Lead-frame, lead-frame assembly and related methods

Abstract

 A lead-frame is provided which includes a base segment and a plurality of circuit trace segments extending from the base segment. At least one of the circuit trace segments includes a section which bridges over at least an adjacent circuit trace segment. The bridging circuit trace segment includes a first end, and a distal contact segment at an opposite end, which are positioned on opposite sides of the adjacent circuit trace segment. A lead-frame assembly which includes such a lead-frame, and methods of fabricating the lead-frame and lead-frame assembly, are also provided.

Description

TECHNICAL FIELD

[0001] The present invention relates to a lead-frame for use in an electrical connector. More particularly, the present invention relates to such a lead-frame which is useful, without limitation, with an insert molded insulative housing to provide a lead-frame assembly which serves as an electrical connector. A method of forming such a lead-frame and lead-frame assembly is also disclosed.

BACKGROUND ART

[0002] When designing insert molded insulative housings which contain multiple contacts to form an electrical connector, it is often necessary to provide a structure in which all of the circuit traces are in a single plane. As a practical matter, this limitation is necessitated by the preference of manufacturing all of the contacts in a single lead-frame that is stamped in one progressive stamping die. A drawback to such a configuration is that there is less flexibility in the routing of the connection points which provide electrical contact between the electrical connector provided by the insulative housing and the component or system to which the electrical connector is to be connected.

[0003] One known technique to provide more flexibility in the routing of the connection points in insert molded housings is to use multiple stampings. In other words, two or more lead-frames are provided to route the connection points of each insert molded housing. However, this increases the complexity by increasing the number of components which must be loaded into the injection mold. In addition, the complexity of the loading tooling and the cycle time of the process may be adversely affected. Further, additional stamping dies are required. All of the foregoing increases the cost of manufacturing the product.

DISCLOSURE OF THE INVENTION

[0004] It is an object of the present invention to provide an improved lead-frame and a lead-frame assembly containing such an improved lead-frame.

[0005] Another object of the present invention is to provide an improved lead-frame having improved flexibility in the routing of lead-frame connection points.

[0006] It is another object of the present invention to increase the flexibility in the routing of lead-frame connection points in a lead-frame assembly which includes multiple contacts all of which are provided in a single lead-frame.

[0007] It is yet another object of the present invention to increase the flexibility in the routing of lead-frame connection points in a lead-frame assembly which includes multiple contacts all of which are provided in a single lead-frame that is stamped in one progressive stamping die.

[0008] A further object of the present invention is to provide an improved lead-frame having improved flexibility in the routing of lead-frame connection points, and a lead-frame assembly which contains such an improved lead-frame, which is less costly than those manufactured heretofore.

[0009] Yet another object of the present invention is to provide an improved lead-frame assembly having flexibility in the routing of connection points using contacts provided by a single stamping.

[0010] A further object of the present invention is to provide an improved method of fabricating a lead-frame.

[0011] Another object of the present invention is to provide an improved method of fabricating a lead-frame assembly.

[0012] These objects are achieve, in one aspect of the invention, by providing a lead-frame, comprising a base segment and a plurality of circuit trace segments extending from the base segment. Each circuit trace segment extends from a first end adjacent the base segment to an opposite distal contact segment. The distal contact segments are parallel. At least one circuit trace segment includes a section which bridges over at least an adjacent circuit trace segment. The distal contact segment of the bridging circuit trace segment is located on one side of the adjacent circuit trace segment, and the first end of the bridging circuit trace segment is located on an opposite side of the adjacent circuit trace segment. A lead-frame assembly which comprises the foregoing lead-frame is also disclosed. Methods of fabricating the foregoing lead-frame, and lead-frame assembly, are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] This invention may be clearly understood by reference to the attached drawings wherein like parts are designated by like reference numerals and in which:

FIG. 1 is a perspective view of a lead-frame embodying the present invention;

FIG. 2 is a perspective view of a lead-frame assembly, embodying the present invention, aligned for electrical connection to a harness connector;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 2, just prior to electrical connection of the lead-frame assembly to the harness connector;

FIG. 4 is a plane view of a lead-frame blank for use in the fabrication of a lead-frame embodying the present invention;

FIG. 5 is a plane view of the lead-frame blank of FIG. 4 which has been folded to provide a lead-frame similar to the lead-frame of FIG. 1; and

FIG. 6 is a perspective view illustrating conveying apparatus useful in fabricating a lead-frame embodying the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims taken in conjunction with the above-described drawings.

[0015] Referring now to the drawings with greater particularity, in the embodiment of FIG. 1, a lead-frame 10 is provided. Lead-frame 10 includes a base segment and a plurality of circuit trace segments. For example, lead-frame 10 includes a base segment 12 and a plurality of circuit trace segments 14, 16, 18, 20 and 22 extending from the base segment. More or less circuit trace segments may be provided as desired. Each circuit trace segment extends from a first end adjacent the base segment 12 to an opposite end which includes a distal contact segment. For example, circuit trace segment 14 extends from a first end 24 to an opposite end which includes a distal contact segment 26. The distal contact segments are parallel to each other as illustrated in FIG. 1. At least one circuit trace segment includes a section which bridges over at least an adjacent circuit trace segment. For example, in the embodiment illustrated in FIG. 1, the circuit trace segment 16 includes a section 28 which bridges over an adjacent circuit trace segment 18. By "bridges over" is meant that a section of a circuit trace segment is raised above, is out of contact with and crosses over one or more other circuit trace segments. In the embodiment illustrated in FIG. 1, section 28 bridges over the circuit trace segments 18, 20 and 22. The distal end segment 30 of the circuit trace segment 16 is located on one side 32 of the circuit trace segment 18 and the first end 34 of the circuit trace segment 16 is located on an opposite side 36 of the circuit trace segment 18.

[0016] In the embodiment illustrated in FIG. 1, the distal contact segments, such as segments 26 and 30, and the first ends, such as ends 24 and 34, extend in a first plane. With the exception of circuit trace segment 16, all of the circuit trace segments illustrated in FIG. 1 extend substantially continuously in such first plane from respective first ends to respective distal contact segments. For example, circuit trace segment 14 extends substantially continuously in such first plane from the first end 24 to the distal contact segment 26. The section 28 of the circuit trace segment 16 extends in a second plane which is parallel to such first plane as is evident from FIG. 1.

[0017] In the embodiment illustrated in FIG. 1, each circuit trace segment includes a length which extends in a direction 38 which is substantially perpendicular to the base segment 12. For example, all of the first ends, such as first ends 24 and 34, extend in direction 38. Section 28 of the circuit trace segment 16 extends in a direction 40 which is substantially parallel to base segment 12. In one embodiment, all of the distal contact segments are equally spaced, and all of the first ends are parallel to each other but not equally spaced. For example, in the embodiment illustrated in FIG. 1, all of the distal contact segments are equally spaced, each distance 42 between adjacent distal contact segments being substantially equal. Similarly, although all of the first ends are parallel, they are not equally spaced, the distances 44 and 46 being substantially equal to each other but different from the distances 48 and 50 which are different from each other, as illustrated in FIG. 1.

[0018] In one embodiment, at least one of the circuit trace segments includes more than one distal contact segment. For example, in the embodiment illustrated in FIG. 1, circuit trace segment 20 is forked at 52 to provide two distal contact segments 54 and 56.

[0019] The lead-frame of the present invention is useful in the fabrication of a lead-frame assembly of the present invention. For example, FIG. 2 depicts a lead-frame assembly 58 which comprises a lead-frame 10 of the type illustrated in FIG. 1, and a plastic lead-frame insulative housing 60 which may be electrically and mechanically mated with a harness connector 62 in a conventional manner.

[0020] In one embodiment of the present invention, a portion of the lead-frame is embedded within a region of the plastic lead-frame insulative housing. For example, in the embodiment illustrated in FIG. 3, such portion is outlined by the phantom lines 64 and such region is the region 66 within phantom lines 64. In particular, a section of each circuit trace segment 14-22 is embedded in region 66 of the plastic lead-frame insulative housing 60. The section 28 of the circuit trace segment 16 is also embedded in the region 66. Each circuit trace segment includes an exposed distal contact segment such as distal contact segments 26, 54, 56 and 30 which extend in a first direction 68 out of and away from the region 66, the distal contact segments being parallel to one another as illustrated in FIG. 3. Each circuit trace segment 14-22 also includes an exposed end segment 70, 72, 74, 76 and 78 which extends in an opposite second direction 80 out of and away from the region 66 of the plastic lead-frame insulative housing 60.

[0021] The method of fabricating the lead-frame 10 will now be described. In one embodiment, a sheet of conductive material such as a sheet of copper is cut into the desired configuration. For example, a sheet of conductive material may be cut into the configuration depicted in FIG. 4. The cutting is effected such that the base segment 12 and plurality of circuit trace segments 14-22 are provided. Each circuit trace segment is cut so as to extend from a first end adjacent the base segment 12, such as first end 24, to a distal end segment, such as distal end segment 26, of circuit trace segment 14, all but one of the distal end segments being parallel to each other as illustrated in FIG. 4. In this embodiment, the section 28 of the circuit trace segment 16 is substantially perpendicular to the base segment 12. Distal end segment 30 of circuit trace segment 16 will extend in a direction 82 which is substantially perpendicular to the section 28 of circuit trace segment 16 and substantially parallel to the base segment 12. The sheet of conductive material may be cut such that at least one circuit trace segment, such as circuit trace segment 20, includes more than one distal contact segment, such as distal contact segments 54 and 56. In one embodiment, such cutting step may be effected in a conventional stamping operation.

[0022] At least one circuit trace segment is bent or folded until at least a section thereof bridges over at least one adjacent circuit trace segment. For example, as illustrated in FIG. 5, circuit trace segment 16 is bent until the section 28 bridges over the adjacent circuit trace segment 18 and circuit trace segments 20 and 22.

[0023] Due to the configuration of FIG. 4 as discussed above, when the bending operation has been completed the distal end segment 30 will be parallel and adjacent to the distal end segment 84 of circuit trace segment 22. The cutting and bending or folding of the circuit trace segments may be effected in a conventional die and may be effected in a single operation. Cutting may be effected such that each circuit trace segment includes a length which extends in a direction substantially perpendicular to the base segment 12, and bending may be effected such that the section 28 is substantially parallel to the base segment.

[0024] When the cutting and bending is completed, the distal end segment 30 and the first end 34 of the circuit trace segment 16 will be on opposite sides of the circuit trace segment 18. Subsequent to cutting, the cut sheet will extend in a first plane. Subsequent to bending, the section 28 will extend in a second plane parallel to the first plane so that the lead-frame so formed will have the configuration of lead-frame 10 of FIG. 1.

[0025] It will be evident from FIG. 4 that subsequent to the cutting step all of the distal end segments and the opposite ends of the circuit trace segments will not be equally spaced. It will be evident from FIG. 5 that when the bending has been completed, all of the distal end segments will be equally spaced although spacing between the opposite ends will not have changed.

[0026] In one embodiment, the lead-frame may be plated in a conventional manner. For example, the lead-frame 10 depicted in FIG. 5 may be plated to provide an aluminum inlay upon each circuit trace segment 14-22 at a respective length 86.

[0027] The fabrication of lead-frames of the present invention may be accomplished in a continuous process wherein a plurality of lead-frames may be formed from a conductive material and continuously conveyed from one processing step to another. For example, FIG. 6 schematically represents a plurality of lead-frames 10 which were formed from a conductive material in a progressive stamping die and are being carried by a strip forming the base segment 12, the lead-frames travelling from the die (not shown) to rolls 88 and 90 from which the lead-frames progress to a plating operation (not shown).

[0028] The lead-frames of the present invention are useful in the fabrication of the lead-frame assembly of the present invention. For example, the lead-frame insulative housing 60 of FIGS. 2 and 3 may be fabricated in a conventional extrusion molding process. In particular, a lead-frame 10 may be embedded within the plastic lead-frame insulative housing 60 during the extrusion thereof such that the portion of the lead-frame outlined by the phantom lines 64 is embedded in the lead-frame insulative housing at the region 66 within phantom lines 64. In this manner, the section of each circuit trace segment 14-22 within the phantom lines 64 may be embedded within region 66 such that a length of each distal contact segment, such as distal contact segment 26 of circuit trace segment 14, extends from the region 66 in the first direction 68, and at least a length of each first end, such as length 70 extends from region 66 in the second direction 80. A conventional insert injection molding operation may be used to embed the lead-frame in the insulative housing as described herein.

[0029] When the extruding is completed, the lead-frame 10 may be trimmed at each circuit trace segment 14-22 to remove the excess material, including the base segment, identified by phantom line 92, so that only the distal contact segments, such as distal contact segment 26, and the lengths of end segments, such as length 70, are exposed.

[0030] The distal contact segments are prong like male members which are constructed and arranged for insertion into female connectors 94 of the harness connector 62, and the lengths 70 are constructed and arranged for electrical and mechanical connection to some other component(s), as desired, as for example, by welding conductors thereto.

[0031] The folding of the section 28 of the circuit trace segment 16 so that the section 28 bridges over an adjacent circuit trace segment provides multiple routing planes in a single stamping. In essence, a flat pattern or blank is formed such that the circuit traces can be formed and folded over each other in multiple planes thereby increasing routing flexibility in one stamping operation.

[0032] The embodiments which have been described herein are but some of several which utilize this invention and are set forth here by way of illustration but not of limitation. It is apparent that many other embodiments which will be readily apparent to those skilled in the art may be made without departing materially from the spirit and scope of this invention.

Claims

1. A lead-frame, comprising:

a base segment; and

a plurality of circuit trace segments extending from said base segment, each circuit trace segment of said plurality of circuit trace segments extending from a first end adjacent said base segment to an opposite distal contact segment, said distal contact segments being parallel, at least one circuit trace segment including a section which bridges over at least an adjacent of said circuit trace segments, said distal contact segment of said at least one circuit trace segment being located on one side of said adjacent of said circuit trace segments, and said first end of said at least one circuit trace segment being located on an opposite side of said adjacent of said circuit trace segments.

2. The lead-frame of claim 1 wherein said distal contact segments and said first ends extend in a first plane; wherein a plurality of said plurality of circuit trace segments extend substantially continuously in said first plane from said first end to said distal contact segment; and wherein said section of said at least one circuit trace segment extends in a second plane parallel to said first plane.

3. The lead-frame of claim 1 wherein all of said distal contact segments are equally spaced, and wherein all of said first ends are parallel to each other and not equally spaced.

4. The lead-frame of claim 1 wherein each circuit trace segment includes a length which extends in a direction substantially perpendicular to said base segment, and wherein said section of said at least one of said circuit trace segments extends in a direction substantially parallel to said base segment.

5. The lead-frame of claim 1 wherein at least one circuit trace segment includes more than one distal contact segment.

6. A lead-frame assembly, comprising:

a lead-frame insulative housing; and

a lead-frame, a portion of which is embedded within a region of said housing, said lead-frame comprising

a plurality of circuit trace segments a section of each of which is embedded within said region, each circuit trace segment of said plurality of circuit trace segments including an exposed distal contact segment extending in a first direction away from said region, said distal contact segments being parallel, and an exposed end segment extending in an opposite second direction away from said region, at least one circuit trace segment including a section which bridges over at least an adjacent of said circuit trace segments and is embedded in said region, said distal contact segment of said at least one circuit trace segment being located on one side of said adjacent of said circuit trace segments, and said end segment of said at least one circuit trace segment being located on an opposite side of said adjacent of said circuit trace segments.

7. The lead-frame assembly of claim 6 wherein distal contact segments and said first ends extend in a first plane; wherein a plurality of said plurality of circuit trace segments extend substantially continuously in said first plane from said first end to said distal contact segment; and wherein said section of said at least one circuit trace segment extends in a second plane parallel to said first plane.

8. The lead-frame assembly of claim 6 wherein all of said distal contact segments are equally spaced, and wherein all of said first ends are parallel to each other and not equally spaced.

9. The lead-frame assembly of claim 6 wherein each circuit trace segment includes a length which extends in a direction substantially perpendicular to said region, and wherein said section of said at least one of said circuit trace segments extends in a direction substantially parallel to said region.

10. The lead-frame assembly of claim 6 wherein at least one circuit trace segment includes more than one distal contact segment.

11. A method of forming a lead-frame, comprising the steps of:

(a) cutting a sheet of conductive material into the configuration of a base segment and a plurality of circuit trace segments, each circuit trace segment extending from a first end adjacent said base segment to a distal end segment; and

(b) bending at least one circuit trace segment until at least a section of said at least one circuit trace segment bridges over at least one adjacent circuit trace segment.

12. The method of claim 11 wherein said steps (a) and (b) are accomplished in a progressive stamping die and step (c) is accomplished in an insert injection mold.

13. The method of claim 11 wherein said cut sheet extends in a first plane, and wherein step(b) includes bending said at least one circuit trace segment until said section bridges over said at least one adjacent circuit trace segment in a second plane parallel to said first plane.

14. The method of claim 11 wherein step (a) includes cutting said sheet of conductive material such that said distal end segments are not all equally spaced and said first ends are not all equally spaced, and wherein step (b) includes bending said distal end segment until all of said distal end segments are equally spaced.

15. The method of claim 11 wherein step (a) includes cutting said sheet of conductive material such that each circuit trace segment includes a length which extends in a direction substantially perpendicular to said base segment, and wherein step (b) includes bending said at least one circuit trace segment until said section is substantially parallel to said base segment.

16. The method of claim 11 wherein step (a) includes cutting said sheet of conductive material such that at least one circuit trace segment includes more than one distal contact segment.

17. A method of forming a lead-frame assembly, comprising the steps of:

(a) cutting a sheet of conductive material into the configuration of a base segment and a plurality of circuit trace segments, each circuit trace segment extending from a first end adjacent said base segment to a distal end segment;

(b) bending at least one circuit trace segment until at least a section of said at least one circuit trace segment bridges over at least one adjacent circuit trace segment forming a lead-frame;

(c) embedding a section of each circuit trace segment of said plurality of circuit trace segments of said lead-frame in a region of a lead-frame insulative housing such that at least a length of each distal contact segment extends from said region in a first direction and at least a length of each first end extends from said region in a second direction; and

(d) trimming said base segment from each circuit trace segment.

18. A method of claim 17 wherein said steps (a) and (b) are accomplished in a progressive stamping die and step (c) is accomplished in an insert injection mold..

19. A method of claim 17 wherein step (a) includes cutting said sheet of conductive material such that each circuit trace segment includes a length which extends in a direction substantially perpendicular to said base segment, and wherein step (b) includes bending said at least one circuit trace segment until said section is substantially parallel to said base segment.

20. A method of claim 17 wherein step (a) includes cutting said sheet of conductive material such that at least one circuit trace segment includes more than one distal contact segment.

Drawing