US3775712A

US3775712A - Latchable magnetic reed switch

Info

Publication number: US3775712A
Application number: US00339718A
Authority: US
Inventors: L Launt
Original assignee: INFORMATION TRANSFER Inc
Current assignee: INFORMATION TRANSFER Inc
Priority date: 1973-03-12
Filing date: 1973-03-12
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27

Abstract

A U-shaped bar of so-called remanent magnetic material serves as a core for actuating one or more magnetic reed switches that are mounted between the legs of the U with their magnetic axes generally parallel with the bight of the U. Two coils are positioned around the bight of the U, one wound upon an axis parallel to the bight, and the other wound on an axis orthogonal to the bight. The switch, or switches are latched selectively and alternately in either their closed or open position, depending on which of the two coils is energized. The condition of the device may be sensed magnetically in a manner similar to the reading of magnetic memory devices.

Description

United States Patent [191 Launt [11 3,775,712 Nov. 27, 1973 LATCHABLE MAGNETIC REED SWITCH [75] ln'ventorz- Larry L. Launt, Livonia, N.Y.

[7-3] Assignce: Information Transfer, Inc.,

Holcomb, NY.

[22] Filed: Mar. 12, 1973 [21] Appl. No.: 339,718

[52 US. Cl. 335/153, 335/183 [51] Int. Cl. H0111 51/27 [58] Field of Search 335/151, 153, 154, 335/152, 183, 266, 267, 268

[56] References Cited UNITED STATES PATENTS 3,211,857 10/1965 Warrington 335/153 X 3,217,122 11/1965 Bernstein 335/153'X 3,364,449 'l/1968 Gould et al. 335/153 3,486,138 12/1969 Chalmers et al 335/153 X Primary Examiner Roy N. Envall, Jr. Attorney-Hoffman Stone [57] ABSTRACT A U-shaped bar of so-called remanent magnetic material serves as a core for actuating one or more magnetic reed switches that are mounted between the legs of the U with their magnetic-axes generally parallel with the bight of the U. Two coils are positioned around the bight of the U, one wound upon an axis parallel to the bight, and the other wound on an axis orthogonal to the bight. The switch, or switches are latched selectively and alternately in either their closed or open position, depending on which of the two coils is energized. The condition of the device may be sensed magnetically in a manner similar to the reading of magnetic memory devices.

5 Claims, 5 Drawing Figures alternate opening and closing responsively to changes in the magnetic conditionof'the core. a r

In the patented device a pair ofcoilsare mounted at opposite respective endsofa straight, bar-like'core of a remanent magnetic material, and thereed switches are juxtaposedwith the core. When the coils are energized simultaneouslyina magnetically aiding 'direction, the core is magnetized. to act-like a single permanent magnet, the opposite ends of the core :being driven to opposite respective. magnetic -polarities, and "the switches are drawn and. held closed. When, however,

the coilsare energized in magnetic opposition :to, ea'ch other, the core is magnetically-divided into two opposed magnets, 'Theendsof the core are bothflf one polarity, andthe polesofthe otherpolarityare near the center'of the core. The switches are then biased and held open. i

Other, more or less similar arrangementshave also 7 been proposed, some using a permanent magnet in place of one of Ketchledgescoils. I

The previous arrangements have been subjectto certain, disadvantages and difficulties, especially :in respect of driving the switches from their closed totheir open positions. In the Ketchledge arrangementgfor example,

one musteither energizeboth coils simultaneously at closely matched energy .values,'or energize one of the coils to a critical'value, else the desiredmagneticsplitting of the core inhalf will not be achievedproperly. The present invention avoids'thisproblem, and provides a switching device of improved versatility, simplicity, reliability, and ease of control. I

Briefly, a switching device according to the invention includes a core of a remanentmagnetic material that in its basic form is U-shaped, although in actual practice preferably I-I-shape'd, resembling two'U-shaped cores in a common plane with theinbightportions integrally joined together. Magnetic reedswitches are. mounted between the legs of the'U, and a'pair of mutually orthogonal coils are mounted upon the "bight ofthe U.

When the coil that is wound on anaxis parallel *to'the bight is energized, the core is magnetized as a simple horseshoe magnet with the flux gap extending between the legs, through the reed switches, and the switches are driven closed. When, however, the coil wound on an axis parallel to the legs of theU is energized, the

core becomes magnetized as a simple bar magnet, the

legs are of the same magnetic polarityfand a'force of repulsion is produced between the opposed reeds'of the switches to open the switches and hold them open.

In the ordinary case, the energizing currentsapplied to the coils to actuate'theswitches-are simply'pulses of "sufficient value and durationto saturate the core. Their magnitude is not critical, except asto a minimum value,

and, so far as the magnetic actionis concerned, his not possible to overdrive the coils. Norisitever desired to -energize both coils simultaneously. One coil actuates the switches to one position and leaves them latched there, and the othercoil actuates the-switches to'the opposite position, and leaves them latched there. The

operation.

arrangementis 'simplerconvenient, and non-critical in Auxillary reed switches may be mounted alongside the legs of the cores for operation in opposite mode from the switches that extend between the legs. Thus, an off-normal-switch may be included, or operation as adouble throw switch may bereadily achieved.

" Finally, the-magnetic condition of the core may be readily sensed'through either-oneof the coils, or a 4 separate sen seT-winding; by'pulse interrogation methods similar to those used for reading magnetic'memory devices, preferablyoneof the non-destructive methods WAR/V n Representative embodiments of the invention will now be described in detail in conjunction with the accomp'anying' drawing,- wherein: f I. FIGS. 1A and 1B are schematic plan views of a typical device according to the invention illustrating the theory of operation on which it is based; I

FIG. 2 is a plan-view of a switching device according to a'first, representative embodiment of the invention; FIG. 3 is aside elevational viewof the device shown in "FIG.- 2; and I.

FIG. 4 is "a plan .view of a' second, and presently preferred embodiment of the invention. As shown in FIGS. 1A and 1B, the core 10 is alternately switched betweena horseshoe condition, FIG.

--lA, and a bar condition, FIG. 1B, by alternatelyenergizing the two

coils

12 and 14 that are mounted on the bight portion 16 of the core orthogonally to each other. Reed switches 18, normally regarded'as the main switches, are mounted between the

legs

20 and 21 of and parallel to the legs. v 1

The core '10.is preferably made of remanent magnetic material such as the alloy known commercially as .Remadur, or certain ferrite compositions, that is capable of remaining magnetically saturated once it .is driven to saturation by energization of one of the coils l2 and 14. Several materials having the desired remanence characteristics are commercially available and well-known. 5 g As shown in FIGS. 2 and 3, a typical switching device according to the invention may comprise a pair of H-

shaped core pieces

30 and 31, each of which consists of two sheets of Remadur alloy about 0.015 inch thick.

- The core pieces are in face to face opposition and spaced apart about 0.1 inch, or just far enough to accommodate the

main reed switches

34 and 35 that are mounted between their

leg portions

32 and 33, respectively, Inmostutilizations three

switches

34 and 35 at The two

coils

12 and 14 are mounted upon the bightportion 37 of the core and are connected to any desired control circuit for selective alternate energization. Y

The instantaneous magnetic condition of thecore maybe ascertained by applying an electrical pulse of relatively small amplitude to one of the coils Hand 14, and sensing the resulting and ensuing electrical effects in that coil or the other one, or in a separate sense tween'the opposed legsof said core with its magnetic axis generally parallel to the bight of said core, and a pair of energizing coils mounted upon the bight of said core, one of said coils having its winding axis parallel to the length of the bight, and the other one of said c'oils havingits winding axis orthogonal to the bight.

with each other and the condition of a particular core ascertained by. the effect on the sense windings immediately following the application of an interrogating pulse to the core of interest.

An alternative embodiment of the invention is shown in FIG.'4. It includes so-called off-normal contacts constituted by an auxilliary pair of

reed switches

40 and 41 mounted alongside the core pieces 44. In this case, to maximize the magnetic flux applied to the off-

normal contacts

40 and 41, the core pieces differ from the

core pieces

30 and 31 shown in FIGS. 2 and 3 in that they include integrally formed tabs 47 extending laterally outwardly at the bight end of each leg. The off-

normal contacts

40 and 41 operate oppositely from the

main contacts

34 and 35, being open when the main contacts are closed, and vice versa.

Switching devices of theinvention do not require reed switches of special design for. the off-normal contacts. Instead, all of the reed switches in thedevices may be of the standard type known commercially as Form A, in which the contacts are normally open, and are closed only in response to magnetic flux passin through them.

What is claimed is:

l. A magnetically controllable switching device comprising a U-shaped core of a remanent magnetic material, a magnetically responsive reed switch mounted be- 2. A switching device according to claim 1 including an auxilliary magnetically responsive reed switch mounted alongside .ofone of the legs of said core and generally parallel .r thereto for actuation in an electrically opposite mode from said first named switch, being open when said first named switch-is closed and vice versa.

3. A switching device according to claim- 1' including an auxilliary winding upon a selected portion of said core for sensing the magnetic. response to said core to i a current of small amplitude and short duration passed through one of said pair of coils.

4. A magnetically controllable switching device comprising an I-l-shaped core of'a remanent magnetic material, -a magnetically responsive reed switch mounted betwen a selected pair of opposed legs of said core with its magnetic axis generally parallel to the cross-bar of the H, and a pair of energizing coils mounted on the cross-bar portion of said core, one ,of said coils being oriented with its winding axis parallel to the leg portions of the core, and the other one of said coils having its winding axis orthogonally thereto.

5. A switching device according to claim 4 including an auxiliary reedswitch juxtaposed with said core laterally outwardly thereof for operation in an electrically opposite mode from said first named switch, being open when said first named switch is closed and vice versa.

Claims

1. A magnetically controllable switching device comprising a Ushaped core of a remanent magnetic material, a magnetically responsive reed switch mounted between the opposed legs of said core with its magnetic axis generally parallel to the bight of said core, and a pair of energizing coils mounted upon the bight of said core, one of said coils having its winding axis parallel to the length of the bight, and the other one of said coils having its winding axis orthogonal to the bight.

2. A switching device according to claim 1 including an auxilliary magnetically responsive reed switch mounted alongside of one of the legs of said core and generally parallel thereto for actuation in an electrically opposite mode from said first named switch, being open when said first named switch is closed and vice versa.

3. A switching device according to claim 1 including an auxilliary winding upon a selected portion of said core for sensing the magnetic response to said core to a current of small amplitude and short duration passed through one of said pair of coils.

4. A magnetically controllable switching device comprising an H-shaped core of a remanent magnetic material, a magnetically responsive reed switch mounted betwen a selected pair of opposed legs of said core with its magnetic axis generally parallel to the cross-bar of the H, and a pair of energizing coils mounted on the cross-bar portion of said core, one of said coils being oriented with its winding axis parallel to the leg portions of the core, and the other one of said coils having its winding axis orthogonally thereto.

5. A switching device according to claim 4 including an auxiliary reed switch juxtaposed with said core laterally outwardly thereof for operation in an electrically opposite mode from said first named switch, being open when said first named switch is closed and vice versa.