US3029326A

US3029326A - Resonant reed relay

Info

Publication number: US3029326A
Application number: US848118A
Authority: US
Inventors: Alfred N Fischer
Original assignee: Sargent and Greenleaf Inc
Current assignee: Sargent and Greenleaf Inc; Forum Group Inc
Priority date: 1959-10-22
Filing date: 1959-10-22
Publication date: 1962-04-10
Anticipated expiration: 1979-04-10

Description

April 10, 1962 A. N. FISCHER RESONANT REED RELAY Filed Oct. 22, 1959 FIG. I

l I 15 17 I7 .III

FIG. 5 FIG. 4 INVENTOR,

ALFRED N. FISCHER By M; Abborny 5 United States Patent RESONANT REED RELAY Alfred N. Fischer, Rochester, N.Y., assignor to Sargent & Greenleaf, Inc., Rochester, NY, acorpforation of New York Filed Oct. 22, 1959, Ser. No. 848,118 6 Claims. (Cl. 200--90) The present invention relates to resonant reed relays.

In mobile radio telephone communication apparatus, forexample, a resonant reed relay structure of the type herein may be used to condition an individual receiver for operation in response to a signal of .a distinct frequency. tain a reed of paramagnetic material which has a resonant frequency of vibration in accordance with its physical dimensions. The reed, which serves as one contact in a circuit, is caused to vibrate at its resonant frequency in response to a signal having a frequency correspondingto the resonant frequency of the reed.

The operating characteristics of a resonant reed relay containing a reed of a certain resonant frequency are determined to a large extent by the influence which the permanent magnet, which controls the relay, has on the reed. Anything which effects this magnetic influence will necessarily alter the selectivity characteristics of the structure. reduces the flux-density of the permanent magnet field thus adversely atfecting the operation of the relay. Also, the gradual decay in the strength of the permanent magnet, and subjecting the relay to shock causes it to get out of adjustment which alters its operational characteristics.

Resonant relay structures heretofore known were unable to accurately overcome or compensate for the above external factors. This limited their use, and rendered them unreliable under certain environmental conditions.

In some resonant reed relays heretofore known an adjustable shunt is provided for varying the field of the permanent magnet to adjust the selectivity of the reed structure.

Any resonant relays heretofore known were so constructed, and the individual components of the assemblies were so formed that structures which were designed to operate at lower frequencies, from sixty to five hundred cycles, for example, were unable to be assembled and adjusted for use with resonant reeds having a higher natural frequency, from five hundred cycles to fifteen hundred cycles for example.

One of the objects of the present invention is to provide an improved resonant reed relay structure which overcomes the disadvantages of the previous structures.

Another object of this invention is to provide an improved resonant reed relay structure which permits the accurate calibration of the operational characteristics of the relay with a minimum of final adjustment.

Another object of this invention is to provide an improved resonant reed relay structure which has a permanent magnet field of constant high flux-density.

A further object of this invention is to provide an improved resonant reed relaystructure which permits the rearrangement of parts in the assembly so as to be operable over a wide range of frequencies.

Another object of this invention is to provide an improved resonant reed relay that employs a single piece ceramic magnet for creating magnetic fields of a constant high flux-density.

A further object of this invention is to provide an improved resonant reed relay structure where the casing serves as a return path for the flux of the permanent magnet, thereby serving to further increase the flux-density of the magnet.

For example, an increase in ambient temperature It is well known that these relay structures con- A further object of this invention is to provide an improved resonant reed relay whose operational characteristics may be varied while retaining the same high fluxdensity of the permanent magnet.

A still further object of this invention is to provide a resonant reed relay structure which has a low internal resonance and which has an improved resilient mounting means for isolating the reed structure from its supporting chassis.

A still further object of this invention is to provide an improved resonant reed relay structure which is reliable under all operational conditions, has a long life, is of simple construction, and inexpensive to manufacture.

Other objects of this invention will become apparent from the specification, the drawing, and the appended claims.

In the drawing:

FIG. 1 is a view in elevation with parts broken away showing a resonant reed relay constructed in accordance with one embodiment of this invention;

FIG. 2 is a sectional view showing one arrangement of the components of the assembled resonant reed relay;

FIG. 3 is a sectional view taken on line 33 of FIG. 2;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 2; and

FIG. 5 is a view in perspective showing the configuration of the permanent magnet which is used to control the operating characteristics of the relay.

A. resonant reed relay constructed according to this invention comprises an outer casing which is insulated from and resiliently supports an inner casing. The internal resonance of the structure itself is maintained at a very low natural frequency and the transfer of vibrations from the inner housing to the outer housing is damped or absorbed by placing resilient vibration-absorbing material at each end of the relay. A base having an elongated vibratory reed attached thereto is rigidly supported in the inner casing. A single piece permanent ceramic magnet is adjustably positioned in the inner housing. This magnet has a central opening through which the reed extends or with which the reed is aligned, depending upon the desired operational characteristics of the relay. An electromagnetic coil is positioned in the inner casing surrounding the reed and adjacent the permanent magnet. Both the coil and the permanent magnet maybe positioned in the inner housing at any predetermined distance between the free end of the reed and the base in accordance with the frequency and the operational characteristics desired. Mounted on the reed is i a contact which is positioned to engage a stationary contact that is resiliently mounted on a Wall of the inner casing.

Referring to the drawing, the resonant reed relay structure, generally referred to as 10, comprises an elongated rectangular housing 11 which has an integrally formed closure 12 at one end. A sheet of Mylar insulation 14 lines the walls of the housing 11. Mounted in the housing 11 and positioned adjacent the closed end 12 is a block of resilient material 13 which may be foam rubber. Closing the other end of the housing 11 is a rectangular cap 15 which is attached to and hermetically seals the housing 11. Mounted adjacent the cap 15 in the housing 11 is a block 19 which is made of a resilient material similar to the block 13. A plurality of plug-in terminals 17 extend through the cap 15 and into the block 19. Mounted in the housing 11 and supported between the

resilient blocks

13 and 19 is a rectangular inner casing 21 which is slightly smaller than the outer casing 11 so as to be spaced and insulated therefrom.

A base 25 which is made of a material such as brass is attached in the inner casing 21 and disposed substanspeasae 3 tially flush with one end of the casing 21 to engage the surface of the block 13. A reed 27 is rigidly attached at one end to the base at 28, such as by silver soldering. This reed which in cross-section is of greater width than thickness, may be made of any suitable material, which has a sufiiciently small temperature coefiicient of expansion. As has been previously stated the thickness and length of the reed2'7 determines the natural frequency of vibration. Theretore, by selecting reeds of different dimensions different frequencies can be attained.

Mounted in the inner casing 21 adjacent the base 255 is a spool Cit) made of an insulating material and upon which is wound a coil 32. The spood 3d is substantially rectangular in section and has a substantially rectangular opening. 33 located centrally therein and through which the reedZl' may extend. The spool 39' is cemented to the walls of the inner casing 21.

A. permanent magnet 35, which is of generally rectangular shape in cross-section butwhich has chamfercd corners 36, is positioned in the casing 21 surrounding the reed 27. The magnet 35, which is made of well known ceramic materials, is of single piece construction, and has a central rectangular opening 37.

The surface of the magnet 35 is-in contact with the walls of' the casing 21, and is magnetized so that opposite :walls 3-8 and 39 of the opening 37 of the magnet which are parallel to the wide surfaces of the reed 27 are of opposite polarity.

A mounting block it which may be made of an insulating material, such as phenolic resin, is attached, as by cementing, to the inner casing'21' adjacent the foam rubber block 19. A bracket 42 which is bent to extend in the casing 21 toward the reed 2.7, is attached by rivets 44" to the mounting block 4%. A wire 4-6 is attached by soldering to the bracket 42 and is bent at one end to form a contact '48 and is" connected at its other end to one ofthe terminals 17'. The contact portion 48 is diethe casing 21 to tune the reed 27 sharply to this frequency.

As the flux of a ceramic magnet, such as 35, has a linear temperature coefiicient, and the structure of the relay is such that the permanent magnet 35 may be longitudinally positioned relative to the reed, the operational.

spouse to a low frequency, such as 250 cycles for exposed/adjacent but: normally spaced from a contact protuberance 50 on the reed 27. The contact 48 is adjust able away from or towards the protuberance 59 of the reed 27 in accordance with any desired degree of amplitude of reed vibration by a screw 52 which is-threaded inth'e bracket 42. One end of the screw 52 bearsagainst apiece ofjMylar insulationSdQwhich is cemented to the wall of the inner casing 21. Attached to the Mylar insulation 54 between the wire 46 and the Mylar 54 is a block of" foam rubber 56 which serves to cushion the contact 48 when vibrating. An opening 6t in the inner casing 21 is provided so thatthe screw 52 may be adjusted;

The coil 32 is'conneeted in anelectrical circuit by wires 58"which extend between chambered corners of the magnet"15' and the casing 21 and arev each attached to one terminal 17' to energize the coil -32 in accordance with the frequency of the calling signals. The reed 27 is set in vibrationwhen the coil 32 is energized at the resonant frequency of'thereed 27. Soldered to the wall of the inner casing'21 is a Wire 62 which is connected'to one of theterminals 17. This wire 62 is adapted to be so con nectedin a circuit with the terminal 17, to which the wire 46is connected, that a circuit is closed each time the protuberance 50 makes contact with the contact 48, thus producing a frequency in the outgoing circuit which cor responds to the operating frequency of vibration of the reed: The outgoingclosed circuit in the device includes the reed 27, its base 25 and the inner casing 21.

The/magnet 35, as already stated, is adjustable longitudinally of the'casing 21 to compensate for variations in manufacture and for different desired operating characteristics;

Assuming, for example, that a resonant reed relay constructed: according: to this invention is to operate at six hundred cycles, a reed, which has anatural frequency of vibration corresponding'to thisfrequency, is attached to the: base 25,. and'the permanent magnet is. adjustedv in ample, the permanent magnet 35 is positioned more closely to the base. In the event that the frequency requires the permanent magnet to be positioned so close to the base that the spool 38 is unable to fit between the base 25 and the magnet 35, the electromagnetic coil may be positioned on the opposite side of the permanent magnet between the permanent magnet and the free end of the reed.

Thus, it is apparent that the high flux-density of the one piece ceramic magnet 35 is not decreased for lower frequencies, but that by changing the position of magnet 35 relative to the base 25, the elfectiveness of the flux on the reed can be altered.

Since the ceramic magnet is an insulator, an uninsu lated wire may come in contact with the magnet without impairing the operation of the relay.

Thus, I have provided an improved resonant reed relay which has a reed structure that is resiliently mounted so as to be effective against shock, which has an inner casing that serves as the return path for the flux of'a permanent magnet, in which the magnet may be adjustably positioned for reeds of either low or high frequencies, and which can be reliably adjusted to provide for different desired operational characteristics under different environmental conditions.

While the invention has been described in connection with a specific embodiment thereof, it will be understood e that it is capable of further modification, andthis appli-' cation is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to'which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.

' Having thus described my invention, what I'claim is: l. A resonant reed relay, comprising an outer housing,

one end of which has a plurality of electrically conductive prongs extending therefiom, a resilient mount positioned in each end of said outer housing, at least one of said resilient mounts comprising a block of vibration absorbing material, an inner housing contained within said outer housing and engaging one of said resilient mounts at each end to secure said inner housing'within but spaced from the walls of said outer housing, a permanent magnet having a central bore therethrough, a base secured in said inner housing at one end thereof, a reed rigidly attached at one end to said base and extending longitudinally in said inner housing and in alignment with the bore of said magnet, said magnet being adjustablelongitudinally insaid inner housing to vary the operational characteristics of said relay, an electromagnetic coil positioned in said inner housing-.isurrounding.said reed, said coil being connected to a pair of said prongs for energizing said coilat the natural frequency of vibration of said reed to cause said reed to vibrate, a contact protuberance on said reed, and

adjustable fixed contact positioned in said inner housing and adapted to be engaged by said protuberance during vibration of said reed, a wire connecting said inner housing to another of said prongs, and means connecting said adjustable contact to still another of said prongs for closing a circuit periodically at the frequency of vibration of" said reed.

2. A resonant reed relay according to claim 1 wherein said permanent magnet is made of ceramic material.

3. A resonant reed relay according to claim 1 wherein said bore is rectangular in shape and said reed is made from a flat strip of metal.

4. A resonant reed relay according to claim 1 wherein said permanent magnet isa single piece ceramic magnet and said bore of the magnet is rectangular in shape.

5. A resonant reed relay, comprising an elongated rectangular outer housing, one end of said housing having a plurality of electrically conductive prongs attached thereto, an elongated rectangular inner housing contained within said outer housing, a resilient rectangular block positioned in each end of said outer housing and engaging respective adjacent ends of said inner housing to secure said inner housing within but spaced from the walls of said outer housing, a rectangular base attached in said inner housing at one end thereof, a single piece ceramic magnet, said magnet having a rectangular bore, an elongated reed rigidly attached at one end to said base and extending longitudinally in said inner housing and aligned with said central rectangular bore, said permanent magnet being in engagement with said inner housing and adjustable longitudinally in said inner housing to vary the operational characteristics of said relay, a rectangular spool having a central rectangular opening therethrough, said spool being positioned in said inner housing adjacent the permanent magnet and surrounding said reed, a coil wound on said spool being connected to a pair of said prongs for energizing said coil to cause said reed to vibrate, a protuberance on said reed, a fixed contact positioned in said inner housing and normally spaced from said reed protuberance, a wire connecting said inner housing to another of said prongs, and means connecting said fixed contact to still another of said prongs to close a circuit during vibration of said reed.

6. A resonant reed relay comprising an outer housing closed at both ends, an electrically-conductive inner tubular housing, resilient mounts interposed between each end of said inner housing and the corresponding end of the 7 outer housing, said inner housing being supported from said outer housing on said mounts, at least one of said mounts comprising a block of vibration absorbing material, means insulating said inner housing from said outer housing, a metallic base secured in said inner housing in engagement with said resilient block and closing one end of inner housin an insulating block closing the other end of said inner housing and mounted adjacent the other resilient mount, a vibratory reed, which is of greater width than thickness, secured at one end to said base, an insulating spool positioned in said inner housing to surround said reed and having an electromagnetic coil wound thereon, a bored permanent block magnet also positioned in said inner housing with its bore aligned with the bore of said spool so that said reed may pass through its bore, said magnet having a bore which is rectangular in crosssection and being magnetized so that the two side opposite walls of its bore which are parallel to the wide surfaces of the reed are of opposite polarity, a fixed contact secured to said insulating block in position to be engaged by said reed as it vibrates, means for connecting said reed and fixed contact in an electric circuit when said reed makes contact with said fixed contact, and means for connecting said coil in an electric circuit.

References Cited in the file of this patent UNITED STATES PATENTS 2,758,173 Riley Aug. 7, 1956 2,789,177 Brockway Apr. 16, 1957 2,848,579 Russell Aug. 19, 1958 2,866,028 Russell Dec. 23, 1958 2,894,094 Howell July 7, 1959 2,922,859 Howell Ian. 26, 1960 2,960,585 Russell Nov. 15, 1960