US 3868610 A
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United States Patent Salam 1451 Feb. 25, 1975 Primary Examiner-Harold Broome Attorney, Agent, or Firm-Lawrence E. Laubscher  Inventor: Hassan Paddy Abdel Salam,
L d E d f' 57 ABSTRACT  Asslgnee: g g g (UK) Lmmed A coordinate switching device includes an array of on ng an switching elements arranged in rows and columns.  Filed; Nov, 29, 1973 Each element includes a soft iron armature arranged for movement of a portion thereof between magnetic ] App! 420306 pole members so that as the gap between one pole and the armature increases the other gap diminishes.  Foreign Application P i it D t Movement of the armature is arranged to operate Dec. 8, 1972 Great Britain 56794/72 ewheh eehtaete' ehe ef which may he the mature Mar. 30 1973 Great Britain..................:. 15524/73 The meghehe fields necessary to actuate the armature are produced by selective energization of respective 52 us. c1. 335/112 few and eehhhh eehdheters arranged that One  Int. Cl. I-I0lh 67/30 duces fields in opposite Senses in the two gaps while 581 Field of Search 335/112 152 106 108 the ether fields the same sense The Pelee may be on opposite sides of the same end of the arma-  References Cited ture or on the same side of the armature but at opposite ends. The armature may be arranged to be bista- UNITED STATES PATENTS ble so that itsposition is maintained in the absence of 3,471,8[3 10/1969 Neuber 335/152 actuating Currents 3,670,272 6/1972 Braumann et al. 335/112 3,753,176 8/1973 Regnier 335/112 9 Clalms, 10 Drawlng Flgures PATENTEU 3,868,610
SHEET 3 OF 5 Yb1 m1 Yb2 m2 1 SELECTIVE ELECTRICAL SWITCHING MEANS BACKGROUND OF THE INVENTION This invention relates to selective electrical switching means of the electromagnetically operable co-ordinate type wherein selective energization of row and column conductors may selectively effect a large number of desired electrical connections.
' Known arrangements of this kind have suffered from the disadvantage of requiring complex structures for each of the switching elements forming the co-ordinate array and also of including complex arrangements of conductors in order to produce selective actuation of a required switching element.
SUMMARY OF THE INVENTION It is an object of the invention to provide an improved co-ordinate switching arrangement in which a simple structure is employed for each switching element and in which a simple arrangement of row and column conductors may be used to produce selective actuation of a required switching element.
It is a particular object of the invention to produce a co-ordinate switching device in which each switching element includes an armature mounted for movement in relation to spaced pole members so that as the gap between the armature and one pole member is increased, the'gap between the armature and the-other pole member diminishes, and in which actuation of the armature is produced. by energization of conductors associated with the switching element in such a manner that energization of one conductor produces a magnetic flux in the same sense in both of the gaps while energization of the other conductor produces a magnetic flux which is in opposite senses in the two gaps.
BRIEF DESCRIPTION OF THE DRAWINGS:
In the drawings:
FIG. I is a schematic diagramillustrative of one embodiment of coordinate switching device .in accordance with the invention; r l
FIG. 2 is a schematic diagram illustrative of details of switching elements used in the embodiment of FIG. 1;
FIG. 3 is a schematic diagram illustrative of the complete assembly of a switching element of the embodi ment of FIG. 1;
FIG. 4 is a schematic diagram illustrative of another switching element which may be used in an embodiment of the invention;
FIG. 5 is a schematic diagram illustrative of another embodiment of coordinate switching device in accordance with the invention;
FIG. 6 is a cross-sectional view of a portion of the embodiment of FIG. 5, taken along the line F-F in that Figure;
FIG. 7 is a cross-sectional view in a direction perpendicular to that of FIG. 6, taken along line 2-2 in FIG.
FIG. 8 is a schematic diagram illustrative of another form of switching element which may be used in an embodiment of the invention;
FIG. 9 represents an advantageous form of bi-stable armature which may be used in embodiments of the invention; and
FIG. 10 is a schematic diagram illustrative of a further form of switching element which may be used in an embodiment of the invention.
The switch array which is illustrated by FIG. 1 provides four selectively operable switching elements. It will be understood that this number is selected only for convenience in illustration; in practice the number of elements may be varied as desired, within practical limits. The arrangement shown in FIG. 1 includes four pivotally mounted armatures 111, of magnetizable, i.e., soft, ferromagnetic material disposed in two rows and two columns. Each armature is of elongate form and is pivoted about a centrally disposed horizontal axis 4 for movement in a vertical plane, between positions in which it engages with respective fixed contact members (not shown in FIG. I), as described below with reference to FIG. 2. Embracing the armatures of each row is a respective horizontal loop of electrical conductor; the conductors terminate respectively in terminals al, bl, a2, b2, as shown. Each conductor may be a single turn, as shown, or may comprise a plurality of turns, as may be advantageous to suit the source of electrical current which is to be used. Similar vertically disposed conductor loops terminating in terminals cl, d1; 02, d 2, are each associated with a respective column of the array.
In proximity with each armature there is a fixed yoke member 116 of ferromagnetic material, having four poles. This is illustrated in greater detail in FIG. 3, which portrays one element of the array of FIG. 1. FIG. 2 shows further details of the element. Movement of armature 111 is limited by respectivefixed contacts 102, 103, so that a selective electrical connection between the armature and either of the fixed contacts may be produced by appropriate energization of the conductor loops. It is preferable for the armature to be arranged to be bistable, so that a contact once made will remain made until positive action. is taken, to change the armature position. This may be effected by disposing small permanent'ma'gnets 105, 106 adjacent the limiting positions of the armature, or a weight 107 may be attached to the upper end of the armature.
Referring to FIG. 3, armature 111, having ends Illa, lllb is centrally pivoted for movement between contacts 102, 103 in response to energization of conductors 114, 115. Ferromagnetic yoke member 116 comprises a plate portion 117 lying parallel to the plane in which the armature moves. Yoke 116 also carries projecting pole members 1180, 118a, 118b, 1181) extending from the plane of the plate portion to approach the armature, thus providing low reluctance return paths for the flux produced when the conductors 114, ll5 are energised. There are two air gaps associated with the top end 111a of armature 111. One between the left hand side of 111a and pole member 11811 and the other between the right hand side of Illa and pole member 118a. When current is passed through conductor 115 magnetic flux passes across these gaps and is of the same sense, that is, is similarly directed, in the two gaps. When a current is passed through conductor 114, magnetic flux also passes across the two gaps, but is oppositely directed in the two gaps. With currents passing in both conductor 114 and conductor I15 simultaneously, and with appropriate choice of the relative magnitudes and polarities of the currents, the fluxes due to the two currents can be arranged to add in the gap between armature end 111a and pole member' 118a and to cancel in the gap between armature end 111a and pole member 118a, thereby causing armature end llla to move towards pole member 118a.
By again applying both currents but reversing the sense of one of them the fluxes will add in the gap between armature end 111a and pole member 118a and will cancel in the other gap, so that the armature will move back to its original position. A current in one conductor alone will leave the armature position unchanged, however large the current, since flux is generated in both gaps and the armature will be attracted towards the pole which is nearer, i.e., it will be urged towards the stop against which it already rests. The other end 1111), of the armature is similarly acted upon by flux flowing between'it and pole members 1181) and 118 b, so as to add to the torque produced on the armature. It is clear that coordinate selection of the cells may thus be achieved, since a current in one selected horizontal conductor and one selected vertical conductor can cause switching in only one uniquely defined cell, irrespective of whether the switch in the defined cell is being turned on or off.
Thefour yokes 116 in FIG. 1 can, if desired, be made in one piece, for example by casting or by pressing from a single sheet, by including acommon portion I which holds them together.
FIG. 4 illustrates the mode of operation of an alternative form of switch element. A flat yoke body 21a of soft magnetic material, provided with pairs of projecting pole members 21b, 21b and 210, 21c extending perpendicular to the plane of the body, is embraced by orthogonally disposed conductors 22, 23, each of which embraces also other yoke bodies (not shown) which together with yoke body 210 form one row and one column of. an array of switching elements. With each pair of pole members 21b, 21b and 210, 21c is associated a respective armature 24, 25 of soft magnetic material arranged for rotational motion about a common axis 26. These armatures are shown displaced by more than their correct distance from the pole pieces for clarity of illustration.
When conductor 23 is energised by the passage of an electric current, magnetic flux will pass through the air gap-between the left hand portion of armature 24 and pole member 21b and through the air gap between the right hand portion'of armature 24 and pole member 2112. The fluxes in these two air gaps will be in the same sense, When conductor 22 is energised there will again be magnetic fluxes crossing these two gaps, but in this case the flux in one will be in the opposite sense to that in the other. When currents of appropriate relative amplitudes are applied to both conductors the fluxes due to the two currents will add in one gap and will cancel in the other, tending to cause the armature to rotate about its axis 26 so as to reduce the length of that air gap which is carrying the additive fluxes while increasing the length of the other gap. The action of armature 25 relative to pole members 210 and 210 is similar, the only difference being that armature 25 will rotate in the opposite sense to armature 24 during switching. The direction of switching depends on the relative polarities of the two selection currents, and can be reversed by reversing the sense of either of the curarmatures 24, 25. The armatures are connected by means of pairs of torsion spring leads 34, 34' and 35, 35 to pairs of horizontal signal bus bars Xal, Xa'l, Xbl, Xb'l, etc. All the armatures in the array together with all the X conductors and the armature spring leads can be manufactured out of. a single sheet of soft magnetic material alloy by chemical milling. This armature array is supported on an etched glass sheet by bonding the X conductors to the glass. The glass is etched in the areas which are close to the armatures and their supporting spring leads, so as to allow limited movement of the armatures. For convenience in manufacture all X bus bars are advantageously initially joined together outside the zone of the array by a common frame portion of the sheet so that they, together with the armatures, remain as one sheet until the X conductors have been bonded to the glass. After this the support frame is cropped off.
Associated with the two armatures in each cell there are four C-shaped electrically conductive magnetised latching lands, 51, 53, 54, 56, each of which is magnetised so that there is flux across the Cagap. The latching lands together with the vertical signal bus bars Yal, Ybl, Ya2, Yb2 are bonded onto a common sheet of glass, not shown in this diagram. The latching lands and the Y conductors can, if desired, be made by bonding a sheet of soft magnetic material to a sheet of glass and then etching the latching lands and the Y conductor patterns using photo-fabrication techniques.
In FIG. 5 the latching lands are shown above the ar matures. Below each pair of armatures, but not shown in the Figure, there is a respective yoke, i.e.,a yoke under each cell, and energizing windings round the yokes as described with reference to FIG. 4. When the yoke of cell 011 is appropriately selected, the left-hand side of armature 25 will move to come in latching contact with land 54 and the right-hand side of armature 24 .will move to come in latching contact with land 53. Thus conductor Xbl will be connected to conductor Ybl and conductor Xal will be connected to conductor Yal. By reversing one of the selection currents, the pair of connections will be-broken without disturbing any of the other switches in the array. Each of the other switching elements can be operated in a similar manner.
FIG. 6 is a sectional view taken along the line F-F of cell C11 in FIG. 5 and illustrates in detail the complete assembly for one armature of the array illustrated in FIG. 5, in section.
25 is a pivoted armature as it would appear taking section FF in switching element cll in FIG. 5. 210 and 210' are the yoke pole members associated with the armature and conductors 22, 23 are the selection windings associated with the yoke. FIG. 7 is a sectional side elevation, taken along line Z-Zin FIG. 6. X bus bars Xbl, Xb'l are bonded to a glass sheet 27, which is partially etched away at 57 to allow the movement of the armature. Latching lands 54, 56 and Y conductors Yal, Ybl are shown in FIG. 6, and are bonded to a glass sheet 28, which is spaced from sheet 27 by convenient means, not shown. Land 54 is connected electrically to conductor Yal by means of metal portion 55, but land 56 is electrically isolated from the Y conductors.
Thus with the armatures in the positions shown in FIGS. 6 and 7, conductor Xbl is connected to conductor Ybl. By appropriate energisation of the selection conductors 22, 23 the armature can be switched to the other position, on which 25 comes in contact with isolated land 56, thus breaking the connection. Both lands are magnetised so that the armature is attracted and held by whichever land it is in contact with, and is therefore bistable.
The latching lands are magnetised by placing a permanent magnet close to them. FIG. 7 shows a portion of a magnet 29 above latching land 54 and the preferred magnetisation of that portion. Permanent magnet 29 can be common to the whole array of switches, in which case it is magnetised north south alternately, with the boundaries between the poles aligning with the gaps in the latching lands.
An advantage of the arrangement described with reference to FIGS. 4, 5, 6 and 7 is that all the armatures and their associated interconnections and contact lands are contained in a common space enclosed between the two sheets of glass. They can therefore be protected from atmospheric contamination by bonding the two sheets of glass together all round their perimeter. The sealed unit can easily be separated from the wound yoke array, for replacement of either, should this be necessary at any time.
FIG. 8 shows an embodiment in which an armature 75 is moved between two stable positions by magnetic fields developed by two yokes disposed one on either side of the armature. Two similar U-shaped yoke members 71 and 72 are placed with their projecting limbs or pole members aligned but spaced apart; the spacing between elements shown in the drawing is exaggerated for the sake of clarity in illustration. The two yokes are energized by portions of two common windings 73 and 74, which are shown as being single-turn windings although multi-turn windings may be employed if preferred. Armature 75 is arranged to have a stable position adjacent each yoke and movement of the armature is arranged to produce a required switching'action by operating any convenient form of contacts.
When winding 73 carries a current X of appropriate polarity, a flux Fx passes from the top of yoke 72 to armature 75 and from the bottom of armature 75 to the bottom of yoke 72. Also, a flux F'x passes from the top of yoke member 71 to the armature and from the bottom of the armature to the bottom of yoke member 71.
When winding 74 carries a current Y of appropriate polarity, a flux Fy passes from the top of yoke 72 to armature 75 and from the bottom of armature 75 to the bottom of yoke 72. Also, a flux F'y passes from the bottom of yoke 71 to the bottom of the armature and from the top of the armature to yoke 71. When currents X and Y are applied simultaneously and are of equal amplitude the fluxes Fx and F'y in the two lefthand air gaps cancel,- and the armature is urged towards the two pole members of yoke 72 by the additive action of the fluxes Fx and Fy in the two air gaps between the armature and these poles.
The suspension means employed to provide the two stable positions for the armature may be of any known kind suitable to the purpose, but a preferred armature suspension is shown in FIG. 9. The armature 75 is formed integrally with its suspension means comprising a central resilient support arm 76 flanked by two mutually similar tension members 77, 78 formed by crimping portions of the sheet from which the armature and suspension are made, so that the tension members exert a tensile stress on the armature and thus a compressive force on support arm 76, which produces two stable conditions, one in which support arm 76 is bowed upwardly, as seen in the drawing, and one in which it is bowed downwardly from the plane of the initial sheet from which the armature member is formed. The base of the armature member is clamped by suitable clamping means 79 secured to a frame carrying the switch contacts to be actuated by the movement of the armature.
FIG. 10 illustrates an embodiment using two pole members 81, 82, one on either side of the armature, 83. The armature may be of the bistable type already described with reference to FIG. 9 and could be one of an array of armatures made out of a single sheet of magnetic material. Movement of the armature is arranged to produce a required switching action by operating any convenient form of contacts.
Energisation of conductor 84 with a current of appropriate polarity causes flux to pass from pole member 81 to armature 83 and flux to pass from armature 83 to pole member 82. Thus the flux due to this current is in the same sense in the two air gaps. Energisation of conductor 85 with a current of appropriate polarity causes flux to pass from pole member 81 to armature 83 and flux to pass from pole member 82 to armature 83. Thus flux due to current in 85 is in opposite senses in the two air gaps. With both currents flowing, the resultant fluxes in the gap between pole 81 and the armature are additive and the armature is urged towards pole member 81. By reversing one of the currents the armature can be urged towards pole member 82.
The expression magnetizable material is used in the foregoing specification and in the appended claims to denote a'material of which the residual magnetization, if any, is unchanged by reversal of flux induced therein by the energizing currents.
What is claimed is: I
1. In a coordinate switching device comprising a plurality of selectively operable switching elements disposed in an array comprising rows and columns, each said switching element having an armature of magnetizable material, first and second spaced apart pole members of magnetizable material, a first gap defined between said armature and said first pole member and a second gap defined between said armature and said second pole member, means mounting said armature on the one hand and said first and second pole members on the other hand for relative movement therebetween whereby as the reluctance of said first gap increases with said relative movement that of said second gap diminishes and vice versa, and contact means operated by said relative movement, the improvement wherein there is provided:
a respective first electric circuit associated with each of said rows of switching elements; means selectively energizing each said first electric circuit thereby to develop similarly directed magnetic fields in said first gap and in said second gap of each of the elements in the associated row; a respective second electric circuit associated with each of said columns of switching elements; and means selectively energizing each said second electric circuit thereby to develop oppositely directed magnetic fields in said first gap and in said second gap of each of the elements in the associated column;
whereby said selective energization of one of said first and one of said second circuits produces selective operation of one only of said switching elements. 1
2. The invention claimed in claim 1 wherein each of said circuits comprises a single winding embracing the armatures of all said switching elements of the respective row or'column. l
3. The invention claimed in claim 1 wherein each of said circuits consists of a conductor embracing the pole members of the respective switching element.
4. Theinvention claimed in claim 1 wherein each of said circuits consists of a conductor embracing a yoke member provided with said pole members at spacedapart portions thereof.
5. The invention claimed in claim 1 wherein said gaps are defined between opposite faces of a portion of said armature and respective ones of said pole members.
6. The invention claimed in claim 1 whereinsaid gaps are defined between spaced apart faces on the same side of said armature and respective ones of said pole members.
7. The invention claimed in claim 1 wherein said armature of all of a plurality of said switching elements are formed by spaced apart integral portions of a single member. I
8. The invention claimed in claim 1 wherein said pole members of a plurality of said switching elements are formed by spaced apart integral portions of a single member.
9. In a coordinate switching device comprising a two dimensional array of selectively operable contact sets arranged in rows and columns and each arranged for operation by the movement of an individual armature, each said armature arranged for said movement in response to first and second magnetic fields induced in an individual pole member by selective energization of a respective first electric conductor associated with all the pole members of the row containing the set and a respective second electric conductor associated with all the pole members of the column containing the set, the improvement wherein all said contact sets and said armatures are contained within a common sealed ena closure, and said conductors and said pole members are disposed outside said enclosure.