US 3668576 A
Electrical relays of the type having an armature positioned for selective contact between contact faces of pole pieces within a glass envelope under the influence of electrical flux, with or without biasing permanent magnets. Low reluctance material is connected to the exterior armature stem and extends around opposite sides of the relay and has spaced ends, each of which is magnetically coupled to one of the pole pieces of the relay. Operating coils are positioned around the low reluctance material on opposite sides of the relay envelope and are within the side projection outline of the envelope.
Description (OCR text may contain errors)
United States Patent Krizman et al.
 FLAT PACK RELAY WITH PLURAL OPERATING COILS  Inventors: Theodore M. Krizman, Osceola; Clayton M. Emmons, Elkhart, both of Ind.
 Assignee: The Adams & Westlake Company Notice: The portion of the term of this patent subsequent to Oct. 6, 1987, has been disclaimed.
 Filed: Nov. 5, 1970  Appl.No.: 87,165
52 us. Cl .335/153  Int. Cl ...Hlh51/24,H01h5l/28  Field of Search ..335/ll-154  References Cited UNlTED STATES PATENTS 3,005,072 /1961 Brown ..335/l52 *June 6, 1972 3,227,839 l/1966 Brown ..335/l53X 3,533,025 10/1970 Krizman ..335/l51 Primary Examinerl-larold Broome Assistant ExaminerR. N. Envall, Jr. Attorney-Mann, Brown, McWilliams & Bradway  ABSTRACT Electrical relays of the type having an armature positioned for selective contact between contact faces of pole pieces within a glass envelope under the influence of electrical flux. with or without biasing permanent magnets, Low reluctance material is connected to the exterior armature stem and extends around opposite sides of the relay and has spaced ends, each of which is magnetically coupled to one of the pole pieces of the relay. Operating coils are positioned around the low reluctance material on opposite sides of the relay envelope and are within the side projection outline of the envelope.
5 Claims, 3 Drawin g lji gl ire s v PATENTEDJUH 6 I972 INVENTO RS THEODORE M. KRIZMAN CLAYTON M. EMMONS BY WM ZW VlFMM ATTO RN EYS FLAT PACK RELAY WITH PLURAL OPERATING COILS The present invention is directed to new and useful improvements in relays of the type wherein a swingable armature makes selective contact with a pair of contact faces of pole pieces within a glass envelope under the influence of electrical flux and/or permanent magnet flux, and is particularly concerned with improvements in magnetic circuitry and arrangements which reduce the projection dimension of relays.
Stauder U.S. Pat. No. 3,497,840, issued Feb. 24, 1970, and assigned to the assignee of the present application, discloses the use of low reluctance material extending between the pole pieces of a relay and around the opposite sides of the envelope of the relay and into magnetic contact with the exposed armature stem. The low reluctance material extends around the customary electrical operating coil for the relay. The magnetic circuitry thus presented, as fully disclosed in the aforesaid Stauder patent, reduces air gaps in the magnetic circuitry, and has attendant advantages such as a reduction in copper required in the coils and smaller size of relays. The arrangement disclosed in the Stauder patent requires extension of the low reluctance material through the glass envelope of the switch which introduces some difirculties of fabrication. In our copending application, Ser. No. 795,497, filed Jan. 31, 1969, now U.S. Pat. No. 3,533,025, issued Oct. 6, 1970, we disclose relays utilizing low reluctance material extending around one side only of theenvelope of relays of the type herein referred to and with an operating coil positioned laterally to one side of the glass envelope and within the projection outline of the envelope of the switch. The low reluctance material is magnetically coupled to the exposed armature stem, extends through the operating coil, and into the space between the pole pieces of the relay. Relays of this type, as fully disclosed in the said application, reduce manufacturing costs, weight, power consumption and magnetic interaction with adjacent electrical components in an electrical installation.
Arrangements as disclosed in said application can be closely mounted on printed circuit boards. In' both the aforesaid Stauder patent and in our copending application the low reluctance material extends between the pole pieces of the relay. This requires certain accuracies in fabrication techniques in order to produce the exact magnetic characteristics desired in a relay.
The present invention has for its major purposes to utilize low reluctance material to reduce air gaps in relays as in the aforesaid patent and in the aforesaid application, while permitting economies in fabrication techniques and providing a construction such that magnetic shielding of relays may be reduced or eliminated because of reduced magnetic interaction of relays in close proximity to one another. I
These and other purposes will become more apparent from time to time in the course of the ensuing specification and claims, when taken with the accompanying drawings, in which:
FIG. 1 is a front elevational view of a typical relay embodying the principles of the present invention;
FIG. 2 is a side view of the relay illustrated in FIG. 1; and
FIG. 3 is an enlarged, partial sectional view of the pole piece and armature contact portions of the relay illustrated in FIGS. 1 and 2.
Like elements are designated by like characters throughout the specification and drawings.
With particular reference now to the drawings, and in the first instance to FIGS. 1-3, the numeral generally illustrates a switch of the type incorporating a glass or glass-like envelope 11 with an armature stem 12 projecting from one end of the envelope. The swingable armature 13 of theswitch is positioned within the envelope for selective movement into operating contact with one or the other of contact faces 14 and 15 of pole pieces 16 and 17 which extend through the other end of the envelope and to the exterior. Preferably, the armature contacts the contact faces 14 or 15 without contacting the remainder of the pole piece associated therewith. A ceramic spacer 18 may be positioned between the pole pieces 16 and 17 at the inner wall of the envelope as illustrated. The pole pieces and armature may be formed from a magnetic material such as a nickel-iron alloy. A body of mercury may be introduced into the envelope during the manufacturing process, and, through capillary action, the armature and the contacts of the pole pieces are kept wetted with mercury. The armature and portions of the pole pieces within the envelope may have special configurations to enhance the performance, reliability and operating sensitivity of the relay. The envelope may be gas filled, if desired. Switches as thus described are known to the art and are discussed in a number of patents and publications, including U.S. Pat. No. 2,609,464 and U.S. Pat. No. 3,054,873, which disclosures are hereby incorporated by reference.
In accordance with the present invention a permanent magnet 19 is positioned between the exposed ends of the pole pieces 16 and 17 and bonded to one pole piece, with insulation 19a between the other pole piece and magnet. The permanent magnet has the magnetic poles thereof oriented so as to impart opposite polarities to the contact faces 14 and 15 of the pole pieces 16 and 17, respectively. For example, as illustrated, the pole piece 16 may have a north polarity while the pole piece 17 may have a south polarity.
In lieu of positioning magnet 19 between the exposed ends of the pole pieces, the magnet may be positioned alongside of the pole pieces so as to impart opposite magnetic polarities to the two pole pieces as disclosed in Emmons U.S. application,
Ser. No. 737,750, filed June 17, 1968 now U.S. Pat. No. 3,559,122,issued Jan. 26, 1971.
In further accordance with the invention, strips or wires of low reluctance material 20 and 21 extend along opposite sides of the envelope and through electrical operating coils 22 and 23. The strips are fixed to and magnetically coupled to the exposed armature stem as at 24. The strips are also magnetically coupled to the pole pieces 16 and 17. For example, strip 20 on one side of the envelope may be magnetically coupled to pole piece 16 by bonding the end 25 of that strip to electrical insulation 26 which is in turn bonded to the pole piece 16. The other strip 21 has an end magnetically coupled to the pole piece 17 as by bonding its end 27 to electrical insulau'on 28 which is in turn bonded to pole piece 17 In lieu of using electrical insulation between the pole pieces and the ends 25 and 27, electrical insulation may be placed between stem 12 and the lower ends of the strips at 24 while the ends 25 and 27 are fixed together to the pole pieces. In either construction the pole pieces are not electrically connected to the armature stem through the strips. The ends 25 and 27 are preferably located at positions more closely to the envelope than permanent magnet 19. The strips 20 and 21 each has a generally U-shaped form, when considered as extending from the associated pole pieces to the armature stem. As a matter of convenience, the two strips 20 and 21 may be formed from a single strip bent into the configuration illustrated with the lower medial portion fixed to and magnetically coupled to the armature stem.
The electrical operating coils 22 and 23 are connected in series so that electrical flux induced in the strips 20 and 21 produces one polarity, as, for example, a north polarity on the pole pieces, while introducing opposite polarity as, for example, a south polarity, as indicated in the drawings, on the armature. The polarity induced may be reversed by changing the polarity of the connections to the coils. It should be understood that the operating coils 22 and 23 may be connected in parallel, provided the wiring arrangement is such as to produce one polarity on the armature and the opposite polarity on the pole pieces when the coils are energized. A series connection is preferred so that if one coil is inoperable, the entire relay is inoperable.
It should be noted that the operating coils 22 and 23 each has a smaller diameter than that of the glass envelope 1 l and is within the projection outline of the envelope when viewed from the side as illustrated in FIG. 2. The coil diameter may be approximately equal to the envelope diameter but it is preferably smaller. Therefore, when relays of the type disclosed herein are positioned on printed circuit boards so that a plan view of the circuit board presents a relay of the type illustrated in FIG. 1, the amount of volume presented by the relay in terms of projecting from the circuit board is that illustrated in FIG. 2.
It should be understood that relays of the type disclosed herein may have particular operating characteristics, such as bistable or single side stable operating characteristics through selection of permanent magnet arrangements and magnetic biasing as known to the art. The use of therods or strips of low reluctance material, as described herein, provides a much more efficient magnetic circuit. It may also reduce any magnetic interaction with adjacent, electrical components in an assembly. The strip of low reluctance material may be formed from known electrical grades of steel, certain grades of permalloy, vanadium permendur, soft annealed iron, or a nickeliron alloy.
The particular arrangement disclosed herein reduces the size of operating coils. Each coil may be considerably smaller than the single operating coil disclosed in the aforesaid Stauder patent and in our aforementioned copending application. When relays as disclosed herein are used in an arrangement with other electrical components, the coils are closer to other electrical components than other parts of the relay. The reduction in coil size, therefore, reduces magnetic interaction with adjacent electrical components. The use of the dual coil structure makes it relatively easy to use low reluctance strips and provide the same electrical bias on the pole pieces of the relay.
Relays as disclosed herein may be manufactured for single side stable or bistable operation through selective orientation and strength of the magnetism provided by the permanent magnet 19 in accordance with practices known to the art.
One of the advantages of the relay constructions that have been described resides in their utility in computer equipment and high speed switching equipment. In equipment of this type various units of the relay gear are mounted on board modules and there may be as many as a hundred of such board modules mounted in parallel arrangement and having minimal spacing between them so as to conserve overall space. l-leretofore the smallest commercial subminiature relay (with an envelope diameter of approximately 0.22 inch) has had a projection dimension of 0.4 inch which has made it necessary to use boards mounted on inch centers to avoid shorting between the modules. The relays of this invention, as formed with switch envelopes of approximately 0.22 inch diameter, by reason of the magnetic circuit that is used, can have as little as 0.3 to 0.325 inch of overall projection dimension which makes it possible to use boards mounted on k inch centers when using boards of approximately one-sixteenth of an inch thick. For this spacing it is usually desirable to have the relays encapsulated in suitable insulating material to minimize short-circuiting between adjacent boards.
1. A relay of the type having an armature and pole pieces positioned within a glass-like envelope with the pole pieces and armature stem extended outwardly beyond the confines of the envelope at opposite ends thereof and in which electrical flux is utilized to bias the armature into contact with at least one of the pole pieces to selectively make and break contact with the pole piece contacts of the relay within the envelope, the improvement comprising elongated wire-like magnetic core material extending along both opposite sides of the exterior of the envelope and having opposite end portions, one end portion of said material on each side of said envelope being closely adjacent to and in magnetic contact with the portion of the armature stem outside of the envelope and the other end portion of said material on each opposite side of said envelope being extended to a position closely adjacent one pole piece, and operating electrical coils surrounding said material and positioned on opposite sides of said envelope whereby electrical flux induced in said strips imparts one polarity to the pole pieces and an opposite p0 anty to said armature.
2. The structure of claim 1 in which said operating coils and material have dimensions such that they are within the outline dimensions of the envelope when the envelope is viewed from the side having said material.
3. The structure of claim 1 characterized by and including permanent magnet material associated with the pole pieces so as to provide selected permanent magnetic polarities for the pole pieces.
4. The structure of claim 1 wherein the magnetic core material has electrical insulation to prevent completion of an electrical circuit through the core material and to the armature stem and pole pieces.
5. A relay of the type having an armature and pole pieces positioned within a glass-like envelope with the pole pieces and armature stem extended outwardly beyond the confines of the envelope and in which electrical flux is utilized to bias the armature into selective contact with one or the other of the contact faces of the pole pieces within the envelope, the improvement comprising electrical operating coils positioned on opposite sides of the envelope and within the side projection outline of the envelope, low reluctance material extending through ends of said coils and magnetically coupled to the exposed arrnature stem, said low reluctance material having portions extended from the other ends of said coils and in closely spaced and magnetically coupled relation to said pole pieces, the electrical connections of the coil and the magnetic arrangement being such that the electrical coils impose one polarity on the armature, when said coils are energized, and the opposite polarity on said pole pieces.
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