US3854021A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnetic heating system which includes an automatic shielding mechanism and method for its operation
Assignee: SPX Technologies Inc
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Filing: 1973-07-18
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Granted: 1974-12-10
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Expires: 1993-07-18
Abstract
Abstract A tray inserted into an electromagnetic oven positions an energy shield to interfit with elements on the tray to isolate selected items upon the tray from the electromagnetic energy and operates interlock devices to activate the microwave energy source.
Inventors
- 👤 D Moore
- 👤 W Leyers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:49
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/76; H05B6/766; H05B6/6447
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
115 words
An electromagnetic oven system for heating materials carried on a tray comprising an oven cavity having electrically conductive walls and an open end for receiving trays inserted therein, a door to open and close said open end, means for directing microwave energy into said cavity, an electrically conductive shield mounted for movement in said cavity between an open tray receiving position and a closed position, means including said shield when in said closed position and cooperating with the bottom wall of said cavity to provide substantial shielding of a portion of a tray inserted in said cavity from microwave energy therein, and actuator means for moving said shield from said open to said closed position.
Claim 2
Dependent Claim
115 words
An electromagnetic oven system for heating materials carried on a tray comprising an oven cavity having electrically conductive walls and an open end for receiving trays inserted therein, a door to open and close said open end, means for directing microwave energy into said cavity, an electrically conductive shield mounted for movement in said cavity between an open tray receiving position and a closed position, means including said shield when in said closed position and cooperating with the bottom wall of said cavity to provide substantial shielding of a portion of a tray inserted in said cavity from microwave energy therein, and actuator means for moving said shield from said open to said closed position.
Claim 3
Dependent Claim
43 words
The oven system of claim 1 wherein said actuator means includes linkage means interconnecting said door and said shield and switch means responsive to said linkage whereby said switch assumes a heating enabling position when a tray is properly shielded in said oven.
Claim 4
Dependent Claim
41 words
The oven system of claim 1 including means for detachably and pivotally interconnecting said shield and a rear wall of said cavity, said actuator means including an element detachably engaging said shield for operatively interconnecting the same with said linkage means.
Claim 5
Dependent Claim
40 words
The oven system of claim 1 wherein said actuator means includes a tongue extending into said cavity from said rear wall and having a free outer end, said shield including attachment means for receiving the free end of said tongue.
Claim 6
Dependent Claim
59 words
The combination of claim 1 wherein said shield includes opposed side walls each having a lower edge, a strip in conductive relation with the bottom wall of said cavity and adapted to interfit in side by side shielding relation with a lower edge of at least one of said side walls when said shield is in said closed position.
Claim 7
Dependent Claim
42 words
The combination of claim 5, which includes insulating means positioned between said strip and said lower edge of said shield when said shield is in said closed position, thereby to prevent arcing between said strip and said lower edge of said shield.
Claim 8
Dependent Claim
44 words
The combination of claim 1 including on said tray conductive means defining upstanding flanges adapted to interfit in side by side shielding relation with lower edge portions of the side and front walls of said shield when the latter is in said closed position.
Claim 9
Dependent Claim
26 words
The combination of claim 7, which includes insulating means positioned between said flanges and said lower edge portions when said shield is in said closed position.
Claim 10
Dependent Claim
79 words
The oven system of claim 1 in combination with said tray, said oven cavity having a conductive bottom wall for supporting said tray and a rear wall adjacent one edge thereof, said tray including a conductive strip on the upper surface thereof outlining at least a part of said portion to be shielded, and said shield having at least a front wall with a lower edge positioned adjacent said conductive strip when the shield is in said closed position.
Claim 11
Dependent Claim
46 words
The oven of claim 1 wherein said actuator means includes a depending spring within said shield for engaging the edge of a tray as it is inserted in said oven cavity from said open end for moving said shield from said open toward said closed position.
Claim 12
Dependent Claim
41 words
The oven of claim 10 wherein said spring is positioned to be engaged by said tray before said tray is fully inserted in said cavity whereby continued tray insertion and pivotal movement of said shield toward said closed position proceed simultaneously.
Claim 13
Dependent Claim
35 words
The oven of claim 10 wherein said actuator means includes second linkage means interconnecting said door and said shield for biasing said shield forcefully against an inserted tray in response to closing of said door.
Claim 14
Independent Claim
51 words
The method of heating objects in a cavity adapted to receive microwave energy comprising the steps of locating the objects in a predetermined array on a tray, lowering a shield over the objects in response to insertion of the tray in the cavity, and heating those objects not within the shield.
Claim 15
Independent Claim
51 words
The method of heating objects in a cavity adapted to receive microwave energy comprising the steps of locating the objects in a predetermined array on a tray, lowering a shield over the objects in response to insertion of the tray in the cavity, and heating those objects not within the shield.
Claim 16
Dependent Claim
34 words
The method of claim 13 including the step of securing said shield in position over a tray in said cavity, and activating a heating circuit in response to closing a door to the cavity.
Claim 17
Dependent Claim
115 words
An electromagnetic oven system for heating selected materials on a tray comprising an oven cavity having an opening for receiving trays, a door to open and close said opening, means defining a horizontal conductive tray support in said cavity, means for supplying microwave energy to said cavity, an electrically conductive shield mounted for movement in said cavity between an open tray receiving position and a closed position, means including said shield when in said closed position and cooperating with said tray support to provide substantial total shielding of a portion of a tray inserted in said cavity from microwave energy therein, and actuator means for moving said shield from said open to said closed position.
Claim 18
Dependent Claim
115 words
An electromagnetic oven system for heating selected materials on a tray comprising an oven cavity having an opening for receiving trays, a door to open and close said opening, means defining a horizontal conductive tray support in said cavity, means for supplying microwave energy to said cavity, an electrically conductive shield mounted for movement in said cavity between an open tray receiving position and a closed position, means including said shield when in said closed position and cooperating with said tray support to provide substantial total shielding of a portion of a tray inserted in said cavity from microwave energy therein, and actuator means for moving said shield from said open to said closed position.
Claim 19
Dependent Claim
13 words
The combination of claim 15, wherein said tray is made of insulating material.
Claim 20
Dependent Claim
43 words
The combination of claim 16, wherein there is provided means for preventing the bottom edge of said shield from producing dielectric breakdown of the material of said tray in the vicinity of said bottom edge when said shield is in said closed position.
Claim 21
Dependent Claim
53 words
The combination of claim 15, wherein said tray is made of plastic material, and conductive means on said tray and adapted to cooperate with the bottom edge of said shield when in said closed position to distribute the microwave field within the material of said tray in the vicinity of said bottom edge.
Claim 22
Dependent Claim
40 words
The combination of claim 18, wherein said conductive means includes a thin conductive strip secured to said tray and positioned to be in the vicinity of the bottom edge of said shield when said shield is in said closed position.
Claim 23
Dependent Claim
32 words
The combination of claim 19, wherein said conductive strip is relatively wide as compared to said bottom edge of said shield, thereby to reduce field concentration within the material of said tray.
Claim 24
Dependent Claim
61 words
The combination of claim 15, wherein said tray is made of insulating material and is provided with a relatively wide conductive strip on the upper surface thereof in the vicinity of the bottom edge of said shield when said shield is in said closed position, thereby to prevent microwave energy from entering the area of said tray covered by said shield.
Claim 25
Dependent Claim
51 words
The combination of claim 15, which includes means for moving said shield from said open position to said closed position as said tray is inserted into said cavity and in such manner that the forward edge of said shield moves substantially vertically in relation to said tray as it is inserted.
Claim 26
Dependent Claim
66 words
The combination of claim 15, which includes a member mounted on said tray in a position somewhat ahead of the forward edge of said shield when said shield is in said closed position, whereby said member acts as a barrier to prevent food items from being positioned in an area where they will be struck by said shield as it is moved to said closed position.
Claim 27
Dependent Claim
33 words
The oven system of claim 15, wherein said actuator means is responsive to insertion of a tray into said cavity for moving said movable shield portion from said open to said closed position.
Claim 28
Dependent Claim
39 words
The combination of claim 15, which includes means for preventing the application of microwave energy to said cavity in the event said shield is not properly positioned relative to a tray on said conductive tray support in said cavity.
Claim 29
Dependent Claim
50 words
The combination of claim 15, wherein said shield is detachably mounted in said cavity, and means for preventing the application of microwave energy to said cavity in the event a tray has been inserted in said cavity and said door closed without said shield also being mounted in said cavity.
Claim 30
Dependent Claim
63 words
An electromagnetic oven system for heating selected mAterials on a tray comprising, an oven cavity having an opening for receiving trays, means for supplying microwave energy to said cavity, and shielding means at least a portion of which is attached to and positioned within said cavity for substantially totally shielding a portion of a tray positioned in said cavity from microwave energy therein.
Claim 31
Dependent Claim
63 words
An electromagnetic oven system for heating selected mAterials on a tray comprising, an oven cavity having an opening for receiving trays, means for supplying microwave energy to said cavity, and shielding means at least a portion of which is attached to and positioned within said cavity for substantially totally shielding a portion of a tray positioned in said cavity from microwave energy therein.
Claim 32
Dependent Claim
27 words
The combination of claim 27, which includes actuator means for moving a portion of said shielding means from an open tray-receiving position to a closed shielding position.
Claim 33
Dependent Claim
45 words
The combination of claim 28, wherein said movable shield portion includes conductive side and front walls, the bottom edges of which are positioned over said tray when said shield portion is in said closed position, thereby to define said totally shielded portion of said tray.
Claim 34
Dependent Claim
32 words
The combination of claim 28, wherein said shielding means includes a rear wall of said cavity which cooperates with said movable shield portion to define said totally shielded portion of said tray.
Claim 35
Dependent Claim
33 words
The combination of claim 28, wherein said shielding means includes a conductive tray support within said cavity which cooperates with said movable shield portion to define said totally shielded portion of said tray.
Claim 36
Dependent Claim
18 words
The combination of claim 28, wherein said movable shield portion is pivotally mounted for movement within said cavity.
Claim 37
Dependent Claim
50 words
The combination of claim 32, wherein the tray is provided with a rim portion, and means on said movable shield portion and adapted to be engaged by said rim portion as the tray is removed from the oven to facilitate pivotal movement of said shield portion to said open position.
Claim 38
Dependent Claim
31 words
The combination of claim 28, which includes alarm means for indicating when said movable shield portion is not properly positioned relative to a tray which has been positioned in said cavity.
Claim 39
Dependent Claim
39 words
The combination of claim 27, wherein said shield portion is detachably mounted in said cavity, and alarm means for indicating when a tray has been inserted into said cavity without said shield portion being also positioned within said cavity.
Claim 40
Dependent Claim
86 words
An electromagnetic oven system for heating selected materials on a tray comprising, an oven cavity having an opening for receiving trays, means for supplying microwave energy to said cavity, means for positioning a tray at a predetermined location within said cavity, and shielding means at least a portion of which remains in said cavity while a plurality of trays are successively positioned within said cavity for substantially completely shielding a portion of a tray positioned at said predetermined location in said cavity from microwave energy therein.
Claim 41
Dependent Claim
86 words
An electromagnetic oven system for heating selected materials on a tray comprising, an oven cavity having an opening for receiving trays, means for supplying microwave energy to said cavity, means for positioning a tray at a predetermined location within said cavity, and shielding means at least a portion of which remains in said cavity while a plurality of trays are successively positioned within said cavity for substantially completely shielding a portion of a tray positioned at said predetermined location in said cavity from microwave energy therein.
Claim 42
Independent Claim
103 words
The method of selectively heating objects in a cavity adapted to receive microwave energy comprising the steps of, locating the objects in a predetermined array on a tray with at least one of said objects in a predetermined area of said tray which is unshielded when outside said cavity, inserting said tray with said objects located thereon into a predetermined area of said cavity, substantially completely shielding said area of a tray when located in said predetermined area of said cavity against microwave energy therein, and supplying microwave energy to said cavity to heat those objects outside said shielded portion of said tray.
Claim 43
Independent Claim
103 words
The method of selectively heating objects in a cavity adapted to receive microwave energy comprising the steps of, locating the objects in a predetermined array on a tray with at least one of said objects in a predetermined area of said tray which is unshielded when outside said cavity, inserting said tray with said objects located thereon into a predetermined area of said cavity, substantially completely shielding said area of a tray when located in said predetermined area of said cavity against microwave energy therein, and supplying microwave energy to said cavity to heat those objects outside said shielded portion of said tray.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |