US3614683A

US3614683A - Multiple-contact glass-sealed dry reed switching device

Info

Publication number: US3614683A
Application number: US771494A
Authority: US
Inventors: David Lee Porter
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1968-10-29
Filing date: 1968-10-29
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19

Abstract

A multiple-contact magnetic glass-sealed dry reed switch has a plurality of radial reeds which are selectively operated to engage or disengage a central disc contact. The reeds and the disc contact are contained within a single sealed envelope or vessel. Pairs of these dry reed switches are utilized to selectively connect attenuator networks in a variable coaxial line attenuator.

Description

United States Patent Inventor David Lee Porter Buena Park, Calif.

Appl. No, 771,494

Filed Oct. 29, 1968 Patented Oct. 19, 1971 Assignee Western Electric Company, Incorporated New York, N.Y.

MULTIPLE-CONTACT GLASS-SEALED DRY REED SWITCHING DEVICE 2 Claims, 8 Drawing Figs.

US. Cl. 335/152, 333/81 R, 335/206 Int. Cl ..H0lh 51/28 Field of Search 335/152,

[56] References Cited UNITED STATES PATENTS 2,264,022 11/1941 Ellwood 335/151 X 2,264,124 11/1941 Schreiner 335/151 X Primary Examiner-Bernard A. Gilheany Assistant Examiner-R. N. Envall, Jr. AttorneysH. J. Winegar, R. P. Miller and S. Gundersen ABSTRACT: A multiple-contact magnetic glass-sealed dry reed switch has a plurality of radial reeds which are selectively operated to engage or disengage a central disc contact. The reeds and the disc contact are contained within a single sealed envelope or vessel. Pairs of these dry reed switches are utilized to selectively connect attenuator networks in a variable coaxia1 line attenuator.

PATENTEDUBT 19 Ian 3.614.683 SHEET 16F 13 .D. L.. PURT'E'R i7" TUENE'H i/v VEN T'UFP I MULTIPLE-CONT ACT GLASS-SEALED DRY REED SWITCHING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is concerned with glass-sealed multiple-contact switching devices and more particularly with compactly packaged, magnetically responsive electrical switching devices having multiple glass-sealed contacts which can be selectively operated. Multiple switching devices of the type described are of interest in any apparatus which requires the selective control of several electrical circuits.

2. Description of the Prior Art In the past, many control devices and circuit arrangements have utilized a plurality of individual dry reed switches, of a type well known in the art, in which each switch included a pair of cooperable reed contacts sealed within and extending through a glass envelope, and operated by a magnetic field. One such arrangement consisted of a radial array of a plurality of the individual switches having one reed contact of each connected by a lead to a common electrical potential such as supplied to a single terminal, a wire, or a surface such as an apparatus chassis or a conductive strip on a printed circuit board. The other reed contact of each reed switch of the array was then connected to an electrical circuit that was to be controlled or utilized to control other devices through the operated reed switches. Contact-operating means such as electromagnets or permanent magnets were used to operate the reed switches sequentially or selectively.

One disadvantage of the prior art is that the plural arrangement of individual reed switches are difficult to fabricate and assemble. A further disadvantage is the lack of compactness resulting from a need of a plurality of two contact reed switch units, which must be soldered or otherwise secured into circuit networks.

Another, and perhaps more serious, disadvantage of the prior an arrangement is that in high-frequency applications a lead and one reed contact of the individual switches remain connected to the common terminal even when the switch is open. This introduces unwanted impedances into the circuit at the common terminal resulting in standing waves and impair ment of circuit operating efficiency.

SUMMARY OF THE INVENTION One object of the present invention is to provide a new and improved multiple-contact magnetically operated dry reed switch having a plurality of reed contacts each of which may be selectively operated to engage a single contact common to all the operated reeds.

Another object of the present invention is to provide a new and improved multiple-contact magnetically operated dry reed switching device having a unitary enveloping structure enclosing a plurality of discrete reed contacts cooperating with a single common terminal resulting in a greater degree of compactness and convenience in handling and assembling than prior art arrangements of individual two-contact dry reed switches.

A further object of the present invention is to provide a new and improved multiple-contact magnetically operated dry reed switching device having a unitary enveloping structure enclosing a plurality of discrete reed contacts cooperating with a single common terminal, thus eliminating the need for a like plurality of cooperating reeds, resulting in lower losses and hence improved performance at signal frequencies higher than those using prior art arrangements of individual two-contact dry reed switches.

With these and other objects in view, the multiple-contact switching device contemplated by the invention includes a plurality of movable individual magnetically operated dry reed contacts disposed about a common contact or terminal and packaged within a single protective vessel of glass or other suitable insulating material. The movable reeds are selectively operated by suitable magnetic means to engage or disengage the common contact.

In one illustrative embodiment of the invention a plurality of movable individual radially disposed flexible reeds of electrically conductive magnetic material overlap and are spaced from a centrally located disc of electrically conductive magnetic material common to all the reeds. A glass encasing envelope is provided to receive and support both the reed contacts and the common disc contact. In addition, the envelope is nested within slots formed in sections of a housing which also supports the magnetic facilities for operating the contacts, as well as, electrical components that are selectively connected into outgoing circuits that are energized or completed by operation of the individual reed contacts.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is aperspective view, partly cutaway, of a glasssealed multiple-contact magnetically operated dry reed switch in accordance with the invention;

FIG. 2 is a cross-sectional side elevational view of the contact-operating facilities of a glass-sealed multiple-contact dry reed switch similar to that of FIG. 1;

FIG. 3 is a cross-sectional side elevational view of a variable attenuator utilizing two improved glass-sealed multiple-contact dry reed switches;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3, showing a front view of one of the multiple-contact dry reed switches;

FIG. 5 is similar to FIG. 3 showing the supporting and shielding structure of the variable attenuator with the switchoperating facilities removed;

FIG. 6 is an elevational view of the inside of one of the cover plates of the attenuator-supporting structure taken along the lines 6-6 of FIG. 5;

FIG. 7 is a front elevational view of one of the end plates of the attenuator-supporting structure taken along the lines 7-7 of FIG. 5; and

FIG. 8 is an elevational view of the network housing of the attenuator-supporting structure taken along the lines 8-8 of FIG. 5.

DETAILED DESCRIPTION As illustrated in FIG. 1, a glass-sealed multiple-contact dry reed switching device 10 utilizing the principles of the invention includes a planar array of ferromagnetic reed contacts 11 radially disposed about, spaced from, and in overlapping relationship with a planar disc-shaped metal common contact 12. The reeds I1 and the common contact 12 are supported within a single glass protective envelope comprising a plurality of tubular-shaped radial arms 13 united at their central ends to an extended hub 14. The radial ends of the arms 13 and the extended end of the hub 14 are hermetically sealed around the radial ends of the reeds 11 and a stub conductor 15 soldered or otherwise connected to the common contact 12, respectively, to support the reeds and the common contact within the envelope.

Referring to FIGS. 1 and 2, the switch 10 may be operated to close or open an electrically conductive path between any of the reeds 1 1 and the common contact 12.

A simple contact-operating arrangement for a normally open multiple-contact dry reed switch 10 is illustrated in FIG. 1 wherein permanent magnets 16-16, associated with the individual reed contacts 11, may be selectively moved from an unoperated or rest position magnetically remote from the reed contact to an operated position adjacent to the reed contact. to attract the reed magnetically, flexing it into engagement with the common contact 12 to establish an electrical path therebetween.

In the alternative, the common contact 12 and the reed contacts 1 1 may be arranged so that the switch is operated by flexing the reeds away from the common contact to open a normally closed electrical path therebetween. This latter contact arrangement is shown in FIG. 2 where switch operation is effected by an electromagnet 17 which may be energized to flex a reed contact out of engagement with the common contact 12. The electromagnet 17 associated with each reed contact 11 comprises a core 18 of ferromagnetic material such as soft iron having an operating coil 19 wound therearound. With the electromagnet 17 positioned adjacent to a reed 11 as shown, a current through coil 19 will set up a flux through the magnetic circuit including core 18 and reed 11 thus attracting the free end of the reed toward the electromagnet to open the electrical path between the operated reed 11 and common contact 12. The operated position of a reed 1 1 is represented by phantom lines in FIG. 2. The device thus described may be arranged alternatively for normally open contact operation by substituting the contact arrangement shown in FIG. 1 for that shown in FIG. 2. In such an arrangement the common contact 12 would also be included in the magnetic circuit which operates the reed 11.

The operating means for the multiple-contact dry reed switch heretofore set forth are merely exemplary of the numerous magnetic operating means which may be employed. In particular, an individual operating coil may be wound around each glass radial arm 13 of switch and energized to operate an enclosed reed 11 by producing a magnetic field along the axis of the coil into which the reed would align itself. It will also be recognized that in using the electromagnetic operating means of FIG. 2, it is possible to have a third arrangement of contacts wherein an operated reed 11 could be flexed away from the energized electromagnet 17 into engagement with the common contact 12. This arrangement would include having the common contact 12 of FIG. 2 spaced away from the unoperated reeds 11 and the electromagnet 17. If the airgap between the latter and free ends of reeds 11-11 is large (i.e., the common contact is large compared to the lower pole face of the electromagnet 17 and the reeds 11-11 barely overlap the common contact 12) energization of the electromagnet will cause the free end of its associated reed 11 to flex into engagement with the common contact 12 and in a direction away from the electromagnet 17.

It will also be apparent that the reeds 11-11 themselves need not be made of ferromagnetic material, but may have ferromagnetic material deposited thereon.

It can easily be seen that the unitary structure of each switch 10 affords a much greater degree of compactness and convenience in handling and assembling than would be possible using a plurality of radially arrayed individual dry reed switches. Of particular advantage, however, is that in the above unitary switch structure, the elimination of the reed for an additional reed contact and an associated lead connected to a common terminal for each operable reed, employed in circuits utilizing a plurality of conventional dry reed switches, substantially reduces the occurrence of unwanted standing waves where signal frequencies in the giga Hertz range are utilized. Furthermore, since the electrical path through each operated reed contact 11 on the common contact 12 is substantially shorter than the analogous path in a conventional dry reed switch, the losses within the switch are further reduced.

While the switch structure described utilizes a radial planar arrangement of reeds and a planar disc-shaped common contact, it will be understood that the arrangement of the reed contacts and the shape of the common contact may be modified in numerous ways. In particular, the reeds may be variously arranged around the common contact, e.g., the reed contacts may be supported at an angle to the plane of the common disc-shaped contact. In such cases, the common contact need only be shaped or contoured to engage each operated reed, e.g., the common contact may be shaped as a cone, sphere, or cylinder.

Referring to F108. 3 and 4, there is set forth one embodiment of an apparatus utilizing the principles of the invention including the high-frequency capability of the multiple-contact dry reed switch. A variable or programmable coaxial line attenuator 20 comprises 10 individual fixed passive network attenuators 21 which may be selectively connected between coaxial lines 22-22 through a pair of magnetically operated multiple-contact dry reed switching devices 10-10. The variable attenuator 20 may be used in a coaxial line transmission system as a conventional attenuator for introducing a measured loss into a circuit, or between two mismatched networks as an impedance-matching network. Each fixed attenuator 21 includes a central impedance 23 and two associated depending impedances 24-24, each of which is grounded on one side and electrically connected on the other to the conductive path between one side of the central impedance 23 and the radial end of a reed contact 11. Thus, each fixed attenuator is permanently connected between two reed contacts, one on each switch 10. It follows therefore that the number of reed contacts on each switch 10 corresponds to the number of fixed attenuators 21. The stub conductors 15-15 supporting the common contacts 12-12 of each multiple-contact reed switch are electrically connected to the inner conductors of the coaxial lines 22-22 through suitable coaxial connectors (not shown). All of the electrical conductors interconnecting the components of the attenuators 20 and between the attenuators 20 and the coaxial lines 22-22 are surrounded and supported by right-angular split cylindrical sleeves 25-25 and sleeve sections 26-26, respectively, which may be made of polytetrafluoroethylene or any suitable material having dielectric properties matching those of the material surrounding the inner conductors of the coaxial lines 22-22.

Any combination of fixed attenuator networks 21-21 may be switched between coaxial lines 22-22 by operating two reed contacts, one on each side of a selected network 21. The magnetic operating means for each switch 10 includes a mu]- tilegged ferromagnetic core 27 having a central leg 28 disposed adjacent to the envelope of the multiple contact dry reed switch 10 and aligned with the common contact 12, and a plurality of parallel outer legs 29-29, connected to central leg 28 by core sections 30-30, also disposed adjacent to the envelope and aligned with the reed contacts 1 1. Each parallel outer leg 29 of core 27 has wound therearound an operating coil 31 which, when energized, establishes a flux in the magnetic circuit including the outer leg 29 and the reed contact 1 1 associated with the energized coil and central leg 28. An energizing circuit 32 for opposite pairs of coils 31-31 includes a source of electrical energy (e.g., a battery) connected to source terminals 33, able to be connected to corresponding pairs of coils 31-31 through a plurality of single-pole singlethrow control switches 34-34.

In operation, closing of one or more control switches 34- 34 energizes one or more corresponding pairs of coils 31-31 establishing flux paths in the magnetic circuits associated with each coil 31 flexing the associated reed contacts 11-11 into engagement with the common contacts 12-12, in the same manner as described above in connection with FIGS. 1 and 2 to connect the associated fixed attenuators 21-21 between the coaxial lines 22-22.

Referring now to FIGS. 5, 6, 7 and 8, a generally cylindrical structure for supporting and shielding the components of the variable attenuator of FIG. 3 includes a symmetrical metallic network housing 35 (FIGS. 5 and 8) formed with a plurality of bores 36-36 for receiving and supporting the central impedances 23-23 and part of the split sleeves 25-25, and a like plurality of arcuate guide slots 37-37 on both sides of the housing 35 adapted to receive depending impedances 24-24. The guide slots 37-37 extend centrally inward from the bores 36-36 into communication with a pair of cylindrical recesses 38-38 formed in both sides of the housing 35. The impedances 24-24 are electrically grounded to the inside walls of the recesses 38-38.

The dielectric split sleeves 25-25 extend from the bores 36-36 through a plurality of aligned spaced apertures 39-39 formed in a pair of metallic end plates 40-40 (FIGS. 5 and 7) secured to both sides of the housing 35. Each end plate 40 is formed on one side with a plurality of arcuate short guide slots 41-41 which extend radially outward from a hub 42, and on the other side with a like plurality of arcuate elongated guide slots 43-43 which communicate together at their central ends. The aligned slots 41-41 and 43-43 on both sides of each end plate 40 communicate with each other through a plurality of small bores 44-44 which receive and support the legs 28 and 29-29 of a ferromagnetic core 27. The slots 41- 41 are contoured to fit snugly around depending impedances 24-24 while the slots 43-43 are likewise contoured to receive part of the dielectric split sleeves 25-25 and the radial arms 13-13 of each multiple-contact reed switch 10.

A pair of metallic cover plates 45-45 (FIGS. 5 and 6), secured to both end plates 40-40, are each formed on one side with a plurality of arcuate guide slots 46-46 contoured to accommodate the exposed parts of dielectric split sleeves 25-25 and the radial arms 13-13 of each multiple-contact reed switch 10, and on the other side with an extended sleeve 47 for receiving the central hub 14 of a switch and a dielectric sleeve section 26. The sleeve 47 is adapted to receive a coaxial connector (not shown) associated with each coaxial line 22. The network housing 35, end plates 40-40 and cover plates 45-45 may be secured together by any suitable means such as mechanical clamps or threaded fasteners.

While a variable attenuator arrangement such as shown in FIGS. 3, 4 and 5 might be constructed to utilize conventional twocontact reed switches instead of the two multiplecontact reed switches of the invention, the losses due to the lengths of the reed contacts inherent in such individual reed switches create serious design problems in high-frequency and microwave applications. These losses can be substantially reduced by utilizing the unitary multiple-contact dry reed switching devices.

It is to be understood that the above-described embodiments are simply illustrative of the invention and that many other embodiments may be devised without departing from the scope and spirit of the invention.

What is claimed is:

1. An apparatus for selectively connecting a plurality of electrical networks between two points of electrical potential comprising:

a pair of oppositely disposed multiple-contact switching devices each having a plurality of movable contacts radially disposed about and spaced from a fixed contact;

an insulating envelope encasing each switching device for supporting said contacts;

means for connecting each of said fixed contacts to a point of electrical potential;

contact-actuating means associated with each of said switching devices and adjacent to each envelope for selectively operating the movable contacts of each of said switching devices to engage said fixed contact;

a pair of end plates spaced from each other for supporting said switching devices and said associated contact-actuating means to mutually align the corresponding contacts and associated actuating means of each of said switching devices;

a plurality of electrical networks;

a network housing interposed between said support plates including means for supporting said plurality of electrical networks in spaced parallel relationship between each pair of corresponding mutually aligned movable contacts of said oppositely disposed switching devices;

means for electrically connecting each pair of corresponding mutually aligned movable contacts of said oppositely disposed switching devices through one of said spaced electrical networks; and

means for selectively operating the contact-actuating means associated with the corresponding pairs of mutually aligned movable contacts simultaneously to engage said fixed contacts to connect an electrical network therebetween.

2. An apparatus as set forth in claim 1 wherein:

said contact-actuating means includes an electromagnet including a plurality of parallel outer legs each having an 7 electrical coil wound therearound, disposed about and Parallel to a central leg, said outer legs and said central eg being aligned with and adjacent to said movable contacts, and said fixed contact respectively.

Claims

1. An apparatus for selectively connecting a plurality of electrical networks between two points of electrical potential comprising: a pair of oppositely disposed multiple-contact switching devices each having a plurality of movable contacts radially disposed about and spaced from a fixed contact; an insulating envelope encasing each switching device for supporting said contacts; means for connecting each of said fixed contacts to a point of electrical potential; contact-actuating means associated with each of said switching devices and adjacent to each envelope for selectively operating the movable contacts of each of said switching devices to engage said fixed contact; a pair of end plates spaced from each other for supporting said switching devices and said associated contact-actuating means to mutually align the corresponding contacts and associated actuating means of each of said switching devices; a plurality of electrical networks; a network housing interposed between said support plates including means for supporting said plurality of electrical networks in spaced parallel relationship between each pair of corresponding mutually aligned movable contacts of said oppositely disposed switching devices; means for electrically connecting each pair of corresponding mutually aligned movable contacts of said oppositely disposed switching devices through one of said spaced electrical networks; and means for selectively operating the contact-actuating means associated with the corresponding pairs of mutually aligned movable contacts simultaneously to engage said fixed contacts to connect an electrical network therebetween.

2. An apparatus as set forth in claim 1 wherein: said contact-actuating means includes an electromagnet including a plurality of parallel outer legs each having an electrical coil wound therearound, disposed about and parallel to a central leg, said outer legs and said central leg being aligned with and adjacent to said movable contacts, and said fixed contact respectively.