US1897337A - Tuning element - Google Patents
Tuning element Download PDFInfo
- Publication number
- US1897337A US1897337A US403526A US40352629A US1897337A US 1897337 A US1897337 A US 1897337A US 403526 A US403526 A US 403526A US 40352629 A US40352629 A US 40352629A US 1897337 A US1897337 A US 1897337A
- Authority
- US
- United States
- Prior art keywords
- shield
- cadmium
- metal
- base
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910052751 metal Inorganic materials 0.000 description 17
- 239000002184 metal Substances 0.000 description 17
- 229910052793 cadmium Inorganic materials 0.000 description 12
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 12
- 239000011248 coating agent Substances 0.000 description 12
- 238000000576 coating method Methods 0.000 description 12
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 11
- 229910052802 copper Inorganic materials 0.000 description 11
- 239000010949 copper Substances 0.000 description 11
- 150000002739 metals Chemical class 0.000 description 5
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910002065 alloy metal Inorganic materials 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0007—Casings
- H05K9/006—Casings specially adapted for signal processing applications, e.g. CATV, tuner, antennas amplifier
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G5/00—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture
- H01G5/38—Multiple capacitors, e.g. ganged
Definitions
- This invention relates to radio devices and more particularly to tuning elements.
- An object of the invention is to shield tuning elements or units of radio sets by providing good contact throughout the entire portion of the shield around certain parts in said tuner.
- Another object is to provide an intermediate coating of metal between metals of different parts in the tuner element which intermediate coating has minimum electrical potential with such metals so as to mini: mize electrolytic action in respect to voltaic couples.
- Fig. 1 is an elevation of a tuning element such as shown in the application of Theodore J .Scofield and William D. Miner filed October 30, 1929, Serial No. 403,530.
- Fig. 2 is a perspective view of the shield over the lower part of the tuning element shown in Fig. 1.
- Fig. 3 is a longitudinal section through the shield shown in Fig. 2.
- Fig. 4 is a fragmentary showing of the contact portions of the metallic base of the tuner, the shield and the coating of metal therebetween.
- the shield for the tuning coils 1, 2, 3 and 4 shown in dotted lines in Fig. 2 and more particularly described in the above referred to application, is of the shape shown in Figs. 2 and 3. It consists of a strip of good conducting metal such as copper bent in U-shape to form the two sides, 5, 6 and bottom 7
- the end 8 has its side and bottom edges bent at 9, 10 and 11 to present welding or soldering surfaces. Preferably these surfaces are spot welded to the U-shape member at various points such as indicated at 12 to make good electrical contact.
- the other end portion 13 is similarly formed and welded to the U- shape member.
- An intermediate shielding partition 14 is shaped similarly to the ends and is spot welded or soldered to the two sides and bottom of the U-sha-pe member in the way that has just been referred to in connection with the end member.
- This central shield 14 completely shields the coils 1 and 2 from coils 3 and 4 when taken in conjunction with the bottom 15 of the tuner element.
- electrolytic action is set up between the positive copper shield and the negative aluminum alloy base 15 of the tuner element. This is because copper and the metals in the alloy form a voltaic couple.
- the passage of electrolytic current across the space between the copper and the alloy metals produces corrosion and increases a resistance at the junction points. Consequently the shielding action is rendered imperfect by the corrosion.
- the electrolytic action produces electrolytic variations in the electrolytic current that produce noises when the set is in operation. These variations become more marked as the corrosion increases.
- the shield box is placed over the coils 1, 2, 3 and 4 in correct position the central shield partition 14 enters the notch 18 in a boss ridge case on the bottom of base 15 of the condenser body.
- the ends 8 and 13 in this position also contact with the bottom of the base 15 and the sides 5 and 6 contact with opposite sides of this base. Screws then are threadeclthrough the holes in sets 5 and 6 and into threaded holes in the base 15 to clamp the cover in position.
- the coating metal may be applied to the base 15 of the condenser without departing'from the spirit of the invention.
- the invention consists in locating a layer of cadmium or other. suitable material between the copper shield and the alloy base of the condenser and as far as the spirit of the invention is concerned it is immaterial whether the ing of a different metal adapted to produce with said metal framean electrolytic couple of predetermined electromotive force and a sheet of still difierent metal integrally joined to one of said members and contacting with the other of said members, the metal of said sheet adapted to produce with said other member an electrolytic couple of materially less electromotive force whereby electrolytic action between said parts is reduced.
- a copper box member In shields for electrical devices, a copper box member, an aluminum alloy top member attached thereto and a coating of cadmium on one of said members separating it from the other memberto prevent direct contact th-erebetween.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Signal Processing (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Description
e If fie/d Feb, 14, 1933. T. J. SCOFIELD TUNING ELEMENT Filed Oct. 30 1929 Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE THEODORE JOHNSON SCOFIELD, OF JACKSON, MICHIGAN, ASSIGNOR TO THE SPARKS- WITHINGTON COIIEANY, A. CORPORATION OF OHIO TUNING ELEMENT Application filed October 30, 1929. Serial No. 403,526.
This invention relates to radio devices and more particularly to tuning elements. An object of the invention is to shield tuning elements or units of radio sets by providing good contact throughout the entire portion of the shield around certain parts in said tuner.
Another object is to provide an intermediate coating of metal between metals of different parts in the tuner element which intermediate coating has minimum electrical potential with such metals so as to mini: mize electrolytic action in respect to voltaic couples.
Further objects will be given in. the following specification, reference being had to the drawing, in which:
Fig. 1 is an elevation of a tuning element such as shown in the application of Theodore J .Scofield and William D. Miner filed October 30, 1929, Serial No. 403,530.
Fig. 2 is a perspective view of the shield over the lower part of the tuning element shown in Fig. 1.
Fig. 3 is a longitudinal section through the shield shown in Fig. 2.
Fig. 4 is a fragmentary showing of the contact portions of the metallic base of the tuner, the shield and the coating of metal therebetween.
The shield for the tuning coils 1, 2, 3 and 4 shown in dotted lines in Fig. 2 and more particularly described in the above referred to application, is of the shape shown in Figs. 2 and 3. It consists of a strip of good conducting metal such as copper bent in U-shape to form the two sides, 5, 6 and bottom 7 The end 8 has its side and bottom edges bent at 9, 10 and 11 to present welding or soldering surfaces. Preferably these surfaces are spot welded to the U-shape member at various points such as indicated at 12 to make good electrical contact. The other end portion 13 is similarly formed and welded to the U- shape member. An intermediate shielding partition 14 is shaped similarly to the ends and is spot welded or soldered to the two sides and bottom of the U-sha-pe member in the way that has just been referred to in connection with the end member. This central shield 14 completely shields the coils 1 and 2 from coils 3 and 4 when taken in conjunction with the bottom 15 of the tuner element.
For reasons described in connection with the above mentioned application it is desira- 65 ble toform a very loose coupling between the coils 1 and 2 and 3 and 4, and therefore a copper or other good conducting metallic shield 16, 17, is placed between these coils. The bent-over sides of these shields 16, 17 are spot welded to the sides of the U-shape member. These shields do not completely extend across the vertical space of the shield box as some coupling between the coils 1 and 2, 3 and 4 respectively, is permitted at the top of the shield 16 and 17. Therefore, it is immaterial whether or not the shielding action is complete at the bottom of the shield 16, 17 and these are not spot Welded to the bottom 7. If there is any leakage of magnetic '0 flux at the base of this shield it will be a useful flux added to that passing through the open space at the top.
I have found that in some cases, particularly where receiving sets are exposed to moisture, electrolytic action is set up between the positive copper shield and the negative aluminum alloy base 15 of the tuner element. This is because copper and the metals in the alloy form a voltaic couple. The passage of electrolytic current across the space between the copper and the alloy metals produces corrosion and increases a resistance at the junction points. Consequently the shielding action is rendered imperfect by the corrosion. Furthermore, the electrolytic action produces electrolytic variations in the electrolytic current that produce noises when the set is in operation. These variations become more marked as the corrosion increases.
I have found that I can minimize and substantially eliminate these electrolytic currents by coating with cadmium the entire upper portions of the shield box that makes contact with the base 15 of the condenser. To accomplish this plating I invert the shield box shown in Fig. 2 and extend it a sufficient depth into a plating solution which plates the sides 5. and 6 and the ends 8 and 13 at the upper portion including the edges. I have stippled the upper portions of the various members to show the location of the cadmium plate at 17'. It is unnecessary to plate shields 16 and 17 because they do not contact with any dissimilar metal. The shield box therefore is not dipped sufiiciently into the cadmium solution to plate those shields.
YVhen the shield box is placed over the coils 1, 2, 3 and 4 in correct position the central shield partition 14 enters the notch 18 in a boss ridge case on the bottom of base 15 of the condenser body. The ends 8 and 13 in this position also contact with the bottom of the base 15 and the sides 5 and 6 contact with opposite sides of this base. Screws then are threadeclthrough the holes in sets 5 and 6 and into threaded holes in the base 15 to clamp the cover in position. I
When the parts are assembled in this way there will be a cadmium coating between the copper and the alloy metal of the base in all portions where there is contact between these metals. This substantially eliminates all electrolytic action.
While I have found that cadmium is a suitable metalfor coating the shield, other metals may be used to accomplish this result and the invention is not limitedto any particular coating metal. I
.While'it is preferable to coat the copper shield box, the coating metal may be applied to the base 15 of the condenser without departing'from the spirit of the invention. The invention consists in locating a layer of cadmium or other. suitable material between the copper shield and the alloy base of the condenser and as far as the spirit of the invention is concerned it is immaterial whether the ing of a different metal adapted to produce with said metal framean electrolytic couple of predetermined electromotive force and a sheet of still difierent metal integrally joined to one of said members and contacting with the other of said members, the metal of said sheet adapted to produce with said other member an electrolytic couple of materially less electromotive force whereby electrolytic action between said parts is reduced.
2. In shields for electrical devices, a copper box member, an aluminum alloy top member attached thereto and a coating of cadmium on one of said members separating it from the other memberto prevent direct contact th-erebetween.
3. In a radio unit, an aluminum alloy base, tuning elements attached thereto, a copper shield surrounding said elements, a cadmium coating on said shield and means to secure said shield to said base with the cadmium in contact therewith. In testimony whereof, I have signed my name to this specification this 22nd day of October," 1929..
THEODORE JOHNSON a SQGFHELD.
coating is applied to the one metal or to the 7 other or even applied between the two in sepbeing taken in what might be called the external circuit and not in the electrolyte. Cadmium on the other hand has a slightly lower potential than hydrogen with a tendency for the so-called external currentto flow into the cadmium. Aluminum is likewise negative in respect to hydrogen but to a much greater 7 extent. Thus there is a greater voltage tending to set up a current in the external circuit a between aluminum and copper. By interposing a coating of cadmium, the potential is lowered'to' the point where disturbing electrolytic currents are absent.
Havingfdescribed the. invention, what I claim is r r 1. In radio units, a metal frame member, a V
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US403526A US1897337A (en) | 1929-10-30 | 1929-10-30 | Tuning element |
FR705464D FR705464A (en) | 1929-10-30 | 1930-10-08 | Improvements in electrical capacitor assembly processes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US403526A US1897337A (en) | 1929-10-30 | 1929-10-30 | Tuning element |
Publications (1)
Publication Number | Publication Date |
---|---|
US1897337A true US1897337A (en) | 1933-02-14 |
Family
ID=23596105
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US403526A Expired - Lifetime US1897337A (en) | 1929-10-30 | 1929-10-30 | Tuning element |
Country Status (2)
Country | Link |
---|---|
US (1) | US1897337A (en) |
FR (1) | FR705464A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2755386A (en) * | 1952-04-09 | 1956-07-17 | Standard Coil Prod Co Inc | Tuner shield |
US2782315A (en) * | 1951-10-16 | 1957-02-19 | Oak Mfg Co | High frequency tuning apparatus |
US3268797A (en) * | 1962-02-22 | 1966-08-23 | Hitachi Ltd | Direct current high voltage power supply |
US3721746A (en) * | 1971-10-01 | 1973-03-20 | Motorola Inc | Shielding techniques for r.f. circuitry |
-
1929
- 1929-10-30 US US403526A patent/US1897337A/en not_active Expired - Lifetime
-
1930
- 1930-10-08 FR FR705464D patent/FR705464A/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2782315A (en) * | 1951-10-16 | 1957-02-19 | Oak Mfg Co | High frequency tuning apparatus |
US2755386A (en) * | 1952-04-09 | 1956-07-17 | Standard Coil Prod Co Inc | Tuner shield |
US3268797A (en) * | 1962-02-22 | 1966-08-23 | Hitachi Ltd | Direct current high voltage power supply |
US3721746A (en) * | 1971-10-01 | 1973-03-20 | Motorola Inc | Shielding techniques for r.f. circuitry |
Also Published As
Publication number | Publication date |
---|---|
FR705464A (en) | 1931-06-08 |
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