US2933572A - Relay - Google Patents

Description

April 19, 1960 HOWELL ETAL 2,933,572

RELAY Filed Nov. '7, 1958 ,6! dIAIg ENTORf We? wag? United States Patent RELAY Hugh A. Howell, Berwyn, and Jerry L. Jedd, Arlington lleilglhts, Ill., assignors to Oak Mfg. Co., a corporation of inois Application November 7, 1958, Serial No. 772,446 1 Claim. (Cl. 200-87) This invention relates to a relay and more particularly to a flexible relay construction wherein a contact operating portion may be hermetically sealed while the energizing winding is readily available for replacement or change.

As is well known, a relay is an electric switch which may be electrically actuated for operating the same. In its simplest form, a relay comprises an energizing winding with a ferromagnetic circuit including a movable armature. Associated with the armature are means for opening or closing electrical contacts. Such devices are used where the amount of power to be controlled by the relay is far greater than can be handled by the switch controlling the energizing winding circuit. Thus in many instances a switch for handling minute amounts of power must be able to turn on or off quickly larger amounts of power than the switch itself could handle.

Relays for accomplishing the above are generally old and have been made in all kinds of sizes, shapes and power ratings. For many applications it is desirable to have the relay hermetically sealed insofar as the relay contacts themselves are concerned. Such relay contacts may operate under relatively high temperatures where the absence of a hermetic seal creates problems in corrosion. Apart from any possible high temperatures within which the relay may operate, arcing at the relay contacts generally results in pitting or burning of the contacts particularly if the contacts are exposed to atmosphere. In addition, relays are sometimes required to remain on standby for long periods of time without operating but at all times to be ready to operate if the need should arise. In such case, relay contacts when exposed to atmosphere will corrode and'render the relay inoperative.

It also happens that a relay may control a low power low voltage circuit of such delicacy as to make it necessary to avoid spurious relay potentials. Such spurious potentials may result from thermoelectric effects occurring at the junction of dissimilar metals or may occur because of breakdown of insulation having an organic base.

This invention provides a contact relay construction which meets the above problems to a remarkable de- For a full understanding of the invention, reference will now be made to the drawings wherein- Figure 1 is a top view of the new relay with the cover removed.

Figure 2 is a section along broken line 2-2 of Figure 1 with the top cover in position.

The relay comprises annular base of suitable ferromagnetic material such as soft iron. Pressed against base 10 is cup-shaped housing 12 of ferromagnetic material such as soft iron.

Disposed within housing 12 is energizing winding 15 having leads 16 and 17 passing out through suitable apertures in end wall 18 of the housing. Winding 15 is preferably disposed on a suitable bobbin in a manner well 'known in the art.

Disposed axially of and passing through winding 15 is ferromagnetic core 20 having threaded end portion 21 passing through a suitable aperture in end wall 18 of the housing. Nut 22 cooperates with threaded end 21 at the core to lock the housing in position against base 10.

Core 20 has end portion 24 which extends beyond winding 15 and is sealed in nonmagnetic centering ring 25. Ring 25 may be of metal or glass. In its simplest form ring 25 may be of brass and may be soldered or brazed to end portion 24 of core 20. Core 20 has pole face 26 at end portion 24, the pole face being preferably flush with the top surface of ring 25. Ring 25. is hermetically sealed to the inside face of annular base 10.

Anchored in base 10 is rivet 30 to which is attached spring reed 31 carrying armature 32. Rivet 30 may be of any material. Armature 32 extends across part of base 10 and ring 25 over pole face 26. Armature 32 is normally biased away from pole face 26 but can bridge the space between ferromagnetic parts 24 and 10.

Rigidly supported on the free end portion of armature 32 is a small glass seal comprising an outer metal ring 33 and an inner movable contact arm 34 separated by glass annulus 35. Movable contact arm 34 is connected by flexible wire 37 to terminal 38. Terminal 38 is set in a glass seal.

Movable contact 34 carries movable contact point 39 extending beyond the armature. Contact point 39 cooperates with one or more stationary contacts 40 carried by metal arms 41 supported in glass seals 42 and 43.

The entire assembly of relay contacts and armature is covered by cap 44 which has a flanged rim for engaging the edge of base 10. Cap 44 may be sealed to base 10. Since the various parts supported by base 10 on the cap side are hermetically sealed to the base, it is clear that the entire region containing the relay contacts will be sealed. This region may be filled with an inert gas like nitrogen or a reducing atmosphere like hydrogen or may be evacuated. The various leads to the relay contacts are available on the lower side of base 16, this side being termed the atmospheric side. Removable cap 50 for the winding and housing 12 may be provided to protect the housing and coil against damage. This removable cap, however, need not provide a hermetic seal.

It is clear that the relay may be provided with as many contacts as desired. Inasmuch as armature 32 is carried by separate spring 31, it is possible to make the armature of very soft iron having minimum remanence. By having spring 31 of nonmagnetic material such as Phosphor bronze or beryllium copper, long relay life and reliable armature operation may be assured. The armature itself bridges the nonmagnetic gap between magnetic base plate 10 and core portion 24 so that an excellent magnetic circuit is established.

Annular members 10 and 25 as well as end portion 24 of the core together form a composite base member having at least one face, in this instance the outer face, flat to provide a base surface.

While the current leads for the relay contacts pass through the ferromagnetic portion of the composite base, it is possible to have such leads go through the nonmagnetic portion of the composite base and provide clearance openings in armature 32.

What is claimed is:

A relay comprising an annular ferromagnetic member having two flat faces, a nonmagnetic annular member disposed within said ferromagnetic annulus, a ferromagnetic core having one end portion filling the region within said second annulus, said one end portion of said core and said two annular members being flush at one side to provide one sealed continuous flat face on a. composite base member, an armature disc having a diameter some- Patented Apr. 19, 1960 what larger than'the inside diameter of said ferromagnetic member, said armature being adapted to be disposed aaginst said one face to provide a ferromagnetic bridge across the nonmagnetic annulus, a spring reed having one end supported on said ferromagnetic member and carrying the armature at the other end, said spring reed being disposed on the one face side of said composite member and normally biasing said armature away from said one face, a glass seal comprising a central conductor surrounded by a glass ring in turn surrounded by an outer metal ring, means for rigidly attaching said outer metal ring of said glass seal to the armature, a movable contact supported on said central conductor of said glass seal, a flexible wire lead attached to said central conductor, at least one stationary contact cooperating with said movable contact, a giass seal construction for said flexible lead and for said stationary contact, each of said glass seal constructions being disposed in apertures in said ferromagnetic member with the central con,- ductor in each case passing through said ferrornaguetic member to the other face of said composite base member so that current leads for said contacts extend from the one faceside of said composite base member through said composite base member to be available for use at the other face of said composite base member, a cap attached to said ferromagnetic member to cooperate with the one face of said composite base member to provide a sealed chamber for said contacts and armature, an energizing winding around said core where it extends beyond the other face of said base member, and a housing of ferromagnetic material around said winding and providing a ferromagnetic coupling between the other end of said core member and the other face of said ferromagnetic member.

References Cited in the file of this patent UNITED STATES PATENTS 27,539,547 MDSsmfin a at an... J n. 30., 19.51 2,834,847 Jennings r n-ant"- Mas 13, 1958

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