US2411563A - Electromagnetic relay - Google Patents

Description

N 1946- s. H. TOWNER EI'AL ELECTROMAGNETIC RELAY Filed Nov. 6, 1945 Patented Nov. 26, 1946 UNITE STATE AENT *GFMQE ELETRQMAGNETKC RELAY Stanley Herbert Towner and Percy Arthur Childs,

London, England, assignors, by mesne assignments, to International Standard Electric ilor- N. X., a corporation of radiation, New York,

Delaware Application November 6, 1943, Serial No. 509,216 In Great Britain December 23, 1942 8 Claims.

13 The present invention relates to electromagnetic relays and is particularly concerned with the improvement of the magnetic circuitof vibrating relays.

The relays with which the invention is concerned are of the kind in which the armature is carried by an elastic reed adapted to execute free vibrations at some definite frequency, or to be driven by alternating current which is applied to an operating winding and which may have the same frequency as that natural to the reed. The reed hay control contacts which are periodically operated thereby.

The invention is directed to the improvement of the magnetic circuit of the relay whereby the operating winding is enabled to exercise a better control over the reed.

According to the invention, there is provided a magnetic circuit for an electromagnetic relay having an armature carried by a vibratable reed, comprising a core adapted to carry an operating winding or win-clings, a yoke magnetically con nected to the core, and two pole-pieces, one being bifurcated, with two substantially parallel limbs, the other pole-piece and the armature being ar-= ranged between the said parallel limbs, the core, yolse and pole-pieces being composed of magnetic material.

Two el bodiments oi the invention will be described i reference to Figs. 1 and 2 of the ac\ company 1g drawing.

Fig. 1 shows a preferred embodiment. lhe

magnetic circuit of the relay comprises a core l on which any suitable operating winding (not shown) be mounted having a pole-piece shaped in the form of a U with two down-turned limbs 3A and 3B between which is placed the other pole-*plece 5, which is constituted by the end of a portion of reduced width of the yoke which makes contact with the back end or" the core 3.

The vibrating reed is assembled below the yolre 5 by means not shown and carries the armature l which is also placed between the limbs 3A and 3B of one polepicce 2 and is normally spaced away from the pole-pieoe l. All the details l, 2, and i should be made of soft iron or other suitable magnetic material.

The air spacing between the pole-piece 1 and the limbs and of the pole-piece should preferably be large compared with the spacing between the armature l and these limbs, as indicated in Fig. l, in order that the magnetic flux may not be unduly shunted away from the armature. This armature will then lie mainly in the normal path of the magnetic pole-pieces and the reluctance odecreased as the armature approaches piece A l. If a suitable winding core l and is energised with est current, the armature will be attracted towards the polethe polemounted on the piece E: and will ultimately rest thereon. When the energising current is cut oil, the reed will 1 preferably be arranged so that it will hold the armature and reed in the fully deflected position when the winding is continuously energised. This pole-piece assists in the initial attraction of the armature, but has the maximum effect when the air gap is small.

The arrangement of Fig. 1 permits ture to be moved along the oi the reed wlthout appreciably affecting the efiiciency of the magnetic circuit. This feature is valuable, since it allows the vibrating system to be tuned with out impairing the operation of he relay.

Fig. 2 shows a fragmentary sketch of a slightly different arrangement of the armature and polepieces according to the invention, which is exactly the same in principle. The'back ends of the core and yoke 5 may be as shown in Fig. 1, and are not shown in Fig. 2.

The core l is provided with a plain pole-piece it which corresponds in function with the polepiece ii of Fig. 1. A bifurcated pole-piece is provided for the yoke 5 by means or" the blocks lSA and H33 of magnetic material fixed thereto and embracing the" pole-piece l the armature 7 carried by the rec arranged below. It will be evident that the principal difierericebetween Figs. 2 l is that the bifurcated pole-piece is carried by the yoke instead of by the core. As in the case of Fig. l, the air-=gaps between the pole=piece ill and the blocks all and. 1328 should preferably be large cor Jared with the armature air-gaps.

In either case, the limbs 3A, or will always have the same magnetic polarity, so that they constitute a single divided pole piece and not separate pole-pieces It will be evident that the blocks lbs and I33 could, if' desired, be formed integrally with the yoke 5. and in Fig. l, the limbs 3A and 33 could be separate pieces.

What is claimed is:

1. In an electromagnetic device in which a variable flux is produced,means forming a magnetic circuit comprising, a substantially rigid core assembly having a double gap at which the flux divides into two substantially parallel paths, said double gap being formed by a fixed central pole piece positioned between two rigidly connected spaced pole pieces with the gaps being formed on the opposite'sides of the central pole piece, and a vibrating armature formed by an iron piece positioned with one face substantially parallel to one face of said central pole piece and with two opposite edge faces parallel to and spaced from the respective faces of said spaced pole pieces, said iron piece being mounted to vibrate in the planes of said edge faces transversely of the adjacent face of said central pole piece and parallel to the adjacent faces of said spaced pole pieces.

2. In an electromagnetic device, means forming a magnetic circuit having an air gap therein comprising, a rigid core assembly having a double gap at which the flux divides into two parallel paths, said double gap being formed by a central core portion positioned between a pair of parallel side core portion with each of the side core portions having a pole face parallel to and adjacent a pole face of the central core portion whereby the two parallel paths are'respectively from the abovementioned pole faces of the central core portion to the respective pole faces of the side core portions, and a vibratable armature positioned adjacent said central core portion and adapted to vibrate toward and away from said central core portion, said vibratable armature having edge portions which are positioned adjacent said side core portions during the time that the armature is nearest said central core portion whereby a part of the magnetic flux in each of said parallel paths is diverted through said edge portions of said armature.

3. In an electromagnetic relay,,the combination of, a core construction adapted to carry an operating winding, a yoke magnetically coupled to the opposite ends of said core construction and forming a magnetic path for the 1 iagnetic -flux of said core construction, said yoke having two polepiece structures one of which is bifurcated with two parallel limbs having opposing faces and the other of which is positioned adjacent said limbs, and a vibratable armature formed by a movable pole piece carried by a vibrator reed with the movable pole piece positioned at'the edge of the zone between said limbs and mounted to vibrate parallel to the opposing faces of said limbs to and from said other pole-piece structure.

4. A device as described in claim 3 wherein, said birfucated pole-piece structure is formed by a single member attached to one end of said core construction, and wherein said other pole-piece structure is an integral portion of an L-shaped yoke portion attached to the other end of said core construction.

5. A device as described in claim 3 wherein, said movable pole piece is adjustably attached to said vibrator reed whereby the natural frequency of vibration of said vibratable armature may be adjusted.

6. A device as described in claim 3 wherein, Y

said vibratable armature has an elongated vibratable reed attached at one end to said yoke and carries said movable pole pieceadjacent its other end, and wherein the natural frequency of vibration of said vibratable armature may be changed.

7. A device as described in claim 3 wherein, said bifurcated pole-piece structure is formed by a pair of separate pole pieces attached to a yoke frame member and wherein said other pole-piece structure is formed by a single member attached to one end of said core construction.

8. A devic as described in claim 3, wherein said vibrator reed is elongated and is attached 40 to said core at one end and carries said movable core construction and yoke are formed of iron.

STANLEY HERBERT TOWNER. PERCY ARTHUR CHILDS.

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