US3774199A - Binary electromagnetic event indicator - Google Patents

Binary electromagnetic event indicator Download PDF

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Publication number
US3774199A
US3774199A US00241232A US3774199DA US3774199A US 3774199 A US3774199 A US 3774199A US 00241232 A US00241232 A US 00241232A US 3774199D A US3774199D A US 3774199DA US 3774199 A US3774199 A US 3774199A
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US
United States
Prior art keywords
indicator
indicating
disc
magnetic
coil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US00241232A
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English (en)
Inventor
W Patterson
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US Philips Corp
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US Philips Corp
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Publication date
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Publication of US3774199A publication Critical patent/US3774199A/en
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B5/00—Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied
    • G08B5/22—Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied using electric transmission; using electromagnetic transmission

Definitions

  • the present invention relates to indicators and, more particularly, to binary magnetic indicators having a non-illuminated contrasting color display.
  • Non-illuminated magnetic displays are known in the prior art.
  • a number of examples of prior art devices employ pivoted rotatable or translatable indicating elements which are actuated by either permanent magnet or electromagnetic devices.
  • the pivoted devices are magnetic and are caused to move by virtue of opposing or attracting magnetic fields. This requirement for pivoting results in unnecessary bulk and complexity in such indicators.
  • Other types of prior art magnetic indicators employ a multi-step actuation sequence to effect the required change of indication in the indicator. These types of devices are similarly excessively complex and economically expensive to manufacture. These prior approaches are also not capable of achieving substantially high speeds in changing of state of the indicator. Many of these devices are also incapable of latching or memory.
  • a binary electromagnetic indicator comprises an electromagnetic element having a ferromagnetic core and at least one coil, permanently magnetized indicating means having flat top and bottom portions and being positioned at one end of the magnetic core and magnetically coupled thereto, the indicating means having distinguishing indicia on top and bottom portions, the indicating means also for indicating one of two conditions.
  • transparent means for covering the indicating means and for providing a limit of travel to said indicating means, and means for supplying a current to the coil to create a magnetic field in the electromagnetic element, the field being opposite to and greater than that of the indicating means, whereby the indicating means is repelled by the field of the magnetic element and, after striking the covering means, flips over and recouples to the magnetic core.
  • electromagnetic unit 14 which has a ferro-magnetic core 20.
  • a permanently magnetized indicating means 22 which has flat top and bottom portions.
  • the indicating means ispositioned at one end of the magnetic core and magnetically coupled thereto.
  • the indicating means normally in the form ofa flat disc, is typically provided with binary indicia. on the flat portions thereof.
  • the indicia are for indicating one of two conditions.
  • Transparent means for covering the indicating means 22 is shown as plastic cover 15.
  • Means are provided, typically current lead in wires 28, for supplying a current to the coil to create a magnetic field in the electromagntic unit.
  • the indicator is basically housed in a non-magnetic case 13 which as formed is open at both ends.
  • the dase material is typically plastic and the case is generally of cylindrical shape. It is preferred that the front or top end of the case be formed with an inwardly extending flange which defines a display window (17) and acts as a shoulder to support a suitable transparent cover 15.
  • This cover 15 preferably is constructed of plastic or glass and may contain a suitable magnifying lens 19 for assisting visibility.
  • Supported within the case or housing 13 and engaging the transparent cover 15 is a bobbin or coil form 10.
  • the cover is typically cemented to flange 4 or mechanically held tight against it by a bobbin 10.
  • the bobbin which is recessed in recess 12 of case 13 may be cemented or mechanically held in place.
  • the electromagnetic unit 14 includes bobbin 10 which has a hollow stem 16 and carries a coil of insulated wire 18. Located in the stern of the bobbin is a magnetizable core 20.
  • the magnetizable core is preferably made of soft iron. However, in some cases where a greater degree of latching or magnetic coupling is required, the core may be made of hardened steel.
  • the top end of the core is generally flush with the bobbin l0 and also contacts the indicating element or magnetic disc 22.
  • the bottom end of the core 20 is flush with the end of bobbin 10. As shown in FIG. 1, the bottom end of the bobbin is double flanged, 24 and 26.
  • Flange 24 acts to support the coil wire while the flange 26 supports lead wire 28 or terminals which may be at tached to the magnetic indicator. Area 30 between the two bottom flanges is intended as a termination point for the coil wire 18 and the output lead wire 28. It may be desirable to retain the electromagnetic unit within the housing via a suitable insulating potting compound.
  • Indicator disc 22 is provided with binary indicia.
  • the indicia consists of two differing colors, one side of disc 22 is one predetermined color, and the other side a distinguishing and different color.
  • Disc 22 is constructed as a permanent magnet having a pair of discrete poles. Typical construction material is ferrite composition with an elastimer binder.
  • the indicating element 22 is confined to a chamber 32 by the transparent cover which is preferably dome shaped.
  • the disc 22 is sized appreciably smaller than the cover so as to fit loosely within the chamber. This allows ample freedom of movement of the disc to enable it to flip and align itself in the magnetic field in the manner to be described below. As shown in FIG. 2, the disc 22 is more or less centrally located and latched upon the core within the cross section of the cover 15.
  • FIGS. 3A G the operation of the magnetic binary indicating element will be described.
  • FIG. 3A the normal rest position of the indicator is shown.
  • Indicating disc 22 is seen to have two magnetic portions, north pole portion 30 and south pole portion 31.
  • the rest position assuming that no current is supplied to the electromagnet, the attraction of the closest permanent pole of disc 22 to the ferromagnetic core will maintain the position of the indicating disc at the core surface.
  • the top surface of the north pole portion of indicating disc 22 is visible through the lens 8 of the covering dome.
  • a change of color is desired, it is effected by applying a DC signal generated by a DC source to lead wires 28 which, in turn, excites electromagnetic unit 14. If this is done in the FIG.
  • the DC signal has a polarity and magnitude of sufficient size, it will cause the coil to produce a magnetic field opposite to and greater than that of the permanent magnetic poles of disc 22.
  • the field is concentrated in ferro-magnetic core so that its upper end becomes (in this case) a south pole, and its lower end, a north pole.
  • the strength of this repelling field causes the disc to move away from the core 20 as shown in FIG. 3B.
  • the relative uniformity of the repelling field causes the disc to initially move toward the lens 8 without flipping.
  • FIG. 3C illustrates the magnetic disc striking the lens which acts as a stop for the disc. If the magnetic field were perfectly balanced (an impossibility in practical situations) the disc would remain pinned to the lens until the DC pulse was removed. Those familiar with trying to balance opposing magnetic forces understand that there is a tendency for one of the elements to slide off to the side. This effect occurs in the present situation.
  • FIG. 3D illustrates this sideward movement as a result of the imbalance in the magnetic field. The disc slides off toward the weakest part of the repelling field.
  • FIG. 3E illustrates the point where the attracting and repelling forces are approximately equal. In this position the magnetic indicating disc 22 is tilted approximately 9 from the starting position.
  • 3F and G illustrate the return of the indicating disc to the start position with north pole 30 now juxtaposed to the south pole 32 of the'electromagnetic core, with 31, the south pole which originally faced away from the lens, being the indicating portion which is visible through the lens 8.
  • the complete cycle of the magnetic indicating device has been shown.
  • the flipped disc will remain in the position shown in FIG. 36 until the core is magnetized within an opposing field to that of the disc. This is done by either using a voltage of opposite polarity applied to lead-in conductors 28 or employing a second winding oppositely wound to the coil 18 to effect the appropriate magnetic relationship.
  • the construction of the present invention is signifcant in that it provides for memory.” That is, if the input signal is removed, the indicator will remain in its changed state. Similarly, input signals of the same polarity cannot change the state of the indicator. Only'a signal of opposite polarity can effect a change of state. This feature can significantly simplify the logic circuitry necessary to operate the device.
  • the binary magnetic indicator is a simple, economic unit which employs no parts subject to frictional wear, and wherein the only moveable unit is the indicating element itself.
  • the device can be made extremely small and is readily adapted to miniaturization. This type of device may be readily used in an array of such devices to effect an appropriate display of alpha/numeric type characters.
  • the device may also be used as a simple indicating element for any parameter which has been converted to a DC electrical signal.
  • a binary electromagnetic indicator comprising:
  • an electromagnetic element having a ferro-magnetic core and at least one coil; permanently magnetized indicating means having fiat top and bottom portions, said means being positioned at one end of the magnetic core and magnetically coupled thereto, said means having distinguishing indicia on top and bottom portions, said means also for indicating one of two conditions;
  • the indicator of claim 1 wherein there is additional coil of said electromagnetic element which when 3 ,7 74, 1 99 5 6 excited by DC current produces a field opposite to that eating disc surface. of a first coil which additional coil is utilized to return said indicating means to the original position.
  • the indicator of claim 1 wherein said transparent mg of most appmxlmately 30 mmlseconds means includes a lens for optically enlarging the indi 5 7.
  • the indicator of claim 1 having a speed of switch-

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Displays For Variable Information Using Movable Means (AREA)
  • Electromagnets (AREA)
US00241232A 1972-04-05 1972-04-05 Binary electromagnetic event indicator Expired - Lifetime US3774199A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US24123272A 1972-04-05 1972-04-05

Publications (1)

Publication Number Publication Date
US3774199A true US3774199A (en) 1973-11-20

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US00241232A Expired - Lifetime US3774199A (en) 1972-04-05 1972-04-05 Binary electromagnetic event indicator

Country Status (7)

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US (1) US3774199A (enrdf_load_stackoverflow)
JP (1) JPS4917698A (enrdf_load_stackoverflow)
CA (1) CA970453A (enrdf_load_stackoverflow)
DE (1) DE2314169A1 (enrdf_load_stackoverflow)
FR (1) FR2179100B1 (enrdf_load_stackoverflow)
GB (1) GB1374066A (enrdf_load_stackoverflow)
NL (1) NL7304526A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902170A (en) * 1974-02-20 1975-08-26 Ralph D Mcelroy Fault indicator for electrical circuits

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0347348U (enrdf_load_stackoverflow) * 1989-09-09 1991-05-01

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3524358A (en) * 1969-02-26 1970-08-18 Electrospace Corp Device for elimination of indicator wheel bounce

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1458189A (fr) * 1965-05-26 1966-11-10 Signaux Entr Electriques Tableau d'affichage perfectionné
US3487403A (en) * 1965-10-06 1969-12-30 Miniature Elect Components Electromagnetic indicator having rotating spheres
US3425055A (en) * 1966-11-29 1969-01-28 Miniature Elect Components Plural magnet latching electromagnetic indicators
FR1538124A (fr) * 1967-09-14 1968-08-30 Plessey Co Ltd Indicateur électromagnétique
US3634857A (en) * 1970-03-24 1972-01-11 Miniature Elect Components Drum indicator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3524358A (en) * 1969-02-26 1970-08-18 Electrospace Corp Device for elimination of indicator wheel bounce

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902170A (en) * 1974-02-20 1975-08-26 Ralph D Mcelroy Fault indicator for electrical circuits

Also Published As

Publication number Publication date
JPS4917698A (enrdf_load_stackoverflow) 1974-02-16
FR2179100A1 (enrdf_load_stackoverflow) 1973-11-16
FR2179100B1 (enrdf_load_stackoverflow) 1977-02-04
DE2314169A1 (de) 1973-10-11
CA970453A (en) 1975-07-01
NL7304526A (enrdf_load_stackoverflow) 1973-10-09
GB1374066A (en) 1974-11-13

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