US3638150A - Reed relay - Google Patents

Abstract

A reed relay is provided in which the sealed envelope is a tube made of magnetic material instead of glass.

Description

United States Patent Zwobada et al.

REED RELAY Inventors: Rene L. Zwobada, Orsay; Andre Jean Regeffe, Villemomble, both of France International Standard Electric Corporation, New York, N.Y.

Filed: June 19, 1970 Appl. No.: 47,719

Assignee:

Foreign Application Priority Data June 25, 1969 France ..6921308 U.S. Cl ..335/l53 Int. Cl. ...H0lh 51/27 Field of Search ..335/15 l-154 Primary Examiner-Bernard A. Gilheany Assistant Examiner-R. N. Envall, Jr.

AttorneyC. Cornell Remsen, Jr., Walter J. Baum, Paul W. Hemminger, Charles L. Johnson, Jr., James B. Raden, Delbert P. Warner and Marvin M. Chaban [5 7] ABSTRACT A reed relay is provided in which the sealed envelope is a tube made of magnetic material instead of glass.

6 Claims, 9 Drawing Figures REED RELAY The present invention relates to relays with contacts encased in a protective tube alsoknown as sealed contact relays and more commonly known as reed relays.

A description of this type of relay was provided very early in the specification of French Pat. No. 852,275 filed by the applicant on Mar. 28, 1939 under the title: "Electric switching devices." These relays are basically made up of a glass cylindrical casing, in which are sealed, at both ends, reeds the outer prolongation of which serve as terminals and the inner ends of which serve as contacts. The reeds are elastic and magnetic and their ends are coated with a suitable metal to ensure good contact. The airtight casing can contain any inert gas, such as nitrogen or helium. One or several coils around the casing can be energized to close the contacts.

Apart from their corrosion-resistance properties, these relays are advantageous in that they operate rapidly. This ac counts for their widespread use with digital computers and, in particular, as the main components of speech cross-points in telephone exchanges.

Moreover, in telephone exchanges, power is at a premium. This is why speech cross-points which only use power when they change states havebeen developed. We are referring to magnetically held sealed contact cross-points like the ones used in the ESSl telephone system (Electronic Switching System No. I) installed in the USA. by Western Electric and in the Artemis automatic switching equipment installed by the applicant and described in the publication Commutation et Electronique" No. 10, Oct. I965, pages 80 to 89. These relays mainly comprise sealed contacts, reversible permanent magnets, which switch the magnetic stream in the contacts, and energizing coils. They are disadvantageous on the one hand, in that they constitute cumbersome assemblies and, on the other hand, their assembly is a long and therefore costly process. One aim of the invention is to provide for a less cumbersome and less expensive improved cross-point than previous ones. For the purpose of this description, the subassembly constituted by the sealed contacts in their casing will be termed sealed contacts.

According to a feature of the invention, a reed relay comprising an airtight cylindrical casing comprising a remanent magnetic tube with insulating seals at its ends through which the contact reeds are threaded and around which the energizing coils are placed is provided for.

According to another characteristic of the invention, the tube is made of a ferromagnetic alloy with satisfactory remanent induction properties.

Compared with previous known relays, the relay of the invention is smaller, for the thickness of the glass cylinder no longer exists the magnet being located closer to the contact reeds, the gap is smaller.

According to another feature of the invention, the said gap can be made very small by effecting two constrictions in the magnetic tube and by placing the seals outside said constrictions so as to achieve the required electric installation.

Since the magnet is cylindrical, the flux is more concentrated and less leakage occurs. Therefore for a given contacts attraction field and for a given holding field, the flux of the cylindrical magnet can be weaker, i.e., the number of ampereturns required can be smaller, the number of coil turns can be lower thus permitting a reduction in volume of the relay. Finally, as leakage is low, the relays can be placed close to one another.

The aims and characteristics of the present invention will become clear from the following description of embodiment examples, said description being made with reference to the appended drawings in which;

FIG. 1 is a side view, partly in section, showing part of the contact relay device according to the invention.

FIG. 2 is a side view, partly in section, showing a specific embodiment example of sealed contact according to the invention.

FIG. 3 is a side view, partly in section, showing components of another specific embodiment example of a sealed contact according to the invention.

FIG. 4 is a drawing in perspective of specific embodiment example of the sealed contact casing.

FIG. 5 is a side view, partly in section, of a contact relay device incorporating the sealed contact of FIG. 2 and two energized coils.

FIG. 6 is a side view, partly in section, of a contact relay device incorporating the sealed contact of FIG. Zand four energized coils.

FIG. 7 is a side view, partly in section, of a modification in the implementation of the sealed contact casing used in the devices in FIGS. 5 and 6.

FIG. 8 is a side view, partly in section, of another modification of the sealed casing.

FIG. 9 is a side view, partly in section, of a contact relay device according to the invention comprising two pairs of identical reeds placed in a single magnetic cylinder.

The contact relay device shown in FIG. 1 comprises:

a remanent magnetic tube 1 forming a casing and made of ferromagnetic alloy of satisfactory remanence for instance steel, with a 0.6 to 0.7 carbon content, a 0.5 to 0.8 manganese content and a 0.6 to 0.7 silicon content;

two insulating end seals 20 and 2b made for instance of two glass beads;

two reeds 3a and 3b in highly permeable magnetic material which is also good electric conductor, said reeds being sealed in Zaand 2b;

an energizing coil 4.

The inside 5 of the casing constituted by 1, 2a and 2b can be filled with a neutral gas such as nitrogen for example. The outer ends (projecting outside the casing), 60 and 6b, of reeds 3a and 3b form terminals whereas the inner ends, (inside the casing) 7a and 7b, are coated with suitable precious metal so as to ensure the high resistance and longlife of the contact.

The device shown in FIG. 1 operates as follows: the contact situated between ends 7a and 7b of reeds 3a and 3b being open, a current is set up in coil 4, said current being such that the magnetomotive force applied allows for adequate magnetic induction of tube 1 (saturation); said tube then acquires longitudinal magnetization creating a north-south magnet the lines of force of which close themselves, in particular through reeds 3a and 3b and their ends 7a and 7b. Saidends are mutually attracted, and the contact closes; the current, in coil 4 can then be cut, the magnet constituted by tube 1, provided the remanent induction is sufficient, holds the contact in a closed position. To release the relay, i.e., to open the contact, the magnetic field between ends 7a and 7b of reeds 3a and 3b must be suppressed; as soon as this field is suppressed the elasticity causes the reeds to move apart.

A known means consists in feeding a current of decreasing force into coil 4 thus demagnetizing tube 1. Other embodiment examples which make it possible to open and close the contact will be described hereafter.

FIG. 2 provides another embodiment example of a sealed contact according to the invention in which, in the vicinity of the ends of tube 1, two constrictions, 8a and 8b, are made in the said tube. Said constrictions are designed to reduce the gaps between tube 1 and reeds 3a and 3b; the other components remaining in the same layout as in FIG. 1.

Constrictions 8a and 8b can be made as in 8a for instance, by pinching tube 1, or as in 8b by adding a ring in the same material as tube 1 which is forcibly fitted into said tube.

FIG. 3 shows another embodiment example of a sealed contact in which the ends of .tube 1 comprise grooves 9av and 9bv designed to facilitate the locating of beads 2a and 2b during the sealing process. Naturally the placing of reeds 3a and 3b in the cylinder can be facilitated if the reed-bead unit is prepared beforehand.

FIG. 4 shows a tube 1 the ends of which have notches 10a and 10b opening outwards, the notches being diametrically opposite to one another so that the reed-bead unitsthe beads being round except for a small projection on one sidecan be threaded without error into the ends of 1.

FIG. 5 shows a relay device according to 2 in which tube 1 is surrounded by two coils 4a and 4b placed on either side of the sources lla and 11b. As was explained above, the applied magnetomotive force which is the sum of the magnetomotive forces corresponding to sources 11a and 1 lb, causes the magnetic induction of tube 1; said tube becoming longitudinally magnetized thus generating an induction flux along reeds 3a and 3b which come into contact.

"The sources of energizing current 11a and 11b can be short pulses, it'suffices that their amplitude be great enough to provide the magnetization power needed to produce suitable remanent inductiomThis induction is stored in tube 1 and the contact can therefore be closed after the disappearance of the energizing current pulses and in the same way be maintained without a holding current being required for either of coils 4a and 4b.

The releasing of the relay, i.e., the separation of ends 7a and 7b of reeds 3a and 3b, can be achieved by suppressing the magnetization of tube l-or at least by diminishing said magnetization considerably; to do this, coil 4b for example is energized from source llb by a pulse of current of opposite direction to that which caused, as described above, the closing of the contact, but of a smaller amplitude.

Another process to achieve the resetting of the relay consists in energizing, as already indicated, coils 4a and 4b from sources 11a and 11b by short pulses of current, but in this case with pulses which act in opposition, i.e., pulses of opposite polarities.

It can be assumed that inside tubel, before the application of said pulses, the magnetic charges are so distributed that the left part of said tube for instance corresponds to a South Pole and,,conversely, that the right-hand part of said tube bears opposite charges and corresponds to the North Pole; there is therefore a neutral zone in the center of tube 1 where the charges cancel one another out thus it is as if said tube comprised two coupled magnets. The magnetomotive force set up by source 11a is assumed to be sufficient to saturate the mag-' netization of the left part of tube 1; similarly, the magnetomotive force set up by source 11b is assumed to be sufficient to saturate the magnetization of the right part of tube 1.

The two saturated magnetizations are in opposite directions so that when energization via sources 11a and 11b ceases, the two halves of tube 1 are characterized by remanent inductions of the same quantity but in opposite directions; in other words the ends of tube 1, bearing magnetic charges of the same sign,

have the same polarity; the resulting induction in reeds 3a, 3b is practically nil and the reeds move apart.

FIG. 6 shows a relay device comprising a sealed contact, which basically corresponds to the one shown in FIG. 2, in

which tube 1 is surrounded by four coils 4a, 4b, 4c and 4d.

higher number, for instance twice as high, as the number of turns of coils 4c or 44', characterized by N; turns. Coils 4a and 4d, on the one hand, and coils 4c and 4b, on the other hand, are connected in series. The free ends of the assembly in series of 4a and 4d, emerge on the left of the device shown in FIG. 6 by prongs 12a and 12d; similarly the free ends of the assembly in series 4c and 4b emerge on the right of the device shown in FIG. 6 by prongs 12c and 12b. Ends 6a and 6b of reeds 3a and 3b also serve as prongs.

The three prongs 6a, 12a and 12d, on the one hand, the three prongs 6b, 120 and 12b, on the other hand, are held in position using known methods by rigid insulating parts respectively shown in" schematic form by 13a and 13b: they can be solid with the body of tube 1.

The assembly constituted in this way can then be plugged onto a base provided for beforehand and set out, for instance, on printed circuits; prongs 6a, and 12d are plugged onto a first printed circuit, prongs 6b, 120 and 12b onto a second printed circuit.

In a modification of the device according to the invention but not shown in the drawing, the outputs of coils 4d and 4b as well as the output of reed 3b, are extended and brought round the outside of the device into the proximity of coils 4a and 4c and of output prong 6a of reed 3a; the six outputs thus placed close to one another are equipped with prongs 6a and 6b corresponding to the contact reeds of prongs 12a and'l2d, cor

responding to coils in series 4a and 4d; and with prongs 12cand 12b corresponding to coils in series 4c and 4b; these six prongs are held in position by a single rigid insulating part; the arrangement of the prongs can be such that the operation of plugging onto a base, provided for prior to assembly, can be performed without any risk of error as regards connecting.

The device shown in FIG. 6 operates as follows: when the coils assembled in series 4a and 4d (or 40 and 4b) are energized from sources 11a (or 11b) each coil 4d (or 4c) develops a magnetomotive force E proportional to N sufficient to saturate tube 1 in a given direction, whereas the coil associated with an inverted winding-i.e., respectively 4a or 4bdevelops a magnetomotive force E proportional to N ,,in the opposite directiomE is greater than E for approximately:

A pulse of current applied at one of the assemblies of coils in series 4a and 4d for instance-if we imagine that tube .1 is separated into a left-hand part and a right-hand part on which opposite magnetomotive forces respectively act, said forces being generated by coils 4a and 4dcreates saturated magnetizations of opposite direction on the two parts of tube 1.

Thus polarities of the same sign stand at the ends of thesaid tube the two parts of which are crossedby appreciably equal inductions but in opposite directions: once the pulse has been suppressed, the remanent inductions are also in opposite directions and the total induction which travels through reeds 3a and 3b becomes very low. Consequently if ends 7a and 7b of said reeds were in contact, they would move apart and if they stood apart they would remain so,

When current pulses of the same direction, yielded by sources 11a and 11b are simultaneously applied to the two assemblies of coils in series 4a-4d and 4c-4b, there stand on the left-hand part and on the right-hand part of tube 1 equal magnetomotive forces proportional to (N -N and of the same direction; they have a cumulative effect and it is as if a magnetomotive force E proportional to 2 (N,N acting on the whole of tube 1 brought about magnetization saturation with poles of opposite signs appearing at its ends; once the pulse has been suppressed, the remanent induction flux travelling longitudinally, and in the same direction, through reeds 3aand 3b, causes the ends 7a and 7b which bear opposite sign magnetic charges to move together; the contact closes.

The relay device shown in FIG. 6 can be used to advantages in the matrices of cross-points in centralized control switching systems. In such systems, one of the pairs of coils in series 4a-4d for instance, is assembled in series with corresponding coils or the relay constituting one of the rows of the matrix; the other pair of coils in series 4c-4b, is assembled in series with the corresponding coils of the relays constituting one of the columns of the matrix.

In the embodiment examples described heretofore and, in particular in those illustrated by FIGS. 5 and 6, it was assumed that the devices could be imagined as being two magnetically independent parts. Now this is ideally true only, for in practice the induction lines which in the case of the opening of the contacts emerge in opposite directions from the ends of tube 1 (FIG. 5 or 6) are not channeled and are looped via illdefined paths; in some applications if required a magnetic shunt can be provided which is placed at the center of tube 1, on the outer side, and which reduces the effective air reluctance by shunting the various magnetic parts and, consequently reduces the residual induction which travels through reeds 3a and 3b (FIG. 5 and 6) thus promoting the opening of the contact.

This magnetic shunt can be advantageously implemented by modifying as shown in FIG. 7 the outside shape of remanent magnetic tube 1; this modification entails fitting a fairly thin disk 14 of suitable diameter in the middle of the tube. Disk 14 can possibly be equipped with notches to accommodate the wires of the windings.

Moreover, this magnetic shunt-can be implemented without modifying the shape of the remanent magnetic tube 1, by slipping on the said tube around its middle, as shown in FIG. 8, a ring component 15 bearing a highly permeable disk in magnetic material 16.

In some applications of cross-point matrices, several contacts enclosed in a single protective tube are associated and used for a single cross-point.

FIG. 9 is a schematic diagram of a device according to the invention which, enclosed in a single cylindrical casing l' in remanent magnetic material groups two pairs of contact reeds respectively 3'a, 3'b and 3"a, 3"b in highly permeable elastic magnetic material which is also a good conductor of electricity.

Reeds 3'0 and 3"a are sealed in insulating member 2a; reeds 3b and 3"b are sealed in insulating member 2b. The ends outside the casing, 6'a and 6"a, of reeds 3'a and 3"a operate as terminals whereas their inner ends (i.e., inside the casing), Ta and 7 "a are coated with suitable precious metals; similarly, the ends outside the casing, 6'!) and 6"b, of reeds 3'b and 3"b operate as terminals whereas the ends inside the easing, 7b and 7"b are coated with suitable precious metals.

The section of the cylindrical casing 1 can be circular, elliptical or any other shape according to the specific use to which it is to be put.

Said cylindrical casing can obviously be modified as in the layouts shown in FIGS. 2, 3, 4, 7 or 8.

Similarly, it is obvious that multiple sealed contacts like those shown in FIG. 9 can be energized using the same methods and the same associated energizing coils as the single sealed contacts used in the relay devices already described with reference to FIGS. 5 and 6.

Although the principles of the present invention have been described hereinabove with a reference to a particular example of embodiment, it will be clearly understood that the said description has been only made by way of example and does not limit the scope of the invention.

We claim:

1. A contact relay device encased in a protective tube comprising an impervious cylindrical case, a plurality of contact reeds, means sealing said contact reeds through opposite ends of the case to provide extensions outside the case and ends inside the case which operate as contacts, said reeds being elastic and magnetic, the inner ends of said reeds including coatings of suitable contact metal, at least one energizing coil for said reeds wound around said case, said case being formed by a tube made of remanent magnetic material, said tube being closed at its ends by insulating seals through-which said reeds are extended, and said tube including in the vicinity of each of its ends an airgap formed by a constriction along a certain length of the inner diameter of said tube.

2. A device according to claim 1, in which the remanent magnetic material used for said tube is a ferromagnetic alloy.

3. A device according to claim 1, in which said insulating seals, through which said reeds are extended to close the ends of said tube, are formed by beads of insulating material such as glass, each one of said beads being accommodated at an end of said tube in a volume defined by the inner wall and the constriction in the inner diameter of said tube.

4. A device according to claim 1, in which said tube has, at each end, a notch on the outside, the notch at one end being diametrically opposite to the notch at the other end, said notches being used to accommodate small projections on corresgaonding insulating sealing parts.

A device according to claim 1, m WhlCIl said tube IS equipped in its middle with a magnetic shunt directed towards the outside and formed of a projection of said tube shaped like a flat ring.

6. A device according to claim 1, in which said tube has in its middle a magnetic shunt formed by a flat ring of highly permeable magnetic material, said ring being adapted to be slid along said tube.

Claims (6)

1. A contact relay device encased in a protective tube comprising an impervious cylindrical case, a plurality of contact reeds, means sealing said contact reeds through opposite ends of the case to provide extensions outside the case and ends inside the case which operate as contacts, said reeds being elastic and magnetic, the inner ends of said reeds including coatings of suitable contact metal, at least one energizing coil for said reeds wound around said case, said case being formed by a tube made of remanent magnetic material, said tube being closed at its ends by insulating seals through which said reeds are extended, and said tube including in the vicinity of each of its ends an airgap formed by a constriction along a certain length of the inner diameter of said tube.

2. A device according to claim 1, in which the remanent magnetic material used for said tube is a ferromagnetic alloy.

3. A device according to claim 1, in which said insulating seals, through which said reeds are extended to close the ends of said tube, are formed by beads of insulating material such as glass, each one of said beads being accommodated at an end of said tube in a volume defined by the inner wall and the constriction in the inner diameter of said tube.

4. A device according to claim 1, in which said tube has, at each end, a notch on the outside, the notch at one end being diametrically opposite to the notch at the other end, said notches being used to accommodate small projections on corresponding insulating sealing parts.

5. A device according to claim 1, in which said tube is equipped in its middle with a magnetic shunt directed towards the outside and formed of a projection of said tube shaped like a flat ring.

6. A device according to claim 1, in which said tube has in its middle a magnetic shunt formed by a flat ring of highly permeable magnetic material, said ring being adapted to be slid along said tube.

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