US3458839A - Locking reed and ball switches and matrices - Google Patents

Description

A. HEETMAN July 29, 1969 LOCKING REED Aim BALL SWITCHES AND MATRICES Filed March 27, 1967 4 Shets-Sheet 1 INVENTOR. ALPHONSUS HEETMAN Zia-AZ.

AGENT July 29, 1969 A. HEETMAN 3,4 8

LOCKING REED AND BALL SWITCHES AND MATRICES Filed March 27. 1967 4 Sheets-Sheet 2 IINVENTOR. AL PHONSUS HEETMAN gLWaKW AGENT July 29, 1969 A. HEETMAN 3,458,839

LOCKING REED AND BALL SWITCHES AND MATRICES Filed March 27, 1967 4 Sheets-Sheet 5 ENTOR. ALPHONSUS HEE N AGENT July 29, 1969 A. HEETMAN 3,453,339

LOCKING REED AND BALL SWITCHES AND MATRICES Filed March 2'7. 1967 4 Sheets-Sheet 4 IsH-i' FIG. 5

INVENTOR. ALPHONSUS HEETMAN United States Patent SWITCHES ABSTRACT OF THE DISCLOSURE An electric switch comprises a permanent magnet mounted on a guiding structure so that it can move between two poles of an electromagnetic system. The magnetic system can be energized by means of coils to move the permanent magnet between the poles, and in the absence of such energization the magnet is held against a pole due to its own field. A switch structure having magnetic contacts is positioned near the permanent magnet, so that in one position of the magnet (i.e. against one pole) the contacts are open and in the other position of the magnet the contacts are closed. The switch structure can be a reed switch or it can consist of a magnetic ball adapted to bridge magnetic contacts.

Theinvention relates to an electric switch comprising at least one set of cooperating magnetically conducting contact members arranged in an envelope and an electromagnetic energization system by the energization of which the said contact members can be set from the open condition in the closed condition, or conversely, the said contact members being maintained in said condition when the energization is removed.

An electric switch of the above described type is known in which two magnetically conducting reeds overlapping each other with their extremities and arranged in an envelope can be made to contact one another or the contact may be interrupted by a pulsatory energization, lasting a few tens of micro seconds, of a yoke consisting of a magnetically conducting material having a certain degree of hysteresis. Such a bistable switch has the drawback that a yoke is required of a particular type of magnetic material while in addition the very short energizatio time is not nescessary for many applications.

It is the object of the invention to provide an electric switch of the type mentioned in the preamble which does not exhibit the above-mentioned drawback, can be manufactured economically, and has further advantages.

The electric switch of the above described type according to the invention is characterized in that by the electro-magnetic energization system a self-supporting movable permanent magnet which is guided in its directio of movement can be made to reciprocate between two poles of the energization system consisting of a magnetically conducting material and determining two end positions of the magnet, the said permanent magnet comprising a permanent pole at each of its extremities facing the said two poles of the energization system and being held against a pole of said system by the field of such a permanent pole in the non-energized condition of the energization system, the said permanent magnet acting in its end positions differently upon a set of cooperating contact members in such manner that a set of cooperating contact members is in the open condition in one end position of the magnet and is in the closed condition in the other end position of the magnet.

7 Claims The energization of such a switch is not critical, the direction thereof determines the position which the magnet will take and consequently the condition of the contacts. The contact pressure is independent of the energization. As aresult of the self-supporting arrangement of the magnet and hence the absence of separate guiding members carried by said magnet, the moving mass is restricted as much as possible. The mechanical structure of such a switch can be very simple.

In a further elaboration of the electric switch according to the invention the magnet surrounds at least one envelope and is slidable along it and the energization system comprises a pole located between the two poles and having an aperture through which the magnet is slidable, the magnetic potential of the two outer poles of the energization system with respect to the inner pole being substantially the same when the yoke is energized. As a result of this a high-speed bistable electro-magnetically operable switch of a compact structure is obtained. This switch is particularly suitable, for example, for use in a so-called coordinate switch.

In order that the invention may readily be carried into effect a few examples thereof will now be described in greater detail, by way of example, with reference to the accompanying drawings.

For a better understanding the examples are not drawn to scale.

FIGURE 1 of the drawings shows a cross-section through a switch according to the invention comprising lug contacts arranged along an operating magnet movable by a bipolar energization system.

. FIGURE 2 partly shows a cross-sectional view and partly a dissyrnmetrical projection of a switch according to the invention having a three-pole yoke and an annular magnet which surrounds an envelope which comprises contact members and a contact ball.

FIGURE 3 is a dissymmetrical projection of a coordinate switch according to the invention comprising magnetic ball contacts which can be operated by an energization system havingmagnetically conducting strips.

FIGURE 4 is an elevation of parts of the three successive plates of an energization system of a coordinate switch according to the invention comprising three plates and a number of transverse strips of magnetically conducting material.

FIGURE 5 is a cross-sectional view of a coordinate switch having an energization system taken along the line V-V of FIGURE 4.

Referring now to FIGURE 1, reference numeral 1 denotes a disc-shaped permanent magnet. The magnet 1 is self-supporting about a magnetically insulating rigidly secured shaft 3 and reciprocable between thepoles 5 and 7 of an energization system. Thepoles 5 and 7 are constituted by the collars ofsleeves 9 and .11, respectively, of magnetically conducting material, for example, soft iron, secured about the shaft 3, for example, by gluing. Thepoles 5 and 7 can be energized bycoils 13 and 15, respectively, arranged around thesleeves 9 and 11, respectively. A number ofenvelopes 17, 19 comprising contact lugs of magnetically conductingmaterial 21, 23, 25, 27 are arranged around the magnet 1. The shaft 3 and theenvelopes 17 and 19 are supported by theplates 29 and 31 of magnetically insulating material.

The operation of the switch is as follows. In the position shown the magnet 1 is held against thepole 5 by its north pole N facing saidpole 5 of the energization system. By the field of the magnet 1 thecontact lugs 25 and 27 are held attracted against one another with their overlapping ends. Thecontact lugs 21 and 23 are open because the field of the magnet 1 produces substantially no magnetic potential difference between said lugs. By the energization of thecoils 13 and 15 the poles and 7 are magnetized to form, for example, north poles. In that case the north pole N of the magnet 1 is repelled by thepole 5 and its south pole S facing thepole 7 is attracted bysaid pole 7 and is displaced until it engages thepole 7. When the energization is removed the magnet 1 remains attracted against thepole 7 as a result of its own field. Thelugs 21 and 23 now contact one another and the contact between thelugs 25 and 27 is interrupted. A short-lasting energization of thecoils 13, in the reverse direction will produce again the position as shown. For convenience a disc-shaped magnet 1 is discussed in this case. To reduce the mass of such a magnet it may be provided, for example, with recesses or even be composed of two coaxial magnetic rings held together by a joint of a light-weight material. By a correct proportioning, design and arrangement of the various components of the switch a relatively much smaller diameter of the magnet disc and a relatively smaller track between the final positions of the magnet disc can be achieved than is shown, for clarity, in the figure.

In FIGURE 2 anannular magnet 33 is self-supporting and movable about anenvelope 35. The final positions of themagnet 33 are determined by twopoles 37 and 39 of a magnetically conductingyoke 41 having three limbs in the form of an E. Themagnet 33 can move through anaperture 42 in athird pole 43 in the central limb of the yoke. On their side facing themagnet 33 thepoles 37 and 39 of theyoke 41 comprisesspacing plates 44, 45 of a shock-absorbing magnetically insulating material, for example, polyethylene terephthalate, against which themagnet 33 resets in its final positions. The central limb of theE-shaped yoke 41 comprises anenergization coil 47. Theenvelope 35 about which themagnet 33 is slidable comprises a number of magnetically conductingcontact members 49, 51, 53, 55 and a magnetically conductingcontact ball 57 which can be operated by the flux inside themagnet 33.

The operation of the switch is as follows. In the position shown and in the non-energized condition of thecoil 47 themagnet 33 remains attracted, by a part of its own flux (holding flux), against thepole 37 which is lined with aspacing plate 44 to restrict the holding flux.

Under the influence of the flux inside themagnet 33 thecontact ball 57 is located against thecontact members 49 and 51 and connects them together. When thecoil 47 is energized in such manner that the holding flux of themagnet 33 is counteracted and exceeded by the energization flux, themagnet 33 disengages thepole 37 and moves towards thepole 39. During this movement the force exerted on themagnet 33 increases more and more as a result of the increasing distance to thepole 37. As a result of this the movement of themagnet 33 from thepole 37 to thepole 39 is a very fast one. Thecontact ball 57 is taken along by the flux insidemagnet 33, and themagnet 33 and theball 57 then take the position denoted in broken lines. Then thecontact members 53 and 55 are connected together and thecontact members 49 and 51 are open. When the energization is removed themagnet 33 is held against thepole 39 by its holding flux emerging from the end face facing that pole. Thecontact ball 57 then remains in the broken-line position. A short-lasting energization of thecoil 47 in the reverse direction will again produce the original condition.

The distance between thepoles 37 and 39 is determined by the proportions of themagnet 33 and the distance which theball 57 has to cover between the oppositely located pairs of contacts. These distances may be small so that the switch may have a compact structure. Thecoil 47 which is shown around the central limb of the yoke may also be divided around the outer limbs or around the parts joining the central limb and the outer limbs. Instead of an envelope with a ball contact, of course, also an envelope with, for example, a lug contact or a sliding armature contact may be used. Themagnet 33 may furthermore comprise, for example, more holes so 4 that a number of contacts can beoperated simultaneously by said magnet.

A switch as described here may be constructed favourably, for example, as a mounting unit for a larger circuit arrangement with printed wiring, for example, a coordinate switch. In that case the energization coil may be constructed from several individually energizable parts.

In FIGURE 3, three groups of magnetically conductingstrips 61, 63, 65; 67, 69, 71; and 73, 75, 77 are arranged in three layers. Thestrips 61, 63, 65, 67, 69 and 71 in the outer layers extend in the same direction and thestrips 73, 75 and 77 in the inner layer extend at right angles to those in the outer layers. All the strips of the outer layers are connected to the same strip 75 (first reference strip) by magnetically conductingtransverse members 79, 81, 83, 85, 87 and 89. The strips of the inner layers are connected to two oppositely locatedstrips 63 and 69 of the outer layer (second and third reference strips) by magnetically conductingtransverse members 91, 93, 83, 85, and 97. Around thetransverse members 79, 81, 87, 89, 91, 93, 95 and 97 which connect all the strips to the reference strips 63, 69, 75, coils are arranged which are diagrammatically shown in the figure and denoted by 99, 101, 103, 105, 107, 109, 111, and 113, respectively. Coils are also arranged around thetransverse members 83 and 85 which connect the reference strips 63, 69 and 75 together which coils are diagrammatically shown and denoted by and 117. The assembly constitutes a central energization system for the intersections of thestrips 61, 63, 65, 67, 69, 71, 73, 75 and 77. At theseintersections envelopes 119, 121, 123 and 125 are arranged which comprise contact members which can be operated by a magnet. Around theenvelopes 119, 121, 123 and 125 self-supportingannular magnets 127, 129, 131 and 133 are slidable throughholes 135, 137, 139 and 141 in the strips of the inner layer under the influence of fields produced by the energization system in a manner as described with reference to FIGURE 2. The position of the annular magnets determines the position of a number of magnetically conductingcontact balls 142, 143, 145 and 147 and hence the condition of the contact members in theenvelopes 119, 121, 123 and 125.

The operation of the above described coordinate switch is as follows:

When the coils are not energized and are in the condition shown, theannular magnets 129, 131 and 133 engage thestrips 61 and 65 and themagnet 127 engages thestrip 67 against which they are held by their own fields. As a result of the magnetically conducting transverse members and the reference strips all the strips have the same magnetic potential. When a pair ofcoils 103, 105 is energized, a magnetic potential difference may be produced between thestrips 71 and 65, respectively, and thefirst reference strip 75. This is eifected in such manner that thestrips 65 and 71 obtain the same magnetic potential with respect to thefirst reference strip 75. Thestrips 77 and 73 now hold the magnetic potential of thefirst reference strip 75 as a result of the magnetic connection via thetransverse members 83 and 85, the reference strips 69 and 63, and thetransverse members 91, 93 and 95, '97. A magnetic potential difference is formed at the area of theenvelopes 123 and 125. The value of this potential difference must be approximately half the value M which is required to cause theannular magnets 131 or 133 to be moved, so approximately /2M. If by means of the pair ofcoils 107, 109 a magnetic potential difference of /2M is applied between the second and third reference strips 63', 69 (which as a result of thetransverse members 83, 85 have the potential of the first reference strip' 75) and thestrip 73, the potential difference between the strips 65'and 71 and 73, respectively, totally becomes This value M causes themagnet 131 to be displaced from thestrip 65 to the strip'71 and thus to vary the position of the contact members in theenvelope 123. The potential difference between thestrips 65 and 71 and 77, respectively, and thestrips 61 and 67, respectively (viareference strip 75 andtransverse members 79 and 81) and 73 now is /2M, so that no influence can be exerted on the position of themagnets 133 and 127. Energization of the pairs ofcoils 103, 105 and 107, 109 in the reverse direction produces a magnetic potential dilference -M between thestrips 65 and 71 and 73, respectively, so that themagnet 131 again returns to the position shown without the other magnets varying their positions.

In order to make the magnetic potential ditference between the strips smaller at the area of the intersections not to be operated so that a larger spreading in the composing elements of the coordinate switch can be permitted, a magnetic pre-energization of, for example, /sM may be set up between the reference strips 75 and 63 and 69, respectively, by means of the pair ofcoils 115, 117 during energizing a desired intersection to be operated, for example, the above described intersection of thestrips 65, 73, 71. The energization of the pairs ofcoils 103, 105 and 107, 109 must then be increased so that they each supply a magnetic potential difference of /3M. A resulting potential dilference of (%M--%M+ /3M)=M is then applied to the intersection to be operated and themagnet 131 in question is displaced while a magnetic potential difference of only or %M is applied to each of the intersections not to be operated. This is a more favourable value than in the above described case of the non-energized condition of thecoils 115, 117 in which the potential dilference between the strips of an intersection not to be operated could be or /2M.

The central arrangement of the reference strips has the advantage that the distance from the reference strips to the intersection and consequently the magnetic resistance remains as small as possible without energization coils having to be provided at several points, for example, as is normal, along the circumference of the switch. Of course, a plurality of contacts may be arranged per intersection which are operated collectively by one magnet.

In FIGURES 4 and 5 three magnetically conductingplates 151, 153, 155 consisting, for example, of soft iron, are spaced apart by magnetically conductingtransverse strips 159. Thecentral plate 153 compriseslugs 161 cut or etched in the plate. Theselugs 161 are separated from theplate 153 for the greater part by anair gap 163. A number ofenvelopes 165 having acontact ball 169 which can be moved by anannular magnet 167 are arranged between theouter plates 151 and 155. Theenvelopes 165 comprise magnetically conductingcontact members 171 with which they are secured in an insulating manner between theouter plates 151, 155 in a manner not shown (for example, soldered with the contact ends in a printed circuit board). Theenvelopes 165 extend throughholes 173 in thelugs 161. Theholes 173 are sufiiciently large so as to pass also theannular magnets 167 movable around theenvelopes 165. Thelugs 161 can be energized by two groups ofcoils 175, 177 which are arranged round thecentral plate 153. Themagnets 167 are held against one of theplates 151 or 153 by their own fields when the coils are not energized, on which plates spacing plates of shock-absorbing magneticallynon-conducting material 179, for example, polyethylene terephthalate, are secured, for example, by gluing.

The operation of the coordinate switch is as follows.

By the simultaneous energization of acoil 175 and a coil 177 alug 161 along which the two coils extend is brought at a sufiiciently high magnetic potential to move, in the manner described with reference to FIGURE 2, amagnet 167 along anenvelope 165 from oneouter plate 151 to the other 155, or conversely, and thus to determine the position of thecorresponding contact ball 169. All the other lugs are than insufficiently energized (in fact they only obtain approximately half of the magnetic potential required therefor) to displace a magnet. So an arbitrary contact may be set in the desired position.

The construction of the switch and the shape of the components is such that a compact, reliable and cheap coordinate switch is obtained which is particularly suitable for use, for example, in a telephone exchange.

Thetransverse strips 159 are necessary to form a magnetic circuit as described with reference to FIGURE 2 but they also have a screening effect so that interference fields as a result of energization of one of the lugs at the area of a number of adjacent lugs are restricted. The number of contacts to be operated per switch may easily be adapted to the needs with this type of switch by suitable choice of the proportions of the plates 15x1, 153, and the transverse strips 159. The groups ofcoils 175, 177 may be located, instead of around thewhole plate 153, for example, also only at the area of thelugs 161 around said lugs and further extend fully along the same side of theplate 153.

When using one of the described coordinate switches, for example, as a preselector in a connection circuit in a telephone exchange, the contacts in a row or column on the same side of the switch (make contacts) may serve for putting through the line, and the contacts of the whole row or column in question on the other side (break contacts) may be connected in series and serve as a separating contact, for example, for a line relay or other detection circuit.

What is claimed is:

1. An electric switch comprising at least one set of magnetically conducting contact members adjacent each other and having open and closed positions; an energization system including a pair of outer poles magnetically coupled and disposed adjacent said contact members; a mediate pole located between said outer poles, magnetically coupled thereto, and having an aperture; coil means for energizing said outer poles equally; a permanent magnet disposed to reciprocate between said outer poles and through said aperture and having permanent poles at each of its extremities for holding said magnet against one of the outer poles when said coil is not energized thereby locking said contacts in one of said positions and whereby energizing said coil causes said magnet to move to the other outer pole locking said contacts in the other of said positions.

2. An electric switch as claimed in claim 1, further comprising a multiple arrangement of contacts each with corresponding magnets, and at least two groups of energization coils, each of the magnets being movable only by the simultaneous energization of at least one coil of each of the groups at will.

3. An electric switch as claimed in claim 2, wherein the energization system comprises a number of magnetically conducting strips arranged regularly in three layers and intersecting one another, the strips in the outer layers being directed equally and those in the central layer being directed at right angles to that of the outer layers, an intersection of three strips located in diiferent layers constituting the operaing poles for said movable magnet, each of the strips of the outer layers being connected by a magnetically conducting transverse member to the same first reference strip of the inner layer and each of the strips of the inner layer being connected by a magnetically conducting transverse member to two oppositely located second and third reference strips of the outer layers, a number of magnetically conducting transverse members being provided with energization coils.

4. An electric switch as claimed in claim 3 wherein the transverse members which connect the three said reference strips are provided with an energization coil.

5. An electric switch as claimed in claim 3, wherein at least one of the said reference strips is arranged centrally in the energization system.

6. An electric switch as claimed in claim 2, wherein the energization system comprises three stacked magnetically conducting plates which [are spaced apart by magnetically conducting transverse strips, the central plate comprising a number of lugs arranged according to a pattern and cut in the plate so as to be partly magnetically insulated therefrom, each of said lugs having a hole for passing said permanent magnet around said contacts and said lugs being energizable by groups of coils arranged on said central plate.

7. An electric switch as claimed in claim 1 wherein said contacts comprise at least one pair of parallel arranged magnetically conducting fixed contact members with which a ball which is movable by the field of the magnet can be contacted.

References Cited UNITED STATES PATENTS 3,284,741 11/1966 Conklin 335-154 3,289,129 11/ 1966 Wessel 335-153 BERNARD A. GILHEANY, Primary Examiner R. N. ENVALL, JR., Assistant Examiner US. Cl. X.R. 335153

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