WO1983003495A1

WO1983003495A1 - Improved ferrite core, assembly and mounting means

Info

Publication number: WO1983003495A1
Application number: PCT/US1982/000396
Authority: WO
Inventors: Joseph F Huth Iii
Original assignee: Huth, Joseph, F., Iii
Priority date: 1982-03-29
Filing date: 1982-03-29
Publication date: 1983-10-13
Also published as: EP0105254A1; EP0105254A4; JPS59500538A

Abstract

Inductance of a coil can be influenced both by improper contact between the core elements and by relative rotation of the core elements which tends to misalign mating outer wall portions. The present invention prevents misalignment of the cores and provides an improved core and coil arrangement which is easily assembled and can be properly mounted on a circuit board. The improved assembly (10) includes a pair of ferrite core elements (12, 14) adapted to receive a coil (16) wound on a bobbin (18) and to be assembled and held in precisely aligned, abutting relation by a combination spring clip and mounting member (20). The core elements each have a pair of shallow relatively wide recesses which, when assembled, cooperate to define a pair of aligning grooves extending in substantially perpendicular relationship to mating surfaces of the core parts along the full length of the assembly on opposite sides thereof. The unitary spring clip and mounting member (20) includes a resilient portion (52) adapted to engage one core element (12), a pair of substantially straight legs (54, 56) adapted to extend along and fit closely one within each of the aligning grooves in the core assembly (10), and an inwardly directed flange (58, 60) on each leg adapted to fit over and engage the remaining core element (14) to firmly clamp the two core elements in abutting relationship. Elongated mounting posts (62, 64, 66, 68) can be integrally formed on the legs, and a stand-off lug (70, 72, 74, 76) can be integrally formed on each mounting post to facilitate mounting the assembly on a support structure such as a printed circuit board.

Description

-1- ^' *

IMPROVED FERRITE CORE, ASSEMBLY AND MOUNTING MEANS

This invention relates to core assemblies, and more particularly to improved ferrite core assemblies for inductor or transformer coils of the type commonly used on circuit boards for power supply circuits and the like. To facilitate mounting of coil windings, ferrite cores are constructed in two parts, usually substantially identical half sections, assembled with mating surfaces to provide a desired low-reluctance path for flux resulting from current changes in the coil. In such assemblies, each core element is molded from a single homogeneous mass of ferrite material and includes a center post, a radially extending web and outer wall portions or skirts extending in spaced parallel rela¬ tion to the center post. When two core elements are assembled together, their center posts cooperate to provide a central support for a coil bobbin, with the coil windings located within the space between the central support and the outer wall portions.

The mating surfaces of the skirt portions should be retained in direct, surface-to-surface engagement to provide a substantially continuous path for flux through the ferrite material in the skirt of the core. The center posts on the two core elements may also be coplanar or spaced slightly to provide a controllable air gap. Inductance of a coil can be influenced both by improper contact between the core elements and by relative rotation of the core elements which tends to misalign mating outer wall portions. Misalignment may occur even though care is exercised to initially assemble the core elements in precisely aligned relation.

Various arrangements have been proposed for retaining the coil and core elements in assembled relation; an early and conventional spring clip is shown in U.S. patent No. 3,197,167. Another approach employs flat bar members extending across the end walls of the core assembly with the ends of the bars being connected by threaded rods extending along the outer wall portions. Another approach employed in the past was to adhesively bond the opposing surfaces of the outer wall portions of the two core elements, thereby rigidly and permanently connecting the two core elements.

While ferrite cores assembled with spring clips and other known devices have been widely used, such means have not been entirely satisfactory for various reasons. For example, the spring clip devices employed generally have not retained the core half sections clamped together with sufficient force to positively prevent relative rota¬ tion after assembly. This is due, in part, to the fact that the mating surfaces on the core elements are normally very smooth, low-friction surfaces. Further, the ferrite materia is relatively brittle and subject to chipping particularly upon application of excessive or unequal clamping forces which can result from threaded fastener assemblies.

It has also been known to employ the core element clamping structure as a means for attaching an assembled inductance device to a printed circuit board or the like. For example, downwardly projecting mounting pins, or supports have been employed for attachment directed to a printed circuit board by use of -soldering or by bending the pins. Spacing elements have been employed on the clamping members for locating the inductance device a fixed distance from the surface of the board. However, these mounting devices have not always been entirely satisfactory in that they have frequently been relatively expensive to manufac- ture and/or subject to distortion in handling.

It is the primary object of the present invention to provide an improved core, core assembly, and mounting means which avoids the foregoing and other drawbacks of the prior art. Another object of the invention is to provide a core assembly wherein the component parts are more readily and easily assembled.

Another object is to provide such a core assembly which avoids the possibility of the core elements becoming misaligned after assembly.

Another object is to provide such a core assembly

P employing an improved spring clip which cooperates with aligning grooves in the core elements to facilitate aligning such core elements during assembly, and to retain the core elements in precise alignment after assembly. Another object of the invention is to provide a core assembly including a spring clip assembly having improved means for retaining the core elements in assembled relation and for supporting the assembly on a circuit board in fixed spaced relation thereto. The foregoing and other objects and advantages are achieved in a ferrite core assembly according to the present invention wherein the core is formed from a pair of ferrite core elements which may be substantially iden¬ tical and which are retained in assembled relation by an improved spring clip and mounting member cooperating with aligning means on the ferrite elements to facilitate align¬ ment during assembly and to retain the elements in precise alignment after assembly. The spring clip and mounting member is of generally U-shaped configuration, with the closed portion providing resilient spring means for engaging one ferrite core element and applying a tensile load to a pair of substantially straight inclined legs projecting one from each end of the resilient spring portion in p'osition to extend along and closely engage the skirt portions of the ferrite core elements on opposed sides of the assembly.

A substantially flat, inwardly directed retaining surface is positioned on each leg to snap over and engage the remaining ferrite element over an extended surface area when the central portion of the clip is resiliently deformed.

Each ferrite core element is formed with a pair of parallel aligning grooves, one on the outwardly directed surface of each skirt portion and extending along substan¬ tially its full length. The aligning grooves are dimen¬ sioned to receive in a self-seating, snug fitting arrange¬ ment the straight leg portions of the retaining clip so that, when assembled, the legs of the spring clip extend within the aligning groove and firmly retain the core elements to prevent skewing of the parts relative to each other. The aligning grooves each preferably have side walls which are slightly inclined outwardly from a smooth bottom wall to engage the edges of the spring clip legs in a self-seating manner to align the grooves in the two core elements during assembly. The legs of the spring clip are preferably inclined toward one another form the central portion of the spring clip in the unstrained condition and apply a resilient inwardly directed force against the ^■ aligning grooves, with the chamfered edges of the grooves engaging the edges of the legs to firmly retain the assembly against relative twisting movement after assembly.

The spring clip is preferably formed from a single length of relatively thin sheet metal spring stock with mounting posts which can be provided with integral spacing

f OMPI lugs. Smooth, relatively large bearing surfaces are pro¬ vided for engaging the ferrite material so as to minimize the likelihood of damage to the relatively brittle ferrite parts during assembly and use. Other objects and advantages of the invention will be considered in the description associated with the accom¬ panying drawings, in which:

FIG. 1 is an isometric view of an inductance device incorporating the present invention; • FIG. 2 is an exploded, isometric view of the core assembly employed in FIG. 1;

FIG. 3 is an elevation view of the spring clip and mounting element shown in FIGS. 1 and 2;

FIG. 4 is a bottom plan view of the structure shown in FIG. 3;

FIG. 5 is a view showing one step in the produc¬ tion of the spring clip;

FIG. 6 is a top plan view of one of the ferrite core elements shown in FIG. 1; FIG. 7 is a bottom plan view of a winding bobbin employed in the assembly of FIG. 1; and

FIG. 8 is an isometric view of an alternate embodi ment of the spring clip shown in FIGS. 1 - 4.

Referring now to the drawings in detail, a trans- former suitable for use in a power supply circuit and embodying the present invention is illustrated in FIG. 1 and designated generally by the reference numeral 10. The transformer assembly includes a ferrite body made up of a pair of substantially identical core elements, of half sections 12, 14, arranged in mirror image, abutting rela- tion and support a coil 16 wound on a bobbin 18. The core and coil are clamped together by a resilient spring clip and mounting element 20.

Since ferrite core elements 12 and 14 preferably are substantially identical, only element 12 will be described in detail, it being understood that the descrip¬ tion also applies to element 14,- and like reference numeral will be employed to designate corresponding parts of both core elements. Also, it should be apparent that the precise geometry of the core elements may be varied as required to produce the desired electromagnetic qualities of the trans¬ former without departing from the invention.

In the configuration illustrated in the drawings, ferrite core element 12 includes a cylindrical center post 22 integrally formed on and extending at right angles from the central portion of a web member 23. Web 23 is made up of two substantially identical, diametrically opposed sections 24, 25. A pair of outer wall portions, or skirts, 26, 28, are integrally formed one on each web section 24, 25; skirts 26, 28 extend parallel to and in outwardly spaced relation from the center post 22. Skirt portions 26, 28, respectively, have cylindrical inwardly directed surfaces 30, 32, respectively, cooperating with the cylindrical center post 22 to define an arcuate space for receiving coil 16 in a conventional manner.

The skirts 26, 28, have an aligning groove formed in their outwardly directed surface extending parallel to the center post 22. Thus, skirt 26 has an aligning groove defined by recessed planar surface 34 and inclined wall portions 38, 40 while skirt 28 has a similar aligning groove defined by recessed planar surface 36 and outwardly inclined wall portions 42, 44. As best seen in FIG. 6, the transverse width of surfaces 34, 36 is much greater than that of inclined wall portions 38, 40, 42, 44 so that the aligning grooves are relatively wide but very, shallow.

The free end surfaces 46, 48, respectively, of skirts 26 and 28 are smooth and extend in coplanar relation to one another. Surfaces 46, 48 are parallel to and may be coplanar with the flat end surface 50 of center post 22 or alternatively surface 50 may be recessed from the plane of surfaces 46, 48 whereby, when the two ferrite core elements 12, 14 are assembled together, the center posts of the two elements are spaced from one another to provide a short air gap. '

The spring clip and mounting member 20 employed to hold the two ferrite core elements 12, 14 in assembled relation is preferably formed from flat metal spring stock bent to a generally channel or U-shaped configuration defined by centrally located, concave tensioning member 52 at the closed end of the "U" and a pair of straight legs 54, 56 converging toward each other extending from each end of web 52. An inwardly directed substantially flat flange, or retaining surface area 58 is formed spaced from tensioning member 52 toward the free end portion of leg 54, and a similar flange 60 is formed on and similarly spaced toward the free end portion of leg 56.

The flanges 58, 60 are spaced from tensioning member 52 a distance such that, when the inner surface of tensioning member 52 is positioned against the outer surface of center post 22 on web 23 of the ferrite core element 12, the concave tensioning member 52 must be deflected to enable the flanges 58, 60 to be hooked over and engage the flat outer surface of ferrite core element 14 In this position, the resilient spring force of the ten¬ sioning member 52 applies a continuous axially directed clamping force holding the opposed surfaces 46, 48 of the two ferrite elements in firm contact providing a substan- tially continuous path for lines of flux through the abutting skirt portions of the two core assemblies.

The transverse width of spring clip legs 54, 56 corresponds to the transverse width of the recessed surfaces 34, 36, respectively and the length of the tensioning member 52 is such that, when assembled, the opposing surfaces of legs 54, 56 fit within the slots defined in part by surfaces 34, 36. Since legs 54, 56 normally converge, a resilient radial clamping force is applied toward the surfaces 34, 36. This clamping action is increased by the straightening, or resiliently deflecting tensioning member 52 upon final assembly, thus assuring accurate alignment of the core elements both from the standpoint of rotation and lateral displacement.

While the transverse width of the recessed sur¬ faces 34, 36 corresponds with the width of legs 54, 56, the recessed grooves defining these surfaces are preferably slightly wider at their entrances to facilitate assembly. Thus, the inclined surfaces 38, 40 can engage the side edges of leg 54 and surfaces 42, 44 can engage the side edges of leg 56 to provide a self-seating action tending to correct any slight misalignment of the tow core elements during assembly. At the same time, these inclined surfaces will act as an abuttment or shoulder engaging the edges of the legs of the spring clip and mounting assembly to posi¬ tively prevent misalignment resulting from handling, vibration or the like.

The relatively wide,- flat, radially extending surface of flanges 58, 60 provide substantial bearing surface on the end wall 23 of ferrite core element 14 to assure a substantially uniform clamping pressure and to avoid concentrated loads which could tend to chip or mar the relatively brittle surface of the ferrite core element. A pair of mounting posts 62, 64 is integrally formed on and project from the free end portion of leg 54 and a similar pair of mounting posts 66, 68 is formed on the free end portion of leg 56. Mounting posts 62, 64, 66, 68 may be employed to mount the transformer assembly 10 on a printed circuit board or the like in the conventional manner, and spacing lugs 70, 72, 74 and 76, respectively formed on the side edge portion of mounting posts 62, 64,

66, 68, respectively, can be provided to space the trans- former from the surface of the printed circuit board if desired.

As schematically illustrated in FIG. 5 the clip and mounting member 20 can be formed from a single length of flat metal spring stock 78 by initially removing, as by a die cutting operation, a generally rectangular section from each free end of the metal strip. Either at .the same time, or in a subsequent operation a pair of diverging slits is made from the bottom of each cut-out portion into the- body of the spring stock to form a pair of tongues 80, 82 which are deflected at substantially right angles to the body of the flat metal to form the flanges 58, 60. The slits can be formed to leave the generally triangular shaped spacing lugs on the opposing surface of the mounting posts. It should be apparent, however, that where the spacing lugs are not desired, the slits defining the tongues employed to shape the clamping flanges may be a continuation of the die cuts employed to form the mounting posts at each end of the strip of spring stock. The body of the spring stock can then be bent to the configuration shown in FIG. 4. If desired, the spacing lugs 70, 72, 74 and 76 5 may be deformed from the plane of the mounting posts as shown in FIG. 1.

The center posts 22 of core elements 12, 14 extend through a central, axial opening 90 in the generally spool-shaped bobbin 18 to support the coil 16 within the

-Lg ferrite core assembly. Bobbin 18 has a segmented flange 92 at each end for retaining the coil 16, with the flange segments having a shape corresponding to and extending closely adjacent the hourglass-shaped surface of web sections 24, 25 and center post 22. To retain the bobbin

-_j_5 and coil against rotation within the core, and to strengthen the bobbin flanges, a short, axially extending skirt element 94 extends along the outer peripheral edges of the flanges 92 with the skirt elements conforming to the contour of the side edge surfaces of web elements 24, 25 and the adjacent _Q edge surfaces of the skirts 26, 28.

A terminal pin mounting flange 96 projects laterally from the skirt elements 92 on one end of the bobbin and supports a plurality of terminal pins 98 for connection in an electrical circuit. Preferably the skirts 25 94 on the end of the bobbin having the terminal pins mounted thereon are slightly longer than the thickness of the ferrite web elements 24, 25 to provide protection for electrical leads extending from the terminal pins to the coil 16 from contacting the core element. Further, when the transformer assembly is mounted directly on a circuit board, the skirts 94, which project downwardly from the outer surface of core element 14, will space the ferrite core slightly from the supporting surface without benefit of the spacing lugs on the retaining clip mounting posts. The transformer shown in FIG. 1 is specially adapted for mounting on a support surface such as^" a printed circuit board with the aligning grooves in the core and the axis of the coil 16 extending perpendicular to the suppor¬ ting surface. In this embodiment, the mounting posts and the elongated legs of the spring clip and mounting member extend in coplanar relationship and in parallel relation to the terminal pins.

Other known transformer configurations are designed to be mounted with the coil axis parallel to the support surface. This may be accomplished in accordance with the present invention by use of the spring clip and mounting member 100 illustrated in FIG. 8. In this embodi¬ ment, the spring clip and mounting member is also generally U-shaped, including a resilient central portion 102, with substantially straight legs 104, 106 projecting one form each end of the resilient center portion. Legs 104, 106, terminate in inwardly directed retaining flanges 108, 110, respectively, for snapping over and engaging one core element when the other core element is in engagement with the resilient central portion. The retaining flange, legs, and central portion may be of uniform width as illustrated in FIG. 8.

Integrally formed on and projecting laterally fro legs 104,-106 are support members or mounting posts 112, 114, respectively, terminating at their distal ends in attachment tab members 116 118, respectively, of-reduced section adapted to be secured, as by bending, soldering, or the like, to a circuit board. Shoulders formed at the juncture of the attachment tabs and their associated moun¬ ting post serve to retain the transformer in spaced rela¬ tion to the supporting surface. Mounting posts 112, 114 are shaped to avoid contact with the edge surfaces of the aligning grooves in the ferrite core elements.

It will be apparent that, since the core elements 12, 14 are molded so that the center post portions 22 cooperate to provide support for the coil bobbin, the resilient spring clip will always be required to apply a clamping pressure generally parallel to the longitudinal axis- of the center posts. Thus, the aligning grooves, will similarly extend parallel to the center post, and conse¬ quently perpendicular to the abutting surfaces 46, 48 of the skirt portion of the core elements when assembled. This arrangement enables integral molding of the core elements in a single molding operation since all surfaces of the respective core elements will lie in planes either substantially parallel with or perpendicular to the longi¬ tudinal axis of the central leg and overhanging or undercut surfaces are avoided.

The ferrite core assemblies described provide improved electromagnetic characteristics through accurate and reliable alignment of the two core elements. Further, inadvertent misalignment of the core elements as^*a result of handling, vibration or the like is avoided by the cooperation of the spring clip and mounting member with the relatively wide, shallow aligning grooves integrally formed in the ferrite core elements. The spring clip not only provides uniform reliable clamping pressure and minimizes the likelihood of inadvertent damage to the ferrite element during assembly, but also readily lends itself to -use in mounting the core assembly on a mounting board in spaced relation thereto by use of the spacing lugs ^"on the mounting posts. Alternatively, the mounting posts may be employed to mount the core directly onto a support surface by eliminating the spacing lugs. The chamfered, or trough- shaped aligning grooves facilitate assembly and assure alignment of the core elements.

Since the retaining clip is made from a thin sheet metal spring stock, the legs of the clip and conse¬ quently the aligning grooves are relatively wide in

O PI comparison to the thickness of the metal legs. At the same time the aligning grooves can be very shallow and still provide the necessary aligning function. In practice, the aligning grooves will have a width at least ten times, and preferably at least twenty times their depth. Pre¬ ferably the depth of the grooves is at least equal to but not substantially greater than the thickness of the metal legs of the retaining clip.

The ferrite core assembly has been described with -particular reference to a transformer of the type frequently used in power supply circuits and the like where relatively high currents are employed. In such devices, the flux density in the core is high even with the employment of relatively larger masses of ferrite material in the core. With such high flux densities, minor misalignment of the two ferrite core elements can produce unacceptable variations in the electromagnetic characteristics of the transformer.

It is believed^* apparent, however, that the inven¬ tion is not limited to any particular inductance device or to any specific geometric configuration or electromagnetic characteristics of the ferrite core assembly. Thus, the core assembly may be a so-called E-core, pot core, or other known configuration as well as the configuration described hereinabove. Similarly, the core assembly may be of the variably reluctance type wherein the center post is conven¬ tionally formed as a tubular element and dimensioned to

OMPΓ provide a substantial air gap between opposing surfaces of the two center post elements, and wherein a ferrite plug is ovably mounted within the hollow center of the posts to vary the reluctance across the air gap. Thus, while preferred embodiments of the invention have been disclosed and described, it should be apparent that the invention is not so limited and it is therefore intended to include all embodiments which would be apparent to one skilled in the ^•art and which come within the spirit and scope of the invention.

Claims

CLAIMS 1. A ferrite core assembly having stable electro- magnetic characteristics comprising, in combination, first and second ferrite core elements adapted to be assembled together to retain a coil therebetween such ferrite core elements each being molded from a single substantially homogeneous mass^"of ferrite material and including a center post, skirt portions extending in outwardly spaced relation and generally parallel-to the center post on opposite sides thereof, and web portions projecting substantially perpendicular to and joining one end of the center post and the skirt portions, a pair of elongated recesses formed in the out- wardly directed surface of such skirt portions of each said ferrite core element, such recesses extending parallel to and being located on opposite sides of said center post and being positioned so that when the first and second core elements are assembled, the recesses are aligned and cooperate to form two continuous aligning grooves extending along at least a major portion of the length of the core assembly, and retaining clip means adapted to engage and resiliently clamp the first and second ferrite core elements in assembled relation, the retaining clip means including resilient means adapted to engage the first ferrite core element, a pair of substantially elongated legs adapted to extend along the skirt portions of the first and second core elements, and retaining means on each such leg in position to engage the second ferrite core element, such elongated legs being dimensioned to fit one in each of the aligning grooves and to engage the first and second ferrite core elements within the aligning groove to retain the ferrite core elements against relative rotation. 2. ' The ferrite core assembly defined in claim 1 wherein the retaining means on each such leg comprises a flange having a flat surface extending at substantially right angles to the associated leg, the flat surface being adapted to engage the web portion of the second ferrite element. . 3. The ferrite core assembly defined in claim 2 further comprising at least one mounting post integrally formed on each leg of the retaining clip-means. 4. The ferrite core assembly defined in claim 3 wherein the width of the flange on each such leg is less than the width of the leg, and wherein a pair of such mounting posts are formed on each leg one on each side of such flange. 5. The ferrite core assembly defined in claim 4 further comprising spacing means integrally formed on each such mounting post such spacing means being adapted to engage a supporting surface on which the core assembly is mounted to space the core assembly from the surface-. OMPI 6. The ferrite core assembly defined in claim 4 wherein such mounting posts are formed on and project laterally from one side edge of such legs. 7. The ferrite core assembly defined in claim 6 further comprising spacing means integrally formed on each such mounting post such, spacing means being adapted to ^* engage a supporting surface on which the core assembly is mounted to space the core assembly from the surface. 8. The ferrite core assembly defined in claim 1 wherein such aligning grooves are each defined by a bottom surface and substantially flat edge wall surfaces extending from such bottom surface to the outer surface of the associated skirt portion, and wherein the legs on such retaining clip have a transverse width corresponding to the width of the bottom surface of the aligning groove between such edge wall surfaces whereby the legs on the retaining clip means engage the flat edge wall surfaces when positioned ,in the retaining grooves. 9. The ferrite core assembly defined in claim 8 wherein said edge walls of said aligning grooves extend in outwardly diverging relation from the bottom surface to act as camming surfaces to engage the side edge- portions of the legs of the retaining clip to cam the ferrite core elements into accurate alignment as the legs of the retaining clip are positioned in the aligning grooves. 10. The ferrite core assembly defined in claim 9 wherein the retaining means on each such leg of the retaining clip comprises a flange member having a flat surface extending^' at substantially right angles to the associated leg, the flat surface being adapted to engage the second ferrite element. 11. The ferrite core assembly defined in claim 10 wherein the flange member has a transverse width less than the width of the legs on the retaining clip means, and further comprising a pair of mounting posts integrally formed on the end portion of each leg of the retaining clip, one adjacent each side edge of the associated flange. 12. The ferrite core assembly defined in claim 11 further comprising spacing means integrally formed on each such mounting post. 13. The ferrite core assembly defined in claim 10 wherein such mounting posts are formed on and project laterally from one side edge of such legs. 14. The ferrite core assembly defined in claim 13 further comprising spacing means integrally formed on each such mounting post such spacing means being adapted to engage a supporting surface on which the core assembly is mounted to space the core assembly from the surface. 15. Magnetically soft ferrite component assembly comprising, in combination a pair of matching ferrite core parts, each having a center post symmetrical about a centrally located axis, a web extending from one end of the center post in transverse relationship to such axis, and a skirt extending from the web in generally parallel spaced relation to the center post defining winding coil space between the center post and the skirt, each skirt having a mating surface to be held in substantially coplanar relationship with the corresponding mating surface of a remaining core skirt, such coplanar mating surfaces being in transverse relationship to flux paths through the skirts of both ferrite core parts which are^' complete through the center posts and webs, as assembled, each core skirt having an elongated slot-like groove extending along its exterior surface in a direction which is substantially perpendicular to the plane of the mating surfaces of the skirts of the core halves, a bobbin, for supporting coil windings, adapted for mounting on such core part central legs with such coil windings in the defined space between the center post and skirt portions of the core parts, and a unitary clip of resilient material holding such core parts in assembled relationship with such skirt mating surfaces in substantially coplanar relationship, the unitary clip including an elongated spring-tensioning member extending in transverse relationship to the centrally elongated axis of a core part contacting such core part in a plane along the exterior surface of its web contiguous to its center post, with a leg extending in substantially right-angled relationship from each longitudinal end of such tensioning member along the external surface of the skirt of each core part and seated in and cooperating with the slot-like groov defined in each ferrite core part skirt to prevent relative rotation between the two ferrite core parts each such leg including a shelf-like flange of extended surface area extending transversely to the direction of such leg toward the centrally located axis of the core parts for contacting the web surface of the remaining core part of the assembly, each such flange being substantially equally spaced from the tensioning member and located a predeter- mined distance along each leg so as to clamp the pair of core parts together when assembled. 16. The component assembly according to claim 15 wherein' such elongated slot-like grooves each have a substantially flat bottom surface and substantially flat edge wall surfaces, the bottom surface having a width substantially greater than the depth of the slot-like groove, and wherein such legs are substantially flat and have a width substantially equal to the width of the flat bottom surface of the slot-like grooves. 17. The ferrite core assembly defined in claim 16 wherein such edge wall surfaces extend in outwardly diverging relation from the bottom surface and act as camming surfaces for engaging the side edge portions of the unitary clip_^ legs to cam the core parts into accurate alignment as the legs are positioned in the slot-like grooves. 18. The ferrite core assembly defined in claim 17 further comprising at least one mounting post integrally formed on each such leg of the unitary clip. 19. The ferrite core assembly defined^'in claim 18 further comprising spacing means on each such mounting post. 20. For use in a ferrite core assembly having a pair of ferrite core elements adapted to be assembled together to retain a coil therebetween, the ferrite core elements each being molded from a single substantially homogeneous mass of ferrite material and including a central leg, two skirt portions extending generally parallel to and spaced from the central leg on the opposite side thereof, and a web extending substantially perpendicular to and-joining the central leg and skirt portions at one end thereof, and a pair of aligning grooves formed one in the outwardly directed surface of each skirt portion of each ferrite core element, the aligning -grooves in the two core elements being positioned to be aligned when the two core elements are assembled toegether to form two continuous aligning grooves extending substan- tially the full length of the core assembly, an improved retaining clip and mounting member for retaining the ferrite core elements in assembled relation and for mounting the assembly on a supporting surface, comprising, an elongated resilient^' spring element adapted to extend across and engage one of the ferrite core- elements, a pair of substantially straight legs adapted to. extend along the skirt portions of the two core elements, a pair of flat, inwardly directed flanges formed one^' on the end portion of each said leg in position to engage the other of the ferrite core elements, said elongated legs being dimensioned to fit within the aligning groove and to engage the ferrite core elements within the aligning groove to positively retain the ferrite core elements in accurately aligned relation, mounting means including at least one mounting . post integrally formed on each leg of the retaining clip and spacing means independent of said flanges inte- grally formed on each said mounting post, the retaining clip being formed from a single piece of flat metal spring stock material .

OMPI - 21. In a ferrite core assembly including two matching core elements having mating surfaces retained in abutting relation by a spring clip, the core elements each including a center post, skirt portions extending in parallel relation to and laterally spaced from the center post, and a web portion joining one end of the center post and the skirt portions, the improvement wherein the core elements further comprise, a pair of shallow aligning grooves formed in the outer surface of the skirt portions in substantially diametrically opposed relation to the center post, the aligning grooves extending substantially parallel to the center post and extending substantially the full length of the skirt portions, the aligning grooves having a bottom wall and. outwardly chamfered side edges diverging from the bottom wall, the width dimension of the bottom wall being at least ten times as great as the depth of the aligning grooves, the aligning- grooves intersecting the mating surfaces on the associated core element and being arranged on the skirt portions so that when the two matching core elements are assembled, the aligning grooves in the two core elements cooperate to define two continuous aligning grooves extending substantially the full length of the core assembly.