US 3395381 A
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Description (OCR text may contain errors)
UCTOR CABLE July 30, 1968 c. w. HUFFNAGLE CRIMPABLE CONNECTING DEVICE FOR FLAT COND Filed Nov. 25, 1966 r MW,
United States Patent O ABSTRACT OF THE DISCLOSURE Crimpable U-shaped connecting device for flat conductor cable has lances struck from the web of the U with openings in web 'Vnear lances. The web is coined near the openings so that the coined and elongated sections function as stops preventing the lances from being bent back into the plane of the web. Upon crimping, the connector is placed in straddling relationship to the conductor of the at conductor cable and the sidewalls are bent inwardly and towards each other. The conduct-or is pinched between the lances and the ed-ges of the inwardly bent sidewalls, the stops functioning to maintain the contact pressure between the lances and/or the sidewall edges and the conductor.
Background of the nventio-n Flat conductor cable comprises a tape-like strip of suitable plastic in which there are embedded a plurality of ribbon-like conductors extending parallel to each other. Conductor cable of this type has been widely available for some years although conventional terminating and crimping techniques as are commonly applied to round wires .are not applicable to this type of cable. As a result, a wide variety of specialized types of connecting devices have been developed for at conductor cable.
The yprior art shows both crimp-type terminations for iiat conductor cable and solder-type terminations, In many prior art'vdevices, preparation of the cable by way of stripping of the insulation is necessary preparatory to ap`- plication of the terminal to the cable. In other devices, the connector is intended to pierce and be crimped through the; insulation to make contact with the ribbonlike conductors of the cable. The present invention relates to that class of terminating devices for ilat conductor cable in which the insulation is pierced and no prior preparation of the cable is necessary when the terminal or connecting device is applied thereto.
Summary of the invention In accordance with a preferred embodiment of the invention, the connecting device has a channel or U-shaped cross-section comprising a web and upstanding sidewalls extending from the web. Lances are struck inwardly from the plane of the web leaving an opening in the web adjacent to each of the lances. These lances extend obliquely from the plane of the web and are disposed between the sidewalls with their edges extending transversely across the web. The remaining material of the web is coined or -otherwise elongated in the vicinity of these openings after the lances and sidewalls have been formed thereby rendering these openings somewhat smaller than their originalsize and preventing the lances from moving back into the plane of the web. The deformed portions of the web thus function as stops for the lances limiting their movement towards the plane of the web during crimping. In use, the connector is positioned on the ilat conductor cable with the sidewalls in straddling relationship thereto and is punched through the cable on each side of the conductor to penetrate the insulation. The sidewalls are then curled inwardly and then towards the web until they ice move against the conductor and press it against the edges of the lances. The lances themselves may be bent back towards their original position, but can not return to their initial positions in the plane of the web because of the stops noted above. In the iinal crimped connection then, the conductor is pinched between these lances and edges of the sidewalls `and electrical contact is established between the connector and the conductor. The spring effect of the deformed or curled sidewalls coupled with the xed lances, which can not move because of the stop members, provide a stable, low resistance electrical connection which occupies the minimum of space and, in addition, provides a sound mechanical connection between the connector and the flat conductor cable.
It is accordingly an object of the invention to provide an improved crimpable connector for flat conductor cable. A further object is to provide a crimped connection for ilat conductor cable in which residual stresses in the connector are utilized to maintain the connection under varying environmental conditions such temperature variations which would -otherwise cause relaxation with concomitant deterioration of the electrical connection. A still further object is to provide a crimpable connection for at conductor cable which is relatively low in cost, easily made, and which occupies an amount of space compatible with the spacing of the condu-ctors in the at conducto-r cable.
Brie]c description of the drawing FIGURE 1 is a perspective view of a short section of at conductor cable;
FIGURE 2 is a perspective view of one form of electrical connecting device in accordance with the invention;
FIGUR-E 3 is a longitudinal cross-sectional view of the connector of FIGURE 2,
FIGURE 4 is a transverse sectional view showing the connector of FIGURE 2 crimped onto a ilat conductor cable;
FIGURE 5 is a longitudinal sectional view taken along the lines 5-5 of FIGURE 4;
FIGURE 6 is a perspective View of a crimped electrical connection in accordance with the invention;
FIGURE 7 is a View similar to FIGURE 3, but showing the structure of the connector prior to a coining operation in which stop means for the lan-ces are formed; and
FIGURE 8 is a perspective View of an alternative embodiment.
Description of the preferred embodiment Referring rst to FIGURE l, a typical form of flat conductor ycable 2 comprises a plurality of ribbon-like conductors 4 in parallel spaced-apart relationship. The conductors are insulated and maintained in their parallel relationship by two strips or layers 6 of suitable plastic film such as Mylar (polyethylene terephthalate) between which the conductors are laminated and which are suitably bonded to each other. The polyethylene terephthalate insulation is extremely tough and ldurable and can be stripped from the conductors only with the greatest of diiiiculty because of the tenacity with which it is bonded. Furthermore, the conductors are relatively thin and any abrasive stripping operation carried out for the purpose of removing the insulation will sometimes remove some of the metal in the conductors thereby `decreasing their effectiveness.
A preferred form of connecting device 8 in `accordance with the invention has a ferrule-forming crimp portion generally indicated at 10 and a contact portion 12 extending therefrom. This contact portion can take any desirable form, for example, it can comprise a simple post adapted to be connected to a further conductor by wrap-type or clip-type techniques or it can comprise a spring-type contact member adapted to make contact with the conductors on a printed circuit board. In the latter case, where the contact member 12 comprises a spring-type contact, the entire assembly including the end of the cable and the crimp portions would be mounted in a suitable connector housing. The present invention is directed primarily to the crimp .portion 10 of the connector and the manner in which it is secured to the end of the flat conductor cable.
Crimp portion 10` comprises a web 14 from which sidewalls 16 extend, the longitudinal edges of these sidewalls being bevelled as shown at 18 to facilitate the crimping operation during which these edges must penetrate the insulating film 6 of the cable. The sides 20 of these sidewalls are tapered as shown in order to facilitate curling of the sidewalls during crimping.
The web portion 14 of the connector is provided with a pair of opposed inwardly directed lances 22, 24 which are struck from the plane of the -we-b whereby openings 28 remain in the plane. The openings 28 will be shown in FIGURE 7 immediately after the lances 22, 24 are struck from the web so that the lances could move back or be bent back into the plane of the web. In order to provide a stop :member adjacent to each of the lances and prevent movement of these lances back to their original position, the web is coined by indentation with a suitable punch as shown at 32, this coining operation resulting in an elongation of the web adjacent to the lances as shown at 34 whereby the size of the openings 28 is reduced. As will be apparent from FIGURES 3 and 5, after the coining operation has been carried out, the lances 22, 24 can not move back to their original positions but can move only against the edges of the stops.
In use, the connector is positioned in overlying relationship to the flat conductor cable with the conductor 4 to which a connection is being made extending parallel to the plane of the web. It -will be noted that the width of the web 14 is somewhat less than the width of the conductor 4 in the disclosed embodiment. The connector is then pressed through the fiat conductor cable so that the marginal portions of the conductor 4 are curled slightly as indicated in FIGURE 4 and the sidewalls are then curled inwardly and are reversely curled towards the plane of the web until they bear against the underside of the cable, penetrate the insulation thereof, and contact the conductor. During this crimping operation, the sidewalls will clamp the conductor against the edges 26 of the lances and, under preferred conditions, bend the lances back towards t-he plane of the web until they engage the stop portions 34 thereof as shown in FIGURE 5. During this crimping operation, the edges of the sidewalls will penetrate the film, and the film will be penetrated by the edge portions of the lances so that redundant contacts will be obtained in a single crimped connection.
In the finished connection, the curled sidewalls function as springs pressing the conductor against the lances as shown in FIGURE 5 which are incapable of upward movement because of the presence of the stops 34. A crimped connection in accordance with the invention can thus withstand substantial variations in temperature, humidity, or other environmental variables, without relaxation and without deterioration of its electrical properties. A specific advantage of the invention is thus that the maintenance of the crimped connection does not depend in any way upon the insulation film 4. In other words, if portions of this insulating film should relax and creep or flow, the contact at 36, in FIGURE 5, Would be maintained since this contact is entirely through metallic members, that is, the terminal and the conductor and does not have an insulating film contained between any of the compressed elements.
The number of lances provided and their size can be varied to suit the precise conditions encountered. Where relatively thin conductors 4 are provided in the cable, re-
latively smaller lances than those shown might be used and, for extremely short connectors, onlyone lanceneed be provided. The `connector in accordance with the invention, can, of course, be applied to an intermediate portion of the cable rather than to the end thereof thereby permitting the use of tap conductors with flat conductor cables ywhen desired. l
When the connector 8 is used with a-conductor `which is somewhat more narrow than the conductors shown in the drawing. The sides of the conductor may not be curled as shown in FIGURE 4. The connector can thus be used with conductors of varying width.
FIGURE 8 shows an alternative embodiment of the invention in which the sidewalls 16 are each provided with notches 40. These notches are desirable under some circumstances in that they provide relief for the plastic entrapped by the crimping operation. These notches are particularly desirable where the plastic insulating films are relatively thick.
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. The actual scope of the invention is intended to be `defined in the following claims when viewed in their proper perspective against the prior art.
What is claimed is:
1. An electrical connector intended for use with at conductor cable, said connector having a U-shapcd crosssection comprising a web and sidewalls, a lance struck from said web and disposed lbetween said sidewalls, said lance extends` otbliquely with respect to the plane of said Web, and stop means in said web adjacent to said lance for preventing said lance from being bent into coplanar relationship with said web, said stop means comprising a deformed portion of said web adjacent to. said lance, whereby after crimping said connector onto a conductor in a fiat conductor cable with said sidewalls s-traddling said conductor with said; sidewalls bent towards each other and `towards said web, said conductor isl pinched between said sidewalls and said lance, and said lance is held against said conductor by said stop means.
2. A device as set forth in claim 1 wherein said connector has a pair of spaced-apart lances.
3. A crimped electrical connection between a connector and. a conductor in a at conductor cable, said connector having a generally channel-shaped cross-section comprising a web and sidewalls extending from the sides of said web, a lance struck from said web andl extending from the same side thereof as said sidewalls, and opening in said web formed as a result of formation of said lance, portions of said web adjacent to said opening being deformed and extending in the plane of said web past the original confines of said opening and functioning as a stop to prevent movement of said lance back into the plane of said web, said connector being in straddling relationship to said conductor with said sidewalls extending through said cable, said sidewalls being re-versely curled towards each other and towards said web and pressing said conductor against said lances, said sidewalls and said lances penetrating said conductors to establish electrical contact therewith.
References Cited UNITED STATES PATENTS 8/1953 Berg 339-97 7/1965 `Sarazen 339-27