Patent US4230968A successfully refreshed from Google Patents.
US4230968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cathode structure for magnetrons
Assignee: Hitachi Ltd
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Filing: 1979-02-07
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Granted: 1980-10-28
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Expires: 1999-02-07
Abstract
Abstract The cathode filament of a magnetron is constituted by a metallic cylindrical body provided with a plurality of perforations. The cylindrical body may be made of a cylinder or formed by helically winding a web of a metal strip.
Inventors
- 👤 Tomokatsu Oguro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:33
CPC Classifications
H; H01; H01J; H01J23/00; H01J23/02; H01J23/04; H01J23/05
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
127 words
In a magnetron of the type including a cathode structure and an anode structure surrounding the cathode structure, wherein said cathode structure includes a filament, upper and lower end shields secured to the opposite ends of the filament for supporting the same, and a center support and a side support respectively supporting said upper and lower end shields and also acting as electric leads, the improvement comprising: a filament in the form of a metallic cylindrical body provided with a plurality of openings therethrough; said upper and lower end shields further including upper and lower cylindrical cups having the openings thereof facing each other for receiving the cylindrical filament and wherein the opposite ends of the cylindrical filament are contained within and supported by the cylindrical cups.
Claim 2
Dependent Claim
127 words
In a magnetron of the type including a cathode structure and an anode structure surrounding the cathode structure, wherein said cathode structure includes a filament, upper and lower end shields secured to the opposite ends of the filament for supporting the same, and a center support and a side support respectively supporting said upper and lower end shields and also acting as electric leads, the improvement comprising: a filament in the form of a metallic cylindrical body provided with a plurality of openings therethrough; said upper and lower end shields further including upper and lower cylindrical cups having the openings thereof facing each other for receiving the cylindrical filament and wherein the opposite ends of the cylindrical filament are contained within and supported by the cylindrical cups.
Claim 3
Dependent Claim
15 words
The magnetron according to claim 1 wherein said cylindrical body comprises a single metal cylinder.
Claim 4
Dependent Claim
30 words
The magnetron according to claim 1 wherein said cylindrical body is formed by first bending a metal sheet into a cylindrical shape and then etching said plurality of openings therethrough.
Claim 5
Dependent Claim
47 words
The magnetron according to claim 1 wherein said cylindrical body comprises a knitting of metal wires and wherein opposite ends of said knitting of metal wires are respectively contained within said upper and lower cylindrical cups so as to maintain the dimensional stability of said cylindrical body.
Claim 6
Dependent Claim
27 words
The magnetron according to claim 1 wherein said cylindrical body comprises a metal web provided with a plurality of perforations and helically wound into the cylindrical body.
Claim 7
Dependent Claim
29 words
The magnetron according to claim 5 wherein said perforations are arranged in such a pattern to control the direction of flow of the current flowing through said cylindrical body.
Claim 8
Dependent Claim
26 words
The magnetron according to claim 5 wherein said perforations are arranged in parallel with the axis of said cylindrical body within the width of said web.
Claim 9
Dependent Claim
31 words
The magnetron according to claim 4 wherein the opposite ends of said knitting of metal wires are respectively welded to the inside cylindrical walls of said upper and lower cylindrical cups.
Claim 10
Dependent Claim
37 words
The magnetron according to claim 8 wherein said knitting of metal wires includes a plurality of individual metal wires which are interwoven but not otherwise attached to one another outside of said upper and lower cylindrical cups.
Claim 11
Dependent Claim
33 words
The magnetron of claim 5 wherein the metal web is formed of perforated metal strip having a width substantially greater than the thickness thereof and having a length greater than the width thereof.
Claim 12
Dependent Claim
26 words
The magnetron of claim 10 wherein the dimensions of the perforations exceed the thickness of the strip and are less than the width of the strip.
Claim 13
Dependent Claim
131 words
In a magnetron of the type including a cathode structure and an anode structure surrounding the cathode structure, wherein said cathode structure includes a filament, upper and lower end shields secured to the opposite ends of the filament for supporting the same, and a center support and a side support respectively supporting said upper and lower end shields and also acting as electric leads, the improvement comprising: a filament in the form of a metallic ribbon helically wound to form a cylindrical body with the ends of said ribbon connected to said end shields to define a helical current path therebetween, said web being perforated with a pattern of openings to reduce the cross-section of the ribbon as a current conductor while maintaining its overall area outline as an electron emitter.
Claim 14
Dependent Claim
131 words
In a magnetron of the type including a cathode structure and an anode structure surrounding the cathode structure, wherein said cathode structure includes a filament, upper and lower end shields secured to the opposite ends of the filament for supporting the same, and a center support and a side support respectively supporting said upper and lower end shields and also acting as electric leads, the improvement comprising: a filament in the form of a metallic ribbon helically wound to form a cylindrical body with the ends of said ribbon connected to said end shields to define a helical current path therebetween, said web being perforated with a pattern of openings to reduce the cross-section of the ribbon as a current conductor while maintaining its overall area outline as an electron emitter.
Claim 15
Dependent Claim
33 words
The magnetron of claim 12 wherein the metal web is formed of perforated metal strip having a width substantially greater than the thickness thereof and having a length greater than the width thereof.
Claim 16
Dependent Claim
31 words
The magnetron according to claim 13 or 14 wherein said perforations are arranged in such a pattern to control the direction of flow of the current flowing through said cylindrical body.
Claim 17
Dependent Claim
26 words
The magnetron according to claim 14 wherein said perforations are arranged in parallel with the axis of said cylindrical body within the width of said web.
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) | 1983-10-28 | 1984-04-28 | 1984-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-28 | 1988-04-28 | 1988-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-28 | 1992-04-28 | 1992-10-28 | $7700.00 | Window Closed / Lapsed |