US3587011A

US3587011A - Reed switch and relay

Info

Publication number: US3587011A
Application number: US1593A
Authority: US
Inventors: Edward A Kurz
Original assignee: PYROFILM CORP
Current assignee: PYROFILM CORP
Priority date: 1970-01-09
Filing date: 1970-01-09
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22

Abstract

Reed relays, both normally closed and normally open circuits, are disclosed as comprising a novel switch section, a bobbin section and a coil means wound on the bobbin section. The switch section and bobbin section can be manufactured independently and thereafter assembled so as to reduce manufacturing costs, facilitate calibration and expedite assembly. The reed relay is structured to provide a total shield around the reed elements to eliminate the effect of random environmental magnetic fields.

Description

' United States Patent 1111 ,587,111 1 [72] Inventor Edward A. Kurz [56] References Cited l-lemlngton, NJ. UNITED STATES PATENTS 25: fi mo 3,214,534 10/1965 Pihl 335/154 7 [45] Patented June 22 3,233,062 2/1966 Dal Branco et al 335/154 X [73] Assignee Pymfllm Corporation Primary Examiner-Bernard A. Gilheany Whippany, NJ. Assistant Examiner-R. N. Envall, Jr

A itarneyPopper, Bain, Bobis & Gilfillan ABSTRACT: Reed relays, both normally closed and normally REED SWITCH AND RELAY open circuits, are disclosed as comprising a novel switch sec- 3 Damn! I tion, a bobbin section and a coil means wound on the bobbin [52] US. Cl 335/151, section. The switch section and bobbin section can be manu- 335/202 factured independently and thereafter assembled so as to [5 1] int. Cl H0lh50/04, reduce manufacturing costs, facilitate calibration and ex- HOlh 51/28 pedite assembly. The reed relay is structured to provide a total [50] Field of Seardi 335/15 l shield around the reed elements to eliminate the efiect of ran- -1S4, 202 dom environmental magnetic fields.

. 1 Reno swrrcn AND RELAY BACKGROUND or THE INVENTION This invention relates to reed switches and reed relays.

Reed switches and relays are well-known devices in electrical circuitry and have experienced widespread use in various areas of the electrical arts.

Developments in the electrical arts wherein reed switches and relays are utilized in low current circuits have resulted in known switches and relays being adversely effected by outside electrical interference, i.e. environmental magnetic forces. Additionally, the fact that such reed switches and relays have been used in relatively great numbers while at the same time being subject to the requirement that they be accurately calibrated has increased the expense of manufacture and cost of assembly. Further, the general trend in the electrical arts toward miniaturization has required the development of progressively smaller relays and switches.

It is the principal object of this invention, therefore, to provide reed switches and reed relays which are inexpensive to manufacture, uncomplicated in construction and of smaller physical size than known relays for accomplishing a comparable function.

It is a further object of the invention to provide totally shielded reed switches and reed relays which are not subject to environmental magnetic forces and therefore particularly useful in applications wherein small currents are accommodated and accuracy is required.

SUMMARY OF THE INVENTION The foregoing and other objects are achieved by a reed relay incorporating a reed switch according to the present invention, one embodiment of which may include a reed switch section having a baseplate, first and second conductor elements connected to terminals and a reed element secured to one of the conductors for engagement with the other conductor, a bobbin section including a base, bobbin and coil terminals, and coil means wound on the bobbin for establishing a magnetic field in response to which the reed is either caused to be displaced to close the reed circuit or cause to be displaced to open the reed circuit, depending upon whether the switch is normally open or closed.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the present invention may be had from the following. detailed description, particularly when considered in the light ,of the attached drawings wherein:

FIG. 1 is a cross-sectional perspective view of normally open embodiment of a reed relay according to the invention;

FIG. 2 is a cross-sectional elevational view of the reed relay of FIG. 1; and

FIG. 3 is a cross-sectional elevational view of a normally closed reed relay according to the invention.

DETAILED DESCRIPTION Referring to F IG. 1, a reed relay according to the invention is designated generally by the reference numeral 10. Switch includes a reed switch section designated generally by the reference numeral 12 (FIG. 2) and a bobbin section designated generally by the reference numeral 14 (FIG. 2).

Switch section 12 comprises a baseplate 15 on which is mounted a pair of

terminal elements

16, 17 which are electrically secured to a pair of

reed elements

19, 20 as is discussed below in detail. Bobbin section 14 comprises a bobbin baseplate 23 on which is mounted a pair of

terminal elements

25, 26 which define connector element for the ends of a wire wound on a tubular bobbin 28 to fonn a magnetic winding 30.

Considering the structures of switch section 12 and bobbin section 14 in detail, and referring particularly to FIG. 2 wherein switch section 12 and bobbin section 14 are shown in axially spaced relation, switch section 12 can be seen to comprise generally circular baseplate 15 having an inner radial surface 32 and an outer radial surface 33. Extending longitudinally axially through baseplate 15 is a bore 35 through which there extends longitudinally the

reed elements

19 and 20. The

reed elements

19, 20 are disposed in spaced relation and rigidly secured to baseplate 15 within bore 35 by a hermetic seal 36 which may be of suitable dielectric material such as glass or ceramic as is generally known in the art. The

outer ends

38, 39 of

reed elements

19, 20 are formed to extend radially and are secured to

terminal elements

16 and 17 respectively by suitable means such as spot welding.

Disposed between the outer radial surface 33 of'baseplate l5 and

tenninal element

16 and 17 is a layer of insulating material 41, which material precludes electrical contact between the material of baseplate l5 and that of

terminals

16 and 17. Similarly, the end of switch section 12 is also covered with a layer of insulating material 43.

Considering

reed elements

19 and 20 in detail, reed element 19 is a single-piece structure having a generally cylindrical end which extends from the above-mentioned connection to terminal 16 and through bores into the inner volume of switch 10 defined by the interior of tubular bobbin 28. The inner end of reed element 19 is flattened for example by upsetting to define a flat portion 45, the lower surface of which defines the contact surface for reed l9.

Reed element 20 is a compound structure comprising a conductor portion 47 having an outer end which is secured to terminal element 17 and an inner end which extends through bore 35 into the inner volume of switch 10. Secured to the extreme inner end of conductor 47 such as by spot welding is a generally flat contact section 49. Contact section 49-is of suffrcient length to extend between the upper surface of conductor surface 47 and the lower surface of flat portion 45. In the embodiment of FIG. 1, baseplate l5, reed element 19 and contact section 49 may be of a suitable high permeability material such as a nickel-iron alloy. The conductor section 47 of reed element 20, however, is of -a low permeability conductive material such as a copper-nickel alloy.

Referring to bobbin section 14, it can be seen that the section comprising bobbin baseplate 23 nonnal to the surface of which is secured a generally tubular bobbin 28. Bobbin baseplate 23 in the embodiment of FIGS. 1 and 2 may be of a suitable high magnetic permeability material such as nickeliron whereas bobbin 28 may be of a low magnetic permeability material or a suitable dielectric material such as glass or ceramic.

Bobbin baseplate 23 includes an inner radial surface 52 and an outer radial surface 53. Mounted on the outer radial surface 53 of bobbin baseplate 23, and separated therefrom by a layer of insulating material 55 are

terminal elements

25 and 26. Additionally, bobbin baseplate 23 is provided with a pair of

openings

57, 58 which accommodate the passage therethrough of the terminal ends of the wire which forms magnetic winding 30 (FIG. 1). In this regard, the terminal ends of the wire from magnetic winding 30 are electrically secured to

terminal elements

25 and 26 by suitable means such as soldering. The outer end of bobbin section 14 is provided with a layer of insulating material 60.

The manufacture of a reed relay 10 according to the invention may be accomplished in the following manner. Initially,

reed elements

19 and 20 may be positioned within bore 35 of baseplate l5 and secured therein in spaced relationship by the provision of hermetic dielectric seals 36 in a manner known to those skilled in the art. Thereafter, layer 41 of insulating material may be positioned on the outer radial surface 33 of baseplate 15. In this regard, the insulating material 41 may be any of the suitable materials known to those skilled in the art, for example, a fiber glass tape with a B-stage (semicured) epoxy impregnation. With respect to insulating layer 41, the tape would be provided as a ring-shaped element, the opening in the center of which being suitable for the passage of

reed elements

19 and 20 therethrough. With the layer 41 of insulating material positioned on baseplate l5,

terminal

16 and 17 would then be positioned in surface-to-surface contact with insulating material 41. Thereafter, the

ends

38 and 39 of reed elements 19 and are bent to extend radially as shown in FIGS. 1 and 2, so as to be in physical engagement withterminals l6 and 17 respectively, and thereafter secured to respective terminals such as by spot welding. With the elements of the switch section so assembled, layer 43 of insulating material, which may be fiber glass, is positioned over the entire end of the switch section after which the section can be finally cured so as to set the epoxy of the insulating material.

Assembly of bobbin section 14 comprises initially the securing of bobbin 28 to the inner radial surface 52 of bobbin baseplate 23. This securing may be accomplished for example by furnace brazing with silver solder, or a like method as is known to those skilledin the art. Thereafter, layer 55 of insulating material is provided over the outer radial surface 53 of bobbin baseplate 23, terminal elements and 26 are positioned thereon, and the section may be cured so as to set the epoxy of the insulating material.

With switch section 12 and bobbin section 14 so assembled, the

flat contact sections

45 and 49 of

reed elements

19 and 20 may be calibrated by any of the known methods. Upon the completion of calibration, bobbin section 14 may be positioned telescopically over

reeds

19 and 20 so that the end of tubular bobbin 28 comes into contact with the inner radial surface 32 of baseplate 15. The joint defined by the bobbin and baseplate is then suitably hermetically sealed by any of the methods known generally in the art.

With switch section 12 and bobbin section 14 so assembled and secured, wire for formingwinding may be electrically secured at one end to terminal 25 through opening 57 in bobbin baseplate 23, wound around the outer surface of bobbin 28 and secured at its other end to terminal element 26 through opening 58 in bobbin baseplate 23. Thereafter, outer layer of insulating material 60 is positioned over the entire end of bobbin section 14 and cured so as to set the epoxy of the insulating material. With the magnetic winding so wound, the entire circumferential surface of reed switch 10 may be provided with an outer-covering 62 (FIG. 1) which may be, for example, a metal foil tape or like material of high magnetic permeability. I

The reed switch of the invention, manufactured in the manner described above, is now ready for operation. Thus, with

terminal elements

16 and 17 in electrical connection with a circuit to be served, the impression of a control voltage on

terminals

25 and 26 will energize winding 30 to generate a magnetic field causing contact sections 45, 59 of reed elements l9 and 20 .to be magnetically attracted thereby closing the switch circuit and allowing the passage of current therethrough,

As was discussed generally above, a desirable feature of the present invention is that a reed relay or switch manufactured in accordance with this teaching may be smaller than reed relays and switches structured in accordance with prior art teachings. This capability for miniaturization is accomplished by the fact that reed element 20 and contact section 49 cooperate to define a U-shaped member which, by reason of its configuration, defines an element of greater effective length than would otherwise be possible in a reed relay of comparable overall length. The increase in effective length allows the contact section 49 to be displaced into contact with contact section 45 in response to the exertion of less magnetic force than would otherwise by required thereby reducing the number of turns required in coil 30 and effecting a substantial reduction in size of the reed relay as compared with reed relays of comparable capacity. A further desirable feature of the present invention is that the contact sections of reed elements l9 and 20 may be substantially isolated from environmental conditions which may induce magnetic forces in

contact sections

45 and 49 by the provision of a substantially total shield of high permeability material around the operating reed elements. In this regard, in the embodiment of FIG. 1 baseplate l5, bobbin baseplate 23, and outer covering 62 are all manufactured of high permeability materials and as such cooperate to define a protective casing around the

reed contact sections

45 and 49. Further, the only portion of the reed elements exposed to environmental conditions and capable of magnetization is that portion of reed element 19 which extends outwardly of bore 35 in baseplate 15. Thus, the effect of environmental magnetism on reed relay 10 is substantially negligible. 2

The

contact sections

45 and 49 of relay 10 can be totally isolated from environmental conditions by structuring both reed elements as compound structures rather than just reed element 20. More specifically, reed element 19 could be provided with a conductor portion manufactured of low permeability, highly conductive material connected to a contact section 45 of high permeability, conductive material. By structuring the reed elements in this manner, no high permeability material would extend outside the confines of the volume defined by

base sections

15 and 23 and bobbin 28.

Another approach to achieving total isolation of the reed elements from environmental conditions can be achieved by structuring the reed elements in the general manner disclosed with respect to the alternative embodiment of reed relay disclosed in FIG. 3.

More particularly, FIG. 3 discloses a reed relay designated generally by reference numeral having exactly the same structure as that of relay 10 with the exception of the reed elements. More specifically, relay 110 is provided with a lower reed element and an upper reed element 119. Upper reed element 119 is structured in exactly the same manner as that described with respect to upper reed element 19 of relay 10, with the exception that the reed element is manufactured from a low permeability, highly conductive material, for example, alloys of copper-nickel. The inner end of upper reed element 119 is flattened to form a contact section which extends longitudinally of the cavity defined within bobbin 128.

Lower reed element 120 comprises a conductor element, manufactured of a low magnetic permeability highly conductive material, having an outer radially extending section 139 and a generally longitudinally extending section 147. One portion of longitudinally extending section 147 is formed to extend away from the longitudinal and toward the extended axis of upper reed element 119. Rigidly secured such as by spot welding to the extreme end of longitudinal element 147 is a contact section 149 which is manufactured of high permeability material. Contact section 149 is of sufficient length to overlap the substantially flat contact section 145 of upper reed sec tion 119 so as to be capable of electrical contact therewith. In this regard, because of the bend in the longitudinal portion 147 of lower reed 120,

contact sections

145 and 149 are normally in contact thus rendering reed relay 110 a normally closed circuit switch. Mounted on the upper surface of longitudinal section 147 between baseplate 115 and the bend in longitudinal section 147 is a substantially flat element 150 of high permeability material. Element 150 defines an attractor element which in the operation of relay 110 may be magnetized to establish an attraction with contact element 149 thereby causing the contact between

elements

145 and 149 to be broken. In this regard, in the operation of relay 110,

terminal sections

116 and 117 are electrically connected to a circuit to be served by relay 110. During normal operation, current flows through the switch in an uninterrupted manner. Upon the introduction of a current through terminals 125, 126 a current through magnetic winding 130 is established thereby generating a magnetic field in the switch.

High permeability sections

149 and 150 are magnetized and attracted, thereby causing contact element 149 to be deflected toward attractor element 150 and away from contact section 145. In this manner the switch circuit is opened and remains so until such time as the forces tending to attract contact section 149 to attractor section 150 are relieved.

With regard to the isolation of the high permeability material elements within relay 110 from environmental magnetic forces, it can be seen that the inner volume of relay 110, as

defined by the cylindrical cavity within bobbin 128 in which reed elements 119' and 120 are mounted, is substantially totally encased by high permeability material. More specifically, bobbin baseplate 123, baseplate 115 and outer covering 160 are all manufactured of high permeability materials so as to shield the structure contained therein from environmental magnetic forces. Additionally, in that

reed elements

119 and 120 are formed of low permeability, highly conductive material with the exception of attractor section 150 and contact section 149, it can be seen that no high permeability material in the switch extends through baseplate 115 to be exposed to environmental conditions. Accordingly reed relay 110 provides a switch wherein the high permeability operating sections are totally isolated from environmental magnetic forces thereby providing a relay of heretofore unheard of reliability, perfonnance capability and repetitive accuracy.

It is to be recognized that although the present invention has been disclosed in terms of a reed relay, a shielded switching section with compound reed elements without the coil-actuating structure may be manufactured within the scope of the invention. Further, it is considered to be manifest that many other modifications and changes can be made to the disclosed embodiments without departing from the spirit and scope of the present invention.

What I claim is:

1. A reed relay comprising:

a switch section including;

a baseplate,

first and second conductor elements secured to and extending through said baseplate; first and second terminal means secured to said first and second conductor elements respectively, and

a reed element secured to said first conductor element in overlapping relation with said second conductor element;

a bobbin section including;

abobbin base, bobbin means secured to said bobbin base, and said baseplate first and second coil terminal means mounted on said bobbin base and electrically insulated therefrom;

coil means wound on said bobbin means, said coil means being electrically connected to said first and second coil terminal means; and wherein said reed element is displaceable to make electrical contact with said second conductor element in response to the passage of electrical current through said coil means.

2. The reed relay of claim 1 and further including high permeability means surrounding said coil means.

3. The reed relay of claim 1 wherein said baseplate, said bobbin base and said second conductor element are of high permeability material, and further including;

high permeability means surrounding said coil means.

4. The reed relay of claim 1 wherein said second conductor element is provided with a reed element for contacting said reed element of said first conductor element.

5. The reed relay of claim 4 wherein said baseplate and said bobbin base are of high permeability material, said first and second conductor elements are of low permeability electrically conductive material, and further including:

high permeability means surrounding said coil means.

6. The reed relay of claim 1 wherein said reed element is conductorelement; insulation means mounted on said outer surface of sard baseplate; and

first and second terminal means secured to the other ends of said first and second conductor elements, respectively, and in surfaceto-surface engagement with said insulation means on said baseplate;

a bobbin section including; 7

a bobbin base having an inner surface and an outer surface;

bobbin means secured to said inner surface of said bobbin base and said inner surface of said baseplate base; insulation means mounted on said outer surface of said bobbin base; first and secondcoil terminal means secured to said insulation means on said bobbin base; and

coil means wound on said bobbin means, said coil means being electrically connected to said first and second coil terminal means.

8. The reed relay of claim 7 wherein said reed element is displaceable to make electrical contact with said second conductor element in response to the passage of electrical current through said coil means.

9. The reed relay of claim 7 wherein said reed element is displaceable out of electrical contact with said second conductor element in response to the passage of electrical current through said coil means.

10. The reed relay of claim 7 and further including high permeability means surrounding said coil means.

11. The reed relay of claim 8 wherein said baseplate, said bobbin base and said second conductor element are of high permeability material, and further including:

high permeability means surrounding said coil means. 12. The reed relay of claim 7 wherein said second conductor element is provided with a reed element for contacting said reed element of said first conductor element.

13. The reed relay of claim 12 wherein said baseplate and said bobbin base are of high permeability material, said first and second conductor elements are of low permeability electrically conductive material, and further including:

high permeability means surrounding said coil means. 14. The reed relay of claim 9 wherein said baseplate and said bobbin base are of high permeability material, said first and second conductors are of low permeability material, and further including:

attractor means secured to said first conductor element between said inner surface of said baseplate andsaid reed element, said attractor means being of high permeability material.

15. The reed relay of claim 14 and further including:

high permeability means surrounding said coil means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION June 22, 1971 Patent No. 3 587 011 I Dated Inventor(s) Edward Z It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 22, cancel "base".

Signed and sealed this 7th day of March 1972.

(SEAL) Attest:

ROBERT GOTTSCHALK EDWARD M FLETCHER ,JR. Attesting Officer Commissioner of Patents USCOMM-DC 50376-P69 FORM PO-105O (10-69] 2 u s covzmmzm PRINTING OFFICE I969 oaes-3a4

Claims

1. A reed relay comprising: a switch section including; a baseplate, first and second conductor elements secured to and extending through said baseplate; first and second terminal means secured to said first and second conductor elements respectively, and a reed element secured to said first conductor element in overlapping relation with said second conductor element; a bobbin section including; a bobbin base, bobbin means secured to said bobbin base, and said baseplate first and second coil terminal means mounted on said bobbin base and electrically insulated therefrom; coil means wound on said bobbin means, said coil means being electrically connected to said first and second coil terminal means; and wherein said reed element is displaceable to make electrical contact with said second conductor element in response to the passage of electrical current through said coil means.

3. The reed relay of claim 1 wherein said baseplate, said bobbin base and said second conductor element are of high permeability material, and further including; high permeability means surrounding said coil means.

5. The reed relay of claim 4 wherein said baseplate and said bobbin base are of high permeability material, said first and second conductor elements are of low permeability electrically conductive material, and further including: high permeability means surrounding said coil means.

6. The reed relay of claim 1 wherein said reed element is secured to said first conductor element at their ends such as to define a U-shaped configuration.

7. A reed relay comprising: a switch section including; a baseplate having an inner surface and an outer surface; first and second conductor elements extending through and secured to said baseplate in electrically insulated spaced relationship; a reed element secured to one end of said first conductor element, said reed element being in overlapping relation with and displaceable to contact one end of said second conductor element; insulation means mounted on said outer surface of said baseplate; and first and second terminal means secured to the other ends of said first and second conductor elements, respectively, and in surface-to-surface engagement with said insulation means on said baseplate; a bobbin section including; a bobbin base having an inner surface and an outer surface; bobbin means secured to said inner surface of said bobbin base and said inner surface of said baseplate base; insulation means mounted on said outer surface of said bobbin base; first and second coil terminal means secured to said insulation means on said bobbin base; and coil means wound on said bobbin means, said coil means being electrically connected to said first and second coil terminal means.

11. The reed relay of claim 8 wherein said baseplate, said bobbin base and said second conductor element are of high permeability material, and further including: high permeability means surrounding said coil means.

12. The reed relay of claim 7 wherein said second conductor element is provided with a reed element for contacting said reed element of said first conductor element.

13. The reed relay of claim 12 wherein said baseplate and said bobbin base are of high permeability material, said first and second conductor elements are of low permeability electrically conductive material, and further including: high permeability means surrounding said coil means.

14. The reed relay of claim 9 wherein said baseplate and said bobbin base are of high permeability material, said first and second conductors are of low permeability material, and further including: attractor means secured to said first conductor element between said inner surface of said baseplate and said reed element, said attractor means being of high permeability material.

15. The reed relay of claim 14 and further including: high permeability means surrounding said coil means.