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(11) | EP 0 621 657 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Apparatus and method for electrical connection |
| (57) A terminal pin (18) for electrical connection, comprises an elongate body constituted
of electrically conductive material in solid cross-section throughout the length of
the body, the body having a first portion (18a) extending from adjacent one end of
the body longitudinally to a location distal from an opposite end of the body and
exhibiting at least one longitudinally extending marginal part defining an apex, the
body having a second portion (18b) extending from adjacent the body opposite end to
a location distal from the body one end and exhibiting a longitudinally extending
marginal part defining an arcuate surface in alignment with the apex of the body member
first portion. |
Field of the Invention
[0001] This invention relates generally to electrical connectors and pertains more particularly to improvements in apparatus and methods for interconnection of headers and like electrical components to other electrical components, such as printed circuit boards.
Background of the Invention
[0002] Referring to Figs. 1 and 2, a currently widespread connection arrangement encompasses a so-called "square cross-section" electrical terminal pin 10, in the form of an elongate body of electrically conductive material so shaped in manufacture as to define apices, one being identified as 10a, with flat surface expanses extending between adjacent apices, one such flat surface expanse being identified as 10b. The square cross-sectional configuration of terminal pin 10 is dictated by the interior configuration of a socket intended for receipt of the terminal pin and electrical connection therewith. Terminal pin 10 is typically provided in a plurality, arranged in one or more rows having a given number of terminal pins. It is customary to mold a plastic body, such as a header, partly indicated at 12 in section, as molded about the terminal pin plurality which is maintained in desired position in the course of the molding operation.
[0003] It is customary to seat the header on a printed circuit board (PCB), partly indicated at 14 in section, such that the terminal pins 10 come into electrical engagement electrically conductive eyelets 16, having portions 16a which are centrally apertured to receive the terminal pins. In present commercial practice, terminal pins 10 are configured throughout the longitudinal extent thereof, excepting conical end sections 10c and 10d, fully in square cross-section. The dimensioning of the terminal pins between apices at one hundred and eighty degrees, i.e., apex 10a and its rearward counterpart in Fig. 1, is selected to be in excess of the interior diameter of eyelet portions 16a. The connection attained thus involves entry of the apices into matter of the eyelets, giving rise desirably to airtight electrical connection and retentive force maintaining the connection. At the least, the securement of components attendant on the apex-eyelet engagement assures readiness for attendant solder-assisted electrical connection.
[0004] The connector industry has otherwise addressed the insertion force problem, i.e., by looking to terminal pins specially fabricated not in solid cross-section throughout, such as "compliant" terminal pins. Examples of this approach are seen in U.S. Patents No. 4,857,019, No. 4,889,496, No. 4,557,539 and No. 5,002,507.
[0005] From applicant's viewpoint, the Fig. 1 prior art approach is ineffective in not at all accommodating lessening of insertion forces. The approaches of the compliant pin are seen as addressing the insertion force problem, however, through specialized terminal pin formation and not accommodating the desired use of a simple, solid cross-section terminal pin, i.e., one exhibiting cross-sectional, transversal continuity as respects forming material lengthwise of the terminal pin.
Summary of the Invention
[0006] The present invention has as its primary object the provision of a simplified terminal pin for header and PCB interconnection with lessened insertion force although of solid cross-section throughout.
[0007] Another object of the invention is the provision of improved methods for solid cross-section terminal pin formation.
[0008] In the attainment of the foregoing and other objects, the invention provides, in one aspect, a terminal pin for electrical connection, comprising an elongate body constituted of electrically conductive material in solid cross-section throughout the length of the body, the body having a first portion, extending from adjacent one end of the body longitudinally to a location distal from an opposite end of the body and exhibiting at least one longitudinally extending marginal part defining an apex, the body having a second portion extending from adjacent the body opposite end to a location distal from the body one end and exhibiting a longitudinally extending marginal part defining an arcuate surface in alignment with the apex of the body member first portion. The first and second body portions are preferably contiguous.
[0009] In a particularly preferred embodiment, the terminal pin body first portion is of square cross-section transversely thereof and defines four such apices, the body second portion defining four such arcuate surfaces each in alignment with a respective one of the four apices, each of the four arcuate surfaces being desirably contiguous with a respective one of the four apices. The body second portion further desirably defines flat surface extents extending between the arcuate surfaces.
[0010] In a further embodiment, the terminal pin body may include a central bent extent between two opposed end extents. The central bent extent includes a generally square cross-section with four arcuate apices.
[0011] In its aspect of providing a method of making a terminal pin for electrical connection between a first electrical component having a through-aperture bounded by electrically conductive material and a second electrical component having a socket of a predetermined interior configuration, the invention looks to the steps of forming an elongate starting member, throughout of electrically conductive material and solid transverse cross-section, with the cross-section complemental to the socket predetermined interior configuration, selecting a portion of the elongate starting member for residence in the first electrical component through-aperture, and modifying the selected portion of the elongate starting member to exhibit a cross-section diverse from the cross-section complemental to the socket predetermined interior configuration and of character lessening insertion force of the formed starting member in the first component through-aperture than would exist in the absence of such cross-sectional modification.
[0012] The socket predetermined interior configuration includes at least one interiorly configured apex and the forming step is practiced in part by forming the starting member throughout its length to exhibit at least one longitudinally extending marginal part defining an exterior apex complemental to the socket interiorly configured apex. The modifying step is practiced in part by modifying the starting member as so formed over the portion thereof selected for residence in the first electrical component through-aperture to exhibit a longitudinally extending exterior defining an arcuate surface in alignment with the exterior apex. The modifying step is desirably practiced so as to provide contiguity between the exterior apex and the arcuate surface.
[0013] In the preferential method of the invention, the forming step is so practiced as to form the starting member with a square cross-section transversely thereof and to define four such exterior apices, and wherein the modifying step is so practiced as to modify the portion of the starting member selected for residence in the first electrical component through-aperture to exhibit four such arcuate surfaces each in alignment with a respective one of the four apices.
[0014] As will be seen from discussion below, the invention has further aspects, respectively in the provision of combinations of terminal pin and header, terminal pin and PCB, of terminal pin, header and PCB, and of terminal pin, header, PCB and socket.
Description of the Drawings
[0015] Fig. 1 is a front elevation, in central section, of a part of a prior art arrangement for interconnection of a header and a PCB, more particularly for interconnection of a header terminal pins and a PCB eyelet.
[0018] Fig. 4 is a view of the terminal pin of Fig. 3 as would be seen from plane IV-IV of Fig. 3, with sectioning omitted.
[0019] Fig. 5 is a view of the terminal pin of Fig. 3 as would be seen from plane V-V of Fig. 3, with sectioning omitted.
[0020] Fig. 6 is a front elevation, in central section, of an arrangement in accordance with the present invention for interconnection of a header and a PCB, more particularly for interconnection of header terminal pins and PCB eyelets.
[0022] Fig. 8 is a front elevation showing of a portion of a further embodiment of a terminal pin of the present invention.
[0023] Figs. 9 and 10 are sectional views of the pin of Fig. 8 taken through the lines IX-IX and X-X, respectively.
[0024] Fig. 11 is a sectional view of the terminal pin of Fig. 8 supported within a printed circuit board through-aperture.
Description of Preferred Embodiments and Practices
[0025] Referring to Figs. 3-5, terminal pin 18 comprises an elongate body constituted of electrically conductive material in solid cross-section throughout the length of the body. The body has a first portion 18a, extending from adjacent one end of the body longitudinally to a location distal from an opposite end of the body and exhibiting at least one longitudinally extending marginal part 18a-1 defining an apex. The body has a second portion 18b, extending from adjacent the body opposite end to a location distal from the body one end and exhibiting a longitudinally extending marginal part 18b-1 defining an arcuate surface in alignment with the apex 18a-1 of the body member first portion 18a. Body portions 18a and 18b are preferably contiguous, i.e., as illustrated, the lowermost end of apex 18a-1 meets the uppermost end of arcuate surface 18b-1.
[0026] Body first portion 18a is of square cross-section transversely thereof and defines four such apices, as is seen particularly in Fig. 4. Body second portion 18b defines four such arcuate surfaces each in alignment with a respective one of the four apices, as is seen particularly in Fig. 5, each of the four arcuate surfaces being contiguous with a respective one of the four apices of body portion 18a. Flat surface extents 18a-2 and 18b-2 extend between the apices and arcuate surfaces of body portions 18a and 18b. The body includes first and second conical terminations 18c and 18d, respectively adjacent the one and opposite ends thereof, body portion 18a being contiguous with first conical termination 18c and second body portion 18b being contiguous with second conical termination 18d.
[0027] A method of making terminal pin 18 looks, at its outset, at the desired electrical connection between a first electrical component having a through-aperture bounded by electrically conductive material, such as PCB 14 of Fig. 1, and a second electrical component, such as header 12 of Fig. 1, whose terminal pins must mate each with a socket of a predetermined interior configuration, e.g., square in cross-section.
[0028] A forming step is first practiced, wherein one forms an elongate starting member, throughout of electrically conductive material and solid transverse cross-section, with the cross-section complemental to the socket predetermined interior configuration. A second step is selecting a portion of the elongate starting member for residence in the first electrical component through-aperture. Here, the invention pre-identifies the measure D1 of Fig. 1, which corresponds to the extent of a terminal pin to be resident in PCB eyelet 16.
[0029] The method involves the further step of modifying the selected portion of the elongate starting member to exhibit a cross-section diverse from the cross-section complemental to the socket predetermined interior configuration and of character lessening insertion force of the formed starting member in the first component through-aperture than would exist in the absence of such cross-sectional modification. This step is realized by rendering second portion 18b of terminal pin 18 of Fig. 3 with the configuration of Fig. 5. The length of second portion 18b is thus selected to be of measure D2, equal to or greater than measure D1.
[0030] While the illustration of the drawings is specific to the square pin cross-section, the method, more generally looks to pin cross-sections complemental to a socket predetermined interior configuration including at least one interiorly configured apex and the forming step is practiced in part by forming the starting member throughout its length to exhibit at least one longitudinally extending marginal part defining an exterior apex complemental to the socket interiorly configured apex. In such context, the modifying step is practiced in part by modifying the starting member as so formed over the portion thereof selected for residence in the first electrical component through-aperture to exhibit a longitudinally extending exterior defining an arcuate surface in alignment with the exterior apex. The modifying step is also desirably practiced so as to provide contiguity between the exterior apex and the arcuate surface.
[0031] Turning to Figs. 6 and 7, assemblies reached per the invention include a first subassembly of PCB 14 and terminal pin 18, wherein second body portion 18b is resident in the printed circuit board through-aperture and first body portion 18a is situated exteriorly of the PCB.
[0032] A further subassembly is that of header 12 and terminal pin 18, wherein first body portion 18a is resident in header 12 and second body portion 18b is situated exteriorly of the header.
[0033] A still further subassembly or assembly is that of PCB 14, header 12 and terminal pin 18, wherein first body portion 18a is resident in the header and second body portion 18b is resident in the PCB through-aperture.
[0034] Finally, a full connection assembly encompasses PCB 14, header 14, socket S having interior apex S-1 and terminal pin 18. Here, first body portion 18a is resident in both the header and socket and second body portion 18b is resident in the PCB through-aperture.
[0035] A further embodiment of the terminal pin of the present invention may be seen in Figs. 8 - 11. The present invention contemplates that the PCB resident portion of the terminal pin may define a crimp or a bend in a manner such is known in the art as exampled by the AMP "Diplomate" connector, commercialized in 1983 - 1985.
[0036] Referring to Fig. 8, terminal pin 118 includes a header-resident (Fig 6) first end extent 118a at the upper portion thereof and an opposed second end extent 118b at the lower end thereof. A central PCB resident extent 118c extends between first extent 118a and second extent 118b. First extent 118a and second extent 118b are generally vertically aligned. Central extent 118c is configured to have a bend or crimp, thereby defining a tortuous path between opposed end extents 118a and 118b.
[0037] Central extent 118c includes a first bent extent 118C-1, which as shown in Fig. 8, bends or bulges outwardly to the right. Central extent 118c includes a second bent extent 118C-2, which is continuous with extent 118C-1 and bulges outwardly to the left. The terminal pin 118 thus is configured to have a transverse expanse t which is wider than the cross-sectional thickness of terminal pin 118. As is known in the art, this assists in retaining the pin in the through-aperture of a printed circuit board as will be described in further detail hereinbelow.
[0038] The central extent 118c of terminal pin 118 is constructed to have a generally square cross-section with the apices thereof defining four arcuate surfaces in the manner described above with respect to Fig. 5.
[0039] As shown in Figs. 9 and 10, as the transverse expanse t of terminal pin 118 is wider than the horizontal cross-section of the pin, an increase in a retentive engagement will be encountered between the terminal pin 118 and the through-aperture 120 of PCB 122 (Fig. 11). This additional resistance helps retain the terminal pins in through-aperture 120 prior to soldering. While providing for increased retentive engagement, the curved apices of the present invention assists in permitting the passage of central extent 118c through the through-aperture 120 of PCB 122.
[0040] As shown in Fig. 11, central extent 118c resides within through-aperture 120 of PCB 122. Its entry being facilitated by the curved apices of central extent 118c. The crimped extent 118c provides for securement of the terminal pin within the through-aperture of the printed circuit board for later solder connection, as is known in the art. Further, the numbers and locations of such PCB resident crimped extents may be a number only as sufficient to provide such temporary securement prior to soldering. The crimped extents may be arranged in balanced fashion among terminal pin rows to provide proper securement.
1. A terminal pin for electrical connection, comprising an elongate body constituted
of electrically conductive material in solid cross-section throughout the length of
the body, said body having a first portion, extending from adjacent one end of said
body longitudinally to a location distal from an opposite end of said body and exhibiting
at least one longitudinally extending marginal part defining an apex, said body having
a second portion extending from adjacent said body opposite end to a location distal
from said body one end and exhibiting a longitudinally extending marginal part defining
an arcuate surface in alignment with said apex of said body member first portion.
2. The terminal pin claimed in claim 1 wherein said first and second body portions are
contiguous.
3. The terminal pin claimed in claim 1 or claim 2 wherein said body first portion is
of square cross-section transversely thereof and defines four such apices, said body
second portion defining four such arcuate surfaces each in alignment with a respective
one of said four apices.
4. The terminal pin claimed in claim 3 wherein each of said four arcuate surfaces is
contiguous with a respective one of said four apices.
5. The terminal pin claimed in claim 3 or claim 4 wherein said body second portion defines
flat surface extends extending between said arcuate surfaces.
6. The terminal pin claimed in any one of claims 1 to 5 wherein said body includes first
and second conical terminations respectively adjacent said one and opposite ends thereof,
said first body portion being contiguous with said first conical termination and said
second body portion being contiguous with said second conical termination.
7. A printed circuit board defining a through-aperture and a terminal pin as claimed
in any one of claims 1 to 6 for electrical connection, said second body portion of
the terminal pin being resident in said printed circuit board through-aperture, said
first body portion of the terminal pin being situate exteriorly of said printed circuit
board.
8. A header and a terminal pin as claimed in any one of claims 1 to 6 for electrical
connection, said first body portion of the terminal being resident in said header,
said second body portion of the terminal being situate exteriorly of said header.
9. A header, a printed circuit board defining a through-aperture and a terminal pin as
claimed in any one of claims 1 to 6 for electrical connection, said first body portion
of the terminal being resident in said header, said second body portion of the terminal
being resident in said printed circuit board through-aperture.
10. A header, a printed circuit board defining a through-aperture, and a terminal pin
as claimed in any one of claims 1 to 6 for electrical connection, and a connector
defining at least one socket defining a longitudinally extending marginal part defining
an interior apex complemental to said body first portion apex of the terminal, said
first body portion of the terminal being resident in both said header and said socket,
said second body portion of the terminal being resident in said printed circuit board
through-aperture.