US2526685A - Polarized electromagnetic relay - Google Patents

Description

Oct. 24, 1950 o. l. PIRICE 2,526,535

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Patented Oct. 24, 1950 UNITED STATES PATENT OFFICE 2,526,685 'POLARiZEI) ELECTROMAGNETIC RELAY Osborne I. Price, Frederick, Md.; assignor, by mesne assignments, to Specialties, Inc., Syo'sset, N. Y., a corporation of New York Application October 10, 1946, Serial No. 702,431

8 Claims. 1

My invention relates broadly to electrical relays and more particularly to a novel construction of sensitive polarized relay.

One of the objects of my invention is to provide a construction of polarized relay having a balanced armature which is extremely rugged and capable of withstanding vibration and shock such as is encountered in aircraft, trains and other mobile equipment and yet having a high degree of sensitivity.

Another object of my invention is to provide an improved construction of sensitive polarized relay capable of inexpensive manufacture on a mass production scale and operative on currents as low as forty microwatts with less than one and one-half ampere turns at a speed exceeding twenty cycles per second.

Still another object of my invention is to provide a construction of polarized relay which is extremely compact in design with an armature suspended through a flexible strip operative to permit restricted angular displacement for effecting the opening and closing of contacts under.

control of extremely low operating currents.

A further object of my invention is to provide an improved mounting for the armature of an electromagnetic device with respect to a magnetic about two spaced points ofsupport and controlling the opening and closing of contacts.

Other and further objects of my invention reside in the construction of sensitive polarized relays as set forth more fully in the specification.

hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a top plan view of the polarized relay of my invention; Fig. 2 is an end View of the relay looking in the direction of arrow A in Fig. 1 showing the armature end of the polarized relay of my invention; Fig. 3 is a side view of the polarized relay shown in Fig. 1; Fig. 4 is an end view looking in the direction of arrow B in Fig. 1; Fig. 5 is a transverse sectional view through the relay taken substantially on line 55 of Fig. 2; Fig. 6 is a vertical sectional view through the relay taken substantially on line 6-6 of Fig. 5; Fig. 7 is a fragmentary transverse sectional view taken substantially on line 'l-l of Fig. 5; Fig. 8 is an enlarged sectional view showing the principles of 2 operation of the polarized relay of my invention; Fig. 9 is a schematic wiring diagram showing one of the circuit arrangements which may be employed for operating the balanced relay of my invention; Fig. i0 is an enlarged elevational view showing the suspension for the armature with respect to the electromagnet operating systemmatically; Fig. 11 is an enlarged cross sectional view taken substantially on line I I-i l of Fig. 10; Fig. 12 is an elevational view of the fastening means employed for establishing the points of flexure adjacent opposite ends of the suspension band which serves to mount the armature; Fig. 13 is a side elevational view of the fastening means illustrated in Fig. 12; Fig. 14 is a longitudinal sectional view taken substantially on line [4-44 of Fig. 12; Fig. 15 is a transverse sectional view taken substantially on line 15-45 of Fig. 12; Fig. i6 is a transverse sectional view taken substantially on line iiil6 of Fig. 12; and, Fig. 17

is a schematic sectional View on an enlarged scale taken substantially on line l1'-l'l'of Fig. lland showing the mariner in which the armature may flex about spaced points determined by the coaction of the fastening means with the suspension strip.

Referring to the drawings in detail, reference character I designates a base of insulation material upon which the polarized relay of my invention is mounted. A yoke-shaped block 2 of nonmagnetic material such as brass is mounted on base i and providesa s'upport for the electromagnetic operating system of the relay. Theelectromagne'tic operating system includes a pair of flat magnetic end plates 3 and-5 of good magnetic material fully annealed such as soft iron orpreferably 47% or 80% nickel iron alloy. End plate 3 is assembled with respect to the supporting block 2 by means of attachment screws 3a which enter block 2 in spaced positions for supporting the plate'3 in a plane substantially normal to insulated base I. Plate 5 is secured to block 2 at the opposite side thereof by means of screws 5a which enter the opposite side of b ock 2. I The magnetic plate 3 carries a pair of cores 6 and Ed made from good magnetic material such as soft iron, 47% Or 80% nickel iron alloy, depending upon the degree of sensitivity required; The lower the coercive force of this material, themore the sensitivity of the relay, other factors of construction being taken into consideration. The magnetic cores 6 and 6a project toward the central cutout portion 51; of magnetic plate 5 and carry the magnetic operating windings I5 and I6 thereon. The cores 6 and to project toward the opening 5?) in the plate and terminate in pole pieces 6 and 6a. The pole pieces 6' and 6a are each flattened on their ends terminating in a plane which is coincident with one side of the magnetic plate 5. The coil supports I50. and I60. for the windings l5 and I5 are each spaced from the plane of the magnetic plate 5 for a distance fixed by the thickness of the flange constituting each pole piece 6' and 8a for magnetic cores 6. The coil supports I50, and Ilia occupy substantially the area covered by the opening 5b in plate 5 as will be seen more clearly in Figs. 2 and 4.

Thus .a sturdy and rigid and magnetic frame is provided by the erection of the two magnetic plates 3 and 5 on opposite ends of the block 2 with the magnetic cores projecting toward the open area 5b within plate 5 with the windings l5 and I6 disposed on the magnetic cores and between the two magnetic plates 3 and 5. The magnetic plate 5 is larger in physical dimension than magnetic plate 3 and extends beyond the limits thereof at each end and at the top thereof. The magnetic plate 5 serves 'as a support for suspending the magnetic armature 4. The magnetic armature 4 is constructed from magnetic iron or preferably 47% or 80% nickel iron alloy. The armature 4 is formed in the shape of a cross having a relatively wide central portion and integrally formed relatively narrower tongues projecting on opposite sides thereof and disposed over the pole pieces 5' and 6a and rounded at their extremities indicated at 4a and 4b. The armature is suspended coplanar with the magnetic plate 5 by means of spring suspension strip 1 having end portions la and lb extending in opposite directions beneath the fastening plate 8 and terminating in eyelet portions lo and ld which are secured by screws I! and l8 on opposite sides of the frame constituted by magnetic plate 5. The spring suspension strip l and the adjacent end portions la and lb are attached to the armature 4 by means of screws l9 and 20, which pass through apertures 8a and 8b in fastening plate 8 and through aligned spacer members Mia and lSb and a and 20b arranged on opposite sides of spring suspension strip 1 and enter armature 4. Spacer members [9b and 20b are provided on screws l9 and 20 intermediate the suspension strip l and the armature 4 for facilitating the clamping of the end portions la and lb of suspension strip 7 to armature 4 while allowing the passage of longitudinally extending strip 46 in a direction normal thereto. The apertures in the end portions la and lb may be sufficiently enlarged for the passage of screws I9 and 20 or may be in the form of elongated slots extending lengthwise of strip 1 for permitting adjustment of the position of armature within the aperture 5b of plate 5 for precisely centering the armature for movement with respect to the plate 5. The armature 4 is centered within the opening 512 of plate 5 so accurately that a space of approximately .004" to .008" is provided between opposite edges of the armature and the inner edges of the opening 5b so that a good magnetic path is assured due to the small gap, although the gap is sufliciently large to insure the free rocking movement of the armature within the opening 5b without touching the interior edges of the opening 5b. The fact that armature 4 is cut out at diagonally opposite sides thereof in the four corners as shown reduces the inertia of movement of the armature.

Figs. 10-17 show on an enlarged scale the manner of fastening the suspension strip 1 to the armature 4. The fastening plate 8 has the tapered ends and 8d projecting therefrom and bent at an angle to the plane thereof so that the points 80 and 8d contact the resilient end portions la. and lb of suspension strip l in positions over the solid portions of plate 5 and adjacent the securing screws I1 and I8. These points of contact serve as centers about which the armature angularly flexes as illustrated more particularly in Fig. 17. The parts are magnified in size in Fig. 17 in order to show the theoretical displacement of the fastening means 8 with respect to suspension strip 1. The fastening strip 8 normally occupies the solid line position normal to the axis A. The angular displacement of the armature permits movement of the fastening means 8 to the positions 8' illustrated in dotted lines normal to axis B, or to the position 8 shown in a dot-dash line normal to axis C. Concurrently with this rocking movement the suspension strip 1 flexes about the point of contacts 8c and ad for controlling the movements of the armature which is attached to the fastening means 8.

The magnetic plate 5 is recessed adjacent opposite ends of the interior edges of the opening 5b in alignment with an axis through the magnetic cores 6 and 6a as represented at 50 and 5d. These cut portions permit the movement of the opposite ends 46a and 46b of the longitudinally extending strip 46 which is suitably connected or secured to the armature 4. 46b each support contacts 46a and 46b which serve to establish alternate connection with aligned adjustable contacts 2| and 22 carried by adjustable screws Zla and 22a. The adjustable screws 2la and 22 each have headed ends 220 and 22d, respectively, which may be engaged by a tool for accurately adjusting the contacts through extremely fine threaded connections with the standards 9 and 9. The standards 9 and 9 are formed of brass or non-magnetic material and are insulatingly secured by suitable screws or rivets 24 to the magnetic plate 5. The screws or rivets 24 pass through plate 25 and insulation members 26 and 21 and enter plate 28 for thereby clamping standard 9 to the magnetic plate 5. The insulation members 26 and 21 are flanged to engage opposite sides of magnetic plate 5 and form insulation means for preventing electrical contact between screws 24 and magnetic plate 5. Plate 25 serves as a terminal means in coaction with the headed ends of screws 24 for the adjustable contact carried by standard 9. As represented in Fig. 9, the terminal connection for adjustable contact 2| is made through conductor 29 to the standard 9. The connection for adjustable contact 22 is made through conductor 30 to the standard 9'.

An intermediate connection 3| is made through screw IT or l8 by which electrical connection is established through resilient suspension strip 1 to armature 4 by which the electrical circuit is completed through contacts 46a and 46b carried on the ends of strip 46.

The extent of the angular flexing of the armatur is controlled by small stops 32 and 33 carried by the strap 46 in alignment with the magnetic pole pieces 5 and 6a. These stops 32 and 33 serve as limiting means for preventing direct contact between the armature and the pole pieces 5 and Ba. or other non-ferrous material and constitute breakers to keep the armature 4 from freezing The ends 46a and They are formed from brass, copper- 5 against the pole pieces 5 or So should the. adjusting screws Zia and 22a be opened too far.

A permanent magnet member ID in the form of a block is housed beneath the yoke-shaped block '2 and clamped between the magnetic plates 3 and 5 for providing a return path through the magnet system. The armature 4 has approximately .010" between itself and the pole pieces 6' and 6a and when the armature is against one core, there will be approximately .020" space from the armature to the other core. The adjusting screws 21a and 22a adjust the armature 4 so that there appears a gap in one or the other contacts of from .002 to .010", depending on the sensitivity desired.

The magnet windings l5 and H; are protected by cellulose acetate, textile thread of insulating material such as artificial silk, or other suitable insulating material.

The permanent magnet path is indicated in Fig. 6 by the heavy dotted line 34. The electromagnetic path is indicated by the dash-dot line 35 in Fig. 8. I have found that considerable improvement in operating efliciency is obtained when plate 3 and armature 4 are constructed from material of high permeability, hydrogen annealed, in order that the relay may be made as sensitive as possible. In order to increase sensitivity, I find it desirable to form the suspension 1a-|'1b from very thin resilient ribbon-like material which, when flexed, tends to restore the armature 4 to neutral position. The permanent magnet I is made as large as possible so that a high degree of magnetization is maintained through the armature ready for the super-position of the electremagnet path produced by the alternate excitation of the magnetic windings l and 16. The permanent magnetic path indicated by the heavy dotted line 34 and the electromagnetic path indicated by the dash-dot line 35 are arranged in planes substantially normal to each other. That is to say, the lines of force established by the permanent magnetic field represented by heavy dotted line 34 are substantially at right angles to the lines of force established by the electromagnetic path indicated by the dash-dot line 35.

The operation of the relay as a polarized relay will be clear if we assume that the magnetization of each pole piece by the current in the magnetic winding is equal to the magnetization by the permanent magnet. Energization by one coil will then double the magnetic flux in one pole piece and energization by the other coil will neutralize the flux in the other coil. Thus current in one direction causes one end of the armature to be attracted to one pole piece while current in the other direction will cause the other end of the armature to be attracted to the other pole piece. While the foregoing explains the principle of operation it will be obvious that it is not necessary that the magnetization due to the electromagnetic coils shall be of equal intensity to the magnetization provided by the permanent magnet.

As illustrated in Fig. 9, the exciting windings l5 and I6 may be divided into a multiplicity of separate windings which I have represented at 36, 31, 38 and 39. Separate circuits may lead to these independent windings, that is to say, circuit 40 may be utilized to excite winding 36; circuit 4| may be utilized to excite winding 31; circuit 42 may control winding 38; while circuit 43 controls winding 39. Depending upon the integral magnetic field produced by the windings, armature 4 may be flexed to one angular position or the other for controlling the opening or closing of electrical circuits through the different sets of contacts adjacent opposite ends of the relay armature.

The relay of my invention has been found particularly effective for polarized operation in which negative pulses are supplied to one winding and positive pulses are supplied to the opposite winding, thereby effecting rapid flexing of the suspended relay armature from one angular position to the other and controlling separate electrical circuits.

In assembling the relay of my invention I mount the magnetic cores 6 and 6a on plate 3 and then secure plates 3 and 5 on opposite sides of the block 2. Permanent magnet I0 is then inserted beneath the yoke-shaped block 2 and clamped between magnetic plates 3 and 5. Block 2 is then secured by means of screws 44 and 45 to the insulated base I. The posts 9 and 9' are mounted in insulated relation to the magnetic plate 5. Armature 4 is then suspended in the open recess 5b in plate 5 by means of the flexing strips 1a1-1b supported at H and I8 on magnetic plate 5. The structure of the relay of my invention is particularly adapted for miniature relays. The size of the base I, for example, in the form of my invention, which has been found very effective, is but 1% x 1 The maximum height of the relay above the base i is but 1% which is the width of the magnetic plate 5. Thus it will be seen that the relay is built within extremely small physical dimensions. The drawings have been made on an enlarged scale in order to clearly bring out the details.

While I have described my invention in one of its preferred embodiments which has been found to be very practical in manufacture, production, and operation, I desire that it be understood that modifications may be made and that I do not intend any limitations upon the structure of my invention other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In an electrical relay a permanent magnet, a pair of parallel magnetic plates positioned at opposite ends of said permanent magnet, one of said plates including a central aperture, magnetic pole pieces parallel to said magnet secured to the other of said plates and projecting toward the apertured plate and energized by the permanent magnet with similar polarity, electro magnetic operating windings associated with said pole pieces for alternatively exciting the pole pieces in opposition to the permanent magnetic flux of said pole pieces, a magnetic armature mounted within the apertured magnetic plate and sus pended for rocking movement under control of the excitation of said pole pieces alternatively by said windings.

2. An electrical relay comprising a pair of parallel plates of magnetic material, a permanent magnet extending between said plates, a pair of pole pieces carried by one of said plates and extending between said plates, a rockable armature mounted in magnetic relation to the pole pieces and carried by the other plate, said last mentioned plate having the form of a closed frame said pole pieces being energized with similar polarity by the permanent magnet and windings on said pole pieces energizable to reverse the polarity of the pole pieces alternatively to rock the armature a flexible strip extending transversely of said closed frame intermediate said pole ieces connected thereto, a clamp fastening said armature to said strip, said clamp teriminating in points establishing contact with said flexible strip adjacent the connections of said :strip with said closed frame for forming centers about which said strip flexes for controlling the movement of said armature.

3. In an electrical relay, a permanent magnet, a pair of plates of magnetic material secured to oppose ends of said magnet, a pair of substantially parallel pole pieces extending between said plates substantially parallel to said magnet and secured to one plate, said pole pieces being energized by said permanent magnet with similar polarity, the second plate having a central aperture adjacent the ends of said pole pieces, an armature of magnetic material rockable in said aperture adjacent said pole pieces alternatively toward one or the other of said pole pieces, and electromagnetic operating windings associated with said pole pieces energizable to apply magnetic energy of opposite polarities to said pole pieces whereby the magnetic polarity of one pole piece due to the permanent magnet is opposed and that of the other is increased to rock said armature, said rockable armature being positioned closely adjacent the apertured plate to provide a substantially closed magnetic path through the permanent magnet, the magnetic plates, the pole pieces and the rockable armature.

4. An electrical relay comprising a magnetic frame structure carrying an electromagnetic operating system, an armature operative by said system and means for suspending said armature in coacting relation to said electromagnetic operating system, comprising a flexible strip secured at opposite ends to said frame structure, and clamping means for fastening said strip to said armature including a rigid member tapered at opposite ends and establishing point contact abutting said flexible strip adjacent said frame structure.

5. An electrical relay comprising a magnetic frame structur carrying an electromagnetic operating system, an armature operative by said system and means for suspending said armature in coacting relation to said electromagnetic operating system, comprising a flexible strip secured at opposite ends to said frame structure, and

clamping means for fastening said strip to said armature including a rigid member tapered at opposite ends and directed toward and establishing point contact with said flexible strip immediately over said frame structur for forming points of fiexure about which said armature is angularly rocked under control of said electromagnetic operating system.

6. An electrical relay comprising a magnetic frame structure carrying an electromagnetic operating system, an armature operative by said system and means for suspending said armature in coacting relation to said electromagnetic operating system, comprising a flexibl strip secured at opposite ends to said frame structure, and clamping means for fastening said strip to said armature including a rigid member tapered at opposite ends and angularly directed toward and establishing point contact with said flexible strip directly opposite the support formed by said frame structure and immediately adjacent the secured positions of said strip for forming points about which said armature is angularly shifted under control of said electromagnetic operating system.

7. An electrical relay comprising a magnetic frame structure carrying an electromagnetic operating system, an armature operative by said system, a transverse flexible strip extending substantially normal to the longitudinal axis of said armature and connected at opposite ends with said frame structure, and means fastening said armature to said transverse strip comprising a rigid plate tapered at opposite ends and directed into point contact with said strip adjacent said frame structure as a support and establishing points of flexure for said armature on said transverse strip under control of said electromagnetic operating system.

8. An electrical relay comprising parallel plates of magnetic material, a permanent magnet extending between said plates in magnetic relation thereto, a pair of pole pieces parallel to said magnet extending between said plates, one plate having an opening opposite the ends of the pole pieces, a rockable armature in said opening with its ends extending over the pole pieces and its sides closely adjacent the sides of the opening in the plate, magnetic operating windings of opposite polarities on said pole pieces arranged to be energized to rock the armature, the construction and arrangement being such that a substantially closed magnetic circuit is provided including the permanent magnet, the pole pieces, the end plates and the armature, and the magnetic operating windings when energized serving to increase the magnetic flux through one pole piece and the adjacent end of the armature while decreasing the magnetic flux through the other pole piece and the armature to attract one end or the other of the armature alternatively.

OSBORNE I. PRICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 210,886 Watson Dec. 17, 1878 1,177,988 Buhl Apr. 4, 1916 1,606,164 Garvin Nov. 9, 1926 1,646,234 Creed Oct. 18, 1927 2,251,001 Quam July 29, 1941 2,269,108 Hubbell et a1. Jan. 6, 1942 2,404,227 Hall July 16, 1946 FOREIGN PATENTS Number Country Date 125,898 Australia Dec. 10, 1931

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