Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates generally to a method for terminating a
flat flexible circuit member with a pin conductor.
Due to their low cost, flat flexible circuit members wherein a
pattern of conducting regions are defined by coating or the like on a
flexible plastic film have gained widespread acceptance. While the flat
flexible circuit members have many advan-tages, some difficulty is
experienced in terminating such members because of their flexibility.
In the past flat, flexible circuit members have been terminated
in one of two ways. In one method, known as the insulation displacement
method, the circuit member is pierced with a sharp portion of a terminal
and the terminal is then either crimped or clinched against the circuit
member. In the other method, prepunched holes are formed in the circuit
member and a pin conductor or the like is then inserted through the holes.
The insulation displacement method is less than optimal since the
displacement of the insulation may be incomplete, interfering with the
electrical connection between the conducting region on the circuit member
and the terminal itself. In addition, the flexibility of the circuit
member makes it difficult to crimp or clinch the sharp portion of the
terminal to the circuit member. The method involving prepunching of holes
in the circuit member is disadvantageous since a requirement of prepunched
holes adds additional cost to the production of the circuit member.
It is, therefore, the principle object of the present invention
to provide a method of making a circuit assembly in which a flat flexible
circuit member is terminated with a pin conductor in a manner which is
efficient and inexpensive and overcomes many of the disadvantages experienced
in the prior art.
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In accordance with a broad aspect of the invention there is
provided a method of making a circuit assembly including a flat, flexible
curcuit member with a conducting region defined thereon, said member
terminated by a pin conductor, comprising the steps of: arranging a pair
of relative~y rigid wafers in opposed relationship on opposite sides of a
flexible circuit member, inserting a pair of alignment posts having first.
ends secured to a support plate, through a pair of equally spaced apertures
in each of said wafers and said circuit member in order to align an
aperture in one of said wafers with an aperture of the other wafer and with
a conducting region defined on said member, pressing a pin conductor
through said aligned apertures of said wafers and said conducting region,
forming an aperture in said conducting region thereby, said pin conductor
being pressed through said wafers until one end of said pin conductor is
flush with the surface of one of said wafers and the other end of said pin
conductor extends outwardly of the woutwardly facing surface of the other of
said wafers, and securing said conductor within each of said apertures so
as to force fit said pin conductor in said wafers, with said pin conductor
in electrical contact with the said conducting region and extending outwardly
of one of said wafers.
The invention will now be further described in conjunction with the
accompanying drawings, in which:
Figure 1 is a partial perspective view of one embodiment of the
circuit assembly of the present invention;
Figure 2 is an exploded view of the circuit assemb.ly shown in
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Figure l;
Figure 3 is an enlarged cross-sectional view taken generally
along the line 3-3 in Figure l; and
Figures 4A through 4C are fragmentary front elevational views
illustrating the method of forming the circuit assembly shown in Figure 1.
Turning now to the figures, Figure 1 illustrates a circuit
assembly, generally designated 10, of the present invention including a
pair of opposed relatively rigid electrically insulating wafers 12~ a
plurality of pin conductors 14 and a flat flexible circuit member 16 with
a plurality of conducting regions 18 defined thereon. The wafers 12 are
arranged in opposed relationship on opposite sides of the circuit member 16
with the pin conductors 14 extending through the wafers 12 and the circuit
member 16 so as to secure -the entire assembly 10 together in a stable
mounting.
Each wafer 12 is conveniently formed of a nonconducting material
such as plastic or the like, preferably of sufficient thickness to have
greater rigidity than that possessed by the flexible circuit member 16.
In the preferred embodiment wafers 12 are sufficiently stiff to resist
manual flexing. As used herein the term "relatively rigid wafers" means
only that the wafers are less flexible than the flexible circuit member
16 resulting in a composite assembly 10 of greater stability. The wafers
12 are identical, with a pair of alignment apertures 20 arranged on
opposite ends of the conveniently rectangular wafer 12 and a plurality of
pin conductor receiving apertures 22 arranged in a line between the
alignment apertures 20. The member 16 is also provided with a pair of
alignment apertures 20A3 similar in size and spacing with apertures 20
provided in the wafers 12 and located to either side of the intended
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point of termination~ E`or example, each wafer 12 r~ay convem ently ~e
made of a plastic such as polypro~ylene molded in ~le form of a
rectangular block approximately 2.5 centimeters in length, 0.6
centimeters in width and 0.3 centir~2ters thick, ~he apertu~es 20 and
22 beinc~ formed during the moldiny process. me configuration of ~le
apertures 22 corresponds with the cross-sectional shape of the pin
conductors 14, and in the illustrated embodiment with pin conductors
14 of a square cross-sectional configuration, the apertures 22 are
also conveniently square.
~s shown in Figure 3, one end 24 oL each pin conductor 22 is flush
with the outwardly facing surface 26 of the upper wafer 12a while the
other end 28 sf each pin conductor 14 extends outwardly beyond the
outwardly facing surface 26 of the other wafer 12b. m e outward
extension of the end 28 is governed by the specific a~pplication
intended, it bein~ n~cessary only that the out~Jard extension be
sufficient to enable connectoin of the conductor 14 to an appropriate
female conductor of conventional design ~not shown)~
In one con~7entional form of the Llat circuit mem~er 16~ the
conductiny regions 18, defined on an upper surface of a ~ase film 30,
are covered ~y a thin insulating film 32, such as "l~i~71ar'~0r ine like.
In accordance w1th one embodiment of present invention, the region
imm~diately surrounding the point of intended termination of the
conducting region 18 within the pin conductor 14 is maintained free of
the insulating film 32, creating a gap 34, shGwn in Figure 3.
Preferably, the pin conductor receivin~ apertures 22 are
made of sufficiently small size to frictior~lly secure the
pin conductors 14 within them. This can be accom-plished by
producing a very close tolerance betsYeen the inside size of
the apertures 22 and the outside shcape of the pin
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conductors 14 such that sufficient friction is generated upon insertion
to retain the conductors 14 within the apert~res 22. AlternativelyJ the
wafers 12 may be made of somewhat resilient material such as hard rubber,
resilient plastic or the like such that the conductors 14 are resiliently
gripped by the wafers 12 as they force the wafer 12 material outwardly
upon penetration.
The method of making the circuit assembly 10, illustrated in
Figures 2 and 4A through 4C involves positioning the wafers 12a and 12b
on opposite sides of the flat flexible circuit member 16. The pin
conductor receiving apertures 22 of one wafer 12 are aligned with those of
the opposite wafer 12, each adjacent and preferably in abutting
relationship with the location on the conducting region 18 to be terminated.
The alignment apertures 20 of each wafer 12 and the apertures 20A of the
member 16 are also aligned with each other. In accordance with one
preferred embodiment of the present invention; the pin conductors 14 are
preloaded into the wafer 12a, as shown in Figure 2, so that the conductors
14 initially extend out of the outwardly facing surface 26 away from the
member 16.
As shown in Figure 4A, a preferred method for aligning the
apertures 22 with each other and with ~he desired location for termination
utilizes a plate 36 with a pair of upwardly extending, spaced posts 38.
Since the spacing between the posts 38 coincides with that between the
apertures 20, the conveniently curved free ends 40 of each post 38 are
telescoped through the apertures 20 of the wafer 12b and the flat flexible
circuit member 16. In this way the apertures 22 of the wafer 12b are
accurately aligned with the desired location of the point of termination
on the circuit member 16. The other wafer 12a is then positioned on the
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plate 36 with the posts 38 extending through its alignment apertures 20 as well.
In an embodiment in which the pin conductors 14 are preloaded into
the wafer 12a, ~he wafer 12a is positioned atop the circuit member 16 with
the pin conductors 14 extending outwardly away from the member 16. If
desired, the pin conductors 14 are not preloaded into the wafer 12a but are
machine fed into the wafers 12 in one operation after the wafers 12 are
located in 21 ignment.
In the illustrated embodiment using a preloaded wafer~ press 44
is initially located over the free ends 24 of the pin conductors 14 now
extending upwardly away from the upper wafer 12a. The press 44 is
operated to move toward the assembly 10, as indicated by the arrow in
Figure 4B, causing the pin conductors 14 to push through the circuit member
16, forming apertures at the desired location in the conducting region 18
as the conductors 14 pass through the member 16 and into the wafer 12b.
The downward motion of the press 44 is continued until the pin conductors
14, force fitted into the apertures 22, are in the position, shown in
Figure 4B, with the ends 24 of the pin conductors 14 flush with the upper
surface of the wafer 12a and the ends 28 extending downwardly from the
outwardly facing surface 26 of the wafer 12b. Apertures 46 are provided
in the plate 36 to receive the ends 28 of the conductors 14 as they are
pressed through the lower wafer 12b. Preferably the apertures 46 are larger
than the apertures 22 so that the conductors 14 freely slide through the
apertures 46, the apertures 46 merely providing clearance for movement
of the conductors 14.
The press 44 is thereafter withdrawn, as shown in Figure 4C,
and the completed circuit assembly 10 may be lifted from the plate 36. The
resulting circuit assembly 10 is sturdy and may easily be connected to a
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conventional female connector ~no~ shown). Thus~ despite the flexible
nature of the circuit member 16, a stable mechanical base is formed for
subsequent connection to other components. If desired, a plurality of
assemblies 10 may be formed on one member 16 in the same operation.
