|Publication number||US3582536 A|
|Publication date||Jun 1, 1971|
|Filing date||Apr 28, 1969|
|Priority date||Apr 28, 1969|
|Publication number||US 3582536 A, US 3582536A, US-A-3582536, US3582536 A, US3582536A|
|Inventors||Miller Robert F|
|Original Assignee||Andrew Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (32), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Inventor RobertRMiller 3,870,792 1/1959 Penrose l74/l02(.6)X Chicago,lll. 3.121.136 2/1964 Mildnernm 174/28 AppLNo. 819,691 3,173,990 3 1965 Lamons l74/I02(.6)
Filed Apr. 28, 1969 FOREIGN PATENTS :ff f: 3 794,933 /1958 0166113111616 174/102.6
939,399 11 1948 France 174/28 Orland Park, Ill.
, Primary Examiner-Lararnie E. Askin AssislantExaminerA. T. Grimley CORRUGATED COAXIAL CABLE 1 Attorney-Leonard G. Nierman 2 Claims, 2 Drawing Figs.
 US. Cl 174/102, 138/121  Int.Cl ..H0lb11/18 Field of Search 174/102,
102.6, 106.6, 36, 28, 29; 138/121, 2 128, 114, ABSTRACT: The bending life ofcoaxial cable with a helically 173; 333/96 99 corrugated copper outer conductor is greatly increased, without impairment of other important mechanical or electri-  References cued cal characteristics, by employing specific relations of corruga- UNITED STATES PATENTS tion pitch and depth to each other and to overall cable diame- 2,8l7,363 12/1957 Penrose 174/102(.6)X ter.
0. P d 0. F 20 0.05P 7' 0.20P
PATENIED JUN 1 ml JNVEWTOR OBERT F. MILLER 1 CORRUGATED COAXIAL CABLE superior resistance to crushing or other cross-sectional deformation, together with exclusion of moisture and similar mechanical advantages which permit operation under conditions which would produce prohibitive degradation of the performance of older cables, the corrugated sheath of outer conductor of solid copper provides substantially lower attenuation and, at thesame time, complete containment of leakage radiation. Wherever high standards of cable performance are required, particularly where conditions of use produce a hazard of crushing, etc., the corrugated cable is normally advantageous. However, a notable exception has heretofore existed in the type of use wherein the cable is exposed to frequent flexing. ln permanent fixed cable installations, the corrugated cable is more or less freely interchangeable with older types of cable, the flexibility being generally fully adequate even though substantially less than that of the braided cable. However, the corrugated cable known before the present invention has not been suitable for applications involving repeated bending, as in coupling items of equipment frequently moved with respect to each other or in a movable test equipment and similar uses wherein the required bending force and the limited bending life which are of little significance in fixed installations become important.
A typical corrugated foam cable is half-inch 50-ohm cable with a dielectric of low-loss polyethylene foam. Such cable has been manufactured for a number of years and is often used in fixed runs where braided cable would have been previously used. Such'cable, however, had heretofore had very limited bending life. The outer conductor of such cable normally fails after about a hundred or so cycles of bending back and forth to a radius of the neighborhood of 5 inches on a mandrel. Such mandrel bending'is of course not fully representative of actual conditions of use, in which the end of the cable is normally affixed to some item of equipment, and the bending motion is some form of back-and-forth movement of a remote portion of the cable, thus producing nonuniform bending which is maximized at the point where the cable is secured, i.e., its point of connection to an end connector. (The point of stress need not, of course, be at the end of the cable, since passage through a panel-mounted or wall-mounted feed-through bushing will have the same effect). Accordingly, the bending life may be specified in terms of a test more closely approximating actual use conditions than cycles of "radius bends." One simple form of test rocks" the free end of a test specimen back and forth to apply reverse bending about a rigidly clamped portion until the point of failure. Such a test is readily automated by reciprocatory motion of a support ring or fork about a central position aligned with the clamped portion of the cable. A back-and-forth stroke of about inches (5 inches in each direction from the neutral position) at about 9 inches from the point of clamping of the cable produces failure points (in terms of full-bending cycles) fairly accurately predicting cable performance under most conditions of use for a halfinch cable. The corrugated cables of the prior art are found to fail after a number of cycles of the same general magnitude as in the reverse mandrel bending, i.e., ofthe order of l00 to 150 cycles.
lt has been found that a large improvement can be effected in the bending life ofcorrugated copper foam-dielectric cables previously known by proper relation of the pitch of the helical corrugations to their depth and to the overall cable diameter. Not only is this improvement accompanied by no important loss or diminution of other features of mechanical or electrical performance, but indeed the performance features are substantially improved in a number of respects beyond the increase in bending life. Resistance to hydrostatic pressure is increased by a substantial factor and there is also increase of the strength against impact. The cable is much more flexible in terms of the force required for bending and the minimum bending radius is substantially reduced.
The manner of achievement of these objects is best described in connection with the drawing, in which:
FIG. 1 is a view, partially in side elevation and partially broken away in longitudinal section, of the foamdielectric cable of the invention; and
FIG. 2 is a transverse sectional view of the cable.
Except for the dimensioning established by experimentation, the illustrated cable is of conventional construction. The inner conductor 12, of stranded wire, is surrounded by a foamdielectric sleeve 14 extruded thereon and the outer conductor 16, formed from a strip and welded at 18, is helically corrugated, the root or inner diameter 20 of the corrugation compressing the foam dielectric, but the crest 22 being spaced from the dielectric. If so desired, the void 24 thus formed may be provided with moisture barriers (not illustrated) as described in US. Pat. No. 3,394,400 of Robert P. Lamons. The cable illustrated also employs, when so desired, a suitable plastic jacket. Where such a jacket is applied by extrusion, however, care must be used to insure that the plastic does not extend to any substantial depth in the corrugations.
The primary object alteration of prior art constructions required for achievement of the improved performance of the invention is, shown by legend in the drawing, employment ofa corrugation depth d and pitch P such that the ratio of the former to the latter is between 0.55 and 0.70. The outer diameter D,, is from 3.5 to 4.5 times the pitch, and the thickness T of the copper sheet forming the outer conductor is between 0.05 P and 0.20 P.
An exemplary embodiment of the invention employs an inner conductor 12 of No. 8(AWG) seven-strand copper wire, of which is extruded a foam polyethylene dielectric of approximately 0.325 outer diameter. The outer conductor 16 is formed from copper strip of0.0l0-inch thickness and helically corrugated, with generally sinusoidal corrugation configuration, to a depth of approximately 0.075 inch with a helix pitch of approximately 0.120. The bending life of the half-inch outer diameter cable is a large multiple of that of a conventional corrugated half-inch cable. The simulated actual usetest oscillation earlier described produced an average bending life of well over 1500 cycles. The reverse bending on a 5-inch radius produced no failures within the lifetime thus indicated by the other test.
What I claim is:
1. ln a coaxial cable comprising an inner conductor, a foam dielectric surrounding the inner conductor, and a helically corrugated copper outer conductor surrounding the dielectric, the improved construction having the ratio of the corrugation depth to the corrugation pitch of the copper outer conductor substantially in the range of 0.55 to 0.70 with the copper outer conductor having a ratio of thickness to corrugation pitch between 0.05 and 0.20 and having a ratio of outer diameter to pitch at least equal to 3.5, and having an inner conductor of stranded wire.
2. The coaxial cable of claim 1 having the ratio of the outer diameter to corrugation pitch between 3.5 and 4.5.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2817363 *||Oct 30, 1953||Dec 24, 1957||Pirelli General Cable Works||Corrugated aluminium tube and electric cable employing the same as a sheath|
|US3121136 *||Jun 30, 1961||Feb 11, 1964||Charles Mildner Raymond||Co-axial cable having inner and outer conductors corrugated helically in opposite directions|
|US3173990 *||Aug 27, 1962||Mar 16, 1965||Andrew Corp||Foam-dielectric coaxial cable with temperature-independent relative conductor length|
|US3870792 *||Aug 10, 1973||Mar 11, 1975||Michiro Inoue||Certain dihydrophthalizines for treating hemorrhage and thrombosis|
|FR939399A *||Title not available|
|GB794933A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3745232 *||Jun 22, 1972||Jul 10, 1973||Andrew Corp||Coaxial cable resistant to high-pressure gas flow|
|US3797104 *||Jul 13, 1972||Mar 19, 1974||Pote W||Flexible coaxial cable and method of making same|
|US4368350 *||May 28, 1981||Jan 11, 1983||Andrew Corporation||Corrugated coaxial cable|
|US4631392 *||Jul 13, 1984||Dec 23, 1986||Raychem Corporation||Flexible high temperature heater|
|US4749823 *||Apr 6, 1987||Jun 7, 1988||Kabelmetal Electro Gesellschaft Mit Beschrankter Haftung||Multi-wire electric power cable, particularly a supply cable for borehole units|
|US4758685 *||Nov 24, 1986||Jul 19, 1988||Flexco Microwave, Inc.||Flexible coaxial cable and method of making same|
|US4822955 *||Mar 2, 1988||Apr 18, 1989||Siemens Aktiengesellschaft||Cable with a core surrounded by a band having tensile elements|
|US4921147 *||Feb 6, 1989||May 1, 1990||Michel Poirier||Pouring spout|
|US5239134 *||Jul 17, 1992||Aug 24, 1993||Flexco Microwave, Inc.||Method of making a flexible coaxial cable and resultant cable|
|US5527995 *||Aug 3, 1994||Jun 18, 1996||The Okonite Company||Cable for conducting energy|
|US5687774 *||Dec 29, 1995||Nov 18, 1997||Chiang; Hanh||Flexible lamp tube for connecting a lamp and a lamp base|
|US5760334 *||Jul 24, 1996||Jun 2, 1998||Alcatel Kabel Ag & Co.||Metallic sheath for an electric cable and method of making the same|
|US6255591 *||Dec 3, 1999||Jul 3, 2001||Gerhard Ziemek||Electric cables with metallic protective sheaths|
|US6624358 *||Dec 13, 2001||Sep 23, 2003||Andrew Corporation||Miniature RF coaxial cable with corrugated outer conductor|
|US6693241||Apr 24, 2002||Feb 17, 2004||Andrew Corporation||Low-cost, high performance, moisture-blocking, coaxial cable and manufacturing method|
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|US7044785||Jan 16, 2004||May 16, 2006||Andrew Corporation||Connector and coaxial cable with outer conductor cylindrical section axial compression connection|
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|US8646490 *||Jul 27, 2010||Feb 11, 2014||Nexans||Pipeline and method for producing the same|
|US8779293 *||Oct 7, 2009||Jul 15, 2014||Ls Cable & System Ltd.||Coaxial cable|
|US9171659 *||Sep 14, 2012||Oct 27, 2015||Abb Research Ltd||Radial water barrier and a dynamic high voltage submarine cable for deep water applications|
|US20030016532 *||Jun 12, 2002||Jan 23, 2003||David Reed||Method and apparatus for flexible led lamp|
|US20030201116 *||Nov 14, 2002||Oct 30, 2003||Andrew Corporation||Low-cost, high performance, moisture-blocking, coaxial cable and manufacturing method|
|US20050159043 *||Jan 16, 2004||Jul 21, 2005||Andrew Corporation||Connector and Coaxial Cable with Outer Conductor Cylindrical Section Axial Compression Connection|
|US20050159044 *||Nov 8, 2004||Jul 21, 2005||Andrew Corporation||Connector and Coaxial Cable with Outer Conductor Cylindrical Section Axial Compression Connection|
|US20060066421 *||Nov 26, 2003||Mar 30, 2006||Dominique Lo Hine Tong||Bandpass filter with pseudo-elliptic response|
|US20100212926 *||Aug 26, 2010||Bong-Kwon Cho||Coaxial cable|
|US20110036440 *||Feb 17, 2011||Christian Frohne||Pipeline and mehtod for producing the same|
|US20150107873 *||Apr 16, 2014||Apr 23, 2015||Dekoron Wire & Cable LLC||Flexible armored cable|
|USRE30194 *||Oct 11, 1977||Jan 15, 1980||Bunker Ramo Corporation||High frequency coaxial cable|
|CN101000812B||Dec 8, 2006||Dec 8, 2010||江苏亨鑫科技有限公司||Corrogated pipe outer conductor leakage radio-frequency coaxial cable for mobile communication|
|U.S. Classification||174/102.00D, 138/121|
|Cooperative Classification||H01B11/1839, H01B11/1808|
|European Classification||H01B11/18D2, H01B11/18B|