Note: Descriptions are shown in the official language in which they were submitted.
CA 02566819 2006-11-22
HEATING DEVICE COMPRISING A TRAY WITH A COVER
FIELD OF THE INVENTION
This invention relates to a heating device for maintaining foods at
temperatures suitable for
serving or for even cooking foods.
BACKGROUND OF THE INVENTION
to Most restaurants which specialize in serving cooked food rapidly--indeed,
essentially with
the placement of an order--do not have the capacity to prepare large
quantities of food on
demand. Thus, traditional meal times, particularly the noon hour, place severe
demands on
these restaurants. Typically, the so-called "fast food" restaurant will
prepare some cooked
food in advance of a meal time and keep that food warm in a holding oven.
Then, during a
meal time when the demand is greatest, it will use the food previously cooked.
Some cooked foods, such as hamburger patties, should be held at elevated
temperatures only
in a moist environment, since these foods, when depleted of their moisture
content have poor
taste and texture. Other cooked foods, such as breaded chicken or fish
fillets, should be
2o stored such that moisture may escape, so that they remain crisp. While it
is convenient to
store different foods at the same location, the flavor of one food should not
transfer to
another food. Moreover, irrespective of the food, the temperature at which it
is stored must
remain high enough to prevent bacterial contamination, and this generally
requires holding
the food at temperatures in excess of about 150° F. Holding ovens that
are currently in
use in fast food restaurants do not fully satisfy these requirements.
The holding ovens of current manufacture accept trays containing the cooked
foods. The
typical oven has a cabinet containing storage spaces which are accessible from
both the front
and rear of the cabinet, so that a tray containing cooked food may be placed
into a storage
3o space at one face of the cabinet and withdrawn at the other face. Each
storage space has a
heated platen along its top and also preferably at its bottom, and these
platens transfer heat to
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the trays. The cabinet also contains a mechanism for closing the upper ends of
the trays to
prevent moisture from escaping. In one type of holding oven this mechanism
resides in
making the spacing between a heated platen on which the tray rests and the
heated platen
which overlies the tray about equal to the height of the tray, so that the
upper margin of the
tray lies along and essentially against the overlying platen, thus in effect
closing the tray. See
U.S. Pat. No. 5,724,886. Another type of holding oven supports the tray on a
resilient grate
which urges a tray upwardly against an overlying heated platen, thereby
effecting a seal with
the overlying platen. See U.S. Pat. No. 5,783,803. These ovens are difficult
to clean and do
not efficiently concentrate the heat at the trays where it is needed. As a
consequence, the food
1o is often held at a temperature less than optimum. Sometimes, the spaces in
these ovens hold
trays with their tops open and this leads to a transfer of flavors between
multiple trays in any
one space. In any event, ovens of current manufacture have the capacity to
store foods for
only very limited periods of time.
BRIEF SUMMARY OF THE INVENTION
The present invention resides in an oven having a channel-shaped heat sink
which is heated
by a heater. The heat sink has a storage cavity which generally conforms to
the shape of a
tray or other food container received in the cavity. As such, the heat sink
concentrates the
2o heat generated by the heater at the tray so as to efficiently maintain the
food in the tray at a
temperature suitable for serving. The heat sink may have a cover for closing
the top of the
tray within it. Where the oven contains multiple heat sinks, these heat sinks
are isolated from
each other to prevent the flavor of the food in one from transferring to food
in another.
The invention therefore provides, in combination with a heating device and
with a tray
located within the heating device and having a rim that is presented upwardly
around the
interior of the tray, a self supporting cover for establishing at least a
partial closure over the
rim of the tray, said cover comprising: first and second legs in an upright
orientation and
having lower margins for supporting the cover, the legs being spaced far
enough apart to
receive the rim of the tray between them; and a cross wall attached to the
legs above their
lower margins and extending between the legs, the space between the legs and
below the
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cross wall being open at least one end of the cover, so that the rim of the
tray may be inserted
between the legs and below the cross wall at that end of the cover.
The invention also provides, in combination with a heat sink having shoulders
and a tray
s located within the heat sink, a cover for at least partially closing the
tray while the tray is in
the heat sink, said cover comprising: upright legs which are located over the
shoulders of the
heat sink and project upwardly away from the shoulders; and a cross wall
extending between
the legs and the tray.
1o The invention further relates to an oven comprising: a cabinet; a plurality
of trays adapted to
be inserted in the cabinet and withdrawn from the cabinet, each tray having a
bottom wall,
side walls extending upwardly from the bottom wall, and an open top; self
supporting covers
in the cabinet for respective trays, each cover having a generally horizontal
cross wall and a
pair of side walls extending downwardly from the cross wall at opposite sides
of the cross
1s wall, said cross wall having a width which exceeds the width of a
respective tray to allow the
tray to be positioned in the cabinet between the side walls of the cover with
the cross wall
extending over the open top of the tray; each cover being releasably retained
in the cabinet
against withdrawal from the cabinet when a respective tray is removed from
between the side
walls of the cover and withdrawn from the cabinet, the side walls of the cover
supporting the
2o cover in the cabinet after the tray has been withdrawn from the cabinet;
and a heating
element positioned in the cabinet to direct heat into trays in the cabinet.
The invention also relates to an oven comprising: a cabinet; horizontal
shoulders in the
cabinet; a plurality of trays adapted to be inserted in the cabinet and
withdrawn from the
2s cabinet, each tray having a bottom wall, side walls extending upwardly from
the bottom wall,
and an open top; covers in the cabinet for respective trays, each cover having
a generally
horizontal cross wall and a pair of side walls extending downwardly from the
cross wall at
opposite sides of the cross wall over respective horizontal shoulders in the
cabinet, said cross
wall having a width which exceeds the width of a respective tray to allow the
tray to be
3o positioned in the cabinet between the side walls of the cover with the
cross wall extending
over the open top of the tray; each cover being releasably retained in the
cabinet against
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withdrawal from the cabinet when a respective tray is removed from between the
side walls
of the cover and withdrawn from the cabinet, the side walls of the cover
resting on said
respective shoulders after the tray has been withdrawn from the cabinet; and
at least one
opening in the cross wall of at least one of said covers for venting the
cover.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which form part of the specification and wherein
like
numerals and letters refer to like parts wherever they occur:
l0
FIG. 1 is a front and top perspective view of a holding oven constructed in
accordance with
and embodying the present invention, with one of the covers and one of its
trays shown
removed;
FIG. 2 is a top and rear perspective view of the oven;
FIG. 3 is a transverse sectional view of two heat sinks, one having its cover
in its sealing
position and the other having its cover in the venting position;
FIG. 4 is a fragmentary sectional view taken along line 4--4 of FIG. 3;
FIG. 5 is an exploded perspective view of a heat sink, the cover for the heat
sink, and a tray;
FIG. 6 is a perspective view of a modified cover.
FIG. 7 is an exploded perspective view of the heat sink, a modified cover for
the heat sink,
and a modified tray; and
FIG. 8 is a fragmentary longitudinal sectional view of the modified tray of
FIG. 7 fitted
beneath the modified cover of FIG. 7.
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Corresponding reference numerals will be used throughout the several figures
of the
drawings.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring now to the drawings, an oven A (FIGS. 1 &2) holds multiple trays B
in which
precooked food is placed and held for limited times, indeed, several hours in
the case of some
foods. The oven A and the trays B, which are used with it, will accommodate a
variety of
foods typical of those served in fast food restaurants. Among those foods are
cooked
to hamburger patties, ham, bacon, sausage, onion rings, French toast, fish
fillets, chicken fillets
and biscuits. Thus, the trays B constitute food containers. The oven A heats
the trays B from
their bottoms as well as their sides. Moreover, one who places a tray B in the
oven A has the
option of closing the top of the tray B so as to retain moisture in the tray B
or leaving the top
open so that moisture may escape from the tray B.
Considering the trays B first, they are preferably molded from a polymer that
is capable of
withstanding the temperatures maintained in the oven A, although trays B of
stamped metal
will suffice as well. In any event, such a tray B has (FIGS. 3-5) a flat
bottom wall 2 and also
side walls 4 and end walls 6 that merge with the bottom wall 2 at corners 8 of
generous
2o radius. The side walls 4 and end walls 6 flare outwardly slightly and each
has an offset
portion 10 near its upper end. The offset portions 10 of the walls 4 and 6,
along their upper
margins, merge into a rim in the form of a peripheral lip 14 which projects
laterally
outwardly and, beyond the side walls 4, turns slightly downwardly at a
depressed edge 16
(FIG. 3). The lip 14 has a flat upper surface 18 that lies in a common plane
along the entirety
of the lip 14. At the end walls 6 the lip 14 merges into handles 20 which lie
below the plane
of the upper surface 18. Similar trays see widespread use in fast food
restaurants.
The oven A includes (FIGS. 1 &2) a cabinet 26 having a front panel 28, a rear
panel 30, end
panels 32, and a top panel 34. The front panel 28 and rear panel 30 contain
openings 36
3o which conform generally to the cross-sectional configuration of the trays
B, but are slightly
wider and somewhat taller. The openings 36 are arranged in several tiers, and
for every
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opening 36 in the front panel 28 an opening 36 in the rear panel 30 aligns
with it. The cabinet
26 at each tier of openings 36 also has (FIGS. 3 and 4), an upper pan 38 that
extends through
it above the openings 36 and a lower pan 40 that extends through it below the
openings 36.
The upper pan 38 has a peripheral lip 41 which projects upwardly and imparts
rigidity to the
pan 38. The pan 38 carries channels 42 which extend between the front and rear
panels 28
and 30 in the regions between the openings 36. More channels 42 lie beyond the
two
endmost openings 36 as well. The channels 42 are attached firmly to the pan 38
and open
downwardly. The lower pan 40 for each tier has lips 43 that project upwardly
and turn
inwardly and, beneath the inwardly turned portions, has rigidifying members
44. The space
to between the upper and lower pans 38 and 40 for each tier of openings 36 is
occupied by
several heat sinks 46--one for each pair of aligned openings 36 in the tier.
Each heat sink 46 is formed from a substance that conducts heat well, aluminum
being
preferred. When formed from aluminum, the heat sinks 46 may be produced as
extrusions or
castings or they may even be produced by machining. Irrespective of how it is
produced,
each heat sink 46 possesses (FIG. 5) a channel-like configuration in that it
is open at both
ends and at its top and closed along its two sides and bottom. This leaves the
heat sink 46
with a cavity 48 that extends the full length of the heat sink 46. The open
ends of the cavity
48 align with openings 36 in the front and rear panels 28 and 30 of the
cabinet 26, so that the
cavity 48 of the heat sink 46 is easily accessible from the exterior of the
oven A. The cavity
48 generally conforms to the exterior cross-sectional configuration of any
tray B.
More specifically, each heat sink 46 includes (FIGS. 3&5) a bottom wall 50 and
side walls
52 which are formed integral with the bottom wall 50 and project upwardly from
it. The
bottom wall 50 is of uniform thickness, it being about 3/16 in. thick, and has
a flat bottom
surface 54 and a flat top surface 56. In contrast, the two side walls 52,
while being mirror
images of each other, have somewhat varied thickness. Each side wall 52 has a
lower region
58 that generally corresponds in height to the height of a tray B. The lower
region 58 has a
flat outside surface 60 and a contoured inside surface 62 that merges with the
flat top surface
56 of the bottom wall 50 at a curved comer 64. Immediately above the comer 64,
the inside
surface 62 flares outwardly slightly, then after undergoing a more abrupt
change in direction,
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extends vertically for a lesser distance. The spacing between the inside
surfaces 62 for the
side walls 52 of the heat sink 46 is slightly greater than the width of the
tray B measured
across of the outside surfaces of its side walls 4. Moreover, the inside
surfaces 62 of the side
walls 52 on the heat sink 46 generally conform in configuration to the outside
surfaces for the
side walls 4 of the tray B. When the tray B is inserted into the heat sink 46
with the bottom
wall 2 of the tray B resting in the flat top surface 56 of the bottom wall 50
for the heat sink
46, the side walls 4 of the tray B, despite their contoured configuration, are
close to the inside
surfaces 62 on the side walls 52 of the heat sink 46. Generally, the spacing
at any elevation
between the inside surfaces 56 on side walls 52 of the heat sink 46 should be
no more than
to about 1.0 in. larger than the spacing between the side walls 4 of the tray
B at the outside
surfaces of those side walls 4. Thus, when the tray B is centered in the
cavity 48 of the heat
sink 46, a clearance of no more than about 0.5 in. exists between the inside
surfaces 62 of the
side walls 52 for the heat sink 46 and the outside surfaces in the side walls
4 of the tray B.
Preferably, when the tray B is centered, the clearance is about 0.015 in. The
curved comers
64, where the flat bottom surface 54 and contoured inside surfaces 62 of the
heat sink 46
merge, lie opposite, yet close to, the corners 8 of the tray B.
The lower region 58 of each side wall 52 for the heat sink 46 merges into an
upper region 66
at an offset 68. The upper regions 66 extend vertically and by reason of the
offsets 68, the
2o spacing between the upper regions 66 exceeds the spacing between the lower
regions 58.
Indeed, that spacing exceeds the width of the tray B at its peripheral lip 14.
The contoured
inside surfaces 62 on the lower regions 58 of the side walls 52 rise to flat
horizontal
shoulders 70 which extend over the offsets 68 and out to the upper regions 66.
The shoulders
70 lie in a plane that is parallel to the top surface 56 of the bottom wall
52, and the distance
between the shoulders 70 and the top surface 56 is slightly less than the
distance between the
lower surface of the bottom wall 2 for the tray B and the undersurface of the
lip 14 at the side
walls 4 which undersurface is at the depressed edge 16. Thus, when the tray B
rests on the
bottom wall 2 of the heat sink 44, the depressed edge 16 of the lip 14 beyond
each side wall 4
lies slightly above the shoulders 70. The lip 14 remains well below the upper
edges of side
3o walls 52 for the heat sink 46.
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Those upper edges lie along the upper regions 66 of the side walls 52 for the
heat sink 46,
and here the upper regions 66 are enlarged slightly and received in the
channels 42 that are
attached to the upper pan 38 for the tier in which the heat sink 46 lies (FIG.
3). The bottom
wall 50 of the heat sink 46 at its ends rests on the inwardly turned portions
of the lips 43 for
the lower pan 40. (FIG. 4) to which it is fastened. Thus, the heat sinks 46
for any tier are
captured between the upper and lower pans 38 and 40 for the tier. The channels
42 confine
the heat sinks 46 of the tier laterally, whereas the front and rear panels 28
and 30 confine
them longitudinally. In short, the heat sinks 46 are fixed in position in the
cabinet 26.
1o Each heat sink 46 is fitted with a heater which may take the form of a
flexible heating
element 76 of the electrical resistance type. It extends almost the full
length of the heat sink
44, covering the flat bottom surface 54 of the bottom wall 50, the corners
between the bottom
wall 50 and side walls 52, and the flat outside surfaces 60 on the lower
regions 58 of the side
walls 52. It even curves outwardly along the bottom surfaces of the offsets 68
in the side
walls 52. To these surfaces the heating element 76, which is preferably film-
etched, is
bonded, preferably with a silicone adhesive capable of withstanding the
elevated
temperatures produced by the heating element 76. In this regard, the heating
element 76
should produce enough heat and reach a temperature high enough to elevate the
temperature
of the heat sink 46 along the top surface 56 of its bottom wall 50 and along
the contoured
2o inside surfaces 62 of its side walls 52 to a temperature suitable for
maintaining food within
the tray B that occupies that heat sink 46 at any desired temperature. Where
the oven A
serves as a holding oven, that temperature keeps the food warm enough for
serving and warm
enough to prevent bacterial contamination. Where the oven A functions as a
cooking oven,
that temperature is hot enough to actually cook the food.
Other types of heaters may be used as well. For example, the heater may take
the form of
resistance type heating rods embedded in the bottom wall 50 and in the lower
regions 58 of
the side walls 52. Steam or hot water may be circulated through channels in
the bottom wall
50 and lower regions 58 of the side walls 52 to maintain the heat sink 46 at
an elevated
3o temperature, in which case the channels and the fluid that flows within
them become the
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heater. On the other hand, if the heat sink 46 is formed from a ferrous
material, an induction
heating device may be used to elevate the temperature.
Behind the side walls 52 of each heat sink 46 and beneath its bottom wall 50,
as well, the
cabinet 26 is packed thermal insulation 78. The lower pans 40 in the cabinet
26 support the
insulation 78 and prevent the insulation 78 for any one tier of heat sinks 46
from dropping
into the heat sinks 46 of the tier below.
In addition to its heating element 78, each heat sink 46 is equipped with a
cover 80 that rests
on the shoulders 70 of its offsets 68 and generally occupies the space between
the upper
regions 66 of its side walls 52. The cover 80 includes a pair of vertical legs
82 and a cross
wall 84 that extends between and is attached to the vertical legs 82. Indeed,
the cross wall 84
is joined to the vertical legs 82 between the longitudinal edges of the legs
82, it being offset
closer to one longitudinal edge of each leg 82 than the other. However, near
its ends the cross
wall 84 flares away from the edges to which it is closest. The width of the
cross wall 84
slightly exceeds the width of the tray B at its lip 14. The height of the
vertical legs 82 is
slightly less that the height of the upper regions 66 of the two side walls 52
for the heat sink
44. These dimensions enable one to easily slide the cover 80 into and out of
the upper region
of its heat sink 44.
The configuration of the cover 80 is such that it may assume two positions
within the space
between the upper regions 66 of the side walls 52 for the heat sink 44--a
closing position
(FIG. 3-left) and a venting position (FIG. 3-right). In the closing position
the cross wall 84 of
the cover 80 rests on the upper surface 18 of the lip I4 of the tray B, or
else lies slightly
above the upper surface 18 of the lip 14. In either arrangement the cross wall
84 serves as a
closure for the tray B. Where the cross wall 84 actually rests on the lip 14
the legs 82 project
downwardly almost to the flat horizontal shoulders 70 of the heat sink 46, but
do not contact
the shoulders 70. The lower margins of the legs 82 lie between the lips 14 on
the tray B and
the upper regions 66 of the side walls 52 for the heat sink 46. When the tray
B is removed
3o from the heat sink 46, the legs 82 of the cover 80 drop downwardly and rest
on the shoulders
70 of the heat sink 46. But the ends of the cross wall 84 flare upwardly,
leaving enough space
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between the shoulders 70 and those flared ends to accommodate the handles 20
of a tray B.
On the other hand, where the cross wall 84 lies slightly above the upper
surface 18 on the lip
14, the legs 82 project downwardly to and actually rest on the flat horizontal
shoulders 70 of
the heat sink 46 with the lip 14 on the tray B being between the regions of
contact. A
clearance ranging up to 0.375 in. exists between the bottom of the cross wall
84 and the
upper surface 18 on the lip 14. The legs 82 extend up to and nearly contact
the overlying
upper pan 38 of the cabinet 26. In the venting position the cover 80 is
reversed. Its legs 82
rest on the shoulder 70 of the heat sink 46 outwardly from the peripheral lip
14 of the tray B,
but the cross wall 84 lies well above the peripheral lip 14 and the handles
20. This leaves an
to open space of at least 0.375 in. between the cross wall 84 of the cover 80
and upper surface
18 on the lip 14 of the tray B at each end wall 6 of the tray B, and moisture
from the tray B
may escape through these spaces.
At the sides of the openings 36 in the front panel 28 and rear panel 30, the
cabinet 26 is fitted
with pivotal stops 88 of the triangular configuration. Each triangular stop 88
serves two
openings 36. It pivots at one of its apices, with the pivot axis being
slightly above, but
otherwise between, the two openings 36 that the stop 88 serves. The other two
apices project
beyond the upper regions 66 of the nearby side walls 52 for the heat sinks 46
at those
openings 36. As such, those other apices project past the ends of the openings
36, but not
2o across, the openings 36.
The free apices of the stops 88 lie beyond the ends of the vertical legs 82
for the covers 80
and retain the covers 80 in the upper regions of the heat sinks 46. However,
to reverse a
cover 80 and thereby change its position, the stop 88 at the heat sink 46 in
which the cover 80
fits, is pivoted away from the opening 36 at that heat sink 46 so as to no
longer block the
opening 36. While the stop 88 is held away from the opening 36, the cover 80
is removed and
reversed. Then the cover 80 is inserted back through the opening 36 in the
reversed position.
Once the cover 80 is fully within the heat sink 44, the stop 88 is released,
and it assumes its
normal position, blocking the end of the opening 36 and thereby retaining the
cover 80 in the
3o heat sink 46.
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Finally, the cabinet 26 contains electrical controls 92 which control the
temperature at which
the heating element 76 of the sinks 46 operate. A separate control 92 exists
for each tier of
heat sinks 46. However, the controls 92 may be such that each heat sink 46 is
controlled
individually.
The oven A normally awaits use in a restaurant with some of its covers 80 in
the sealing
position and the remainder of its covers 80 in the venting position. As a meal
time
approaches, the employees of the restaurant cook various foods for which the
restaurant
expects to receive orders during the meal time. Immediately after these foods
are prepared,
1o they are placed in the trays B, each food being assigned to a different
tray B. Some of these
foods, such as hamburger patties, loose their taste and texture with loss of
moisture. Others,
such as fried chicken fillets, biscuits, and eggs become soggy if stored in an
abundance of
moisture. The trays B which contain foods that must remain moist are placed in
heat sinks 46
having their covers 80 in the closing position (FIG. 3-left). The trays B
containing foods
which must remain crisp are placed in heat sinks 46 in which the covers 80 are
in the venting
position (FIG. 3-right). Each heat sink 44 directs heat through the bottom
wall 2 and side
walls 4 of the tray B that is within it, and the heat keeps the food in the
tray B warm--indeed,
warm enough to prevent bacterial contamination and warm enough to serve to
patrons of the
restaurant when the demand arises, all with the flavor and texture preserved.
To insert a tray B into a heat sink 44 having its cover 80 in the closing
position, the restaurant
employee brings the tray B to the rear panel 30 of the cabinet 26 and aligns
it with one of the
openings 36 at a heat sink 46, the cover 80 for which is in its closing
position. The employee
inserts the handle 20 of the tray B beneath the upwardly flared end on the
cross wall 84 for
the cover 80 in that heat sink 46. Thereupon, the employee advances the tray B
into the heat
sink 46, with the lip 14 of the tray B passing beneath the cross wall 84 of
the cover 80. When
the tray B is fully within the heat sink 46, the cross wall 84 of the cover 80
establishes a
closure over the open top of the tray B and that wall 84 lies over the entire
lip 14 along the
periphery of the tray B. Moisture remains trapped within the tray B, even
though the heat
3o which is supplied by the heat sink 46 has the capacity to drive moisture
from the food. As a
consequence, the food in the tray B retains its taste and texture.
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On the other hand, if the tray B contains a food which must remain crisp, the
employee
selects a heat sink 46 which has its cover 80 in the venting position. The
tray B when aligned
with the opening 36 for this heat sink 46 passes easily into the cavity 48 of
the heat sink 46
with little manipulation, its lip 14 passing over the shoulders 70 of the heat
sink 46 and its
bottom wall 2 over the top surface 56 for the bottom wall 50 of the heat sink
46. The cross
wall 84 for the cover 80 remains well above the lip 14 on the tray B, so that
moisture from
the food within the tray B may escape at the open ends of the cover 80, that
is to say over the
end walls 6 of the tray B and beneath the cross wall 84 of the cover 80.
When the demand for a particular food arises within the restaurant, other
employees remove
the tray B containing that food from the oven A. This simply involves grasping
the tray B by
one of its handles 20 and withdrawing it from its heat sink 46. In this
regard, the handles 20
project beyond the front and rear panels 28 and 30 of the cabinet 26 and are
easily accessible.
Any cover 80 is easily withdrawn from its heat sink 46 by pivoting the stop 88
at the one end
of the heat sink 46 away from the opening 36 at the end of that heat sink 46.
This leaves the
cavity 48 of the heat sink 46 unobstructed, and it is easily cleaned, owing to
its continuous
and smooth surfaces. It also enables an employee to easily clean the cover 80.
And, of
course, it permits the employee to reverse the position of the cover 80.
The heat sink 46 efficiently transfers heat from its heating element 76 to the
tray B, thereby
keeping the contents of the tray B at a desired temperature with minimum
expenditure of
electrical energy. The foods in the tray B that are withdrawn, even as long as
several hours
after being inserted into the oven A, have essentially the taste and texture
that they possessed
immediately after being cooked. Since the trays B are totally isolated from
each other in
separate compartments in the cabinet 26, even when the covers 80 over those
trays are in
their venting positions, flavors are not transferred between the foods in
different trays B. In
one embodiment, each compartment is defined by bottom wall 50, side walls 52,
and top wall
38, but other embodiments are possible for preventing transfer of flavors
between
compartments.
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A modified cover 100 (FIG. 6) has side legs 82 and a cross wall 84 of
essentially the same
configuration as their counterparts in the cover 80. However, the cross wall
84 contains
openings 102 arranged in a row between the legs 82. It also carries a slide
104 which
likewise contains openings 106. The slide 104 is captured on the cross wall 84
such that it
cannot be lifted from the cross wall 84, yet it can slide longitudinally over
the wall 84.
Indeed, the slide 104 projects beyond the ends of the cross wall 84, so that
it can be
manipulated from the exterior of the oven A to assume various positions on the
cross wall 84.
In one position, the slide completely covers the openings 102 in the wall 84,
and in this
position the tray B is sealed. In other positions the slide 104 exposes the
openings located
l0 within and being joined to the elevated region 116. The depressed region
118 has a peripheral
wall 120 that is generally vertical and a bottom wall 122 which lies below,
yet parallel to, the
surrounding elevated region 116.
When the tray C is in the cavity 48 of the heat sink 46 (FIG. 8), the bottom
surface of the
elevated region 116 in the cross wall 114 lies directly above the upper
surface 18 on the tray
B, there being a gap of about 0.375 in. between the two surfaces. The
peripheral wall 120, on
the other hand, is set inwardly from the upper surface 18 of the tray C and
inwardly from the
upper ends of the side walls 4 and end walls 6 as well, with the gap being
about 0.375 in. The
lower surface of the bottom wall 122 lies in a horizontal plane that is
slightly above the plane
defined by the upper surface 18 on the tray C, with the spacing between the
two planes being
about 0.01 in. This spacing allows the tray C to be inserted into and removed
from the cavity
48 of the heat sink 46 without interference from the cover 110.
At the ends of the cover 110 the elevated region 116 of the cross wall 114
turns downwardly
in the form of a vertical lip 124, the lower edge of which lies in the plane
of the lower surface
on the bottom wall 122. When the tray C is in the heat sink 46, the lips 124
lie slightly
beyond the upper surfaces 18 at the ends of the tray C, yet over or slightly
beyond the
depressed edges 16 at those ends. The lips 124 and the nearby segments of the
peripheral
wall 120 for the depressed region 118 create labyrinths which retard moisture
from escaping
from the tray C.
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CA 02566819 2006-11-22
To enhance the seal established by the lips 124 and the depressed region 118
of the cover
110, the lips 124 may be fitted with elastomeric seal elements which bear
against the end
edges of the laterally directed lip 14 of the tray C beyond the two end walls
6 of the tray C.
Likewise, elastomeric lip seals may also be fitted to the ends of the cross
wall for the cover
80 to contact the lip 14 at the ends of the tray C and thereby enhance the
sealing capabilities
of the cover 80.
The rear panel 30 of the cabinet 26, in lieu of having openings 36, may be
solid. In such an
arrangement the rear panel 30 would block one end of the cavity 48 for each
heat sink 46,
to and the heat sink 46 itself could wrap around the end of the cavity to
close it and thus,
transfer heat to that end wall 6 of the tray B which is presented toward the
closed end. The
other end of the heat sink 46 would remain open and indeed would open out of
the cabinet 36
through the aligned opening 36 in the front panel 28. Of course, the handle 20
on that end of
the tray B which faces the closed end of the heat sink 46 would have to be
removed or
reconfigured, so that it will not interfere with the solid rear panel 30.
Also, any tray B or C which must retain moisture may be fitted with a separate
cover, and
that would eliminate the need for the covers 80 or 110. In this regard, covers
are available on
the market for the traditional trays that resemble the trays B and C.
This invention is intended to cover all changes and modifications of the
example of the
invention herein chosen for purposes of the disclosure which do not constitute
departures
from the spirit and scope of the invention.
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