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Publication numberUS3582536 A
Publication typeGrant
Publication dateJun 1, 1971
Filing dateApr 28, 1969
Priority dateApr 28, 1969
Publication numberUS 3582536 A, US 3582536A, US-A-3582536, US3582536 A, US3582536A
InventorsMiller Robert F
Original AssigneeAndrew Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Corrugated coaxial cable
US 3582536 A
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Description  (OCR text may contain errors)

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.

[52] US. Cl 174/102, 138/121 [51] 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- [56] 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.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2817363 *Oct 30, 1953Dec 24, 1957Pirelli General Cable WorksCorrugated aluminium tube and electric cable employing the same as a sheath
US3121136 *Jun 30, 1961Feb 11, 1964Charles Mildner RaymondCo-axial cable having inner and outer conductors corrugated helically in opposite directions
US3173990 *Aug 27, 1962Mar 16, 1965Andrew CorpFoam-dielectric coaxial cable with temperature-independent relative conductor length
US3870792 *Aug 10, 1973Mar 11, 1975Michiro InoueCertain dihydrophthalizines for treating hemorrhage and thrombosis
FR939399A * Title not available
GB794933A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3745232 *Jun 22, 1972Jul 10, 1973Andrew CorpCoaxial cable resistant to high-pressure gas flow
US3797104 *Jul 13, 1972Mar 19, 1974Pote WFlexible coaxial cable and method of making same
US4368350 *May 28, 1981Jan 11, 1983Andrew CorporationFoamed fluorinated ethylene-propylene polymer dielectric between two conductors
US4631392 *Jul 13, 1984Dec 23, 1986Raychem CorporationElongated heating element within flexible corrugated metal tube
US4749823 *Apr 6, 1987Jun 7, 1988Kabelmetal Electro Gesellschaft Mit Beschrankter HaftungMulti-wire electric power cable, particularly a supply cable for borehole units
US4758685 *Nov 24, 1986Jul 19, 1988Flexco Microwave, Inc.Flexible coaxial cable and method of making same
US4822955 *Mar 2, 1988Apr 18, 1989Siemens AktiengesellschaftCable with a core surrounded by a band having tensile elements
US4921147 *Feb 6, 1989May 1, 1990Michel PoirierPouring spout
US5239134 *Jul 17, 1992Aug 24, 1993Flexco Microwave, Inc.Method of making a flexible coaxial cable and resultant cable
US5527995 *Aug 3, 1994Jun 18, 1996The Okonite CompanyCable for conducting energy
US5687774 *Dec 29, 1995Nov 18, 1997Chiang; HanhFlexible lamp tube for connecting a lamp and a lamp base
US5760334 *Jul 24, 1996Jun 2, 1998Alcatel Kabel Ag & Co.Metallic sheath for an electric cable and method of making the same
US6255591 *Dec 3, 1999Jul 3, 2001Gerhard ZiemekElectric cables with metallic protective sheaths
US6624358 *Dec 13, 2001Sep 23, 2003Andrew CorporationMiniature RF coaxial cable with corrugated outer conductor
US6693241Apr 24, 2002Feb 17, 2004Andrew CorporationLow-cost, high performance, moisture-blocking, coaxial cable and manufacturing method
US6808289Jun 12, 2002Oct 26, 2004RPM Optoelectronics, LLCMethod and apparatus for flexible led lamp
US6912777Nov 14, 2002Jul 5, 2005Andrew CorporationMethod of manufacturing a high-performance, water blocking coaxial cable
US7044785Jan 16, 2004May 16, 2006Andrew CorporationConnector and coaxial cable with outer conductor cylindrical section axial compression connection
US7391287 *Nov 26, 2003Jun 24, 2008Thomson LicensingBandpass filter with pseudo-elliptic response
US8646490 *Jul 27, 2010Feb 11, 2014NexansPipeline and method for producing the same
US20110036440 *Jul 27, 2010Feb 17, 2011Christian FrohnePipeline and mehtod for producing the same
USRE30194 *Oct 11, 1977Jan 15, 1980Bunker Ramo CorporationHigh frequency coaxial cable
CN101000812BDec 8, 2006Dec 8, 2010江苏亨鑫科技有限公司Corrogated pipe outer conductor leakage radio-frequency coaxial cable for mobile communication
Classifications
U.S. Classification174/102.00D, 138/121
International ClassificationH01B11/18
Cooperative ClassificationH01B11/1839, H01B11/1808
European ClassificationH01B11/18D2, H01B11/18B