US3021408A - Coaxial switch - Google Patents

Description

Feb. 13, 1962 J, E, JENNlNGs 3,021,408

COAXIAL SWITCH Filed May 18, 1959 IN V EN TOR. 1/0 E MME TT JENN/NGS h/ls AT TORNE Y 3,021,408 COAXIAL SWITCH Jo Emmett Jennings, San Jose, Calif., assignor, by mesne assignments, to'Jennings Radio Manufacturingv Corporation, San Jose, Calif., a corporation of?k Delaware Filed May 18,1959, Ser. No. 813,935 11 Claims. (Cl. 200-144) I Still another object of the invention is the provision i of a vacuum coaxial switch operable remotely by an external solenoid utilizing any practical A.C. or D.C. voltage. n

n Still another object of the invention is the provision of a vacuumcoaxial switch of substantially 5 kw. ca-

pacity and of extremely small size in comparison with conventional coaxial switches having comparable power ratings. g

A still further object of the invention is the provision of a vacuum coaxial switch requiring minimum power to operate, and constructed from materials and in a manner requiring little machining and custom processing so as to maintain manufacturing costs at a minimum.

The invention possesses other objects some of which with the foregoing will be brought out in the following description of the invention. I do'not limit myself to the showing made by the said description and the drawings, since I may adopt variant forms of the invention within the scope of the appended claims.

Referring to the drawings:

FIG. 1 is a vertical half-sectional view, partly in elevation, showing ythe switch contact in its normal springclosed position. The solenoid-closed position of the switch contact is shown in dash lines.

FIG. 2 is a horizontal sectional view taken in the plane indicated by the line 2-2 of FIG. 1.

FIG. 3 is a vertical sectional view taken in the plane indicated by the line 3--3 of FIG. l. Y

FIG. 4 is a fragmentary sectional view illustrating a modified contact structure. f

All of the figures are drawn approximately four actual size.

Broadly considered, the miniature vacuum coaxial switch of my invention comprises a vacuumized envelope including an outer metallic conductor or hermetically sealed shell. Arranged within the outer'conductive shell and rigidly supported thereon are a plurality of inner' conductors which extend hermetically through the envelope wall and provide spaced contact points within theenvelope and terminal leads outside the envelope. The outer metallic shell is preferably cruciform in shape sjo as lto accommodate two axially aligned and spaced transversely extending contact points perpendicular to and spaced from a third common contact point, all of which are insulated from each other and from the conductive outer shell, and each of which is integrally continuous with Aan inner conductor. Mounted within the envelope adjacentfthe three contact points is a mobile contact. The mobile contact is movable from outside contact from outsidethe envelope to make or break acircuit through a selected pair of inner conductors.

In more rspecific detail, the miniature vacuum coaxial switch of my invention comprises a vacuumized envelope formed from an elongated hollow cylindrical metallic shell or tube 2 diametrically apertured intermediate its yends to accommodate axially aligned cylindrical conductive terminal sleeves 3. Each sleeve is formed with a reduced diameter portion 4 extending into the shell 2 through an aperture, and a relatively larger integral terminal portion 6 extending from the shell and provided with threads 7 adapted to receive a conventional coaxial connector (not shown), for connection of the switch in a coaxial transmission line. Each of the aligned terminal sleeves is hermetically brazed to the shell within the aperture so that a mechanically rigid'and electrically continuous union is formed therebetween. The oppositely extending terminal sleeves 3 and shell 2 thus form an integral cruciform outer metallic conductor which completely shields the interior of the envelope from undesirable radiations.

times the envelope to make or break a circuit between a sey contact are provided to effect movement of the mobile iExtending into one end of the cylindrical shell 2 and rigidly brazed thereto is a third terminal sleeve 8 having an inner end portion 9 of the same diameter as the portion 4 of each terminal sleeve 3. A reduced diameter cylindrical portion 12 integral with the inner end portion 9 and with the outer threaded terminal portion 13, fits snugly within the open end of the shell where it is rigidly and hermetically brazed.

Coaxially associated with and supported on each terminal sleeve 3 is `an inner conductor 14 extending through the central aperture of an annular insulator 16 interposed transversely between the inner conductor and the conductive terminal sleeve 3. The insulator 16 is preferably a ceramic annulus having inner and outer peripheries 17 and 18 metallized and hermetically braz'ed to the inner conductorand terminal sleeve, respectively. Each inner ,conductor thus provides an inner end 19 constituting sociated with and supported on the third terminal sleeve 8, by an annular ceramic insulator 23 having an outer metallized periphery 24 hermetically brazed across the reduced diameter portion 12 of the sleeve, and an inner metallized periphery 26 hermeticallybrazed about the inner conductor 22. The outer yend portion 27 of the conductor 22 constitutes a terminal lead extending out of the envelope, while the inner end 28 of the inner conductor extends into the envelope between the inner ends19 of the conductors 14 to provide a fixed contact point common to both contact points 19. As shown in FIG. l, the common contact point 28 is shaped to provide flat contacting surfaces 29 on opposite sides thereof, each parallel to the associated end of the contact point 19.

From the aboveitwill be apparent that the sleeves 3 and 8, annularinsulators 16 and 23, and inner conductors 14 and 22, cooperate one with the other and collectively with thev shell 2, to hermetically close this end of the envelope. The cooperative combination of these elements also provides threeseparate switch terminals having inner and outer conductive elements coaxially arranged and integrally connected mechanically to give rigidity, while effectively electrically insulating the inner conductors one kfrom the other and from the outer conductor. The inner conductor 22 constitutes the common input terminal of the switch, and is related to surrounding structure in both pro-portion and position to maintain a uniformly low standing-wave-ratio through the switch.

Means are provided to hermetically seal the end of the shell 2 opposite the terminal sleeve 8, and to connect and disconnect the common contact point 28 with a selected adjacent contact point 19. Closing the lower end of the shell 2 is a ilexible metallic bellows 31 extending into the shell 2 in a closed inner end 32, and at its outer open end 33 having a cylindrical ange 34 lying snugly within the shell adjacent the end thereof and hermetically brazed thereto.

integrally united at its inner end 36 to the closed inner end 32 of the bellows and extending outwardly therefrom is a metallic stem 37. Adjacent its outer end portion 38, the stem is provided wtih an integral bearing 39 bored transversely of the stem to receive a pivot pin 41 having opposite end portions 42 journaled in the annular bearing mounting plate 43. Spaced lugs 44 on the bearing mounting plate abut opposite ends of and conne the stem bearing 39 to restrict movement thereof to pivotal movement in a single plane including the axes of the inner conductors i4 and 22. A cylindrical sleeve 4b brazed to the periphery of the bearing mounting plate serves to confine the pivot pin 41, and also extends beyond the mounting plate in a ange 47 snugly encircling and brazed about the lower end of the shell 2. Pivotal movement of the outer end 3S of the stem about the pivot pin 4l thus results in the inner end 36 of the stem, with bellows attached, being displaced from side to side within the envelope.

Movably mounted within the envelope on the inner closed end of the bellows is a U-shaped mobile contact having spaced resilient contact arms 48 integral with a base 49 which is in turn brazed to a metal cap 51 similarly brazed on the metallized upper end portion of a dielectric pillar or post 52. A metal cap 53 brazed to the metallized lower end of the post and to the closed inner end or. the bellows insures a rigid and permanent mounting for the U-shaped mobile contact. The dielectric post is preferably high dielectric strength ceramic, and serves to effectively insulate the mobile contact from the operating mechanism.

In FIG. l, the resilient arms 43 are shown to extend upwardly, one each extending between the common contact point 2S and the contact point 19 on each side thereof. The parts are proportioned so that when one of the arms 4S engages the contact point 19 with which it is associated, the other contact arm 4S engages the common contact point 2S, thus completing a circuit therebetween. Movement of the mobile contact in the opposite direction results in the resilient arms being disengaged from the position shown and re-engaged between the common contact point 23 and the other contact point i9. in either position a portion of the mobile contact lies interposed between the engaged contact points and the disengaged contact po-int.

In the modified mobile contact structure illustrated in FlG. 4, each resilient arm 4% is provided on its upper end with an integral contact portion 54 adapted to engage and disengage the associated contact point 19. integrally interposed between each contact portion 54 and the associated surface 29 of common contact 28, is a flexible and conductive metallic bellows 56. This integral interconnection results in the contact resistance being substantially halved, and the inductance being materially lessened. Additionally, interposition of the bellows makes it possible to reduce the spacing between each contact portion 54- and the associated iixed contact point, thus rendering the switch faster acting. Also favorably affected is the standing-wave-ratio through the switch.

Means are provided outside the envelope operatively .connected with the stem 37 to selectively move the mobile contact into and out of engagement with the fixed contact points. schematically illustrated in FIG. l is a solenoid 57, having its armature 58 connected by links 59 to the outer end portion 38 of the stem. A recovery spring 6l connected with the armature and links, retains the mobile contact normally closed as shown. Energizing the solenoid causes the stem to be pivoted counterclo-ckwise about the pin 4i, thus tensioning the spring, which returns the mobile contact to its initial position when the solenoid is deenergized.

Evacuation of the rigid, hermetically sealed envelope is effected through tubulation 62 brazed over an aperture 63 in the shell 2. From the manner in which the stem 37 and bellows are cooperatively related it will be apparent that inward expansion of the bellows due to evacuation of the envelope is prevented by the stem, but due to its inherent flexibility, the inner end of the bellows is capable of being displaced from side to side. Because of its length in relation to the amount of lateral displacement, the stress and strain imposed on the bellows are negligible, thus contributing to a long bellows and switch life.

l claim:

l. A miniature vacuum coaxial switch comprising a vacuumized envelope including the outer metallic conductor of the switch, a plurality of inner conductors rigidly supported on the envelope and extending thereinto to constitute spaced contact points within the envelope and terminal leads outside the envelope, a mobile contact within the envelope movable from outside thereof to engage or disengage selected contact points, said mobile contact having portions thereof so positioned with respect to said contact points on the conductors that movement of the mobile contact to engage selected contact points shieldingly interposes one of said portions of the mobile contact between the engaged contact points and a disengaged contact point whereby power leakage to the disengaged Contact point is prevented, and actuator means mounted on the envelope and operatively connected to the mobile contact to effect movement thereof to make or break a circuit through selected inner conductors.

2. The combination according to claim l, in which said actuator means includes means insulating the mobile contact from the outer conductor.

3. The combination according to claim l, in which said actuator means includes a stem pivotally mounted on the envelope, a flexible metallic bellows integrally interposed hermetically between the stem and the outer conductor, and means for insulating said movable contact from said stem and bellows.

4. A miniature vacuum coaxial switch comprising a vacuumized envelope including an outer metallic conductor constituting a hollow cruciform housing having at least three integral outer terminals, an inner conductor rigidly supported on the envelope and coaxially associated with each outer terminal and extending into the envelope to constitute spaced contact points within the envelope and terminal leads outside the envelope, a mobile contact within the envelope movable from outsidethereof to engage or disengage selected contact points, said mobile contact having portions thereof so positioned with respect to said contact points on the conductors that movement of the mobile contact to engage selected contact points shieldingly interposes one of said portions,Y

interposed between each said inner conductor and theV connected to the mobile contact to effect movement there-` of to make or break a circuit through selected inner conductors. p f

7. The combination according to claim 6, in which extending into the shell intermediate its ends, a third integral outer terminal vsleeve extending into one end of fthe shell perpendicular to the irst and second terminal sleeves, inner conductors coaxially arranged within the outer terminal sleeves and extending ,into'r theV shell to provide spaced contact points within the shell and terminal leads outside the shell,pan annular insulator integrally interposedhermetically between each inner conductor and the associated terminal sleeve, a mobile'contact within the shell U-shaped to provide spaced resilient contact arms extending between adjacent contact points electrically conductive and'llexiblemeans are provided Y for insulating said mobile contact from said stern andy bellows.

10. The combinationaccording to claim 9, in which said means for insulating the mobile contact from the stem and bellows comprises a ceramic post interposed between the mobile contact and the bellows.

11. A miniature vacuum coaxial switch comprising an elongated metallic-vacuumized shell having first and second integral transversely extending outer terminal sleeves points.

References Cited in the tile of this patent y UNITED ySTATES PATENTS Re.21,087 Y Rankin May 16,1939 1,784,302 Millikan et al. Dec. 9, 1930 1,804,086 Brodt May 5, 1931 Y 2,128,427 Means Aug. 30, 1938 f 2,235,010 Chaffee; Mar. 18, 1941 2,527,475 Bates Oct. 24, 1950 2,794,087 Jennings et al. May 28, 1957 r2,920,168 Jennings r Jan. 5, 1960 FOREIGN PATENTS y 115,662 Australia Aug. 4, 1942 n 476,430 Great Britain Dec. 8, 1937 209,454k Sweden July 1, 1940 791,123 Great Britain Feb. 26, 1958 264,433 Sweden Ian. 16, 1950 715,392 Great Britain Sept. 15, 1954 ymentV thereof to engage and movable to engage or disengage selected contact points to make or break a rcircuit therebetween, and

actuator means movably mounted on the shell and operatively connected tothe mobile contact to effect moveor disengage selected contact

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