US2799071A - Magneto-striction device for casting - Google Patents

Description

July 16, 1957 R. E. SCHENK MAGNETO-STRICTION DEVICE FOR QASTING Filed March 21, 1955 I N V EN TOR: flpfiaff ATTORNEYS.

United States PatentC" MAGNETO-STRICTION DEVICE FOR CASTING Robert E. Schenk, Waterloo, Iowa Application March 21, 1955, Serial No. 495,402 6 Claims. (Cl. -41) This invention relates generally to vibrating means employed during casting operations for agitating the material being cast, and more particularly to a magneto-striction device mounted in novel cooperative relation wtih casting forms for eifecting vibratory casting.

The use of vibrational energy for agitating casting molds or forms to improve the density packing and particle. distribution of the material being cast, and the application of magneto-striction as a source of vibrational energy in such casting operations have been previously known. The devices which have been employed by the prior. art have imparted vibrational energy to the material being cast in one of two ways. In some arrangements, a vibrating plate or element is directly immersed in the material being cast and imparts vibrations directly to the surrounding material. In other arrangements, alternating electrical energy elfects movement or vibration of an entire mold unit relative to complementary mold unit, thereby vibrating and compacting the moldable, material enclosed between the mold units. In still other arrangements, mechanical energy in the form of repeated hammer blows is imparted to a mold form.

In the casting of metals, concrete, and other materials having either pulverulent, granular, or fluid physical characteristics, it is highly desirable to provide a simple,

compact, and efficient means for imparting vibrational energy to a wide variety of molds and forms which encloserelatively large volumes of material, and which frequently provide a geometry of compound curves and bends, Without the necessity for specialized equipment having inflexibly matched vibrator and mold design.

It is a primary object of this invention, therefore, to provide a magneto-strictive vibrator unit which is adapted to be particularly mounted in a novel manner relative to a casting form'serving as a vibrating diaphragm, whereby vibrational energy may be imparted over a large surface area of compound contour with high efliciency.

It is another object of this invention to provide a magneto-strictive vibrator unit having rigid support means adapted to be fixedly secured to the surface of a casting form serving as a vibrating diaphragm, wherein a magneto-strictive rod is rigidly attached to said support means and to the surface of the form for transmitting vibration thereto when energized. It is a further object of this invention to provide a mold assembly for vibratory casting, wherein magnetostrictive vibrational energy is imparted by a vibrating diaphragm through a fluid medium to a casting form.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my magneto-striction device for casting whereby theobjects contemplated are obtained as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing wherein:

Figure 1 is a perspective view of an arrangement of casting forms having the magneto-strictive device of the 2,799,071 Patented July 16, 1957 present invention mounted in operative relation therewith;

Figures 2, 3 and 4 are plan, end, and side elevational views, respectively, of the magneto-strictive vibrator unit shown in Figure 1;

Figure 5 is a cross-sectional view showing a modified manner of mounting the magneto-strictive vibrator for cooperation with the casting forms; and

Figure 6 is a diagrammatic sketch showing the electrical field induced by the coil of the magneto-strictive vibratorassembly for effective vibratory movement of the rod thereof.

Referring now more particularly to Figures 1 through 4 of the drawing I have shown a magneto-strictive vibrator assembly 10 fixedly mounted in a particular manner against the outer wall surface of 'an external casting form. For purposes of illustration, the form 12 is shown as being generally cylindrical, but it will be understood that the form may have compound contours and bends. An internal casting form 14 of complementary shape is disposed within the external form 12 in spaced relation thereto for defining therebetween the volume and form of the casting to be produced.

The vibrator assembly 10 comprises a housing 16 ha ing a pair of rigid support arms 18 and 20 extending outwardly therefrom for fixedly mounting the housing 16 to the form 12 by means of a rigid frame 22.- The frame 22 is shown as having straight sides 24 and curved sides 26 conforming to the arcuate form of the form 12. It will be understood that a separate vibrator panel may be carriedby the frame 22 as a distinct element providing. a complementary surface contiguous with surrounding surfac s of adjacent panels adapted to be mated therewith in rigidly interfitting engagement to define a form assembly equivalent to the unitary form 12. It is of essential importance that the support arms 18 and 20 be suitably secured in a rigid manner directly to the form 12 onto an integral surface portion thereof.

An electrical coil 28 of annular form is carried within the housing 16, and is fixedly held therein by means of a filler plug. The coil 28 provides a central opening through which an elongated vibrator rod 30 extends longitudinally. The'rod 30 terminates inwardly in a head portion 32, and is fixedly secured outwardly to the housing 16 by means of a closure cap 34. The coil 28 is removable from the housing 16, and is intended to be interchangeable with other coils for providing various vibrating frequencies, as desired.

When the coil 28 is energized by an alternating current, a cyclically intermittent magnetic field is induced about, the rod 30. This field is indicated diagrammatically in Figure 6, and will be induced instantaneously at a peak in the electrical current cycle. In this way, it is possible to effect a shortening of the length of the rod 30 by means ofthe force exerted by the magnetic attraction of the induced north and south pol-es at the opposite rod ends. When the field decays, the normal inertia and elasticity of the rod causes it to spring back to its normal length. For. this purpose of alternate shortening and lengthening, the rod 30 is of suitable magnetostrictive material, such as nickel or annealed cobalt. Although the magnitude of this action of rod movement is very small, it is suflicient to effect a rapid vibration of rod head portion 32 relative to the housing 16.

The rod head 32 is rigidy attached to the surface of the form 12. In this way vibrational energy of the energized rod 30 will be imparted directly to the surface of the form 12 causing the form to be vibrated in the manner of a diaphragm in a controlled frequency as regulated by the energized vibrator rod 30. It is an essential feature of the present invention that both the housing 16' (by means of arms 18 and 20), and the free end of rod 30 (by means of head 32), be fixedly secured to the form 12.

Preferably, the vibrated form 12 is of a suitable metal which is as diamagnetic as possible, while retaining adequate strength and resilience. Where the apparatus is employed for the casting of materials at high temperatures, adequate heat resistance is also a necessary characteristic of the vibrated form. The stiffness of the rigid frame 26 must be greater than the stiffness of the vibrated form 12. The rigid connections between the virator rod 3%), and the support arms 18 and 20, with the vibrated form 12 may be accomplished in any suitable manner, as by welding, pins, or screw-threaded couplings.

In Figure 5 of the drawing, I have shown a modified arrangement in which the vibrations from a coil unit 4'1 having rigid suport arms 4-2 and 44 rigidly secured to a vibrator diaphragm or panel 46 by means of a rigid mounting frame 48, are transmitted through a fluid medium 58 to the face of an outer form 54. An inner form 56 cooperates with the outer form 54 to define the casting volume and enclose the casting material 60. In this way, vibrational energy is transmitted by the vibrator diaphragm 46 through the fluid medium 58 to the outer form 54 which serves as a second or inner vibrator diaphragm. The intermediate fluid 58 further serves to balance and distribute the vibrating energy passing from diaphragm it? to form 54, resulting in a more uniform agitation and distribution of the material 60 being cast between the forms 54 and 56.

It will be apparent that a plurality of magneto-strictive rods may be employed where substantial vibrational energy is required, and for this purpose a plurality of units 16 may be mounted on a single casting form. Alternatively, a single unit having two or more coil units 16 mounted upon the rigid frame 26, with the head ends 32 of the respective rods 18 secured to the diaphragm or vibrator panel, may be preferred.

Changes may be made in the construction and arrangement of the parts of my magncto-striction device for casting without departing from the real spirit and purpose of my invention, and it is my intention to cover by the claims any modified forms of structure or use of mechanical improvements which may be reasonably included within their scope.

What I claim as new and desire to obtain by Letters Patent of the United States is:

1. An apparatus for casting materials, comprising a form panel adapted to provide a surface of the casting r volume, a magneto-strictive vibrator unit fixedly mounted on said form by rigid support means, said vibrator unit including a coil and a vibrator rod, one end of said rod being fixedly secured to the surface of said panel and the other end of said rod being fixedly secured to said support means, whereby said panel serves as a vibrating diaphragm having a frequency of movement directly controlled by said coil when energized.

2. An apparatus for casting materials, comprising a form panel adapted to provide a surface of the casting volume, a frame fixedly secured to the surface of said panel and substantially conforming in contour therewith, a magneto-strictive vibrator unit fixedly mounted on said frame by rigid support means, said vibrator unit including a coil and a vibrator rod, one end of said rod being fixedly secured to the surface of said panel and the other end of said rod being fixedly secured to said support means, whereby said panel serves as a vibrating diaphragm having a frequency of movement directly controlled by said coil when energized.

3. An apparatus for casting materials, comprising a form panel adapted to provide a surface of the casting volume, a diaphragm paenl spaced from and parallel to the surface of said form panel, a fluid medium entirely filling the space between said panels, a magneto-strictive vibrator unit fixedly mounted on said diaphragm panel by rigid support means, said vibrator unit including a coil and. a vibrator rod, one end of said rod being fixedly secured to the surface of said diaphragm panel and the other end of said rod being fixedly secured to said support means, whereby said diaphragm panel serves to transmit vibrational energy to said form panel through said fluid medium when said coil is energized.

4. An apparatus for the vibration of concrete and the like in a form comprising the combination of a rigid frame having portions conforming to the shape of the form, a diaphragm comprising an integral portion of said form rigidly secured to said frame, a substantially hollow housing afiixed to said frame by a plurality of support members, coil means having a central opening detachably disposed within said housing, said housing being adapted to accommodate coil means of different sizes which may be selectively placed therein, an elongated element of magneto-strictive material disposed within said central opening, said element being fixedly secured at one end thereof to a surface of said diaphragm and means for fixedly securing the other end of said element to said housing.

5. An apparatus for the vibration of concrete and the like in a form in accordance with claim 4 wherein the stiffness of said frame is greater than the stififness of said diaphragm.

6. An apparatus for vibrating casting materials in a form comprising a frame of substantially rigid construction, said frame having attached thereto a diaphragm comprising a portion of said form, means for vibrating said diaphragm at a predetermined frequency including a housing secured in displaced relation to said frame, said housing being substantially hollow for accommodating coils of different sizes, a coil positioned within said housing, a magneto-strictive element operatively associated with said coil and having one end thereof extending through said housing, means fixedly securing said one end of the magneto-strictive element to said diaphragm for imparting vibrational energy thereto upon energization of said coil and means fixedly securing the other end of said magneto-strictive element to said housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,922,168 Lowell Aug. 15, 1933 2,032,934 Horsch Mar. 3, 1936 2,566,984 Firth Sept. 4, 1951 2,714,186 Henrich July 26, 1955

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