Cable wafer connector with integrated strain relief

Abstract: A wafer connector (20) for connecting cables (27) to a pin header has a connector body portion (22) that incorporates a strain relief member (31) applied to the cables as part of the connector body portion. The strain relief member includes a cable clamp (31) having a series of grooves (71) that are separated by intervening land portions (70). The grooves (71) receive the cables and space them in a particular spacing. The leads of the cable are terminated to corresponding tail portions (49,58) of contacts (43) of the connector. These tail portions are maintained in the same plane to enhance the electrical performance of the connector. An insulative material is molded over the tail portions (49,58) and the cable clamp (31) to form a connector with a cable clamp formed integrally with the body of the connector.

Description: Background of the Invention: The present invention relates generally to cable connectors, and more particularly to cable connectors used in high speed applications with a strain relief means integrated into the connector structure. Many connectors are known in the art for connecting cables to backplane assemblies. Most of these connectors are assembled from numerous components and include contact terminals, ground plates and housings. The contact terminals and ground plates and their points of connection to the cables are maintained in different planes, as exemplified by the connector construction described in U.S. Patent No. 4,602,831, issued July 29, 1986. The different planes of these termination points increases the difficulty in welding or soldering the cable leads to the termination tails of the connector and thereby increases the cost of manufacturing these connectors. Also, this double-plane arrangement lends itself to increased electrical interference between signal wires of the cable in the form of crosstalk. Additionally, prior art connectors utilize the strain relief members that are separately attached to the cables aft of and spaced apart from the connector body. The present invention is directed to an improved cable connector that overcomes the aforementioned disadvantages. Summary of the Invention: Accordingly, it is a general object of the present invention to provide an improved cable connector with enhanced electrical performance characteristics for use in cable wafer connector applications. It is another object of the present invention to provide a connector for connecting a series of cables to an array of conductive pins in which the individual wires of the cables are maintained and terminated in the same plane and in which the signal wires thereof are flanked by ground wires so as to enhance the electrical performance of the connector. A further object of the present invention is to provide a cable with connector assembly that enclosed a plurality of conductive pin contacts to which a number of individual wires are terminated, the wire terminations being effected in substantially the same plane to enhance the electrical performance thereof, the cables being spaced together by a cable positioning member, the connector assembly further having a housing that is molded over the positioning member. A still further object of the present invention is to provide an integrated cable connector having a plurality of signal and ground contacts maintained in a preselected spacing within an insulative connector housing, the contacts having tail portions that are maintained in alignment with each other in a preselected, single plane, the connector including a series of cables having individual signal and ground wires that one respectively terminated to the tail portions, the cables being held in a preselected spacing by a clamping member that is integrally molded to the connector housing and which serves as a strain relief for the cables exiting the connector housing. The object of the invention is achieved by subject matter of claim 1. In accordance with these objects, the present invention provides in one principal aspect an improved wafer connector structure having a connector body portion that supports, on one side thereof, a plurality of signal contacts and on another side thereof, a ground shield. The signal contacts and ground shield have tail portions that extend rearwardly of the connector body portion. In the preferred embodiment, the tail portions of the signal contacts are flat in their extent and lie in a common plane, while the tail portions of the ground signal shield are also flat and further are bent so that they lie in the same plane as the signal contact tail portions. This coplanarity simplifies the process of attaching the cable wires to the tails. The tail portions of the signals and ground contacts are arranged in an alternating fashion so that, if desired, each signal contact or pair of signal contacts may be surrounded by a ground tail portion so as to reduce the likelihood of crosstalk from occurring in the connector. In another important aspect of the present invention, the cable wire connection area is overmolded to extend the connector housing from its body portion over the cable ends. A cable spacer is provided in the form of a clamp or retainer that holds the cables in a preferred spacing for cable stripping and termination. This cable clamp also provides strain relief during the overmolding process and in the completed connector. The cable clamp takes the form of a two-piece insert that is applied to the cables and, in this regard, has grooves formed therein that receive the cables. The clamp is inserted, after attachment to the cables, into the mold and after termination of the wires to the tail portions. The extension of the connector housing is then molded over it, and the termination points of the cable wires, thereby joining the separate cable clamp and the contact assembly together into an integral connector body. These and other objects, features and advantages of the present invention will be clearly understood through consideration of the following detailed description. Brief Description of the Drawings: In the course of this description, reference will be made to the attached drawings in which: FIG. 1 is a perspective view of a wafer connector constructed in accordance with the principles of the present invention; FIG. 2 is an exploded view of a wafer subassembly and a set of wire-containing cables held by a cable clamp or retainer shown separated from the wafer subassembly; FIG. 3A is a top plan view of the wafer subassembly of FIG. 2 with a cable shown aligned and in contact therewith; FIG. 3B is a bottom plan view of the wafer subassembly of FIG. 2; FIG. 4 is a side elevational view of the assembly of FIG. 3 taken along lines 4-4 thereof; FIG. 5 is a top plan view of the wafer connector of FIG. 1 showing the position of the cables molded within the wafer connector body; FIG. 6 is a side elevational view of the wafer connector of FIG. 5 taken along lines 6-6 thereof; FIG. 7 is a perspective view of one portion of a cable clamp, or retainer, used in the wafer connector of FIG. 1; FIG. 8 is a perspective view of a cable clamp similar to that of FIG. 7 that has been applied to three cables and with the two half portions of the cable clamp joined together to maintain the cables in a particular position and spacing; FIG. 9 is a perspective view of another embodiment of the cable clamp of FIG. 8; FIG. 10 is a perspective view of another embodiment of a cable clamp used in wafer connectors of the present invention; FIG. 11 is an end view of the connector of FIG. 5, taken along line 11-11 thereof: and, FIG. 12 is an end view of the connector of FIG. 5 illustrating the front of the connector and schematically indicating one preferred arrangement of the signal and ground contacts in the connector. Detail Description of the Preferred Embodiments: As noted earlier, the present invention pertains to an improved wafer connector. Such a connector is shown generally at 20 in FIG. 1. The connector 20 has an elongated body portion 22 formed from an electrically insulative material, such as a plastic. The body portion 22 has defined front and rear portions 24, 25, with the front portion 24 including a plurality of conductive contacts 26 that are arranged in a preselected spacing so as to accommodate corresponding conductive pins of one opposing member (not shown) such as an array of pins that might be found projecting from a backplane member. The rear portion 25 holds a plurality of multi-wire cables 27, each containing one or more wires 28. As shown in FIG. 2, the cables 27 are aligned with their corresponding connector contact assembly 29 and then are attached thereto. The overall connector body portion 22 is subsequently molded over the contact assembly 29 and part of the cable assembly 30. Thus, the finished connector 20 may be considered as the union of two different, and separate assemblies: a contact assembly 29 and a cable assembly 30. Addressing first the cable assembly 30, a plurality of multi-wire cables 27 are held together in a preselected spacing by way of a cable clamp, or retainer 31 formed of a material compatible for overmolding, such as a plastic. FIGS. 7 & 8 illustrate two such cable clamps 31. The cable clamp 31 shown in FIG. 7 includes two opposing halves 32a, 32b that are designed for easy engagement with each other. In this regard, and as illustrated in FIG. 7, the cable clamp halves 32a, 32b has a series of grooves 34, with three such grooves 34 being illustrated, that are separated from each other by intervening land portions 35. The grooves 34 extend through the width W of the clamp 31. The cable clamp illustrated in FIG. 8 differs from the one illustrated in FIG. 7 in that it has a specifically configured exterior surface 72 with groove or valley portions 71 separated by intervening land portions 70. The land portions 35 preferably include, as illustrated, means for orienting and mating the two halves 32a, 32b together such as projecting posts 36 and corresponding recessed openings 37 for receiving the posts 36. These posts 36 and openings 37 are located in the wider interior lands, while the thinner, exterior lands may include projecting triangular-shaped lugs 38 with an associated and appropriately configured triangular groove 39. These sets of interengaging elements assist in holding the cables 27 in place therein and the two halves 32a, 32b together during assembly. The halves 32a, 32b are preferably fixed together by any suitable means, such as ultrasonic welding, plastics welding, heat welding, adhesives or the like. In this regard, the lugs 38 and corresponding grooves 39 not only ensure the proper alignment and mating of the clamp halves 32a, 32b but also serve as energy directors when ultrasonic welding or other similar means of joining is used. Importantly, the cable clamp 31 may be made in strips of varying length and then trimmed to a desired sublength L in order to fit the number of cables 27 needed in the particular connector application. Additionally, as will be explained in greater detail below, the clamp 31 is easily inserted into a mold and the finished connector body is molded over it. In its location proximate to the rear end 25 of the connector 20, when the final connector body is molded over the contact assembly 29, the clamp 31 serves as a strain relief for the cables 27 and also assists in defining a portion of the rear end 25 of the connector 20. Turning now to FIG. 3A, a contact assembly 29 used in the connector 20 is illustrated in a top plan view, and partially in section. The contact assembly 29 includes an insulative frame, or support member 40 that supports a plurality of individual conductive contacts 43 that may be stamped and formed, with each contact having a pair of contact arms 44 with contact faces, or points 45, that are disposed within channels and spaced apart from each other a preselected distance less than the width, thickness or diameter of a corresponding pin, or male contact member 46 (shown in phantom). In this manner, engagement of the contact assembly 29 with a like number of pins 46 will cause the contact arms 44 to spread slightly apart under urging of the pins 46. The contact arms 44 will engage the pins 46 at their contact faces 45 by virtue of their springiness and their initial closely-spaced configuration. Slots 60 may be formed in the front end 24 of the connector 20 that communicate with the channels 59 of the support member 40. these slots 60 communicate with and open at the front end 24 of the connector 20 so as to permit the entrance therein of conductive male contact members 46 of an opposing connector (not shown). Each contact 43 extends rearwardly and includes elongated leg portions 48 that terminate in tail portions 49. The leg portions 48, as are the contacts 43 in their entirety, are separate from the leg portions 48 of adjacent contacts 43 so that a single tail portion 49 is associated with a single contact 43. A separation member, illustrated in the form of a plate member 51 serves to hold the contacts 43 together in a preselected alignment within a like number of channels 59. Openings 52 may be provided in the plate member 51 and allow visual confirmation of the proper placement of the contacts 43 onto the plate member 51 as well as provide a means for testing the continuity of the individual contacts 43. The tail portions 49 of these "signal" contacts 43 extend past the rear face 53 of the plate member 51 for a specific distance to permit the leads from the cable wires 28 to be terminated to the corresponding tail portions 49. (FIG. 3A.) On the other side of the contact assembly 29, as illustrated in FIG. 3B, a grounding or shielding member, in the form of a conductive plate 55 is provided. This grounding plate 55 has a series of openings 56 formed therein that receive, in an interference-type fit, a like series of posts 57 disposed on the other side of the plate member 51. A plurality of tail portions 58 are formed with the grounding plate 55 (and may be stamped and formed from the same plate 55) and extend rearwardly therefrom and past the rear face 53 of the plate member 51. These tail portions 58 are oriented in a preselected pattern so that they extend within the intervening spaces between adjacent tail portions 49 of the signal contacts 43. The grounding plate 55 further extends toward the front face 62 of the contact assembly 29 as at 61, to provide beneficial signal isolation of the signal contacts 43. As illustrated in FIG. 4, the grounding plate tail portions 58 are bent in a slightly offset manner so that they are aligned with and preferably lie in the same plane as the contact tail portions 49. This coplanarity is illustrated in FIG. 12. This coplanar arrangement facilitates the welding, or soldering of the wire leads of the individual signal wires 28 and the grounding shields 80 of the cables 27. Additionally, this coplanar arrangement reduces crosstalk, or interference, between the signal contacts 43 because the grounding and signal contact tail portions 58, 49 are disposed at the same level, and not raised or lowered in an alternating fashion, as is present in the prior art, which arrangement induces some crosstalk. In assembling the connector 20, the leads of the cable wires 28 are attached to the tail portions 49, 58 in any suitable manner, such as welding or soldering. In this process, the signal leads are preferably attached to their corresponding signal contact tail portions 49 and the grounding shields are attached to their corresponding grounding tail portions 58 in an alternating signal-ground-signal-ground arrangement so as to ensure proper signal isolation. This is shown schematically in FIG. 12, with the signal wires of the cables 27 being attached to the contact tail portions 49 at "S" , and the grounding, or drain leads being attached to the grounding tail portions 58 at "G". The cable clamp 31 may be applied to the wires 28 prior to their attachment to the contact assembly 29. When attached, the clamp 31 helps to put the individual cables in a proper pitch for termination. The cable clamp 31 is spaced apart from the contact assembly 29 so that an intervening space is defined therebetween. The tail portions of the contact assembly 29 and the termination ends of the cable wires and grounding members extend into this intervening space. The cable clamp 31 and contact assembly 29 may then be inserted as an entire assembly into a mold and what may be considered as an insulative extension, or bridging portion 65, of the overall connector body portion 22 is overmolded onto the contact assembly and its associated plate member 51. This extension 65 is molded over the tail portions and the plate member 51. It also is molded over the cable assembly 30 and its associated cable clamp 31, and therefore interconnects the cable clamp 31 to the support member 40 in an integral manner. This overmolding occurs generally along the extent indicated at "OM" in FIGS. 3 & 4 and serves to encapsulate the leads of the cable wires 28 and their attached tail portions 49, 58. The additonal insulative material from which this extension or bridging portion is molded will fill the intervening space between the cable clamp 31 and the support member 40 and, in essence, encapsulate the termnations between the cable wires and grounding members and the tail portions 49, 58, During the assembly process, the cable clamp 31 serves as a strain relief member for the cables 27, as well as shutoff in a mold. It also assists in properly positioning the contact and cable assemblies 29, 30 in the mold cavity inasmuch as the rear face 33 of the clamp 31 may be placed in the mold cavity so that it may extend coincident with a rear wall of the mold cavity, as illustrated in FIG. 5. The resultant connector 20 integrates the cable clamp 31 into its body portion 22. To assist in this integration, the cable clamp 31 also may have exterior land portions 70 that are separated by intervening groove or valley portions 71. These valleys 71 will receive the molding material so that it bonds with the cable clamp 31 to result in a structurally sound connector body portion 22. Additionally, the exterior land portions 70 will serve to define part of the overall exterior surfaces 79 of the final connectors 20.

Claims: An electrical cable connector (20) with reduced interference characteristics, comprising: a connector support member (40) formed from an insulative material, the support member having first and second surfaces extending between opposing first and second ends; an electrical contact assembly (29) having a plurality of conductive signal contacts held on the support member (40) first surface, the signal contacts each having an associated rearwardly extending first tail portion (49) for termination to a signal wire (28); a common shielding plate (55) disposed on the support member (40) second surface, the shielding plate (55) having a plurality of rearwardly extending second tail portions (58) for termination to grounding wires (80) associated therewith, said first and second tail portions (49, 58) extending lengthwise past said support member (40) second end, characterized in that said shielding plate (55) second tail portions (58) and said contact first tail portions (49) are lying in a common plane for termination to said signal wires (28) and said grounding wires (80) in substantially the same plane. The cable connector (20) of claim 1, further including a plurality of cables (27) connected thereto, each of the cables including a pair of distinct signal wires and a grounding member, the cable signal wires and grounding member having termination ends respectively terminated to said contact assembly first and second tail portions (49, 58), said contact assembly first and second tail portions (49, 58) and cable signal wire (28) and grounding member (80) termination ends extending rearwardly of said support member (40) into an intervening space defined by a rear edge of said support member and a front edge of a clamp member (31) applied to said cables (27), said connector (20) further including a separate connector body portion (22) that interconnects said support member (40) and said clamp member (31) together, the connector body portion (22) filling said intervening space and encapsulating said said contact assembly first and second tail portions (49, 58) and cable signal wire (28) and grounding member (80) termination ends. The cable connector (20) of claim 2, wherein said connector body portion (22) is formed from an insulative material and is molded over portions of said support member (40) and said clamp member (31). The cable connector (20) of one of claims 1 to 3, comprising: a connector housing with said plurality of electrical conductive contacts (26,43) disposed therein; said electrical contact assembly (29) having said plurality of conductive signal terminals disposed on the support member first surface, each of the signal terminals having a contact portion and an elongated first tail portion (49) extending lengthwise therefrom and past said support member second end; a grounding assembly having said shielding plate (55) disposed on the support member second surface, wherein said plurality of second tail portions (58) extend lengthwise past said support member (40) second end; a plurality of cables (27) maintained in a spaced-apart relationship, rearwardly of said support member (40) by a clamp member (31), the clamp member (31) being formed from an insulative material, each of the cables (27) containing at least one conductor electrically connected to said first and second tail portions (49, 58), and a bridging portion (65) formed from an insulative material molded to said support member (40) and said clamp member (31), the bridging portion (65) extending between said support member (40) and said clamp member (31), said bridging portion (65) encompassing both at least a portion of said support member (40) and said clamp member (31), said bridging portion (65) joining said support member (40) and said clamp member (31) integrally together into said connector housing. The connector (20) as set forth in claim 4, wherein said connector housing (22) includes a rear wall through which said cables (27) extend, said connector housing rear wall being cooperatively formed by said part of said clamp member (31) and of said bridging portion (65). The connector (20) as set forth in one of claims 2 to 5, wherein said support member (40) and said clamp member (31) are separated by an intervening space and said first and second terminal tail portions (49, 58) are arranged in an alternating fashion in said intervening space such that each second tail portion (58) lies adjacent to a first tail portion (49). The connector (20) as set forth in one of claims 4 to 6, wherein said bridging portion (65) is molded over a portion of said support member (40), a portion of said clamp member (31) and said first and second tail portions (49, 58), said bridging portion (65) encapsulating said first and second tail portions (49, 58). The connector (20) as set forth in one of claims 2 to 7, wherein said clamp member (31) includes an elongated base portion extending for approximately a width of said connector housing, the clamp member (31) base portion having a series of grooves (34) formed therein, each of said grooves (34) accommodating at least a single cable (27) therein. The connector (20) as set forth in claim 8, wherein said clamp member (31) base portion includes first and second half portions (32a, 32b), the first and second half portions including means (36, 37, 38, 39) for orienting and mating said two half portions (32a, 32b) together. The connector (20) as set forth in claim 9 , wherein said orienting and mating means (36, 37, 38, 39) includes sets of opposing posts and opening (36, 37) formed in said two half portions (32a, 32b). The connector (20) as set forth in one of claims 8 to 10, wherein said base portion has an exterior surface (72) with a series of grooves (71) formed therein, said grooves (71) receiving a portion of said connector body portion (22). The connector (20) as set forth in one of claims 2 to 11, wherein said support member (40) includes a plurality of channels disposed on said first surface, each of said channels receiving one of said contacts therein, and said shielding member including a plate portion extending across said support member second surface. The connector (20) as set forth in one of claims 1 to 12, wherein the signal contacts are arranged in spaced-apart order proximate to said support member first end, said tail portions (49) of the signal contact members are arranged proximate to and extending past said support member (40) second end, said tail portions (58) of the ground contact member (55) are arranged proximate to and extending past said support member (40) second end, and comprising: a plurality of cables (27), each having at least one signal wire (28) with a signal wire termination end and one grounding member (80) with a grounding member termination end extending throughout a length of the cable (27), the cable signal wire termination ends being electrically connected to said signal contact tail portions (49) and the cable grounding member termination ends being electrically connected to said ground contact member tail portions (58) in a preselected pattern such that every signal wire termination end has at least one grounding member termination end adjacent thereto; a clamp member (31) applied to said cables (27) and spaced rearwardly of said support member (40) second end, said clamp member (31) holding said cables in a predetermined spacing; and, an insulative body portion (22) molded over at least part of said support member (40) and said clamp member (31) to cooperatively define a connector housing, the connector housing encapsulating said signal and ground contact tail portions (49, 58) and said cable (27) signal wire and grounding member termination ends, thereby insulating said signal and ground contact tail portions (49, 58) and said cable signal wire and grounding member termination ends from each other. The connector (20) as claimed in one of claims 2 to 13, wherein said clamp member (31) includes first and second interengaging half portions (32a, 32b), the half portions including a plurality of interior grooves (34) corresponding in number to a number of cables (27) of said connector, the interior grooves (34) being separated by intervening land portions (35), the land portions having means for engaging said first and second half portions together. The connector as claimed in one of claims 2 to 14, wherein said clamp member (31) includes first and second clamp portions (32a, 32b), each of the two clamp portions having a plurality of interior grooves (34) disposed therein, each of the grooves having a width sufficient to accommodate half of a single cable (27) therein, said land portions (35) including means (36, 37, 38, 39) for orienting and mating said first and second clamp portions (32a, 32b) together. The connector (20) as claimed in one of claims 2 to 15, wherein said clamp member (31) includes an exterior surface (72) having a plurality of grooves (71) disposed therein, the exterior grooves being separated by intervening land portions (70), the exterior land portions (70) forming part of said connector housing. The connector (20) as claimed in one of claims 2 to 16, wherein said clamp member (31) includes an end wall that forms part of an end wall of said connector housing, said clamp member (31) end wall being capable of engaging an opposing surface of a mold cavity. The connector (20) as claimed in one of claims 2 to 17, wherein said clamp member (31) two half portions (32a, 32b) include exterior surfaces (72), said clamp member half portions (32a, 32b) exterior surfaces serving to at least partially define portions of exterior surfaces of said connector body. The connector (20) as claimed in one of claims 2 to 18, wherein said clamp member (31) and said support member (40) are spaced apart from each other by an intervening space, both of said signal contact and ground contact tail portions (49, 58) and said cable signal wire and grounding member terminations ends extending into said intervening space, said body portion (22) extending between said support member (40) and said clamp member (31) and filling said intervening space to thereby encapsulate said signal and ground contact tail portions (49, 58) and said cable signal wire and grounding member termination ends.

Inventors: MAGAJNE MICHAEL, MISKIN MICHAEL, SEAMANDS ED, MAGAJNE, MICHAEL, MISKIN, MICHAEL, SEAMANDS, ED
Applicants: MOLEX INC, MOLEX INCORPORATED
Application year: 2000
Main classification: H01R4
IPC codes: H01R13