Abstract:
An apparatus for winding the magnetic core of an electronic transformer about a pre-formed wire coil, the apparatus comprising a first member, a second member, and a locking device for aligning and fastening said first member to said second member. The first member and the second member each further comprising a winding member, a first flange disposed at a first end of said winding member, and a second flange disposed at a second end of the winding member. A method of continuously winding a magnetic material onto a bobbin assembly to form a wound core of an electrical transformer is provided and comprises forming a bobbin assembly about a pre-formed wire coil, fixing a leading edge of the magnet material to the bobbin assembly, and rotating said bobbin assembly about the pre-formed wire coil to wind the magnetic material onto the bobbin assembly.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the field of electrical transformers and inductors and particularly to a method and an apparatus for constructing continuously wound magnetic cores of transformers and inductors. 
     Transformers and inductors and the construction thereof is common in the art. FIG. 1 depicts an exemplary electrical transformer known in the art, shown generally at  10 . The transformer  10  comprises a double coil transformer having a first coil bobbin  12  and a second coil bobbin  14 . Each of the coil bobbins  12  and  14  typically has a turn wire (not shown) wrapped about the bobbin. The turn wire of the first coil bobbin is connected to the turn wire of the second coil bobbin by an electrical wire  16 . The electrical wire  16  terminates in a prong  18  which provides a means for connecting the transformer  10  to another device. The first and second coil bobbins  12  and  14  include openings  20  and  22 , respectively. 
     The electrical transformer  10  further comprises a wound core of magnetic material  24 . The magnetic material  24  is wound about both the first coil bobbin  12  and the second coil bobbin  14  through the openings  20  and  22 , respectfully, to form a magnetic transformer core  26 . The magnetic material  24  is typically a magnetic strip wound to a predetermined thickness and cut to form a trailing edge  28 . The trailing edge  28  is secured to the underlying magnetic material  24  by welding or other common adhesive process. 
     There are several common practices known in the art for assembling the magnetic material  24  within the transformer  10  to form the magnetic transformer core  26 . In one method, the transformer core  26  is formed out of a stack of laminations which are constructed utilizing commonly known techniques such as interleave, butt-stack, etc. The second commonly implemented method for constructing the magnetic core  26  of an electrical transformer  10  involves assembling two pre-formed cut magnetic core halves about the wire coil. Although commonly implemented, these methods of manufacturing the magnetic core elements of electrical transformers are very time consuming and costly to the manufacturer. 
     Another known method for assembling magnetic transformer cores utilizes a core winding mechanism which winds a magnetic material in and through openings formed in a wire coil bobbin such that the leading edge of the magnetic material is continuously threaded through the opening(s) formed in the bobbin(s) to form a wound transformer core. In effect, this method pushes the magnetic material through the opening of a wire coil bobbin to form a magnetic core there about. The resulting magnetic core is fashioned into a predetermined shape such as a rectangle, etc. 
     This winding method, however, encounters difficulties when utilizing certain magnetic materials. Thin magnetic materials tend to buckle and jam the winding mechanism when forced in and about the coil bobbins thus inhibiting the winding process. Thick or hard magnetic materials form bulkier magnetic transformer cores. Higher stresses are placed upon the thick material thus resulting in the degradation of the magnetic properties of the material. Further, a winding mechanism as described above is insufficient in attaining a prescribed tension of the magnetic core material, especially when thick or hard magnetic material is used. 
     U.S. Pat. No. 4,592,133 to Grimes et al (&#39;133), incorporated fully herein by reference, teaches a method of constructing an electrical transformer which entails winding an electrical wire about a pre-formed laminated magnetic core. Similarly, U.S. Pat. No. 5,860,207 (&#39;207) to Knight et al, incorporated fully herein by reference, teaches a method of constructing an electrical transformer by preforming a laminated magnetic transformer core and winding a conducting coil about said core by use of a winding bobbin. However, neither the &#39;133 nor the &#39;207 patent teaches a winding technique for the construction of the transformer core, thus both referenced patents require implementation of costly and time consuming traditional core manufacturing methods as are discussed herein above. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a continuous core winding process and a winding apparatus used to produce electrical transformers. In its assembled state the electrical transformer may comprise at least one pre-formed wire coil with at least one magnetic core wound about said wire coil, in accordance with the present invention. 
     In an exemplary embodiment, the apparatus includes a first member and a second member. The first member is identical in description to the second member each comprising a winding member, a first flange, a second flange and a locking assembly. The winding member is substantially semi-cylindrical in shape with a convex outer surface and a concave inner surface. The first flange and the second flange are semi-circular in shape and include meshing protuberances or gear teeth on their circumferential edge. The first flange is mounted at one end of the winding member perpendicular to said winding member. The second flange is mounted perpendicularly at an end of the winding member opposite the first flange. The locking assembly includes a locking post and lock pin for securing the first member to the second member. 
     In an exemplary embodiment, the method of the present invention includes securing the first member to the second member about a pre-formed wire coil to form a bobbin assembly, fixing a magnetic material to the bobbin assembly, engaging the bobbin assembly with a drive mechanism, operating the drive mechanism to rotate the bobbin and thus wind the magnetic material about the bobbin assembly. The drive mechanism of the present invention may utilize a servo type motor to implement a prescribed number of revolutions to the bobbin assembly and to apply a specified tension to the wound magnetic element. 
     The above discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed descriptions and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
     FIG. 1 is a front elevation view of a conventional electrical transformer of the prior art; 
     FIG. 2 is a perspective view of a split core bobbin in accordance with the present invention; 
     FIG. 3 is an exploded perspective view of the split core bobbin of FIG. 2; 
     FIG. 4 is a side elevation view of one half of the split core bobbin of FIG. 2; 
     FIG. 5 is an end elevation view of one half of the split core bobbin of FIG. 3; 
     FIG. 6 depicts a first step of a method of constructing a continuous wound magnetic core for electrical transformers and inductors in accordance with the present invention; 
     FIG. 7 depicts a second step in the method of constructing a continuous wound magnetic core for electrical transformers and inductors in accordance with the present invention; 
     FIG. 8 shows a third step in a method of constructing a continuous wound magnetic core for electrical transformers and inductors in accordance with the present invention; 
     FIG. 9 shows another step in a method of constructing a continuous wound magnetic core for electrical transformers and inductors in accordance with the present invention; 
     FIG. 10 is an alternative application of the method in accordance with the present invention; and 
     FIG. 11 is an alternative application of the method in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2 shows a perspective view of a split core bobbin assembly  100  in accordance with the present invention. The core bobbin assembly  100  includes, generally, a first core bobbin half  102  and a second core bobbin half  104 . The first core bobbin half  102  is secured to the second core bobbin half  104  by a locking and alignment assembly  106 , as is discussed further herein below. FIG. 3 shows an exploded perspective view of the split core bobbin assembly  100 . 
     FIG. 4 shows a side elevation view of the first core bobbin half  102 . The first core bobbin half  102  includes a first flange  108 , a second flange  110 , a winding member  112 , and the locking and alignment assembly  106 . The first flange  108  is fixed at one end of the winding member  112  perpendicular to the winding member  112 . The second flange  110  is fixed to the end of the winding member  112  opposite the first flange  108 . The second flange  110  is positioned relative to and parallel with the first flange  108 . 
     Referring to FIGS. 3 and 4. The winding member  112  is generally semi-circular and includes a winding surface  114  and a mounting surface  116 . The winding surface  114  is generally convex in shape and is of a predetermined radius to fit about a coil bobbin and to accommodate a prescribed magnetic material, as is discussed further herein below. The mounting surface  116  is generally concave and is approximately congruent to the winding surface  114  thus creating hollow  115 , as shown in FIG.  3 . The edges of the mounting surface  116  of the first split core bobbin half  102  contact the edges of the mounting surface of the second split core bobbin half  104  when the split bobbin assembly  100  is fully assembled as depicted in FIG.  2 . 
     Referring again to FIG. 4, the first and second flanges  108  and  110  are mounted to the winding member  112  as discussed herein above such that the first flange  108  and the second flange  110  are flush with the mounting surface  116  at one end and extend beyond the winding surface  114  of the winding member  112  at the other end. The first flange  108  includes the locking and alignment assembly  106  which is disposed on the first flange  108  parallel to the longitudinal axis of the first flange  108  such that the locking and alignment assembly  106  extends perpendicularly from the winding member  112 . The second flange  10  includes a second locking and alignment assembly  106  disposed parallel to the longitudinal axis of the second flange member  110  extending perpendicularly from the mounting surface  116 . The locking and alignment assemblies  106  assist in positioning and securing the first core bobbin half  102  to the second core bobbin half  104  when mounted about a wire coil in transformer/inductor assemblage, as is discussed more fully herein below. 
     FIG. 5 shows a front elevation view of the first flange member  108  of the first bobbin half  102 . The first flange member  108  is substantially semi-circular in shape and includes a serrated surface  118 , a locking pin  107 , the locking and alignment assembly  106 , and the mounting surface  116 . The serrated surface  118  comprises the circumferential surface of the first flange member  108 . The serrated surface  118  may contain gear teeth or similar meshing protuberances for engaging a pinion wheel drive motor assembly during the continuous transformer core winding technique in accordance with the present invention, as is discussed further herein below. The locking and alignment assembly  106  is disposed on the first flange member  108  such that the assembly  106  extends beyond the first flange member  108  in a direction away from the pinion surface  118 . The locking and alignment assembly  106  is formed of a locking post  122  and a lock pin mating port  120 . The locking post  122  preferably comprises a rectangular member extending from and integral to the flange  108 . The lock pin mating port  120  is disposed on the portion of the locking and alignment assembly  106  which extends beyond the mounting surface  116 . The locking pin  107  may be a protuberance which is disposed on the first flange  108  a predetermined distance from both the locking and alignment assembly  106  and the mounting surface  116 . The locking and alignment assembly  106  and the lock pin  107  are each positioned on the first flange  108  so as to properly mate with a second lock pin and a second locking and alignment assembly, respectively, of a second split bobbin half when constructing the core bobbin assembly  100  in accordance with the present invention, as is discussed further herein below. Referring again to FIG. 4, the construction of the second flange  110  is substantially identical to that of the first flange  108  herein discussed above. The positioning of the locking and alignment assembly  106  and the lock pin  107  on the second flange  110  may be identical to the positioning on the first flange  108  or may be reversed relative to the positioning of the assembly  106  and the pin  107  on the first flange  108 . 
     The second core bobbin half  104  is identical to the first core bobbin half  102  discussed herein above. Thus, to avoid the confusion of repetition and to preserve brevity, a detailed description of the second core bobbin half  104  has been omitted, with reference, instead, to the above description of the first core bobbin half  102 . It is understood that the first core bobbin half  102  and the second core bobbin half  104  are symmetrical in nature so that the two may mate with one another. 
     Referring now to FIGS. 6-8, the method for continuous magnetic core winding of electrical transformers and inductors, in accordance with the present invention, is depicted. FIG. 6 shows an exemplary first step of the method in accordance with the present invention. FIG. 6 depicts a side elevation view of a pre-formed wire coil  200 , the first core bobbin half  102 , and the second core bobbin half  104 . The wire coil  200  may be any of a plurality of wire coils known in the art, constructed in any of a plurality of methods common to the art. 
     An exemplary method of continuous magnetic core winding of electrical transformers in accordance with the present invention may begin by constructing the core bobbin assembly  100  about the wire coil  200 . The first core bobbin half  102  is positioned about a portion of the wire coil  200 . Next, the second core bobbin half  104  is brought in the direction of arrow  202  into position with the first core bobbin half  102 . The second core bobbin half  104  is positioned such that the mounting surfaces  116  of the first core bobbin half  102  and the second core bobbin half  104  are brought into contact about the wire coil  200 . In FIG. 7, the second core bobbin half  104  is secured to the first core bobbin half  102  by mating the locking and alignment assemblies  106  with the respective locking pins  107 . The lock pins  107  are received in the lock pin mating ports  120  of the respective locking posts  122  (FIG.  5 ). Securing the core bobbin halves  102  and  104  about the wire coil  200  in this manner insures proper mating and alignment of the first and second core bobbin halves  102  and  104  thus properly forming the core bobbin assembly  100  as depicted in FIG.  7 . Properly formed in the above discussed manner, the bobbin assembly  100  is free to rotate about a portion of the wire coil  200 . 
     FIG. 8 depicts the next step of an exemplary method of continuous magnetic core winding of electrical transformers in accordance with the present invention. A magnetic material  210  is fixed to the winding surface  114  of the bobbin assembly  100 . The magnetic material  210  may be secured to the bobbin  100  by implementing any of a plurality of common adhesive techniques including, but not limited to, using adhesive tape and other techniques, such as welding the magnetic material  210  to the bobbin assembly  100 , and fashioning a leading edge  212  of the magnetic material  210  such that it can be retained to the split bobbin assembly  100 . For example, the leading edge  212  may be received into a slot (not shown) formed in the bobbin assembly  100  such that the leading edge  212  is captured and retained therein. 
     Referring to FIGS. 2,  8 , and  9 . FIG. 9 shows the final step of an exemplary method of continuous magnetic core winding of electrical transformers in accordance with the present invention. A drive gear  220  is brought into contact with the first flange  108  and the second flange  110 . The drive gear  220  is fitted with gear teeth or other protuberances which engage the first and second flanges  108  and  110  in meshing contact. An idle gear  222  is brought into contact with the first flange  108  and the second flange  110  of the first split bobbin half  102  or said flanges of the second split bobbin half  104  of the bobbin assembly  100 . The drive gear  220  is connected to a rod  224  that is connected to a drive motor  226 . The drive motor  226  applies a torque to the rod  224  thus turning the drive gear  220  and hence turning the bobbin assembly  100  resulting in the winding of the magnetic material  210  about the core bobbin assembly  100 . The idle gear  222  engages the first the second flanges of the bobbin  100  with gear teeth or similar protuberances. The idle gear  222  balances the engaging force of the drive gear  220  as the drive motor  226  winds the magnetic material  210  about the bobbin assembly  100 . The drive motor  226  may be powered by a ‘servo’ type motor so as to accurately control the amount of winding turns required for a chosen magnetic material and for a prescribed radius of the winding member  112 . The magnetic material  210  can be pre-cut to desired dimensions or it may be of continuous length and then severed when a prescribed number of turns of the bobbin assembly  100  are made. A prescribed tension is applied to the magnetic material  210  during the winding process specific to the prescribed magnetic material  210  and/or the particular application of the transformer or inductor. A trailing edge  214  of the magnetic material  210  is secured to the underlying magnetic material  210  by any of a plurality of common adhesive processes. 
     A specific transformer or inductor application may require a plurality of magnetic cores be constructed about the wire coil  200 . FIG. 10 shows a side elevation view of an arrangement of the wound bobbin assembly  100  and a second wound bobbin assembly  300  assembled about the wire coil  200  in accordance with the present invention. The bobbin assembly  300  is installed about the wire coil using the method disclosed herein above. 
     FIG. 11 depicts a side elevation view of an alternative embodiment of the magnetic core and wire coil arrangement assembled in accordance with the present invention. The wire coil  200  is coupled with a second wire coil  250  at an edge  252 . The core bobbin assembly  100  is installed about the interface of the wire coil  200  and the second wire coil  250  at the edge  252 . The core bobbin assembly  100  is installed about the wire coils as discussed herein above by positioning the first bobbin half  102  and then the second bobbin half  104  about the coils and securing them via the locking and alignment assemblies  106 . The magnetic material  210  is wound about the bobbin assembly  100  using the method as described herein above. 
     Another alternative embodiment of the present invention utilizes a standard, non-split core winding bobbin. The magnetic material may be wound about the standard bobbin by using a modified coil winding machine in which the feed mechanism allows magnetic material to be fed instead of the wire feeding instituted by the prior art. The standard bobbin is tooled into a standard winding anvil and the magnetic strip is wound onto said bobbin from the modified feed mechanism. The wound standard bobbin may be used as a receiving member for a split bobbin wire coil assembly in the construction of a transformer or inductor. 
     The bobbin assembly  100  of the present invention may be formed of any suitable material and in one exemplary embodiment, the bobbin assembly  100  is formed of a suitable plastic material. 
     While preferred embodiments have been shown and described, various modification and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is understood that the present invention has been described by way of illustrations and not limitation.