US 3428929 A
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F 1969 I M. H.. BRIOVWN ETAL I 3,428,929
COIL RECEIVING STRUCTURE 32 Filed May 12, 1967 Y F 5.1. 38 F75.2.
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United States Patent 3,428,929 COIL RECEIVING STRUCTURE Maurice H. Brown, Palos Heights, and George F. Linning, Des Plaines, Ill., assignors to Amerline Corporation, a corporation of Illinois Filed May 12, 1967, Ser. No. 638,069 US. Cl. 336-129 Int. Cl. H01f 21/04 9 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention and description of the prior art This invention relates to an improved coil receiving structure and it particularly relates to a structure for mounting first and second coils at a predetermined lateral spacing.
Coil structures having a pair of coils in spaced relationship to each other on the same core are commonly used in radio and television sets. These coil structures are commonly used as interstage transformers to inductively couple a pair of cascaded tuned circuits, such as radio and television LF. (intermediate frequency) amplifiers. In such assemblies, varying the number of turns in one coil alters the inductance of that coil while variations in the spacing between the two coils alters their mutual inductives. These coils may also be permeability tuned by moving a slug of magnetic material axially through the central core of that bobbin.
Generally, the spacing between two such coils is determined empirically by the television or radio set manufacturer. After the spacing has been empirically determined, a coil structure with two spaced coils is made up so that the coils are at the empirically predetermined spacing on a cylindrical core.
Occasionally, bobbins having two pairs of spaced flanges at the predetermined spacing are made of molded plastic. In these constructions, the flanges are thus fixed at the predetermined spacing. Such molded bobbin structures, however, have significant disadvantages. In a television set, for example, a large number of these coil structures are used. The spacing of the flanges on the core and the coil sizes are, however, generally difierent from one another. This requires a large inventory of such molded bobbins to be maintained by the manufacturer for each type of television or radio chassis. The maintenance of a large inventory of parts is generally considered to be highly disadvantageous because of problems in storage and added expense. A further disadvantage of providing such molded bobbin structures is the result of the criticality of the spacing between the coils. For example, even after the spacing has been predetermined and the parts molded, the spacing of the coils may later have to be changed after a television set goes into production to correct certain deficiences in the operation of the set. For a given television set, there may be several times when the spacing of the coils of such a molded structure must be changed. Every time a change is required, it is necessary for the manufacturer to have a new mold made to provide a bobbin structure having flanges at the new spacing. Since new molds are required each time a new spacing is required, it becomes excessively expensive. Thus, the use of molded plastic bobbins wherein pairs of flanges are molded at a fixed spacing is very limited.
Because of the above problems of the described molded plastic bobbins, they have not generally been used by manufacturers. Rather manufacturers have used pairs of spaced self-sustaining coils wound about a cylindrical hollow core. When self-sustaining coils are used, after a manufacturer determines the desired spacing, the coils are wound and secured to the core at the desire-d spacing. Since the coils are self-sustaining, no flanges are required and the spacing can be easily changed. The manufacturer simply changes the place that the particular coils are wound upon the core, and it is not necessary to make new molds. The self-sustaining coils avoid the problem of maintaining a large inventory since only a few cylindrical cores would have to be maintained in stock.
Although the self-sustaining coils avoid the disadvantages of the above described molded plastic bobbins, they have one significant drawback in that self-sustaining coils are quite expensive to wind because of the way they must be wound to be self-sustaining. Randomly wound coils provide the same results as self-sustaining coils but do not require any special type of winding procedure. The randomly wound coils, however, do require the use of flanges to hold them in place.
SUMMARY OF THE INVENTION It is therefore an important object of this invention to provide an improved coil receiving structure which avoids the disadvantages of the prior art structures of the type which have pairs of spaced coils mounted on a single core.
It is also an object of this invention to provide an improved coil receiving structure wherein the structure, which is made of a molded plastic material, has the spaced coils randomly wound between flanges and yet the spacing between the two coils is readily adjustable.
It is another object of this invention to provide a coil receiving structure for mounting spaced coils wherein only a single coil structure needs to be maintained in inventory for accommodating a large variety of such coil receiving structures.
It is yet another object of this invention to provide an improved coil receiving structure for mounting pairs of coils wherein the structure is particularly characterized by its simplicity and economy of construction, manufacture, and use.
Further purposes and objects of this invention will appear as the specification proceeds.
The foregoing objects are accomplished by the provision of a coil receiving structure having a core, with a first pair of spaced flanges on the core for receiving a first coil or wire, at least one bobbin slidaby mounted on the core for receiving another coil of wire, and cooperating means on said bobbin and on said core for adjustably looking said bobbin and said second coil at a predetermined spacing from the first coil.
BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, there is shown one particular embodiment of the present invention, wherein:
FIGURE 1 is a side elevational view of our improved coil receiving structure;
FIGURE 2 is an end view of the embodiment of FIGURE 1;
FIGURE 3 is an enlarged cross-sectional view taken along the line 3-3 of FIGURE 2 showing the details of construction for the coil receiving construction of FIGURE 1;
FIGURE 4 is an end view of the embodiment of FIG- URE 3, which is at the end of the structure opposite to that shown in FIGURE 2;
FIGURE 5 is a cross-sectional view through the coil receiving structure, taken along the line 55 of FIG- URE 3;
FIGURE 6 is a cross-sectional view through the coil receiving structure, taken along the line 66 of FIG- URE 3;
FIGURE 7 is a fragmentary cross-sectional view through the coil receiving structure taken along the line 77 of FIGURE 3; and
FIGURE 8 is a fragmentary, transverse cross-sectional view through the coil receiving structure taken along the line 8-8 of FIGURE 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and particularly to FIG- URES 1 and 3, our improved coil receiving struct-ure, generally 10, comprises a first elongated coil receiving member, generally 12, and a second coil receiving member or bobbin, generally 14, slidably received by the first coil receiving member 12.
The first coil receiving member 12 has an elongated hollow core 16 and a pair of spaced integral parallel flanges 18 defined thereon at a point intermediate the opposite ends of the core 16. The flanges 18 are generally circular in shape as shown in FIGURE 5 and extend radially outwardly from the hollow core 16. The circular flanges 18 cooperate with the core 16 to define a winding space 20 for receiving a randomly wound electrical coil 22.
The core 16 includes an electrical terminal receiving portion 24 having an enlarged circular base 26. As best shown in FIGURES 3 and 4, the base 26 includes a plurality of arcuately spaced upright terminal receiving slots 28. The upright slots 28 receive metal terminals 30 therein. Each of the terminals 30 includes an upper outwardly extending bent portion 32 and downwardly projecting connector portions 34. The connector portions are for electrical connection to the opposite leads 36 of the coil 22 and to the leads 38 of a second coil 40. The downwardly projecting portions 34 are connected to external circuit components. The slots 28 are positioned radially outwardly of the main portion of the core 16 and are elongated in a direction perpendicular to radii extending from the central axis of the core 16. The terminals 30 are secured within the slots 28 in any suitable way. In the embodiment shown, the terminals are secured to the enlarged portion 32 of the base 26 by being bent into locking engagement with the opposite sides of the base portion 26. The bobbin flanges 18 are spaced from the base 26 to provide ease of connection between the leads 36 and 38 and the lead connector portions 32 of the terminals 30.
The bobbin receiving portion 42 of the core 16 extends from the flanges in a direction opposite to that of the terminal receiving portion 24. The bobbin receiving portion 42, like the terminal receiving portion 24, is in the general form of an elongated cylinder.
The bobbin, generally 14, is slidably received on the bobbin receiving portion 42 of the core 16. The bobbin 14 includes a pair of parallel, circular flanges 46 which, when mounted upon the core 16, are substantially'parallel with the first pair of flanges 18. The bobbin flanges 46 are interconnected by a plurality of arcuately spaced ribs 48 which are substantially parallel with the central axis of the core 16. The ribs 48 interconnect the flanges 46 to thereby define the bobbin structure 14. Windows 50 are defined between the ribs 48 and the opposite flange 46. As will be explained hereinafter, the windows cooperate with the windings of the coil 40 to lock the bobbin 14 at a predetermined position on the core 16.
Referring to FIGURES 3 and 6, the inner periphery of one or more of the ribs 48 preferably includes an inwardly projecting arcuate portion 52 for providing secure sliding and abutting relationship with the core 16 to assist in maintaining the bobbin 14 in a fixed relative position on the core 16. The arcuate projection 52 is received within an elongated longitudinal depression 54 on the surface of the core 16. One or more depressions 54 are provided in the core 16 depending upon the number of the ribs 48 with projections 52.
Alternatively, one or more of the ribs 48 include an inwardly projecting tooth 56 for engaging one of the teeth 58 provided in a longitudinal depression 60 in the core 16, as best shown in FIGURE 8, wherein two toothed depressions are shown. The use of the tooth 56 on the ribs 48 for engaging the teeth 58 in the depression 60 provides for positively locking the bobbin 14 at the predetermined spacing from the flanges 18. When no teeth 58' are in the depression 60 or teeth 56 on the ribs 48, infinite adjustment is possible between the flanges 18 and the bobbin flanges 46. When the teeth 56 and 58 are used, the spacing between the flanges 46 and bobbin 14 is limited by the distance between the valleys of the teeth. The projections 52 and/or projections 56 also cooperate with the depressions 54 and/ or 60 to prevent rotation between the bobbin 14 and the core 16.
The windows 15' defined between the ribs 48 on the bobbin 14 cooperate with the inner layers of wire on the coil 40 to lock the relative position of the bobbin 14 on the core 16. The wires of the coil 40 pass across each of the windows and bear against the arcuate outer segments on the surface of the core 16 to thereby lock the bobbin 14 in a fixed relative position on the core 16. Referring to FIGURE 6, it is important that the outer arcuate surface of the core 16 between the ribs 48 extends beyond an imaginary plane P passing tangentially across the outer surfaces of the ribs 48. In this way, the wires of the coil 40 bear against the core 16 to lock the bobbin 14 in a position on the core 16 at a predetermined spacing from the flange 18.
In using the coil receiving structure 10, it is necessary only for the manufacturer to maintain in stock structures 10, which permits adjustment of the relative spacing of coil pairs. It is thus not necessary for the manufacturer to maintain a large supply of coil receiving structures for receiving pairs of coils. The manufacturer merely needs to purchase a single mold for the coil receiving structures 10 to maintain an inventory of these parts for substantially all such structures required in a particular television or radio set. The manufacturer has full freedom in varying the spacing between the coils wound on the structure.
Furthermore, the coils wound between the flanges 18 and on the bobbin 14 are the randomly wound type, which are far more economical than self-sustaining coils. The randomly wound coils are used since the flanges 18 and 46 maintain the coil 22 and the coil 40 in position. Although the described structure 10 shows one fixed set of flanges, it is obvious that all the sets of flanges on the structure 10 could be adjustable.
After the terminals 30 are positioned in the terminal receiving portion 24 of the coil receiving member 12, the coil 22 is wound upon an automatic winding machine. The beginning lead wire is passed through a radial slot or opening 62 in the flange 18 facing the terminal receiving portion 24. After the beginning lead wire is secured to a terminal 30 and after the end wire is secured to another terminal 30, the predetermined spacing between the coil 22 and the coil 40 to be wound upon the bobbin 14 may be set by means of a jig. After the spacing is set, the wire of the coil 40 is wound about the bobbin 44. Again, a radial slot 64 is provided in a flange 46 to permit the passage of the lead wire of the coil 40. During the winding operation, the wire from the coil 40 bears against the core 16 by passing across the windows 50 to thereby lock the bobbin 14 in a fixed position on the core 16 at a predetermined distance from the coil 22. After the proper number of turns has been wound about the bobbin 44, the lead wires 38 are soldered to the terminals 30. A structure having a pair of randomly wound coils at a predetermined spacing is thus provided.
While in the foregoing, there has been provided a detailed description of particular embodiments of the present invention, it is to be understood that all equivalents obvious to those having skill in the art are to be included within the scope of the invention as claimed.
What we claim and desire to secure by Letters Patent 1s:
1. A coil receiving structure for receiving at least two coils of wire thereon, said structure comprising a core, a pair of spaced flanges on said core receiving one of said coils of wire therebetween, a bobbin with flanges slidably mounted on said core receiving another of said coils of wire, means interconnecting said bobbin flanges, said interconnecting means being unitary with said bobbin flanges, and cooperating means on said core and on said bobbin for locking said bobbin in a fixed relative position to said pair of spaced flanges.
2. The bobbin of claim 1 wherein said spaced flanges are unitary with said core.
3. The device of claim 1 wherein said core and said pair of spaced flanges are integrally molded of a plastic material, and said bobbin including said bobbin flanges and said interconnecting means are unitary and are molded ofplastic material.
4. The device of claim 1 wherein said interconnecting means includes means permitting the wire of said another coil to bear against said core and lock said bobbin in position on said core.
5. The device of claim 4 wherein said interconnecting means comprises a plurality of spaced, substantially parallel ribs interconnecting said bobbin flanges having apertures therebetween, and said apertures are sufliciently large so that a tangential plane passing across the top of said ribs intersects said core so that said wire bears against said core.
6. The device of claim 1 wherein said interconnecting means comprises a plurality of spaced, substantially parallel ribs interconnecting said bobbin flanges, longitudinal grooves are provided in the outer surface of said core, and means are provided on the inner periphery of said connecting ribs for engaging the slots in said core whereby said bobbin is maintained in a substantially fixed position on said core.
7.- The device of claim 6 wherein at least one of said grooves in said core has teeth, and at least one of said ribs has means for engaging said teeth to positively lock said bobbin in a fixed position relative to said flanges on said core.
8. The device of claim 1 wherein said core includes a first portion which extends from one side of said spaced flanges, said bobbin is slidably received on said first portion, a second portion is on the opposite side of said pair of flanges, and electrical terminals are mounted on said second portion for connecting the lead wires of each of said coils to an external circuit.
9. The device of claim 7 wherein a radial slot is provided in one of said flanges on said core, and a radial slot is provided in one of the bobbin flanges, said radial slots provided entrance means for the lead wires of each of said coils.
References Cited UNITED STATES PATENTS 2,062,016 11/ 1936 Serrurier 242-569 2,533,307 12/1950 Amos et al. 242-75.5
3,153,519 10/1964 Jewell et al. 24256.9 XR
3,355,687 11/1967 Adams 336208 XR FOREIGN PATENTS 1,205,463 8/ 1959 France.
LEWIS H. MYERS, Primary Examiner.
T. J. KOZMA, Assistant Examiner.
US. Cl. X.R.