US3145312A - High frequency sonic transducers - Google Patents

Description

13, 1964 J. w. MCAULEY HIGH FREQUENCY SONIC TRANSDUCERS Filed April 13, 1959 QIVENCTOR. BY 900120]. flGMfJWG Qe ATTORNEYS Fig.8

3,145,312 Patented Aug. 18, 1964 3,145,312 HIGH FREQUENCY SONlC TRANSDUtIERS James W. McAuley, Toledo, ()hio, assignor to Libby- Owens-Ford Glass Company, Toledo, Ohio, :1 corporation of Ohio Fiied Apr. 13, 1359, Ser. No. 806,152 7 Claims. (Cl. 310-26) The present invention relates broadly to high frequency sound generating transducers and more particularly to improvements in the energy directing means forming a part of said transducers as employed in treating surfaces.

For example, the cleaning and surfacing of glass sheets has been accomplished by the utilization of high frequency sound energy. Thus, in a cleaning operation the surface of a glass sheet to be cleaned is covered with a liquid conducting medium consisting of water, or water plus an additive, and sonic energy is applied to the medium to cause cavitation therein which results in a thorough cleaning of the glass. For surfacing, the conducting medium is provided with an abrasive material which on cavitation in the medium is caused to bombard the glass surface and to remove portions thereof.

Sound energy generating apparatus for accomplishing such cleaning and surfacing operations must produce relatively high power level outputs, which darnands that transducers for providing the energy have a relatively high efliciency and be of a rugged construction. Other features that are required in such transducers are that they can be replaced individually, that they can be maintained in any preferred orientation without a substantial diminution of operating efficiency or power output level, that they be reasonably inexpensive, and that they be easily adaptable for effective use within a relatively wide band of frequencies of excitation voltage.

Perhaps the best sound generating transducers for glass cleaning and surfacing operations are magnetostrictive transducers provided with a metallic energy directive means firmly attached to the magnetostrictive element or core.

Originally such energy directive means were solid bodies of metal, dimensioned to be mechanically resonant at the operating frequency of the transducer.

' However, it was soon found that in order to be satisfactory for their intended purpose such solid bodies had to be formed,'machined or otherwise shaped in a particular way and, as so shaped, came to be commonly known as horns. But, even with this special shaping, the solid horn was not fully effective for underwater applications such as the surface treating uses described above.

Subsequently, in United States Patent No. 2,723,386, issued November 8, 1955, to Leon W. Camp, it was proposed to use a plurality of small legs, extending in parallel relation from the electro mechanical vibrator and connected at their outer ends to a unitary diaphragm, as the horn or energy directive means.

In this arrangement, however, each of the individual legs making up the horn had to be specially and accurately shaped so that, while improved results were obtained, the cost of producing the horns was even higher than before.

Still later a so-called hollow horn was proposed as a means of increasing the effectiveness of such transducers. Again, while this modified construction gave somewhat improved results it still further increased the already almost prohibitive cost of the horns because it added new problems in the way of shaping and accurate machining and it was still considered necessary to provide such hollow horns with legs, in the form of reinforced wall portions extending in the direction of vibratory energy transfer, as a means of suppressing spurious lateral vibrations that might damage the directive means and/ or change the natural frequency of the transducer with a resultant lowering of optional efficiency.

Further, it was thought heretofore that all of these specially shaped, energy directive means had to be constructed of a relatively expensive, high corrosion-resistant, diflicult to machine stainless steel. The casting and machining of such energy directive means is a considerable portion of the total labor cost of a transducer and, as indicated above, prior to the present invention, the production of such energy directing means was extremely time-consuming and approached the prohibitive in cost.

This invention is based on applicants discovery of a novel type of hollow, vibratory energy directing member for use with sound generating transducers that is readily obtainable, that can be constructed of relatively inexpensive and easy to work materials, and that requires no special subsequent shaping procedure.

Briefly stated, the horn of the present invention is of multipiece construction embodying a cylindrical or tubular extension member that will give results that are equal, if not superior, to the results obtained with the complicatedly shaped difficult to produce prior known structures.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

FIG. 1 is a perspective view, partially in section, of the complete novel vibration directing means of the invention assembled into a magnetostrictive sonic energy generating transducer device; and

FIG. 2 is an exploded perspective view of the energy directing means of FIG. 1.

With reference now to the drawings and particularly to FIG. 1 there is shown a high frequency sound generating transducer of the type with which the present invention is particularly concerned. This transducer comprises a core 10, an energizing coil 11 in surrounding relationship to said core, and a special energy directive means 12 mounted in fixed contacting relationship with a vibrating portion of the core.

As shown, the core ltl consists of a plurality of U- shaped laminations of a magnetostrictive material such as nickel placed in a face contacting relationship forming a unitary structure. It is essential that the laminations be maintained in this close contacting relationship in order to provide a stable operation, which may be accomplished either by a mechanical means such as the clip 13 or by bonding the core lamination together in a plastic or resinous material.

The coil 11 consists of a plurality of turns of wire inductively wound on the two legs of the core. Additionally, a polarizing means is usually provided which can be, for example, either a second coil wound on the core for passing a direct current therethrough or, as shown in FIG. 1, a permanent magnet 14 located between the two legs of the core. Energization of the coil 11 with a suitable high frequency voltage source (not shown) causes a cyclic increase or decrease in the length of the legs of the core 10 which provides a source of vibratory energy, or vibrating surface, at the lower or cross bar portion of the core. The directing and amplifying means 12 in a completed unit is affixed to this lower vibrating surface of the core by silver soldering, brazing, welding or other similar means.

Although for puropses of illustration the core 10 is shown to be composed of laminated sheets of ferromagnetic material it is considered that the novel directive means of the invention would be equally applicable for use with a sound generating core composed of a magnetostrictive ceramic, a piezoelectric crystal, or any other conventionaltype of vibratory energy source.

The novel vibratory energy directive means 12 of the invention comprises three main parts, namely, an upper portion 15, a central extension member 16, and a lower energy distributing portion or operating member 17. These three individual units are integrally combined in a way which will be set forth below to form a superior sonic energy directive and amplifying device the purpose of which is to transfer and amplify the vibratory energy generated by the core to a point where it can be used to perform useful work.

In a preferred construction, the upper portion 15 consists of a cast metal base member having a circular flat face 18 which in the completed transducer is Welded or otherwise fixedly secured to the lower surface of the cross arm of the core 10. There is also provided a cylindrical plug 19, integral with the body member and having a diameter less than that of the face 18, that extends in a direction substantially 90 to the flat face of the body member. The plug 19 may be either solid or partially hollowed out so as to enlarge the central cavity within the completed directing means as shown in FIGS. 1 and 2. Although it is well known that the provision of a cavity within a vibratory energy directive means produces an amplification of the vibratory energy, the use of a solid plug rather than a hollowed out one does not cause a diminution of the total amplifying effect afforded by the cavity, of'such a magnitude as to preclude its use. It is, therefore, considered within the contemplation of the invention to use an upper portion 15 having a plug 19 consisting either of a solid or hollowed out cylinder.

The upper portion 15 is also provided with a first cylindrical portion 20 concentric with the plug 19 and having a diameter slightly larger than the plug, and a second cylindrical portion 21 concentric with and having a diameter slightly larger than the portion 20. The purpose of these cylindrical portions will be brought out in detail below.

The extension member or horn 16 comprises essentially an elongated cylindrical metal tube the ends of which are finished off in planes perpendicular to the long dimension of the member. The inner diameter of the member is of such a dimension as to permit it to receive the plug 19 therein in a closely fitting relationship.

Contrary to conventional opinion which is that the energy directive member must be made entirely of stainless steel applicant has found that the extension member 16 may be made of any of a large number of different metals having reasonable strength and resistance. For example, metals which have been found to be fully satisfactory in this regard are aluminum, copper, bronze, and brass.

The lower portion 17 preferably consists of a metallic base portion having a flat substantially rectangular surface 22 tapering to a short cylindrical portion 23 rising from the rectangular surface in a normal direction and having an opening therein of sufficient diameter to allow it to receive the extension member in a tightly fitting manner. Although the energy distributing portion may be composed of the same metals listed above with regard to the extension member 16, the flat working surface 22 may be provided with a hard metal wearplate (not shown) firmly attached thereto and completely covering the rectangular face portion.

The different parts of the multipiece energy directive means 12 can be joined to one another by brazing, silversoldering or welding, but it is the concept of the invention that an organic epoxy resin cement, such as Epon 6 or 8, is preferable. Not only is the use of such an adhesive material relatively inexpensive and easier to apply than the above-mentioned alternative methods, but the completed unit can be disassembled easily without damaging the different component parts. Thus, if it is desired to take the directive means 12 apart this may be done by placing the unit in a furnace and subjecting it to a temperature of aproximately 300 F. for several minutes which will cause the organic cement holding the parts together to disintegrate releasing them while leaving the individual parts of the transducer undamaged.

It is to be noted that when the upper portion 15 is assembled to the extension member 16 the shoulder of the cylindrical portion 20 rests on the upper end of member 16, and that the peripheral surface of the portion 20 is recessed below the outer surface of the member 16. When the completed transducer is mounted for operation a sealing gasket, such as an O-ring, is received in this recess and forced against the shoulder of cylindrical portion 21 to provide a liquid-proof seal preventing the access of the energy conducting liquid to the electrical part of the transducer. 7

The novel construction of the energy directive means set forth herein has several important advantages over the' conventional known structures of the same general type.

Thus, as was brought out above, whereas it was previously considered necessary to construct an energy directing member with specially reinforced portions, or legs, the directive member of the invention has eliminated the legs and in so doing has overcome the problem of diflicult forming techniques and the need for difficult and expensive machining afterward.

Also, as was noted before, it was previously thought to be necessary to construct the complete directive members of relatively expensive high corrosion-resistant stainless steels which are diflicult to cast and machine. However, it has been found in the special multipiece construction of this invention that the central extension member 16 and the lower member 17 can be made from certain relatively inexpensive easily obtainable metals rather than stainless steels.

A further advantage to be obtained by the novel construction of the invention is that it possesses a flexibility that permits the production of units which may be quickly and easily adapted to use with excitation voltages over a relatively wide range of frequencies. By way of explanation, vibratory energy directing members must have a precise overall length. That is, a precise dimension measured along the line of vibratory energy transmission, which dimension is directly dependent upon and determined by the frequency of the excitation voltage of the transducer. It has been found that even a slight variation in this dimension from the optimum results in a sharp drop in performance. The prior art structures discussed above were constructed for a particular voltage frequency and could be varied only a very slight amount by machining one end so as to reduce the length. However, in the directive member of the invention the lower iember' 17 and the upper portion 15 that is secured to the core may be combined with central extension members of various lengths to provide completed transducers for use with a variety of different excitation voltage frequencies. Summing this up in different Words, Whereas in the prior art each transducer was made for use with a particular voltage frequency, the invention makes it possible to provide transducers for use with a relatively wide band of input voltage frequencies by merely cutting the cylindrical extension members to predetermined lengths and asembling them with the same lower members and upper portions.

A still further advantage of the invention is that which results from the use of a non-metallic adhesive material to join the individual parts to form the completed directive member rather than brazing or welding them together. With such a construction if the operating face 22 becomes worn or damaged the lower member 17 can be removed relatively easily and a new one cemented in place. This of course, would not be possible with the prior devices discussed above since their Welded unitary construction does not permit such partihl replacement and instead requires that the whole device, frequently including the laminated core and coil, be discarded in case of damage to any part thereof. On the other hand, with this invention both the extension member and the lower member may be removed and new ones substituted without the laminated core or the coil windings being injured.

It is to be understood that the forms of the invention disclosed herein are to be taken as the preferred embodiment thereof, and that various changes in the shape, size and arrangement of parts may be resorted to Without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. A sound energy directing and amplifying means for use in a magnetostrictive sound generating transducer, comprising a metallic body member for attachment to a vibrating magnetrostrictive body and having a plug-like portion integral with said body member extending therefrom, a hollow cylindrical extension member having an opening therein for receiving the plug portion of the contacting member in one end thereof, a second body member provided with a circular opening for receiving the other end of the extension member therein and having an outer substantially fiat operating face normal to the long dimension of said extension member, and adhesive bodies securing said metallic body member to said extension member and said extension member to said second body member.

2. An energy directing and amplifying means as claimed in claim 1, wherein said extension member and said operating portion are composed of a non-ferrous metal.

3. An energy directing and amplifying means as claimed in claim 1, wherein said adhesive bodies are composed of epoxy resins.

4. A high frequency sonic transducer, comprising a laminated core of magnetostrictive metal, a coil for energizing said core, a metallic body member welded to said core, having a cylindrical plug portion extending therefrom along the line of major magnetostrictive movement, a hollow metallic cylinder having the planes of its ends normal to the center line of the cylinder the internal opening of which is so dimensioned as to receive the end of the cylindrical plug therein in a tight fitting relationship, a second body member having an opening therein for receiving the other end of the extension member therein, and non-metallic adhesive means for securing the cylinder to the cylindrical plug and also to the second body member in a tightly sealed unitary relationship.

5. A sound energy transducer, comprising a hollow cylindrical metal tubular member of substantially uniform diameter throughout its length and open at its opposite ends, a first metallic body member having a flat outer face and a plug-like portion fitting within and closing one end of said tubular member, a second metallic body member having an opening for receiving the other end of the tubular member therein and provided with an outwardly directed flat operating face closing the adjacent end of the tubular member, means for detachably securing the first and second body members to the tubular member, and a vibration generating core rigidly secured to the outer face of the first body member.

6. A sound energy transducer as claimed in claim 5, in which the means for detachably securing the first and second body members to opposite ends of said tubular member comprises a heat softenable resinous adhesive.

7. A sound energy transducer, comprising an elongated tubular metal member having a cylindrical wall of substantially uniform diameter throughout its length, said cylindrical Wall defining a cylindrical passageway of substantially uniform diameter throughout the length thereof and open at its opposite ends, a first metalliic body member having a fiat outer face and a plug-like portion projecting into said passageway and closing one end thereof, a second metallic body member having an opening for receiving the other end of said tubular member and provided with an outwardly directed flat operating face closing the adjacent end of said tubular member, means for detachably securing the first and second body members to said tubular member, and a vibration generating core rigidly secured to the face of said first body member.

References Cited in the file of this patent UNITED STATES PATENTS 1,380,869 Fay June 7, 1921 2,498,990 Fryklund Feb. 28, 1950 2,748,298 Dalosi May 29, 1956 2,779,695 Brown Jan. 29, 1957 2,930,913 Camp et a1 Mar. 29, 1960 2,946,981 ONeill July 26, 1960 2,956,789 Rich Oct. 18, 1960

Claims (1)

1. A SOUND ENERGY DIRECTING AND AMPLIFYING MEANS FOR USE IN A MAGNETOSTRICTIVE SOUND GENERATING TRANSDUCER, COMPRISING A METALLIC BODY MEMBER FOR ATTACHMENT TO A VIBRATING MAGNETROSTRICTIVE BODY AND HAVING A PLUG-LIKE PORTION INTEGRAL WITH SAID BODY MEMBER EXTENDING THEREFROM, A HOLLOW CYLINDRICAL EXTENSION MEMBER HAVING AN OPENING THEREIN FOR RECEIVING THE PLUG PORTION OF THE CONTACTING MEMBER IN ONE END THEREOF, A SECOND BODY MEMBER PROVIDED WITH A CIRCULAR OPENING FOR RECEIVING THE OTHER END OF THE EXTENSION MEMBER THEREIN AND HAVING AN OUTER SUBSTANTIALLY FLAT OPERATING FACE NORMAL TO THE LONG DIMENSION OF SAID EXTENSION MEMBER, AND ADHESIVE BODIES SECURING SAID METALLIC BODY MEMBER TO SAID EXTENSION MEMBER AND SAID EXTENSION MEMBER TO SAID SECOND BODY MEMBER.

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