US2638567A - Magnetostriction apparatus - Google Patents

Description

May 12, 1953 E. J. cRoNlN MAGNETosTRIcTIoN APPARATUS Filed May 5, 1950 :FIST-l INVENTOR.

A 7'7'0R/YE Y Patented May 12, 1953 MAGNETOSTRICTION APPARATUS Eugene J. Cronin, San Mateo, Calif.

Application May 5, 1950, Serial No. 160,224

(Cl. S18-118) 3 Claims.

My invention relates broadly to magnetostriction oscillator systems and more particularly to a method of operation and construction of magnetostriction oscillator capable of operation over a relatively wide frequency range.

One of the objects of my invention is to provide a method of operating a magnetostriction oscillator in the ultra-sonic frequency range over a relatively wide range of frequencies.

Another object of my invention is to provide a method of assembling a multiplicity of magnetostrictive elements in a unit capable of sustaining any one of the frequencies individual to the several magentostrictive elements and operative to develop pressure effects incidental to the operation of the individual magnetostrictive elements.

Still another object of my invention is to provide a construction of magnetostriction device which may be connected in an electrical circuit and which is operative to sustain any one of a multiplicity of frequencies by the operation of a tuning circuit which is associated with the device.

Still another object of my invention is to provide a construction of magnetostriction device in which a multiplicity of wires each possessing different rnagnetostrictive frequency characteristics are interralated as la unit and electrically connected in a circuit operative to sustain any one of the individual frequencies characteristic of the multiplicity of magnetostrictive wires.

Still another object of my invention is to provide a construction of magnetostrictive device constituted by an assembly of spheres of differing diameters each possessing individual magnetostrictive frequency characteristics, the assembly being associated with an electrical circuit tunable over a frequency range embracing the frequencies of all of the magnetostrictive spheres whereby the magnetostrictive assembly may be utilized to sustain frequencies over la relatively wide frequency range.

Still another object of my invention is to provide an improved assembly for a multiplicity of magnetostrictive elements, each possessing differing frequency characteristics whereby any one of the individual frequencies of the magnetostrictive elements may be sustained.

A still further object of my invention is to provide an assembly of a multiplicity of magnetostrictive elements capable of generating mag- 5' netostrictive Apressures over relatively wide frequency ranges of the order of 60,000 cycles, and higher.

Other and further objects of my invention reside in novel technique in the manufacture, production and utilization of multiplicity frequency magnetostrictive units as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a schematic view showing the manner of initially assembling the magnetostrictive wires preparatory to the compacting of the magnetostrictive wires into the apparatus unit of my invention; Fig. 2 is a plan view of the assembly of magnetostrictive wires shown in Fig. 1 and illustrating the manner of assembling the wires which possess differing magnetostrictive frequency characteristics; Fig. 3 illustrates the manner of carrying out the molding operation for compacting the magnetostrictive wires as a unit; Fig. 4 is a schematic circuit arrangement of an oscillator system associated with the magnetostriction apparatus of my invention; Fig. 5 is a vertical sectional view taken through a modified form of my invention substantially on line 5--5 of Fig. 6 and illustrating the manner of yassembling a multiplicity of spheres of differing magnetostrictive frequency characteristics in a compact unit; Fig. 6 is a horizontal sectional view through the magnetostriction 'apparatus illustrated in Fig. 5, the view being taken substantially on line `t`6 thereof; Fig. 7 is a schematic view of the magnetostriction apparatus of Figs. 5 and 6, showing the manner of focussing the magnetostrictive pressures; Fig. 8 is a diagrammatic View showing the manner in which an individual spherical magnetostrictive element operates to concentrate the magnetostrictive pressure in a beam; Fig. 9 illustrates the manner in which the magnetostrictive pressure effects may be oriented and focussed with respect to a spherical form of magnetostrictive element; Fig. 10 schematically shows the manner of assembling a multiple number of layers of spherical magnetostrictive elements in a magnetostriction apparatus embodying my invention; and Fig. 11 is a perspective View of one of the commercial forms of the devices of my invention.

My invention is directed to the technique in the art of magnetostriction whereby a unit formed by a composite assembly of a multiplicity of individual magnetostrictive elements may be associated with an electrical circuit responsive to the entire frequency range of the magnetostrictive elements for sustaining oscillations generated at lany one of the frequencies incidental to selected magnetostrictive elements in the composite assembly.

Heretofore in the art the application of magnetostriction techniques has been limited by the i disadvantage that in order to change frequency ated in the same manner described for oil-well p drilling. One important advantage of this technique in mining is that it permits the mining of a vein of ore without removing the surrounding native rock, and other extraneous material, except when necessary to permit passage of the drilling apparatus. This is possible because the materials possessing different physical characteristics have therefore different frequency responses and will not be cavitated in the process. Thus the need for shothole drilling, blasting, mucking, hauling, and milling of tons of valueless earth is largely eliminated.

The drilling of tunnels normally necessitates the use of a special type of mounting equipped with several drilling heads instead of only one. These heads are arranged on a framework so that they may be moved up against the formation to be tunneled as a unit. The procedure for the removal of the cuttings is the same as hereinbefore set forth.

This technique of cavitation at extremely high pressures is applicable to phases of road building, especially resurfacing. .A tractor-type unit having a series of batteries of resonators of the type set forth herein, suspended from a rear platform, proceeds over an old roadbed to be resurfaced, one battery of resonators tuned so that they cavitate the roadbed upon contact, While a second battery of resonators operate on a different frequency and are used to level and compress the pulverized surface back into position by the tremendous pressure developed. Athird battery of resonators on the same frame is connected to the tar or surfacing material distribution system which causes the surface material to be spread onto the road in an atomized condition at considerable pressure. These techniques allow a more complete pulverizing of the roadbed material and compression of the tar or other surf face than has heretofore been attained. With such units it is possible to resurface a road in one operation while driving over it at a slow speed.

Other industrial applications of magnetostrictive ultra-sonic energy devices embodying my invention and operating at selective frequencies will readily suggest themselves, such as laundry and clothes washing equipment Where water is forced under pressure against the textiles to be cleaned.

Referring to the drawings in more detail, reference character I designates a plate of insulation material arranged for the assembly of the devices of my invention during production. The magnetostrictive Wires shown at 2 are cut in relatively short lengths of the order of 11/2 inches. lThe nickel wires are cut to predetermined lengths according to the magnetostrictive frequency characteristics possessed thereby and are set into a mold of insulation material represented at 3. These wires are formed from nickel possessing magnetic properties and they are caused to stand vertically erect on their ends as represented in Fig. 1 by polarization by the bar magnet Il located beneath the plate of insulation material. A plastic insulation material in the fiuid state is poured into the mold 3 around the vertically erect nickel wires 2 and seeps around the wires 2 as represented at 5, and levels off at the top of the mold 3. The wires 2 may be promiscuously arranged Within the mold 3 in generally spiral paths, as represented more particularly in Fig. 2. The pouring operation occurs while the wires 2 are maintained vertically erect in the mold 3 by the polarization due to magnet Il.

The plastic is allowed to solidify forming the unit as represented in Fig. 3 wherein the magnetostrictive Wires 2 have adjacent ends thereof coplanar and their opposite ends of varying lengths terminating in staggered relation within the solidified plastic 5. Fig. 3 shows the completed magnetostrictive unit in inverted position. The opposite ends of the plastic unit extend in spaced planes substantially parallel to each other. The plastic unit thus formed has a minor vertical axis and a major horizontal axis. That is to say the horizontal axis predominates.

In Fig. 4 I have shown the mnner of utilizing the magnetostrictive unit in an oscillator circuit where the unit is encircled by an operating winding 6 which is electrically connected with an ultra-high frequency electron tube oscillator circuit, represented generally at l. The ultra-high frequency oscillator circuit includes electron tube 8 having cathode 8a, control grid 8b and anode 8c. wherein the input and output circuits are coupled through the electrical winding 5 which encircles the magnetostriction unit of my invention. The oscillator circuit 8 includes source of anode potential connected at terminals 9 through radio frequency choke coil l 0 connected to anode 8c. The output circuit of the oscillator includes condenser Il connected between anode 8c and one end of the side of the electrical winding 6. The other end of the electrical Winding 6 connects to grid electrode 8b and an intermediate tap H in electrical winding E connected to cathode 8a. The electrical Winding 6 and the oscillator circuit l are variably tuned by condenser I2 for adjusting the oscillator system selectively over the resonant range of the several magnetostrictive frequencies possessed by the magnetostrictive wires 2. By adjusting condenser I2 the frequency of any one of the magnetostrictive frequency characteristics of the several magnetostrictive elements 2 may be selectively sustained. It is unnecessary to remove a magnetostrictive element of one frequency and substitute a magnetostrictive element of a different frequency as heretofore required in the art.

The magnetostrictive unit as shown in Fig. 4 has the electrical winding 6 thereof hermetically protected by the casing of insulation material M, the opposite ends of which are substantially coplanar with the planes of the opposite ends of the plastic unit 5 which embeds the magnetostrictive wires 2, and because of the fact that the magnetostrictive elements are mounted in plastic 5 these elements are also thoroughly protected within the mold 3. The pressure operating or generating face of the magnetostriction unit is designated at l5.

In Fig. 5 I have illustrated a modified form of my invention in which spheres iii of magnetostrictive material differing from each other in diameter and correspondingly in magnetostrictive characteristics are promiscuously deposited in the mold 3 during the manufacturing process as hereinbefore described in connection with Fig. l, and the liquid plastic flowed around the spheres for embedding the spheres in the plastic. As the spheres become smaller the magnetostrictive frequency becomes higher. The spheres might be made microscopic in size by atomizing molten metal into water or oil. The spheres of different sizes resonate at different magnetostrictive frequencies. Thus a multiplicity of magnetostrictive spheres consolidated into one large unit can embrace a broad band of frequencies, any one of which can be selected when the apparatus is `connectedtin ansoscillator circuitv as shown in-flifig.

'resented fat w18, with ""a'rparabolicelike 41*. eflector back' I9 over Arwhicl1:.=tl1e;magnetostrictive spheres 'Niere promiscuousglyf.distributedvwithin the; plasticl 15. "I'heg;pressure.eiects Egeneratedhy the; several. spheres aregeoncentrated upon 'afocalfpoint 2t :which 'is :located at the 'center of Ian;'arc-icining two-eidesnfthe-encompassing-,coil 6. The balance of thezstructuref shown-lullig "7- is-sixnilar tothe stri-ictures shown zifi-Figs. 5 and' V6.

vliligs. A8 :andi-9 are .'diagra-rnmatical yiews 4ex plaining .the generation.of-;n1agnetostrictivepressure effects 'hy'a magnetostrictive sphere, suchfas .16, and :the emanation-cf such vpressur-e -teiects In zFig. i8 the-electrical AilV i-r1dir 1g 6" is lillustrated surrounding 'the :magnetos-trictive -sphere .l-G which serves: -asa convex- -lensffor directing ymagnetostrictive--energy Aalong the; paths designated atft and -2-5. Anothermovement :of the sphere 1G' to the position shown in Fig. 9:'serves to shift the ',beam of energy emanating 1fromthe -magiziletostrictive sphere |6'teftl'1ev directionsf24 and lIn Fig. l0 Ihave shown the manner-.orarrang-ing a multiplicityv of. layers `of -magnetostrictive :spheres in plastic for securing the'conjoint action thereof. l5-have:y illustrated one layer of l magnetostrictiye l*spheres yat 2|, @an .adjacent layer-fof magnetostrictitve spheres .at '22, and :a further --layer of -v -magnetostrictive f ,spheres at `23. The .several magnetestriotive:spheres may include spheres-of diife-ring-'di-ameters and ,correspondingly ,different magnetostr-ictivefrequency characteristics.

In Fig. 1 1 I: 4have .show-none of .thecommercial embodimentslcof my invention'in the form of .a

circular disc having a thickness sucientf'to inv clude.' a multiplicityfof :em-bedded vmagnetostrictive L spheresfwhichfare vshown Iat A vI 6 ,With Ominute portions ofthesphericalsurfaces thereof extending tangentiallyf-to;af-planertransverseto. the

endfof `,the L-magnetostrictive l unit.

yI Ahave found "-the -magnetostriction:apparatus i of -myainventionweryf eective-.and -eicient :in its operation, :and -While I 'have-described certain' of the embodimentsof i my invention Ifrealize that modifications 4may lbe made and I desire it'to :be be understood .that-no limitations'upon'my invention are intended other thanmay:bef':imposed by thescope' of Vthe appended claims.

8 y-What I .claim as new var,1 cl- .rlesire to secure @by Letters `Patentof theUnited Statesisras follows: .1. Magnetostriction apparatus -scomprising 'a multiplicity of spheres -of .differing-diameters having differing magnetostrictive frequency-characteristics, means for maintaining said-spheres in :compact relation, any electrical Winding 2embracing all ofl said spheres, -an 4oscillator-circuit connected with said electrioa'l'fwinding, andl means for 'tuning' said oscillator circuit over .a lfrequeilcy range embracive of the `magnetostrietive .frequencies of all Vof said spheres ffor selectively sustaining the magnetostrictive'frequencynf any one of the magnetostrictive frequencies of .said spheres generating Apressures incident there to, vthe magnetostrictive pressure effects :generated by said pheres. being focussed at a point disposed inthe center of anarcextendingloetween two sides of the .electrical vWinding embracing said spheres..

2. Magnetostriction apparatus :comprising 'a casing of insulation material open atone :end and'terminating in a circularcurved Wallet uthe oposite end, a multiplicity ofzspheres differing-in diameter and differing in magnetostrictive characteristics one -from another assembled against said curved wall, a plastic filling for said leasing surrounding said spheres and maintaining the assembled position thereof and an electrical Winding surrounding said casing within the magnetostrictive fields .of said spheres.

. 3. Magnetostriction apparatus asset "forth in claim 2 in which said casing has A-a `cylindrical side Wall terminating' in a'flat -p1ane,said plastic filling terminating in a 'ilat plane coincident with the aforesaid plane andsaid electrical'winding-being'iisposed around-the cylindrical side Wall of the casing with the focal point o'f the pressure eifects generated by thel several spheres lying outside the 'flat plane of r'said plastic filling.

EUGENE J. CRONIN.

References Cited in the le of this patent UNITED STATES 4PATENTS Number Name Date 974,024 Carter Oct. 25,:1-.910 1,121,859 ,Messter Dec. 22, 1914 `1,750,124 Pierce `Mar. 11, 1-930 2,116,522 Kunze May 10, 11938 2,328,496 Rocard Aug. 31, 1943 2,398,117 Rost et al Apr. 9, 1946 2,532,876 -Ashe Dec. A5, 1-950 FOREIGN PATENTS Number Country Date 413,762 Great Britain July 26,` 1934

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