U.S. patent application number 10/612315 was filed with the patent office on 2011-04-21 for heating element accessory having warning device.
Invention is credited to William S. Lerner.
Application Number | 20110088679 10/612315 |
Document ID | / |
Family ID | 43878330 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110088679 |
Kind Code |
A1 |
Lerner; William S. |
April 21, 2011 |
Heating element accessory having warning device
Abstract
Heating element accessories such as a drip pan bowl or a metal
ring surround a heating element and contain a heat warning symbol
from thermochromic ink or epoxy sprayed or otherwise applied
directly to the hot surfaces thereof. For cooking appliances, such
as electric and gas stoves, griddles, grills or their accessories.
The heat warning symbol is distanced from the heating element or
its hottest portions so that the composition can withstand the high
temperature on the surface. In a preferred embodiment the device is
invisible when below the triggering temperature and visible
thereafter. Besides improved cooking appliances, persons can in
certain embodiments update their existing appliances by installing
accessories with the heat warning symbol and avoid replacing entire
heating elements.
Inventors: |
Lerner; William S.; (New
York, NY) |
Family ID: |
43878330 |
Appl. No.: |
10/612315 |
Filed: |
July 2, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10429111 |
May 2, 2003 |
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10612315 |
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Current U.S.
Class: |
126/42 ;
99/357 |
Current CPC
Class: |
A47J 36/24 20130101;
A47J 37/105 20130101; F24C 15/04 20130101; A47J 37/0623 20130101;
A47J 37/108 20130101; H05B 3/746 20130101; H05B 2213/04 20130101;
A47J 37/1271 20130101; A47J 31/58 20130101; A47J 2202/00 20130101;
A47J 27/10 20130101; A47J 27/18 20130101; A47J 37/0786 20130101;
A47J 37/06 20130101; F24C 15/105 20130101 |
Class at
Publication: |
126/42 ;
99/357 |
International
Class: |
F24C 3/12 20060101
F24C003/12 |
Claims
1. An improved metal grate for a gas stove, comprising: a metal
grate having a base that forms a perimeter of the grate and having
a plurality of prongs, each prong protruding from the base and
rising inwardly toward a central flame area, a heat warning symbol
on a surface of the base for warning individuals that the metal
grate is hot, said heat warning symbol comprising: a thermochromic
composition designed to undergo and maintain a readily perceptible
color change whenever and so long as a temperature of the surface
exceeds a predetermined temperature, said color change revealing a
predetermined symbol (which although not directly claimed could be
above or below it or even neither) that communicates that the
surface is dangerously hot, the predetermined symbol readily
visible against a background color of the surface only when and so
long as the temperature of the surface exceeds the predetermined
temperature, the thermochromic composition capable of withstanding
temperatures in excess of approximately 300 degrees Fahrenheit,
having a thickness of less than approximately one sixteenth of an
inch and lacking any covering or overcoat, the metal grate
supporting cooking utensils placed thereon.
2. The metal grate of claim 1, wherein the heat warning symbol is
on an upper surface of the base.
3. The metal grate of claim 1, wherein the thermochromic
composition is ink or epoxy resin.
4. The metal grate of claim 1, wherein a buffer layer is inserted
directly underneath the heat warning symbol, said buffer layer
comprising a thermally conductive adhesive capable of withstanding
a temperature of at least approximately 400 degrees Fahrenheit.
5. The metal grate of claim 1, wherein the heat warning symbol is
the letters "H", "O", "T".
6. An accessory for supporting a heating element on a top surface
of a stove, comprising: a metal bowl having an upper lip and a
substantially hemispheric bowl wall, a heat warning symbol on a
surface of the lip for warning individuals that the accessory,
grate and/or electric coil is hot, said heat warning symbol
comprising: a thermochromic composition designed to undergo and
maintain a readily perceptible color change whenever and so long as
a temperature of the surface exceeds a predetermined temperature,
said color change revealing a predetermined symbol that
communicates that the surface is dangerously hot, the predetermined
symbol readily visible against a background color of the surface
only when and so long as the temperature of the surface exceeds the
predetermined temperature, the thermochromic composition capable of
withstanding temperatures in excess of approximately 300 degrees
Fahrenheit, having a thickness of less than approximately one
sixteenth of an inch and lacking any covering or overcoat, the
accessory for collecting food residue that drips below the heating
element.
7. The accessory of claim 6, wherein the metal bowl rests on a
metal ring that engages a top surface of the stove.
8. The device of claim 6, wherein the thermochromic composition is
ink or epoxy resin.
9. The accessory of claim 6, wherein the bowl wall has a second
lip.
10. The accessory of claim 6, wherein a buffer layer is inserted
directly underneath the heat warning symbol, said buffer layer
comprising a thermally conductive adhesive capable of withstanding
a temperature of at least approximately 400 degrees Fahrenheit.
11. An accessory for supporting a metal bowl that collects food
residue, said metal bowl supporting a heating element, such as an
electric coil a grill or a griddle on a top surface of a stove,
comprising: a metal ring having an upper surface and supporting and
surrounding the metal bowl, the ring engaging a top surface of the
stove so that an outer portion of an upper surface of the metal
ring is visible, a heat warning symbol on the outer portion of the
upper surface of the ring for warning individuals that the heating
element and/or the bowl is hot, said heat warning symbol
comprising: a thermochromic composition designed to undergo and
maintain a readily perceptible color change whenever and so long as
a temperature of the surface exceeds a predetermined temperature,
said color change revealing a predetermined symbol that
communicates that the surface is dangerously hot, the predetermined
symbol readily visible against a background color of the surface
only when and so long as the temperature of the surface exceeds the
predetermined temperature, and the thermochromic composition
capable of withstanding temperatures in excess of 300 degrees
Fahrenheit, having a thickness of less than approximately one
sixteenth of an inch and lacking any covering or overcoat.
12. The accessory of claim 11, wherein the thermochromic
composition is ink or epoxy resin.
13. The accessory of claim 11, wherein a buffer layer is inserted
directly underneath the heat warning symbol, said buffer layer
comprising a thermally conductive adhesive capable of withstanding
a temperature of at least approximately 400 degrees Fahrenheit.
14. An accessory for a gas stove having on its top surface metal
grates of the kind that include a base and a plurality of prongs
protruding from the base and rising inwardly toward a central flame
area, the accessory comprising: a metal ring having an upper
surface and supporting and surrounding a metal grate, the metal
ring resting at least partially on the top surface of the gas stove
a heat warning symbol on the upper surface of the ring for warning
individuals that the accessory and/or metal grate is hot, said heat
warning symbol comprising: a thermochromic composition designed to
undergo and maintain a readily perceptible color change whenever
and so long as a temperature of the surface exceeds a predetermined
temperature, said color change revealing a predetermined symbol
that communicates that the surface is dangerously hot, the
predetermined symbol readily visible against a background color of
the surface only when and so long as the temperature of the surface
exceeds the predetermined temperature, and the thermochromic
composition capable of withstanding temperatures in excess of 300
degrees Fahrenheit, having a thickness of less than approximately
one sixteenth of an inch and lacking any covering or overcoat.
15. The accessory of claim 14, wherein the thermochromic
composition is ink or epoxy resin.
16. The accessory of claim 14, wherein a buffer layer is inserted
directly underneath the heat warning symbol, said buffer layer
comprising a thermally conductive adhesive capable of withstanding
a temperature of at least approximately 400 degrees Fahrenheit
17. An improved grill for heating food safely, comprising: a
plurality of metal bars on which food is exposed to heat, a support
for holding the bars together, a hollow container supporting the
bars and support and containing a heat source, the grill including
an outer perimeter near a conjunction of the hollow container and
the plurality of metal bars, the outer perimeter having a visible
surface, and a heat warning symbol on the visible surface for
warning individuals that the grill is hot, said heat warning symbol
comprising a thermochromic composition designed to undergo and
maintain a readily perceptible color change whenever and so long as
a temperature of the surface exceeds a predetermined temperature,
said color change revealing a predetermined symbol that
communicates that the surface is dangerously hot, and the
thermochromic composition capable of withstanding temperatures in
excess of approximately 300 degrees Fahrenheit, having a thickness
of less than approximately one sixteenth of an inch.
18. The improved grill of claim 17, wherein the thermochromic
composition lacks any covering or overcoat.
19. The improved grill of claim 17, wherein the symbol is readily
visible against a background color of the surface only when and so
long as the temperature of the surface exceeds the predetermined
temperature.
20. The improved grill of claim 17, wherein the thermochromic
composition lacks any covering or overcoat and wherein the symbol
is readily visible against a background color of the surface only
when and so long as the temperature of the surface exceeds the
predetermined temperature.
21. The improved grill of claim 17, wherein the thermochromic
composition is ink or epoxy resin.
22. The improved grill of claim 17, wherein the bars are tubular
and at least two of the bars are substantially parallel.
23. The improved grill of claim 17, wherein the thermochromic
composition has a see-through overcoat for filtering ultra violet
light.
24. The improved grill of claim 17, wherein a buffer layer is
inserted directly underneath the heat warning symbol, said buffer
layer comprising a thermally conductive adhesive capable of
withstanding a temperature of at least approximately 400 degrees
Fahrenheit.
25. The improved grill of claim 24, wherein the adhesive is ceramic
or epoxy adhesive.
26. An improved griddle for heating food safely, comprising: a flat
metal surface on which food is exposed to heat, a source of heat
connected to the flat metal surface, the flat metal surface
including an outer perimeter, said outer perimeter having a visible
surface, and a heat warning symbol on the visible surface for
warning individuals that the griddle is hot, said heat warning
symbol comprising a thermochromic composition designed to undergo
and maintain a readily perceptible color change whenever and so
long as a temperature of the surface exceeds a predetermined
temperature, said color change revealing a predetermined symbol
that communicates that the surface is dangerously hot, the
thermochromic composition capable of withstanding temperatures in
excess of 300 degrees Fahrenheit, having a thickness of less than
approximately one sixteenth of an inch and lacking any covering or
overcoat.
27. The improved griddle of claim 26, wherein the thermochromic
composition lacks any covering or overcoat.
28. The improved griddle of claim 26, wherein the symbol is readily
visible against a background color of the surface only when and so
long as the temperature of the surface exceeds the predetermined
temperature.
29. The improved griddle of claim 26, wherein the thermochromic
composition lacks any covering or overcoat and wherein the symbol
is readily visible against a background color of the surface only
when and so long as the temperature of the surface exceeds the
predetermined temperature.
30. The improved griddle of claim 26, wherein the thermochromic
composition is ink or epoxy resin.
31. An improved griddle for heating food safely, comprising: a flat
metal surface on which food is exposed to heat, a source of heat
connected to the flat metal surface, the flat metal surface
including an outer perimeter, a thin buffer layer of adhesive on
the outer perimeter, the buffer layer having a visible surface, the
buffer layer capable of withstanding a very high temperature
typically reached on the flat metal surface of the improved
griddle, and a heat warning symbol on the visible surface for
warning individuals that the griddle is hot, said heat warning
symbol comprising a thermochromic composition designed to undergo
and maintain a readily perceptible color change whenever and so
long as a temperature of the surface exceeds a predetermined
temperature, said color change revealing a predetermined symbol
that communicates that the surface is dangerously hot, the
thermochromic composition capable of withstanding temperatures in
excess of approximately 300 degrees Fahrenheit and lacking any
covering or overcoat the thermochromic composition and the buffer
layer of epoxy having a combined thickness of less than
approximately one sixteenth of an inch.
32. The improved griddle of claim 31, wherein the adhesive is an
epoxy adhesive or a ceramic adhesive.
33. The improved griddle of claim 31, wherein the thermochromic
composition lacks any covering or overcoat.
34. The improved griddle of claim 31, wherein the symbol is readily
visible against a background color of the surface only when and so
long as the temperature of the surface exceeds the predetermined
temperature.
35. The improved griddle of claim 31, wherein the thermochromic
composition lacks any covering or overcoat and wherein the symbol
is readily visible against a background color of the surface only
when and so long as the temperature of the surface exceeds the
predetermined temperature.
36. The improved griddle of claim 31, wherein the thermochromic
composition is ink or epoxy resin.
Description
PRIORITY INFORMATION
[0001] This patent application is a continuation-in-part patent
application of U. S. patent application Ser. No. 10/429,111
entitled Heat Warning Devices Directly Applicable to Hot Surfaces
filed May 2, 2003 by William S. Lerner, incorporated herein by
reference, of U. S. patent application Ser. No. 09/788,594
previously filed by Applicant and Inventor William S. Lerner on
Feb. 21, 2001 and which is incorporated herein by reference in its
entirety and of U. S. patent application Ser. No. 10/238,348
previously filed by Applicant and inventor William S. Lerner on
Sep. 10, 2002 and which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to safety devices used in
cooking or other activities involving hot surfaces, and in
particular it relates to safety devices applied directly to the hot
surfaces and which alert someone that the surface of a stove or
other appliance or device is too hot to touch.
BACKGROUND OF THE INVENTION
[0003] Applicant's previous applications referred to above and
Applicant's U.S. Pat. No. 6,104,007 to Lerner, incorporated herein
by reference, have explained in detail the need for a heat warning
safety device to notify users that a particular surface remains
hot. As explained, a prime purpose is to warn children in a
household setting of the need not to touch particular surfaces.
Another prime purpose is to warn adults of the same thing.
[0004] Over two million people in the United States suffer burns
due to thermal injuries each year. All you need is one second of
contact at a temperature of 167 degrees Fahrenheit for an adult
(160 degrees Fahrenheit for a child or the lederly) to cause a
burn.
[0005] As previously explained, versatility is an important aspect
of the heat warning safety devices in that they should be
applicable to any surface that can be hot or remain hot.
Accordingly, previous applications by Applicant disclose detachable
heat alert safety devices. However, such devices are subject to the
risk of being tampered with and removed by children. On the other
hand, heat warning safety devices that are built in to the
appliance are not versatile. They cannot easily be applied to any
appropriate surface. Any device by its nature also uses up physical
space since the thermochromic composition has a container and the
container has to be attached to the surface of the appliance by
either a magnet, an adhesive layer or some other attachment
element. Consequently, the heat warning safety device typically
juts out of the surface. That may make the surface bulkier.
[0006] Furthermore, the heat warning safety device that appears on
the surface of an appliance necessarily uses up a certain amount of
visual space. In other words, the surface of an appliance has a
logo on it and possible other information such as instructions. It
is important for appliance manufacturers to allow their logo to
stand out. It is well established principle of writing advertising
copy that having too busy a visual environment makes it difficult
to catch the attention of the viewer to the desired message;
whereas empty visual space near the message draws the viewer's eye
to the message. It is therefore desirable for any heat warning
device to minimize the amount of visual space it uses on the
surface of the appliance.
[0007] In general, moreover, consumers do not want the top surface
of their stoves to be marred by bulky contraptions, even for
safety.
[0008] In addition, while minimizing the visual space used by a
heat warning safety device may be desirable on the hot surface of
an appliance, the countervailing consideration is that children
cannot be expected to know where to look for heat warning without a
conspicuous symbol conveying the heat warning. On the other hand,
since adults could reasonably be expected to be taught to look at a
surface to see whether a heat warning appears on the surface with a
minimized visual prompt, and since children may not be similarly
trainable, there is also a need for a heat warning safety device
that is custom tailored for both children and adults.
[0009] Furthermore, while known heat warning safety devices can be
made to fit a curved or a straight surface, one of such devices
would not be expected to physically fit against both a curved and a
straight surface.
[0010] There is also a need for a heat warning safety device that
can communicate different degrees to which the surface of the
appliance or other object is dangerously hot, i.e., hot versus very
hot.
[0011] One important example of a surface that often gets hot and
stays hot after the source of the heat has been removed and hence
requires a heat warning is the surface of the metal grates that
cover the burners of a gas stove. As noted, the present inventor
has filed other patents on the general subject matter of this
patent application. U.S. Pat. No. 6,104,007 to Lerner discloses
with respect to a gas stove a central metal element having a disk
thereon with a thermochromic composition embedded on the disk as a
heat warning device on the gas stove. At the time of the '007
patent it was thought that the ideal position for the heat warning
device was on such a disk. It was conventional wisdom at that time
that the metal grate itself gets too hot to place a heat warning
symbol made of a thermochromic composition thereon. Thermochromic
compositions that reliably cycle above the maximum temperature that
the metal grates of a gas stove could reach (possibly at least four
hundred degrees Fahrenheit) may not have been easily available at
that time. Since the grate itself can even glow red hot with
intense heat it was thought to be inadvisable to place the heat
warning symbol containing a thermochromic composition on the grate
where the warning symbol could be damaged, could fall off or could
cease to cycle reliably above and below the specified
temperature.
[0012] Furthermore, it was thought that placing a heat warning
device on the metal grate itself could interfere with the heating
process by getting in the way of the placement of utensils on the
grate. This would especially be true if the heat warning device had
significant bulk.
[0013] Notwithstanding the conventional wisdom, the '007 patent's
placement of the heat warning symbol carries certain drawbacks in
relation to the ideal. First, pots and pans that are centered on
the heating element of the gas stove will obstruct the view of the
heat warning symbol. It is commonplace for small pots and pans to
be left on a gas burner after the heat is turned off but where the
metal grates are still dangerously hot. If the cooking utensil is
small relative to the size of the grates, the metal grate will
still be exposed and dangerous to touch.
[0014] A second drawback is that whenever a container is used to
enclose the thermochromic composition the container is made of a
material having a different thermal conductivity than the
composition itself. There is a different thermal coefficient of
expansion between the two materials. Therefore, a space has to be
left between the thermochromic composition and the container. Even
though a covering appears on top of the composition, there is
always the possibility that food or dirt from the stove could enter
the recess between the thermochromic composition. Furthermore,
there is a tiny space between the disk and the central metal
element that the disk sits on. Tiny crevices between the disk and
the central metal element can be receptacles for dirt and food that
accumulates from use of the stove. Thus having the heat warning
device directly in the location of pots and pans dripping with
overflow of food renders the heat warning device susceptible to the
accumulation of food and dirt. This is especially significant today
since stoves are being manufactured smooth and smoother on their
tops nowadays precisely to avoid the accumulation of dirt and grime
on the top surface and make it easier to clean.
[0015] A third drawback is that the heat warning symbol is not
directly on the metal grate, the item that individuals are being
warned against for heat but rather is located on the disk, which is
separate from the metal grates. This is not ideal because the
discrepancy in location means that the temperature of the disk does
not equal the temperature of the metal grates. Hence, the threshold
temperature that triggers the change in color of the thermochromic
composition has to take this into account. In order to take the
difference in temperature into account correctly, the heat warning
symbol has to be in fixed relation to the target surface and the
intervening materials have to be of known heat conductivity.
Furthermore, the discrepancy cannot be too large since to warn
individuals that their cooking surface is too hot to touch, i.e.
115 degrees Fahrenheit, you do not want a heat warning symbol that
will be triggered at a much lower temperature since the ambient
temperature in the room might reach 80 degrees or more. Although
these drawback can be managed, everything else being equal it is
still preferable to have the heat warning device on the same
portion of the equipment that is dangerously hot since the heat
dissipation is not perfectly uniform and predictable and since it
is simpler and more reliable for a thermochromic composition not to
have to calibrate the triggering temperature to take into account
the heat dissipation.
[0016] There is thus a need for a heat warning safety device that
addresses the above concerns and does not require a container to
house it and which can be applied directly to a surface in a simple
manner. Furthermore, there is a need for such a device that
minimizes the amount of visual space that it uses on the
surface.
[0017] In addition, certain appliances, for example a toaster, may
have multiple surfaces that are not all the same degree of
dangerously hot and which would ideally require separate heat
warning devices on each surface. Given that and the fact that as
previously mentioned each such device uses up physical and visual
bulk, it is all the more necessary to have devices or an assembly
of devices that do not use up so much physical and visual
space.
[0018] There is a need for an assembly of heat warning devices that
can be placed on multiple surfaces of an appliance or object having
hot surfaces. There is also a need for such an assembly each of
whose devices has the mentioned advantages of the individual
devices.
[0019] There is also a need for a heat warning safety device that
maximizes the visual impact of the warning it communicates. In
other words, there is a need to maximize the visual disparity
between the appearance of the device when the surface is not
dangerously hot and the appearance of the device when the surface
is dangerously hot and a warning is being communicated.
[0020] In light of the above discussion there is a need for a
device and an assembly of such devices that achieves all of the
above objectives and which is also suitable for temperatures of
target surfaces at least up to a high temperature of a gas oven
(500.degree. F.) since many appliances get that hot and of target
surfaces significantly higher than 500 degrees for such surfaces as
the surfaces of grills and griddles. There is also a need for heat
warning devices in which the thermochromic composition can itself
be directly exposed to and can withstand temperatures of at least
250 to 300 or more degrees Fahrenheit. There is also a need for a
device and an assembly of such devices that is suitable for
temperatures at least 250 to 300 degrees Fahrenheit since
thermochromic compositions that are commonly available are reliably
stable at cycling back and forth at that temperature and certain
surfaces that require a warning device will not get hotter than
that temperature.
[0021] It is believed that no heretofore known product
simultaneously meets these requirements. The present invention
does.
SUMMARY OF THE INVENTION
[0022] The present invention is a heating element accessory such as
a drip pan bowl or a metal ring surround a heating element of a
cooking appliance and contain a heat warning symbol from
thermochromic ink or epoxy sprayed or otherwise applied directly to
the hot surfaces thereof. It applies most readily to cooking
appliances such as electric and gas stoves, griddles, grills or
their accessories. Generally, the heat warning symbol is distanced
from the heating element or its hottest portions so that the
composition can withstand the high temperature on the surface. In a
preferred embodiment the device is invisible when below the
triggering temperature and visible thereafter. Besides improved
cooking appliances, persons can in certain embodiments update their
existing appliances by installing accessories with the heat warning
symbol and avoid replacing entire heating elements.
[0023] Specific embodiments of the present invention include an
improved metal grate for a gas stove, an improved griddle and an
accessory for the electric coil of an electric stove all having
thereon a heat warning symbol comprising thermochromic ink or epoxy
material that is directly applied to a hot surface such as by being
sprayed, stamped, stenciled, silk screened, embossed to the hot
surface of the appliance.
[0024] The most common example of the heat warning symbol is the
letters "HOT". In an alternative embodiment of the appearance of
the heat warning symbol composed of lettering, when cold
(dangerously hot) only the outline of the heat warning symbol is
seen and when hot the full symbol is seen. Generally, the
thermochromic material is shaped in a predetermined symbol or
shape, such as the English letters "HOT" or such letters in another
language, or in the background of such a symbol, communicating to a
viewer that a surface is dangerously hot. Preferably, although not
necessarily, the symbol or its background should lie in the color
range red-orange-yellow, commonly recognized colors of both high
temperature objects and of required caution. Alternatively an
abstract pattern such as alternating wavy lines or a field of
exclamation points, normally invisible and becoming red and black
at a predetermined temperature, can be continued across a front or
back surface of the button, so that portion of the pattern visible
to a viewer on the front side of the button will suffice to convey
the warning.
[0025] In certain instances, a plurality of these symbols may be
used on a single surface to maximize the effectiveness of the
warning system and to tailor the heat alert warning system to both
children, who need guidance as to where to look for said warning
symbols, and to adults, as to whom the impact is greatest when the
warning symbol appears after being invisible.
[0026] The thermochromic composition and device is entirely
constructed out of material able to withstand repeated cycling to a
temperature of a high temperature, in some case approximately 300
degrees Fahrenheit or more, which makes it effective for target
surfaces of 500 degrees Fahrenheit or more, as explained below. The
thermochromic composition is durable enough to withstand rough
treatment, such as dragging a utensil along the heat warning
symbol.
OBJECTS AND ADVANTAGES
[0027] The following important objects and advantages of the
present invention are: [0028] (a) to provide a heat warning safety
device that is versatile enough to be applied to any surface;
[0029] (b) to provide such a device that cannot be tampered with by
children or even by adults; [0030] (c) to provide such a device
that does not use up a significant amount of physical space; [0031]
(d) to provide such a device that does not use up a significant
amount of visual space; [0032] (e) to provide such a device that
can be custom tailored for both children and adults; [0033] (f) to
provide such a device wherein the same device can be applied to
both a straight surface and a curved surface; [0034] (g) to provide
such a device that can communicate differing degrees of dangerously
hot, i.e. differing levels of heat; [0035] (h) to provide such a
device that is easy to apply and easy to manufacture; [0036] (i) to
provide such a device that can withstand high temperatures, i.e.
approximately 250 to 300 degrees Fahrenheit or more if necessary;
[0037] (j) to provide such a device that can function effectively
as heat warning device for target surfaces that experience surface
temperatures of approximately 800 to 1200 degrees Fahrenheit;
[0038] (k) to provide such a device that can form part of an
assembly of such devices covering one or multiple surfaces of a
particular appliance or object; [0039] (l) to provide such a device
that can maximize the visual impact of the heat warning symbol by
maximizing the disparity between the warning symbol when cold and
the symbol when dangerously hot; [0040] (m) to provide a device
that instantly warns anyone including a child that the surface of
an appliance or other hot object is too hot to touch, [0041] (n) to
provide a versatile heat warning device that can be applied to and
used on the widest possible range of surfaces and materials [0042]
(o) to provide a heat warning device that is easy to manufacture
for various kinds of stoves or other appliances, [0043] (p) to
provide a heat warning device for stoves that can be calibrated to
produce a warning symbol only when a certain temperature, such as
115 degrees Fahrenheit, is reached and that can remain in signaling
mode as long as such temperature is exceeded by the appliance
surface, [0044] (q) to provide a heat warning device as above that
makes use of thermochromic compositions that change color when a
certain temperature is reached, such as cholesteric or chiral
nematic liquid crystals or Lucodyes.RTM. designed to change color
when a certain temperature is reached, and [0045] (r) to provide a
heat warning device that is readable by children, [0046] (s) to
provide an improved grate of a gas stove containing at least one
heat warning symbol that is readily visible and effective even when
a particular cooking utensils, such as a pot or pan, is located on
the grate; [0047] (t) to provide an improved metal grate for a gas
stove that blends perfectly into the existing equipment [0048] (u)
to provide an improved metal grate that does not require the
addition of any new parts [0049] (v) to provide an improved metal
grate for a gas stove that is no harder to clean that the existing
metal grates [0050] (w) to provide an improved metal grate that
does not serve as a repository for dirt and grime, [0051] (x) to
provide an accessory for an electric coil for an electric stove
that blends perfectly into the existing equipment; [0052] (y) to
provide an accessory for an electric coil of an electric stove that
is easy to clean; [0053] (z) to provide an improved grill and an
improved griddle that contains at least one heat warning symbols
without serving as a repository for the collection of food and
grime; [0054] (aa) to provide an improved grill that contains at
least one heat warning symbol that blends perfectly into the grill
and likewise to provide an improved griddle containing at least one
heat warning symbol thereon that blends perfectly into the griddle.
[0055] (bb) to provide an improved griddle containing at least one
heat warning symbol that is readily visible and effective even when
a particular cooking utensils, such as a pot or pan, is located on
the griddle; [0056] (cc) to provide an improved grill containing at
least one heat warning symbol that is readily visible and effective
even when a particular cooking utensils, such as a pot or pan, is
located on the grill; [0057] (dd) to provide an accessory for the
heating element of a gas stove containing at least one heat warning
symbol that is readily visible and effective even when a particular
cooking utensils, such as a pot or pan, is located on the heating
element of the gas stove; [0058] (ee) to provide an accessory for
the heating element of an electric stove containing at least one
heat warning symbol that is readily visible and effective even when
a particular cooking utensils, such as a pot or pan, is located on
the heating element of the electric stove;
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] FIG. 1 is an isometric view of the assembly of the present
invention on an unheated toaster.
[0060] FIG. 2 is an isometric view of the assembly of the present
invention on a heated toaster.
[0061] FIG. 3 is a fragmentary plan view of one of the type one
devices of the assembly of the present invention when cold.
[0062] FIG. 4 is a fragmentary plan view of one of the type one
devices of the assembly of the present invention when hot.
[0063] FIG. 5 is a sectional view taken along line 5-5 of FIG.
4.
[0064] FIG. 6 is a fragmentary plan view of one of the type two
devices of the assembly of the present invention when cold.
[0065] FIG. 7 is a fragmentary plan view of one of the type two
devices of the assembly of the present invention when hot.
[0066] FIG. 8 is a sectional view taken along line 8-8 of FIG.
7.
[0067] FIG. 9 is an isometric view of a cup and lid with a
segmented warning symbol in accordance with an alternative
embodiment of the present invention having thermochromic
composition capable of depicting the words "OK", "HOT" and "VERY
HOT" and with the segment "HOT" active both on the lid and on the
cup.
[0068] FIG. 10 is an isometric view of a lid with an alternative
embodiment of a segmented warning symbol in accordance with the
present invention having thermochromic composition capable of
depicting the words "OK" and "HOT" and with the segment "OK"
active.
[0069] FIG. 11A is tri-segmented heat warning symbol for any
surface in accordance with the present invention, and
[0070] FIG. 11B is a bi-segmented heat warning symbol for any
surface in accordance with the present invention.
[0071] FIG. 12 is a top plan view of a heat warning symbol of the
present invention located on the base of a metal grate of a gas
stove.
[0072] FIG. 13 is a top plan view of the accessory of the present
invention surrounding a metal grate of a gas stove.
[0073] FIG. 14 is a sectional view of the accessory shown in FIG.
13.
[0074] FIG. 15 is a top plan view of an accessory of the present
invention surrounding an electric coil heating element with the
drip pan containing the heat warning symbol.
[0075] FIG. 16 is a sectional view of the accessory shown in FIG.
15
[0076] FIG. 17 is a top plan view of an accessory of the present
invention surrounding an electric stove with the symbol on the
metal ring surrounding the drip pan.
[0077] FIG. 18 is a sectional view of the accessory shown FIG.
17.
[0078] FIG. 19 is a top plan view of an accessory of the present
invention surrounding a grill.
[0079] FIG. 20 is a sectional view of the accessory shown in FIG.
19.
[0080] FIG. 20a is a sectional view of an improved outdoor grill of
the present invention with the symbol on the outer perimeter of the
grill.
[0081] FIG. 21 is a top plan view of the apparatus of the present
invention surrounding a griddle with the symbol on the outer
perimeter of the griddle above a buffer layer.
[0082] FIG. 22 is a sectional view of the apparatus shown in FIG.
21
[0083] FIG. 22a is a sectional view of an alternative embodiment
showing the accessory on the metal ring surrounding the drip
pan.
[0084] FIG. 23 is a top plan view of the accessory of the present
invention surrounding a griddle with the symbol on the drip
pan.
[0085] FIG. 24 is a sectional view of the accessory shown in FIG.
23
DETAILED DESCRIPTION OF THE DRAWINGS
[0086] Various embodiments of the invention disclosed in my prior
application of which this application forms a continuation-in-part
and in my prior below-identified U.S. Patent will first be recited
for completeness. Thereafter the specific embodiment which is the
material of this patent will be described.
[0087] The use of a stippling in the drawing figures is intended to
communicate the color red or another conspicuous color different
from the background color of the surface.
[0088] The term "target surface" as used herein refers to the
surface that the individual is being warned may be dangerously
hot.
[0089] The heat alert device of the present invention when used for
the smooth surface of cooktop stoves of either type would comprise
thermochromic composition 32 embedded in the top surface of each
glass area 30, which is the heating element on the smooth cooktop
stove using known methods. For example, the thermochromic
composition 32 may be made in the exact shape of the letters "HOT"
by spraying the composition of thermochromic material 32 over each
glass area 30 after covering the glass area 30 with a cardboard
stencil or other cut-out in the outline or shape of the letters
"HOT". As before, the liquid crystal or thermochromic composition
is designed to turn red and remain red whenever the temperature of
the smooth area of glass exceeds a specified temperature, such as
115 degrees Fahrenheit.
[0090] It should be noted in general that the present invention
makes use of any thermochromic composition that changes color and
remains at that color when a specified temperature is reached or
exceeded--it need not necessarily be cholesteric, although it has
been found that cholesteric liquid crystal material does this
effectively. It is also within the scope of the present invention
to make use of a thermochromic composition that changed color when
it reached a specified temperature or temperature range but changed
to a third color at a higher threshold temperature, so long as the
third color is significantly different from the first
color--although this would certainly not be the ideal kind of
thermochromic composition.
[0091] The ideal heat warning symbol is a color known to represent
warning, such red or orange, although as indicated any color is
contemplated by the present invention.
[0092] It should be understood clearly that the thermochromic
composition of the present invention reveals a predetermined symbol
whenever and so long as the temperature of the surface that the
composition is on exceeds a predetermined temperature. This can be
arranged in more than one way. For example, this can happen as a
result of the thermochromic composition turning color and being
shaped in the shape of the heat warning symbol (or the background
of such symbol). It can also happen as a result of the
thermochromic composition covering the heat warning symbol and then
becoming invisible at the triggering temperature.
[0093] In either case, the thermochromic composition, when the
triggering temperature is reached, simply turns into a color that
makes the symbol readily visible. For example, the thermochromic
composition can turn red at the triggering temperature and be
shaped in the form of the symbol or shaped in the background of the
symbol. The second way is that the thermochromic composition, until
the triggering temperature occurs, blocks the visibility of a red
heat warning symbol underneath it. When the triggering temperature
arrives, the thermochromic composition becomes invisible and
reveals the underlying red symbol.
[0094] In either case, it is preferable that the entire heat
warning symbol and the thermochromic composition be substantially
invisible against a background color of the surface prior to the
triggering temperature being exceeded. This is so that the presence
of the heat warning device be unknown prior to the triggering
temperature being exceeded. This has two advantages: (i) the
warning is more dramatic when it arrives and (ii) the presence of
the warning does not clutter or mar the appearance of the surface
of the stove or other appliance
[0095] In the case where the thermochromic composition covers a
previously written or formed heat warning symbol, preferably, the
heat warning symbol was formed or written underneath the
thermochromic composition by whatever well known processes employ
the least expensive means, such as printing, writing, stamping,
scratching, etc.
[0096] With use of the present invention, when an individual enters
a kitchen that incorporates either a stove or other appliance
having a hot surface, he or she can instantly recognize if any of
the heating elements of the stove or any surfaces of the appliance
are too hot. This is in contrast to the prior art for which the
person would have to first figure out which heating element
corresponds to which light indicator.
[0097] It is to be understood that a heat symbol can take multiple
forms and is not limited to the letters "HOT". The present
invention contemplates that other letters and other letter shapes
besides that of "HOT" could be used as a warning symbol although it
is believed that the simple arrangement of the letters "HOT" in a
bold simple typeset provide the best warning symbol. The symbol may
also take the form of a exclamation point, an international "no"
symbol superimposed a stick diagram of a figure touching a surface,
a stylized human face showing shock or pain, a representation of
flames, or any other recognizable warning symbol. Furthermore, the
present invention also contemplates that the thermochromic
composition in the outline of the letters "HOT" can be embedded in
a surface of a stove, toaster oven or other appliance where the
surface is vertical and perpendicular to the floor, not only
horizontal. In addition, while the drawings depict the
thermochromic composition embedded on the surface of the stove in a
particular configuration and depth, it is contemplated by the
present invention that the depth and configuration of the
thermochromic composition can vary and still be within the scope of
this invention.
[0098] As noted, it is also contemplated by the present invention
that in addition to the thermochromic composition being in an
outline of the heat warning symbol in certain embodiments, such as
in the shape of the letters "HOT", the thermochromic composition
could instead be in the background of such an outline. By this is
meant that the thermochromic composition would form the entire area
except an outline of the letters "HOT".
[0099] The point of one feature of the present invention is to use
the thermochromic composition to create a color contrast between a
color such as red or some other color in order to depict the
letters "HOT" in red or that color whether by virtue of the
thermochromic composition itself being the letters "HOT" or whether
the thermochromic composition surrounds the letters and in effect
constitutes everything else except the letters "HOT" or whether the
thermochromic composition covers a previously inscribed symbol and
becomes invisible to reveal such symbol at the triggering
temperature.
[0100] Furthermore, it should be noted that in this patent
application, the term "red" refers to all possible variations and
shades of the color red as well as to all possible variations of
the colors orange and yellow. Red and orange and yellow are the
colors associated with heat. Furthermore, if the hot surface (as
opposed to the area of the thermochromic composition) itself is or
becomes red when hot, then the thermochromic composition would have
to be orange and vice versa.
[0101] The term "appliance" is a broad term that encompasses .any
appliance and any object that has a hot surface. Many appliances
have curved surfaces and the present invention can be applied
directly to such surfaces, which further maximizes the viewing
angle of the warning. The hot surfaces are typically metal or glass
but can be of other suitable materials such as philonic.
[0102] With respect to thermochromic compositions referred to
herein for the claimed embodiments, it is believed that the desired
thickness of the ink or epoxy composition is approximately 2 mils.
So for example, if the application process used in order to
directly apply the ink or epoxy thermochromic composition to the
surface is the silkscreening process, it is believed that employing
a single pass or multiple passes using a 70 to 80 course screen
would result in 2 mils of thickness of ink or epoxy.
[0103] The present invention is described in various embodiments in
which a heat warning symbol is applied on a particular surface. It
is of course possible and indeed necessary that more than one such
heat warning symbol be applied to certain surfaces. That can occur
for several reasons. The surface may be approached from several
directions or there needs to be multiple symbols to increase the
strength of the warning since the symbol needs to be small given
the thinness of the surface the symbol is applied to. Accordingly,
For example, where an improved grate, grill, griddle or an
accessory for an electric stove is described in this patent
application as having a heat warning symbol positioned on its
surface, it should be understood that several such heat warning
symbols can and in some cases should be placed on such surface in
accordance with the present invention.
[0104] Two or more sides or walls of an appliance can sometimes get
hot and the one side might not be suitable to have a heat alert
safety device attached to it even though the same heat alert safety
device of the present invention is made specifically for the other
side of the same appliance. This application is especially useful
for kitchen workers surrounded by multiple ovens and/or hot
counters--they can place the device on each such hot surface. Other
surfaces that get hot and to which device can be usefully applied
besides food related appliances include radiator caps located under
the hood of a car or other vehicle, piping through which hot steam
flows, the surface of a curling iron, surfaces of a steam press and
many others listed herein in the Objects and Advantages.
[0105] The apparatus of the present invention will now be
illustrated by reference to the accompanying drawings. A single
heat warning safety device in accordance with the present invention
has been assigned reference numeral 10. An assembly of such devices
has been assigned reference numeral 100. Other elements have been
assigned the reference numerals referred to below.
[0106] The present invention is designed to provide an overall
system for heat warning safety devices that maximizes the
effectiveness of the warnings. Although FIGS. 1 through 8 depict
the assembly of heat warning devices applied to an ordinary
toaster, it will be appreciated that the assembly and individual
devices of the present invention are equally suitable for
application to any surface that can become hot
[0107] As seen from FIGS. 1-8, heat warning safety device 10 is
attachable to a surface of a toaster to warning individuals that
the surfaces of the toaster is or are hot. Device 10 comprises
thermochromic composition 20 shaped in a predetermined symbol or in
the background of such symbol which communicates that the surface
is dangerously hot, the symbol substantially invisible against a
background color of surface 30 and designed to undergo and maintain
a readily perceptible color change so that the symbol 20 is readily
visible against said background color 30 whenever and so long as
the temperature of the surface 30 exceeds a predetermined
temperature.
[0108] Thermochromic composition 20 does not require a container to
house it and does not require an overcoat of another substance to
cover it or contain it. It is applied directly to the surface and
allowed to dry and remain on the surface without the need for a
covering or cured with a UV dryer.
[0109] FIG. 1 is intended to show the placement of the heat warning
safety devices on an appliance such as a toaster. FIG. 1 shows the
device 10 on a front for a first surface 30A, a top t or second
surface 30B and a side s or additional surface 30C of toaster 40.
These can also be called a first surface, a second surface and a
third surface. Alternatively, FIG. 1 could been example of a
toaster having three type one 10A devices 10 when cold, as
explained below.
[0110] As seen in FIG. 2, there are two versions of the device 10,
which can be referred to as a first type 10A and a second type 10B.
As seen in FIG. 3, which appears blank, (and in the leftmost
surface of FIG. 2) the first type 10A of device 10 is basically
invisible or faintly visible when the device 10 is "off", i.e. when
the surface to which it is attached is cold. The term "cold" here
simply means not dangerously hot as that term is defined.
Dangerously hot typically although not necessarily may be 115
degrees Fahrenheit. The reason first type 10A is invisible is
simply that the color of the thermochromic composition 20 is
designed to be the same as the background color on the first
surface 30A of the toaster 40 whenever the surface temperature does
not exceed the specified temperature that would trigger the heat
warning symbol to be activated. As seen in FIG. 4 and the front
surface of FIG. 2, when the first surface 30A of the toaster 40
reaches the specified temperature, which may be 115 degrees
Fahrenheit, first type 10A of device is activated so that the heat
warning symbol, which in FIGS. 1-8 happens to be the letters "HOT",
turns red or some other noticeable color.
[0111] The first type 10A of device 10 is thus most suited for
warning adults. A child cannot be expected to know where to look
for a warning device. An adult, in contrast, can be taught to get
used to the idea that a particular area of a surface is capable of
changing color to communicate a warning and therefore one needs to
look there to see if it is hot. The advantage of first type 10A of
device 10 is that the visual change from invisible to conspicuous
has a greater impact than a change from one color to a different
color. Furthermore, by being invisible except when first surface
30A is dangerously hot, the logo of the manufacturer is not
visually obstructed by additional information (i.e. the warning
symbol) in a tight space that can only hold just so much visual
information. This feature appeals to the manufacturer of the
appliance.
[0112] The second type 10B of device 10 is illustrated in FIGS. 6
and 7 as well as the top or second surface 30B of FIG. 2. As seen
in FIG. 6 and the second surface 30B of the toaster 40 in FIG. 2,
when cold (not dangerously hot), the second type 10B of device 10
is invisible or faintly visible except for the outline of the heat
warning symbol, which in this case is the letters "HOT". In other
words, a remainder of the heat warning symbol of the second type
10B of device 10 is invisible or faintly visible and only the
outline of the symbol is clearly visible. This is accomplished by
having the outline 20A of the symbol being a permanent marking of a
color different than the background color of the surface of the
appliance whereas the remainder 20B of the symbol is a
thermochromic composition 20B that is identical to the background
color of the surface of the appliance (and which becomes red or
another color different from the background color upon reaching a
specified temperature).
[0113] This second type 10B of device 10 is most suited for warning
children as to whom an invisible symbol when cold would not prompt
or teach the child where to look for a warning. On the other hand,
by limiting the visual portion to the outline, the visual space
used by type two 10B of device 10 is minimized. By having both
types of the device 10, an assembly 100 is custom tailored to all
ages of individuals. As seen in FIG. 7, when the second surface 30B
of the toaster 40 reaches the specified temperature, which may be
115 degrees Fahrenheit, second type 10B of device 10 is activated
so that the heat warning symbol, which in FIGS. 1-8 happens to be
the letters "HOT", turns red or some other noticeable color.
[0114] It will be understood that the various embodiments and
methods of attachment may be combined.
[0115] When the thermochromic composition is applied by being
sprayed, printed, stenciled, embossed, stamped, silk screened or
otherwise applied to the surface 30, the composition 20 is
typically applied initially in a liquid or in a malleable solid
form. Only then it dries or dries instantly. Accordingly,
thermochromic composition 20 is capable of being applied as a
liquid directly to the surface 30 in the predetermined shape and it
is capable of remaining on surface 30 in its predetermined shape in
solid form. It is capable of withstanding temperatures in excess of
300 degrees Fahrenheit.
[0116] It should be noted that thermochromic ink and epoxy
compositions that withstand temperatures of at least approximately
250 degrees to 300 degrees Fahrenheit are commonly available.
Although specialized thermochromic ink and epoxy compositions that
withstand higher temperatures, such as 500 degrees Fahrenheit, are
also known and available, such specialized thermochromic
compositions should only be used if they are necessary. If such
specialized compositions are not needed for a particular
application, it is preferable to use the more commonly available
compositions that only withstand temperatures of up to 300 degrees
Fahrenheit. Accordingly, in applying the present invention to
various kinds of surfaces, a determination should be made whether
the surface is likely to require the more specialized ink and epoxy
thermochromic ink and epoxy composition or the more commonly
available thermochromic ink and epoxy composition.
[0117] Certain surfaces that require a heat warning safety device
do not become hotter than 300 degrees Fahrenheit. One reason for
this is that it is useful to place the heat warning safety device
10 of the present invention on outer housing surfaces of grills or
other appliances in addition to the areas closer to the heating
elements. While the heating element itself and the areas
immediately proximate to it may well exceed 300 degrees Fahrenheit,
the area on the housing of a grill or other appliance is not likely
to exceed a temperature of 300 degrees Fahrenheit under normal use.
Accordingly, for these application the device 10 of the present
invention employs a thermochromic ink or epoxy composition suitable
for surfaces that are not likely to exceed a temperature of 300
degrees Fahrenheit.
[0118] As best seen in FIG. 5 and FIG. 8, thermochromic composition
20 is very thin. It has the thickness of written ink printed,
embossed, sprayed or otherwise applied to a smooth surface.
[0119] For example, a smooth surface of an appliance may have
embossed thereon a particular logo or product name. If an
individual were to close his eyes and feel that surface they would
be able to feel the raised ink but only barely. Accordingly, the
thickness in solid form of thermochromic composition 20 is such
that the thermochromic composition is either faintly visible or
invisible when viewed from a line of light tangent to the surface
30 by someone whose attention is not specifically directed to said
thermochromic composition. Although FIGS. 5 and 8 do show a visible
surface, that is simply to illustrate the fact that there is at
least some thickness and is not intended to be to scale.
[0120] As noted, typically, composition 20 is applied as a liquid
directly to the surface by being printed, sprayed, stamped,
stenciled, embossed or silk screened onto said surface.
Thermochromic compositions that are suitable are well known and
include inks and epoxy resins. For example, the following are
examples of thermochromic compositions made by various companies
that are applicable to the present invention. Hallcrest, Inc.makes
color change products that are temperature sensitive. For example,
Hallcrest, Inc. manufactures microencapsulated thermochromic liquid
crystal slurries and sprayable microencapsulated thermochromic
liquid crystal coatings and Lucodyes.RTM.. Chromatic Technologies,
Inc. manufacturers Dynacolor.RTM. Resin for epoxy screen ink.
Matsui International Company, Inc. manufacturers a product called
Chromicolor.RTM. which is an epoxy resin.
[0121] The present invention in the patent application is
specifically geared to accessories 100 surrounding hot cooking
surfaces containing heat warning symbols 21 and to improved cooking
devices containing such heat warning symbols. In both cases, these
are surfaces that would benefit from a heat warning accessory or
device that does not constitute a bulky intrusion since such an
intrusion would interfere with the proper functioning of the device
having the surface or would disturb the functioning of a device
near said surface. Furthermore, the following discussion, which
discusses various accessories for cooking appliances and various
improved cooking devices, focuses specifically on such accessories
and devices that have surfaces that often get hot and remain hot
after the heat source is removed and which do not permit the
application of a heat warning device that carries a significant
amount of bulk. In accordance with the concepts of the present
invention, the heat warning symbol 21 has been applied directly to
the relevant surface in a preferred embodiment without a covering
or container and such direct application has occurred using any of
various well-known means described herein, e.g. spraying, printing,
embossing, stamping, silkscreening, etc. However, as seen in FIG.
14a, it is also contemplated that by the present invention that in
some case a see-through covering 199 or glazed on surface may be
added over the thermochromic composition provided that the total
thickness of the heat warning symbol plus the covering does not
render it too bulky. In a preferred embodiment, the entire symbol
and any covering would be approximately one sixteenth of an inch or
less. Alternatively, the heat warning symbol could be embedded in
the surface so that the top of any covering over the heat warning
symbol is smooth with the nearby surface. In any case, the heat
warning symbol together with any covering would not protrude out of
a surface so much that it would appear to be a bulky intrusion on
the surface.
[0122] The thickness of the thermochromic composition 20 is less
than approximately one sixteenth of an inch in order to minimize
the interference with the proper functioning of the accessory that
they are on and with the proper functioning of the nearby heating
elements of the stove. In a preferred embodiment, the thickness is
so small that it is invisible or only faintly visible when looked
at from the side of the surface parallel to the surface. For
example, the thickness may be less than approximately one sixty
fourths of an inch, certainly less than one sixteenth of an inch.
Preferably, the thermochromic composition 20 is either faintly
visible or invisible when viewed from a line of sight tangent to
the first surface by someone whose attention is not specifically
directed to the thermochromic composition. It is believed that the
desired thickness of the ink or epoxy thermochromic composition for
effectively making use of the heat warning symbol of the present
invention is approximately 2 mils, which is understood to be 2/1000
of an inch.
[0123] One important example of a surface that often gets hot and
stays hot after the source of the heat has been removed and hence
requires a heat warning is the surface of the metal grates that
cover the burners of a gas stove.
[0124] As previously noted, it is counter-intuitive to place the
heat warning symbol directly on the metal grates. Nonetheless, in
one preferred embodiment, the present invention does place the heat
warning symbol at a certain part of these grates in part to have
the have the heat warning device on the same item as the item being
warned could be dangerously hot. This assures receiving the best
reading of the temperature of the grate in the simplest way.
Further, the symbol is so thin it does not mar the appearance of
the stove's burner. The symbol (when color-activated by the
threshold temperature) will be visible in the preferred embodiment
even when pots and pans remain on the burner of the gas stove. The
symbol is applied directly to the surface so it does not require
that there be an additional piece of equipment that attaches to the
thermochromic composition or to the surface of the grate. This
avoids having crevices that could catch dirt or food are avoided.
The heat warning symbol simply blends beautifully into the existing
metal grates of the gas stove.
[0125] In particular, the top visible surfaces of the base or
perimeter of the metal grates are a favorable location to warn
individuals that the metal grates of the gas stove are dangerously
hot. In one preferred embodiment, the visible top surfaces of the
base of the metal grates is used to position a heat warning symbol
in accordance with the present invention. The prongs of the metal
grate themselves support the pots and pans resting on the grate. So
the present invention avoids positioning the heat warning symbol on
the top surfaces of the prongs themselves--these surfaces endure
significant rubbing action from the placement, shifting and removal
of cooking appliances thereon. The present invention thus maintains
the durability of the heat warning symbol and avoids allowing its
effectiveness to be impaired or destroyed. The heat warning symbol
is positioned on the visible surfaces of the base of the grates
since the base is configured to be lower in height than the prong's
top surface on which the pots and pans rest. The base of the grates
form the perimeter of the grates. Accordingly, the base of the
grates is an excellent place to position a heat warning symbol. It
is visible to the user of the stove. It is located at the edge of
the potentially hot surface so the user's hand would typically
cross the perimeter before putting the hand on the grates and the
user would see the heat warning symbol before touching the hot
metal grate. Also, a warning symbol on the base would not be
affected by moving and removing pots and pans on the grates.
[0126] Furthermore, since the base of the grate is lower than the
far ends of the prongs which glow red hot at times, the base is
cooler than the hottest portion of the grate. This distance in
space and the resulting temperature differential permits a
thermochromic composition to be durable and effective on the base.
Yet since the thermochromic composition would still be separated
from the hottest portions of the prongs of the grate only by
intervening metal of the same grate, the triggering temperature of
the thermochromic composition on the base can still effectively be
calibrated to take into consideration the temperature on the
remaining surface of the grate.
[0127] As seen in FIG. 12, the heat warning symbol made of
thermochromic composition 20 is located on a surface of base 96
which is at the outer perimeter of a metal grate 99 which is the
heating element of a gas stove. Base 96 often has a flat upper
surface that is approximately one half inch to three quarters of an
inch wide and that accommodate the heat warning symbol 21.
[0128] Accordingly, the present invention contemplates an improved
metal grate for a gas stove comprising a metal grate 99 having a
base 96 that forms a perimeter of the grate 99 and having a
plurality of prongs, each prong 97 protruding from the base and
rising inwardly toward a central flame area
[0129] The improved metal grate also includes a heat warning symbol
(or multiple heat warning symbols) on a surface of the base for
warning individuals that the grate is hot. The heat warning symbol
comprises a thermochromic composition shaped in a predetermined
symbol or in the background of said symbol which communicates that
the surface is dangerously hot, the symbol designed to undergo and
maintain a readily perceptible color change whenever and so long as
the temperature of the surface exceeds a predetermined temperature.
The thermochromic composition is capable of withstanding high
temperatures. In a preferred embodiment, the thermochromic
composition is capable of withstanding temperatures in excess of
approximately 300 degrees Fahrenheit. The heat warning symbol has a
thickness of less than approximately one sixteenth of an inch.
preferably, the heat warning symbol lacks any covering or overcoat
since it is applied directly to the surface of the grate by any of
the means described in this patent application such as spraying,
embossing, stamping, printing, silkscreening, etc. The metal grate
supports cooking utensils placed thereon In a preferred embodiment,
the thermochromic composition would be substantially invisible
against a background color of the surface of the base and would
become readily visible against that background color or would
reveal a heat symbol that is readily visible against that
background color whenever and so long as the specified temperature
is reached.
[0130] The heat warning symbols could be positioned conspicuously
along the perimeter of the grate in a manner readily visible and
understandable to a user standing in front of the stove. By
"understandable" is meant that is for example the heat warning
symbol consists of lettering, at least one instance of the
lettering will be facing the viewer standing in front of the stove.
If the stove is on an island whereby it can be approached in all
four directions, each direction could have a heat warning symbol
facing a person approaching the stove in that direction. This best
illustrated in FIG. 12.
[0131] In this embodiment, and similarly in the other embodiments
that follow, the thermochromic composition itself need not
withstand one particular level of heat but could be capable of
withstanding other levels of heat. Furthermore, the thermochromic
composition could be positioned at varying distances from the
target surface so as to be useful for warning against heat on
target surfaces that experience heat levels from 250 degrees up to
approximately 800 to 1200 degrees Fahrenheit, depending on the
target surface.
[0132] In an alternative preferred embodiment, a ring of metal or
other heat conducting material is positioned surrounding each metal
grate of the burner of the gas stove. This would allow the heat
warning symbol to be positioned on a top visible surface of the
metal ring surrounding the grate rather than on the grate itself.
Accordingly, individuals could update their existing gas stove by
adding metal rings around the grates where the rings themselves
would have heat warning symbols on one of more of their surfaces.
These individuals would thus not have to replace their existing
metal grates for each burner of the gas stove in order to install
warning symbols on the grates for each burner area. Rather they
could just purchase the metal rings that contain heat warning
symbols. Such rings would be less expensive than the metal grates.
Furthermore, the heat warning symbol would not be affected by
friction on the metal grates from movement of the pots and pans
resting thereon. Although the metal rings would cool off sooner
than the metal grates given that they are further from the flame
area in the center of the grates, this would be taken into
consideration. Accordingly, in a preferred version of this
embodiment, the thermochromic composition making up the heat
warning symbol on the rings would be calibrated so as to warn of
dangerous heat whenever the temperature of the metal grate was too
hot.
[0133] Another important type of surface that often gets hot and
stays hot after the source of the heat has been removed and hence
requires a heat warning is the surface of the insulated serpentine
electric coil heating element which coil typically sits on a grate
on the top surface of the electric stove. Typically these electric
coils sit on a drip pan, which is a metal bowl designed to collect
food residue that drips under a heating element such as the
electric coil. It is believed that this is the case with the
electric range made by or for GE.RTM.. As best seen in FIGS. 16,
18, 20, and as is often the case, the drip pan is held up by a
metal ring that engages the top surface 103 of the stove and
prevents the drip pan from falling through the opening in each
burner. The metal bowl or drip pan typically has an upper lip.
Typically, that upper lip of the drip pan covers most of the width
of the upper surface of the metal ring but some portion remains
visible.
[0134] Accordingly, individuals could update their existing
electric stove by adding metal rings around each electric coil and
the rings themselves would have heat warning symbols on the outer
portion of the upper surface. Alternatively, they could update
their electric stove by replacing the drip pan with a drip pan
having the heat warning symbol on its upper lip. In either case,
these individuals would thus not have to replace their existing
electric coils for each heating element of the electric stove in
order to install warning symbols on the stove. For a four heating
element electric stove, the cost of four new electric coils could
be approximately $80. The cost of either four metal rings or drip
pans having warning symbols thereon would be expected to be well
below a fourth of that cost. Thus the individuals could just
purchase the metal rings or the drip pans that contain heat warning
symbols and improve the safety of their stove. In this regard, it
is noted that people do like to routinely replace their drip pans
and metal rings (Trim Rings.RTM.) for cosmetic reasons.
[0135] In this way, the heat warning symbol would not be adversely
affected by friction caused by movement of the pots and pans on the
electric coil whereas if the heat warning symbol were on the disk
in the center of the electric coil roughly at the height of the
coil itself the warning symbol could be so adversely affected.
Furthermore, the heat warning symbol of the present invention is
not vulnerable to the collection of dirt and grime in crevices
found between one part of the heat warning device and another or
between the heat warning device and the surrounding surface it is
on. Although placing the heat warning symbol on the drip pan or
metal ring would be imperfect since the metal ring or drip pan
would cool down to below the too hot to touch temperature (for
example, 115 degrees Fahrenheit) much sooner than the electric
coil, this would be taken into consideration. Accordingly, in a
preferred version of this embodiment, the thermochromic composition
making up the heat warning symbol on the rings could be calibrated
so as to warn of dangerous heat whenever the temperature of the
actual coil was too hot.
[0136] It is noted that in any embodiment, whenever the heat
warning symbol is not on the actual "target surface" being warned
against for heat (the improved metal grate with the symbol on the
base of the grate not being an example of such an embodiment) the
heat warning symbol must be in a fixed relation thereto. There
would be almost no point in calibrating the heat dissipation
between a metal ring and an electric coil if the metal ring could
be moved even a quarter of an inch, which could occur if the metal
ring were not spatially fixed with respect to the electric coil.
Another requirement is that between the heat warning symbol and the
target surface there are materials whose heat conductivity is
clearly defined and measurable. An additional requirement is that
the discrepancy in temperature between the target surface and the
heat warning symbol not be too great, as explained above.
[0137] In accordance with one embodiment of the present invention,
a metal ring that holds up the drip pan is sold under the brand
name Trim Ring.RTM. by a company called Range Kleen. The metal
ring's upper surface has an outer annular portion that in certain
embodiments is partially visible to a user of the electric stove
even when the drip pan is inserted thereon. This metal ring would
surround the serpentine electric coil or other heating element and
would rest at least partially on the top surface of the electric
stove. In accordance with the present invention, a heat warning
symbol would be located on the visible outer annular portion of the
upper surface of the metal ring. The symbol warns that the ring is
hot and by implication that the electric coil heating element
and/or drip pan is hot. The heat warning symbol on the surface of
the outer annular portion of the ring would be a thermochromic
composition shaped in a predetermined symbol or in the background
of said symbol which communicates that the surface is dangerously
hot, the symbol designed to undergo and maintain a readily
perceptible color change whenever and so long as the temperature of
the surface exceeds a predetermined temperature. The thermochromic
composition would be capable of withstanding temperatures in excess
of approximately 300 degrees Fahrenheit. The thermochromic
composition would not be bulky and in a preferred embodiment would
having a thickness of less than approximately one sixteenth of an
inch and lacking any covering or overcoat. In a preferred
embodiment, the thermochromic composition would be substantially
invisible against a background color of the outer portion of the
upper surface of the metal ring and would become readily visible
against that background color or would reveal a heat symbol that is
readily visible against that background color whenever and so long
as the specified temperature is reached.
[0138] Accordingly, in embodiments in which the heat warning symbol
appears on the surface of the metal ring, as seen from the
drawings, this metal ring is in fixed relation to the electric coil
or other heating element, which is the primary target surface. This
may be accomplished by the fact that the metal ring engages the
edge of the recess in the burner area of the stove into which are
placed, in the example of an electric heating element, the electric
coil, its support grate and the metal bowl. Other ways may easily
be imagined of ensuring this fixed relation between the accessory
containing the heat warning symbol, i.e. the metal ring or drip
pan, and the target surface such as the surface of the heating
element or surrounding accessories and surfaces.
[0139] As noted, a further important surface that often gets hot
and stays hot after the source of the heat has been removed and
hence requires a heat warning is the surface of another accessory
called a drip pan (referred to above) that in the case of an
electric stove supports a grate and the insulated serpentine
electric coil heating element on the grate on the top surface of
the electric stove. The accessory is essential a metal bowl having
an upper lip and a substantially hemispheric bowl wall.
[0140] The upper lip of the drip pan typically sits on a metal ring
as described above, which metal ring engages a substantially smooth
surface of a top of the electric or other stove. The entire heating
element and drip pan is usually situated in one of four (or other
number of) recesses in the top surface of the stove. One or more
heat warning symbols as previously described and in accordance with
the present invention would be positioned on a surface of the upper
lip of the drip pan for warning individuals that the metal bowl,
electric coil and/or metal ring is hot. The surface of the upper
lip would be visible to users of the electric stove when the bowl
is fixed in position supporting the electric coil and grate. As
noted, the bowl is used primarily for collecting food residue that
drips beneath the heating element. In certain embodiments the bowl
wall has a second lip along the bowl wall.
[0141] Another surface that gets very hot and remains hot even
after the heat source is turned off and which would not accommodate
a very bulky heat warning device is the surface of an indoor or
outdoor grill, for example a barbecue grill. In the case of an
outdoor grill, an improved grill of the present invention would
include a plurality of parallel metal tubular bars on which food is
exposed to heat, a support, such as one or more crossbars, for
holding the bars together, and a hollow container for supporting
the bars (with its support). The hollow container also contains a
heating element. The heating element can be an electric heating
element or hot "burning" charcoals, or another suitable heat
source. It should be understood that the bars are typically
parallel or substantially parallel but they need not be.
"Substantially parallel" as used herein means that two bars, if
extended indefinitely, would meet at an angle of between 140 and
180 degrees of each other. Furthermore, it should be understood
that the bars are typically tubular but need not be. The basis idea
of this embodiment of the present invention is a grill having a
heat warning symbol thereon made of a thermochromic composition in
the shape of a warning symbol. It should also be understood that
the word "hollow" in the phrase "hollow container" merely means
that the container contain some free area in which the heating
element is placed. The lower area of the bars and any support
either descends somewhat into the hollow container or else rests on
an upper edge thereof. FIGS. 19-20 depict an indoor grill showing
the bars somewhat thicker than they might ben--but this is merely
illustrative and one example. FIG. 20a shows a fragmentary view of
an outdoor grill where a hollow container 150 is supporting the
bars 130 and support, rather than a drip pan. Symbol 21 made of
composition 20 is directly on an outer perimeter 166 of the grill
atop container 150. It should be appreciated that while FIG. 20a
depicts outer perimeter 166 in one particular configuration
projecting outward, numerous other configurations of outer
perimeter 166 would also be within the scope of the present
invention. Heating element 170 is somewhere in the container of the
outdoor grill. The heating element 170 for the indoor grill can be
in any suitable place below the bars 130. In FIG. 20 metal ring 300
engages top of stove 119.
[0142] As seen from FIGS. 19 and 21, whenever the stove has
multiple burners, for example four of them, the symbol 21 is
positioned so that it faces the user from any direction he or she
approaches the stove. Note however that the grill in FIG. 19 and
the griddle in FIG. 21 can be said to represent the southwestern
corner of a stove top and that therefore there are two symbols that
have the heat symbol facing in both directions since in each of
these cases that symbol can forewarn against an approach of a hand
both from across an adjacent burner as well as from across the
actual burner that the symbol is on.
[0143] The grill includes an outer perimeter having a visible
surface. On the visible surface are one or more heat warning symbol
made of a thermochromic composition shaped in a predetermined
symbol or in the background of said symbol which communicates that
the surface is dangerously hot, the symbol designed to undergo and
maintain a readily perceptible color change whenever and so long as
the temperature of the surface exceeds a predetermined temperature.
The symbol(s) warn that the grill is hot. The thermochromic
composition is capable of withstanding temperatures in excess of
approximately 300 degrees Fahrenheit and would not be bulky. For
example, the heat warning symbol made of the thermochromic
composition would preferably have a thickness of less than
approximately one sixteenth of an inch. In a preferred embodiment,
the composition would be applied directly to the surface by being
sprayed, stenciled, printed, embossed, silkscreened or stamped on
as a liquid that dries. Accordingly, the thermochromic composition
would not have any covering or overcoat in a preferred embodiment.
In a preferred embodiment, the thermochromic composition would be
substantially invisible against a background color of the visible
surface of the grill and would become readily visible against that
background color whenever or would reveal a heat symbol that is
readily visible against that background color and so long as the
specified temperature is reached.
[0144] Typically, the grill has a visible outer perimeter. The
outer perimeter is at or near a conjunction of the hollow container
and the plurality of metal bars. In certain embodiments, this
perimeter has a top surface that is slightly lower than the top
surface of the bars of the grill on which the meat or other food is
placed. However, this is not a critical feature since the food on
the grill is usually not large enough to intrude onto the outer
perimeter and affect the durability of any heat warning device
located thereon. Accordingly, in accordance with this embodiment of
the present invention, a heat warning symbol in accordance with the
present invention would be placed on that outer perimeter. Thus,
the present invention contemplates an improved grill for heating
meat and other food safely.
[0145] The present invention also applies to an indoor grill, one
which can be fitted directly into the recess on top of stove after
the electric coil or other heating element has been removed. In
this case, as best seen from FIGS. 21 and 22, the grill has a drip
pan under it and typically has a metal ring surrounding the drip
pan for holding up the drip pan, as was described in the context of
the electric coil heating element for an electric stove.
Accordingly, the heat warning symbol can appear on the upper lip
220 of drip pan 200, as seen in FIGS. 21-22, or on the metal ring
300 surrounding the drip pan (not shown precisely in the context of
a drip pan around a grill) in accordance with the present
invention.
[0146] In each embodiment of the accessory and improved grill,
improved griddle, improved metal grate, it is contemplated as an
alternative that a thin buffer layer of thermally conductive
adhesive is situated underneath the thermochromic composition and
heat warning layer in order to reduce the temperature of the
thermochromic composition, since grills, griddles and even their
accessories surrounding them (drip pans, metal rings, etc.) can get
extremely hot. Accordingly, although this may seem most useful with
thermochromic composition located on the surface of a griddle or
grill it could also be applied to the composition on a drip pan,
metal ring or other accessory surrounding a heating element.
[0147] Accordingly, although the buffer layer is shown only in
FIGS. 14a and FIG. 22, and not on FIGS. 12, 16, 18, 20 and 24, the
other embodiments also have alternative variations that include the
buffer layer, although the insertion of this layer is not shown on
all of the drawings.
[0148] The thermally conductive adhesive, for example ceramic or
epoxy adhesive made by Cotronics Corp. of Brooklyn, N.Y., would be
placed directly on the outer perimeter surface of the grill and the
thermochromic composition (and in certain embodiments a printed or
inscribed symbol under this composition) would then be applied
directly on top of the buffer layer of thermally conductive
adhesive. The buffer layer is capable of withstanding the very high
temperatures on the outer perimeter of the grill. Depending on the
grill's heating element and diameter, that temperature can be
between approximately 400 degrees Fahrenheit and approximately 900
degrees Fahrenheit.
[0149] Although the thermochromic composition does not require an
overcoat, in certain embodiments where the surface is exposed to
sunlight, since thermochromic compositions deteriorate with
exposure to ultra violet radiation, a UV filter can be applied as a
top clear (see-through) overcoat. In such embodiments, it is also
contemplated to position the heat warning device on a side of the
appliance, such as an outdoor grill, to hide it from exposure to
sunlight.
[0150] Another surface that gets very hot and remains hot even
after the heat source is turned off and which would not accommodate
a very bulky heat warning device is the surface of an indoor or
outdoor griddle. In the case of an indoor griddle, the griddle can
be fitted directly into the recessed burner area of the top surface
of a stove that previously was fitted with an electric heating
element. Such a griddle is depicted in FIGS. 21-24. In FIGS. 21-22,
the heat warning symbol is on the lip of the drip pan. In FIGS.
23-24, the heat warning symbol is on a visible surface of the metal
ring itself. Obviously, combinations of these two versions can be
implemented as well.
[0151] Although FIG. 24 in its entirety represents an indoor
griddle since it includes drip pan 200 and metal ring 300 adjacent
flat metal surface 240, FIG. 24 taken without drip pan 200 and
without ring 300 can also be imagined and in this case these would
represent the essential elements of the outdoor grill of the
present invention together with heat symbol 21 on flat metal
surface 240. Likewise, the same outdoor grill (without drip pan 200
or metal ring 300) that includes buffer layer 260 can also be
appreciated from imagining FIG. 22 without the drip pan 200 and
metal ring 300.
[0152] In the case of an indoor griddle, which may be less
susceptible to the application of accessories such as a drip pan or
a metal ring, an embodiment of the present invention is an improved
griddle itself which comprises a flat metal surface 240 on which
food is exposed to heat, a source of heat 244 connected to the flat
metal surface, the flat metal surface including an outer perimeter,
the outer perimeter having a visible surface, and a heat warning
symbol on the visible surface of the outer perimeter. However, in
this case, since the surface of a griddle gets extremely hot, such
as 900 degrees Fahrenheit in some cases, it is preferred, before
applying the heat warning symbol to the outer perimeter of the
griddle, to first provide for a thin heat conducting layer that
creates a buffer between the thermochromic composition in the heat
warning symbol and the surface of the griddle. The buffer layer
reduces the maximum temperature the thermochromic composition will
be exposed to. For example, a thin layer 260 of certain epoxy can
be both heat conducting but also capable of withstanding
temperatures of over 900 degrees Fahrenheit. Such epoxies are well
known--for example ceramic and epoxy adhesives manufactured by
Cotronics Corp. of Brooklyn, New York under various product names
such as Durabond.RTM. and other product names. In some case such an
epoxy or ceramic adhesive can also be modified to control the exact
degree of its heat conductivity and the temperature up to which it
can withstand by installing metallic fibers into the adhesive. Such
thermally conductive metall-filled adhesives are sold by Cotronics
Corp.
[0153] The buffer layer 260 is merely reducing the heat and not
eliminating it so the epoxy or ceramic adhesive can be thin enough
that the total combined thickness of the heat warning symbol and
the buffer layer of adhesive is still less than one sixteenth of an
inch, and certainly less than one eighth of an inch. The heat
warning symbol 21 would be applied directly to the buffer layer of
adhesive or other material instead of directly to the metallic
surface. Accordingly, the buffer layer of adhesive in accordance
with the present invention would be capable of withstanding the
very high temperature typically reached on the flat metal surface
of the improved griddle. The buffer layer would be tailored to the
particular improved griddle involved. For residential griddles,
that temperature would be lower than for commercial griddles. For
example, for residential griddles, that temperature might be
approximately 700 degrees Fahrenheit. For commercial griddles, that
temperature may be approximately 900 degrees Fahrenheit.
[0154] The heat warning symbol would once again be made of a
thermochromic composition shaped in a predetermined symbol or in
the background of said symbol which communicates that the surface
of the griddle is dangerously hot, the symbol designed to undergo
and maintain a readily perceptible color change whenever and so
long as the temperature of the surface of the griddle exceeds a
predetermined temperature. As noted in the context of the other
embodiments, due to the discrepancy between the temperature of the
griddle and that of the heat warning symbol because of the epoxy
buffer, the triggering temperature at which the symbol will change
color and become visible will be calibrated so as to be
appropriately lower than the actual temperature at which it is
dangerously hot to touch the griddle in order to take this
discrepancy into consideration. The thermochromic composition is
capable of withstanding temperatures in excess of approximately 300
degrees Fahrenheit. It can be effective with target surface
temperatures that greatly exceed that amount, up to approximately
600 degrees to 1200 degrees Fahrenheit The exact target surface
temperature of the griddle would depend upon the size of the
griddle and the distance of the outer perimeter from the heat
source.
[0155] The thermochromic composition is not bulky and in a
preferred embodiment has a thickness of less than approximately one
sixteenth of an inch and in a preferred embodiment lacks any
covering or overcoat. Once again, in a preferred embodiment, the
thermochromic composition would be substantially invisible against
a background color of the visible surface and would become readily
visible against that background color or would reveal a heat symbol
that is readily visible against that background color whenever and
so long as the threshold temperature is reached.
Assembly Embodiment
[0156] The concept of the present invention whereby heat warning
symbols are applied to surfaces of hot appliances can be extended
to an assembly 100 of devices 10 of the present invention. The
combination of the devices 10 forming assembly 100 provides a
system of maximum protection to a whole family so that any and all
surfaces of the appliance or other object can be protected with
warning devices. For example, a toaster's surfaces may cool to
below the specified temperature at different times so the user
needs to place warning device on different surfaces of the
toaster.
[0157] The assembly 100 includes a plurality of heat alert warning
devices that can be placed on more than one surface of an
appliance. The assembly 100 includes one or more devices of a first
type 10A attachable to a first surface 30A of the appliance, the
device of the first type 10A comprising a thermochromic composition
20 shaped in a predetermined symbol or in the background of such
symbol which communicates that the surface is dangerously hot, the
symbol substantially invisible against a background color of the
surface and designed to undergo and maintain a readily perceptible
color change so that the symbol is readily visible against said
background color whenever and so long as the temperature of the
surface exceeds a predetermined temperature, the thermochromic
composition capable of being applied as a liquid directly to the
first surface in the predetermined shape, capable of remaining on
the first surface in its predetermined shape in solid form, and
capable of withstanding temperatures in excess of 300 degrees
Fahrenheit, the thickness in solid form of said thermochromic
composition being such that said thermochromic composition is
either faintly visible or invisible when viewed from a line of
sight tangent to the first surface by someone whose attention is
not specifically directed to said thermochromic composition.
Assembly 100 also includes one or more devices of a second type 10B
attachable to a second surface 30B of the appliance, said device of
the second type comprising a thermochromic composition shaped in a
predetermined symbol or in the background of such symbol which
communicates that the surface is dangerously hot, wherein an
outline of the symbol is visible against a background color of the
surface and a remainder of the symbol is substantially invisible
against a background color of the surface, the remainder of the
symbol designed to undergo and maintain a readily perceptible color
change so that said remainder is readily visible against said
background color whenever and so long as the temperature of the
surface exceeds a predetermined temperature, the thermochromic
composition capable of being applied as a liquid directly to the
surface in the predetermined shape, capable of remaining on said
surface in its predetermined shape in solid form, and capable of
withstanding temperatures in excess of 300 degrees Fahrenheit, the
thickness in solid form of the thermochromic composition being such
that said thermochromic composition is either faintly visible or
invisible when viewed from a line of sight tangent to the second
surface by someone whose attention is not specifically directed to
said thermochromic composition. The assembly 100 could be limited
to the two surfaces or could optionally also include one or more
additional devices that are of the first type or of the second type
attachable to one or more additional surfaces of the appliance.
[0158] The assembly 100 can include as many devices 10 as is
practical and appropriate. Furthermore, the assembly 100
contemplates that there can be more than one device 10 of the first
type 10A on the first surface 30A and more than one device 10 of
the second type 10B on a second surface 30B.
Multiple Segment Embodiment
[0159] The present invention also contemplates that the device 10
can communicate not just that a surface is dangerously hot but also
varying levels of dangerously hot, i.e. varying degrees of heat on
that surface. As seen in FIGS. 9, 10, 11A and 11B, the device 10
can be divided in segments of two, three or any other number.
Typically, there would not be more than three segments because it
is not necessary usually to communicate more than three levels of
heat. In addition, one does not want to clog the visual space of
the surface.
[0160] In accordance with this embodiment, the heat warning safety
device 10 can be described as comprising a thermochromic
composition 20 shaped in a predetermined symbol, the symbol having
multiple segments, or in the background of such symbol, which
symbol communicates that the surface is dangerously hot to a
particular level, each segment 50A, 50B except one communicating a
different level of a degree to which the surface is dangerously hot
and one segment 50C communicating that the surface is not
dangerously hot until the surface temperature exceeds the
predetermined temperature, all segments of the symbol except one
substantially invisible against a background color of the surface
and at least one segment of said symbol designed to undergo and
maintain a readily perceptible color change so that said at least
one segment is readily visible against said background color
whenever and so long as the temperature of the surface exceeds the
predetermined temperature, and a second segment of the symbol
designed to undergo and maintain a readily perceptible color change
so that said second segment is readily visible against the
background color whenever and so long as the temperature of the
surface exceeds a second predetermined temperature, said second
predetermined temperature being higher than said predetermined
temperature, the thermochromic composition capable of being applied
as a liquid directly to the surface in the predetermined shape,
capable of remaining on said surface in its predetermined shape in
solid form, and capable of withstanding temperatures in excess of
300 degrees Fahrenheit, the thickness in solid form of said
thermochromic composition being such that said thermochromic
composition is either faintly visible or invisible when viewed from
a line of light tangent to the surface by someone whose attention
is not specifically directed to said thermochromic composition.
[0161] For example, as seen in FIGS. 11B in general and FIG. 9 as
applied to a cup and a lid, one segment of symbol would for example
communicate the word "OK" to tell the consumer that they can put
the appliance away and it is not hot. Among the remaining two
segments, a first segment would communicate the word "HOT" when the
surface exceeded the predetermined temperature and a second segment
would communicate "VERY HOT" whenever and so long as the surface
temperature exceeded a second (higher) predetermined temperature.
FIG. 11A in general and FIG. 10 applied to a lid of a cup, show the
same idea except there are only two segments of the heat warning
symbol--the "HOT" segment 60A that communicates that the
temperature of the surface exceeded a predetermined temperature and
which is presently invisible and the "OK" segment 60B that
affirmatively communicates that the surface is not dangerously hot
and be touched or moved and which is depicted as visible.
Accordingly, even though only one of the segments is active in the
drawings of these segmented symbols in FIGS. 9-10 and 11A-11B,
there are one or two other segments that although invisible contain
another symbol segment For example, in FIG. 11B, only the "VERY
HOT" segment is active, the "OK" and the "HOT" segments are
invisible since they are not active.
[0162] The above segment 50C which notifies the consumer that the
surface is no dangerously hot can be accomplished by a
thermochromic composition since thermochromic composition are well
known to change color in either direction. In other words, instead
of turning red for example when the predetermined temperature is
exceeded, as is the case with the segments communicating "HOT" and
"VERY HOT", the segment communicating "OK" turns red or another
color different than the background color whenever the temperature
goes below the predetermined temperature.
[0163] It should be noted that although FIGS. 9, 10, 11A and 11B
depict the segments are part of a type one symbol--i.e. it is
invisible when not active and it is visible when active (as opposed
to a type two symbol whose outline is always visible even when not
active)--it is of course contemplated by the present invention that
the same segment embodiment or other alternative embodiment can be
accomplished using the type two symbols or even combinations of the
two types of symbols.
[0164] It should be noted that FIGS. 9, 10, 11A and 11B do not
depict lines dividing the segments within a symbol. The present
invention only contemplates using the thermochromic composition to
do so where doing so does not impair the objective of not clogging
the visual space.
[0165] The present invention also contemplates combining the
segment embodiment with the assembly embodiment. Accordingly,
assembly 100 of devices 10 incorporates the "segment" embodiment
just described. Such an assembly can be described as a heat warning
safety device assembly 100 attachable to multiple surfaces of an
appliance, the assembly 100 for warning individuals that one of
more of the surfaces are hot. The assembly 100 comprises a
plurality of heat alert warning devices including one or more
devices of a first type 10A attachable to a first surface 30A of
the appliance, the device of the first type 10A comprising a
thermochromic composition shaped in a predetermined symbol, the
symbol having multiple segments, or in the background of such
symbol, which symbol communicates that the first surface is
dangerously hot to a particular level, each segment except one
communicating a different level of a degree to which the first
surface is dangerously hot and one segment communicating that the
first surface is not dangerously hot, the symbol substantially
invisible against a background color of the surface and at least
one segment of said symbol designed to undergo and maintain a
readily perceptible color change so that said at least one segment
is readily visible against said background color whenever and so
long as the temperature of the surface exceeds a predetermined
temperature, and a second segment of said symbol designed to
undergo and maintain a readily perceptible color change so that
said second segment is readily visible against said background
color whenever and so long as the temperature of the surface
exceeds a second predetermined temperature, said second
predetermined temperature (i.e. "VERY HOT") being higher than said
predetermined temperature (i.e. "HOT"), the thermochromic
composition capable of being applied as a liquid directly to the
surface in the predetermined shape, capable of remaining on said
surface in its predetermined shape in solid form, and capable of
withstanding temperatures in excess of 300 degrees Fahrenheit, the
thickness in solid form of said thermochromic composition being
such that said thermochromic composition is either faintly visible
or invisible when viewed from a line of sight tangent to the first
surface by someone whose attention is not specifically directed to
said thermochromic composition. This assembly 100 also includes one
or more devices of a second type 10B attachable to a second surface
30B of the appliance. The device of the second type 10B comprises a
thermochromic composition shaped in a predetermined symbol or in
the background of such symbol which communicates that the surface
is dangerously hot, wherein an outline of the symbol is visible
against a background color of the surface and a remainder of the
symbol is substantially invisible against a background color of the
surface, and wherein the remainder of the symbol is designed to
undergo and maintain a readily perceptible color change so that
said remainder is readily visible against said background color
whenever and so long as the temperature of the surface exceeds a
predetermined temperature. As before, the thermochromic composition
is capable of being applied as a liquid directly to the surface in
the predetermined shape, capable of remaining on said surface in
its predetermined shape in solid form, and capable of withstanding
temperatures in excess of 300 degrees Fahrenheit. The thickness in
solid form of the thermochromic composition is such that the
thermochromic composition is either faintly visible or invisible
when viewed from a line of sight tangent to the second surface by
someone whose attention is not specifically directed to said
thermochromic composition.
[0166] Optionally, assembly 100 also includes one or more
additional devices that are of the first type or of the second type
and that are attachable to one or more additional surfaces of the
appliance.
[0167] It should be noted that in this description only the first
type 10A of device 10 in assembly 100 is segmented to communicate
varying degrees of heat including "VERY HOT", "HOT" and "OK".
However, the present invention certainly also contemplates
embodiments in which the second type 10B of device 10 in assembly
100 is segmented. The present invention also contemplates an
embodiment in which both the first type 10A and the second type 10B
of device 10 are segmented. Furthermore, there can be additional
devices on additional surfaces that can be segmented. Furthermore,
it is also contemplated by the present invention that the amount of
segmentation (the number of segments in the heat warning symbol)
and the type of segmentation (the subsymbol used in the segment)
can vary from one surface to another within the assembly of devices
and even can vary within the devices that are placed on a single
surface of an appliance.
Additional Embodiments
[0168] As seen in FIGS. 9-10, the present invention also
contemplates an embodiment wherein a heat warning safety device is
attachable to a cup or the lid of a cup or other container that
holds a hot liquid, for advertising the temperature of the liquid.
Such a device 80 comprises a thermochromic composition shaped in a
predetermined symbol or in the background of such symbol which
communicates that a top surface of the lid is dangerously hot, the
symbol substantially invisible against a background color of the
surface and designed to undergo and maintain a readily perceptible
color change so that the symbol is readily visible against said
background color whenever and so long as the temperature of the top
surface of the lid exceeds a predetermined temperature, said
predetermined temperature of the top surface of the lid calibrated
to reflect a higher temperature of the liquid in the cup by taking
into consideration an expected specified amount of heat dissipation
between the liquid and the lid, the thermochromic composition
capable of being applied as a liquid directly to the surface in the
predetermined shape, capable of remaining on said surface in its
predetermined shape in solid form, and capable of withstanding
temperatures in excess of 300 degrees Fahrenheit, the thickness in
solid form of said thermochromic composition being such that said
thermochromic composition is either faintly visible or invisible
when viewed from a line of light tangent to the surface by someone
whose attention is not specifically directed to said thermochromic
composition.
[0169] In general, it is to be understood that while the apparatus
of this invention have been described and illustrated in detail,
the above-described embodiments are simply illustrative of the
principles of the invention. It is to be understood also that
various other modifications and changes may be devised by those
skilled in the art which will embody the principles of the
invention and fall within the spirit and scope thereof. It is not
desired to limit the invention to the exact construction and
operation shown and described. The spirit and scope of this
invention are limited only by the spirit and scope of the following
claims.
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