Electrical Connections To Flat Conductor Cable

Abstract

An electrical connection between a terminal post and a flat conductor in a flat conductor cable comprises a connecting member disposed on the cable in parallel relationship to the conductor. The connecting member, which is crimped through the cable and onto the conductor, has an opening through which the terminal post extends. Electrical contact between the post and the connecting member is achieved by curled portions of the connecting member and/or portions of the flat conductor which are in engagement with the terminal post.

Description

BACKGROUND OF THE DISCLOSURE

This invention relates to electrical connections between terminal posts and flexible flat conductors. The term "flexible flat conductor" is used herein in a generic sense to include such conductors in conventional flexible flat cables and flexible circuitry, of the type produced by etching or otherwise. Conductors of these types comprise flat conductors encased in an insulating film such as Mylar (polyethyleneterephthalate). The conductors in a flexible flat cable are usually of uniform width and extend parallel to each other throughout the length of the cable while the conductors in flexible flat circuitry may extend along irregular paths and may have enlarged portions at some locations to which electrical components are adapted to be connected.

It is frequently desirable to electrically connect electrical contact posts to the conductors of flexible flat conductors and this has frequently been done in the past by means of soldered connections as disclosed, for example, in U.S. Pat. No. 3,537,176. One type of connecting device which is adapted to be crimped onto a flat conductor for forming connections between flat conductors and contact posts is disclosed in application Ser. No. 70,137 filed in the United States on Sept. 8, 1970.

The instant invention is specifically directed to the achievement of an electrical connection between a contact post and a flat conductor in a flexible flat conductor device which is of minimum size and can be applied in a simple and straightforward manner to the conductor. The invention is further directed to the achievement of an electrical connection between a flat conductor and a terminal post which does not require an irregularly formed section, such as a circular pad, in the conductor for the connection.

It is accordingly an object of the invention to provide an improved connection between a terminal post and a conductor in a flexible flat conductor such as a flexible flat circuit or a flexible flat cable. It is a further object to provide an electrical connection which is extremely small in size and can be used with circuit devices having conductors located on closely spaced centers. It is a further object to provide an electrical connection between a flat conductor and a terminal post by means of a connecting device which can be crimped onto the conductor. A further object is to provide a low resistance connection having a high degree of reliability which is suitable for critical applications.

These and other objects of the invention are achieved in a preferred embodiment thereof which is briefly described in the foregoing abstract, which is described in detail below, and which is shown in the accompanying drawings which:

FIG. 1 is a perspective view of a flat conductor cable, the conductors of which are connected to the terminal posts extending from a panel member.

FIG. 2 is a fragmentary perspective view, on an enlarged scale, of two electrical connections, between terminal posts and flat conductors in accordance with the invention.

FIGS. 3 and 4 are taken along the lines 3--3 and 4--4 of FIG. 2.

FIG. 5 is a perspective view of uncrimped connecting device in accordance with the invention.

FIG. 6 is a side view of the connecting device shown in FIG. 5.

FIG. 7 is a perspective view of an alternative form of connecting device in accordance with the invention.

FIG. 8 is a side view of the connecting device of FIG. 7.

FIG. 9 is a sectional view of a connecting device crimped onto a conductor prior to punching of the cable and sizing of the connector sidewalls.

FIG. 10 is a view similar to FIG. 9 but illustrating the cable punching and connector sizing operations.

FIG. 11 is a fragmentary perspective view of the manner in which the conductors of two cables can be connected in accordance with the invention.

Referring first to FIG. 1, a typical flat conductor cable 2 comprises a plurality of flat ribbon-like conductors 4 arranged in parallel side-by-side relationship within a film 10 of suitable plastic such as polyethylenetere-phthalate. The conductors of conventional flat cables are generally parallel to each other and spaced apart by uniform distances although the conductors in flexible flat circuits may have irregular widths and extend along irregular paths. The invention is herein disclosed with relation to conventional flat cable in the interest of clarity and simplicity.

Where it is desired to form electrical connections between the conductors 4 of the cable and terminal posts 6, it has been common practice in the past to punch holes in the cable, position the cable on the posts and solder the posts to the conductors. The terminal posts 6 may be mounted in any suitable support member 8 which may be a typical printed circuit board or it may be mounted in a component such as a switch or relay. As shown in FIGS. 3 and 4, these terminal posts may extend entirely through the board.

In accordance with the instant invention, the conductors 4 may be electrically connected to the post 6 by means of a connector 12 (FIGS. 5 and 6) which is generally U-shaped in cross-section having a web 14 and sidewalls 16 extending from the longitudinal edges of the web. The upper edges of the sidewalls may be chamfered as shown in 17 and the ends of the sidewalls bevelled as shown at 18. The sidewalls are also provided with slots 20 which extend partially downwardly from the upper edges as shown for purposes which will be described below.

A lance 22 is struck upwardly adjacent to the lefthand end of the connecting device as viewed in FIG. 6 and the web, in the vicinity of the lance, is coined as shown at 24 to cause some of the metal to flow into the opening which is formed when the lance is formed from the web. As a result of this coining operation, the lance cannot move into the opening but engages the coined portion of the web as is shown in FIG. 4 when the terminal is crimped onto the conductor in the circuit.

A hole 26 is punched in the web adjacent to the righthand end thereof, the diameter of this hole being such that the post 6 will fit freely therethrough although the hole 26 need not be grossly oversized relative to the size of the post.

The connector 12 is applied to the conductor by aligning the connector with the conductor 4, forcing the sidewalls through the insulation so that they straddle the conductor, and subsequently curling the sidewalls inwardly towards each other and towards the web as shown best in FIG. 3. This type of crimped connection is fully disclosed and claimed in U.S. Pat. No. 3,395,381, and U.S. Pat. No. 3,553,836 discloses an apparatus for applying connecting devices shown in FIG. 6 to flat conductors. As explained in U.S. Pat. No. 3,395,381, the longitudinal edges 17 of the sidewalls penetrate the film on the underside of the cable and contact the conductor. As shown best in FIG. 4, a portion 30 of the conductor is tightly held between the edge of each sidewall and the lance 22 and since the lance cannot return to its original position or cannot be moved upwardly beyond the position shown in FIG. 4, the engagement of the sidewalls with the lance and the conductor cannot relax so that a permanent low resistance electrical connection can be achieved. The righthand portion of the connecting device as used in FIG. 4 is also crimped onto the cable by curling the sidewalls inwardly towards each other and towards the web. After application of the connecting device to the cable, the opening 26 in the web will be directly above the conductor 4.

Referring to FIGS. 9 and 10, it will be noted that after crimping, the distance w between the opposed curled surfaces of the sidewalls in the vicinity of the hole 26 of the connector is somewhat less than the width w' of the post 6. A hole is then punched through the cable concentrically with respect to the hole 26 in the connecting device by a punch 32 which has a width w substantially equal to the width of the terminal post 6. During punching of this hole in the cable then, the portions of the curled sidewalls adjacent to the hole 26 are sized or sprung apart by a slight amount so that the terminal post 6 is permitted to move through the connecting device in a manner as described below. The slots 20 in the sidewalls of the cable tend to isolate this working of the curled portions of the sidewalls when the hole in the cable is punched so that the electrical connection at 30 between the connecting device and the conductor is not disturbed by this hole punching operation. Advantageously, the punching operation is carried out at the time the connecting device is crimped onto the conductor.

After the hole has been punched in the cable, the conductor can be electrically connected to the post 6 by simply locating the cable above the post and moving the cable downwardly over the post. The curled sections of the sidewalls will frictionally engage the sides of the posts and establish a low resistance stable electrical connection between the post and the connector so that the post is thereby connected to the conductor 4. The margins of the cable within the opening 26 or which extends beyond the edges 26 will be flexed upwardly as shown in FIG. 4 when the cable is moved downwardly over the post and some electrical contact between the post and the conductor will be obtained at the exposed portion of the conductor although the primary connection is at 30 between the connecting device and the flat conductor.

Where it is desired to connect the individual conductors in a cable or flexible circuit to a plurality of posts, it is merely necessary to crimp connecting devices onto the conductors of the cable at locations corresponding to the locations of the terminal posts and to move the entire cable downwardly over the posts as shown in FIG. 1. The posts 6 may be rectangular as shown or maybe have a circular cross-section. The punch should, of course, be designed to size the sidewalls of the connector accordingly to fit the post to which connections are to be made.

When it is desired to have a connecting device of minimum size, the embodiment of FIG. 5 can be employed. If a larger connecting device can be tolerated, the embodiment of FIG. 7 provides two electrical connections between the web of the connector and the conductor 4. In this embodiment the opening, which is rectangular in this case, is provided between the two lances and two slots are provided to isolate the central portions of the sidewalls.

The terminal posts may be circular as shown in FIG. 12 or rectangular so long as they are dimensioned so as to make electrical contact with the curled portions of the sidewalls of the connecting devices. Square or rectangular posts are widely used in the electronic industry for making clip-type or wrap-type connections and these same posts can be used for connections in accordance with the instant invention. Cylindrical posts on the other hand are advantageous in that no particular orientation of the post relative to the connector is required.

FIG. 11 illustrates the manner in which the conductors of two cables 2, 2' can be electrically connected to each other in accordance with the invention. The lower cable 2 is assembled to a diagonally extending row of posts in a manner such that each post extends through a connecting device crimped onto one of the conductors of this lower cable. The upper cable 2" is similarly assembled to the same posts so that conductors in the two cables which are electrically connected to a common post are connected to each other. It will be apparent that the cables 2, 2" need not necessarily extend normally of each other but can extend at any desired angle to each other so long as the terminal posts are properly positioned to engage connecting devices in both of the cables.

Where it is desired to provide a common ground for each, or selected ones, of a plurality of conductors in a cable, connecting devices of the type shown at 12 can be crimped onto a thin set of conductive foil and this foil connected to each of a plurality of posts in the same manner as is a cable. The conductors of the cable are then connected to the same posts in accordance with an invention.

Where three or more cables are to be connected selectively, diode type posts can be used to form, for example, electrical connectors between selected conductors of the upper most cable and conductors of the lower most cable with insulated portions of the post in engagement with connecting devices crimped to the center cable. It is necessary, under these circumstances, to crimp a connecting device onto the center cable to permit assembly or mounting of all three cables on the posts.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

Claims

What is claimed is:

1. An electrical connection between a terminal post and a flat conductor, said connection comprising:

an electrical connecting device crimped onto said conductor, said connecting device comprising a web and sidewalls extending from two opposite edges of said web, an opening in said web located centrally between said sidewalls, said sidewalls being curled inwardly towards each other and towards said web and being in engagement with said conductor, spaced-apart curled portions of said sidewalls being disposed on opposite sides of said opening,

said post extending through said opening and being in engagement with said sidewalls.

2. An electrical connection as set forth in claim 1 wherein said post is mounted in a panel-like member and has a free end, said connecting devises being oriented on said post with said sidewalls opposed to said panel-like member.

3. An electrical connection between a terminal post and a flat conductor, said flat conductor being contained in insulating film, said connection comprising:

an electrical connector crimped onto said conductor, said connector having a web and sidewalls extending from the longitudinal edges of said web, said web being against said insulating film on one side of, and parallel to, said conductor, said sidewalls extending through said insulating film to the other side thereof in straddling relationship to said conductor, the marginal edge portions of said sidewalls being curled inwardly and extending towards said web and being in electrical contact with said conductor,

aligned openings in said web, said film, and said conductor, said openings being between said sidewalls,

said post extending through said opening and being against, and in frictional engagement with, said curled sidewalls and establishing electrical contact between said connector and said post.

4. An electrical connection as set forth in claim 3 wherein said post has a circular cross-section.

5. An electrical connection as set forth in claim 3 wherein said post has a rectangular cross-section.

6. An electrical connection as set forth in claim 3 wherein portions of said conductor adjacent to said opening in said conductor are in contact with said post.

7. An electrical connection as set forth in claim 3 wherein said post is mounted in a panel-like member and has a free end, said connecting device being oriented on said post with said curled marginal edge portions of said sidewalls opposed to said panel-like member.

8. A plurality of individual electrical connections between individual terminal posts mounted on a support member and the individual conductors in a flat conductor cable or the like, said cable comprising spaced apart flat conductors encased in plastic film material, each of said connections comprising:

an electrical connector crimped onto one of said conductors, said connector comprising a web and sidewalls extending from two opposite longitudinal edges of said web, said web being against said insulating film on one side of, and parallel to, said one conductor, said sidewalls extending through said insulating film to the other side of said cable and being in straddling relationship to said conductor, the marginal edge portions of said sidewalls being curled inwardly and towards said web and being in electrical contact with said conductor,

aligned openings in said web, said film, and said conductor, said openings being between said sidewalls,

said post extending through said openings, and being against, and in engagement with, said curled sidewalls, portions of said conductor adjacent to said opening in said conductor being in engagement with said post,

said cable being oriented on said post with said curled sidewall portions opposed to said support member.

9. The structure set forth in claim 8 and an additional flat conductor cable or the like, and individual electrical connections as set forth in claim 8 between said posts and said conductors in said additional cable.