GB2107135A

GB2107135A - Flat flexible cable termination

Info

Publication number: GB2107135A
Application number: GB08226618A
Authority: GB
Inventors: Stephen A Sampson; Thor F Olson
Original assignee: Molex LLC
Current assignee: Molex LLC
Priority date: 1981-09-18
Filing date: 1982-09-17
Publication date: 1983-04-20
Also published as: GB2107135B; JPS58161277A; FR2513444A1; FR2513444B1; CA1181530A; DE3231380A1; JPS5925346B2; DE3231380C2

Abstract

A circuit assembly and method of making the same involves locating a flat flexible circuit member with an electrically conducting region 18 defined thereon between a pair of opposed, relatively rigid wafers 12a, 12b with a pin conductor (14) inserted through the member and the wafers. Each wafer includes an aperture extending through the wafer, the aperture of one wafer aligned with the aperture of the other wafer with the conducting region. The pin conductor is forced into and is retained within each aperture in each wafer, piercing the conducting region on the flat flexible circuit member in the process and making electrical contact with the conducting region. A portion of the pin conductor extends outwardly from one of the wafers for electrical connection to a female connector. <IMAGE>

Description

SPECIFICATION Circuit assembly and method of making same BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to apparatus and methods for terminating a flat flexible circuit member with a pin conductor.

2. Brief Description of the Prior Art 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 widespead acceptance.

While the flat flexible circuit members have many advantages, 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 a 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, interferring 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 advantageous since a requirement of prepunched holes adds additional cost to the production of the circuit member.

SUMMARY OF THE INVENTION It, is therefore, the principle object of the present invention to provide a circuit assembly and method of making the same 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.

In one form of the invention currently contemplated, the circuit assembly for terminating a flat flexible circuit member with a pin conductor includes a flat flexible circuit member with an electrically conducting region defined thereon. At least one pin conductor is insertable through the electrically conducting region, with the conductor in electrical connection with the conducting region on the circuit member. A pair of relatively rigid insulating wafers are positionabie in opposed relationship on opposite sides of the circuit member, and each includes an aperture alignable with the aperture of the other wafer. The apertures of each wafer are abuttable with the conducting region on the circuit member.The pin conductor is extendable through the conducting region and retainable partially within the apertures in the wafers with a portion of the pin conductor extending outwardly of at least one of the wafers.

In accordance with the invention currently contemplated, a method of making a circuit assembly including a flat flexible circuit member with a conducting region defined thereon includes the step of arranging a pair of relatively rigid wafers in opposed relationship on opposite sides of a flexible circuit member. An aperture in each wafer is aligned with the apertures of the other wafer and with a conducting region defined on the member. A pin conductor is forced through the aligned apertures and the conducting region. The conductor is then secured within each of the apertures with the conductor in electrical contact with the conducting region and extending outwardly of one of the wafers.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial perspective view of one embodiment of the circuit assembly of the present invention; FIG. 2 is an exploded view of the circuit assembly shown in FIG. 1; FIG. 3 is an enlarged cross-sectional view taken generally along the line 3-3 in FIG. 1; and FIGS. 4A through 4C are fragmentary front elevational views illustrating the method of forming the circuit assembly shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the figures, FIG. 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 1 6 which a plurality of conducting regions 1 8 defined thereon. The wafers 12 are arranged in opposed relationship on opposite sides of the circuit member 1 6 with the pin conductors 14 extending through the wafers 1 2 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 1 6. In the preferred embodiment wafers 1 2 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 1 6 resulting in a composite assembly 10 of greater stability. The wafers 12 are identical, with a pair of alignment apertures 20 arranged on oposite 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 1 6 is also provided with a pair of alignment apertures 20A, similar in size and spacing with apertures 20 provided in the wafers 1 2 and located to either side of the intended point of termination. For example, each wafer 1 2 may conveniently be made of a plastic such as polypropylene molded in the form of a rectangular block approximately 2.5 centimeters in length, 0.6 centimeters in width and 0.3 centimeters thick, the apertures 20 and 22 being formed during the molding process. The configuration of the 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 coveniently square.

As shown in FIG. 3, one end 24 of each pin conductor 22 is flush with the outwardly facing surface 26 of the upper wafer 1 2a while the other end 28 of each pin conductor 14 extends outwardly beyond the outwardly facing surface 26 of the other wafer 12b. The outward extension of the end 28 is governed by the specific application intended, it being necessary only that the outward extension be sufficient to enable connection of the conductor 14 to an appropriate female conductor of the conventional design (not shown).

In one conventional form of the flat circuit member 16, the conductive regions 18, defined on an upper surface of a base film 30, are covered by a thin insulating film 32, such as mylar or the like.

In accordance with one embodiment of present invention, the region immediately surrounding the point of intended termination of the conducting region 1 8 with the pin conductor 14 is maintained free of the insulating film 32, creating a gap 34, shown in FIG. 3.

Preferably, the pin conductor receiving apertures 22 are made of sufficiently small size to frictionally secure the pin conductors 14 within them. This can be accomplished by producing a very close tolerance between the inside size of the apertures 22 and the outside shape of the pin conductors 14 such that sufficient friction is generated upon insertion to retain the conductors 14 within the apertures 22. Alternatively, 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 resiiiently gripped by the wafers 1 2 as they force the wafer 12 material outwardly upon penetration.

The method of making the circuit assembly 10, illustrated in FIGS, 2 and 4A through 4C involves positioning the wafers 1 2a and 1 2b on opposite sides of the flat flexible circuit member 1 6. The pin conductor receiving apertures 22 of one wafer 12 are aligned with those of the opposite wafer 1 2, each adjacent and preferably in abutting relationship with the location on the conducting region 1 8 to be terminated. The alignment apertures 20 of each wafer 12 and the apertures 20A of the member 1 6 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 FIG. 2, so that the conductors 14 initially extend out of the outwardly facing surface 26 away from the member 16.

As shown in FIG. 4A, a preferred method for aligning the apertures 22 with each other and with the 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 1 2b and the flat flexible circuit member 16. In this way the apertures 22 of the wafer 1 2b are accurately aligned with the desired location of the point of termination on the circuit member 1 6. The other wafer 1 2a is then positioned on the 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, the wafer 1 2a is positioned atop the circuit member 1 6 with the pin conductors 14 extending outwardly away from the member 1 6. If desired, the pin conductors 14 are not preloaded into the wafer 1 2a but are machine fed into the wafers 12 in one operation after the wafers 12 are located in alignment.

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 FIG. 4B, causing the pin conductors 1 4 to push through the circuit member 16, forming apertures at the desired location in the conducting region 1 8 as the conductors 14 pass through the member 1 6 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 FIG. 4B, with the ends 24 of the pin conductors 14 flush with the upper surface of the wafer 1 2a 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 1 4 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 FIG. 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 conventional female connector (not 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 1 6 in the same operation.

Claims

1. A circuit assembly for terminating a flat, flexible circuit member with a pin conductor, said assembly including: a flat, flexible circuit member with an electrically conducting region defined thereon, at least one pin conductor insertable through said electrically conducting region with said conductor in electrical connection with said conducting region on said circuit member, and the improvement in said circuit assembly comprising: a pair of relatively rigid, insulating wafers positionable in opposed relationship on opposite sides of said circuit member, each of said wafers including an aperture alignable with the aperture of the other wafer, said apertures abuttable with said conducting region; and said pin conductor extendable through said conducting region and retainable partially within said apertures in said wafers with a portion of said conductor extending outwardly of one of said wafers.

2. The circuit assembly of claim 1 including means for facilitating the alignment of one of said wafers with said circuit member.

3. The assembly of claim 2 wherein said alignment means includes a pair of apertures positioned in each of said wafers and in said circuit member, each pair of apertures being spaced apart equally.

4. The circuit of claim 1 wherein said pin conductors are frictionally securable within said apertures.

5. The circuit assembly of claim 4 wherein said wafers sandwich said member between them, said wafers being secured to said member only by the insertion of said conductor through said wafers.

6. The circuit assembly of claim 1 wherein a portion of said conducting region is covered by a protective insulating film, and wherein the portion of said conducting region adjacent the point of termination is free of said film.

7. The circuit assembly of claim 1 wherein said wafers are identical and said apertures extend competelythrough each wafer.

8. A method of making a circuit assembly including a flat, flexible circuit member with a conducting region defined thereon, said member terminated by a pin conductor, comprising the steps of: arranging a pair of relatively rigid wafers in opposed relationship on opposite sides of a flexible circuit member, aligning an aperture in each of said wafers with the aperture of the other wafer and with a conducting region defined on said member, forcing a pin conductor through said aligned apertures and said conducting region, forming an aperture in said conducting region thereby, and securing said conductor within each of said apertures with said conductor in electrical contact with said conducting region and extending outwardly of one of said wafers.

9. The method of claim 8 including the step of locating said pin conductor partially within the aperture in one of said wafers preparatory to aligning the apertures of said wafers with each other and with said conducting region.

10. The method of claim 8 including the step of locating said wafers and said circuit member on an alignment means before insertion of said pin conductors in said circuit member.

11. The method of claim 10 including the step of inserting a pair of alignment posts through a pair of equally spaced apertures in each of said wafers and said circuit member.

12. The method of claim 8 including the steps of pressing said pin conductor 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 outwardly facing surface of the other of said wafers.

13. The method of claim 8 including the step of preforming said apertures in said wafers.

14. The method of claim 8 including the steps of covering said conducting region with an insulating film and maintaining the region surrounding the point of intended termination of said film.

1 5. The method of claim 8 wherein said conductor is force fitted into said wafers, said conductor being secured therein by the friction between said wafers and said conductor.

1 6. A circuit connector for terminating a flat flexible circuit member with a pin conductor, said connector comprising: a pair of electrically insulating wafers of greater stiffness than that of said flexible circuit member, each of said wafers including an identical aperture extending completely through said wafer, said apertures sized to frictionally grip said conductor upon insertion of said conductor into said apertures, the aperture of one wafer being alignable with the aperture of the other wafer; and a pin conductor retained within the aperture in one of said wafers and extending outwardly of said wafer.

17. The connector of claim 16 including means for aligning said wafers with one another.

1 8. The connector of claim 1 7 wherein said alignment means includes a pair of equally spaced apertures in each of said wafers.

19. The connector of claim 16 wherein said wafers are identical.

20. A circuit connector or method of making the same substantially as herein described with reference to the accompanying drawings.