US3541484A

US3541484A - Vacuum relay

Info

Publication number: US3541484A
Application number: US786211A
Authority: US
Inventors: Victor E De Lucia
Original assignee: TORR LAB Inc
Current assignee: TORR LAB Inc
Priority date: 1968-12-23
Filing date: 1968-12-23
Publication date: 1970-11-17
Anticipated expiration: 1987-11-17

Description

United States Patent O 3,541,484 VACUUM RELAY Victor E. De Lucia, Los Angeles, Calif., assignor to Torr Laboratories, Inc., Los Angeles, Calif., a corporation of California Filed Dec. 23, 1968, Ser. No.. 786,211 l Int. Cl. H01h 1/18 U.S. Cl. 335--196 8 Claims ABSTRACT F THE DISCLOSURE An improved construction for a miniature vacuum relay is provided. The relay includes an evacuated envelope in which the movable and iixed contacts of the relay are housed. The movable Contact is supported on a magnetic armature within the envelope, in position to make and break selectively with the fixed contacts of the relay. A feature of the relay of the invention is the establishment of a connection from an external terminal to the movable contact by means of a U-shaped resilient spring whose side members extend along both sides of the path of the movable contact, and Whose side members are biased against the movable contact in electrical contact therewith. The design of the relay is such that there is no tendency for the relay to bind or to get into a hung up condition.

BACKGROUND OF THE INVENTION The vacuum relay to be described includes a movable armature and magnetic pole pieces enclosed in an evacuated glass or ceramic envelope. The energizing coil for the relay, and the major part of its magnetic circuit, are mounted externally of the envelope. This construction is advantageous in that the relay responds with high sensitivity to the energizing of its coil, since the magnetic circuit projects directly into the evacuated envelope. The ceramic envelope may be used for high frequency applications, and glass seals are provided to obviate leakage which is often encountered in the prior art ceramic relays.

The vacuum relay of the invention is of the general type which comprises an evacuated chamber formed by the aforesaid glass or ceramic envelope, and which is closed at one end by a metallic end Wall. The magnetizable core of the relay extends through the metallic end wall, and it is used to draw a pivotally mounted magnetic armature in towards the end of the core. The armature is pivotally mounted within the chamber on the inner face of the end wall, and it is normally spring biased away from the end wall.

In the construction of the present invention, an insulating post composed, for example, of sapphire, is staked to the armature, a highly conductive metallic sleeve is fitted over the post, and the movable contact of the relay is formed by a conductive collar which is supported on an under cut end portion of the conductive sleeve at the outer end of the post. The fixed contacts are in the form of conductive pins which extend through the glass envelope of the relay and into the evacuated chamber. These pins are configured so that their ends extend across the path of the movable contact, in front of and behind the movable contact, so as to be selectively contacted thereby as the armature is moved between its two pivotal positions. Both the movable contact and the lixed contacts are preferably formed of a refractory material, such as tungsten or molybdenum for long operational life. The refractory movable contact is backed up by the highly conductive sleeve. The sleeve and movable contact, as Well as the insulating post are all assembled to the armature mechanically and no brazing, welding or soldering is required, so that there is no oxidizing of the components during fabrication.

A connection is made to the movable contact from a third electrically conductive common pin extending through the glass or ceramic envelope. This latter connection has the form of a U-shaped resilient spring, and the movable contact slides between the side members of the spring as the armature moves from one pivotal position to the other. The side members of the spring are resiliently biased against the sides of the aforesaid conductive sleeve so as to maintain a continuous electrical contact with it. The sleeve and U-shaped spring serve to complete the electrical circuit between the movable contact and the common conductive pin.

The construction of the improved miniature vacuum relay of the present invention is advantageous in that no twisting or turning motions of the movable contact assembly are developed in the relay. This is because, as the armature moves from one of its pivotal positions to the other, the movable contact and associated components move with the armature, without any twisting or turning movement, as is the case with most of the prior art relays of the same general type. This obviates any tendency for the relay to bind or to get hung up. Also, this construction enables the relay to exhibit extremely long operational lifetime characteristics. Moreover, the relay of the invention is easy to construct in that the fixed contacts and the U-shaped spring may be mounted in the envelope as a lirst sub-assembly, and the other components may be mounted on the base as a second sub-assembly, with the two sub-assemblies being subsequently joined together by a simple heliarc operation.

The miniature relay to be described is particularly suited for high voltage applications, and it does not exhibit any tendency to deteriorate when used with high voltages and peak currents, even under high ambient temperature conditions. Also, and as described above, the simple movement of the movable contact assembly and armature of the relay obviates any tendency for it to stick or otherwise malfunction during its operation.

iBRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side section of a relay constructed in accordance with the concepts of the present invention;

FIG. 2 is a cross sectional view taken along the line 2-2 of FIG. l; and Y FIG. 3 is a sectional view of the armature sub-assembly of the relay.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT As illustrated in the drawing, the miniature vacuum relay of the present invention comprises an evacuated envelope 10. The envelope may be formed of glass, ceramic or any other appropriate material. The envelope is closed at its lower end by a metallic non-magnetic ring 11 which, together with the envelope 10, and the magnetic structure to be described, define an evacuated chamber in which the operating components of the relay are situated.

A magnetizable core 12 extends through the ring 11, as shown. A magnetic housing 13 surrounds the core, and it has an annular end portion 13a. The end portion 13a, together with the core 12 and ring 11 constitute the end wall for the evacuated chamber. An armature 14 is pivotally mounted within the evaucated chamber on the end portion 13a, for movement towards and away from the inner end of the core 12. An electric coil 16 is mounted externally of the envelope within the housing 13, and it surrounds the core 12. A spring 18 normally biases Nthe armature 114 to the tilted condition shown in FIG. 1.

However, when the coil 16 is energized, the resulting magnetism established in the core 12 draws the armature in against the end of the core against the biasing action `of the spring 16. The end portion 13a is attached to the envelope 10 by means of a ring 19. The ring 19 may be formed of Kovar or other appropriate material. When the envelope is formed of ceramic, a glass frit seal may be used between the ring 19 and the envelope 10` to obviate any tendency to leakage.

An insulating post 20 formed, for example, of sapphire, is staked to the armature 14, and the post extends outwardly from the plane of the armature. The post 20 is surrounded by an electrically conductive sleeve 22 (FIG. 3). This sleeve, for example, may be formed of beryllium copper, or other high conductivity material, and it may be silver plated. The post may be ground to a velvet iinish to provide frictional resistance suicient to hold the sleeve in a press fit relationship therewith.

'I'he movable contact of the relay is in the form of a collar 24 which, as shown in FIG. 3, is tted over the end of the sleeve 20 which may appropriately be under cut to have a reduced outer diameter, as shown. The end of the sleeve 22 is rolled over to hold the collar 24 in place. The collar 2.4 is in electrically conductive relationship withthe sleeve 22, so that the sleeve provides a good high conductive backing for the collar 24. The collar is formed, for example, of an electrically conductive material having high refractory characteristics, such as molybdenum or tungsten, so as to be capable of breaking relatively high currents without deterioration. The movable contact 24 may, if so desired, be formed of a tungsten-rhenium alloy, or a tungsten-rhenium-osmium alloy (70%-20%51%). A feature of the armature-

movable contact assembly

14, 20, 22 and 24 is that it requires no brazing, soldering or Welding for its construction which would tend to oxidize and contaminate the various components. The sleeve 22, as noted, may be composed of high conductive material, such as beryllium copper, and it may be silver plated to provide lubricated sliding contactvcharacteristics for continuous sliding contact with a spring component to be described. A. The fixed contacts of the relay are formed, for example, by a pair of electrically

conductive pins

30 and 32 formed of tungsten or other electrically conductive material of high refractory characteristics. The pins 30= and 32 extend through the envelope 10 into the interior, and the lower ends of the pins are bent over to extend across the path of the movable contact collar 24 in front of and behind the movable contact respectively. The

pins

30 and 32 are positioned so that the pin 30, for example, is engaged by the movable contact collar 24 when the armature 14 is in its tilted position shown in FIG. l, and so that the pin 30 will be engaged by the movable contact collar 24 when the relay is energized to draw the armature 14 against the end of the core 12.

Connection is established to the movable contact collar 24 hy means of a third electrically conductive pin 36 which extends through the top of the envelope 10. A U-shaped spring 38 is axed to the lower end of the pin 36 by spot welding or the like. The spring 38 has a pair of side members which extend parallel to the path of the armature assembly on both sides of the sleeve 22, s0 that the sleeve slides along the inner surfaces of the spring 38. The spring 38 may be formed, for example, of heattreated beryllium copper, and its side members are spring biased inwardly towards one another and against the sleeve 22. The spring 38 also may be silver plated to provide a lubricated continuous sliding contact with the sleeve 22.

The spring biasing tension of the spring is made sufcient so that a positive contact is maintained thereby between the pin 36 and the sleeve 22 even after long operating intervals have produced wear to the aifected parts. The sleeve 22 is in electrically conductive relationship with the movable contact 24, so that electrical connection is established from the pin 36 through the spring 38 and through the sleeve 22 to the movable contact 24. Moreover, a positive and continuous contact is maintained without any tendency for interruption, as the movable contact moves back and forth along its path.

For high frequency uses, and as described above, a ceramic envelope may be used. As also described, when such an envelope is used, glass seals are incorporated, so that the desired electrical characteristics of the ceramic may be utilized in conjunction with the ease and reliability of glass in forming and maintaining vacuum tight integrity in the assembly.

The invention provides, therefore, an improved vacuum relay which is constructed so that it may operate satisfactorily over long periods of time, even in conjunction with extremely high voltages and peak currents, and even under high temperature ambient conditions.

What is claimed is:

1. In a vacuum relay which includes an envelope, a magnetic member mounted on an endv Wall of said envelope and extending into the interior of said envelope, an armature positioned in said envelope pivotally mounted on said end wall, a rst electrically conductive pin extending through the envelope into the interior thereof, and a second electrically conductive pin extending through the envelope into the interior thereof, the combination of: a U-shaped resilient electrically conductive spring mounted in said envelope on said first pin and having a pair of side members resiliently biased inwardly towards one another; and a movable contact means mounted on said armature for sliding movement between said side members of said U-shaped spring along the longitudinal axis of said spring to contact said second pin when said armature is moved from one pivotal position to another,

said spring member maintaining continuous contact with said movable contact for such movement of said armature.

2. The combination defined in claim 1 and in which said second pin is configured to have a bent-over end por tion in said envelope traversing the path of said movable contact to be engaged by said movable contact upon the aforesaid movement of said armature.

3. The combination defined in claim 1 and which includes a third electrically conductive pin extending through said envelope and into the interior thereof, said third pin having a bent-over end portion Within said envelope traversing the path of said movable contacts to be normally engaged thereby and to be disengaged thereby upon the aforesaid movement of said armature.

4. The combination delined in claim 1 and which includes an insulating post mounted on said armature and extending outwardly from the plane thereof, said movable contact being mounted as a conductive collar on the end of said post remote from said armature.

5. The combination defined in claim 4 in which Said insulating post is staked to said armature.

`6. The combination dened in claim 4 and which includes an electrically conductive sleeve mounted on said post in coaxial relationship therewith and electrically connected to said collar, said sleeve engaging said U- shaped spring and completing an electric path between said collar and said lirst pin.

7. The combination defined in claim 6 in which said collar and said second pin are formed of electrically conductive material of high refractory characteristics.

8. The combination defined in claim 1 in which said envelope is composed of a ceramic material, and which includes vitreous seals interposed between said end wall and said envelope and between said pins and said envelope.

References Cited UNITED STATES PATENTS `8/1937 Thomas 174-5063 11/1962 ReXer 174-506 11/1964 Loman 335-196 8/1967 De Lucia 335-260 9/1967 Roessler 335--154 12/ 1967 Wildeboer 174-5061 U .S. C1. XR.