Connector for terminating communication cables

Abstract: A connector for terminating at least one pair of wires, the connector comprising a housing (104, 104') and at least one pair (A, B) of contacts (106, 108, 106', 108') mounted in the housing, each contact having an insulation displacing contact (IDC) blade portion (107, 107') arranged in a row along the housing, wherein each contact (106', 108') further comprises a capacitive coupling portion (200, 200') overlapping the respective other contact of the same pair (A, B).

Description: This invention relates to a connector for termination of electrical cabling and in particular electrical cabling for communication systems. The invention is especially applicable to the termination of twisted pair cables. A connector with all features of the precharacterizing portion of claim 1 is known from WO 88/13 902. As the data transmission rates rise in modern communication systems, the problem of cross-talk between adjacent signal pairs becomes quite large. Typically, signals are transmitted along a pair of wires where one of the wires carries the positive signal and the other carries the negative signal. In order to compensate for any interference, the two wires are typically wrapped to form a twisted pair so that any electronic interference will effect both of the wires equally and the signals carried therein. It is been recognised that in electrical connectors that carry high frequency signals there will be cross-talk between the connector contacts. US 5,186,847 utilises contacts that incorporate a cross-over to compensate for the capacitive and inductive coupling between adjacent contacts such that signal degradation is minimised. US 5,547,405 incorporates lateral extensions onto signal contacts such that a capacitor can be formed to compensate for any capacitance/inductance induced by data transmission through the contacts. While the transmission line has be constructed to minimise cross-talk by way of the twisting of the pair and the connector it self can be optimised to minimise the capacitive or inductive coupling between signal contacts, a problem still exists where the transmission line needs to be connected to the contacts of the connector. The reason this is a problem is that typically the twisted pair will need to be untwisted and the separate wires connected to each of the contacts. Over this untwisted distance, it is possible that the signal carried within these lines is adversely effected. It is an additional problem that any shielding that might have been provided about these signal lines must typically end where the separate lines travel to their respective contacts. Therefore, it would be highly desirable to provide a connector with reduced crosstalk. It would be desirable to provide a connector that enables the twisted pair to remain twisted as close as possible to their respective termination. In addition, as the termination must occur in the field, it is highly desirable that the termination be simple and easy to operate. Finally, as there are large quantities of these terminations, the termination should be inexpensive. Also, it would be highly desirable to accommodate any shielding that may be in the signal wire such that it can be brought to ground. Objects of this invention are accomplished by providing a connector according to claim 1. Further advantageous aspects of the invention are set forth in the claims, or will be apparent from the following description and drawings. The invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 shows a connector. Figure 2 is front perspective view of a housing and rear contact of the terminator of figure 10; Figure 3 is front perspective view of the assembly of figure 11 showing a front contact inserted therein; Figure 4 is front perspective view of the assembly of figure 3 showing a stuffer cap in the terminated position; Figure 5 is sectional view taken along line 5-5 of figure 7; Figure 6 is sectional view taken along line 6-6 of figure 7 ; Figure 7 is front perspective view of the assembly of figure 9 showing a shield thereabout; Figure 8 shows a top view of a pair of assemblies mounted adjacent each other; Figure 9 is an embodiment of a contact, particularly for use in assemblies mounted adjacent each other; Figure 10 shows an embodiment similar to figure 8 but assembled with the contact of figure 9, Figure 11 shows an assembly with an outer conductive shell and a stuffer in a pre-terminated position; Figure 12 shows the assembly of figure 11 in the terminated position; Figure 13 is an isometric view of the assembly of figure 12 viewed from the other side; Figure 14 is a perspective view with partial cross-section of yet another connector embodiment of this invention; Figure 15 is a perspective view of contacts of the embodiment of figure 14; Figure 16 is top plan view of the contacts shown in figure 15. With respect now to figures 4-7, a connector that according to the present invention will be described. A connector 102 includes a housing 104 having contacts 106, 108 therein where a stuffer 114 is provided for pushing wires (not shown) of the twisted pair into the respective contacts. The contacts 106, 108 have IDC blade portions 107 with respective IDC slots 136, 142. The wires are received in openings 110, 112 and an outer shield 116 is provided that generally surrounds the aforedescribed structure. A primary difference between the embodiment of the terminator 102 and the aforedescribed terminator 2 is that the present embodiment is generally rectangular in configuration whereby the wires which would be received in openings 110, 112 are horizontally adjacent as opposed to the previous embodiment where they are vertically adjacent. This allows a number of particularly advantageous features to be realised as apparent from the description below. With respect now to figure 2, the housing 104 will be described. The housing 104 includes a base 118 and a surrounding box-like shell. Above the base 118 the walls 120 of the box-like shell include guide groups 126 for guiding the stuffer gap 114 as will be described below and the inner surfaces 128 also co-operate to guide the stuffer cap 114. Positioning windows 130 are formed in the shell 120 in order to establish the pre-terminated and terminated positions. Additionally, tabs 132 are provided for locating the shield 116 thereabout. The inner contact 106 is received in an inner channel 133 of the base 118. A similar outer channel 135 is also formed in the base 118. As the shell 120 is not fully closed on one side, a channel 134 is formed along the base 118. The inner contact 105 includes a pair of plate section 135 with an IDC 136 therebetween having a lead-in cutting edge 138. The inner contact 106 further includes a connection portion 141 for connecting to a complementary component. With reference now to figure 3, the outer contact 108 is seen disposed within the outer groove 135. The outer contact 108 is configured generally according to the inner contact 106 where a pair of plates 143 and an IDC 142 is precedad by lead-in cutting edges 144. The outer contact 108 further includes an engaging portion 146 for mating with the complementary conductors. With reference now to figure 4, the stuffer 114 is shown in the terminated position. The stuffer 114 Includes lances 152 that are seen in the terminated opening 130. And guide ribs 150 positioned Within guide grooves 126. The stuffer 114 further includes a raised pedestal portion 151 between the open side walls of the shell 120 in order to carry a biasing tongue 158 therein. The stuffer 114 can be further viewed in figures 5 and 6. Additionally. In figure 5 it is apparent that advantageously a single stamping can be used for both the inner contact 106 and outer contact 108 by simply reversing the position. This reduces the numbers of parts that need to be manufactured and thereby reduces costs. With respect now to figure 7, the shielding shell 116 is shown fixed to the structure of figure 4 by way of mounting tabs 132. As a result of moving the stuffer 114 into the terminated position, the tongue 158 associated therewith moves free of resilient free ends 169 of the shielding shell 116 allowing their natural resiliency to close about an inserted cable in order to form an electrical connection with the shielding as was previously described. Advantageously then, this embodiment provides a reduction in the number of parts required by enabling a single contact stamping to be used for both of the contacts. Additionally, In the construction of components of the base 104 and stuffer 114 are also simplified. Additionally the pair can be cut to the same length. Moreover, when pair connectors are placed side by side, mainly due to space constraints on amount of energy flows from one pair connector to the adjacent one. This energy flows via the parasitic capacitor that appears between the contacts of pair connector A and pair connector B, whereby the value of this parasitic capacitor is inversely proportional to their distance. Figure 8 shows two pair terminator placed side by wide where the distance Y (distance from contact 106 of pair connector A and contact 106 of pair connector B) is much higher than the distance X (distance from contact 106 of pair connector A and contact 108 of pair connector B). Thus the two parasitic capacitors have different values. The energy that flows from the contact 106 of pair connector A to the contact 106 of pair connector B is lower than the energy that flows from the contact 106 of pair connector A to the contact 108 of pair connector B. As result the residual noise between the contact 106 and contact 108 of pair connector B is greater than zero and will affect the high frequency performance of the pair connector B. The same relation and results are valid for other combinations of contacts for two adjacent pair connectors. A solution to this problem foresees the addition of a capacitive coupling portion area 200 to the contact, as shown in figure 9. This overlapping portion is used to compensate the noise from one pair connector to the other. Figure 10 shows two pair connectors placed side by side where the distance Y (distance from contact 106 of pair connector A to coupling portion 200 of contact 106 of pair connector B) is nearly equal to the distance X (distance from contact 108 of pair connector A to contact 108 of pair connector B). This the two parasitic capacitors have very similar values. The energy that flows from the contact 106 of pair connector A to the coupling portion 200 of the contact 106 of pair connector B is nearly equal to the energy that flows from the contact 106 of pair connector A to the contact 108 of pair connector B. As result the residual noise between the contact 106 and contact 108 of pair connector B is nearly equal to zero, so the high frequency performance of the pair connector B is increased. In addition, the overlapping of contacts of the same pair have a similar effect to twisting (wire) conductors, thereby reducing electromagnetic noise emission and reception. The same relation and results are valid for other combinations of contacts and additional areas for two adjacent pair connectors. Figure 11 shows a pair connector with an outer metallic shell 216 and the stuffer 214 in the pre-terminated position. The metallic shell 216 has two deflectable arms 268 placed below the openings 210 and 212. Due to their elasticity the arms 268 will provide a normal force on the conductive foil or on any other type of shielding around the pair. The stuffer in the terminated position (figure 12) reacts the normal force from the arms 268 via the feature 300. The shielding can be drained by way of contact legs 270 that would also be fixed to traces of a printed circuit board or similar contacts. Figure 13 shows the metallic shell 216 that surrounds the housing 204 and is retained on it via the tabs 232. Referring to figures 14-16, another embodiment of a connector according to this invention is shown comprising a housing 104' and two pairs A, B of contacts 106', 108'. The housing may be provided with a plurality of contact pairs greater than two. The connector embodiment of figures 14-16 differs from the embodiment shown In figures 8 and 10 in that the plurality of contact pairs are provided in a single housing, which renders the design more compact and cost-effective. Similar to the previously described embodiment, the contacts 106', 108' of a same pair have overlapping capacitive coupling portions 200' for the same purpose as the portions 200 of the previously described embodiment. In the embodiment of figures 23-25, the overlapping portions 200' extend in a plane parallel to the IDC blade portions 107', but spaced therefrom such that the IDC blade portions 107' of the plurality of contacts 106', 108' are positionable in substantially the same plane. As in the previous embodiment, the capacitive coupling portions 200' may be integrally stamped and formed with the IDC blade portions 107' of the contacts. The plurality of contacts 106', 108' may be identically formed whereby the contacts 106', 108' of a pair A, B are rotated with respect to each other 180°. In the embodiment of figures 14-15, conducting wires W are received in open ended slots 110', 112' of the housing that guide the wires into the IDC blade slots 136', 142'. The wires may be inserted in the slots by means of stuffer tool, or the housing may be further associated with a cover member that stuffs the wires into the slots in a similar manner to the previously described embodiments.

Claims: A connector for terminating at least two pairs of wires, the connector comprising at least one housing (104, 104') and at least two pairs (A, B) of contacts (106, 108, 106', 108') placed side by side, each pair mounted in a housing, each contact having an insulation displacing contact (IDC) blade portion (107, 107'), each contact (106, 106', 108, 108') further comprising a capacitive coupling portion (200, 200') overlapping the respective other contact of the same pair (A, B), the contacts (106, 108, 106', 108') being identical to each other, characterized in that the distance (Y) from the first contact (106, 106') of a first pair (A) to the capacitive coupling portion (200, 200') of the first contact (106, 106') of a second pair (B) is nearly equal to the distance (X) from first contact (106, 106') of the first pair (A) to the second contact (108, 108') of second pair (B). The connector of claim 1 wherein each contact pair is provided in a single housing. The connector of claim 1 wherein the at least two contact pairs are provided in a single housing. The connector of any one of the preceding claims wherein the capacitive coupling portions (200,200') extend integrally from the IDC blade portions (107, 107'). The connector of claim 1 wherein the IDC blade portions (107') of the connector are parallel to each other. The connector of any one of the preceding claims wherein the connector comprises a stuffer (114) having a pair of openings (110, 112) for receiving wires and positioning them relative to the IDC contacts (106, 108) the stuffer being receivable by the housing (104) and moveable therein between a pre-terminated position and a terminated position. The connector of claim 1 wherein the IDC contacts (106, 108) of a pair are staggered with respect to each other. The connector of any one of claims 1-6 wherein the IDC blade portions (107') are arranged in the same plane. The connector of claim 8 wherein the coupling portions (200') are arranged in a plane offset from the IDC blade portion (107').

Inventors: COLOMBO MASSIMO, PRIGIONE PAOLO LORENZO, COLOMBO, MASSIMO, PRIGIONE, PAOLO LORENZO
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1999
Main classification: H01R24
IPC codes: H01R24, H01R4