US3846608A — High temperature resistant door seal for a microw…

Claim 1

Independent Claim 456 words

In a microwave oven having a heating chamber within which foodstuffs to be heated by exposure to microwave energy radiation are received, an entry opening at an end of said chamber to provide access to said chamber, an annular border region surrounding said entry opening, and a movable door operable between an open and closed position to prevent exit of microwave energy radiation, said door including a middle door portion to cover said entry opening to said chamber and an annular border region about said middle door portion which covers, at least in part, said annular border region surrounding said heating chamber entry opening to form opposed annular regions, and microwave energy seal means to prevent radiation leakage from physical gaps between said annular door portion and annular border region; the improvement in said combination wherein said microwave energy seal means comprises: a choke type seal which includes a first elongated continuous electrically conductive walled cavity of predetermined depth located behind one of said annular border regions and extending about said entry opening; and a narrow opening in said first cavity located in said one of said annular border regions and extending entirely about said entry opening and spaced a predetermined distance from said entry opening for providing microwave energy pervious path between said cavity and from about said opposed annular regions; a dissipative seal which includes a second elongated cavity underlying one of said annular regions and extending about said entry opening, a narrow opening in said second cavity located in said one of said annular regions and extending about said entry opening and spaced a predetermined distance therefrom for providing a passage between said annular region and said second cavity, microwave energy dissipating means located partially within, extending about, and protruding from said narrow opening in said second cavity, spring means located within and extending about said second cavity for providing a force on said dissipative means in a direction outwardly of said second cavity to force said dissipative means outwardly from said opening in said second cavity and apply a pressure to the opposed one of said annular regions; a third seal which includes a compressible strip of electrically lossy material located on one of said annular regions and extending about said entry opening for compressive engagement between said annular door region and said annular border region surrounding said chamber; and wherein said opening in said first cavity is spaced from said opening in said second cavity by a predetermined distance within the range of 0.02 and 0.24 inch and is located more proximate said entry opening than said opening in said second cavity and wherein said opening in said second cavity is located more proximate said entry opening than said third seal.

Claim 2

Dependent Claim 456 words

In a microwave oven having a heating chamber within which foodstuffs to be heated by exposure to microwave energy radiation are received, an entry opening at an end of said chamber to provide access to said chamber, an annular border region surrounding said entry opening, and a movable door operable between an open and closed position to prevent exit of microwave energy radiation, said door including a middle door portion to cover said entry opening to said chamber and an annular border region about said middle door portion which covers, at least in part, said annular border region surrounding said heating chamber entry opening to form opposed annular regions, and microwave energy seal means to prevent radiation leakage from physical gaps between said annular door portion and annular border region; the improvement in said combination wherein said microwave energy seal means comprises: a choke type seal which includes a first elongated continuous electrically conductive walled cavity of predetermined depth located behind one of said annular border regions and extending about said entry opening; and a narrow opening in said first cavity located in said one of said annular border regions and extending entirely about said entry opening and spaced a predetermined distance from said entry opening for providing microwave energy pervious path between said cavity and from about said opposed annular regions; a dissipative seal which includes a second elongated cavity underlying one of said annular regions and extending about said entry opening, a narrow opening in said second cavity located in said one of said annular regions and extending about said entry opening and spaced a predetermined distance therefrom for providing a passage between said annular region and said second cavity, microwave energy dissipating means located partially within, extending about, and protruding from said narrow opening in said second cavity, spring means located within and extending about said second cavity for providing a force on said dissipative means in a direction outwardly of said second cavity to force said dissipative means outwardly from said opening in said second cavity and apply a pressure to the opposed one of said annular regions; a third seal which includes a compressible strip of electrically lossy material located on one of said annular regions and extending about said entry opening for compressive engagement between said annular door region and said annular border region surrounding said chamber; and wherein said opening in said first cavity is spaced from said opening in said second cavity by a predetermined distance within the range of 0.02 and 0.24 inch and is located more proximate said entry opening than said opening in said second cavity and wherein said opening in said second cavity is located more proximate said entry opening than said third seal.

Claim 3

Dependent Claim 51 words

The invention as defined in claim 1 wherein said dissipative seal further comprises an elongated sleeve of high temperature resistant pliant microwave energy pervious material, said sleeve being divided into two elongated compartments and wherein each of said microwave energy dissipating means and said spring means are located within said sleeve.

Claim 4

Dependent Claim 15 words

The invention as defined in claim 2 wherein said microwave dissipative material comprises a ferrite.

Claim 5

Dependent Claim 16 words

The invention as defined in claim 3 wherein said spring comprises a wire mesh tubular spring.

Claim 6

Dependent Claim 16 words

The invention as defined in claim 2 wherein said sleeve material comprises braided glass fiber fibers.

Claim 7

Dependent Claim 36 words

The invention as defined in claim 4 wherein said wire mesh tubular spring has a predetermined cross-sectional diameter and wherein said predetermined diameter is greater than the width of said narrow opening in said second cavity.

Claim 8

Dependent Claim 29 words

The invention as defined in claim 1 wherein said predetermined distance between said opening in said first cavity and said opening in said second cavity comprises approximately 0.03 inch.

Claim 9

Dependent Claim 33 words

The invention as defined in claim 6 wherein said predetermined distance between said opening in said first cavity and said opening in said second cavity comprises between 0.025 inch and approximately 0.050 inch.

Claim 10

Dependent Claim 28 words

The invention as defined in claim 1 wherein said one of said annular regions, which said second elongated cavity underlies, comprises said annular border region on said door.

Claim 11

Dependent Claim 31 words

The invention as defined in claim 9 wherein said one of said annular border regions in which said first cavity is located behind, comprises said annular border region of said door.

Claim 12

Dependent Claim 29 words

The invention as defined in claim 10 wherein said one of said annular region on which said third seal is located, comprises said annular border region of said door.

Claim 13

Dependent Claim 28 words

The invention as defined in claim 6 wherein said one of said annular regions, which said second elongated cavity underlies, comprises said annular border region on said door.

Claim 14

Dependent Claim 31 words

The invention as defined in claim 12 wherein said one of said annular border regions in which said first cavity is located behind, comprises said annular border region of said door.

Claim 15

Dependent Claim 29 words

The invention as defined in claim 13 wherein said one of said annular region on which said third seal is located, comprises said annular border region of said door.

Claim 16

Dependent Claim 43 words

The invention as defined in claim 6 further comprising a dirt seal, said dirt seal comprising a high temperature resistant material pervious to microwave frequency energy and relatively impervious to dirt particles, said dirt seal located in said opening in said first cavity.

Claim 17

Dependent Claim 30 words

The invention as defined in claim 15 wherein said compressible strip of electrically lossy material comprises a rubber having a substantially lower temperature resistance than said sleeve and said ferrite.

Claim 18

Dependent Claim 127 words

The invention in a dissipative seal which comprises: a door for a microwave oven; a cavity in said door extending thereabout in a continuous loop; a narrow opening in the surface of said door, said opening extending about said door in said same continuous loop; an elongated sleeve of braided glass fiber material, said sleeve being divided into two elongated compartments and extending about said cavity; an elongated tubular mesh spring installed in one of said compartments and ferrite material installed in the other of said compartments, and wherein the diameter of said tubular mesh spring is greater than the width of said opening, said tubular mesh spring being located within said cavity and said ferrite material and a portion of said sleeve protruding from said opening.

Claim 19

Dependent Claim 127 words

The invention in a dissipative seal which comprises: a door for a microwave oven; a cavity in said door extending thereabout in a continuous loop; a narrow opening in the surface of said door, said opening extending about said door in said same continuous loop; an elongated sleeve of braided glass fiber material, said sleeve being divided into two elongated compartments and extending about said cavity; an elongated tubular mesh spring installed in one of said compartments and ferrite material installed in the other of said compartments, and wherein the diameter of said tubular mesh spring is greater than the width of said opening, said tubular mesh spring being located within said cavity and said ferrite material and a portion of said sleeve protruding from said opening.

Claim 20

Dependent Claim 234 words

In a microwave oven having a cooking chamber for receiving foodstuffs to be heated, outer walls forming a container within which said oven chamber is located and a front wall portion between said outer walls and said cooking chamber to form an annular region about said cooking chamber, and a movable door for closing the front end of said chamber, said door having an annular region which overlaps said annular region of said container when said door is in the closed position, the improvement therein comprising: a first conductively walled chamber located within said door, said chamber having a passage opening in said annular region and spaced a predetermined distance from said cooking chamber for providing a microwave energy leakage-inhibiting effect; a second chamber, said second chamber having a restricted portion and an opening therein in said annular portion of said door, said second chamber having a metal wall in common with said first chamber, said wall having an edge exposed in said annular portion, said wall having a thickness in the range of 0.02 to 0.20 inch; microwave energy absorbing material located in said second chamber and protruding therefrom for abutment with said annular container portion and spring means located in said chamber for biasing said microwave energy absorbing material against movement into said chamber; and a loss-loaded rubber strip forming a gasket between said annular portions of said door and said container.

Claim 21

Dependent Claim 234 words

In a microwave oven having a cooking chamber for receiving foodstuffs to be heated, outer walls forming a container within which said oven chamber is located and a front wall portion between said outer walls and said cooking chamber to form an annular region about said cooking chamber, and a movable door for closing the front end of said chamber, said door having an annular region which overlaps said annular region of said container when said door is in the closed position, the improvement therein comprising: a first conductively walled chamber located within said door, said chamber having a passage opening in said annular region and spaced a predetermined distance from said cooking chamber for providing a microwave energy leakage-inhibiting effect; a second chamber, said second chamber having a restricted portion and an opening therein in said annular portion of said door, said second chamber having a metal wall in common with said first chamber, said wall having an edge exposed in said annular portion, said wall having a thickness in the range of 0.02 to 0.20 inch; microwave energy absorbing material located in said second chamber and protruding therefrom for abutment with said annular container portion and spring means located in said chamber for biasing said microwave energy absorbing material against movement into said chamber; and a loss-loaded rubber strip forming a gasket between said annular portions of said door and said container.

Claim 22

Dependent Claim 27 words

The invention as defined in claim 18 wherein each of said annular portions of said door and said oven container include a coating of vitreous enamel material.

Claim 23

Dependent Claim 35 words

The invention as defined in claim 19 further comprising a sleeve of high temperature resistant pliant material and wherein each of said spring means and said microwave energy absorbing means are positioned within said sleeve.

Claim 24

Dependent Claim 40 words

The invention as defined in claim 20 further comprising seam means for dividing said sleeve into two compartments and wherein said microwave energy-absorbing material is located in a first compartment and said spring means is located in a second compartment.

Claim 25

Dependent Claim 15 words

The invention as defined in claim 21 wherein said sleeve material comprises braided glass fiber.

Claim 26

Dependent Claim 37 words

The invention as defined in claim 22 further comprising a strip of glass fiber material positioned within said entrance of said first cavity for providing a barrier to dirt particles while permitting passage of microwave energy therebetween.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-11-04	1978-05-06	1978-11-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-11-04	1982-05-06	1982-11-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-11-04	1986-05-06	1986-11-05	$7700.00	Window Closed / Lapsed

High temperature resistant door seal for a microwave oven

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