US 3230489 A
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Description (OCR text may contain errors)
Jan. 18, 1966 A. G. WEYRICH 3,230,489
BOBBIN WITH GROOVES IN EDGE OF FLANGE Filed Dec. 5, 1962 INVENTOR. ARTHUR a WEYRICH /6 M flaw ATTYS inside of the flange.
United States Patent 3,230,489 ,BOBBIN WITH GROOVES IN EDGE OF FLANGE Arthur G. Weyrich, Chicago, Ill., assignor, by mesne assignments, to Amer-line Corporation, a corporation of Illinois Filed Dec. 3, 1962, Ser. No. 241,733 2 Claims. (Cl. 336-192) This invention relates to a molded insulating bobbin which finds particular use in the manufacture of electrical coils. Such coils consist of a multiplicity of enameled wire windings about the bobbin. The bobbin resembles a spool or reel and is made from a plastic insulating material. The inner end of the wire, that is, the end adjacent the core or tube of the bobbin, and the outer end of the wire extending from the last winding are soldered to appropriate conductive terminals comprising part of the electrical assembly or circuit of which the electrical coil is a part.
In electrical coil constructions of this kind, it is essential that the windings be insulated from each other and that the leads also be insulated from each other. Heretofore, it has been proposed to insulate the inner end of the coil wire from all successive windings by providing an opening or slot through the flange of the bobbin to permit bringing the inner end of the wire through the flange to the outside. Thus the bobbin flange completely insulates -the Wire from the windings which, of course, are on the But such a construction exposes the inner end of the wire to other components in the circuit or in the electronic assembly adjacent to the coil.
Recently it has been proposed that an undercut pocket be provided in one flange of the bobbin between the two conductive terminals embedded therein. The sides of the pocket are adjacent the terminals. A problem exists in adequately insulating the leads when the conductive terminals are remotely spaced from the undercut pocket in the flange, for presently the wires must be taped or otherwise insulated to prevent short circuiting or damage to the insulation thereon.
An object of the present invention is to provide an improved molded bobbin wherein taping or other secondary insulation of the wire leads is unnecessary.
Another object of the present invention is to provide an improved bobbin having a pair of conductive terminal lugs thereon spaced remotely from an undercut pocket therein and grooves in the peripheral edge of the flange for receiving the leads and insulating them.
It is a further object of the present invention to provide an improved bobbin having an undercut pocket therein and a pair of conductive terminal lugs embedded in the flange on a remote side from the undercut pocket, a portion of the undercut pocket defining an insulating barrier between the leads which cross over one another before being disposed in peripheral grooves in the flange which extend from the undercut pocket to position adjacent the conductive terminal lugs.
These and other objects of this invention will become apparent from the following description when read in connection with the accompanying drawing, wherein:
FIGURE 1 is a perspective view of a bobbin made in accordance with the present invention;
FIGURE 2 is a bottom view of the bobbin shown in FIGURE 1;
FIGURE 3 is a view similar to FIGURE 2, wherein a portion of the bottom of the flange has been cut away to show the interior of the pocket defined therein; and
FIGURE 4 is an end elevation of the rear of the bob bin as shown in FIGURE 1 illustrating the crossover of the wire therein.
, Referring now to the drawing, like elements will be designated by like numerals.
In FIGURE 1, there is illustrated a bobbin construction of the present invention. The bobbin 10 comprises a tubular member 12 upon which is adapted to be wound a continuous length of wire and a pair of flanges 14 and 16 secured at each end of the tube and disposed generally at right angles thereto. The top flange 14 which comprises a generally annular disc and the bottom flange 16 together define a winding space therebetween in which the coil is wound.
The bottom flange 16 comprises a planar shelf 19 having a pair of projections 20 and 21 extending from one end thereof. Embedded in the front edges 22 and 23 of each of the projections 20 and 21 is a conductive terminal lug 24 and 25, respectively.
Defined in the bottom flange 16 on the opposite side of or remote from the projections 20 and 21 is an undercut pocket 26 through which the ends of the wire 18 extend. A slot 28 defined in the top surface of the flange 16 extends from a position adjacent the tubular member 12 to a position adjacent the end of the flange 16. The slot 28, which is tangential to the tube 12, communicates with the undercut pocket 26 along its length.
The flange 16 is provided in its peripheral edges with a pair of grooves 30 and 32 which extend from each side of the undercut pocket 26 to a position adjacent the lugs 24 and 25 in the projections 20 and 21 of the planar shelf 19.
As will be noted in FIGURE 1, the undercut pocket 26 is essentially fan-shaped or generally arcuate and is defined at the top between a lip portion 34 of the flange 16 and at its bottom by a portion 36 of the flange 16.
Considering now FIGURE 2, there is illustrated a bottom view of the improved bobbin construction of the present invention. The undercut pocket 26 is defined at each side by the sidewalls 38 and 40, respectively. It will be noted that the sidewalls of the undercut pocket 26 are each generally tangential to the tube 12 and radiate toward the edge of the flange 16 remote from the conductive terminal lugs 24 and 25. It is readily apparent from FIGURE 2 that the grooves 30 and 32 defined in the peripheral edge of the flange 16 extend from adjacent the undercut pocket 26 to a point or place adjacent the lugs 24 and 25, respectively.
Turning now to FIGURE 3, there is illustrated a bottom view similar to FIGURE 2, with parts broken away to more clearly illustrate the pocket 26 defined in the flange 16 and the manner of embedding a conductive terminal lug in an opening in the projections 20 and 21.
Within each lug there is provided, an opening 42. The lugs have arrow-like barbs 44 projecting from the faces of the lower end. Each lug is, forced into the opening 42 which is slightly smaller in height than the lug. Once the lug 24 has been seated in the opening 42, the barbs 44 prevent it from pulling out.
From FIGURE 3, it is apparent that the lead of Wire 18 which connects with the lug 24 in the projection 20 extends through and is retained in the pocket 26. The other lead passes over the lip portion 34 of the undercut pocket 26 and thus is in spaced relationship from the other lead at the crossover of the two leads. Each lead is then retained in the peripheral grooves 30 and 32, respectively, from a point adjacent the pocket 26 to a point adjacent the connection with the respective lug 24 and 25.
The insulated crossover of the two leads is also illustrated in FIGURE 4. By virtue of the foregoing, it is evident that the leads of wire 18 are maintained in the peripheral grooves 30 and 32 in the flange 16 and thus are substantially insulated along their length.
The bobbin may be integrally molded from a resinous material such as nylon, polystyrene, Bakelite, polyethylene, or similar material which has good dielectric properties and is readily molded under heat and pressure. Thermoplastic resins are preferred.
It will be appreciated that an electrical coil may be readily formed on a bobbin of the present invention. Such coils find use in a variety of applications as, for example, relay-s, transformers and inductors. One end of a continuous length of wire 18 is afiixed to a lug 24 as by winding and/ or soldering and then positioned in the peripheral groove 30. The wire extends through the undercut pocket 26 and is then wound. a plurality of times about the winding portion defined on the tube 12. After the coil has been formed, the end lead is passed back through the slot 28 defined in the flange 16 and into the groove 32 for connection to the lug 25 aflixed to the end of projection 21 on the planar shelf 19 of the flange 16. Again, the end of the continuous length of wire 18 may be suitably aflixed to the lug as by winding and/ or soldering.
It will be apparent that the improved, bobbin of the present invention may be utilized with a plurality of different electrical coil assemblies. It is, therefore, our intention to cover by the appended claims other modifica tions which may reasonably be included within their scope.
1. A bobbin integrally molded from an electrically insulating material comprising a tube and a first flange and a second flange joined to the tube at the ends thereof, said flanges being disposed substantially at right angles to the axis of said tube, a length of wire coiled about said tube between said flanges and having a pair ofleads extending therefrom, a pair of conductive terminal lugs embedded in said first flange, said first flange having a peripheral edge, an undercut pocket formed in said first flange at a place remote from said terminal lugs, and extending from adjacent said tube to said peripheral edge, said undercut pocket being defined in part by a lip portion which partially encloses the undercut pocket, a first groove in the peripheral edge of said first flange extending from said undercut pocket to a position adjacent one conductive terminal lug, a second groove in the peripheral edge of said first flange extending from said undercut pocket to a position adjacent the other conductive termi' nal, one lead of the wire extending through the undercut pocket into said first groove and being secured at it end to said one conductive terminal lug, the other lead of the wire extending over said lip portion and through said undercut pocket into said second groove in spaced and. insulated relationship with respect to said one lead, the end of said lead being affixed to said other conductive terminal lug, whereby the leads cross over one another in insulated and spaced relationship.
2. A bobbin for an electrical coil comprising a tubular member of insulating material, a first flange of insulating material attached to said, tubular member, a second flange of insulating material attached to said tubular member, there being a space defined between said first and second flanges, a length of insulated wire coiled about said tubular member in said space between said first and second flanges and having two leads extending therefrom, said. first flange having a peripheral edge, an undercut pocket in said first flange, said undercut pocket extending from adjacent said tubular member outwardly to the peripheral edge of said first flange, said undercut pocket communicating with said space through a slot extending from adjacent said tubular member to the peripheral edge of said flange, a lip portion of said flange adjacent said slot partially enclosing said undercut pocket for separating and insulating said undercut pocket from said space, a pair of terminal lugs aflixed to said first flange at a distance from said pocket, grooves in the peripheral edge of said flange extending from the sides of said undercut pocket to adjacent said terminal lugs, said two leads of said insulated wire passing through said slot and said undercut pocket in spaced relationship separated from each other at their crossover by said lip portion, said. leads being positioned in said grooves from said undercut pocket to adjacent said terminal lugs for insulating said leads along their entire peripheral path to said terminal lugs.
Brekke et al 336-4922 JOHN F. BURNS, Primary Examiner.
LARAMIE E. ASKIN, Examiner.