Patent US3846667A successfully refreshed from Google Patents.
US3846667A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetron having external choke structure
Assignee: Hitachi Ltd
•
Filing: 1973-06-25
•
Granted: 1974-11-05
•
Expires: 1993-06-25
Abstract
Abstract A magnetron comprising an air-tight vacuum envelope including a cylindrical anode having a plurality of vanes, a cathode for thermionic emission arranged on the central axis of the anode and magnets for applying magnetic field to the working space between the anode and cathode. The magnetron is further provided with a choke structure having an opening in the vicinity of the input terminal of the air-tight vacuum envelope, the choke structure being arranged outside of the envelope and with its effective length almost one fourth of the wavelength of microwave energy generated by the magnetron.
Inventors
- 👤 H Hisada
- 👤 A Harada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:11
CPC Classifications
H; H01; H01J; H01J23/00; H01J23/14; H01J23/15; H05; H05B; H05B6/00; H05B6/64
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
210 words
A magnetron comprising an air-tight vacuum envelope, a cylindrical anode including a plurality of vanes, a cathode arranged on the central axis of said anode for thermionic emission, an input side insulator, a plurality of magnets for applying a magnetic field to the working space between said anode and cathode, a plurality of supports for supporting said cathode through said input side insulator, means for supplying working current through said supports to said cathode, an input side sealing metal member interposed betweeN said anode and said input side insulator, said input side sealing metal member being hermetically closely attached to said input side insulator, an output side sealing member, an output side insulator, and an output terminal; said air-tight vacuum envelope being defined by said anode, said magnets, said input side insulator, said input side sealing member, said output side sealing member, said output side insulator and said output terminal, wherein said magnetron further comprises a choke structure having an opening in the vicinity of the connection between said input side insulator and said input side sealing metal member, said choke structure having an effective length approximately one fourth of the wavelength of microwave energy oscillated by said magnetron and being arranged on the outside of said air-tight vacuum envelope.
Claim 2
Dependent Claim
210 words
A magnetron comprising an air-tight vacuum envelope, a cylindrical anode including a plurality of vanes, a cathode arranged on the central axis of said anode for thermionic emission, an input side insulator, a plurality of magnets for applying a magnetic field to the working space between said anode and cathode, a plurality of supports for supporting said cathode through said input side insulator, means for supplying working current through said supports to said cathode, an input side sealing metal member interposed betweeN said anode and said input side insulator, said input side sealing metal member being hermetically closely attached to said input side insulator, an output side sealing member, an output side insulator, and an output terminal; said air-tight vacuum envelope being defined by said anode, said magnets, said input side insulator, said input side sealing member, said output side sealing member, said output side insulator and said output terminal, wherein said magnetron further comprises a choke structure having an opening in the vicinity of the connection between said input side insulator and said input side sealing metal member, said choke structure having an effective length approximately one fourth of the wavelength of microwave energy oscillated by said magnetron and being arranged on the outside of said air-tight vacuum envelope.
Claim 3
Dependent Claim
165 words
A magnetron according to claim 1, further comprising an insulating tube fitted around the periphery of said input side insulator and extending from said connection between said input side insulator and said input side sealing metal member, said choke structure comprising a first flanged metal cylinder and a second flanged stepped metal cylinder, said first flanged metal cylinder having a cylindrical portion fitted around the periphery of said insulating tube and extending toward said connection, said cylindrical portion maintaining predetermined spaced relationship with said connection, said second flanged stepped metal cylinder being arranged cocentrically with said first flanged metal cylinder and having a small-diameter cylinder portion forcibly fitted on said input side sealing metal member, said second flanged stepped metal cylinder further having a large-diameter cylinder portion with a diameter larger than the outer diameter of said cylindrical portion of said first metal cylinder, the flange of said second flanged stepped metal cylinder being closely attached to the flange of said first flanged metal cylinder.
Claim 4
Dependent Claim
181 words
A magnetron according to claim 1, further comprising a shield case covering the exterior component elements on the input side of said air-tight cacuum envelope, said shield case having part of the bottom thereof comprising part of said input side sealing metal member, said shield case containing a stepped cup-shaped metal member concentrically arranged with said input side insulator and input side sealing metal member, said stepped cup-shaped metal member having a bottom with a hole through which said input side insulator is passed, said stepped cup-shaped metal member having a large-diameter portion with its inner bottom surface spaced from the inner bottom surface of said shield case, said stepped cup-shaped metal member having a small-diameter portion with its inner bottom surface spaced from the upper surface of said input side sealing metal member, the wall end of said large-diameter portion of said stepped cup-shaped metal member being fixed on the inner bottom surface of said shield case; said choke structure comprising said stepped cup-shaped metal member, part of said shield case and part of said input side sealing metal member.
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) | 1977-11-04 | 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 |