 in Figures l and 2. In this
instance a frying pan 10 of, for example, about 2~ inches depth
- and about 8 inche6 in diameter has been shown, the pan having a
handle 11, extending outwardly from the vessel for grasping and
10 carrying. Since the handle does not form a part of the invention
it is not further illustrated or described. The sidewall of the
vessel is indicated at 12, the upper end of the circular ~
terminating in an outwardly flared lip, indicated generally
at 13, the underside of which i8 indicated at 14. The lower
15 portion of the sidewall 12 transitions, as at a transition
section indicated generally at 15, into the bottom assembly,
indicated generally at 16.
The bottom assembly 16 i5 ~ormed from metal 17 which is the
base shell of the pan. Preferably the metal is aluminum or an
20 aluminum alloy. The upper, that is, the inner surface 18 of
shell 17, may or may not be coated with one of the conventional
interior coatings such as Te~lon~. In this instance no interior
coating has been shown for purposes of simplicity.
A plurality of grooves, here seven, of which three, 19, 20,
25 21, have been specifically numbered, are formed in the lower,
exterior surface 22 of the bottom assembly. The grooves are
circular, as best seen in Figure l, and have a smooth, sinuous
contour, best seen in Figure 3 but also in Figures 2 and 4.
The bottom assembly also includes a coating 23 which extends
30 from the center of the vessel to at least the area where the
transition section 15 blends into the bottom assembly 16. As
best seen in Figure 3, but also Figure 2, the coating 23 is
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continuous in extent and uniform in thickness throughout the
entire bottom area within the transition section 15. Preferably
the coating 23 is enamel which may be either white or colored.
For aesthetic reasons it may be desirable to provide a rather
5 full bodied color, either, white, black or one of the :~e~ ~Lulu,
for a purpose which will appear hereinafter. Although a
speci~lly developed coating may be employed if desired,
conventional enamels, to the extent they bond well to the coating
next to be described, may be used. Said coating 23 is selected
I0 primarily on its ability to absorb heat quickly; that is, to
transmit heat from a heat source to the cooking surface 18.
Means for providing frictional resistance to the sliding of
the sinuous bottom in use while r ~ i n~ the rapid transfer of
heat from the heat source to the interior cooking surface through
15 the entire grooved area, that i5, the peaks of grooves as well as
the valleys, are illustrated in Figures 2, 3 and 4. The friction
means comprises a circular friction pad 24 placed inside the
grooves 19, 20, 21 on the central, un-grooved area 25, said pad
having a substantial thickness and, preferably, covering the
20 entire central area 25. It will be under6tood that because of
the small ~i P~ of the central 2rea 25 as contracted to the
outside edge of the bottom, a substantial force tending to
tl1 cp~ ;-ce the pan while in contact with a heat source will be
resisted by the width of the friction pad acting in a direction
25 opposed to the displacing force no matter in which direction the
displacing force is applied to the pan. The composition of the
resisting pad is a substance having high friction properties and
the ability to bond to coating 23.
Supplemental friction means are indicated at 26, see Figures
30 3 and 4, which consists of a pad of high friction material lying
outside the grooves 19, 20, 21, in the ungrooved area 27, said
pad having an annular conf iguration . That will be noted that the
friction material lies inside of and outside of the grooves; that
is, it flanks the grooves, so that the peaks and valleys of the
35 grooves contain no additional material, and thus, no impedient to
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the rapid transfer of heat from the heat source to the cooking
surface 18 exists. By maintaining the grooved area 28 free of
any material other than the coating 23, the primary object of
rapid heat transfer through the pan bottom assembly is achieved.
The supplemental friction material 27 may be the same material as
pad 2 4 .
The method of forming the bottom assembly is
diagrammatically illustrated in Flgure 4.
The grooves 19, 20, 21 are formed in such a way that the
stock which initially occupied the cross-sectional area of the
grooves is physically removed. One way to remove the stock or
mass is a lathe cutting process illustrated at 40 in Figure 4.
This has a positive effect on the heat transfer characteristics
of the metal 17, as contrasted to, for example, coining, in that
upward ~ p~ nt of the metal on the food receiving surface 18
(which occurs in a coining operation) is precluded; such upward
displacement results in a change in configuration but no change
in mass of the original metal and hence, a greater mass of metal
must be heated before the cooking surface reaches cooking
temperature. Further, coining re8ult8 in upward ~r
portions of the cooking surface of the vessel which increases
cleaning difficulties as contrasted with the flat sur~ace which
characterizes this invention. There will also be a positive
increase in the rate of heat conductivity through the thin
sections 33 which lie opposite the bases of the grooves 18-20,
see Figure 3, as contrasted to the structure which results from
coining .
After the grooves 19-21 are formed in the metal 17, a
coating of heat-conductive enamel is applied as shown in the
second segment of Figure 4 before the friction material is
applied to a speci~ic portion only of the u.l~lu-~ved bottom
surface 22 by any conventional means, all as best seen in the
third segment of Figure 4. It will be understood that the
friction material 26 may be applied in ring area 27 to cover the
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entire ring area, or in discrete segments, such as are
illustrated at 28, 29 and 30, leaving the spaces 31, 32 between
the segments covered only by the coating 23. The use of discrete
segments may be more advantageous in that a greater number of
5 edges are presented to the supporting surface.
Preferably the colors of coating6 23 on the one hand and 24
and 26 on the other hand are contrasting to present a pleasing
aesthetic appearance to the eye.
-
The grooves 19-21 etc. are circular. As a cnnC~qnpnre a
10 plurality of grooves will always be perp~n~ r to a pan
support structure, such as a gas burner, in all directions of
~ . t of the vessel with respect to the burner. Further, a
plurality of grooves will always be ~liRpoged at an angle less
than perpendicular to a pan support ~~LU~:LULe in all directions
15 of ~ ~, the angularity between the support structure and the
grooves, and the high coefficient of friction between the coating
26 and the pan support structure, creating a resisting force
acting against movement of the vessel across the support
structure. The result will be that the coefficient of friction
20 between the vessel bottom and a support structure will always be
greater than the coefficient of friction between a flat vessel
bottom and the support ~LLU~,~ULC: 80 that the tendency of the
vessel to be displaced from the heat source supporting structure,
and the contents to be spilled, is substantially reduced.
The ~ol~cel.LLic grooves form a series of paths for the flame
or, more accurately, the hot products of combustion, which
results in a uniform distribution of heat over the entire bottom
assembly 16. At the same time, since the area of each groove is
larger than the area which would be present if the vessel shell
were of uniform thickness, a CoLL~ nqly greater surface
area is exposed to the heat source which increases the speed of
cooking and the efficiency of utilization of the caloric value of
the heat source. Since the grooves are formed by the physical
removal of portions of the metal 17, no disruption of the
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21~1622
~ interior surface 18 will be present 50 that smooth, fast cooking
and an ea6y cleaning surface ls provided. At the same time, the
presence of the concentric grooves will impart a rigidity to the
bottom assembly which is greater than the rigidity present in the
typical pan bottom of uniform thickness.
And most importantly, the presence of only a single heat
absorbing coating on the major area of the bottom between ring
area 27 and central section 25 will maximize the speed at which
- heat from the heat source travels through the pan and heats the
cooking surface 18 to the desired cooking t~ ~tUL~, the
absence of any other material in the large annular space between
ring 27 and the central section 25 eliminating any; ~~ to
uick heat transfer from the heat source to the cooking surface
18 .
Figure 5 is a schematic iliustration of the steps for
manufacturing the cooking vessel illustrated in Figures 1
through 4. The shell 10 is pressed from a blank of aluminum or
other suitable metallic material at 41. The plurality of
grooves, i.e. 19, 20, 21 are cut into the bottom 16 o~ the pan 10
at 40 (see also Figure 4). The pan 10 is washed in an acid or
caustic solution at 42 to roughen up the exterior surface of the
- ' A ~ material to improve the adherence of exterior coatings
such as the enamel coating 23 (see Figures 2 and 3). The coating
23 ls applied at 43 with a spraying operation. The pan 10 is
subjected to an infrared curing process at 44 to achieve partial
hardening of the porcelain. Complete hardening is achieved in
the forced air cooling process at 45. The supplemental friction
materials indicated at 26 and 24 (see Flgures 2 and 3) are
applied via a silk screening process at 46. If a decorative
finish is desired, the additional decorative material may be silk
screened onto the sidewall 12 at 47. The coating applied to the
exterior o~ the pan lo is transported through a gas fired oven at
48 to cure the enamel or porcelain 23 and supplemental frictional
material 24, 26. After curing at 48, the non-stick coating is
applied to the interior with a spray process at 49. Again, the
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ve66el 10 is transported through a ga6 fired oven to cure the
interior coating at 50. The flange 13 i5 trimmed with a lathe
process at 51, the stud is attached at 5~, the handle is attached
at 53 and the vessel 10 is labeled and packed at 54.
An alternative embodiment is indicated generally at lOa in
Figure 6. Specifically, the vessel lOa includes no eoating 23 or
supplemental frictional material 24 or 26. The exterior surface
22a i5 a polished metal surface while the interior surface may or
- may not be coated with one of the conventional interior coatings
such as Teflon . The configuration of the grooves is analogous
to those illustrated with respect to Figures 1 through 4. The
vessel lOa has essentially the same heat transfer characteristics
as the vessel 10 illustrated in Figure 1 and, in effect, may
actually transmit heat through the bottom assembly 16a faster
than the bottom assembly 16 of the vessel 10 due to the lack of
any additional coatings applied thereto.
Turning to Figure 7, the process for manufacturing the
vessel lOa is simplified. The vessel is formed at step 41 and
the grooves are cut at step 40 as shown in Figure 5. After the
acid washing at 42 the non-stick coating is applied to the
interior surface 18 at 49, thereby deleting steps 43 through 48
as shown in Figure 5. After the non-stick interior coating is
cured in a gas fired oven at 50 and the flange 13 is trimmed at
51, the exterior surface 22a is buffed at 55 to provide an
aesthetically lrp~Al ;n~ poli6hed appearance. The at~ L of
the handle and packing at 6teps 52 through 54 are essentially the
same as those tl i Ccllc-c~d with respect to Figure 5 .
Turning to Figure 8 and 9, a ve6sel lOb is provided with no
enamel or porcelain coating 23 but with the supplemental
frictional material is provided at 24, 26. Thus, a buffed
metallic pan is provided with frictional material applied to the
bottom assembly 16b. The process for manufacturing the vessel
lOb is illustrated in Figure 9. All of the steps have been
previously discussed with respect to Figures 5 and 7.
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From the foregoing exemplary description it will at once be
apparent to those skilled in the art that various modifications
may be made within the spirit and scope of the invention.
Accordingly it is intended that the sGope of the invention be
5 limited solely by the hereafter ~rr~n~ecl claims when interpreted
in light of the relevant prior art, and not by the ~oregoing
clescription .
