US3275776A

US3275776A - High vacuum miniaturized relay

Info

Publication number: US3275776A
Application number: US394012A
Authority: US
Inventors: Lucia Victor E De
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-09-02
Filing date: 1964-09-02
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27

Description

Sept. 27, 1966 v. E. DE LUCIA HIGH VACUUM MINIATURIZED RELAY Filed Sept. 2, 1964 United States Patent 3,275,776 HIGH VACUUM MINIATURIZED RELAY Victor E. De Lucia, 2051 Pontius Ave., Los Angeles, Calif. Filed Sept. 2, 1964, Ser. No. 394,012 3 Claims. (Cl. 200-144) The present invention relates to vacuum relays, and it relates more particularly to an improved high vacuum relay which is extremely reliable in its operation, and which may be used in applications where performance requirements are especially critical.

'Vacuum relays have achieved wide utility in the relay art, in that deterioration of the relay contacts is reduced to a minimum. This is because the absence of gases in the evacuated envelope of the relay obviates the formation of contact-eroding oxides to a material extent.

However, even in the highest quality prior'art vacuum relays, vaporized metal, released by ion bombardment in the contact areas, has a tendency to form over the contacts and produce welding of the contacts during the operation of the relay. .This means that the contacts of such prior art relays may fail to open when the relay is de-energized.

Contact failure of the type mentioned in the preceding I paragraph cannot be tolerated in many systems in which vacuum relays find general utility. For example, in medical electronics, such relays find utility in heart defribrillator systems, failure of the relays in such systems can cause fatality of the patient.

Likewise, in missile and other space vehicle applications in which the vacuum relays are used to a wide extent, because of their relatively high current-carrying capabilities despite their small size, and because of their ability to withstand high contact voltages; it is most important that any tendency towards contact welding during the operation of the relays be avoided.

The relay of the invention also finds utility in other fields. Some of the additional applications, for example, include switching of pulse networks, and antenna changeover systems, switching in explosive atmospheres, and the general switching of high voltage equipment for ground or airborne systems.

An important object of the present invention, therefore, is to provide an improved vacuum relay which is particularly reliable, and which is particularly suited as a high voltage transfer relay for heart defribrillator systems, and for other applications requiring high quality switching apparatus.

Another object of the invention is to provide such an improved high voltage transfer relay of the vacuum type which is relatively simple and inexpensive to construct.

The improved vacuum relay to "be described achieves long life by the inhibition of the production of vaporized metal in the contact areas by ion bombardment. It is usual invacuu-m relays for the movable contacts to be mounted on an armature composed, for example, of iron or other magnetiz-able material.

Due to the production of ions in the relay, and because of the high voltages involved, ion bombardment of the armature produces vaporized iron which has a tendency to deposit over the contact surfaces. It has been found that even a mono-layer of condensed iron vapor can increase the weldability of the, metals used as contacts in the relay.

The inhibiting action of the relay of the present invention directs the ions to an area away from the contact surfaces, so that the deposition of a metallic film with welding capabilities on the critical contact surfaces is prevented. This action is achieved, as will 'be described, by a focusing action in the relay which causes the ions to be directed into the interior of a chamber of a chamberlike electrode, so that any vaporized metal released by ion bombardment is condensed therein.

The particular type of vacuum relay to be described includes a glass envelope which is evacuated, and which envelope contains the relay contacts and armature of the assembly. A magnetic core assembly and electric energizing coil are contained in a core housing which is mounted externally of the envelope.

A feature of the invention is the provision of a mounting means for the above-mentioned core housing, whereby the glass envelope and its components are removably retained in the core housing. This facilitates the use of the assembly in that it permits convenient replacements to be made in the field, should the glass envelope or its associated components become damaged, or otherwise inoperative.

As will be described, the improved vacuum relay of the invention is constructed to meet high reliability, long life requirements in high voltage, peak current applications. Because of its extremely high vacuum dielectric strength, the vacuum relay of the invention can be made much smaller than usual relays of similar voltage and current ratings.

The high vacuum in the envelope of the relay of the invention, as noted, minimizes contact arcing and maintains the contacts free from oxidation so as to insure stable and low contact resistance. In addition, and as will be described, the vacuum relay of the invention is constructed so that ion bombardment takes place in a chamber away from the critical contact surfaces, so as to preclude the formation of weldable metal condensates on the contact surfaces.

Other objects and advantages of the invention will becomeapparent from a consideration of the following description, when the description is taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a perspective view of an improved vacuum relay constructed in accordance with the concepts of the present invention;

' FIGURE 2 is a fragmentary perspective view illustrating the manner in which the evacuated envelope portion for use in the evacuated envelope;

FIGURE 7 is a side view of the assembly of FIGURE 6, taken substantially on the line 7'7 of FIGURE 6; and

FIGURE 8 shows a fixed contact rod which is used in the assembly of FIGURE 1.

The improved vacuum relay of the invention, in the embodiment disclosed in the accompanying drawing, includes an evacuated envelope 10 formed of glass, for example, or other suitable vitreous or other material. I'he evacuated envelope 10, in the illustrated embodiment, has a T-shaped configuration, so as to have a'p-air of aixally aligned housing portions 12 and 14, and a transverse housing portion 16.

A first fixed contact rod 20 extends into the housing portion 12 of the envelope 10. The contact rod 20 may 'be formed, for example, of tungsten, or any other suitable electrically conductive material. One end of the rod 20 is sealed to the envelope 10 by means of a usual bead 21.

A second contact rod 22 (see also FIGURE 8) extends into the housing portion 14 of the envelope 10 in axially aligned relationship with the rod 20. The rod 22 is axially spaced from the rod 20 within the envelope 10. The rod 22 may be composed of tungsten, for example, and it is sealed by an appropriate bead 23 to the envelope 10 at the end of the housing portion 14.

A third electrical contact rod 24 (see also FIGURES 6 and 7) extends into the housing portion 16 of the envelope 10. The rod 24 may also be composed of tungsten. The axis of the rod 24 extends transversely of the common axis of the rods 20 and 22, and the former axis transverses the common axis at a point between the inner facing ends of the two rods 20 and 22. The rod 24 is sealed, by an appropriate vitreous seal 25, to the envelope 10 at the end of the housing portion 16.

An armature 26 (see also FIGURES 6 and 7) is mounted on one end of a thin elongated member 28. The other end of the elongated member 28 is brazed, or otherwise attached, to the inner end of the contact rod 24 by a nickel br-aze 29, for example.

The resilient member 28 may also be composed of tungsten. The rod 24, as noted above, is sealed to the evacuated envelope 10 by means of the bead 25-. The bead 25, as well as the beads 21 and 23, may be composed, for example, of an appropriate grade glass, and the seal between the contact rods and their respective beads is made in accordance with any usual known sealing technique.

As mentioned above, the armature 26 is composed of a magnetizable material, such .as iron. A pair of contact buttons 34 are mounted on the magnetic armature 26 in position .to engage selectively the inner ends of the contact rods 20 and 22. These contact buttons may be composed, for example, of tungsten.

In a constructed embodiment of the invention, the magnetic armature 26 is coated with a nickel layer and with a subsequent gold coating. The tungsten buttons 34 are then temporarily atlixed in position on the coated armature, and the assembly is placed in an oven. The assembly is heated in the oven until the gold coating assumes a molten condition to flow and provide an adhesive means for the cont-act buttons 34. The gold coating also provides an appropriate electrical contact between the contact buttons 34 and the contact rod 24.

As best shown in FIGURES 4 and 5, the contact rod 20 has a tubular member 38 mounted on its free end, the tubular member 38 being in coaxial relationship with the terminal rod 20. The tubular member 38 is composed of magnetizable material, such as iron. As shown clearly in FIGURES 4 and 5, the tubular member is aflixed to the rod 20 solely at its free end, this being achieved by a crimping action.

For example, and as shown in FIGURE 4, the contact rod 20 is equipped with a peripheral channel 20a adjacent its inner end. The tubular member 38 is provided with an end Wall 38a which is positioned to engage the peripheral channel 20a, when the tubular member 3-8 is in place on the contact rod 20. The tubular member is then mounted on the contact rod by crimping the end Wall 38:11 into the peripheral channel 20a by external crimps 38b (FIGURE The construction of the assembly of FIGURES 4 and 5 expedites the construction of the assembly, in that it permits both the

components

20 and 38 to be chemically cleaned at the outset, and then to be mounted together without the need for brazing or the application of heat. This permits the materials to retain a desired malleable consistency. This crimping action also permits the components to be precisely positioned in the envelope, and it obviates any requirement for a subsequent cleaning operation.

Also, the manner in which the tubular member 38 is mounted on the contact rod, solely by the crimping of the end wall 38a into the peripheral channel 20a provides a minimum contact between the tubular member 38 and the rod 40, so that there is no tendency for the tubular member 38 to form a heat sink for any heat introduced into the rod 20.

It will be appreciated that the end wall 38a of the tubular member 38 is displaced inwardly from the inner end thereof. The end wall 38 defines an annular channel or groove about the inner end of the contact rod 20, as best shown in FIGURE 3.

The configuration of the assembly of FIGU-RES 4 and 5 is such that the ions produced in the evacuated envelope 10 are directed down into the aforesaid annular channel, and the resulting vaporized metal produced due to ion bombardment condenses down in the channel, rather than on the critical contact surfaces, such as the inner end of the contact rod 20, or on the movable contacts 34.

As best shown in FIGURE 1, the resilient member 28 normally biases the armature 26 against the inner end of the contact rod 22. In the illustrated embodiment, the vacuum relay is a single-pole, double-throw type. In the above-mentioned initial operating condition of the relay, a normally-closed connection is established between the contact rods 22 and 24.

The housing member 12 of the envelope 10 is supported in a cylindrical core assembly 40, and this core assembly includes the usual apertured mounting member 42 which permits the entire relay to be conveniently mounted on an appropriate panel, or other supporting surface.

The core assembly 40 includes an inner tubular membar which is formed of magnetizable material, and it also includes an outer tubular member which is also formed of magnetizable material. The inner and outer tubular members may be composed, for example, of iron. These tubular core members are mounted in nested concentric relationship, and the usual electric energizing coil is wound between the two members.-

The core assembly 40 also includes a disc-shaped member mounted at one end of the assembly which, likewise, is composed of a magnetizable material, such as iron. This disc-shaped member serves to enclose one end of the assembly, and to complete the magnetic circuit between the inner and outer tubular core members. The assembly also includes a second disc-shaped member at the opposite end which is composed of non-magnetizable material, such as copper or brass.

A shoe member 60 is afiixed to the magnetic core assembly 40. This shoe member has an arcuate shape, and it is adapted to extend partially around the housing portion 16, as shown in FIGURES 1 and 2. The shoe member serves as a support for holding the housing portign 12 of the envelope 10 in place in the core assembly 4 The housing portion 12 of the envelope 10 extends through the central aperture in the cylindrical core assembly 40, and the envelope 10 can be readily removed from the core assembly. When the housing portion 12 is inserted in the core assembly, the envelope 10 is turned until the housing portion 16 extends between the ears of the arcuate-shaped shoe member 60.

A removable clip 70 of resilient material extends around the housing portion 16 of the envelope 10, and has a pair of legs 70:: (FIGURE 2) which extend under the shoe 60, releasably to hold the envelope in place in the core assembly.

It will be appreciated that whenever the envelope 10, or its internal components, become damaged; a simple replacement may be made, merely by withdrawing the clip 70 and removing the envelope from the core assembly. Then, the replacement may be slipped into place, and the clip 70 again inserted with its legs extending under the shoe member 60.

It will be observed that the tubular member 38 of magnetizable material is coaxial with the core assembly 40 and that it lies closely adjacent the inner tubular member of the core assembly. It will also be observed that the shoe 60, which may be composed of magnetizable material, surrounds the armature 26, which, likewise, is formed of magnetizable material.

Now, when the energizing coil in the core assembly 40 is energized, the resulting field from the core assembly causes the armature 26 to be drawn towards the end of the contact rod 20, so that one of its movable contacts 34 engages the inner end of that contact rod. During this latter operational condition of the relay, a connection is established between the contact rod 24 and the contact rod 20.

Therefore, the disclosed embodiment of the invention comprises the single-pole, double-throw vacuum relay. In its normal operational condition, one of the contacts 34 of the armature 36 is biased with a relatively high spring force against the inner end of the contact rod 22. Then, when the relay coil is energized, the other contact 34 on the armature 26 is moved, and held against the inner end of the contact rod 20 with relatively high force.

During the operational life of the relay, any ions generated within the interior of the envelope are directed toward the annular channel at the end of the tubular member 38, and these ions are caused to bombard the surface 38a at the bottom of the aforesaid peripheral channel. The resulting metallic iron vapor is caused to condense and deposit on the walls of the peripheral channel, and the vapor is kept clear of the contact surfaces, as mentioned above.

The invention provides, therefore, an improved relay construction, which is not only relatively simple and inexpensive to fabricate, but which is also convenient to handle and readily receptive to replacement, and one which is capable of operating for long periods of time without any significant contact deterioration, and without any tendency toward contact welding.

While a particular embodiment of the invention has been shown and described, modifications may be made, and it is intended in the claims to cover all modifications which fall within the scope of the invention.

What is claimed is:

1. A vacuum relay including: an evacuated envelope; at first electrical contact rod extending into said envelope; a tubular member of magnetizable material coaxially mounted on said electrical contact rod and extending along at least a portion of the axial length of said contact rod, said tubular member having an inner surface spaced radially from said contact rod; an armature of magnetizable material mounted in said envelope in position to extend transversely of the longitudinal axis of said contact rod adjacent the inner end of said contact rod; movable electrical contact means mounted on said armature selectively to engage the inner end of said contact rod; a core member of magnetizable material removably mounted externally of said envelope in coaxial relationship with said tubular member; an electric energizing coil mounted in said core member for establishing a magnetic flux in said envelope; an arcuate-shaped shoe member mounted on said core member and partially surrounding a portion of said envelope to support said core member on said envelope; and a removable clip means retained by said shoe member for holding said envelope in said core member.

2. The vacuum relay defined in claim 1 and which includes a transverse end wall formed at the inner end of said tubular member and displaced inwardly from said inner end to define an annular channel with said contact rod.

3. The relay defined in claim 1 in which said evacuated envelope has a T-shaped configuration, and which includes a second electrical contact rod axially aligned with said first rod and extending into said envelope from the opposite end thereof and having an inner end spaced from the inner end of said first :rod; a third electrical contact rod extending from said envelope along an axis traversing the axis of said first and second rods; a resilient electrical conductive member supporting said armature on said third contact rod in position to extend between the inner ends of saidfirst and second contact rods and for resiliently biasing said armature against the inner end of one of said first and second contact rods; and in which said electrical contact means selectively engages the inner ends of said first and second electrical contact rods as said electric energizing coil is energized and de-energized.

References Cited by the Examiner UNITED STATES PATENTS 1,998,822 4/1935 Ronci et al 200-87 2,326,074 8/1943 Slepian 200-l44 2,360,941 10/1944 Eitel et a1. 200-87 2,904,729 9/1959 Harwood 336-197 3,082,389 3/1963 Settles et al. 336l74 FOREIGN PATENTS 839,083 6/1960 Great Britain.

ROBERT K. SCI-IAEFER, Primary Examiner.

ROBERT S. MACON, Examiner.

Claims

1. A VACUUM RELAY INCLUDING: AN EVACUATED ENVELOPE; A FIRST ELECTRICAL CONTACT ROD EXTENDING INTO SAID ENVELOPE; A TUBULAR MEMBER OF MAGNETIZABLE MATERIAL COAXIALLY MOUNTED ON SAID ELECTRICAL CONTACT ROD AND EXTENDING ALONG AT LEAST A PORTION OF THE AXIAL LENGTH OF SAID CONTACT ROD, SAID TUBULAR MEMBER HAVING AN INNER SURFACE SPACED RADIALLY FROM SAID CONTACT ROD; AN ARMATURE OF MAGNETIZABLE MATERIAL MOUNTED IN SIAD ENVELOPE IN POSITION TO EXTEND TRANSVERSELY OF THE LONGITUDINAL AXIS OF SAID CONTACT ROD ADJACENT THE INNER END OF SAID CONTACT ROD; MOVABLE ELECTRICAL CONTACT MEANS MOUNTED ON SAID ARMATURE SELECTIVELY TO ENGAGE THE INNER END OF SAID CONTACT ROD; A CORE MEMBER OF MAGNETIZABLE MATERIAL REMOVABLE MOUNTED EXTERNALLY OF SAID ENVELOPE IN COAXIAL RELATIONSHIP WITH SAID TUBULAR MEMBER; AN ELECTRIC ENERGIZING COIL MOUNTED IN SAID CORE MEMBER FOR ESTABLISHING A MAGNETIC FLUX IN SAID ENVELOPE; AN ARCUATE-SHAPED SHOE MEMBER MOUNTED ON SAID CORE MEMBER AND PARTIALLY SURROUNDING A PORTION OF SAID ENVELOPE TO SUPPORT SAID CORE MEMBER ON SAID ENVELOP; AND A REMOVABLE CLIP MEANS RETAINED BY SAID SHOE MEMBER FOR HOLDING SAID ENVELOPE IN SAID CORE MEMBER.