US2840660A

US2840660A - Double-throw magnetically operated sealed switch

Info

Publication number: US2840660A
Application number: US515983A
Authority: US
Inventors: Adriano C Ducati
Original assignee: G M Giannini & Co Inc
Current assignee: G M Giannini & Co Inc
Priority date: 1955-06-16
Filing date: 1955-06-16
Publication date: 1958-06-24
Anticipated expiration: 1975-06-24

Description

June 24, 1958 A. c. DUCATI 2,8405660 DOUBLE-THROW MAGNETICALLY OPERATED SEALED SWITCH Filed June 16, 1955 26 |20 30 'lll/ll. I

INVENTOR. ADRIANO C. DUCATI BY United States Patent O DOUBLE-THRGW MAGNETICALLY OPERATED SEALED SWITCH Adriano C. Ducati, Milan, Italy, assignor to G. M. Giannini & Co., Inc., Pasadena, Calif.

Application June 16, 1955, Serial No. 515,983

15 Claims. (Cl. 200--87) This invention relates to magnetically operated switches of the type having magnetizable contact members in a sealed glass envelope and which are actuated by a magnetic field created from outside the envelope. More particularly, the invention relates to such switches of single-pole double-throw type.

The invention is described `as embodied in a switch having two fixed position contact elements and one resiliently mounted movable element arranged to engage a1- ternately the two fixed contact members. Thus, under the inuence of an external magnetic eld one electrical circuit is opened and a second electrical circuit is closed simultaneously. The particular features of the construction, whereby actuating power is minimized and reliability is increased, will be set forth in the detailed description which will provide a more complete understanding of the invention and its objects when considered in connection with the accompanying drawings, in which:

Figure 1 is a partial sectional elevation of a switch embodying the invention;

Figure 2 is a perspective view of one part of the switch of Figure 1;

Figure 3 shows a switch having a modified electrode arrangement;

Figure 4 is a perspective View of parts of the switch of Figure 3;

Figure 5 shows another form of electrode and Figure 6 is a partial exploded perspective view of the contact members of the switch of Figure 5.

Figure 1 of the drawing shows a magnetic switch embodying the invention and comprising a pair of elongated

magnetizeable electrodes

10 and 12. These electrodes are of circular cross section and are formed of soft iron or other readily magnetizeable material. These electrodes serve both as magnetic field conductors and as contact members through which electric current will flow.

The electrode 10 is Supported in xed position in one end of a cylindrical glass envelope 14 by a relatively short, stii, Kovar metal lead 16. The lead 16 is secured by soldering, welding or the like to one end of the electrode 10 and extends through a seal in the end wall of the envelope. This provides electrical access to the electrode 10 from outside the envelope and also supports the electrode rigidly in the desired position.

The other electrode 12 is mounted in the other end of the envelope 14 in end-to-end relation to the fixed electrode 10 and in axial alignment therewith. However, this electrode 12 is supported resiliently in the envelope rather than being xed in position. The supporting means for the movable electrode 12 comprises a second Kovar metal lead 18 which extends from the end of the electrode through a glass bead and through a seal in the end wall of the envelope. The glass bead 20 is located relatively close to the envelope end wall and spaced a substantial distance from the end of the electrode 12. Unlike the support lead 16 for the xed electrode 10, the lead 18 is made of such cross section and length that construction pbs Cil

the electrode 12 is supported within the envelope with the desired resiliency to permit the free end 12a to move laterally into and out of Contact with the adjacent free end 10a of the electrode 10. Normally the adjacent free ends of the

electrodes

10 and 12 are spaced slightly apart, out of contact with each other so that the circuit between leads 16 `and 18 is open. These

contact members

10 and 12 substantially iill the internal cross-sectional area of the envelope 14 and have longitudinal surfaces closely adjacent to the inner surface of the envelope.

The glass bead 20, which is sealed in a Kovar metal ring 22, acts as a spacer between the support lead 18 and a supplementary Kovar lead 24 which passes through a second seal in the adjacent envelope end wall and through the bead 20 just inside the ring 22. Alternatively, the ring 22 can be sealed to the walls of the envelope 14 so that instead of being within the envelope, the ring 22 and the bead 20 together forms the end of the envelope. The supplementary lead 24 extends beyond the bead toward the electrode 12 to serve as a contact element normally engaging another contact member 26 which extends rearwardly from the supported end of the movable electrode 12. To insure making positive contact and to provide adequate contact surface area, the

contact members

24 and 26 preferably are provided with contact faces 24a and 26a formed of tungsten or other hard corrosion-resistant material.

The supplementary lead 24 and the electrode extension 26 cooperate to provide a second set of contacts (normally closed) in the switching device. Thus, when the switch is not maguetized, a circuit will be completed through the lead wire 24, the electrode extension 26, the movable electrode 12, and the support lead 18.

The movable electrode 12 and its xed counterpart 10 together constitute a normally open set of contacts which can be made to close by passing electric current through a magnetizing winding 28 which surrounds the envelope 14. The magnetic eld set up by this current will act on the two

electrodes

10 and 12 as armatures, causing them to be attracted toward each other.

The adjacent ends of the

electrodes

10 and 12 are cut off at an angle to form

beveled contact faces

10a and 12a. When the electrodes are coaxially positioned within the envelope, these two faces 10a and 12a are spaced so that there is no electrical connection between them or between the supporting

leads

16 and 18. However, upon magnetization of the electrodes, the attraction between them will cause the movable electrode 12 to be displaced laterally, bringing the faces 10ft and 12a into electrical contact. That is, the resilient support lead 18 will bend, permitting the movable electrode 12 to move radially, thereby moving the free end 12a laterally into contact with the other electrode face 10a. At the same time, the tilting of the electrode 12 will cause the extension 26 to move laterally (upwardly as viewed in the drawing), so that the contact between the lead wire 24 and the electrode 12 will be broken.

Thus, when the switch is magnetized, the circuit through the

contacts

24 and 26 will be opened, and a new circuit will be formed which includes the lead wire 18, the movable electrode 12, the Xed electrode 10, and the lead wire 16. Accordingly, it is seen that the movable electrode 12 serves as the switching pole of a single-pole, doublei throw switch.

It will be noted that the two leads 18 and 24 are coupled rigidly together through the medium of the glass bead 20 which prevents bending of the portion of the lead 1S between the bead 20 and the glass envelope 14. Thus, all of the bending which permits deection of the contact member 12 occurs between the glass bead 20 and the member 12. v

In order to prevent vibration or accidental shock from 3 displacing the movable electrode 12 suliiciently to make contact with the xed electrode or break contact with the lead wire 24, a resilient sleeve 30 preferably is provided. This sleeve, which also minimizes bouncing of the electrode 12 when the switch is magnetized, extends over the adjacent end portions ofthe electrodesltl and 12. The sleeve 30 preferably is formed of silicone r-ubber, although other resilient insulating material can he used. In the present illustrative example, the'sleeve is formed of thin walled tubing, occupying recessed portions of the

electrodes

10 and 12 to preclude shifting.

It will be seen that the movable electrode 12 moves only a small amount to open the contact with the lead wire 24 and Close the Contact with the fixed electrode 10. The sleeve 30 vwill readily deform sufficiently to accommodate the lateral movement of the electrode 12. When the magnetizing field is removed, the electrode 12 will be helped to return to its rest position by this stressing of the sleeve 30, as well as by the restoring force of the support lead 18.

In order to insure making good contact, the contact faces 10a and 12a may be coated with highly conductive contact material, such as silver, tungsten, platinum or the like. To reduce further the possibility of corrosion of the electrodes as Well as arcing at the contacts, the envelope 14 may be evacuated or may be filled with inert gas such as helium or the like. v

The envelope 14 is referred to here as formed of glass, but other impervious non-magnetic materials can be used, For example, the envelope can be formed of non-magnetic metal, such as copper or aluminum, with the leads brought into the envelope through suitable seals of insulating material such as ceramic or glass.

Figures 3 and 4 show a modification of the electrode structure of Figure 1. In this case, a relatively long, semi-circular section of the movable electrode 12 is cut away to provide a recess 31 extending substantially the entire length of the electrode 12. The space thus provided alongside the electrode 12 is utilized to accommodate a supplementary electrode and contact member 32 of readily magnetizable material. This supplementary element is of semi-circular cross-section and forms a rigid magnetizable body of substantial mass spaced close to the envelope wall but without requiring any increase in envelope volume.

The supplementary electrode 32 is held in a substantially fixed position parallel to and spaced slightly from the movable electrode 12 by being welded or otherwise secured to a lead wire 24 fixed to the Kovar metal ring 22 which surrounds the insulating support bead 20. The

lead wire 24 extends from the ring 22 through a suitable seal in the adjacent end of the envelope 14 for exterior electrical access to the supplementary electrode 32.

At or near the free end of the supplementary electrode, the facing surfaces of the movable electrode 12 and of the fixed supplementary electrode 32 preferably are provided with

contact strips

36 and 38 of-suitable highly conductive contact material, such as silver, tungsten, platinum or the like. These contact strips are engaged,V when the switch is not magnetized; i. e., when the movable electrode 12 is in axial alignment with the fixed electrode 1l). This provides one circuit through the switch, extending from t-he support lead 18 through the movable electrode 12, through the Contact strips 38 and 36 and through the supplementary electrode 32 and support lead 24. When the switch is magnetized,'the electrode 12 will move laterally into contact with the fixed electrode 10. This provides one circuit through the switch, extending from the support lead 18 through the movable electrode 12, through the contact strips 3S and 36 and through the supplementary electrode 32 and support lead 24. When the switch is magnetized, the electro-de 12 will move later-V ally into contact with the fixed electrode 10, so that the circuit through the contact strips will be broken. ThUS,

4 as before, the laterally movable electrode 12 serves as the switching pole of a single-pole, double-throw switch.

It is to be noted that the electrode configuration of Figures 3 and 4 has an additional advantage, in that the magnetic field exerts a force on the movable electrode 12 in two ways. As in the switch arrangement of Figure l, the tendency for thevlines of magnetic force to establish a path of lowest reluctance through the switch structure will tend to bring the free electrode ends 10a and 12a into contact in order to minimize the air-gap therebetween. However, the same magnetic field will follow parallel paths through the movable and

supplementary electrodes

12 and 32, magnetizing these two electrodes with like poles adjacent each other. This creates a repelling force between the

electrodes

12 and 32, thereby adding to the force which causes lateral movement of the electrode 12. As before, it is preferable to provide an aligning sleeve of resilient insulating material.

A further embodiment of the present invention is shown in Figures 5 and 6. ln this embodiment, the free end portion of the movable electrode 12 is recessed or notched on opposite sides thereof to form a tongue-like extension having oppositely disposed, flat contact faces 12a and 12b extending parallel with the electrode axis. The adjacent end portion of the fixed electrode 1t) also is provided with a similar but much deeper notch or recess to form a contact face 10a parallel to and normally spaced slightly from the movable electrode contact face 12a. The other movable electrode contact face 12b normally engages a supplementary fixed contact 24 which comprises a non-magnetic wire of Kovar metal or the like. This Contact wire 24 extends through an insulating sleeve 40 in a longitudinal channel in the fixed electrode 10, being held in place at spaced points 42 (see Figure 6) by peening the channel walls over the sleeve 4f), or other suitable means.

Thus, when the movable electrode 12 is coaxially aligned with the fixed electrode 11B (the switch de-rnagnetized), a first circuit will be completed through the contact wire 24, the movable electrode V12 andthe sup porting lead 18. The fixed and

movable electrodes

16 and 12 again constitute the normally open contacts of the switch Which can be brought into engagement at the

faces

10a and 12a by passing current throughV the magnetizing winding 14 to deflect the movable electrode 12 laterally.

A preferred arrangementfor the contact surfaces of the

faces

10a and 12a is illustrated clearly in Figure 6, in which there is shown a strip of metal 36, such as silver, platinum, tungsten or the like, placed across the face 10a of the electrode 10, and a similar strip 38 placed across the face of the electrode 12 at an angle with respect to the strip 36, so that the two strips in effect lie crosswise with respect to each other. These strips of metal may be positioned at an angle of degees with respect to each other, but it is preferred that the two strips are not parallel.

What is claimed is:

l. A magnetically operated switch device comprising an elongated sealed cylindrical envelope of non-magnetic material having two ends and a continuous cylindrical surface extending between said ends, first and second axially-aligned spaced members of magnetizable material within said envelope and having adjacent ends including first and second normally spaced overlapping closely adjacent contact surfaces, said members substantially filling a central portion of said envelope, a first electrically conductive element secured to said first member and extending out through a first end of said envelope, a second electrically conductive element secured to said second member and extending out through a second end of said envelope, at least one of said conductive elements being relatively thin compared With the member to which it is secured and resiliently supporting its member for lateral movement within said envelope of its contact surface toward and away from the other contact surface, a third Contact surface in said envelope normally making electrical connection with the resiliently-supported member and in the same lateral plane as said first and second contact surfaces, a third electrically conductive element extending from said third contact surface out through one of the ends of said envelope, and operating means surrounding the cylindrical surface of said envelope and surrounding said first, second, and third Contact surfaces.

2. A relay switch comprising a cylindrical sealed envelope, a first cylindrical magnetizable Contact member extending longitudinally within said envelope and substantially lling the internal cross-sectional area thereof near one end of said envelope, a second cylindrical magnetizable Contact member extending longitudinally within said envelope spaced endwise from said first contact member and having an end portion substantially filling the internal cross-sectional area of said envelope and being positioned in partially overlapping relationship with said first Contact member, said second contact member being resiliently supported within said envelope to permit lateral displacement of said end portion thereof into engagement with said first contact member, said second contact member having a longitudinal segment cut away providing clearance behind said end portion, a third magnetizable contact member positioned in said envelope and closely adjacent to said longitudinal cut away clearance space of said second contact member and normally in electrical engagement with said second contact member, and a winding around said envelope for magnetizing said first, second, and third contact members, said second and third contact members being caused to repel each other and separate while said first and second contact members attract and engage, whereby they are caused to make Velectrical contact and the electrical contact between said second and third contact members is disengaged.

3. A magnetically operated switch device comprising a relatively long, generally cylindrical sealed envelope, first and second rigid generally cylindrical contact members of magnetizeable material, one in each end of said envelope, said contact members being in axial alignment with each other and with the axis of said envelope, the adjacent ends of said contact members having offset end portions overlapping each other in spaced relationship and carrying normally spaced electrical contact surfaces, the opposite ends of said contact members being relatively widely spaced from each other, a rigid support element fixed to said second contact member and passing out through one end of said envelope, a resilient support ele ment fixed to said first contact member and passing out through the opposite end of said envelope, a supplementary contact member fixed rigidly in said envelope and extending parallel to said first contact member and insulated therefrom, said supplementary Contact member having an electrical lead connected thereto and passing out through said envelope, said supplementary contact member normally engaging said end portion of said first contact member and completing an electrical circuit between said electrical lead and said resilient support and being disengageable therefrom upon lateral movement of said first Contact member toward said second contact member, and magnetic control means outside said envelope for magnetizing said rst and second contact members, thereby causing them to attract each other and engage Vsaid electrical contact surfaces carried by said end portions and simultaneously to disengage said first contact member from said supplementary contact member.

4. A magnetically operable switch device as defined in claim 3, wherein said first and supplementary contact members are in side-by-side relationship, and wherein said supplementary contact member also is of magnetizeable material.

5. A magnetically operable switch device as dened in claim 3, wherein said contact members all are in endto-end relationship in said envelope, and wherein an end portion of said supplementary contact member is in overlapping relationship with the electrical contact surfaces on said end portions of said first and second contact members.

6. A magnetically operable switch device comprising an elongated, generally cylindrical sealed envelope, first and second cylindrical electrodes of magnetizeable material in opposite ends of said envelope, said electrodes having longitudinal axes substantially in alignment with each other, said first and second electrodes being normally concentric with said envelope and of a size substantially filling the cross section of said envelope and having closely spaced, overlapping adjacent ends, a pair of support leads extending through the opposite end walls of said envelope and fixed one to each of said electrodes at the opposite ends of said electrodes, one of said support leads comprising a rigid member supporting said second electrode in fixed position within said envelope, tlie other of said support leads comprising a resilient member supporting said first electrode for lateral tilting movement within said envelope, a supplementary contact electrode fixed in position within said envelope and comprising a rigid lead extending into said envelope parallel to and spaced from said rigid support member and terminating adjacent the supported end of said second electrode, said second electrode having a portion extending into contact with said supplementary Contact electrode and disengageable therefrom upon lateral tilting movement of said second electrode, and magnetic control means outside said envelope for magnetizing said first and second electrodes.

7. A magnetically operated switch device comprising a sealed cylindrical envelope, first and second elongated electrodes of magnetizeable material inside said envelope, said electrodes having a circular cross section and having longitudinal surfaces closely adjacent the inner surface of said envelope and having longitudinal axes substantially in alignment with each other, an elongated supplementary electrode of magnetizeable material fixed in position within said envelope, said first electrode being fixed in position, means resiliently supporting said second electrode and enabling it to move transversely of said axes between a first position engaging said supplementary electrode and spaced from said first electrode to a second position spaced from said supplementary electrode and engaging said first electrode, said second electrode having a semi-circular longitudinal segment thereof cut away to provide a recess which is occupied by said supplementary contact electrode, said supplementary contact electrode providing a magnetizable body of substantial mass close to the envelope wall.

8. A magnetically operable switch device comprising an elongated, generally cylindrical glass envelope, a first electrically conductive magnetizeable electrode supported rigidly in one end portion of said envelope, a second electrically conductive magnetizeable electrode supported resiliently in the other end portion of said envelope for movement transversely of the axis of said envelope, the longitudinal surfaces of said electrodes being closely adjacent the inner surface of said envelope, a third electrically conductive electrode iii said one end portion of said envelope extending parallel to and insulated from said first electrode, said first and third electrodes having end portions which overlap the adjacent end portion of said second electrode, said end portions of said second and third electrodes being in electrical contact with each other, said end portions of said first and second electrodes being in closely spaced relationship to each other, and electromagnetic control means outside said envelope for magnetizing said first and second electrodes to move said second electrode out of contact with said third electrode and into contact with said first electrode.

9. A magnetic switch device as defined in claim 8, wherein said first electrode has a longitudinal channel ..7 therein and wherein said third electrode comprises an insulated contact element disposed in said channel.

10. A relay switch comprising an elongated sealed cylindrical envelope of non-magnetic material having two ends and a continuous cylindrical surface extending between said two ends, a first contact electrode formed of magnetizeable material and extending longitudinally within said envelope, aV first electrically conductive element secured to said first electrode and extending out through said first end of the envelope, a second contact electrode formed of magnetizeable material and extending longitudinally within said envelope and being positioned in partially overlapping relationship and spaced from said first contact electrode, said second electrode being resiliently supported within said envelope to permit lateral displacement of the end portion thereof into engagement with said first contact electrode, a second electrically conductive element secured to said second electrode and extending out through said second end of the envelope, a third contact electrode positioned in said envelope and normally in electrical engagement with said second electrode, a third electrically conductive element secured to said third electrode and extending out through one of said ends and magnetizing means surrounding said cylindrical surface of said envelope and surrounding the overlapping portions of said first and second contact electrodes for magnetizing said first and second contact electrodes whereby said first and second contact electrodes are caused to make electrical contact and the electrical contact between said second and third electrodes is dis- K engaged.

11. A switch as claimed in claim wherein said third electrode has at least one section of magnetizeable material extending parallel with and at least partially overlying said second electrode, said second and third electrodes repelling each other when said first and second electrodes attract each other.

12. A relay switch comprising an elongated sealed envelope of non-magnetic material, a first contact electrode formed of magnetizable material and extending longitudinally within said envelope, a second contact electrode formed of magnetizable material and extending longitudinally within said envelope and being positioned in partially overlapping relationship and spaced from said first contact electrode, said second electrode being resiliently supported within said envelope to permit lateral displacement of the end portion thereof into engagement with said first contact electrode, a support lead secured to one end of said second contact electrode and extending through and being sealed into one end wall of said envelope, a bead of insulating material secured to said support lead within said envelope, a third contact electrode positioned in said envelope and normally in electrical engagement with said second electrode, said third contact electrode being secured to said insulating bead and extending through and being sealed into said end wall of said envelope thereby anchoring said bead in a substantially fixed position within said envelope, and magnetizing means for magnetizing said first and second contact electrodes whereby said first and second contact electrodes are caused to make electrical contact and the electrical contact between said second and third electrodes is disengaged.

13. A switch comprising an elongated sealed envelope of non-magnetic material, a first contact electrode formed of magnetizable material and extending longitudinally Within said envelope, a second Contact electrode formed of magnetizable material and extending longitudinally within said envelope and being positioned in partially overlapping relationship and spaced from said first contact electrode, said second electrode being resiliently supported within said envelope to permit lateral displacement of the end portion thereof into engagement with said first contact electrode, a third contact electrode positioned in said envelope Vand normally in electrical engagement with said second electrode, the axis of said third contact electrode being in the. same plane as the axis of said second electrode, said plane being the plane within which said lateral displacement of said second electrode occurs, and magnetizing means for magnetizing said first and second contact electrodes whereby said rst and second contact electrodes are caused to make electrical contact and the electrical contact between said second and third electrodes is disengaged.

14. A switch comprising an elongated sealed envelope of non-magnetic material, a first contact electrode formed of magnetizable material and extending longitudinally within said envelope, a second contact electrode formed of magnetizable material and extending longitudinally within said envelope and being positioned in partially overlapping relationship and spaced from said first contact electrode, said second electrode being resiliently supported within said envelope to permit lateral displacement of the end portion thereof into engagement with said first contact electrode, a third contact electrode positioned in said envelope and normally in electrical engagement with said second electrode, said third electrode extending longitudinally through said second electrode and including insulating material between said second and third electrodes, and magnetizing means for magnetizing said first and second contact electrodes whereby' said first and second contact electrodes are caused to make electrical contact and the electrical contact between said second and third electrodes is disengaged.

15. A relay switch comprising a cylindrical glass envelope, a first cylindrical iron contact electrode extending longitudinally within said envelope and substantially filling the internal cross-sectional area thereof, a second iron contact electrode extending longitudinally within said envelope and being positioned in partially overlapping relationship and spaced endwise from said first contact electrode, said second electrode being resiliently supported within said envelope to permit lateral displacement of the end portion thereof into engagement with said first contact electrode, a third contact electrode positioned in said envelope and normally in electrical engagement with said second electrode, and a winding around said envelope for magnetizing said first and second contact electrodes whereby they are caused to make electrical contact and the electrical contact between said second and third electrodes is disengaged.

References Cited in the file of this patent UNITED STATES PATENTS 2,264,746 Ellwood Dec. 2, 1941 2,285,479 Whitted June 9, 1942 2,360,941 Eitel et al. Oct. 24, 1944 2,414,476 Mathes Jan. 21, 1947 2,485,024 Vale et al. Oct. 18, 1949 2,696,543 Ellwood Dec. 7, 1954