US3540038A

US3540038A - Multi-color single axis magnetically actuated display or indicating element

Info

Publication number: US3540038A
Application number: US846432A
Authority: US
Inventors: Maurice K Taylor; Donald Winrow
Original assignee: Ferranti Packard Ltd
Current assignee: Ferranti Packard Ltd
Priority date: 1969-07-31
Filing date: 1969-07-31
Publication date: 1970-11-10
Anticipated expiration: 1987-11-10
Also published as: GB1302285A

Description

NOV 10, 1970 L R ET AL 3,54QU38 MULTI-COLOR SINGLE AXIS MAGNETICALLY ACTUATED DISPLAY OR INDICATING ELEMENT Filed July 31, 1969 2 Sheets-Sheet 1 FIG. 1b

Inventor Maurice K.Tay|or 8. Donald Winrow NOV. 10, 1970 TAYLOR ETAL 3,540,038

MULTI-COLOR SINGLE AXIS MAGNETICALLY ACTUATED DISPLAY OR INDICATING ELEMENT Filed July 31, 1969 2 Sheets-Sheet 2 Inventor Maurice K.Taylor & Donald Winrow WM ##MLZ United States Patent US. Cl. 340373 8 Claims ABSTRACT OF THE DISCLOSURE Two independently magnetically actuable elements are mounted on substantially the same axes. These elements may be independently magnetically controlled to present in a predetermined direction a choice of four alternative pieces of information.

This invention relates to an electromagnetic display element adapted under electromagnetic control, exterior to the element, to provide one of a selection of a plurality of, but usually four colors, designs or indications.

It is known to provide a pivotally mounted element of laminar form differently colored or marked on opposite sides and carrying a magnet with a polar axis transverse to the rotation axis of said element, controlled by an exterior selectively reversible electromagnetic field to selectively reverse the position of the element magnet when desired. Thus, in a given viewing direction, two alternative colors or two otherwise differently appearing surfaces may be displayed.

This invention provides, in a preferred aspect, the equivalent of two such laminar elements, each pivotal about an axis relative to their support nearly coincident with the other element axis and each having laminar display or indicating lobes extending on opposite sides of the pivotal axes, and with said lobes interleaved so that lobes from the two laminar members are encountered alternately in a progression about the pivotal axis.

Since adjacent laminar lobes are independently movable and alternate laminar lobes with four elements, opposite laminar lobes with more than four are designed to move together, the laminae may be magnetically controlled so that froma predetermined viewing direction, looking generally toward the pivotal axis, the nearer faces of each of two lobes are seen projecting on each side of the approximately coincident rotation axes when viewed in the viewing direction and extending almost transversely relative thereto, with the other two laminar lobes as near thereto as possible but with their faces occluded by the visible lobes. Thus, there is displayed the color or indication provided by the two exposed faces of the lobes at the front, in the viewing direction. One of the exposed laminar lobes carrying one of the faces exposed in the viewing direction, with its occluded co-moving counterpart, may then be rotated through just less than 180, in a direction to occlude the other exposed face, such movement including an angular distance at the end of its rotation to move through mechanical interference the lobe carrying the just occluded face through a small angular distance so that each laminar lobe has moved to the position of the formerly adjacent lobe in the rotation direction therefrom. Now, two new lobe faces are exposed in the viewing direction and it will be noted that two such faces would have been exposed for either direction of lobe rotation. Moreover, on the completion of a second rotation in the same direction as the first, the lobe sides originally opposite in the viewing direction, will now be exposed in the viewing direction. Thus four colors or different indications may be exposed by per- 3,54%,fi38 Patented Nov. 10, 1970 mutations or combinations of such rotation. The four laminar lobes make as flat an X as possible, with the adjacent lobes approximately symmetrical about the perpendicular to the viewing direction and about the viewing direction itself. Each pair of co-moving lobes mounts and is movable with a magnet having an axis transverse to the pivotal axes and a selectively reversible exterior field is provided corresponding to each of said magnets so that reversal of a magnetic field tends to cause reversal of the position of a pair of laminar lobes through their attached magnets. Since with four alternative colors, it is of material importance in which direction a pair of lobes turn, each pair of lobes in either position are maintained so that the field of the attached magnet is not quite, although nearly, aligned with the exterior field. The direction of misalignment is selected so that on reversal of an exterior field the pivotally mounted magnet is misaligned with the reversed field to move the already exposed face which it controls toward the other exposed face. Because of this slight misalignment, the direction of turn of the lobes when the field reverse is known. It will be noted that the direction of turn of a laminar lobe pair is always so that its exposed surface turns toward the other exposed surface. To ensure that the axes of the rotatable magnets are sufficiently misaligned with their exterior control fields that the sense of turning on exterior field reversal is predetermined; the orientation of the exterior fields in relation to each other and to their corresponding rotatable magnet are arranged so that a lobe pair in either of its rest positions tends to assume the same position as the other lobe pair, but such lobe pairs are, through abutments or stops, designed so that they cannot align closer than approximately twice the desired misalignment angle. Thus both laminar lobe pairs are attempting to line up in the same position, and they each keep the other out of and on opposite sides of the desired position. Because of this misalignment, as soon as an exterior field is reversed, the lobe pair controlled thereby rotates so that its exposed face moves toward the other exposed face, the other lobe pair, no longer restrained, moves so that its magnet aligns with its exterior field. Then the lobe pair subject to the reversed field, rotates sufficiently far with predetermined mechanical interference between the members to push the other lobe pair magnet from its aligned position to misalignment with its exterior field on the opposite side from its former position. Thus the lobes are displaying a new color in the viewing direction and are collectively misaligned to the same extent as before, but are misaligned in opposite senses to their former misaligned position.

The two respective laminar lobes which are to rotate together may be a unitary body carrying a permanent magnet movable therewith. Alternatively one of two c0- rotating laminar lobes may be provided with the permanent magnet and a connection may be used to control the other co-rotating laminar lobe. Any method is useful wherein two relatively rotatable magnetically controlled elements rotatable on substantially coincident axes are each used to control the position of a. pair of laminar lobes which rotate substantially therewith and where one laminar lobe pair is arranged to interfere sufficiently with the other laminar lobe pair that the two corresponding magnets are misaligned with their respective fields, in such a rotational sense that when a field is reversed the corresponding laminar lobe pair is rotated so that the exposed face thereon is rotated toward the other lobe pair exposed face.

Moreover, it will be noted that the construction using two pairs of laminar lobes provides four alternative visually different pieces of information but that six or more different pieces of information may be provided by providing three or more pairs of elements rotatable on approximately the same axis. If provision is made for all laminar pairs to mechanically interfere in their rest positions on each side of the pivotal axis, the laminar 7 pairs arrange themselves so that the magnets corresponding to the nearer lobes in the viewing direction and located on each side of the axis; are each misaligned with their respective exterior fields, so that, on reversal of the exterior field, associated with one of said magnets corresponding to a visible lobe, the corresponding lobe pair moves so that its exposed face moves toward the other exposed face.

Thus as many laminar pairs and twice as many color or information combinations may be provided, as it is possible to mount on approximately coincident physical axes while still allowing suflicient separation or segregation of the exterior magnetic fields so that they affect only the magnet to which they correspond.

In the drawings:

FIGS. la-lc demonstrate schematically the method of obtaining four colors using two pairs of co-moving lobes;

FIGS. 2 and 3 show an embodiment of the four color element; and

FIG. 4 shows an alternative arrangement to that of FIGS. 2 and 3.

In FIG. 3 is shown one embodiment of the invention, where a spindle is mounted on a base, to pivotally mount two

laminar elements

12U and 12L. These elements are each provided with two lobes (here but not necessarily) semicircles or diametrically opposed sides of the pivotal axis, with the lobes divided from each other by radial slots 14 extending from one edge to just past the centre along a diameter and the pivot axis so that they may be interleaved, as shown, with the slots 14 opening in opposite directions toward each other and the slot 14 of each element 12 receiving the diametrical part of the other element 12 aligned with its own slot 14. Each element 12 is, by attached sleeve 20, freely pivotally mounted on the spindle 10, with head or the like 16 as bearings, separating the two elements. Although the spindle supports are not shown, beads 18 are shown at each outer end of the respective sleeves 20 to space each element 12 in its desired location from the spindle supports on the pivotal axis. At each end, remote from the slot, each laminar member 12, is provided with a magnet 22U (the upper magnet), 22L (the lower magnet) having its axis transverse to the pivotal mounting. Each

magnet

22U and 22L which may be of any of a large number of available materials, is, to fit in with the mechanical arrangement shown; formed as an annular ring, and attached by gluing or otherwise to the outside of the sleeve 20. The axes of

magnets

22U and 22L are here selected to align with the plane of the laminar members. Corresponding to each such magnet is an exterior field here created by a pair of pole pieces 24U (upper) and 24L (lower) of the type shown in FIG. 4 joined by a shunt 28 which is here shown as, but is not necessarily, integral with, pole piece 24. Shunt 28 is provided with an energizing winding 30, which is adapted to provide the magnetic flux (selectively in either direction in shunt 28), with shunt 28 of material to join the magnetic circuit between pole pieces 24.

The pole pieces 24 are preferably of permanently but reversibly magnetizable material so that the winding may be pulsed to move corresponding magnet 22 and its associated laminar elements, and after the cessation of the pulse will have sufficient remanent fiux to retain the mag net and elements in position. Such arrangement is described in a number of prior applications and patents including: US. application SN. 592,178 filed Nov. 4, 1968, US. Pat. 3,303,494 issued Feb. 7, 1967 and both assigned to Ferranti-Packard Limited. If desired, the winding may be energized by dual windings as described in the above patent and application.

If, desired, single pole energization, may be used as indicated in the above application and in this event the magnets 22 will be oriented with their axes at to that shown to take into account the fact that the single pole, would be rearward of the display relative to the viewing direction, instead of being, as with the double pole piece, on each side thereof. Moreover, although pulsing with permanently magnetizable pole pieces is recommended, the pole pieces may, if desired, be made of soft iron, in which case the coil 30 would have to be continuously energized during the time when a particular orientation is desired.

The operation of the device will be explained with reference to FIGS. la-lc as well as FIGS. 2 and 3. In FIGS. 111-10 and 3, the magnetic axes of exterior fields created by either upper pole pieces 24U or lower pole pieces 24L are indicated as AA and it will be noted that since the field is reversible, the direction is independent of the sense of energization of either pair of pole pieces. In the embodiment of FIGS. 1a1c, and 2 and 3; it is assumed that the axis of each of the

magnets

22U and 22L is transverse relative to their axis of rotation and in the plane of the laminar lobes. Thus the axis of magnet 22U is in the plane of the lobes of member 12U and the axis of magnet 22L is in the plane of the lobes of member 12L. From FIGS. 1a, 10 and 3 it is seen that the magnetic axis of each magnet 22 (corresponding here, but not necessarily with the plane of its corresponding element 12) attempts to line up with the line AA defining the axes of each of the exterior fields. It is desirable, as hereinafter explained, that such alignment almost but not quite take place. This is prevented either by the provision of stops 36 or by the natural interference of the interleaved material determined, inter alia, by the size of the slots 14. In either event, the closest angular spacing between adjacent laminar lobes is determined in accord with the conflicting criteria that:

On the one hand, it is desirable that the faces of the forward lobes in the viewing direction he, as nearly as possible, perpendicular to the viewing direction, both for general appearance, and also so that the two exposed lobe faces will encompass as large a visual angle as possible. On this basis the minimum angle between adjacent laminar lobes should be as small as possible.

On the other hand, the larger the minimum angle between adjacent lobes, the greater the starting torque when it is desired to rotate a lobe pair by controlling its ex terior field. The angle selected, will be twice the angle between each magnet 22 axis and its exterior field, (sub ject to an alternative to be discussed where the angle selected is twice the average angle between each magnet 22 axis and the exterior field. Four alternative indications in the viewing direction are available with the device as just described. These may be color, as shown, or any other four varieties of visual intelligence. As shown in FIG. la, the two lobe surfaces, facing the viewing direction, are both colored to show blue. The two lobe surfaces facing the axis AA on the right and the two lobe surfaces facing the axis AA on the left of the axis of rotation are respectively colored yellow and black. The two lobe surfaces facing away from the viewing direction are colored red.

When it is desired to switch the color displayed in the viewing direction to black, the exterior field corresponding to lobe pair 12L is reversed. Since magnet 22L was not perfectly aligned with axis AA, the rotation of member 12L must move clockwise as shown in FIG. 1b. Also as shown in FIG. 1b, the movement of member 12L clockwise allows the magnetic axis of magnet 22U (here, in the plane of element 12U) to align with the axis AA and the lobe pair 12U moves clockwise through the small angle necessary'to achieve such alignment.

As member 12L rotates to attempt to again align its magnet 22L with axis AA, the advancing sides of member 12L or its stops 36 contact member 12U. Assuming that the magnetic torques caused by

magnets

12U and 12L are substantially equal, the

members

12U and 12L will again be symmetrically disposed about the axis AA so that the

magnets

22U and 22L will now be symmetrically disposed as shown in FIG. both tending toward but unable to reach alignment with axis AA, with black now displayed in the viewing direction.

It will be obvious that, starting from the position in FIG. 1a, the reversal of the field for magnet 22U would have produced the color yellow in the viewing direction.

It will further be obvious that, starting from FIG. 10, that red may be shown in the viewing direction by reversing the field for magnet 22U. It will further be obvious that red in the viewing direction could have been achieved by rotation in either sense from FIG. 1a by two successive reversals of magnetic fields in order, where reversal for 22U followed by reversal for 22L would produce yellow then red; while reversal for 22L followed by reversal for 22U would produce black then red. It is noted that, for a color change requiring the successive reversal of two different fields, that the second reversal should not take place until the magnet to be acted on in the second reversal has been pushed away from field alignment with axis AA by the other member, (i.e. the movement demonstrated in FIGS. la-lc, initiated by the reversal of the field for 22L must have progressed substantially to the position of FIG. 10 so that the reversal of the field for 22U will only take place after the magnetic axis for 22U has been pushed clockwise from FIG. lb, so that the rotation of member 12U at the time of the second reversal will be ambiguous.

In the previous paragraph is described the operation of switching from an arrangement wherein one color is displayed in the viewing direction to the arrangement where the oppositely disposed color is so displayed. This with the arrangement above described, requires switching of the fieldof each of the magnets 22, successively, with an interval between the two switching operations. If it is desired to be able to switch from one color to the opposite (by opposite is of course meant the color two removed in either rotary direction) without a time interval necessarily occurring between the switching of the two fields. This is achieved by making one of the fields stronger than the other. With this arrangement element magnet axes will not be, in their rest position, symmetrically disposed on opposite sides of respective field axes, but the displacements of the axes of magnets 22 from alignment of their respective exterior fields will be unequal. When it is desired to switch to the adjacent color to the right or the left; one only of the fields is switched, as previously described. When it is desired to switch to an opposite color, it both fields are switched simultaneously or almost simultaneously, then both elements will move so that the displayed faces move toward one another and the elements therefore collide. Collision does not terminate their movement if the torque due to one field is (and this is a criteria of operation) sufiiciently stronger than the other that the element it controls will overpower and move the other element back to its starting point, and then further across its exterior field axis to a position where the overpowered element will then continue to a position almost reversed from its original position. Thus the element controlled by the stronger torque has moved through just less than 180 as with the element 12U of FIG. 10; while the overpowered element moved first in the opposite direction to the other, was then brought back through its original position by the other and, on being moved to the opposite side of its exterior field axis, continued in the same rotary sense as the rotation of the other element on to its rest position through an angle of just less than 180. The above discussion has proceeded on the basis that simultaneous switching may be achieved where one field is made stronger than the other. However, the requirement is that sufficiently stronger torque control one element over the other. This may be achieved either by a stronger field, as described, by a stronger element magnet, by the magnetpole piece spacing or in other conventional magnetic design variants.

Returning to the illustrated embodiment it is not necessary that the axes of

magnets

22U and 22L be aligned respectively with the

members

12U and 12L although this would seem to be the most convenient approach where two pole pieces are supplied for controlling each magnet.

If single pole pieces are used both the exterior magnetic fields will be rotated at to the field AA shown in FIG. 1a and

magnets

22U and 22L will both be rotated 90 in the same sense in relation to their respective lobe pairs 12U and 12L. It will be noted that any other angular orientation of the exterior fields relative to the position shown in FIG. 1a, accompanied by a corresponding sense and amount of angular rotation of the

magnets

22U, 22L relative to the laminar planes they respectively control.

In the embodiment of FIGS. 3 and 4 it will be noted that the slots 14 of the two laminar elements will allow, in a position exhibiting a predetermined color, a small amount of another color through the half portion of the slot 14, visible at both the top and the bottom of the display. FIG. 4 shows an arrangement whereby this may be reduced.

In FIG. 4 there is shown one laminar member comprising two laminar lobes which is a disc 40 uninterrupted by slots. This is connected to a downwardly extending pivot spindle 42 and mounts a magnet 43 having a magnetic axis transverse to spindle 42. Pins 44 are located on each side of disc 40 and spaced therefrom over a central extent to pivotally mount, as shown, lobes 46 having sleeves 48 rotatable on the pins 44. The pins 44 and sleeves 48 are located and designed so that the pivotal axes defined thereby are, as nearly as possible, coincident with the upward projection of pivotal axis 42 but the pivotal axes of lobes 46 converge slightly in a direction upward from pivot 42 as hereinafter discussed (although this convergence is not shown). One of the lobes, here 46A extends upwardly over the upper end of member 48 and mounts on the upper end, a magnet 50. Projecting from the upper end of magnet 50 is a spindle 52 with the magnetic polar axis being arranged to be transverse relative to the spindle 52. The pivotal axis of the lobe 46A is made convergent on the pivot mounting for spindle 52 to ensure that no substantial misalignment in the pivoting of the assembly takes place when the lobe 46A moves relative to the disc 40, it being noted that this is required since the pivotal axis of lobe 46 cannot be made coaxial with pivot 42 in the unslotted form of member 40. An arm 54 extends across the top of disc 40 and mounts a forked member defining tines 56 extending on each side of lobe 46 and in sliding relationship therewith. Magnetically the operation of the device of FIG. 4 is identical to the operation of the device of FIGS. 1-3 but mechanically the operation is different, the visual results being similar but improved. With given exterior

fields controlling magnets

50 and 43, the lobes from a shallow X substantially as in FIG. la or FIG. 10 with the X oriented so that its legs are as close as possible in the viewing direction and widely spread perpendicular thereto. Means are provided, using stops if necessary, to maintain sufiicient angular spacing between adjacent lobes to ensure each magnet is out of alignment with its controlling field to ensure that, on reversal of a field, the exposed lobe face corresponding to the pivotal member whose exterior field is reversed, turns toward the other exposed face; as explained in connection with the embodiment of FIGS. 1-3. Thus if the field corresponding to magnet 43 is reversed, then disc 40 rotates.

Lobe

46A and 46 through fork 56 are maintained against rotation by the unchanged exterior field controlling magnet 50. Thus

lobes

46A and 46 rotate relative to disc 40 but do not rotate relative to the viewing direction except to the extent of being moved across the exterior field during and at the end of the rotation of disc 40 in a similar manner to member 12U of FIGS. 1b and lc. Conversely, when the field controlling magnet 43 is left unchanged and the field affecting magnet 50 is switched, the lobe 46A and, through fork 56, the lobe 46 are both rotated; while the disc 40 is held by magnet 43 against movement except to the extent that disc 40 is moved enough that magnet 43 is moved to the other side of its exterior field axis.

The device of FIG. 4 has the advantage, over the device of FIG. 3, that due to the elimination of slotted elements, the showing in the viewing direction of a color foreign to that which is to be displayed, is greatly lessened.

The design alternative, previously discussed in relation to FIG. 2 where the torque exertable on one element magnet is sufficient to overpower the other, is equally available with the device of FIG. 4 to allow simultaneous switching of the fields for both elements to obtain the opposite color to that displayed.

In both altenratives and in other variants of the invention, to be limited only by the appended claim or claims, there is provided an assembly designed and constructed to provide in a viewing direction, four alternatively selectable colors or four other alternative pieces of visual information.

Only one such assembly for supplying quaternary visual elfects has been shown. However it will be realized that any number of such assemblies may be arranged in close proximity independently controllable to produce a single visual display.

We claim:

1. A display assembly including a pair of laminar discs having two opposed faces;

pivotally mounted on a base to pivot relative thereto and to each other about substantially parallel, nearly coincident axes;

said discs defining laminar lobes on each side of their respective pivotal axes;

arranged so that approximately a half of each said lobes and of each said face is located on each side of each pivotal axis;

each said half face being designed to provide a predetermined optical appearance;

said discs being interleaved to pivot so that adjacent lobes in a rotation direction about the pivot axis are located on different discs;

a magnet mounted on and pivotal with each of said discs;

means exterior to said display assembly, corresponding to each said magnet, designed to provide a selectively reversible magnetic field to control the orientation of its corresponding magnetic member;

the orientation of each said reversible field and of the magnet relative to its corresponding disc, being chosen so that said exterior field tends to orient its respective disc with a pair of said half-faces directed in the viewing direction.

2. Abase,

a pair of members mounted on said 'base, and designed to pivot relative to each other, about substantially parallel, nearly coincident axes;

a magnet mounted for rotation with each of said pivotally mounted members;

each said magnet defining a magnetic axis transverse relative to the pivotal axis;

exterior field forming members corresponding, respectively to each of said magnets, to provide a selectively reversible magnetic field arranged to control, subject to the interference of other pivotally mounted members, the orientation of said magnet and said member;

a pair of laminar lobes, each lobe having oppositely facing display surfaces corresponding to each of said pivotally mounted members, and connected to project on approximately opposite sides therefrom;

the pair of lobes associated with one of said pivotally mounted members being interleaved about said pivotal axes with the lobes associated with the other pivotally mounted member, so that in any position of said pivotally mounted members, in progressing about said pivotal axes, a lobe associated with one pivotally mounted member is encountered alternately with a lobe associated with another pivotally mounted member;

means causing rotation of said laminar lobe pairs in amounts and at times corresponding to the rotation of the corresponding pivotally mounted element;

the orientation of said fields being so related to each other and to the orientation of said magnetic elements that both said lobe pairs tend, each under the influence of pivotally mounted elements of the corresponding exterior field, to assume the same location regardless of the sense of exterior field,

means for maintaining a predetermined minimum angular spacing between lobes tending to assume the same angular position.

3. A base,

a plurality of members mounted to pivot independently of each other on said base about substantially parallel nearly coincident axes;

a magnet mounted for movement with each of said pivotally mounted members;

each said magnet defining a polar axis transverse relative to the pivotal axis;

exterior field forming members corresponding, respectively, to each of said magnets, designed to provide a substantially reversible magnetic field arranged to control, subject to the mechanical interference of other pivotally mounted members, the orientation of the corresponding magnet and its co-moving pivotally mounted member;

a pair of display lobes corresponding to each of said pivotally mounted members and connected for rotation at the same time as the corresponding pivotally mounted member and connected to project on approximately opposite sides of the locus of said nearly coincident axes;

the pair of display lobes associated with each of said pivotally mounted members being cyclically interleaved about said pivotal axes with the display lobes associated with the other pivotally mounted members;

so that, in any position of said elements in progressing about said pivotal axes, lobes associated with different elements are encountered in cyclically repeating order about said axis of rotation,

said exterior field forming members being oriented relative to each other and the mounted magnets being mounted relative to their respective lobe pairs in an arrangement which causes all said lobes to tend to assume one of two diametrically opposed angular positions.

4. A plurality of pairs of laminar lobes;

each pair being arranged to substantially pivot together about approximately coincident axes and to project on substantially diametrically opposite directions therefrom;

the approximately coincident axes of each pair being approximately coincident 'with each other;

said laminae being interleaved so that laminae from different pairs are encountered in cyclically repeating order about the locus of said approximately coincident axes;

a magnet linked to rotate with each said pair;

each said magnet defining an axis transverse to the pivotal axes;

means, exterior to said element, corresponding to each said magnet, for exerting magnetic torque thereon;

said exterior means being so arranged, relative to each other, to cause all of said laminae to tend to assume one of two diametrically opposed angular positions.

5. A device as claimed in claim 1, including means for limiting the approach to alignment of rotationally adjacent lobes to a predetermined minimum angle.

6. A device as claimed in claim 2 including means for limiting the approach to alignment of rotationally adjacent lobes to a predetermined minimum angle.

7. A device as claimed in claim 3 including means for References Cited UNITED STATES PATENTS 3,303,494 2/1967 Taylor 340-373 10 HAROLD I. PITTS, Primary Examiner US. Cl. X. R. 340336, 366, 378