Patent Publication Number: US-3879099-A

Title: Flat fexible cable connector assembly including insulation piercing contacts

Description:
O United States Patent 11 1 1111 3,879,099  
 Shaffer Apr. 22, 1975 [54] FLAT FEXIBLE CABLE CONNECTOR 3.825.881 7/1974 Wigby 339/97 R ASSEMBLY INCLUDING INSULATION D232.556 8/1974 Michel et al. DZb/l R PIERCING CONTACTS FOREIGN PATENTS OR APPLICATIONS Inventor; Howard Richard Shaffer l.394.87l 3/l965 Francc 339/208 Harrisburg p 544.048 1/1956 Belgium 339/99 R 1.200.801 8/1970 United Kingdom 339/176 MF [73] Assignee: AMP Incorporated, Harrisburg. Pa. 22 Filed: s 1973 Primary Examiner-Roy D. Frazier Assistant Evaminer-Lawrence I. Staab PP NOJ 394562 Attorney, Agent, or Firm-Russel J. Egan. Esq.  
 1521 US. Cl 339/99 R; 339/107; 339/138; 1571 ABSTRACT 339/176 MP A connector assembly is disclosed for terminating [51] Int. Cl Hlr 11/20; H01r 13/58 multi-eonductor fl fl xi l cable i h contacts which [58] Field of Search 339/ 17 F. 97-99, pi r e the cable insulation to make good electrical 339/103 C, 103 M, 105, 107, 139, 141, 142, and mechanical engagement with all types of cable 176 MF, 174, 206, 208, 210 conductors, in particular round wire and stranded wire. Each contact is die stamped from sheet material [56] References Cit d and has a body portion with a pin or socket electrical UNITED STATES PATENTS termination means extending from one side and a pair 1,956,018 4/1934 Gilbert 339 99 R of Space? arms exlendmg P mother 849 V1941 Thompson 9/97 R X ver fashion. Forked pro ecnons extend from the free 5334:2181 /1950 schmcaaliiiili iiiii :11: 339 97 R x and of each and are angulml) Offset with respect 2.603.679 7/1952 Pavlinctz 339/97 c to both the Plane of the Contact and to one another in 2.673.968 3/1954 Smith 339/99 R d r t ngage in an interdigitated fashion. The con- 2.790.153 4/1957 Arson 339/139 C X nector assembly includes a multi-part housing includ- 3.148.928 9/1964 Noschesc ct al. 339/103 M ing a ontact block mounted in a housing Shell and Dcan P two housing members pivotally mounted in the 3 3 1 housing shell and adapted close the contacts on an as u t 3.399.373 8/1968 Maki ct al. 339/217 R X sociated cable and provrdestram rellef for the cable. 3.820.058 6/1974 Fricnd 339/99 R 20 Claims, 9 Drawing Figures a 7 l 22 52 a FLAT FEXIBLE CABLE-CONNECTOR ASSEMBLY INCLUDING INSULATION PIERCING CONTACTS BACKGROUND OF THE INVENTION 1. The Field of the Invention The present invention relates to an improved multiconductor flat flexible cable connector assembly andin particular to an .insulation piercing contact capable of making good mechanical and electrical engagement with all types of conductors, including round wire and stranded wire.  
 2. The Prior Art There are many problems involved in providing good electrical termination for flat flexible cable. particularly cable havinground wire or stranded wire conductors. Most of the known termination methods and contacts have required some sort of insulation stripping or other cable preparation prior to attaching the contacts. Many of the known contacts that can be applied directly through the cable insulation have not been able to provide satisfactory mechanical and electrical engagement with the conductors of the cable. This has been the case particularly in instances when the cable conductors are round wires or stranded wires. Insulation piercing contacts have displayed a tendency to unwind stranded wire, so that good mechanical engagement cannot be made, and to sever either the round or stranded wire with the obvious deleterious effects to the cable.  
 SUMMARY OF THE INVENTION The subject connector assembly has aplurality of insulation piercing contacts. Each contact includes a base portion having a pin or socket extending from a first side and a pair of cantilever beams extending from another side. A forked projection on the free end of each cantilever arm is directed toward the other arm and is angularly offset with respect to both the other forked projection and the plane of the contact so that they pierce the cable insulation within each others slotv in interdigitated fashion. The connector housing includes a contact receiving block and two mating housing members pivotally attached to the receiving block and frictionally engaging the arms of each contact. Each mating housing member also has intercngaging locking means and cable strain relief means.  
  It is an object of the present invention to construct an insulation piercing contact and connector assembly which can be used to terminate multi-conductor flat flexible cable and which can be applied to said cable without special tooling.  
  It is another object of the present invention to produce an insulation piercing contact and connector assembly for use in terminating multi-conductor flat flexible cable in which the contacts pierce the insulation of the flat flexible cable during the attachment of the connector thereto and make good electrical and mechanical engagement with the cable conductors.  
  It is a further object of the present invention to construct an insulation piercing contact and connector assembly for terminating flat flexible cable having round conductors of either the single or multi-strand type.  
  It is yet another object of the present invention to produce an insulation piercing contact and connector assembly which may be used to terminate flat flexible cable and is mateable with similar existing terminal connectors.  
  The foregoing and other objects of the present invention will become readily apparent to those skilled in the art from the following detailed description taken with reference to the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the subject connector assembly fixed to one end of a multi-conductor flat flexible cable;  
  FIG. 2 is a vertical section through the subject contact and connector assembly in the open condition ready to be attached to a flat flexible cable;  
  FIG. 3 is a vertical section. similar to FIG. 2, showing the subject contact and connector assembly secured to one end of a multi-conductor flat flexible cable:  
  FIG. 4 is a perspective view of a segment of the upper mating housing member with a portion of a single contact inserted therein;  
  FIG. 5 is a side elevation of a single contact according to the subject invention;  
  FIG. 6 is a top elevation of the subject contact shown in FIG. 5;  
  FIG. 7 is a perspective view showing the engagement of two contacts with conductors at one end of a segment of multi-conductor flat flexible cable;  
  FIG. 8 is a schematic horizontal section through a single conductor of a flat flexible cable showing the engagement of a contact therewith; and  
  FIG. 9 is a detail view of a portion of the subject housing showing mating locking means.  
 DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The subject connector assembly 10 is shown in FIG. 1 attached to and forming the termination of a multiconducto&#39;r flat flexible cable 12. The connector assembly 10 includes a two part housing shell 14, a contact block 16, a pair of mating housing members I8, 20 and a plurality of contacts 22. Each contact 22 includes a body portion 24 with a pin (as shown) or socket electrical connection terminal 26 extending from one side and a pair of diverging cantilever arms 28, 30 extending from another side. A forked insulation piercing projection 32, 34 extends from the free end of each arm 28, 30. respectively, at an angle substantially normal to the plane of the cable 12 to be received therein. Each forked projection 32, 34 is also angularly offet with respect to the other forked projection and the plane of the contact (see FIG. 6) so that the tines of the forked projections form an interdigitated configuration when the arms 28, 30 are brought together. A friction fastening lance 36 projects laterally from one side of the body portion 24.  
  The metallic housing shell 14 encloses the contact block 16 and has a forwardly directed hood portion 38, which surrounds and protects the electrical connection terminal 26 of each contact 22, and a rear shell 40 secured to the hood portion by tabs 42. The rear shell 40 includes inwardly directed arcuate flanges 44, 46 which, together with the rear portion of the contact block 16, define upper and lower channels 48 and 50, respectively. The contact block 16 has a plurality of bores 52 extending from the front face 54 and a plurality of slots 56 extending from the rear face 58. Each slot 56 communicates with a respective one of the bores 52. The pairof mating housing members 18, 20 each have an arcuate lip portion 60, 62 adapted to be received in the upper and lower channels 48, 50, respcctively.  
  The embodiment of the subject connector shown in FIG. 1 is asymmetric with the top being somewhat longer than the bottom. For this reason the upper mating housing member 18 is longer than the bottom mating member and is provided with a central keying aperture 64 which mates with a keying projection 66 on the upper rear end of contact block 16 thus keying the mating housing members for proper assembly. The mating housing members are provided with interengaging. transversely extending strain relief projections 68, 70. and 72. They are also provided with interengaging locking means 74, 76. One portion of the locking means, in this case the lances 76, are so spaced as to guide the cable so that the proper conductor 78 is aligned with the proper contact 24.  
  Each of the mating housing members also has a plurality of contact receiving recesses 80 (see FIG. 4) in which the arms 28 and 30 of each contact are frictionally received. Each recess 80 includes an arm channel 82 and an enlarged profiled end recess 84. The channels 82 are of two different lengths so that the adjacent enlarged profiled end recesses 84 are offset thus allowing the contacts to be more closely spaced.  
  The subject contact and connector are assembled in the following fashion, the receptacle block 16 is preloaded with a plurality of contacts 22 with the electric connection terminals 26 projecting from the front face 54. The hood portion 38 and rear portion 40 of the housing shell 14 are assembled over the preloaded contact block 16 and secured together by tabs 42. The mating housing members 18 and 20 are pivotally attached to the assembly by inserting lip portions 60, 62 into the upper and lower channels 48, 50, respectively. The arms 28, 30 of the contacts 22 are frictionally engaged in the recesses 80. The friction developed between the plurality of contact arms and the mating housing members is sufficient to hold the mating housing members in the assembly in this open position. The thus completed assembly is shipped in this fashion and subsequently assembled with a flat flexible cable by inserting the cable between the open mating housing members 18, 20 and between the spread contact arms 28, 30, as shown in FIG. 2. When the cable 12 is fully inserted into the housing, the mating housing members 18, 20 are brought together until the locking means 74, 76 engage and the strain relieving members 68, 70, and 72 grip the cable 12.  
  As the mating housing members 18 and 20 are brought together, they engage and drive the arms 28, 30 of the contacts 22 together, the shorter contact arms being engaged and moved first. The closing movement of the arms causes the lance shaped ends of the forked projections to pierce the insulation of the cable and form a closed substantially oval configuration surrounding the conduetors of the cable so that they will all be firmly engaged as shown schematically in FIG. 8. It will be noted that the arms 28, 30 have been shown with a bend intermediate their connection to the contact body 24 and forked projections 32, 34, respectively. The purpose of this bend, as mentioned above, is to align the forked projections so that they are normally substantially perpendicular to the plane of the cable and will follow a more or less straight line as the penetrate the cable insulation. This additional bend is optional and the same function can be accomplished by appropriate adjustment of the geometry of the arms and forked projections.  
  The forward edges 86 and 88 of the mating housing members 18 and 20, respectively, are preferably disposed to lock contacts 22 in the contact block 16 when the members are themselves locked together. This locking of the contacts against movement is in addition to that accomplished by the arms 28 and 30 being retained in slots 80.  
  The subject contact and connector assembly provide a ready means of attaching terminals to flat flexible eable, including the cables with round connectors. The connector assembly allows for all contacts to be engaged with the cable at one time and with a single motion. No tools or special equipment is required to effect the connection and pin and socket patterns can be arranged for mating with existing connectors. The contacts are insulation piercing so that there is no requirement for stripping or separation of the wires. The cable is tightly gripped between the portions of the housing so that there is a provision for strain relief of the cable.  
  The forked projections of the subject contact pierce the cable insulation from opposite sides of the conductor. The forked projections have an angular displacement with respect to each other so that they pierce within each others slot. The result is that when the conductors are engaged from opposite sides, movement of the conductor is controlled preventing the conductor from being bent or severed or, if it is a stranded wire conductor, becoming untwisted or separated. The result is a good penetration by the forked projections and good contact control between the conductors and the contact.  
  One of the problems in making a connector assembly for terminating flat flexible cable and still mating with existing connectors is the difference between the centerline distances of the cable conductors and the contacts. In one case the difference may be minimal and wherein another case it may be a critical factor. This means that the contacts may not be aligned with the conductors in all cases. In order to overcome this, the two mating halves of the connector housing may be designed with the contact slots diverging toward the free end. The contacts thus can be positioned directly over each conductor of the cable while providing the desired spacing of the contacts.  
  The latching means shown in FIG. 9 is but an example of one satisfactory means for effecting the desired locking of the mating housing members and guidance for aligning the cable. It is quite clear that other locking means, including C shaped metal clamps fitting exter nally over the housing members, would be equally as acceptable. The cable guidance function could likewise be accomplished by edge tabs or flanges on one of the mating housing members.  
  The present invention is subject to many modifications and&#39;variations without departing from spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as merely illustrative and not restrictive.  
 What is claimed is:  
  1. An insulation piercing contact for making good electrical and mechanical engagement with an associated insulated conductor, comprising:  
 a planar body portion,  
 a matablc electrical connection member extending from one side of said body portion;  
 a pair of cantilever arms extending from another side of said body portion and lying substantially in the plane of said body portion;  
 a forked projection on the free end of each of said arms, each said forked projection including at least two tines defining a plane. said forked projections being directed towards one another with their respective planes intersecting by being angularly offset with respect to both each other and to the plane of said body portion whereby bringing said arms together causes said tines of said forked projections to come together in interdigitated fashion to pierce the insulation of an insulated conductor and entrap the conductor therebetween.  
 2. The contact according to claim 1 wherein said cantilever arms diverge from each other.  
  3. The contact according to claim 1 wherein said forked projections are substantially perpendicular to the axis of the conductor engaged thereby.  
  4. The contact according to claim 3 wherein said cantilever arms have a bent configuration in the plane of said body portion and intermediate the ends thereof whereby said forked projections follow a substantially straight path as said arms are brought together.  
  5. The contact according to claim 1 further comprising:  
 at least one locking lance extending from said bodyportion transversely of the plane thereof.  
  6. The contact according to claim 1 wherein said matable electrical connection member is a socket.  
  7. The contact according to claim 1 wherein said matable electrical connection member is a pin.  
  8. A connector assembly for terminating flat flexible cable having a plurality of insulated conductors comprising:  
 a contact block having a plurality of through passages therein,  
 a like plurality of contacts each positioned in a respective one of said passages, each said contact including a planar body portion, an electrical connection terminal extending from one side of said body portion, a pair of cantilever arms extending from another side of said body portion and lying substantially in the plane thereof, a forked projection at the free end of each said arm, each said forked projection including at least two tines defining a plane, said forked projections being directed towards one another with their respective planes intersecting by being angularly offset with respect to each other and the plane of said body portion,  
 and a pair of mating housing members pivotally attached to said contact block and adapted to act against said arms to bring said projections into interdigitated engagement with conductors of said flat flexible cable entrapped and engaged by said tines.  
 9. A connector assembly according to claim 8 further 6 comprising:  
 a housing shell surrounding said contact block. said shell including a hood portion having a forwardly directed flange encompassing and protecting said electrical connection terminals, a rear portion, and means securing said two portions together.  
  10. A connector assembly according to claim 9 wherein said rear portion of said housing shell and said contact block define upper and lower channels,  
 each said mating housing member having an arcuate flange adapted to engage in a respective one of said channels whereby said members are pivotally attached to said connector block.  
  11. A connector assembly according to claim 10 wherein said mating housing members are of different transverse widths,  
 further comprising keying means on the arcuate flange of the wider of said members and the associated channel preventing the insertion of the narrower member into the keyed channel.  
 12. A connector assembly according to claim 11 wherein said keying means comprises:  
 a slot formed in the arcuate flange of said wider member, and  
 a fixed stud formed in said wider channel.  
  13. A connector assembly according to claim 8 further comprising:  
 a plurality of grooves in adjacent faces of said mating housing members, each groove adapted to frictionally engage respective arms of said contacts.  
  14. A connector assembly according to claim 13 wherein each said groove has an enlarged portion at the blind end adapted to receive the angled forked projection of the associated contact.  
  15. A connector assembly according to claim 8 further comprising:  
 strain relief means on said mating housing members.  
  16. A connector assembly according to claim 15 wherein said strain relief means comprises a plurality of interfitting transverse ridges on mating surfaces of said mating housing members forming a tortous path therebetween.  
  l7. A connector assembly according to claim 8 further comprising:  
 locking means adapted to secure said mating housing members together in a closed condition.  
  18. A connector assembly according to claim 17 wherein said locking means are integral with said mating housing members.  
  19. A connector assembly according to claim 18 wherein at least a portion of said locking means is profiled to serve as guide means for the cable.  
  20. A connector assembly according to claim 8 further comprising:  
 a contact locking ridge extending transversely on each side mating housing member and adapted to lie closely adjacent a rear surface of said contact block when said members are in a closed condition.