US2414699A - Magnetostrictive signal translating apparatus - Google Patents

Magnetostrictive signal translating apparatus Download PDF

Info

Publication number
US2414699A
US2414699A US57070044A US2414699A US 2414699 A US2414699 A US 2414699A US 57070044 A US57070044 A US 57070044A US 2414699 A US2414699 A US 2414699A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
cylinder
microphone
magnetic
signal translating
translating apparatus
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Harry F Olson
Frank A Hester
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B06GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06BMETHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/08Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with magnetostriction

Description

Patented Jan- 21, 194"? FlCE mecnnrosmrorrvn SIIGNAL mansrn'rmo APPARATUS Harry F. Olson, Princeton, N. 3., and Frank A. Hester, New York, N. Y., assignors to Radio Corporation of America, a corporation of Dela- Application December 30, 1944. Seriai No. 5703M with which acoustically responsive devices; such as microphones, are useful. For example, a microphone the output of which is connected to a mine or other explosive charge may be used to detect the presence of a sound emitting target which it is desired to destroy. For this purpose,

it is enerally necessary, to provide a microphone which is mailed in construction and which has good sensitivity.

The primary object of our present invention is to provide an im roved, magnetostriction microphone which will have these characteristics, among others.

More particularly. it is an object of our present invention to provide an improved, magnetostriction microphone which can be used to detect submarine objects with great efficiency. and which will withstand considerable abuse without becoming defective. 1

Another object of our present invention is to prov de an improved magnetrostriction microphone as aforesaid which is particularly useful in connection with mines or other explosive charges.

Still another object of our present invention is to provide an improved magnetostriction microphone ,as set forth above wh ch is very simple in construction and economical in cost.

In accordance with our present invention, the microphone consists of a hollow cylinder of nickel or other ma netostrictive material adapted to vibrate radially under the influence of sound waves impinging thereon. Within the cylinder. we provide a magnetic structure which consists of a laminated core extending diametrically across the cylinder and including a polarizing magnet, the core engaging the interior surface of the cylinder at diametrically opposite points lengthwise thereof. The complete magnetic circuit comprises the polarizing magnet, which may be of laminated Alnico, if desired, the core, which may be of silicon steel laminations, and thecylindrical magnetostrictive tube. plies a polarizing flux through the cylinder. Around the core structure is a signal coil or winding which may be suitably connected to an external amplifier. The hollow cylinder is closed ofi at each end by suitable plates or the like which have fluid-tight relation therewith, the magnetic structure and the coil being housed entirely with- The magnet sup 5 (Cl. 1'l7386) in ,the cylinder. If desired, the microphone may be placed in a suitable baflle.

When sound waves impinge on the cylinder, the peripher thereof is alternately contracted and expanded corresponding to the condensations and rarefactions in the sound waves. This produces a corresponding alternating change of magnetic flux in the magnetic circuit and results in the induction of an ele'ctromotive force in the coil or winding.

The novel features that we consider characteristic of our invention are set forth with particularity in the appended claims. The invention itself. however, both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description of one embodiment thereof, when read in connection with the accompanying drawing in which Figure 1 is a central, longitudinal sectional view, taken on the line I-I of Figure 2, of one form of microphone constructed in. accordance with our present invention,

Figure 2 is a transverse, sectional view thereof taken on the line II-II of Figure 1. and

Figure 3 is a circuit diagram illustrating how our improved microphone may be connected to an amplifying circuit.

Referring more particularly to the drawing, wherein similar reference characters designate corresponding parts throughout, there is shown a normally open-ended cylinder i of nickel or other, suitable magnetostrictive material to the ends of which are secured, by brazing or the like, a pair of rings 3. A pair of end plates 5 are secured to the rings 3 in fluid-tight relation thereto, thus closing off the interior of the cylinder I from the ambient or surrounding medium.

Within the cylinder I and extending diametrically, thereacross is a magnetic field structure comprising a plurality of oppositely disposed, substantially T-shaped laminations I and one or more permanent magnets 9. The laminations i may be formed of silicon steel, and the magnets 9, which supply a polarizing flux through the laminations i and the cylinder i, may be of Alnico, and preferably also of laminated construction. The laminations i may be stepped, as clearly shown in Figure 2, and are tightly clamped together, the longest ones being disposed in the center and substantially in the plane of the axis of the cylinder. The laminations i are arranged in two oppositely disposed groups, one or more of the longest ones of each group in a radial direction through the cylinder being so arranged that which is open at the top, the magnetostrictive cylinder I having an external diameter which is smaller than the internal diameter of the baffle.

I5 and being arranged concentrically therewith to provide an annular space. I! therebetween.

The output leads from the coil It may be brought out in the form of a cable l9 through a fluid-tight coupling 2| of any suitable construction.-

When sound waves strike the vibratory cylinder I, it vibrates radially by alternately contra'cting and expanding somewhat in correspondence with the condensations and rarefactions in the sound wave. The alternating change of magnetic flux which results in the magnetic circuit induces an electromotive force in the coil lithe output of which may be applied to an amplifier 23 or any suitable type. A microphone constructed as above has an impedance which is highly reactive. Its impedance can be reduced to the resistive component by inserting a capacitance 25 in series with the coil iii. The microphone of our present "invention is a relatively low impedance device, having a resistance of approximately ohms" at 350 cycles per second. A coupling transformer 21 may therefore be used to couple the microphone to the amplifier 23 to step up to 250,000 ohms. This confines all high impedances to the vacuum tube amplifier.

The transformer may be tuned where band pass response, is desire'd,

A microphone such as described above will be. found to be extremely rugged, as evidenced by the fact that it can be struck a relatively hard blow with a hammer and dented without appre-. ciably impairing its response. In view of the low impedance of the microphone, moisture will, not impair its performance. It will be found that a microphone of this type can be made very sensitive, and its low frequency response can be increased considerably by the addition of the baflle l5.

Although we have shown and described but a single embodiment of our present invention, it will undoubtedly be apparent to those skilled in the art that many other modifications, as well as variations in the one described herein, are possible within the scope of our invention. It will also be apparent, no doubt, that our present invention can be employed as a sound transmitter or projector, instead of as a microphone or receiver, by passing signal currents through the coil l3 which, in turn, will vary the flux in the magnetic circuit and thereby cause the cylinder l to vibrate and radiate sonic waves. Since the present ind nation of a hollow cylinder of magnetostrictive material adapted to vibrate:radially, magnetic means within sa id cylinder extending diametrically thereacross and providing a magnetic path between diametrically opposite points on said other in the region of the axis of said cylinder,

and characterized further in that said polarizing magnet comprises a permanent magnet disposed in the space between said laminations in engagement with the adjacent ends of said opposed laminations. h

3. Signal translating apparatusaccording vto claim 1 characterized in that said lamlnations, comprise substantially T-siiaped member (1) the cross arms of which are arranged lengthwise of said cylinder and are in engagement with said cylinder at said diametrically opposite points and (2) the legs of which extend radially across said cylinder toward each other in opposed relation from their respective cross arms, said legs said cylinder in fluid-tight relation thereto and closing off the interior of said cylinder from the ambient, magnetic means within said cylinder extending diametrically thereacross and providing a magnetic path between diametrically opposite points on said cylinder, said magnetic means including a polarizing magnet. a winding also within said cylinder disposed around said magnetic means, and a'bai'ile surrounding said cylinder,

said baiile having a longer cross sectional dimension than the external diameter of said cylinder whereby to provide a space between said cylin-' der and said baille.

5. In signal translating apparatus, the combination of a normally open-ended. hollow cylinder of magnetostrictive material adapted to vibrate radially, closure means secured to each end of said cylinder in fluid-tight relation thereto and closing oi! the interior of said cylinder from the ambient.'magnetic means within said cylinder extending diametrically thereacrossand providing a magnetic path between diametrically opposite points on said cylinder, said means including a polarizing magnet, a winding also within said cylinder disposed around said magnetic means, and a cylindrical bame around said cylinder in concentric relation thereto. said baiiie having a longer internal diameter than the ex- I ternal diameter of said cylinder whereby to provide an annular space therebetween.

HARRY F. OLSON. FRANK A. HESTER.

US2414699A 1944-12-30 1944-12-30 Magnetostrictive signal translating apparatus Expired - Lifetime US2414699A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US2414699A US2414699A (en) 1944-12-30 1944-12-30 Magnetostrictive signal translating apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2414699A US2414699A (en) 1944-12-30 1944-12-30 Magnetostrictive signal translating apparatus

Publications (1)

Publication Number Publication Date
US2414699A true US2414699A (en) 1947-01-21

Family

ID=24280700

Family Applications (1)

Application Number Title Priority Date Filing Date
US2414699A Expired - Lifetime US2414699A (en) 1944-12-30 1944-12-30 Magnetostrictive signal translating apparatus

Country Status (1)

Country Link
US (1) US2414699A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2607833A (en) * 1947-12-18 1952-08-19 Stromberg Carlson Co Telephone ringer
US3160769A (en) * 1961-09-26 1964-12-08 Frank R Abbott Magnetostrictive transducer
US5980251A (en) * 1997-08-05 1999-11-09 Coltene/Whaledent, Inc. Laminated magnetostrictive transducer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2607833A (en) * 1947-12-18 1952-08-19 Stromberg Carlson Co Telephone ringer
US3160769A (en) * 1961-09-26 1964-12-08 Frank R Abbott Magnetostrictive transducer
US5980251A (en) * 1997-08-05 1999-11-09 Coltene/Whaledent, Inc. Laminated magnetostrictive transducer

Similar Documents

Publication Publication Date Title
US3665124A (en) Loudspeaker having annular diaphragm with double voice coil
US3649776A (en) Omnidirectional horn loudspeaker
US3592967A (en) Ultrasonic detector
US3068446A (en) Tubular electrostrictive transducer with spaced electrodes and loading masses
US3129347A (en) Magneto-electric motion detecting transducer
US4472605A (en) Electrodynamic loudspeaker for low and medium sound frequencies
US3439128A (en) Miniature ceramic microphone
US1167366A (en) Dynamo-electric machinery.
US6175637B1 (en) Acoustic transducer
Olson Electronic control of noise, vibration, and reverberation
US2348225A (en) Magnetic seismometer
US3256738A (en) Magnetostrictive transducer
US4609784A (en) Loudspeaker with motional feedback
US5197104A (en) Electrodynamic loudspeaker with electromagnetic impedance sensor coil
US2552878A (en) Second order differential microphone
US4720868A (en) Dynamic transducer device
US2225312A (en) Acoustic device
US2683856A (en) Magnetic-electric transducer
US3018467A (en) Resonant reactively operating variable position transducer
US2076330A (en) Measurement of distances by echo reception methods
US3911388A (en) Accelerometer
US5214710A (en) Permanent magnet system with associated coil arrangement
US4010334A (en) Moving magnet contact acoustic transducer
US2416557A (en) Electroacoustic transducer
US2429104A (en) Signal translating apparatus