U.S. patent number 3,717,138 [Application Number 05/193,097] was granted by the patent office on 1973-02-20 for shielded window arrangement for a heat cleaning oven door.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to Donald L. Upp.
United States Patent |
3,717,138 |
Upp |
February 20, 1973 |
SHIELDED WINDOW ARRANGEMENT FOR A HEAT CLEANING OVEN DOOR
Abstract
A sliding shielded window arrangement for a self-cleaning oven
door having an outer glass panel and a pair of aligned inner glass
panels forming a sealed hot air cavity. The door structure
supporting the glass panels includes an inner panel defining with a
spaced outside panel of the door a vertical air flow channel in the
shield well. A plain or uninsulated flat plate reflective shield is
movable in the channel to a raised blocking position adjacent the
outer glass panel such that when the shield is in its raised
position it defines a relatively large air wash channel for the
exposed inner glass panel and a relatively small cool air channel
communicating respectively with a pair of front and rear laminar
air flow passages to provide an air barrier for the door area above
the outer glass panel to attain allowable outer panel
temperatures.
Inventors: |
Upp; Donald L. (Trotwood,
OH) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
22712279 |
Appl.
No.: |
05/193,097 |
Filed: |
October 27, 1971 |
Current U.S.
Class: |
126/200 |
Current CPC
Class: |
F24C
15/04 (20130101) |
Current International
Class: |
F24C
15/04 (20060101); F24C 15/02 (20060101); F23m
007/00 (); F24c 015/04 () |
Field of
Search: |
;126/200 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myhre; Charles J.
Assistant Examiner: Joyce; Harold
Claims
I claim:
1. In a door for enclosing a heat-cleaning oven, the combination
comprising a front panel, a rear panel and an intermediate panel
each having registering window openings in the upper half thereof,
said front panel and said intermediate panel being spaced apart to
define a lower well below the window level and an upper pocket
above the window level, an outer glass sheet covering the window
opening in said front panel, at least one inner glass sheet
covering the window openings in said intermediate panel and said
rear panel, a movable flat plate shield in said well of a dimension
larger than the window openings having a reflective surface adapted
to face said oven, means for raising and lowering said shield from
said well into an air flow space between said outer glass sheet and
said inner glass sheet, said shield in its raised window blocking
position dividing the air flow space into front and rear vertical
positive convection flow air channels, said raised shield being
spaced closer to said outer glass sheet than to said inner glass
sheet whereby said rear channel depth is comparatively large
relative to said front channel depth, said front panel having
ambient air inlet openings adjacent its lower edge and air outlet
openings adjacent its upper edge providing a continuous air flow
passage communicating between the lower well, the air flow space
and the upper pocket; a laminar air flow panel positioned in the
upper pocket in substantial alignment with said outer glass sheet,
said shield when in its raised window blocking position extending
upwardly with its upper portion in spaced rearward lapping relation
with the lower portion of said laminar panel, said laminar panel
dividing the upper pocket into front and rear laminar flow air
ducts of substantially equal air flow capacity whereby the ambient
air flowing in said front channel after air washing the front side
of said shield and the back side of said outer glass sheet is
distributed between said front and rear ducts while the ambient air
flowing in said rear channel after air washing the back side of
said shield and the front side of said inner glass sheet flows
upwardly through said rear duct such that said front panel and the
front side of said outer glass sheet are maintained at reduced
temperatures during a heat-cleaning operation in said oven.
2. In a door for enclosing a heat-cleaning oven, the combination
comprising a front panel, a rear panel and an intermediate panel
each having registering window openings in the upper half thereof,
said front panel and said intermediate panel being spaced apart to
define a lower well below the window level and an upper pocket
above the window level, an outer tempered glass sheet covering the
window opening in said front panel, a pair of tempered glass sheets
covering the window openings in said intermediate panel and said
rear panel respectively providing a sealed hot air cavity between
said pair of glass sheets, a movable flat plate reflective shield
in said well of a dimension larger than the window openings, means
for raising and lowering said shield from said well into an air
flow space between said outer glass sheet and said pair of glass
sheets, said shield in its raised window blocking position dividing
the air flow space into front and rear vertical positive convection
flow air channels, said raised shield being spaced sufficiently
close to said outer glass sheet to provide an air flow path for
said rear channel approximately three times greater in depth than
said front channel, said front panel having ambient air inlet
openings along its lower edge and outlet openings along its upper
edge providing a continuous air flow path between the lower well,
the air flow space and the upper pocket; a laminar flow panel
positioned in the upper pocket in substantial alignment with said
outer glass sheet, said shield when in its raised window blocking
position extending upwardly with its upper portion in spaced
rearward lapping relation with the lower portion of said laminar
panel, said laminar panel dividing the upper pocket into front and
rear laminar flow air ducts of substantially equal air flow
capacity whereby the ambient air flowing in said front channel
after air washing the front of said shield and the back of said
outer glass sheet is distributed between said front and rear ducts
while the ambient air flowing in said rear channel after air
washing the back of said shield and the front of said intermediate
panel glass sheet flows upwardly through said rear duct such that
said front panel and the front of said outer glass sheet are
maintained at reduced temperatures during a heat-cleaning operation
in said oven.
3. A heat-cleaning oven door of hollow sheet metal construction
having at least a pair of spaced apart first and second panels with
registering rectangular window openings in the upper half of each
said panel, inner and outer glass sheets covering the window
openings in said panels, a rectangular heat reflective shield
carried by the door and adapted to be moved from a lowered hidden
position between said panels to a raised visible position between
said glass sheets, link means pivoted to said shield, an operating
link positioned above said window openings for reciprocal movement
in a horizontal plane between said first and second panels, one end
of said operating link pivotally connected to said link means, the
free opposite end of said operating link providing a strike
portion, a rotatable lock handle operative to rotate a slider plate
on the oven body for locking the door in its closed heat-cleaning
position against the oven body, said slider plate having a latch
hook portion which will pass through a registering slot in the door
in an unlocked angular position, said latch hook adapted to engage
said operating link strike portion such that upon rotating said
handle in a first direction said slider plate is rotated into
position to engage said strike portion causing horizontal movement
of said operating link in said first direction together with
movement of said link means resulting in elevation of said shield
to its raised visible position between said glass sheets, said
latch hook adapted to disengage said operating link strike portion
upon rotating said lock handle in a second direction causing free
horizontal movement of said operating link in said second direction
together with movement of said link means due to gravitational
force on said shield whereby said shield is lowered to its hidden
position between said panels.
4. A heat-cleaning oven door of hollow sheet metal construction
having at least a pair of spaced apart first and second panels with
registering rectangular window openings in the upper half of each
said panel, inner and outer glass sheets covering the window
openings in said panels, a rectangular heat reflective shield
carried by the door and adapted to be moved from a lowered hidden
position between said panels to a raised visible position between
said glass sheets, first and second swinging links pivoted to said
shield at spaced fixed points one above the other, said first
swinging link being an L-shaped lever such that in the shield
lowered position its relative long leg is aligned with and spaced
below the lower edge of said window opening and its relatively
short leg is aligned with and spaced to one side of said window
opening, said L-shaped lever connected to said second panel by
means of a fixed upper pivot located approximately midway between
said L-shaped lever's right-angled corner and the free end of its
relatively short leg, said second swinging link pivotally connected
to said second panel by means of a fixed lower pivot located
vertically below said fixed upper pivot a distance equal to the
vertical spacing of said shield spaced fixed points, pin means
adjacent the upper edge of said door, an inverted double-L shaped
operating link having an elongated slot engaged on said pin means
for reciprocal movement in a horizontal plane, the free lower end
of said inverted double-L link pivoted to the free end of said L
shaped lever relatively short leg, the free opposite end of said
operating link forming a strike portion, a rotatable lock handle
operative to rotate a slider plate on the oven body for locking the
door in its closed heat-cleaning position against the oven body,
said slider plate having a latch hook portion which will pass
through a registering slot in the door in an unlocked angular
position, said latch hook adapted to engage said operating link
strike portion upon rotating said lock handle in a first direction
causing horizontal movement of said operating link in said first
direction together with upward pivoting of said swinging links
resulting in movement of said shield to its raised visible position
between said glass sheets, said latch hook adapted to disengage
said operating link strike portion upon rotating said lock handle
in a second direction causing free horizontal movement of said
operating link in said second direction together with downward
pivoting of said swinging links due to the gravitational force on
said shield whereby said shield is lowered to its hidden position
between said panels.
Description
The present invention relates to windowed oven doors and
particularly to an oven door sliding shield arrangement for use
with household ranges incorporating self-cleaning ovens.
It has been proposed to provide windowed doors for self-cleaning
ovens with an insulated sliding shutter located between a pair of
glass sheets which normally occupies a space below the window level
between adjacent panels of the oven door with linkage for manually
elevating the shutter into radiation obstructing position between
the glass sheets. Such a prior art device is disclosed in U.S. Pat.
No. 3,500,815 issued Mar. 17, 1970 to R. P. DeWese et al. who
further discloses ventilation ports allowing the flow of cooling
air behind the front panel of the door and the outermost glass
sheet. The prior art, however, has failed to achieve a windowed
oven door for a self-cleaning range having an uninsulated flat
plate sliding shield which will maintain outer panel temperatures
at a reduced temperature level with the oven heated to a
self-cleaning temperature while allowing the shield to operate
mechanically with little or no effort on the part of the range
operator.
It is an object of the present invention to provide in an oven door
having spaced inner and outer window panes an uninsulated
reflective sliding flat metal shield between the panes and closer
to said outer pane than to said inner panes to reduce panel
temperatures.
It is another object of the present invention to provide a shielded
windowed oven door having air passages on both the inner and outer
surfaces of the shield in combination with a fixed laminar air flow
panel thereabove to insure cold air wiping of the area above the
window prior to its exit through a suitable vent.
It is still another object of the invention to provide a compact
linkage arrangement for raising and lowering the sliding shield of
an oven window such that a minimum of space is required and which
allows the shield to be raised in unison with the locking of the
oven door.
Further objects and advantages of the present invention will be
apparent from the following description, reference being had to the
accompanying drawings, wherein a preferred embodiment of the
present invention is clearly shown.
In the drawings:
FIG. 1 is a perspective view of a domestic range having an oven
with a window door and latch handle.
FIG. 2 is a front elevational view of the door with a portion of
the front panel and outer window broken away with the shield in the
up position.
FIG. 3 is a vertical sectional view of the door showing the air
flow paths with the shield in the up position.
FIG. 4 is a fragmentary section showing the door interlock in the
shield down position.
FIG. 5 is a fragmentary section view showing the interlock in the
raised shield position.
FIG. 6 is a fragmentary underneath view of the lock partially
closed.
Referring now to the drawings, there is shown in FIG. 1 a free
standing range 10 having a front-opening drop door 12 which
encloses an oven cavity 14, (FIG. 3) surrounded by an oven door
jamb surface 16. The oven has heating means (not shown) which are
employed for baking and broiling and for raising the temperature of
the oven to a self-cleaning level in the general range of
750.degree. F. - 950.degree. F. for removing food soil and grease
splatter that accumulates on the walls of the oven liner during
normal cooking, with the appropriate setting of the controls 18 and
timer 20 on rear control panel 21. The cook top surface 22 having a
front collar 23 has a plurality of surface cooking units therein
such as a pair of front burners 24, 25 and a pair of rear burners
26, 27.
Reference may be had if desired to prior patents and publications
disclosing self-cleaning ovens as for example the U.S. Pat. No.
3,121,158 issued to Hurko. It will suffice to say that indident to
initiating a self-cleaning cycle, the oven door 12 is locked closed
by a hook-type locking slider plate member 158 which engages the
strike portions 168 of an operating link 126 by swinging in a
horizontal plane about a slot 167 and vertical pivot pin 169
arrangement (FIGS. 4 and 5). The slider plate 158 extends through
an access slit 165 and is swung by means of lever handle 162 so as
to be pulled inwardly the distance of slot 167 in a manner to be
explained.
As seen in FIG. 3 the oven door 12 is of generally sheet metal
construction including an outer or front door panel 32, an
intermediate door panel 34 and a rear panel member 36 including a
rear liner panel or shield 38. The outer panel 32 is provided with
a window opening 40 aligned with the window opening 42 in
intermediate panel 34 and window opening 44 in door liner 38. The
opening 40 is covered by a sheet of tempered glass 46, the glass
being held in place by a suitable frame 48 and glass support trim
50. The outer panel 32 is bent rearwardly about its upper and lower
edges to provide a rearwardly extending flange 52 which overlies
rearwardly extending flange 54 of intermediate panel 34 and is
suitably secured as by machine screws 55 while the leg of flange 54
interlocks by means of tabs 53 with the forwardly extending flange
56 of inner door panel 36. The inner door panel 36 has a lower
channel-shaped stiffening rib 58 spot welded or otherwise secured
to inner panel 36 such that intermediate panel spacer screws 60 are
threaded therein. An upper channel shaped rib 62 is suitably
secured as by screws 64 and 66 to inner door panel 36 and liner 38
while speed nut screws 68 secure linear 38 to panel 36. Spacer
screws 61 are provided to support intermediate door panel 34 in
spaced relation from the rib 62.
The window openings 42 and 44 are covered by paired heat resistant
glass sheets 72 and 74 having a peripheral separator 76 and
supported by a U-shaped window holding frame member 78 and trim
members 80 and 82 to provide a sealed hot air cavity 84
therebetween. The upper inturned flange 52 of front panel 32
supports an L-shaped exit vent member 86 whose depending leg 88
supports oven door handle member 90 in spaced relation by means of
through bolts 92 and spacers 94. The horizontal leg 96 of the vent
member 86 has an integrally molded off-set deflector 98 supported
by spaced partitions 100 defining a series of slotted exit air
slots 102 (FIG. 2) for a purpose to be explained.
A laminar air flow plate 104 is vertically supported by means of
spacer bolts 105 so as to be spaced substantially equidistant from
front panel 32 and intermediate panel 34 thereby dividing the upper
casing into front and rear vertical air flow passages 108 and 110
for a purpose to be described. The upper edge of plate 104 is
curved inwardly to upper exit ports 106 for discharging the
combined air from both front and rear air passages.
A vertically sliding flat metal reflective uninsulated shield 116,
shown in FIG. 3 in its upward or raised position completely
shielding the outer window 46, is dimensioned such that it can be
received in the lower pocket or shield well 112. The shield 116 is
formed from heat reflective sheet material which in the preferred
form is unanodized aluminum, and when in its raised position its
upper edge 118 is located above and in rearwardly spaced
overlapping relation to the lower edge portion 120 of the laminar
air flow plate 104 and that the amount of overlap is typically
one-fourth inch.
Referring now to FIG. 2 of the drawings, the mechanism which
controls movement of the shield 116 to its raised and lowered
positions and also coordinates movement of the door locking
apparatus will be described.
Manually operated linkage is provided for transporting the shield
116, of generally rectangular form, upwardly into its blocking
position adjacent the inner face of outermost glass panel 46. The
shield operating means is a linkage mechanism having a combination
of links which are so constructed and proportioned as to length
that a small horizontal motion of the operating lever arm or handle
162 will cause the linkage mechanism attached to the shield to
follow an arcuate path on an enlarged scale. The form of
applicant's linkage includes a pair of shield links 122 and 124 and
an operating link 126. The lower shield link 122 is straight while
the upper shield link 124 is generally L-shaped and has a
stationary pivot 128 approximately intermediate its relatively
short leg 129 attached to the intermediate door panel 34 and a
movable pivot 130 directly connected at the free end of its
relatively long leg 131 attached to the shield 116 adjacent its
upper edge 118. The upper L-shaped link 124 is formed such that
when it is in its shield lowered position, shown in phantom or dash
dot lines in FIG. 2 and indicated in the drawings by the primed
numerals, will have its long leg 131 disposed substantially
parallel to and below the lower horizontal edge 133 of the window
46 and its short leg 129a, 129b disposed substantially parallel and
to the right of the shield right edge 134 so as not to obstruct the
view of the oven cavity through the visible door openings.
The straight link 122 has a stationary pivot 136 attached to the
intermediate door panel 34 and a movable pivot 138 at its free end
attached to the shield 116 adjacent the midpoint of its lower edge
140. It will be noted that when the shield is in its lowered
position the stationary pivots 128 and 136 together with the shield
movable pivots 130 and 138 form a parallelogram with the imaginary
hypotenuse of the right triangle (defined by long leg 131 and short
leg portion 129a) being equal in length to the link 122.
The third operating link 126 is formed in the shape of a double-L
member having its intermediate horizontal leg 142 provided with an
elongated curved slot 144 for the reception of a fixed stud 146
operative to allow for substantially horizontal sliding movement of
the double-L member 126. The member 126 has a vertically depending
leg 148 having a pivot pin 150 linked with the free end of short
leg portion 129b. The upper horizontal leg 154 of the double-L
member 126 is inwardly offset at 155 to provide a stem member 156
(FIGS. 4 and 5) for engagement by the pivotal slider plate member
158 of the oven door latching assembly 160.
The latching assembly 160 includes a locking handle or lever arm
162 shown in its left or door unlocked position in FIG. 4 and its
right or door locked position in FIG. 5. The handle 162 has a
downwardly offset cam plate 163 the bottom surface of which
slidably engages the upper surface of slide plate 158. When the
oven door is closed the latch hook portion 164 of slider plate 158
extends through a horizontal keeper slit 166 in the door. As the
lock handle 162 is swung from left to right the slider plate 158 is
cammed into position to engage the free end or strike 168 of stem
member 156. When the slider plate 158 can swing no further to the
right, because of its engagement with the strike 168, which has
been moved to its full line raised shield position, (FIG. 2), the
camming action pulls a downwardly struck tab 175 of the slider
plate into a notch 176 of underlying latch mounting bracket 177
shown in FIG. 6 as viewed from the underside of the mechanism. The
rearward travel of the slider plate 158 by means of the elongated
slot 167 causes the oven door to be pulled shut and sealed against
a suitable oven seal (not shown) made from woven fiberglass,
asbestos or the like. If the oven door is not closed the slider
plate 158 travels far enough to the left such that the tab 175 will
miss the notch 176 in the lock assembly thereby preventing the
handle 162 from swinging all the way to the right. The lock
assembly is provided with interlock switch means (not shown)
interposed in the power circuit to the oven heating means and which
closes the circuit to the heating means only when the oven door is
closed and locked. When the hook 164 of slider plate 158 engages
the strike 168, it can go no further to the left, thus as the
handle 162 is swung further to the right the slider plate 158
begins to travel toward the rear thereby closing and sealing the
oven door against the jamb 16 and actuates the interlock switch
means.
It will be seen in FIG. 3 that the shield well 112 serves as a
lower room air flow duct in the oven door 12 having an entrance
means in the form of a series of intake ports 170 located in lower
peripheral flange 52.
When the shield 116 is in its raised position during the high
temperature heat cleaning operation ambient temperature room air
enters through the lower intake ports 170, as seen by the arrows,
and flows upwardly through the duct 112 which communicates with a
front air flow channel 172, formed between the front glass pane 46
and the shield 116, and a rear air flow channel 174 formed between
the shield 116 and the glass pane 72.
Attention is directed to front channel 172 which is relatively
small in width in relation to rear channel 174 which is relatively
large in width. In the preferred form front channel 172 is
approximately one-fourth inch in width but in no case is it less
than one-eighth inch in width which has been found to be the
minimum width to provide a heated air flow channel not requiring
forced air means to maintain a positive air flow. The relatively
large rear channel 174 is approximately three-fourths inch in width
or the order of three times the size of front channel 172. Because
the reflective shield 116 is a single metal sheet when it is heated
from the oven by reflection and convection it is heat-conducting so
that air within front channel 172 is heated by the shield during
its passage therethrough to insure a rising convection flow and
thus does not require forced air means to maintain a positive air
flow therein.
The relatively larger air flow in rear channel 174 is heated to a
higher temperature by virtue of contacting glass panel 72 to
provide an air wash coolant for the glass panel 72. It will be
noted that when the relatively cool air of channel 122, in
comparison to the warm air in channel 174, reaches the upper
laminar flow panel 104, the lower edge 120 of which is overlapped
by the upper edge 118 of shield 116, the channel 122 relatively
cool air is divided as indicated by flow arrows 180 and 182 such
that the flow 180 is directed into front laminar air flow passage
or duct 108 and the flow 182 is directed into rear laminar air flow
passage or duct 110. By virtue of this arrangement a portion of the
relatively cool air from channel 172 is diverted or segregated into
front laminar duct 108 to act as an air barrier layer to maintain
the upper area of outer door panel 32 at a relatively cool reduced
temperature while the remaining air from channel 172 is mixed in
rear laminar flow passage 110 with the higher temperature air wash
flowing from rear channel 174 to partially cool the air wash. At
the upper edge of laminar flow panel 104 the relatively cool air
from passage 108 and the relatively warm air from passage 110 are
united and mixed just prior to passing through upper flange ports
106 and exiting into the room through discharge air vents 102.
It will be seen that at the conclusion of the heat-cleaning
operation the lock handle 162 is rotated to the left causing
rotation of the slider plate 158 and disengagement of the latch
lock 164 from the strike 168. Because of the arrangement of the
link means 122 and 124 wherein their movable pivots 130, 138 are
located at spaced fixed points one above the other on the shield
116 which are to the left or the far side of shield center line 117
with respect to the stationary pivots 128, 136. In this way the
leverage of long leg 131 and link 122 is of such a magnitude that
the gravitation effect in the shield 116 will cause the links to
swing in a downward direction to move the shield to its lowered
dash line position.
While the embodiment of the present invention as herein described
constitutes a preferred form, it is to be understood that other
forms may be adopted.
* * * * *