|Publication number||US3804972 A|
|Publication date||Apr 16, 1974|
|Filing date||Jan 29, 1973|
|Priority date||Feb 8, 1972|
|Also published as||CA987754A1, DE2303792A1, DE2303792B2, DE2303792C3|
|Publication number||US 3804972 A, US 3804972A, US-A-3804972, US3804972 A, US3804972A|
|Inventors||Gommans H, Stikkelbroeck J|
|Original Assignee||Philips Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (6), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Gommans et al.
[ Apr. 16, 1974 ELECTRICAL CONNECTION OF COAXIAL CABLE ENDS Inventors: Hubertus Johannes Josephus Gommans; Josephus Gerardus Henricus Stikkelbroeck, both of Venlo, Netherlands U.S. Philips Corporation, New
Filed: Jan. 29, 1973 Appl. No.: 327,491
Foreign Application Priority Data  References Cited UNITED STATES PATENTS 3,151,211 9/1964 Reid et a1. 174/92 X 288,311 11/1883 Cobb 174/92 2,657,252 10/1953 Mildner et al. 174/88 C 2,937,228 5/1960 Robinson 174/88 C 3,001,003 9/1961 Robinson 174/88 C Primary Examiner-Darrell L. Clay Attorney, Agent, or Firm-Frank P. Trifari  ABSTRACT A connection for coaxial cable ends in which a con- Feb. 8, 1972 Netherlands 01606 nection is obtained between the respective cable dielectrics with the aid of connection pieces of electri- U.S. Cl 174/88 C, 174/92, 339/103 R, cally insulating material engaging slots in the dielec- 339/176 R tric. Int. Cl l-l02g 15/08 Field of Search 174/88 c, 92, 93, 75 c, 4 Claims 8 W 174/89; 315. 117? R, 177R, 71 1 103 M PATENTEMPR 16 m4 3804-372 SHEET 1 OF E ELECTRICAL CONNECTION F COAXIAL CABL ENDS The invention relates to an electrical connection of two coaxial cable ends each consisting of a central conductor, a solid dielectric surrounding the central conductor, a cylindrical outer conductor and a sheath, the central conductors and the outer conductors being electrically connected respectively together in a conventional manner, for example, by means of clamping connections. The invention further relates to a method of manufacturing such a connection. As a result of the increasing use of communal aerial systems particularly also for television reception there is a great need of reliable connections between coaxial cable ends of equal or unequal diameters with respect to each other.
The most important requirement imposed on such connections is that reflections which deteriate the signal distributed through the cable must not be produced. In addition the connection must be water resistant and it must be able to withstand pulling forces occuring during normal handling of the cable.
The existing connections are in general of a complicated nature and are expensive and easily give rise to errorsQThey can only be applied by specially trained people.
In some known connections the electrical connection between the central conductors is stressed where the cable is subjected to pulling forces. This may give rise to unwanted alterations in the electrical behaviour of the cable. In other connections the sheath is stressed under such circumstances and may be damaged so that moisture can penetrate the cable.
An object of the invention is to provide a connection which can be applied without errors and with as few tools as possible by untrained personnel after some instructions, which connections may be subjected to pulling forces without unwanted alterations occurring in the electrical behaviour of the cable.
According to the invention a connection between two coaxial cable ends which satisfied this condition is characterized in that the cable ends are mechanically connected together by means of connection pieces of electrically insulating material provided with parts projecting in the direction of the central conductor, said parts being accommodated in recesses in the solid dielectrics of the respective cable ends.
A preferred embodiment of the connection according to the invention is characterized in that the connection pieces consist of shells of electrically insulating material which are provided on their inner side with at least two radially varying elevations engaging radially varying slots in the cable dielectric of the two cable ends. From an electrical point of view it is necessary that the impedance at the area of the connection is equal to that of the cables connected'together. Thus, before the shells are provided such a quantity of that part of the dielectric located between the radial slot and the cable end is radially removed that after the shells are applied the outer diameter of the shells coincides with the original outer diameter of the dielectric which was located at the area of the connection. The thickness of the part removed from the cable is then equal or substantially equal to the thickness of the shells. It is achieved thereby that the diameter of the cable dielectric between the radial slots and the cable end plus the thickness of the shell at that area is equal or substantially equal to the original diameter of the cable dielectric in that area.
In order to realize a satisfactory electrical connection between the central conductors, the central conductors are exposed over a given distance and these exposed ends are slid in a metal bush provided with an envelope of insulating material. The metal bush may be provided with one or more axial slots and may have a slightly smaller inner diameter than the diameter of the central conductor so that a clamping connection is obtained. The outer diameter of the insulating envelope of this cylindrical connection piece is preferably equal to the diameter of the adjacent parts of the cable dielectric. If these diameters differ, the diameter at each end is equal to the diameter of the adjacent cable dielectric. The diameter between the two ends then varies, for ex.- ample, regularly with the distance so that a conical shape is obtained while it is of course to be ensured that the impedance at that area is equal to that of the cable ends. This envelope may be connected to one of the shells. An electrical connection between the cylindrical outer conductors may be obtained, for example, with the aid of shells of metal overlapping parts of the outer conductor and being provided in a clamping manner on the outer conductors with the aid of a clamping device, for example, clamping rings. These shells are preferably provided with adjoining profiled edges at least in the area of the connection so as to avoid outward radiation. Subsequently an outer sheath may be provided, for example, by applying a heat shrinkable plastics tube or a self-vulcanizing sealing tape to the assembly.
A preferred embodiment of the invention and a method of manufacturing such a connection will not be described in greater detail with reference to the accompanying drawing.
FIGS. 11 to 3 show axial cross-sections of cable ends at various preparatory stages for the provision of the connection according to the invention,
FIG. 4 shows a connection according to the invention in an axial cross-section.
FIG. 5 shows the cylindrical connection piece in a radial cross-section.
FIG. 6 shows a shell-shaped connection piece axial cross-section.
FIG. 7 shows two shell-shaped connection pieces in a radial elevation view.
FIG. 8 shows a finished connection in an axial crosssection.
FIG. I shows one end of a coaxial cable in an axial cross-section. The cable comprises a central conductor 1 of solid copper, a solid dielectric 2 of polyethylene, an outer conductor 3 of copper foil and/or copper stranded wire and an outer sheath 4 of polyethylene. An equal part of the sheath 4 and the outer conductor 3 is removed from the cable end, while the outer sheath 4 is radially cut at 5 as far as the outer conductor 3. Subsequently part of the dielectric 2 is removed so that after this operation the central conductor partly projects beyond the dielectric (FIG. 2). Two shells (6 and 7) are removed from the dielectric. If desired, this operation may be combined with the previous operation, unbaring part of the central conductors. The slot obtained by removing the shell 6 serves to accommodate the'part 9 projecting on the inner side of the shell 8. The reduction in diameter of the dielectric by removing the shell 7 serves to accommodate the thicl ness of the shell 8 so that, as shown in FIG. 4, the outer in an diameter at the area of the connection coincides with that of the solid dielectric of the cable ends. Subsequently the sheath part 4A is removed. The parts of the central conductor 1 projecting outside the solid dielectric are slid into the connection piece which is shown in a radial cross-section in FIG. 5. The connection piece 10 consists of a metal bush 11 which may have a slightly smaller diameter than the central conductors and may be provided with one or more axially varying slots so as to obtain a clamping tit, and an envelope of insulating material 12. Since the provision of the metal bush 11 causes the conductor diameter at the area of this connection to increase relatively, it is generally necessary to adapt, or in this case to decrease the dielectric constant of the material for the sheath 12 if this is the same material as that used for the solid dielectric 2. This may be realized, for example, by pro-- viding a plurality of ducts 13 (see FIG. 5) in the envelope 12parallel to the axis.
Subsequently the shells 8 are provided while the projecting edges 9 engage the recesses obtained by removing the shell 6. FIG. 6 is a longitudinal cross-section of such a shell 8. The shell 8 may be manufactured from the same electrically insulating material as that for the solid dielectric 2, for example, polyethylene. Two shells combined may constitute a closed cylinder sheath and it is alternatively possible to form the shells in such a manner that three or more shells constitute a closed cylinder sheath. Generally it is, however, preferred to limit the number of shells so that also the number of seams through which moisture might penetrate the cable is limited. FIG. 7 is a radial elevational view of two shells 8. In order to obtain a satisfactory sealing from moisture the tangent planes 14 may be provided with fitting ridges and slots. As a further step to prevent moisture penetration a thin coating of water repellent mass, for example, polyethylene wax or silicon grease may be provided between all parts. Subsequently two copper shells 15 and 16 are provided on the connection in an overlapping electrical contact with the outer conductors 3 and secured with the aid of clamping rings 18. Subsequently a tube of elastic electrically insulating material 17, for example, a shrink tube of polyethylene previously provided on one of the cable ends is slid over the assembly. This tube 17 serves as the outer sheath. In order to obtain a satisfactory sealing from moisture penetration it is preferred to have part of this tube 17 overlap the sheath 4 as it is shown in the Figure.
A connection as the one shown may be subjected to pulling forces normally occuring during handling of the cable without the risk of varying the electrical properties of the connection between the cable ends or the impedance at that area. Such a connection withstands without any risk realing and derealing on reels. The provision of cable muffs is generally not necessary because a sufficient water-tightness is obtained with the construction according to the invention.
A connection according to the invention may be used, for example, for connecting cable ends having a total diameter of 15 mms. or more.
What is claimed is:
1. Electrical connection of two coaxial cable ends each having a central conductor, a solid dielectric surrounding the central conductor, a cylindrical outer conductor and a sheath, the central conductors and the outer conductors being electrically connected together, connection pieces of electrically insulating material mechanically connecting the ends of said cables together, said connection pieces being provided with parts projecting in the direction of the central conductor, said parts engaging recesses in the solid dielectrics of the respective cable ends.
2. Electrical connection of two co-axial cable ends as claimed in claim 1, wherein said connection pieces comprise shells of electrically insulating material being provided with at least two radially extending elevations engaging radially extending slots in the dielectric of the two cable ends.
3. An electrical connection of two coaxial cable ends as claimed in claim 2, wherein the diameter of the cable dielectric between the radially extending slots plus the thickness of the shells at that area is substantially equal to the original diameter of the cable dielectric at that area.
4. An electrical connection of two coaxial cable ends as claimed in claim 3, wherein the central conductors project outside the cable dielectric of the cable ends, and further comprising a metal bush slid over the two ends of the central conductors electrically connecting said conductors together and an envelope of electrically insulating material enveloping said bush, the diameter of the envelope at each end being substantially equal to that of the adjacent cable dielectric parts.
m I UNITED STATESIPATENVT OFFICE CERTIFICATE OF CORRECTION Patent No; 38049723 Datedv April l6, 1974 Inventor-( HUBERTUS JOHANNES JOSEPHUS GOMMANS ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
In the heading:
under " Foreign ApplicatiorrPriority Data" 01606 should be -720l606 Signed "and sealed this 24th day of September 1974,
(SEAL) Attest: v
McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents @3 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No; 3804972- v I Dated I April 1.6, 1974 Inventor(s) HUYBERTUS JOHANNES JOSEPHUS GOMMANS ET AL It is certified that error apfiears in the above-identified patent and that said Let ters Patent; are hefeby corrected as shown below:
In the heading:
under ": Foreign Applicatioh Priority Data" "01606" should be --720l606 Signed and sealed this 24th day of September 1974,
C. MARSHALL DANN Commissioner of Patents MCCOY M. GIBSON JR. Attesting Officer
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US288311 *||Jun 1, 1883||Nov 13, 1883||Subteeeanean line of electeic wiees|
|US2657252 *||Feb 27, 1950||Oct 27, 1953||Telegraph Constr & Maintenance||Joint for coaxial electrical cables|
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4594474 *||Feb 4, 1985||Jun 10, 1986||Georg Spinner||Connecting device for coaxial cables|
|US4653840 *||Jun 20, 1986||Mar 31, 1987||Amp Incorporated||Electrical connections for shielded coaxial conductors|
|US4698458 *||Sep 26, 1985||Oct 6, 1987||Societa' Cavi Pirelli S.P.A.||Joint for cables with an extruded insulation|
|US5888095 *||Dec 29, 1995||Mar 30, 1999||Rally Manufacturing, Inc.||Coaxial cable connector|
|US6322390 *||Oct 18, 2000||Nov 27, 2001||Cosmo Industry Co., Ltd.||Coaxial connector|
|US20150096803 *||Oct 7, 2013||Apr 9, 2015||Tyco Electronics Uk Ltd.||Cable Repair Splice|
|U.S. Classification||174/88.00C, 439/578, 439/449, 174/92|