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. Pat. No. 4,602,831, issued Jul. 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.
U.S. Pat. No. 6,203,376, issued to Magajne et al. And assigned to the assignee of the present invention, describes a wafer connector that has a connector body portion with a strain relief member applied to the cables as part of the connector body portion. The strain relief member is a cable clamp having a series of grooves which receive the cables and particularly space them. An insulative material is molded over the tail portions and the cable clamp to form a connector with a cable clamp formed integrally with the body of the connector. One disadvantage of this connector is that, during the overmolding process, the dielectric material within the cable is compressed from the injection molding pressure. The molding material may bleed into the cable and collapse the dielectric and the internal shield wrapping, or it may escape from the end walls of the mold into the area between the cables leading to the connector. As a result, there is a high product scrap rate and reduced electrical performance due to shorts caused from the high molding pressure. The conductors are also difficult and slow to align in the correct position for termination.
The present invention is directed to an improved cable connector that overcomes the aforementioned disadvantages.
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 so that the positioning member forms part of the housing, and the positioning members having a structure that provides an effective “dam” or blockage to molding material to thereby prevent the molding material from bleeding out of the desired perimeter of the connector housing.
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 pre-selected spacing within an insulative connector housing, the contacts having tail portions that are maintained in alignment with each other in a pre-selected, single plane, the connector including a series of cables having individual signal and ground wires each one respectively terminated to the tail portions, the cables being held in a preselected spacing by a clamping, or positioning, member that is integrally molded to the connector housing and which serves as a strain relief for the cables exiting the connector housing.
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 ground 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 place as the signal contact tail portions. This coplanar configuration simplifies the process of attaching the cable wires to the tails.
The tail portions of the signal 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 over-molded, or “potted”, in order to extend the connector housing from its body portion over the conductors and the clamp member.
A cable clamp holds the cables and conductors in a preferred spacing and provides strain relief during the over-molding process and in the completed connector. The cable clamp in one embodiment 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. A stop is formed on the cable clamp with guides formed therein so that the conductors extend therethrough in particular alignment and the cable end is protected during the overmolding process. The clamp is inserted into the mold, after attachment to the cables and 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.
In the course of this description, reference will be made to the attached drawings in which:
As noted earlier, the present invention pertains to an improved connector. Such a connector is shown generally at 20 in FIG. 1. The connector 20 has an elongated body portion 22 that is formed from an electrically insulative material, and preferably a dielectric 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 therein so as to accommodate corresponding conductive pins of an opposing, mating connector, typically a backplane or pin header connector (not shown) in which an array of pins project outwardly therefrom. The rear portion 25 holds a plurality of multi-wire cables 27, each containing one or more wires 28.
As shown in
In 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 and which positions the cables in a side-by-side order as shown.
Each conductor has a respective wire guide 80 formed in the two halves 32a, 32b of the cable clamp 31. In this embodiment, three wire guides 80 are associated with each cable groove 34. Accordingly, each cable has three conductors in this embodiment. Each conductor extends through its respective guide 80 such that when the first and second half portions 32a, 32b are connected each conductor and guide 80 cooperatively seal the guide 80 and stop 78 such that the trimmed cable end s74 (
Each groove 34 preferably includes at least one transverse rib 82. In this embodiment, the first half portion 32a has two transverse ribs 82 formed therein and the second half portion 32b has three transverse ribs 82 formed therein. Each transverse rib 82 on the first half portion 32a is offset from each transverse rib 82 formed on the second half portion 32b. Such configuration cooperatively creates a tortuous path which not only grips the cable, but also provides strain relief.
The raised land portions 35 preferably include, as illustrated, means for orienting and mating the two halves 32a, 32b together such as alignment lugs 36 and corresponding recessed opening 37 for receiving the alignment lugs 36. The alignment lugs 36 and opening 37 are located in the wider interior lands, while the thinner, exterior lands may include alignment apertures 38 and notches 39. These sets of alignment 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 84 aptly serve as energy directors when ultrasonic welding or other similar means of joining is used.
In this embodiment, the stop 78 is partly formed on each of the two halves 32a, 32b. The distal end of each portion of the stop 78 formed on each half 32a, 32b defines an engaging complimentary contour. These engaging contours correctly align the halves 32a, 32b relative to one another. It is within the teaching of this invention that the stop 78 may also be integrally formed as a one-piece element on either of the two halves 32a, 32b such that the guides 80 are defined as bores through the stop 78, as illustrated in FIG. 10.
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, or the clamp may be formed by way of a long mold cavity within pairs of opposing mold blocks. 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 24, 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. The alignment apertures 38 and/or notches 39 may engage devices when placed in the mold to properly orient the cable clamp 31 for the over-molding process. The notches 39 may also be used to locate the wires when attaching them to the connector tail portions 58. Further, overmolding the alignment apertures 38 aids in integrating the cable clamp 31 into the connector 20 and with strain relief for the connector 20.
The cable clamp illustrated in
Turning now to
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 to allow the pins of the mold to hold the contact leg portions 58 in place during molding. 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. (
On the other side of the contact assembly 29, as illustrated in
The grounding plate 55 further extends toward the front face 60 of the contact assembly 29 as at 61, to provide beneficial signal isolation of the signal contacts 43. As illustrated in
In assembling the connector 20, the leads of the cable conductor wires 28 are attached to the tail portions 49, 58 in any suitable manner, such as adhering, welding or soldering. In this process, the conductor signal leads are preferably attached to their corresponding signal contact tail portions 49 and the conductor 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.
In one embodiment of the present invention, the cable clamp 31 may be applied to the wires 28 prior to their attachment to the contact assembly 29. In the second embodiment of
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 over-molded 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 over-molding occurs generally along the extent indicated at “OM” in
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 15; and cable assemblies 29, 30 in the mold cavity in as much 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 and as illustrated in
While the preferred embodiments of the invention have been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made to these embodiments without departing from the spirit of the invention, the scope of which is defined by the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
4602831 | Lockard | Jul 1986 | A |
4860445 | Jones | Aug 1989 | A |
5038001 | Koegel et al. | Aug 1991 | A |
5964620 | Takahashi et al. | Oct 1999 | A |
5990420 | Alexander | Nov 1999 | A |
6203376 | Magajne et al. | Mar 2001 | B1 |
6305978 | Ko et al. | Oct 2001 | B1 |
6726503 | Waddell et al. | Apr 2004 | B2 |
6758694 | Liu | Jul 2004 | B2 |