U.S. patent number 3,768,062 [Application Number 05/184,361] was granted by the patent office on 1973-10-23 for terminal for flexible circuits.
This patent grant is currently assigned to Molex Incorporated. Invention is credited to Leonard H. Michaels.
United States Patent |
3,768,062 |
Michaels |
October 23, 1973 |
TERMINAL FOR FLEXIBLE CIRCUITS
Abstract
A terminal for attachment to a flexible circuit, or flexible
cable, serves releasably to receive a projecting male terminal in
order to establish an electrical connection between the male
terminal and the flexible circuit. The novel female terminal is
formed as a unitary body of conductive metal having a generally
planar portion together with a plurality of pointed tangs extending
from the body. The tangs are adapted to be forced through the
flexible circuit and then crimped against the circuit so that the
terminal is attached to the circuit with a "stapling" action. The
planar portion of the body is provided with a compact, effective
contact structure including a series of slots defining two spaced
generally parallel arms each of which is integral at both of its
ends with the body. A pair of interfacing contact segments on the
two arms are spaced apart from one another a distance such that the
projecting male terminal is received with an interference fit. Upon
insertion of the male terminal, cantilever movement of the contact
segments and torsional stress in the contact arms produce firm
contact between the contact segments and the projecting male
terminal.
Inventors: |
Michaels; Leonard H.
(Naperville, IL) |
Assignee: |
Molex Incorporated (Downers
Grove, IL)
|
Family
ID: |
22676566 |
Appl.
No.: |
05/184,361 |
Filed: |
September 28, 1971 |
Current U.S.
Class: |
439/77; 439/225;
439/422 |
Current CPC
Class: |
H01R
12/68 (20130101); H05K 3/326 (20130101) |
Current International
Class: |
H05K
3/32 (20060101); H01r 015/12 (); H05k 001/10 () |
Field of
Search: |
;339/14,17,19,22,32,33,95,97,15A,151A,176MF,176M,176MP,217R,2R,2C |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Champion; Marvin A.
Assistant Examiner: Lewis; Terrell P.
Claims
What is claimed as new and desired to be secured by Letters Patent
of the United States is:
1. A terminal for releasably establishing an electrical connection
between
1. a flexible circuit including a flexible conductive layer having
an opening therein, and
2. a projecting male contact having a predetermined thickness;
said terminal comprising:
a dish-shaped body formed of flexible conductive metal and
including a generally planar portion and a rim portion extending
generally normal to said planar portion;
apertures in said planar portion forming a plurality of relatively
narrow arms each integral at both ends with said body;
contact portions shorter than said arms formed as lateral
projections of said arms and extending toward one another to define
a contact space narrower than the predetermined thickness of the
male contact;
and a plurality of tangs formed as integral extensions of said rim
and extending in the same direction as said rim and generally
normal to said planar portion, said tangs being adapted to be
forced through the flexible circuit and crimped against the
flexible circuit.
2. The terminal of claim 1, said contact portions being rounded in
shape to form smooth contact receiving surfaces.
3. The terminal of claim 1, said tangs being generally pointed and
triangular in shape.
4. The terminal of claim 1, said rim surrounding said planar
portion.
5. A connection comprising a flexible circuit and a terminal
adapted to receive a projecting male contact, said terminal
comprising a dish-shaped body formed of sheet metal having a
generally planar portion and a rim extending generally normal to
said planar portion, a contact structure in said planar portion
including apertures forming a plurality of relatively narrow arms
each integral at both ends with said body, contact portions shorter
than said arms formed as lateral projections of said arms and
extending toward one another to define a contact space for
receiving the male contact with an interference fit, and a
plurality of tangs formed as integral extensions of said rim, said
tangs extending through said flexible circuit and being inwardly
crimped against said flexible circuit to hold said flexible circuit
against said rim and to bend said flexible circuit toward said
planar portion.
6. The connection of claim 5, the height of said rim exceeding the
distance that said flexible circuit is bent toward said planar
portion so that said flexible circuit is spaced from said contact
structure.
7. The connection of claim 5, said flexible circuit including a
central conductive layer sandwiched between insulating layers, said
insulating layers being intact adjacent said tangs.
8. The connection of claim 7, said tangs extending through both
said insulating and said conductive layers.
9. The connection of claim 5, further comprising an opening in said
flexible circuit aligned with said contact structure.
Description
The present invention relates to an improved terminal adapted to be
attached to a flexible circuit for receiving a projecting male
terminal.
Flexible circuits are formed of a thin layer or sheet of flexible,
conductive metal of desired configuration sandwiched between thin
insulating sheets or layers of flexible plastic or other material.
The term "flexible circuit" as used herein is intended to encompass
all such configurations including all types of more complex circuit
configurations as well as relatively simple arrangements of one or
several parallel conductors normally referred to as flexible
cables.
Due to their thinness and flexibility, flexible circuits have
advantages over conventional round wire cables and circuits.
Potentially such flexible circuits could be used in place of
discrete wires and wiring harnesses in many installations to reduce
assembly costs, prevent miswiring errors, reduce space requirements
and attain other advantages. However, adoption of flexible circuits
in many instances has been prevented by the unavailability of
suitable connectors or terminals for interconnecting the flexible
circuits easily and reliably with other electrical components.
One known method of providing an electrical connection to a
flexible circuit is to provide an uncovered region or conductive
landing on the conductive layer and to clamp, press, solder or
otherwise connect a conductive member against the conductive
region. This approach is not satisfactory because of the cost of
providing openings or landings at selected locations in the
insulation layers and the cost of the connecting operations.
Moreover, this approach is not well suited to automated
assembly.
In order to overcome this difficulty, there have been proposed
various terminal and connector devices intended to be attached to a
flexible circuit for the purpose of permitting connections to other
components. Devices of this type proposed heretofore have been
subject to difficulties such as large size, low contact density,
and the necessity for locating the terminal only at a predetermined
location such as at an edge of the flexible circuit.
Important objects of the present invention are to provide a
terminal for flexible circuits capable of being readily attached to
any covered or uncovered region of the circuit either automatically
or manually; to provide a terminal which is low in profile and
small in size thus permitting high contact density; to provide a
terminal having a female contact structure capable of providing
reliable low resistance electrical connection to a projecting male
terminal even after many insertions; to provide a terminal which
can serve to support a flexible circuit on projecting male
terminals and, moreover, which can leave projecting portions of
these terminals uncovered for connection to other structure; and to
provide a terminal capable of economical manufacture because close
production tolerances, complex shapes, and expensive materials are
not required.
Briefly, the above and other objects and advantages of the present
invention are attained by providing a terminal in the form of a
dish-shaped body fabricated of conductive metal including a
generally flat, planar portion surrounded by a rim portion. Tangs
formed as integral extensions of the rim extend generally normal to
the planar portion of the body. In order to attach the body to
either a covered or an uncovered portion of a flexible circuit, the
tangs are forced through the circuit and crimped against the
circuit thereby mechanically to mount the body on the circuit and
moreover to establish an electrical connection between the metallic
layer of the circuit and the body of the terminal.
In accordance with an important feature of the present invention
the terminal is provided with an extremely small and low profile
contact structure providing a reliable, low resistance electrical
contact between the novel terminal and a projecting male terminal.
The planar portion of the body is provided with slots or apertures
defining two spaced parallel relatively narrow arms each of which
is integral at both ends with the metallic body. Contact portions
shorter than the arms are formed as integral lateral projections of
the arms and extend toward one another to define a contact space
narrower than the corresponding dimension of the male terminal to
which a connection is to be made. When the male terminal is
received in the contact space, an interference fit with the contact
portions results in displacement of the contact portions due to
twisting in the parallel arms and due to cantilever action of the
contact portions.
The invention together with the above and other objects and
advantages may be best understood from the following detailed
description of an embodiment of the invention shown in the
accompanying drawing, wherein:
FIG. 1 is a perspective view illustrating a group of female
terminals each constructed in accordance with the principles of the
present invention attached to a flexible circuit and serving to
mount the flexible circuit on and to establish electrical
connections to a group of male terminals associated with an
electrical device;
FIG. 2 is an enlarged top plan view of a terminal constructed in
accordance with the principles of the present invention;
FIG. 3 is a sectional view taken along the line 3--3 of FIG. 2;
FIG. 4 is a side elevational view of the terminal of FIG. 2;
and
FIG. 5 is an end elevational view of the terminal of FIG. 2
Having reference now to the drawings, in FIGS. 2-5 there is
illustrated a terminal generally designated by the reference
numeral 10 embodying features of the present invention. In general,
the terminal 10 is adapted to be attached to a flexible circuit 12
and to releasably provide an electrical connection between the
flexible circuit 12 and a standard male electrical terminal 14. In
accordance with important features of the present invention, the
terminal 10 is provided with a novel female contact structure
generally designated by the reference number 16 for reliably and
releasably receiving the male terminal 14 even after multiple
insertions and removals of the male terminal. Moreover, the
terminal 10 includes a novel attaching structure generally
designated as 18 with which the terminal 10 is attached to the
flexible circuit. In combination the contact structure 16 and the
attaching structure 18 provide a terminal 10 having many important
advantages including small size, low profile, ease of attachment to
the flexible circuit and ease of connection of the terminal with
the male terminal 14.
Proceeding now to a description of the structure and use of the
terminal 10, the terminal 10 preferably comprises a unitary metal
body which may readily be formed in an automatic operation from
sheet stock by means of suitable press operations. The terminal 10
includes a generally flat or planar body portion 20 surrounded by a
continuous relatively narrow lip 22. The flat portion 20 and lip 22
cooperate to provide a generally dish-shaped configuration.
Referring now more specifically to the attaching structure 18, the
terminal 10 is provided with a plurality of projecting tangs 24
formed integrally with the lip 22 and initially extending normal to
the plane of the flat portion 20 as illustrated in FIGS. 4 and 5.
The tangs 24 are generally triangular in shape and include pointed
ends 26 to facilitate forcing of the tangs through the flexible
circuit. In order to permit mounting or "stapling" of the terminal
10 reliably and firmly to the flexible circuit, preferably the
tangs are arranged in opposed pairs. Although in the illustrated
arrangement there are two opposed pairs, or a total of four tangs,
it should be understood that other configurations could be used for
particular terminal sizes and shapes.
As is well known to those skilled in the art, the flexible circuit
12 includes outer layers of insulating material 30 sandwiched
around an internal conductive metallic layer 32. The circuit 12 is
provided with an opening 33 over which the terminal 10 is located.
Attachment of the terminal 10 to the flexible circuit 12 is
accomplished by driving or forcing the tangs 24 through the
flexible circuit 12 and by inwardly bending or crimping the tangs
against the surface of the flexible conductor as shown in FIGS. 2
and 3. This attaching operation can readily be carried one either
manually by means of a suitable pliers tool or automatically by
means of suitable equipment. Each tang 24 penetrates the full
thickness of the flexible circuit 12 and is bent inwardly against
an outer layer of the circuit. Inward crimping of the tangs
produces a slight flexing or bending of the flexible circuit as
shown in somewhat exaggerated fashion in FIG. 3 in order firmly to
hold the flexible circuit between the tangs 24 and the edge of the
lip 22 as indicated by the reference numeral 28 in FIG. 3.
Electrical contact between the body of the terminal 10 and the
metallic layer 32 occurs at the regions where the tangs 24 pierce
the flexible circuit 12. The slight bending or flexing of the
flexible circuit created by crimping of the tangs serves to provide
a resilient spring contact between the metallic layer 32 and the
tangs 24 sufficient to provide a large area, low resistance path
for the flow of current between the terminal 10 and the metallic
layer. It is not necessary for the pointed ends 26 of the tangs 24
to reenter the flexible circuit in order to provide sufficient
electrical contact. However, if desired, the tangs upon attachment
of the terminal 10 can be driven against an anvil of suitable
configuration to produce such reentry. It also is not necessary
that the terminal 10 be attached to an uncovered region of the
metallic layer 32, and good contact is achieved upon both covered
and uncovered regions.
Referring now more specifically to the contact structure 16 of the
present invention, the flat portion 20 of the terminal 10 is
provided with three slots or apertures 34, 36 and 38 serving to
define two elongated narrow spaced arms 40 and 42. Each arm 40 and
42 is provided with a central contact portion 44 and 46.
As best shown in FIGS. 2 and 3, the contact portions 44 and 46
project from the arms 40 and 42 toward one another to provide a
contact receiving space designated by the reference numeral 48. The
distance between the contact portions 44 and 46 is selected to be
smaller than the corresponding dimension of the terminal 14 with
which the terminal 10 is to be used. Thus, upon insertion of the
terminal 14, there exists an interference fit between the terminal
14 and the contact portions 44 and 46.
In order to facilitate both insertion and withdrawal of the
terminal 14 and in order to permit insertion of the terminal 14
from either direction relative to the terminal 10, the contact
portions are curved or rounded to present smooth curved surfaces 50
interfacing in the contact space 48.
As best seen in FIG. 2, the contact portions 44 and 46 are shorter
in length than the arms 40 and 42 and are located substantially in
the center of the arms 40 and 42. Thus, the arms 40 and 42 include
end portions of relatively narrow width extending between the
contact portions and the main body of the terminal 10. Upon
insertion of the terminal 14 with an interference fit between the
contact portions 44 and 46, the arms 40 and 42 twist as a torsional
stress is placed upon the arms. Moreover, to some degree, the
contact portions 44 and 46 serve as short cantilever beams placed
in bending stress by insertion of the terminal 14. The overall
effect of the torsional stress and the bending stress in the arms
40 and 42 and in the contact portions 44 and 46 is to provide a
firm resilient biasing of the smooth curved surfaces 50 intimately
against the terminal 14. In this manner there is provided a
reliable low resistance electrical connection between the contact
portions 44 and 46 and the surfaces of the terminal 14. Moreover,
this reliable electrical connection is maintained even after many
insertions and withdrawals of the terminal 14. It has been found
that close production tolerances are not necessary since the
contact design affords substantial variation in contact spacing
while still providing good electrical contact. In addition,
twisting and/or skewing of the terminal 14 in the terminal 10 does
not interfere with the electrical connection.
The combination of the contact structure 16 and the attaching
structure 18 provides a terminal 10 which is extremely small in
size requiring only minimal area. As a result, high contact density
is possible and the terminals 10 can be mounted quite close to one
another. Moreover, the thickness or profile of the terminal 10 is
small and adds only slightly to the thickness of the flexible
circuit. In addition, the terminal 10 can be attached to any
desired location on the flexible circuit and does not require
removal of an insulating layer from the circuit.
As indicated in the somewhat diagrammatic illustration comprising
FIG. 1, these several important advantages of the terminal 10
greatly facilitate the use of a flexible circuit with electrical
devices or electrical equipment such as the electrical device 52
indicated in phantom in FIG. 1. It should be understood that the
device 52 may comprise any electrical component such as a switching
device, controlling device, appliance or the like including several
projecting male terminals 14 arranged in any desired configuration.
The flexible circuit illustrated in FIG. 1 and designated as 54
includes discrete conductive metallic layers 56 arranged in
suitable configuration for connection to the plurality of male
terminals 14.
Upon insertion of the several male terminals 14 of the device 52
into the several properly located terminals 10 supported by the
circuit 12, the flexible circuit is self-supported upon the
terminals 14 and no additional external supporting structure is
required. The arrangement of FIG. 1 has several important
advantages as compared with conventional discrete wire connections.
The entire operation may be carried out automatically, and manual
miswiring errors and the like are avoided. In addition, assembly
costs are reduced and the space requirements for connection to the
device 52 are minimized.
Another important advantage of the terminal 10 can be seen from
FIG. 1. As there illustrated, each male terminal 14 projects well
beyond each terminal 10 due to the minimal thickness or low profile
of the terminal 10. This makes possible further connections to each
male terminal 14. Thus, there is illustrated a releasable slip-on
terminal 58 engaging the exposed portion of one terminal 14 which
extends beyond the corresponding terminal 10.
Although the invention has been described with reference to details
of the illustrated embodiment, it should be understood that the
invention is not limited to the illustrated embodiment but rather
is defined by the scope of the following claims.
* * * * *