[0001] This invention relates to a single-piece stamped and formed electrical receptacle
terminal.
[0002] In many applications in the electrical industry it is a continuous requirement to
provide more cost-effective yet more compact, sturdy and reliable electrical terminals.
It is common to find electrical terminals stamped and formed from sheet metal that
have a connection section such as a crimp barrel for connection to a conducting wire,
further comprising a contact section for connection to a complementary terminal, and
means for securing the terminal within the cavity of a connector housing. It is common
to find receptacle terminals for mating with tab or pin terminals to have resilient
cantilever beam contact arms extending from opposed sides of the terminal to receive
the complementary pin or tab therebetween. In certain applications, an additional
outer spring body stamped and formed from a stronger material such as stainless steel
is positioned around the contact section of the terminal and serves to provide means
for securing the terminal within the connector housing and extra spring support for
increasing the spring strength of the inner contact arms. Such an outer spring body
often has the effect of protecting the inner contact area thus making the receptacle
terminal more robust, but also increases the contact pressure and provides a stronger
support for securing of the terminal in a connector housing.
[0003] A two part terminal is however costly to produce, in comparison to a one-piece terminal,
for example as shown in U.S. 4,148,547. The latter terminal does not however have
an outer cage that is robust because side and tops walls are separate from each other.
Furthermore the outer cage side walls require a long strip of sheet metal leading
to a lot of material waste. A single piece terminal with a more robust outer cage
is shown in European patent EP 125927B where cantilever beam contact arms are folded
into the cage from the top wall seam. Here also, there is high material wastage because
the width of the layout of the crimping barrel is much less than the cage and contact
arm section.
[0004] A terminal according to French patent application 2 751 793 overcomes certain of
the aforementioned problems by reducing material usage and providing a well protected
inner receptacle contact section in a single piece design. The cantilever beam contact
arms are protected from the effects of false insertion of a mating pin terminal by
provision of a front wall that guides and locates a mating pin terminal during insertion
into the receptacle terminal. The front wall also serves to provide inwardly stamped
extensions or tabs against which the cantilever beam contact arms resiliently abut
in order to pre-stress the contact arms thereby increasing the contact force against
a mating terminal. The terminal described in this reference also has the advantage
of being easily inserted through a seal without damaging the seal. Despite these improvements,
it would be desirable to further improve single piece receptacle terminals, particularly
in view of reducing material usage and scrap, without compromising robustness and
electrical contact properties. It would be further desirable to provide a particularly
compact single piece electrical terminal with a well protected contact area. It would
be further advantageous to ensure that such terminals can be securely retained in
connector housings.
[0005] It is therefore an object of this invention to provide an improved single piece stamped
and formed electrical receptacle terminal.
[0006] Objects of this invention have been achieved by providing the receptacle terminal
according to claim 1. Disclosed herein is a single piece electrical receptacle terminal
for mating with a complementary tab or pin terminal, the terminal stamped and formed
from sheet metal and comprising a connection section and a contact section comprising
a contact body with top, side and bottom walls forming a box-shape defining an inner
cavity area for receiving the mating terminal therein, the contact section further
comprising cantilever beam contact arms extending from the opposed side walls and
having contact portions arranged proximate a mating end wall at a mating end of the
terminal, the mating end wall provided with a cutout for guiding and locating the
mating tab or pin terminal into the inner cavity area and between the contact arms,
wherein the side walls comprise mating end portions attached and extending from opposed
side edges of the mating end wall and folded substantially orthogonally therefrom
in order to be arranged along sides of the contact section, the side wall mating end
portions comprising locking shoulders for locking the terminals in a connector housing,
the locking shoulders positioned approximately over the contact portion of the contact
arms.
[0007] Advantageously therefore, the layout of sheet metal from which the single piece electrical
terminal is formed is compact thereby requiring little material usage and scrap, in
view of provision of the mating wall side portions extending from side edges of the
mating end wall. Nevertheless, a compact and well protected contact area is provided
by extension of the mating end side wall portions to the region of the contact arm
contact portions. Secure and reliable locking of the terminals within connector housings
is ensured in a simple manner by the locking shoulders provided on the mating end
side wall portions.
[0008] The mating end side wall portions may be secured to the top or bottom walls by welding,
for example laser welding, in order to provide a compact yet rigid mating end portion
of the contact section. In order to further rigidify the box-shape mating end portion
of the contact section, the top or bottom walls and the mating end side wall portions
may be provided with interleaving extensions projecting transverse to the terminal
mating direction. The interleaving extensions thus also securely hold the mating end
wall of the terminal to the top, bottom and side walls. The mating end wall may be
folded from the bottom wall substantially orthogonally thereto whereby the interleaving
extensions of the mating end side wall portions co-operate with complementary extensions
provided on the top wall.
[0009] The connection end of the contact section may be provided with a connection end wall,
for example folded substantially orthogonally from the top wall, in order to prevent
material or objects from flowing or being inserted into the inner cavity area from
a rear end of the terminal, thereby further protecting the contact arms. The connection
end wall may also assist in rigidifying the box-shape of the contact section.
[0010] A connection end of the side walls may be further provided with secondary locking
extensions having locking shoulders provided over a transition portion of the contact
that interconnects the contact and connection sections, the transition portion having
a width narrower than the contact section side walls such that space is provided for
engagement of secondary locking shoulders of a connector housing behind the secondary
locking extensions.
[0011] Further advantageous features of this invention will be set forth in the claims,
or will be apparent from the following description and drawings.
[0012] An embodiment of this invention will now be described by way of example with reference
to the figures in which;
Figure 1 is perspective view of a terminal according to this invention;
Figure 2 is a top view of the terminal according to figure 1 with the top wall removed;
Figure 3 is a perspective view of a stamped layout of a contact section of the terminal;
Figures 4, 5 and 6 are perspective views showing respectively successive stamping
and forming steps of the contact section from the layout of figure 4;
Figure 7 is a perspective view of the contact section of the terminal.
[0013] Referring to the figures, an electrical receptacle terminal 2 comprises a connection
section 4 in the form of a crimping barrel for connection to a wire, and a contact
section 6 attached to the connection section 4 via a transition section 8. The terminal
2 is stamped and formed from sheet metal, for example as illustrated in figures 3-6,
as a single piece terminal. The contact section 6 comprises a bottom wall 10, opposed
side walls 12 extending substantially orthogonally from side edges 13 of the bottom
wall, and a top wall 14 facing the bottom wall 10. The top, side and bottom walls
form a box-shaped receptacle defining an inner cavity area 16 receiving a mating tab
or pin contact section of a complementary terminal (not shown). The contact section
6 is further provided with a front or mating end wall 18 and a rear or connection
end wall 20 positioned respectively at the mating end and connection end of the contact
section 6. The mating end and connection end walls 18, 20 extend approximately perpendicularly
to the insertion direction (I) of a mating pin terminal.
[0014] The mating end wall 18 is attached to and extends from the bottom wall 10 and is
bent substantially 90° from the bottom wall as best seen when comparing figures 5
and 6. The mating end wall 18 is further provided with a cutout 20 as best seen in
figures 5 or 6, formed by inwardly stamping extensions or ledges 22 (see figures 2
or 5) that project roughly in the insertion direction (I).
[0015] The contact section is further provided with a pair of opposed cantilever beam contact
arms 24 extending from an attachment portion 26 proximate the connection section 4
to free ends 28 proximate the mating end wall 18. The contact arms 24 are integrally
connected with the side walls 12 at the attachment portion 26 and converge into the
inner cavity area 16 to contact portions 29 proximate the free ends 28. The free ends
28 resiliently abut against the inward extensions 22 of the mating end wall 18 such
that the contact arms are in a pre-stressed condition, in order to increase the contact
force against a mating pin terminal inserted between the contact portions 29. As best
seen in figures 2 and 5, the free ends 28 of the contact arms 24 may be coined (i.e.
stamped thinner) in order to extend the length of the contact arms to enable engagement
with ledges 22.
[0016] The contact section 6 further comprises mating end side wall portions 30 that extend
from side edges 32 of the mating end wall 18 and which are bent substantially orthogonally
from the mating end wall 18, for approximate alignment with the side walls 12 as best
seen when comparing figures 6 and 7. The mating end side wall portions 30 are fairly
short in comparison to the overall length of the contact section, a rear end 34 of
the side wall portions 30 being in the vicinity (with respect to the insertion direction
(I)) of the contact portions 29 of the contacts 24. The rear end or edge 34 of the
mating end side wall portions 30 forms a locking shoulder for engagement of a connector
housing locking protrusion thereagainst in order to lock the terminals in connector
housings. As the locking shoulder 34 is in the vicinity of the contact portions 29
which are the most inwardly biased portions of the contacts in the receptacle cavity
16, interference of the contact arms with the housing locking protrusion is avoided
in a compact arrangement. In addition, the mating end side wall portions 30 provide
protection for the contact arm free end and contact portions 28, 29. The mating end
side wall portions 30 are attached to the top wall 14 (and could similarly be attached
to the bottom wall 10) by welding a top (and/or bottom) edge 38 of the side wall portions
to the top (and/or bottom) wall 14. The weld may for example be a laser generated
spot weld 40.
[0017] Attachment of the mating end side wall portions 30 to the top and/or bottom walls
provides for a rigid box-shape contact section with well protected contact portions
29 in a compact arrangement that requires particularly low material usage and wastage.
This can be understood by viewing figure 3 which shows the planar layout of sheet
metal stamped to form the various walls and contact arms, prior to the bending (forming)
operations. The length of material L in the insertion direction (I) is particularly
short, and the scrap material resulting from stamping out the arms and side walls
(see spaces 33) is particularly low in view of the advantageous arrangement of contact
arms 24, bottom 10, top 14, side 12, front 18 walls and mating end side wall portions
30 extending from side edges 32 of the mating end wall 18.
[0018] From the layout shown in figure 3, the contact arms 24 are formed and top wall halves
14a are folded up along bend lines 42 parallel to the insertion direction (I) as shown
in figure 4. Subsequently, as shown in figure 5, the side walls 12 are folded perpendicularly
from the base wall 10 around bend lines 43 extending in the insertion direction (I).
The contact pre-stressing ledges 22 may be folded from the mating end wall 18 in the
steps shown in figure 4 or figure 5, simultaneously forming the terminal receiving
cutout 20. The mating end wall 18 may then be folded upwards from the bottom wall
10 as shown in figure 6 and subsequently the mating end side wall portions 30 folded
into the side walls as shown in figure 7, and welded to the top and/or bottom walls.
Whilst the connection end wall 20 is not shown in figures 4-7, the connection end
wall halves 20a may be folded down from the top wall halves 14a in the steps of figures
6 or 7. After forming of the contact section 6, the transition and connection sections
4, 8 may be formed, the transition section 8 partially capturing the lower end 45
of the connection end wall 20 as best seen in figure 1.
[0019] The connection end wall 20 may serve to prevent matter from entering into the contact
area from a rear end of the terminal for example during over-molding of the terminal
with plastic or elastomeric material (for example for sealing purposes or assembly
in insulative housing components). In addition, the connection end wall provides a
further support for the box-shape contact section 6 to further enhance the robustness
thereof.
[0020] The mating end side wall portions 30 are further provided with a recessed portion
48 in the upper edge 47 that receives a complementary extension 50 of the top wall
14 to form an interleaving extension arrangement as best seen in figures 1 and 7.
The interleaving extensions 47, 50 assist in securely holding the mating end wall
18 to the top wall as well as securing the mating end side wall portions 30 to the
top wall to form a mating end box-shaped portion that is securely interlocked and
held together.
[0021] The contact section is further provided with secondary locking shoulders 52 directed
towards the connection section 4 and provided on extensions 54 of the side walls 12,
for engaging a secondary locking member of a connector housing thereagainst. The secondary
locking shoulders 52 are provided in a region (with respect to the insertion direction
(I)) above the transition section 8 which is of a relatively small width compared
to the contact section 6, such that a secondary locking member can be positioned behind
the secondary locking shoulder 52. In order to slim down the transition section from
the contact section sidewalls over a short distance (in the direction (I)) a cutout
56 is stamped out for the base wall of the contact section transition section.
[0022] Advantageously therefore, a particularly compact single piece electrical terminal
with low material usage and wastage is provided in a robust and compact arrangement.
1. A single piece electrical receptacle terminal (2) for mating with a complementary
tab or pin terminal, the terminal comprising a connection section (4), a transition
section (8) and a contact section (6) having a contact body with top, side and bottom
walls (14, 12, 10) forming a box-shape that defines an inner cavity area (16) for
receiving the mating terminal therein, the contact section (6) further including contact
arms (24) that extend from the opposed side walls (12) and have contact portions (29)
arranged proximate a mating end wall (18) at a mating end of the terminal, the mating
end wall (18) is provided with a cutout for guiding and locating the mating tab or
pin terminal into the inner cavity area and between the contact arms (24), wherein
the side walls (12) have mating end portions (30) attached and extending from opposed
side edges (32) of the mating end wall (18) and folded substantially orthogonally
therefrom in order to be arranged along sides of the contact section (6), the side
wall mating end portions (30) including locking shoulders (34) for locking the terminal
(2) in a connector housing, the locking shoulders positioned approximately over the
contact portions (29) of the contact arms (24).
2. The terminal of claim 1, wherein the mating end side wall portions (30) and top wall
(14) are provided with interlocking extensions (47, 50).
3. The terminal of claim 1 or 2 wherein the mating end side wall portions (30) are welded
to the top wall (14).
4. The terminal of any one of the preceding claims wherein the contact section (6) comprises
a connection end wall (20) extending substantially perpendicularly to the insertion
direction (I) proximate the connection section.
5. The terminal of claim 4 wherein the connection end wall (20) has an end (45) captured
in a U-shaped transition section (8) interconnecting the connection and contact sections.
6. The terminal of claim 4 or 5 wherein the connection end wall (20) is folded from the
top wall (14).
7. The terminal of any one of the preceding claims wherein the mating end wall (18) comprises
inwardly stamped ledges (22) against which free ends (28) of the contact arms (24)
resiliently abut for pre-stressing thereof.
8. The terminal of claim 7 wherein the free ends (28) of the contact arms (24) are coined
in order to extend the length of the contact arms for engagement with the ledges (22).
9. The terminal of any one of the preceding claims wherein the mating end wall (18) is
folded substantially orthogonally from the bottom wall (10).
10. The terminal of any one of the preceding claims wherein the bottom wall (10) is provided
with a cutout (56) proximate the transition section to facilitate inward narrowing
of side walls of the transition section, from the contact section side walls (12).