Title:
SEALED CONTACT RELAY ASSEMBLY
United States Patent 3763449


Abstract:
A sealed contact relay assembly includes a resilient ferromagnetic reed, and a nonmagnetic reed having relatively high electrical conductivity, which extend through opposite ends of a sealed nonmagnetic envelope and which have slightly overlapped inner contact portions within the envelope. A ferromagnetic member is mounted outside the envelope such that energization of a coil produces magnetic forces of appropriate polarity in the resilient ferromagnetic reed and the ferromagnetic member so as to cause the inner contact portion of the ferromagnetic reed to disengage from, or engage with, the inner contact portion of the nonmagnetic reed, depending upon their initial relative positions. The sealed envelope is positioned in a spool on which the coil is wound, and the opposite ends of the spool are filled with nonmagnetic encapsulating material to anchor the envelope and projecting portions of the reeds in fixed positions.



Inventors:
KIMBALL D
Application Number:
05/306031
Publication Date:
10/02/1973
Filing Date:
11/13/1972
Assignee:
WESTERN ELECTRIC CO INC,US
Primary Class:
International Classes:
H01H51/28; (IPC1-7): H01H51/28
Field of Search:
335/151-154
View Patent Images:
US Patent References:
3711749REED SWITCH1973-01-16Koblents
3602851MAGNETIC TIME DELAY SWITCH1971-08-31Wiegand
2922856Electromagnetic switch1960-01-26Karrer



Primary Examiner:
Envall Jr., Roy N.
Claims:
What is claimed is

1. In a contact controlling device:

2. A relay assembly, which comprises:

3. A relay assembly, as recited in claim 2, in which:

4. A relay assembly, as recited in claim 2, in which:

5. A relay assembly, as recited in claim 2, in which:

6. A relay assembly, as recited in claim 2, in which:

7. A relay assembly, as recited in claim 2, in which:

8. A relay assembly, as recited in claim 2, in which:

9. A relay assembly, as recited in claim 2, in which the relay assembly is of a sealed contact type and in which:

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a sealed contact type relay assembly, and more particularly to a sealed contact type relay assembly having a magnetizable element which is mounted outside an envelope and which is selectively magnetized to cooperate with a selectively magnetized contact element within the envelope to effectuate rapid contact make or break action in the relay.

2. Description of the Prior Art

A sealed contact of the type used extensively in telephone communications equipment includes two ferromagnetic reeds which extend through opposite ends of an elongated glass envelope. The reeds have outer cylindrical wire portions which project from the opposite ends of the envelope for connection into a circuit, and inner flattened portions which are sealed in the envelope in a slightly pressurized atmosphere of forming gas (nitrogen and hydrogen), with inner end portions of the reeds in slightly overlapped, spaced relationship. In use, the sealed contact is mounted on an electrical coil of a relay assembly, singly or in combination with other sealed contacts, to achieve different types of switching functions.

At the present time, a standard method of utilizing these sealed contacts in a "break-make" relay is to mount two of the contacts in side-by-side relationship within a spool having a coil wound thereon. A permanent magnet is installed adjacent one of the sealed contacts, saturated magnetically, and then degaussed back to a preselected field strength, so as to create a magnetic field which causes the reeds of the sealed contact to remain normally closed without the use of electrical power. When current of proper direction and magnitude subsequently is passed through the coil, the current creates an electromagnetic field which neutralizes or opposes the magnetic field of the permanent magnet, causing the reeds of the sealed contact to open or "break" electrical contact. At the same time, the electromagnetic field produced by the coil causes the normally open reeds of the second sealed contact to close or "make," thereby achieving a "break-make" function in the associated electrical circuitry. A disadvantage of this relay arrangement, however, is that the permanent magnet, the assembly thereof into the relay, and the saturating and degaussing of the magnet, all increase the cost thereof. Further, since both reeds are of ferromagnetic material, and thus have relatively high electrical resistance, the relay has a relatively high operating power level when installed in an electrical circuit, which is particularly disadvantageous in electronic circuit applications in which it is desired to keep power requirements as low as possible.

Another known device for performing a "break-make" switching function is disclosed in the U.S. Pat. No. 2,397,123, issued Mar. 26, 1946, to J. T. L. Brown. This patent discloses a sealed contact in which a spring-mounted armature piece, two ferromagnetic contact members and a nonmagnetic contact member are all mounted within a glass envelope. The armature piece is normally engaged with the nonmagnetic contact member. Upon energization of an external associated coil, the armature piece moves away from the nonmagnetic contact member to "break" electrical contact therewith, and bridges a gap between the two ferromagnetic contact members to establish or "make" electrical contact therebetween. A disadvantage of this device, however, in addition to its relatively complicated construction, is that in its "make" state of operation, two contact members which are of ferromagnetic material, and which thus have a relatively high electrical resistance, are connected in series. As a result, as in the first relay discussed above, this type of relay also has a relatively high operating power level when installed in an electrical circuit.

Similarly, in the U.S. Pat. No. 3,174,008, issued Mar. 16, 1965, there is shown a sealed contact relay having two ferromagnetic reeds mounted within a glass envelope, and an adjustable reluctance path diverting ferromagnetic member positioned externally of the glass envelope. Reed contact action is attained by inducing magnetic poles in the reeds, the external ferromagnetic member being merely for the purpose of controlling the strength of the magnetic poles to adjust the response time of the relay. It also is known in the prior art to use externally mounted permanent type ferromagnetic members, such as remendur plates, to control reed action in sealed contact switches.

SUMMARY OF THE INVENTION

In accordance with this invention, two elongated, selectively magnetizable ferromagnetic elements are simultaneously magnetized so that magnetic forces are induced in the elements and they repel or attract each other to effectuate movement of one of the elements relative to a nonmagnetic contact element within an envelope of a device such as a relay. More specifically, a relay assembly includes a resilient selectively magnetizable ferromagnetic contact member and a nonmagnetic contact member of relatively high electrical conductivity. The contact members extend through sections of a nonmagnetic envelope and have overlapping inner contact portions within the envelope. A selectively magnetizable ferromagnetic element is mounted outside of the envelope in spaced relationship with respect to the inner contact portion of the resilient ferromagnetic contact member so that upon energization of a coil, magnetic forces are produced in both the resilient ferromagnetic contact member and the ferromagnetic element, to cause the inner contact portion of the ferromagnetic contact member to move relative to the ferromagnetic element and the inner contact portion of the nonmagnetic contact, to change the electrical state of the relay assembly.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1, 2, 3 and 4 are schematic representations of several different types of sealed contacts in accordance with the invention;

FIG. 5 is a cross-sectional view showing a sealed contact as shown in FIG. 1, incorporated into a relay assembly; and

FIG. 6 is a cross-sectional view of the relay assembly of FIG. 5, taken along the line 5--5 in that figure.

DETAILED DESCRIPTION

For the purpose of this description, the term selectively magnetizable magnetic or ferromagnetic material means a material which is of a non-permanent magnetic type and which upon being subjected to a magentic field, will act as a magnet in that magnetic forces of opposite polarity are induced at opposite ends of the material, with these magnetic forces subsequently being removed upon removal of the magnetic field.

FIG. 1 shows a normally closed sealed contact 11 in accordance with the invention, in which first and second elongated elements in the form of reeds or contact members 12 and 13 are mounted in opposite end sections of an elongated sealed glass envelope 14. Cylindrical wire portions of the reeds 12 and 13 project from the envelope 14 and inner flattened portions of the reeds are disposed within the envelope with inner contact portions 12a and 13a engaged in slightly overlapped relationship, such as on the order of 0.030 inches. The first reed 12 is formed of a resilient electrically conducting ferromagentic material, such as a suitable iron-nickel alloy. The second reed 13, however, is of an electrically conducting, nonmagnetic material, and may or may not be resilient, as desired. The second reed 13 is of a nonmagnetic material having relatively high electrical conductivity, such as copper or aluminum, or suitable alloys of these metals, to reduce the electrical resistance which the sealed contact 11 presents in a circuit, although other nonmagnetic materials of lesser electrical conductivity, such as tungsten or brass, may be utilized if so desired. The inner contact portions 12a and 13a preferably are provided with gold-silver alloy contact surfaces (not shown) and the interior of the glass envelope 14 is filled with a suitable atmosphere, such as a forming gas of 97 percent nitrogen and 3 percent hydrogen, at slightly more than atmospheric pressure, in a manner well known to those skilled in the art.

In the embodiment of the invention shown in FIG. 1, an elongated magnetic member or element 16 in the form of a strip of a suitable selectively magnetizable ferromagnetic material, such as the iron-nickel alloy used for the ferromagnetic reed 12, is mounted outside of the glass envelope 14 in parallel relationship with respect to the nonmagnetic reed 13. An inner end portion 16a of the strip 16 also extends in opposed overlying relationship to the inner contact portion 12a of the ferromagnetic reed 12, and a coil 17, which is only partially shown, surrounds the resultant sealed contact 11. Preferably, the ferromagnetic strip 16 has an arcuate configuration which conforms to the outer surface of the glass envelope 14 and is secured thereto by a suitable adhesive, such as an epoxy resin available under the trade name "Epi-Rez" (Number 510), from the Celanese Resins Division, Celanese Corporation, Louisville, Kentucky, mixed with a suitable hardener.

Upon passage of a current through the coil 17 in a direction indicated by the arrows in FIG. 1, the current generates an electromagnetic field which produces magnetic polarities in the ferromagnetic reed 12 and the ferromagnetic strip 16, as shown. Since the magnetic polarities in the inner contact portion 12a of the ferromagnetic reed 12 and the adjacent inner end portion 16a of the ferromagnetic strip 16 are of opposite sign, the inner contact portion of the ferromagnetic reed is attracted toward the ferromagnetic strip and away from the nonmagnetic reed 13 to break electrical contact therewith.

FIG. 2 shows a normally closed sealed contact 11', which is substantially the same as the sealed contact 11 of FIG. 1, except that a ferromagnetic strip 16' is mounted on the outer surface of a glass envelope 14' below and in underlying parallel relationship to a ferromagnetic reed 12', as viewed in FIG. 2. In this embodiment of the invention, a coil 17' surrounds the sealed contact 11' and when electrical current is passed through the coil, as illustrated in FIG. 2, magnetic polarities of like sign are produced in the ferromagnetic reed 12' and the ferromagnetic strip 16', as shown. Thus, the ferromagnetic reed 12' and ferromagnetic strip 16' tend to repel each other and an inner contact portion 12a' of the ferromagnetic reed moves away from the ferromagnetic strip, and thus, away from an inner contact portion 13a' of a nonmagnetic reed 13', to break electrical contact therewith.

FIGS. 3 and 4 show the invention applied to normally open sealed contacts 11" and 11'", respectively. In this regard, the sealed contact 11" of FIG. 3 is similar to the sealed contact 11 of FIG. 1 except that ferromagnetic and nonmagnetic reeds 12" and 13" are mounted in a glass envelope 14" so that inner contact portions 12a" and 13a" of the reeds are in normally spaced relationship, and so that the inner contact portion of the ferromagnetic reed is on the side of the nonmagnetic reed opposite from a ferromagnetic strip 16" mounted on the outer surface of the glass envelope 14". Thus, upon energization of a coil 17" by the passage of current therethrough, as shown by the arrows, magnetic polarities of opposite sign are established in an inner end portion 16a" of the ferromagnetic strip 16" and the inner contact portion 12a" of the ferromagnetic reed so that the inner contact portion is attracted by the ferromagnetic strip and moves into engagement with the inner contact portion 13a" of the non-magnetic reed 13".

Similarly, the sealed contact 11'" of FIG. 4 differs from the sealed contact 11' of FIG. 2 only in that ferromagnetic and nonmagnetic reeds 12'" and 13'" are mounted in a glass envelope 14'" so that inner contact portions 12a'" and 13a'" of the reeds are in normally spaced relationship, and so that the inner contact portion 12a'" of the ferromagnetic reed is closest to a ferromagnetic strip 16'" mounted on the outer surface of the glass envelope. In this embodiment of the invention, when a coil 17'" is energized by passing current therethrough in a direction, as shown, magnetic polarities of like sign are established in the ferromagnetic reed 12'" and the ferromagnetic strip 16'" so that they repel one another, causing the inner contact portion 12a'" of the ferromagnetic reed to move into engagement with the inner contact portion 13a'" of the reed 13'".

FIGS. 5 and 6 illustrate a relay assembly 18 mounted on a printed circuit board 19 and incorporating the normally closed sealed contact 11 of FIG. 1. The relay assembly 18 includes a hollow support member or spool 21 of a suitable molded plastic, which has a central aperture 21a in which the sealed contact 11 is received, and which has an electrical coil 22 wound thereon. The opposite ends of the central aperture 21a in the spool 21 are filled with a suitable nonmagnetic encapsulating material 23, which securely anchors the sealed contact 11 in a desired fixed position in the spool 21. The encapsulating material 23 also anchors the cylindrical projecting portions of the reeds 12 and 13 against torsional movement in the glass envelope 14 so that electrical leads 24 can be wire wrapped directly onto the projecting portions of the reeds 12 and 13. The leads 24 then are wired at their other ends directly to suitable terminals, such as terminal posts 26 projecting from one end of the printed circuit board 19, or directly to other associated terminals (not shown), as desired. By way of illustration, the encapsulating material 23 may be the same above-mentioned epoxy resin available under the trade name "Epi-Res" (Number 510) from the Celanese Resins Division, Celanese Corporation, Louisville, Kentucky, mixed with a suitable hardener.

While the relay assembly 18 is capable of performing a "break" switching function, it is apparent that by utilizing one of the normally open sealed contacts 11" or 11'" of FIGS. 3 and 4, instead of the sealed contact 11, the relay could be used to perform a "make" switching function. Similarly, by utilizing one of the nrormally closed sealed contacts 11 or 11' of FIGS. 1 and 2, and one of the normally open sealed contacts 11" or 11'" of FIGS. 3 and 4, in combination with each other, or by utilizing one of the normally closed sealed contacts in combination with a conventional-type sealed contact, the relay 18 could be used to perform a "break-make" switching function.

In order to assist assembly and attain proper orientation, a well known slot and key arrangement is used wherein a longitudinally extending slot 21b is formed in the spool 21a, for receiving the magnetic strip 16, which acts as a key. The slot 21a may extend the entire length of the spool 21, as shown in FIG. 5, so so that the spool can universally accommodate the sealed contacts 11, 11', 11" and 11'" of FIGS. 1, 2, 3 and 4, respectively, or may extend only partially through the spool so that an inner end of the slot can be engaged by an adjacent end of the ferromagnetic strip 16, 16', 16" or 16'" to function as a longitudinal stop for the sealed contact being mounted in the spool, as desired.

The spool 21 of the relay assembly 18 also has a pair of downwardly projecting termianls 27 rigidly embedded in end walls 21c of the spool and to which wire ends 22a of the coil 22 are electrically connected by wrapping and soldering in a conventional manner. The end walls 21c of the spool 21 include integrally molded depending legs 21d which bear against the printed circuit board 19 at their lower ends, and the lower ends of the terminals 27 project through suitable apertures in the printed circuit board and are crimped to the underside of the board in engagement with circuit land areas 28. The crimped portions of the terminals 27 and the land areas 28 are encapsulated in solder 29 in a well known manner. Thus, the terminals 27 perform the dual function of connecting the coil 22 to the circuitry on the printed circuit board 19 electrically, and connecting the spool 21 to the board mechanically.

Summarizing, a new and improved sealed contact relay assembly 18 has been provided which is relatively simple in construction and relatively easy to manufacture. In this reagard, by merely adjusting the relative positions of the reeds of a sealed contact during the manufacture thereof, so that the reeds are either engaged or suitably spaced apart, and subsequently locating an external magnetic strip in one of four positions on the glass envelope of the sealed contact, as illustrated in FIGS. 1, 2, 3 and 4, a sealed contact of a desired construction and capable of a desired form of operation, readily can be produced. By utilizing one of the normally closed sealed contacts 11 or 11' in the relay 18, a normally closed relay condition also can be achieved without the use of a permanent magnet and the associated magnetic saturation and degaussing of the magnet required in certain prior known relay assemblies. Further, since one of the reeds 13, 13', 13" or 13'" of each sealed contact 11, 11', 11" or 11'" is nonmagnetic, the reed can be of a material having relatively high electrical conductivity, such as copper and aluminum, or alloys thereof, as compared to the electrical conductivity of most ferromagnetic materials. As a result, the electrical resistance which the relay 18 presents in a circuit is reduced, making it particularly adapted to electronic circuits which must operate at low power levels.