US3406268A - Miniature single pole-double throw ceramic-metal switch structure - Google Patents

Description

Oct. 15, 1968 R. w. HANSEN 3,406,268

MINIATURE SINGLE POLE-DOUBLE THROW CERAMIC-METAL SWITCH STRUCTURE Original Filed April 15, 1965 INVENTOR.

ROBERT W. HANSEN United States Patent 3,406,268 MINIATURE SINGLE POLE-DOUBLE THROW CERAMIC-METAL SWITCH STRUCTURE Robert W. Hansen, San Jose, Calif., assignor to Jennings Radio Manufacturing Corporation, San Jose, Calif., a

corporation of Delaware Continuation of application Ser. No. 448,322, Apr. 15, 1965. This application Nov. 20, 1967, Ser. No. 684,561 4 Claims. (Cl. 200-144) ABSTRACT OF THE DISCLOSURE A single pole-double throw hermetically sealed switch having two axially aligned ceramic envelope portions closed at each opposite end by metallic end caps, one of which constitutes a diaphragm, and having intermediate said metallic end cap assemblies an intermediate electrode. Either one of two selected circuits through the switch is made or broken by an axially extending contact rod pivotally supported on the diaphragm.

This application is a continuation of my copending application Ser. No. 448,322, filed Apr. 15, 1965, which is now abandoned. The benefit of the filing date of said copending application is therefore hereby claimed for this application.

This invention relates to electrical relays, and particularly to a vacuum relay susceptible of miniaturization.

Conventional vacuum switches and vacuum relays nor mally utilize an electromagnetic acutating mechanism which generally forms an integral part of the switch structure. This necessitates that the entire mechanism be relatively large, and at least in those cases that are actuated through electromagnetic means, it requires that the magnetic field penetrate the envelope wall, thus imposing certain restrictions on construction. It is accordingly one of the objects of the invention to eliminate such actuating mechanism as an integral part of the switch structure per se, to thus enable miniaturization of the relay.

In conventional vacuum switches and vacuum relays, it is quite common to find moving parts within the envelope itself. This necessitates that such moving parts he provided with a bearing surface within the envelope, resulting in friction between the moving parts, which in turn leads to wear and eventual destruction or unreliable operation of the switch or relay. Additionally, the provision of such bearing surfaces within the envelope leads to contamination through trapping of acids within the envelope and also undesirable dust-gathering surfaces therewithin. Therefore, it is another object of the invention to provide a miniaturized vacuum relay having contacts within the envelope which may be moved by an actuating device constituting a separate entity outside of the envelope.

In conventional vacuum switches and relays which incorporate an actuating mechanism as an integral part of the switch itself, it is necessary to adjust such switch or relay before it is baked to drive out occluded gases. The bake-out procedure involves the application of high heat to the device, which often causes mis-alignment of the parts due to re-shaping of the metal and sagging of the glass or creep of the metal. It is therefore a still further object of the present invention to provide a miniaturized vacuum relay in which such adjustment as is required is effected after the relay or switch is pumped and out-gassed simply by adjusting the position of the actuator mechanism in relation to the relay.

In conventional vacuum relays and switches which utilize an electromagnetic actuating mechanism forming 3,406,268 Patented Oct. 15, 1968 a part of the envelope, it is usually necesary for the magnetic lines of force to penetrate the envelope wall. This construction results in some magnetic losses in the magnetic circuit, thus reducing the efficiency of the electromagnetic actuator, Therefore, it is a still further object of the invention to provide a miniaturized vacuum relay in which the actuator may be a separate entity with its own magnetic circuit, thus ensuring the efficient operation of the actuator mechanism and relay to which it is connected.

A still further object of the invention is the provision of a miniaturized vacuum relay in which the cost of construction is reduced by virtue of the use of punched metal parts.

It is a still further object of the invention to provide a miniaturized vacuum relay or switch in which shielding means are directly incorporated with the contact means so that con-tact metal splattered from the contact is intercepted and condensed on the shield prior to its impingement on the envelope wall.

Another object of the invention is the provision of a miniature vacuum relay which may be used for 60 cycle alternating current, radio frequency applications or direct current applications in the range of about 5 kv. steady state operation to perhaps 2-4 amperes continuous current-carrying capacity.

One of the limiting factors for the use of conventional vacuum relays in a radio frequency circuit is the presence of inter-electrode capacitance. It is accordingly another object of the invention to provide a contact configuration in which the inter-electrode capacitance is minimized, thus permitting use of the relay at much higher frequencies in the radio frequency spectrum.

When used in direct current circuits, it is important that a switch or relay be isolated from ground so that the actuating mechanism will be safe to handle. Accordingly, a still further object of the invention is a miniaturized vacuum relay which may be ground-isolated.

A still further object of the invention is the provision of a miniaturized relay which may be very conveniently and economically constructed in a single pole-double throw configuration.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be apparent from the following description and the drawings. It is to be understood, however, that the invention is not limited to the embodiment illustrated and described, as it may be embodied in various forms within the scope of the appended claims.

Referring to the drawings:

FIG. 1 is a vertical cross-sectional view, partly in elevation, through the central axis of the miniaturized vacuum relay. The plane of section is indicated by the line 1-1 in FIG. 3.

FIG. 2 is a vertical cross-sectional view taken in the plane indicated by the line 2-2 in FIG. 3.

FIG. 3 is a plan view taken in the direction of the arrow indicated in FIG. 1.

FIG. 4 is a bottom plan view taken in the direction indicated by the arrow 4 in FIG. 2.

In terms of broad inclusion, the miniature vacuum relay of the invention includes a pair of axially aligned tubular dielectric members such as ceramic, closed at remote ends by metallic end caps and having their adjacent ends bonded in a manner to be hereinafter described. Each of the end caps is provided with suitable terminal lead means, and tubulation means are provided in one of the end caps for connection to a vacuum system for evacuating the envelope. The other end cap is in the form of a flexible diaphragm, on which is mounted a rod having a movable contact on the inner end thereof adapted to extend into the inner end of the tubulation, and a displaced portion or jog intermediate the inner end and the diaphragm to form a second movable contact. The transverse movement of the outer end of the movable contact rod outside the envelope effects transverse movement of both the inner and intermediate movable contacts so that the inner movable contact makes and breaks contact with the inside surface of the tubulation, and the intermediate movable contact makes and breaks contact with an intermediately positioned fixed contact. It will thus be seen that the diaphragm end cap forms the fulcrum for the movable contact rod and also forms a conductive part of the circuit. The miniaturized vacuum relay is fabricated in the configuration of a single pole-double throw relay, with fixed terminal plate and fixed contact interposed intermediate the metallic end caps and having an inner perhiphery positioned so as to be engaged by the intermediate movable contact on the actuator or contact rod. It will thus appear that the flexible diaphragm on which the movable contact rod is pivotally mounted forms a common lead or terminal.

In terms of greater detail, the miniaturized vacuum relay of the invention includes an axially aligned pair of elongated tubular dielectric members 2 and 3, preferably ceramic, provided at their remote ends with metalized end edges 4 and 5, to which are hermetically brazed conductive metallic end caps 6 and 7. The end cap 6 is provided with an inwardly extending annular flange portion 8 terminating in a short and rigid cylindrical portion 9 hermetically brazed about the outer peripheral surface of a tubulation 12. The inner open end 13 of the tubulation extends into the envelope, and the outer end 14 of the tubulation is pinched off as shown to provide a hermetic seal.

The end cap 6 is also provided with a radially extending apertured lug portion 16 to which may be connected a conductor leading to a source of electric current. The end cap 6 is preferably fabricated from relatively inflexible heavy gauge copper, in the order of about .030", while the end cap 7 is preferably fabricated from a relatively thinner and flexible material, in the order of about .005".

The end cap 7 will thus possess suflicient flexibility to permit transverse pivotal movement of a longitudinally extending actuator or contact rod 17. The rod 17 is provided with an inner contact end 18 laterally displaced with respect to the axis of the contact rod and extending into the interior of the tubulation 13, while adjacent its outer end 19 the actuator rod extends through a central aperture for-med in the flexible end cap 7 and is hermetically brazed thereto. The actuator rod 17 is preferably fabricated from tungsten, while the diaphragm or flexible end cap 7 is preferably fabricated from a heat resistant yet conductive metal such as an alloy of nickel, copper and iron. and manganese sold under the trademark Monel. End cap 6 with the attached tubulation 12 is preferably fabricated from copper. As with the end cap 6, the end cap or diaphragm 7 is provided with a radially outwardly extending lug 21 for attachment in a circuit.

In the single pole-double throw configuration of the miniaturized vacuum relay illustrated, the adjacent end edges 27 and 28 are metalized to provide for hermetic attachment of an intermediate electrode plate 29 opposite sides of which (as shown) are brazed hermetically between the metalized end edges 27 and 28. The electrode plate 29 is preferably annular in configuration, and is provided adjacent its inner periphery with a cylindrically extending contact and shield portion 31, surrounding the jogged contact portion of the actuator rod 17, which presents a contact surface 32 adapted to make and break a circuit through the cylindrical shield and contact portion 31. The inner open end 13 of the tubulation, which constitutes the first fixed contact, and the cylindrical shield and contact portion 31 are axially aligned and concentrically disposed with respect to the ceramic envelope portions 2 and 3. It will thus be seen that the lug 21, which may either form an integral part of the diaphragm 7 or constitute a separate part brazed thereto as shown, forms the common contact or lead for the normally closed lug 16 and the normally open lead or contact 33. The interiors of the tubulation 12 and shield 31 thus function as spatter shields to prevent the deposition of vaporized contact metal on the interior surfaces of the dielectric envelope portions.

It will thus be apparent that by virtue of a very small amount of transverse movement of the actuator rod outside of the envelope, in the direction indicated by the arrows in FIG. 1, a relatively greater amount of movement is provided inside the envelope to bring the movable contacts into engagement with the respective fixed contacts.

What is claimed is:

1. A single-pole, double-throw switch comprising: first and second dielectric tubes; first means including a first conductive disc hermetically sealed to one mutually adjacent end of each of said tubes, said tubes having a common axis; second means including a second conductive disc hermetically sealed to the other end of said first tube; third means hermetically sealing said other end of said first tube; a flexible diaphragm fixed to the other end of said second tube, each of said discs having a hole therethrough; and a conductive rod fixed relative to said diaphragm in a position projecting upwardly through both of said disc holes, said first and second means acting as contacts for said switch, said rod acting as the pole of said switch, said rod having a straight portion and a bent portion so as to touch only one of said first and second means in one position of said rod and to touch the other of said first and second means in another position of said rod different from said one position, said bent rod portion being integral with said straight portion thereof.

2. The invention as defined in claim '1, wherein said rod extends through the center of said diaphragm and is electrically bonded thereto thereat, said diaphragm also being conductive, said discs having conductive tabs for electrical circuit connections, said second means including a first conductive cylinder fixed to said second disc in a position contiguous to said rod, said first cylinder being electrically connected to said second disc, said first means including a second conductive cylinder integral with said first disc surrounding said hole therethrough, and positioned contiguous to said rod, said cylinders thereby acting both as contacts and as shields to prevent the spray of metal vapor on the walls of said tubes and thereby to prevent short circuits.

-3. The invention as defined in claim 1, wherein said first means includes a conductive cylinder electrically and mechanically fixed to said first disc sunr-ounding said hole therethrough, and positioned contiguous to said rod.

4. The invention as defined in claim 3, wherein said cylinder is an integral part of said first disc.

References Cited UNITED STATES PATENTS 3,154,655 10/1964 Hawkins 200-444 FOREIGN PATENTS 1,337,323 8/1963 France. 571,959 1/1958 Italy.

ROBERT S. MACON, Primary Examiner.

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