US2422707A - Compressional wave transmitting or receiving device - Google Patents

Description

Jlflne 24, 1947. E E TURNER, JR 2,422,707

COMPEESSIONAL wAvE TRANSMITTING OR `RECEIVING DEVICE l Filed July 29, 1942 .36 Q l a5 4 T A -4o I v 32 42 .a7 .a/ 3o 4/V 35 Q o u u n n u l s n u u y n u s n l e n o d s l c u u l ,514m MV Patented June 24, 1947 y UNITED STATES PATENT oFrxcE COMPRESSIONAL WAVE TRANSMITTING R RECEIVING DEVICE Edwin E. Turner, Jr., West Roxbury, Mass., as-

signor, by mesne assignments, to Submarine Signal Company, Boston, Mass., a corporation of Delaware Application July 29, 1942, Serial No. 452,808 'z claims. (c1. V1v1-ese) 2 The present invention relates to an acoustical the Bakelite" core there are provided flanges transducer of a resonant, or non-resonant type 4D of soft iron which have their cylindrical peoperable at high or low frequencies or over a conripheries recessed to receive coils Il and 42 which siderable frequency range. may be energized by alternating current from the In the present invention two coupled systems 5 leads 44 and 45. are employed, each of which may have differently The magnetic circuit is therefore established 0r similarly tuned resonant characteristics. In through the Alnico central core, the soft iron the present invention the coupling in the device anges and the external magnetic steel tube 30.

is so established that the force factor enhances This sets up radial airgaps at the ends of the magthe adaptability of the device for transmission netic steel tubes on the inside just within the posiof compressional waves through a liquid, preftion of the grooves 32 and 33. Alternating curerablyawater medium. rent flowing through the coils 4I and 42 estab- 1 A furthe;` feature in the present system is that lishes current in the copper aluminum or alloy the electrical energy works at the end of a lontube 31 which provides longitudinal motion or gitudinally vibrating system where the meenamvibration of the copper tube. By making the cal motion is large while the acoustic vibrations copper tube one-half wave length in the material, are derived from latitudlnal vibrations having a alongitudinal resonance will be established. Simreduced vibrational amplitude. In this form of larly, a longitudinal resonance may be estabthe invention the radial vibrations of the longilished in the steel tube 30 but this is made pref-v tudinally vibrating element, preferably the vibraerably to have a resonance for radial vibration. tions near the longitudinal node, are used to pro- Energy is transferred from the vibration of the duce radial vibrations of a tube or shell whose excopper tube to that of the steel tube through the ternal suriace is exposed to the compressional inwardly extending central boss 3l since longiwave-propagating medium. tudinal expansion and contraction of the copper The invention will be more fully described in tube is accompanied by`radial contraction and connection with the specification below when eXDahSiOn at the Center 0f the CODDGI' tube Edtaken in connection with the drawing illustrating jacent the ring or boss member 3 l the same in which Fig. l shows a longitudinal A diagram ofthe operation of the system is in-I section o! one form of the device, Fig. 2 shows a dicated in Fig. 3 in which the tube 31 is indisimilar view of another modification and Fig. 3 30 cated,by the dotted line Li as vibrating in longishows a force diagram of the operation of the tudinal resonance with an expansion and conapparatus. traction in the center section as indicated by theV In the modification shown in Fig. l there is dotted lines T1. This vibration in the central provided an external cylinder whose principal section will be in a direction perpendicular to the form of radiation is radially from the surface of 35 direction of the longitudinal vibrations of the the Cylinder to the sound propagating medium. tube. The transverse vibration is indicated by T This cylinder comprises a magnetic steel tube and the longitudinal vibration by L. When the having an inwardly projecting ring or boss 3l tube 31 contracts in a longitudinal direction, its located midway between the ends of the cylinder. central section expands in the direction of the The cylindrical tube 33 may also be provided with 40 SJITOWS T and thiS eXDaIlSiOn DlOdlCeS an Outward grooves 32 and 33 located at the same distance radial motion of the shell 30, as indicated by the from the ends of the cylinder serving to permit dotted line R1, in the direction of the arrow R.

vibration free from the end effect of the caps on As indicated in Fis. 3 the vibration is maximum the tube. The ends themselves may be made at the center and tapers off to the edges as shown watertight in any usual manner, as, for instance, 45 in the figure. indicated in the figure by the use of a rubber disc The system described in this invention comm 34 which is squeezed outwardly against the inner prises in this respect a double resonant system in walls of the cylinder between two plates 35 and which the two elements are loosely coupled to 3B. Within the cylinder 3B there is positioned a each other and therefore the resonance of one has copper tube 31 which is expanded te fit snug1y 5c only a slight effect on the resonance of the against the projecting ring 3| from the inside of Other and each might be independently tuned in the cylinder. This-copper tube is preferably supmaking the apparatus. In this invention also the ported this way at its midpoint and, in facty the outer steel tube 30 is preferably made heavier whole structure is symmetrical at eithel side of than the inner tube 31 which is made to vibrate the boss or inwardly projecting ring 3i. Within 55 by the induced electrical current from the coil 42. the copper tube 31 there is provided a Bakelite" By properly GhOOSing the IMSS ratio between the core 38 which is supported by a centrally positube 31 and the steel tube 30, it is possible to tioned "Alnico or other high magnetic permeable transform the amplitude of vibration so that a rod I3 which is itself supported by the' end plug large force factor may be available at the water elements as indicated 1n Fig. 1. At each end of so surface and therefore the electrical driving tube,

vmidway between the ends of the tube.

noted that the outer tube l is of non-magnetic material. The magnetic circuit is similar as in the case of the previous modification with a central A1nico" core E and soft iron end flanges l and 8 which, however, are not recessed as in the other iigure. The leads 9 and Ill connect to a coil Il wound around the Bakelite core I2 and this coil provides an alternating iiux for the magnetic circuit which now comprises the Alnico core 6, the end flanges 1 and 8 and the nickel tube 5, the flux running longitudinally in the nickel tube. The'alternating ux applied in this way produces longitudinal vibrations of the nickel tube and these vibrations in the manner which has been described in connection with the other figures produce radial vibrations of the outer vtube i.

The radiation into the water medium is obtained in the present case also preferably by the radial vibrations of the outer cylinder since there is no water load provided on the ends of vibrating tubes so that the energy in the present case is radiated by means of the radial expansion and contraction of the external tubes. If the external tubes are less than one half a wave length long or one-half wave length long, radial vibration will be produced by the tubes with the portions directly over the bearing sections I and 3| having the greatest amplitude of motion and the amplitude at the ends of the tubes adjacent the groove section being substantially less. The construction of the device may further be so made that the tube is tuned for radial vibration rather than for longitudinal vibration. This may be accomplished in the usual well-known manner and will also provide a, coupled system between two coupled resonant structures in which the inner electrically operated member will be vibrated with a free large amplitude.

Having now described my invention, I claim:

1. A compressional wave transmitting or receiving device comprising an elongated hollow cylinder having r. centrally located internally projecting boss, a second cylinder aligned within the first cylinder and supported by said boss, and means for longitudinally vibrating said second cylinder and producing thereby radial vibrations of said first cylinder.

2. A compressional wave transmitting and receiving device comprising an elongated hollow cylinder having a centrally located internal projecting boss, means sealing the ends of the cylinder from the compressional wave-propagating medium, a second cylinder aligned within the ilrst cylinder and supported by said boss, and means for longitudinally vibrating said second cylinder and producing thereby radial vibrations of the first cylinder.

3. A compressional Wave transmitting and receiving device comprising an elongated hollow cylinder having a centrally located internal/projecting boss, means sealing the ends of the cylinder from the compressional wave-propagating medium, a second cylinder aligned within the rst cylinder and supported by said boss, and means for longitudinally vibrating said second cylinder and producing thereby radial vibrations of the first cylinder, said `first cylinder having near its ends deep grooves permitting free radial motion of the portions of the cylinder between said grooves.

4. A compressional wave transmitting or receiving device comprising yan elongated hollow cylinder having a centrally located internally pro-v jecting boss, a second cylinder aligned within the rst cylinder and supported by said boss, means vfor longitudinally vibrating said second cylinder and producing thereby radial vibrations of said rst cylinder, said means including means for establishing a magnetic field in the region at the ends of'the second cylinder, and means inducing a variable electric current in the ends of` said second cylinder for longitudinally vibrating lthe same.

5. A compressional wave transmitting or receiving device comprising an elongated hollow cylinder having a centrally located internallyprojecting boss, a second cylinder aligned within the iirst cylinder and supported by said boss, means for longitudinally vibrating said second cylinder and producing thereby radial vibrations of said rst cylinder, said means including means for establishing a magnetic eld in the region at the ends of the second cylinder, and means inducing a Yvariable electric current in the ends of said second cylinder for longitudinally vibrating,

the same, said second cylinder being tuned longitudinally at the electrical vibrating frequency.

v6. A compressional wave transmitting or receiving device comprising an elongated hollow cylinder having a centrally located internally projecting boss, a second cylinder aligned within the rst cylinder and supported by said boss, means for longitudinally vibrating said second cylinder and producing thereby radial vibrations of said first cylinder, said second cylinder being of magnetostrictive material, and said last means including means vfor producing flux variations in said second cylinder whereby said vibrations are produced.

'7. A compressional wavev transmitting or receiving device comprising an elongated hollow cylinder having a centrally located internally projecting boss, a second cylinder aligned within the first cylinder and supported by said boss, means EDWIN E. TURNER, JR.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,582,590 Fay Apr. 27, 1926 2,064,911 Hayes Dec. 22, 1936 2,249,835 Lakatos July 22, 1941 2,051,866 Kunze Aug. 25, 1936 1,882,393 Pierce Oct. 11, 1932

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