Pneumatic oven door gasket

A pneumatic gasket adapted to be used in an oven door construction in which the door is adapted to be sealed to an oven surface when the door is closed. The gasket is an elongate extensile elastomeric member with first and second sections. The second section is a hollow member which is sealed at its ends or at other desired locations, the space between each of these sealed points forming a hollow air chamber of substantial volume which will expand when exposed to the temperatures produced by an operating oven. The second section may be sealed to produce the air chambers by adhesives such as a room temperature vulcanizing adhesive or by mechanical means. The second section may be a coextensive flap hingedly secured along one edge of the first section. The gaskets have means connected to the first sections removably to secure them to the oven surface to hold them in place between the oven and the door, while allowing them easily to be removed to replace them or to clean the oven.

BACKGROUND OF THE INVENTION 
The invention relates to a gasket primarily adapted for sealing the doors 
of cooking ovens and more specifically to a novel gasket having one or 
more air chambers for effecting such sealing. 
A removable gasket with a flap hingedly connected along one edge has been 
previously proposed to provide a seal for oven doors. One such gasket 
which is adapted removably to be secured to an oven door is disclosed in 
U.S. Pat. No. 3,765,400. The flat flap of this gasket extends outwardly 
from the oven face when the gasket is installed so that it will be engaged 
by the door surface and compressed to form a seal therebetween; however, 
this flap may not engage fully or tightly along its length to give a 
complete seal. 
The invention provides a gasket with a second section or flap which 
includes an air chamber. When the oven door is closed and the oven is 
operating, the oven operating heat expands the air and improves the seal 
by expanding the gasket thickness between the surface of the door and the 
oven face. 
SUMMARY OF THE INVENTION 
The above and other disadvantages of prior art oven gaskets and oven 
sealing techniques are overcome in accordance with the present invention 
by providing a gasket having an air chamber or chambers which will expand 
when exposed to oven operating temperatures. The gasket comprises an 
elongate gasket member with a first section incuding means for securing 
the gasket to an oven door. A second section includes the air chambers and 
may be a hinged flap integral with the first section. The second section 
includes one or more hollow air chambers which are sealed at their ends by 
a room temperature vulcanizing adhesive, or other sealing means such as a 
mechanical closure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
According to the invention, a sealing structure is achieved by means of a 
plurality of gaskets which are emovably secured to the face of an oven 
around the opening of the cooking chamber which is to be closed by an oven 
door. The door is swung into position over the opening, engaging the 
gaskets around the opening, which gaskets have one or more air chambers 
which contain a substantial amount of air which expands when exposed to 
heat. The air chambers thereby seal the opening to reduce the loss of heat 
from the oven during operation. The ends of the air chambers are 
preferably sealed by means of room temperature vulcanizable (RTV) 
adhesive. 
In FIG. 1 there is partially illustrated an oven 10, having a front framing 
wall 12 and provided with a cooking chamber 14 which has an opening 
defined by sides 16 and a top edge 18. There is a conventional oven door 
20 hingedly connected (not shown) to the oven 10 and suitably sprung (not 
shown) to enable its being swung over the cooking chamber 14 to confront 
the face or surface of the wall 12 or swung away from the opening of the 
chamber 14 to give access to the cooking chamber. The exact construction 
of the door and its mechanism is of no consequence to the invention, 
except for the fact that the interior surface 21 (FIG. 6) of the door 20 
is intended to engage upon the gaskets 22 placed around the opening of the 
cooking chamber 14. 
The gaskets 22 are shown engaged adjacent the sides 16 and adjacent the top 
edge 18 of the opening of the oven cooking chamber 14. These three sides 
of the cooking chamber opening are the ones usually sealed. Each of the 
gaskets 22 is constructed in the same manner; however, the upper gasket 
may be somewhat longer than the other two. Each of the gaskets 22 is 
easily installed and readily removable, for cleaning the wall 12 of the 
oven or for replacing the gaskets. The gaskets 22 will preferably be made 
of an extruded heat-resisting elastomer, such as silicone rubber. 
The construction of the gaskets 22 and the preferable securing means are 
best seen in FIGS. 2-4. The gasket 22 is comprised of a first section, an 
elongate rectangular cross section tubular member 24 of elastomeric 
material, such as for example silicone rubber or the like having a central 
bore 26 (FIG. 4). The gasket 22 has a second section integral with the 
first section. The second section preferably is an exterior protruding 
flap 28 hingedly connected along one edge of the first section. In U.S. 
Pat. No. 3,765,400 a hinged flap is provided; however it is a thin, flat 
member intended to extend outwardly when the gasket is installed so that 
it can be engaged by the surface of the door 20 and compressed to form the 
seal. 
The invention contemplates the provision of a hollow bore 30 in the second 
section or flap 28 which is sealed by the described sealing method to 
provide a hollow air chamber or chambers 32 which entrap a substantial 
volume of air or other expandable fluid. A preferable method of sealing 
the air chambers 32 is to insert globules of RTV cement in the bore 30 and 
permit them to vulcanize to form a plug 34 of solidified but elastomeric 
material in the bore 30 at the desired locations. The air chambers 32 
between the plugs 34, or other type of closures, will expand when exposed 
to heat to enhance the sealing of the cooking chamber 14. 
There are known securing means to secure the gaskets 22 to the wall 12 of 
the oven. The securing means illustrated in FIGS. 2-4 are described in 
U.S. Pat. No. 3,765,400. Each end of each gasket 22 has a metal insert 36 
engaged in the hollow bore 26. Each of the inserts is an elongate strip of 
metal having an integral hook 37 formed on one end. Securement of the 
metal insert 36 within the hollow bore 26 is achieved by means of RTV 
adhesive bonding the insert 36 in place. The portion of the bore 26 not 
filled by the RTV or the insert 36 may leave a small amount of trapped 
air, but it does not enhance the sealing of the cooking chamber 14 as do 
the air chambers 32 of the invention. 
"Substantial" as used herein to define the size of the air chamber 32 and 
the quantity of entrapped air is intended to mean, that the quantity of 
air will be such that on expansion by oven heat, the width of the gasket 
will expand measurably or the gasket will acquire a pressure internally 
capable of resisting compression. The gaskets 22 are extensile or 
stretchable material formed of a uniform cross section by extrusion. This 
enables the two sections of the gaskets 22 to be formed integrally and 
cheaply. 
In use, the gaskets 22 may be secured to the wall 12 by any known mounting 
technique; however, as shown in FIGS. 1 and 2, the wall 12 may be provided 
with perforations 38. There would be a pair of perforations for each side 
of the opening of the oven chamber 14 which is to have a gasket connected 
thereto. Utilizing as a securing means, the previously mentioned inserts 
36, the distance between the pair of perforations 38 is made slightly 
greater than the length of the gasket 22. To install the gasket, the 
assembler stretches the gasket endwise and hooks the hooked formations 37 
into the respective perforations 38. This applies tension to the gasket 
and keeps it engaged against the wall 12. 
Each gasket 22 may be easily stretched and removed to clean the oven or to 
replace the gasket. In place of the securing means or inserts 36 there has 
also been provided, in the prior art, a metal piece (not shown) which is 
extended through the entire length of the central bore 26. The ends of the 
metal piece or strip were flexed or bent to insert them in the suitably 
placed perforations 38. 
FIGS. 5 and 6 illustrate the operation of the air chamber 32 of the gasket 
22. The gasket 22 is mounted to the surface of the wall 12 of the oven 10 
by any suitable method. Only one of the gaskets 22 is illustrated; 
however, there would typically be three mounted around the cooking chamber 
14 as shown in FIG. 1. In FIG. 5 the air chamber 32 is illustrated at room 
temperature with the oven door swung away from the surface. In FIG. 6 the 
air chamber is illustrated in its operative form providing a seal between 
the oven face and the interior surface 21 of the closed oven door 20. The 
seal is formed by the expansion of the fluid contained within the air 
chamber 32 as the oven 10 is heated to its operating temperature. The air 
chamber or chambers 32 expand to form a tight seal between the surface 21 
of the door 20 and surface of the wall 12 of the oven to provide an 
efficient and energy conserving oven operation. 
FIGS. 7 and 8 show two other types of closure for the hollow bore 30. In 
FIG. 7 there is illustrated a mechanical closure 40. In this case the air 
chamber 32 is sealed by the mechanical closure by clamping the mechanical 
closure 40 around the gasket 22. In FIG. 8 there is illustrated a closure 
42 where the end of the bore 30 of the gasket 22 is pinched and sealed in 
this condition, for example, by an adhesive or heat welding. 
FIG. 9 illustrates the bore 30 of the gasket 22 before it is sealed. In 
this embodiment the bore 30 is cylindrical rather than rectangular as 
previously illustrated. The bore 30 could of course have any convenient 
shape and when sealed by an adhesive such as the RTV, the shape of the 
seal may not be perfectly cylindrical or rectangular. 
FIG. 10 shows the gasket 22 with multiple seals or closures 44 in the bore 
30 forming multiple hollow air chambers 32. The multiple seals 44 
preferably may be formed by injecting an adhesive such as RTV into the 
hollow bore 30 to plug the bore where desired. The volume of the air 
chamber or chambers 32 is thus easily controlled and the chambers may be 
located anywhere along the length of the gasket as desired. 
RTV adhesive is well known and there are many formulations available on the 
market. Almost any general adhesive of this type may be used. It is 
typically intended to be vulcanized at room temperature. The invention 
does not exclude adhesives which can be cured by the use of elevated 
temperatures alone or under moist conditions. It should be noted that the 
gasket 22, during its eventual use, is subjected to the heat of the oven 
itself and this serves further to vulcanize the bond of the inserts 36 and 
the plugs 34, where used, of the air chambers 32. 
Modifications and variations of the present invention are possible in light 
of the above teachings. It is, therefore, to be understood that within the 
scope of the appended claims, the invention may be practiced otherwise 
than as specifically described.