US 3237146 A
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Description (OCR text may contain errors)
Feb. 22, 1966 BARKER 3,237,146
TERMINAL Filed Aug. 9, 1963 1 66 INVENTOR. 72 1 I I f RANDOLPH e. BARKER I I I I BY United States Patent 3,237,146 TERMINAL Randolph G. Barker, 44 Ellis Ave., West Bridgewater, Mass. Filed Aug. 9, 1963, Ser. No. 301,164 7 Claims. (Cl. 339-14) The present invention relates to a terminal for a cable and is particularly useful with cables for high frequency signal transmission purposes.
Heretofore, there has been substantial difficulty in minimizing cross talk between pairs of twisted leads or wires in a cable used in connection with high frequency apparatus such as memory circuits, computers, digital control devices and the like. Because of very high frequencies used, and the consequent fast rates of rise of electrical signals in such components, means are necessary to avoid cross talk in such cables and particularly at the terminals of such cables. Heretofore, cables comprising a plurality of twisted pairs of leads or wires normally have one of each of such pairs connected to a pin in a terminal, with the other of each of such pairs of wires connected to ground at a distance from the one wire to pin connection. While the other of such wires in each pair may minimize or reduce cross talk along most of the length of the twisted pair, the short distance between the point at which the other of such leads is connected to ground and the pins is critical in many applications, be-
cause the untwisted distance, while short, is sufiicient to 4 cause cross talk and consequent interference between signals carried on adjacent wires.
It is therefore an object of the present invention to provide a terminal for a cable comprising a plurality of twisted or intertwined pairs of leads or wires in which one of each pair is normally used as a signal transmitting wire and the other wire serves as a ground wire. Each signal carrying wire is connected to a suitably mounted pin with these pins arranged for insertion in a complementary electrical receptacle. The other wires are each connected to a ground plate which is formed with a plurality of holes, through which the pins project in insulated relation with respect to the ground plate. Suitable connection means are provided to the ground plate, preferably for grounding the plate through the electrical receptacle.
These and other objects and advantages of the present invention will be more clearly understood when considered in conjunction with the accompanying drawings, in which:
FIG. 1 is an elevational view of a preferred embodiment of the invention,
FIG. 2 is a cross section taken along the line 2-2 of FIG. 1,
FIG. 3 is a bottom view,
FIG. 4 is a cross sectional view taken along the line 4-4 of FIG. 3 with portions omitted for clarity, and,
FIG. 5 is a top view of the ground plate element forming a portion of the invention.
The coaxial cable may be of any conventional type and comprises an outer casing 12 of any suitable flexible insulating material. A plurality of twisted or intertwined pairs of leads or wires, 14, 14a; 16, 16a; 18, 18a; 20, 20a; 22, 22a; etc., are contained within the casing 12 and project beyond its end 24 into the terminal casing 26. The terminal casing 26 may be formed in any convenient shape but preferably is formed with opposite walls 28 and 30 which are continuous with one another through walls 32 and 34. A shoulder portion is formed in the casing by the angular wall portion 36. The bottom and top of the casing are closed, respectively, by wall portions 38 and 40. The cable 10 may be secured by suitable means to the terminal casing 26. Such means may be provided by 3,237,146 Patented Feb. 22, 1966 an opening in the wall 30 through which the casing 12 projects in spaced relation to the periphery 42 of the hole in the wall 30. A sleeve 44 which is cemented or otherwise suitably secured to the cable 12 is provided with an annular shoulder section 46 adjacent one end. This shoulder section 46 interengages the periphery 42 of the hole through which the cable 10 projects and thereby locks the cable 16 in the hole. The sleeve 44 may be formed of any suitable material, but preferably is formed of the same material as the cable casing 12.
The wires 14, 14a; 16, 16a; etc., are bent angularly downward from the end of the cable 10, as viewed in FIG. 2. Each of these wires is insulated and is maintained in close adjacency to the other wire of its pair. This relationship is maintained along the length of the cable by twisting the pairs. Where the pairs project from the end 24 of the casing 12, the relationship of each pair may be further maintained by individually binding the wires of each pair together near their ends by segments of insulating tape 48 or other suitable means.
One wire in each of these pairs is normally used as a signal transmitting wire. These signal transmitting wires 14, 16, 18, etc., are connected at their ends, individually, to corresponding pins 54, 56, 58, 60, 62, etc., by suitable means, such as solder joints, illustrated at 64. Each of these pins 54, 56, etc., is rigidly secured in an insulating block 66 made preferably of a suitable plastic material. This rigid block is preferably coextensive with the inner side of wall portion 38, and secures the pins 54, 56, etc., rigidly and in parallel relationship with one another, The inner end of the pins project upwardly above the top surface of the insulating block 66, as viewed in FIG. 2, and downwardly through openings in the wall 38, with the free ends of the pins which project downwardly beyond the wall 38 adapted to be engaged by a complementary and suitable electrical receptacle. The inner ends of the pins and the adjacent portions of the signal wires 14, 16, etc., to which they are secured may be covered and insulated from the adjacent wires by insulating sleeves 70.
The other wires 14a, 16a, 18a, 26a, 22a, etc., of each of the twisted pairs are connected to a ground plate 72 (FIGS. 2 and 5). This ground plate 72 is rectangular in form and is provided with a plurality of holes or perforations 74. The ground plate is also provided with a plurality of ground connectors 76 which are formed of tubular conductive members that are secured to the plate 72 and project through it. The ground plate is also provided with at least one, and preferably two, ground pins 78. These ground pins 78 are formed of conductive material, preferably similar to the pins 54, 56, etc. The pins 78 are electrically connected to the ground plate 72 with portions extending on either side of the plate 72. Preferably, these pins are located at the ends of the plate 72 as viewed in FIG. 5.
The ground plate 72 is positioned within the insulating block 66 intermediate its upper and lower surfaces, as viewed in FIG. 2. The pins 54, 56, 58, etc., project respectively, one through each of the holes 74 and in spaced insulated relation to the plate 72. The ground connectors 76 project upwardly between the pins 54, 56, etc., terminating above the upper surface of the insulating block 66, as viewed in FIG. 2, and preferably in the same plane as the top of pins 54, 56, etc. The lower ends of the ground connectors 76 terminate prefarably within the insulating block 66.
The ends of the other wires 14a, 16a, 18a, etc., are suitably connected, preferably by soldering, one each to the other end of a ground connector 76. Preferably each of the other wires 14a, 16a, 18a, etc., is connected to the ground connector 76 adjacent to the pin which is connected to the signal wire of that particular pair.
The ground pins 78 project downwardly through the wall 38 and terminate preferably in the same plane as pins 54, 56, etc. The terminal may be connected to any suitable and complementary electrical receptacle for transmission of multiple signals in computer devices and the like. In such an arrangement, any signals induced in the ground wires from the signal wires of each pair are conducted through the ground plate and grounding pin to a suitable ground connection in the electrical receptacle.
While the foregoing description relates primarily to a terminal for cables having pairs of twisted leads, it may also be used in connection with cables formed of a plurality of shielded leads. In such an arrangement the inner or signal conductor of each shielded lead is the equivalent of leads 14, 16, 18, etc., and may be connected to the pins 54, 56, etc. The outer or grounded conductor of each shielded lead is the equivalent of leads 14a, 16a, 18a, etc., and may be connected to the ground connectors 76 of the ground plate 72. This arrangement is useful, for example, in minimizing cross talk and significantly improving the signal to voice ratio in the signal conducting wires.
The foregoing description is exemplary of a preferred embodiment of this invention and may be varied in accordance with known practices and is to be construed as limited only by the claims appended hereto.
What is claimed is:
-1. In combination with a cable for high frequency electrical signal transmission having a plurality of pairs of intertwined insulated wires,
a terminal comprising a plurality of pins with the ends of one of each of said pairs of wires connected to different ones of said pins,
insulating means comprising a rigid block securing said pins intermediate their ends in spaced parallel arrangement with corresponding ends of said pins projecting beyond one surface of said block and adapted to be connected to an electrical receptacle,
a ground plate positioned within said rigid block and comprising a conductive plate with a plurality of holes formed therein through which said pins project in spaced and insulated relation to said conductive plate,
a plurality of ground connectors with the ends of the other of each of said pairs of wires connected to different ones of said ground connectors, said ground connectors being formed of a conductive material and being connected to said ground plate,
and at least one ground pin parallel to said plurality of pins secured in said insulating block with one end connected to said ground plate and the other adapted to be connected to said electrical receptacle.
2. A device as set forth in claim 1 wherein said plurality of pins are elongated and flat, and
said ground connectors are tubular with said ground connectors arranged intermediate and parallel said plurality of pins.
3. A device as set forth in claim 2 wherein insulating sleeves cover the connections of the ones of said pairs of wires to said pins.
4. In combination with a cable for high frequency electrical signal transmission having a plurality of pairs of conductors with each pair including a signal conductor and a grounded conductor in physically adjacent relation to one another along at least a portion of their length,
means for electrically connecting each of said signal conductors to an electrical receptacle including a plurality of pins with the ends of each of said signal conductors connected to different ones of said pins,
means for grounding said grounded conductors including a conductive ground plate adjacent and insulated from said pins with means connecting said ground plate with the ends of said grounded conductors, and means adapted to electrically connect said ground plate to a ground connection.
5. In combination with a cable for high frequency electrical signal transmission having a plurality of pairs of intertwined insulated wires having adjacent ends, a terminal comprising,
means for electrically connecting one each of said pairs of wires at said ends to an electrical receptacle including a plurality of pins with .said ends of one of each of said pairs of wires connected to different ones of said pins,
means for grounding the other of said pairs of wires including a conductive ground plate having a plurality of holes therein through which said pins project whereby said plate extends laterally of and intermediate the ends of said pins,
means connecting said ground plate with said ends of the other of each of said pairs of wires,
and means adapted to electrically connect said ground plate to a ground.
6. A device as set forth in claim 5 wherein said means connecting said ground plate with said other wires includes a plurality of ground conectors extending from one side thereof and intermediate said pins with said ground connectors each connected to one of said other of each of said pairs of wires.
7. A terminal for a multiwire cable for high frequency electrical signal transmission wherein said cable has a plurality of twisted pairs of wires including,
a plurality of pins with corresponding ends connected one each to one of each of said pairs of wires and with the other corresponding ends of said pins adapted to be connected to an electrical receptacle,
a ground plate for-med with a plurality of holes and positioned in insulated relation and intermediate the ends of said pins with said plate connected electrically to the others of said pairs of wires, and
means for grounding said plate whereby cross talk signals induced by said one wires -will be picked up and grounded by said other wires.
References Cited by the Examiner UNITED STATES PATENTS 2,006,436 7/1935 Bowers 339l8 2,390,706 12/1945 Hearon 339-18 X 2,923,860 2/1960 Miller 3l7101 3,179,913 4/1965 Mittler et al. 33918 JOSEPH D. SEERS, Primary Examiner.
PATRICK A. CLIFFORD, Assistant Examiner.