Note: Descriptions are shown in the official language in which they were submitted.
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CONNECTOR HAVING FLAT STAMPED CONTACT TERMINALS
This invention relates to multi-contact electrical connectors
and particularly to connectors having receptacle contacts which
are of flat stamped sheet metal.
High quality multi-contact electrical connectors are usually
provided with cylindrical receptacle contacts in the receptacle
portion and cylindrical pins in the plug portion. The pins and
sockets may be either solid screw machine parts or they may be
stamping which have been formed into hollow cylinders as
receptacles or pins.
Electrical contacts can be produced as flat stamping at
considerably lower cost than can cylindrical contacts however,
flat stamped contacts are used to only a limited extent and they
are not ordinarily used for high quality connectors of the pin
and socket type where good electrical performance and a high
degree of reliability are required. The present invention is
directed to the achievement of a multi-contact electrical connector
having flat stamped contacts therein which is capable of
electrical and mechanical performance which is comparable to that
of a high quality pin and socket type connector of the type
currently being used.
An electrical connector in accordance with the invention
comprises an insulating housing having a mating face, a rear
face, and a contact-receiving cavity extending there through from
the rear face to the mating face. A contact terminal is provided
in the cavity, the contact terminal having a mounting portion
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which is proximate to the rear face and a contact arm which is
proximate to the mating face, the contact terminal having been
inserted into the cavity from the rear face. The connector is
characterized in that the contact terminal is a flat stamped sheet
metal member having oppositely facing major rolled surfaces and
having sheared edges, the contact arm being twisted, with respect
to the mounting portion, through an angle of 90 so that the
major surfaces of the arm define planes which extend normally of
the planes defined by the major surfaces of the mounting portion,
the contact arm having side edges which extend along its length
and having a width, as measured between its side edges, which is
substantially greater than the thickness of the contact terminal
as measured between the major surfaces thereof in the mounting
portion, the cavity having a rear portion which extends inwardly
from the rear face and a forward portion which extends inwardly
from the mating face, the mounting portion of the terminal being
in the rear portion and the contact arm being in the forward port
lion, the cavity having opposed sidewalls and opposed endless,
the major surfaces of the mounting portion being substantially
parallel to the sidewalls, the distance between the sidewalls being
greater than the width of the contact arm and substantially greater
than the thickness of the mounting portion, the opposed endless
each have two converging surfaces extending from the sidewalls
and which intersect to form a V-notch, the V-notches constituting
edge-receiving grooves extending from the rear face towards the
forward portion of the cavity, the sheared edges of the mounting
portion having an interference fit in the grooves.
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In accordance with a further embodiment a first pair
of stabilizing projections extend laterally of the axis of the
terminal at a location adjacent to the contact arm and a second
pair of stabilizing projections extend laterally of the axis at a
location spaced from the contact arm. the second pair of project
lions extend laterally a greater distance than the first pair of
projections whereby during insertion of the terminal into the
cavity, the first pair of projections gouge into the grooves and
enlarge the grooves, and the second pair of projections also
gouge into the grooves, and when the terminal is fully inserted,
the mounting portion will be held in the cavity by the projections
of both pairs.
According to another broad aspect, the invention pro-
vises an electrical connector of the type comprising an insulate
in housing having a cantact-receiving face, a contact-receiving
cavity extending into the housing from the contact-receiving face,
and a contact terminal in the cavity, the contact terminal having
been inserted into the cavity from the contact-receiving face, the
connector being characterized in that: the contact terminal is a
flat stamped sheet metal member having oppositely facing major
rolled surfaces and oppositely facing side edges, the cavity
having opposed sidewalls and opposed endless, the oppositely lag-
in major surfaces of the terminal being parallel to the sidewalls,
the sidewalls being spaced-apart by a distance substantially
greater than the thickness of the terminal as measured between the
major surfaces, the opposed endless each have two converging
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surfaces which intersect to form a V-notch which extends inwardly
from the contact-receiving face, the side edges of the contact
terminal being centered in the roots of the V-notches.
The invention will now be described in greater detail
with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of a connector in
accordance with the invention exploded from the surface of a
circuit board and showing a contact terminal exploded from the
connector.
Figure 2 is a cross sectional view taken along the
lines 1-1 of Figure 1 but showing the connector assembled to the
circuit board.
Figure 3 is a plan view of a short section of contact
terminals in accordance with the invention.
Figure 4 is a view taken along the lines 4-4 of
Figure 1.
Figure 5 is a view taken along the lines 5-5 of
Figure 4.
Figure 6 is a view looking in the direction of the
arrows 6-6 of Figure 2.
Figure 7 is a view similar to Figure 6 which thus-
trades the self-centering of a contact terminal during insertion
into a cavity.
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Figure 8 is a perspective view of a core pin used in the
molding of a cavity housing in accordance with the invention.
Figures 1 and 2 show a connector 2 in accordance with the
invention which serves to connect compact pins in a
complimentary connector to conductors 4 on the lower surface 7
of a circuit board 8. The connector 2 comprises an insulating
housing 10 having a mating face 12, a rear face I and cavities
16 which extend through the housing from the mating face to the
rear face. The housing is of molded insulating material,
l o preferably a thermoplastic which can be deformed slightly when
the terminals are inserted in the cavities as will be described
below .
The housing has integral ears 20 by means of which it is
secured to the surface of the circuit board 8, fasteners 22 being
provided for this purpose as indicated. The forward portion of
the housing has a trapezoidal projection 24 and the mating face
12 is the face of this projection. The connector shown also has
sheet metal shielding 26 surrounding the forward portions of the
housing .
The contact terminals 18 are produced in continuous strip
form with each of the terminals being connected to a carrier
strip 27, see Figure 3. The terminals are produced as flat
stamping having an enlarged central mounting portion 28, an
integral solder post portion, and at least one contact arm. The
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enlarged mounting portion 28 has oppositely facing major
surfaces 30, 32 (Figure 6) which were the rolled surfaces of the
strip stock metal from which the terminal was stamped. The
mounting portion has upper and lower side edges 34, 36 which
are sheared edges and which have a width equal to the thickness
of the stock metal.
The first pair of retaining projections 38 are provided on
the mounting portion adjacent to the left-hand end of this
portion of the terminal and these projections 38 extend slightly
beyond the adjacent edge portions. A second pair of projections
40 are provided rightwardly of the projections 38 as viewed in
Figure 3 and the projections 40 extend slightly beyond the
projections 38. These projections assist in retaining the terminal
in the cavity as will be explained below.
The mounting portion has a rearward edge 42 and a
centrally extending post 44 which is twisted as shown in Figure
1 when the terminal is inserted into the housing and the housing
is assembled to the circuit board as shown in Figure 2. The
post may be soldered to the conductor as shown at 46.
A pair of contact arms 48 extend from the left-hand end, as
viewed in the drawing, of the mounting portion 28 and these
arms are twisted in opposite directions through an angle of
substantially 90 as shown at 50 at a location adjacent to the
mounting portion. The arms thus have opposed rolled surfaces
and a contact zone as shown at 51 is provided on each arm by
bending the end portion of the arm as shown at 52. The width
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of the contact zone is the distance between the side edges 49 of
the arms as shown in Figure 3. Advantageously, the contact
zones 51 are plated with a contact metal, such as gold, and this
plating operation can be carried out when the terminals are in
5 strip form. The gold plating can therefore be provided only in
the contact zone of the contact arms thereby reducing the
plating costs for the terminal.
Each of the cavities 16 has a rear portion 56 which receives
the mounting portion 28 of the terminal and a forward portion 58
10 which receives the contact arms of the terminal. Each cavity
has opposed sidewalls 60 we itch extend from the rear face 14
substantially to the inner end 72 of the cavity which is adjacent
face 12. These sidewalls are substantially parallel but are
tapered very slightly towards each other in accordance with good
15 molding practice. Inclined lead in surfaces 61 are provided on
the sidewalls adjacent to the rear face 14 to guide the terminals
into the cavities.
Each cavity has opposed end walls, the endless having
rearward portions 62 and forward portions 70, see Figure 5. In
20 the rearward portion 62 of the cavity, the endless 62 have
convergent surfaces 64 which extend from the sidewalls obliquely
towards each other and which intersect to form a groove in the
form of a V-notch 66. This V-notch extends to a triangular
ramp 68 in each of the endless and the endless in the forward
25 portion of the cavity are again substantially parallel to each
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other as shown at 70 in Figure 2. A circular opening 74 is
provided in the inner end 72 of the cavity which extends to the
mating face 12, this opening merging with a conical surface 76
which serves as a guide surface when a pin is inserted into the
5 opening. The terminals 18 are inserted into the cavities from
the rear face 14 (the contact receiving face). This oration is
carried out with a contact terminal insertion machine.
The twisting of the contact arms provides a flat rolled
surface for the contact surfaces 51 of the arms rather than a
10 sheared edge surface as noted above. Also, the contact arms
can be relatively wide, significantly wider than the thickness
of the metal stock from which the terminal was stamped.
Because of the width of the contact arms 48, as measured
between their side edges, the cavity 16 must be of sufficient
15 width as measured between the sidewalls 60, in its rearward
portion to permit insertion of the arms there through until the
terminal is fully inserted. This means that the relatively thin
mounting portion 28 must be supported in the relatively wide
rearward portion of the cavity. Good support for the terminal
20 is obtained by virtue of the provision of the V-notches 66 and
the projections 38, 40 on the mounting portion of the terminal.
As the terminal is inserted, the leading projections 38 gouge into
the V-notch very slightly and form a furrow. As insertion
continues, the second projections 40 gouge into the previously
25 formed furrow by a slight additional amount and when the
terminal comes to rest, the mounting portion will be held by
interference fits in the vicinity of all four projections 38, 40,
If the material is a thermoplastic which is capable of some flow,
it will tend to flow around the surfaces 30, 32 in the vicinity of
5 the projections 38, 40 and the terminal will be firmly held in the
cavity .
A further distinct advantage of the form of cavity shown is
that during insertion of a terminal into a cavity, it is impossible
to align the edges 34, 36 perfectly with the V-notches 66 in the
10 endless. However, during the initial stages of insertion and
when the projections 38 engage the surface adjacent to the
opposed V-notches, the terminal will be slightly reoriented and
will find its own center line in the cavity. In other words, the
form of the cavity compensates for any slight misalignment of the
15 terminal when insertion is carried out. As a result, the terminal
will be precisely located in the cavity in the completed
connector. Figure 7 shows a slightly misaligned terminal at the
beginning of the terminal inserting operation. As insertion
proceeds, the projections will slide over the inclined surfaces 64
20 until they are sealed in the V-notches 66 in the endless.
Figure 8 shows the core pin used to produce cavities in the
connector, the surfaces of the core pin being identified by the
same reference numerals, differentiated by prime marks, as are
used in the foregoing description of the cavity. It will be noted
25 that the core pin has pilaster-like projections 78' centrally
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located on its surfaces 60'. These projections are merely
- provided for the purpose of strengthening the core pin and they
produce the recesses 78 in the cavity shown in Figure 5.
Terminals in accordance with the invention can be produced
5 in any desired size and in fact can be manufactured in sizes
which are comparable to the sizes of the smallest conventional
pin and socket terminals. For example, one embodiment of a
terminal in accordance with the invention has an overall length
from the tip of the contact arms to the right-hand edge of the
10 mounting portion of the 9. 76 mm . The arms have a width of
0.62 mm which is substantially twice the thickness of the
mounting portion which is 0 . 32 mm .
Connectors in accordance wit to the invention can be used in
place of connectors having conventional cylindrical sockets
15 which are more expensive to manufacture than the flat stamped
terminals 18. The terminals 18 can be inserted into the cavities
by an automatic insertion machine at a very fast rate and the
terminals will be properly located by virtue of the self-aligning
feature illustrated in Figures 7 and 6.
