Note: Descriptions are shown in the official language in which they were submitted.
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AE 38~ PATENT
APPARATUS AND METHOD FOR ELECTRICAL CONNECTION
I Field of the Invention
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
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 elongatebody of electrically conductive material so shaped in manufacture
as to define apices, one being identified as 10a, with flat surface
expanses extending between ad~acent 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.
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 dimensionin~ 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
2121~48
1 least, the securement of components attendant on the apex-eyelet
engagement assures readiness for attendant solder-assisted
electrical connection.
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,~96, No. 4,557,539 and No.
5,002,507.
From applicant's viewpoint, the Fig. l 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
The present invention has ~s 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.
Another object of the invention is the provision of
improved methods for solid cross-section terminal pin formation.
In the attainment o~ the Poregoing and other objects, the
invention provides, in one aspact, 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
dista] 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.
2~2~5~ ~
,
1 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.
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.
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 ~orce
of the formed starting member in the first component through-
aperture than would exist in the absence of such cross-sectional
modi~ication.
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 de~ining an exterior apex complemental to the socket
interiorly configured apex. The modifying step is practiced in
part by modi~ying the starting member as so ~ormed 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.
,:
2~2~
1 The modifying step is desirably practiced so as to provide
contiguity between the exterior apex and the arcuate surface.
In the preferential method of the invention, the forming
step is ~o 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.
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
Fig. l 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.
Fig. 2 is a bottom plan of view of the Fig. l prior art
arrangement.
Fig. 3 is a front elevation of a terminal pin in
accordance with the present invention.
Fig. ~ is a view of the terminal pin of Fig. 3 ~s would
be seen from plane IV-IV of Fig. 3, with sectioning omitted.
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.
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.
~ ig. 7 is a partial bottom plan of view of the Fig. 6
arrangement.
Fig. 8 is a front elevation showing of a portion of a
further embodiment of a terminal pin of the present invention.
Figs. 9 and lO are sectional views of the pin of Fig. 8
taken through the lines IX-IX and X-X, respectively.
2 1 ~
1 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
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 bod~ one end and exhibiting a
longitudinally e~tending 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.
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.
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 1~ 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.
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1 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 con~iguration.
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.
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
lS 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.
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.
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.
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1 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.
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.
Finally, a full connection assembly encompasses PCB 14,
header 14, socket S having interior apex S-l and terminal pin 18.
Here, first body portion 18a is resident in both the header and
socXet and second body portion 18b is resident in the PCB through-
aperture.
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.
Referring to Fig. 8, terminal pin 118 includes a header-
resident (Fig 6) first end extent 118a at the upper portion thereofand 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 ~nd 118b.
Central extent 118c includes a first bent extent 118C-l,
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-l and bulges outwardly to the left.
Thei 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.
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.
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1 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.
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.
Various changes to the foregoing described and shown
structures would now be evident to those skilled in the art.
Accordingly, the particularly disclosecl scope of the invention is
set forth in the following claims.
.
