(12) United States Patent
`Holland et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 8,376,769 B2
`Feb. 19, 2013
`
`US008376769B2
`
`8/1992 Verespejetal.
`5,137,471 A
`5683263 A * 11/1997 H311 ............................. .1439/319
`6,217,383 B1
`4/2001 Hollandet al.
`6,712,631 B1
`3/2004 Youtsey
`6,716,062 B1
`4/2004 Palinkas et a1.
`7,131,867 B1
`11/2006 Foster et al.
`7,479,035 B2
`1/2009 Bence et al.
`
`9/2009 01136112 ......................... ~ 607/37
`7,587,244 132*
`7,674,132 B1*
`3/2010 Chen ..... ..
`439/578
`7/2010 Montena ..................... .. 439/277
`7,753,705 B2*
`7,828,595 B2
`11/2010 M th
`7,392,024 131 =1
`2/2011 Cfenems, ,,,,,,,,,,,,,,,,,,,,,, H 439/573
`8,062,044 B2 *
`11/2011 Montena et al.
`439/277
`8,062,063 132*
`11/2011 Malloy etal.
`.... ..
`439/578
`8,157,589 B2*
`4/2012 Krenceskiet al.
`.
`439/578
`8,167,636 B1*
`5/2012 Montena ...... ..
`439/322
`8,172,612 132*
`5/2012 Bence etal.
`439/578
`8,192,237 B2*
`6/2012 Pu d
`t
`1.
`................. .. 439/792
`2010/0255721 A1
`10/2010 1>u§c1§ :1 :1.
`2012/0225581 A1*
`9/2012 Amidon et al.
`.
`.
`* cited by examiner
`
`
`
`............. .. 439/584
`
`Primary Examiner — Neil ‘Abrams
`(74) Attorney, Agent, or Fzrm — Paul D. Chancellor; Ocean
`Law
`
`(57)
`ABSTRACT
`A male F-Type coaxial cable connector has an improved RF
`shield including a bridge located between and electrically
`interconnecting a connector fastening nut and a connector
`body P0111011
`
`7 Claims, 7 Drawing Sheets
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`(54) COAXIAL CONNECTORWITH ENHANCED
`SHIELDING
`
`(75)
`
`Inventors: Michael llolland, S.anta.Barbara, CA
`(US); Ka1-Ch1hWe1, T811361 (TW)
`
`(73) Assignee: Holland Electronics, LLC,Ventura, CA
`(US)
`.
`.
`.
`.
`SubJeCt.t0 any dlsclalmers. the term Ofthls
`patent Is extended or adjusted under 35
`U.S.C. 154(b) by 272 days.
`
`.
`NOUCB3
`
`( * )
`
`.
`(21) APPLNO" 12/949334
`.
`(22)
`Flledi
`NOV-1312010
`
`(65)
`
`Prior Publication Data
`
`US 2012/0129387 A1
`
`May 24, 2012
`
`(51)
`
`Int CL
`(2006.01)
`H011; 9/05
`(52) U.s. Cl.
`..................................................... .. 439/322
`(58) Field of Classification Search ................ .. 439/320,
`439/321, 322, 578
`See application file for Complete Search history’
`References Cited
`
`(56)
`
`U.s. PATENT DOCUMENTS
`3,336,563 A *
`8/1967 Hyslop ....................... .. 439/603
`4,525,017 A
`6/1985 Schildkraut et al.
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`Feb. 19, 2013
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`Sheet 1 017
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`US 8,376,769 B2
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`
`
`Figure 1A,
`PRIOR ART
`
`
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`Figure 1B,
`PRIOR ART
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`U.S. Patent
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`Feb. 19, 2013
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`U.S. Patent
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`Feb. 19, 2013
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`PRIOR ART
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`Feb. 19, 2013
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`PRIOR ART
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`Feb. 19, 2013
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`US 8,376,769 B2
`
`1
`COAXIAL CONNECTOR WITH ENHANCED
`SHIELDING
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to an article of manufacture
`for conducting electrical signals. In particular, a male F-Type
`coaxial cable connector includes a bridge enhancing the elec-
`tromagnetic shielding provided by the mated connector.
`2. Discussion of the RelatedArt
`
`With the increased use of intemet/data applications on
`Cable TV systems, it has been found that outside electrical
`noise and signal ingress into the CATV network interferes
`with the data signals and reduces the velocity or speed of
`signal propagation. Because shielding tends to reduce this
`undesirable interference, increasing the shielding of every
`component in the distribution system has become a goal of
`CATV system designs seeking improved data transmission
`performance.
`One source ofnoise ingress in cable distribution systems is
`the coaxial cables’ F-Type connector. Male F-Type connec-
`tors generally include a post, a flange located at one end ofthe
`post, a rotatable front attachment nut engaging the flange, and
`a connector body aflixed to the post adjacent to the nut.
`Typically, the signal shield of these connectors is degraded
`when the attachment nut is loose. Despite attachment nut
`tightening specifications, such as 30 inch-pounds torque for
`some connectors, intended to insure a high degree of conduc-
`tivity and radio frequency (“RF”) shielding, movement of the
`coaxial cable, variations in temperature, or poor initial instal-
`lation workmanship can cause the F-Type male nut to loosen,
`allowing RF ingress through the RF gap created.
`Initial attempts to solve the F-Type connector shielding
`problem have been aimed at maintaining a tight front nut.
`This approach uses a split or locking washer 50 as shown in
`prior art FIG. 1A disclosed in U.S. Pat. No. 6,712,631 to
`Youtsey. In this washer behind the flange design, tightening
`the nut 30 on a mating part 62 compresses the locking washer
`between the flange 44 and the rear wall of the nut. This
`method has had some success in resisting vibrational loosen-
`ing, but it fails to prevent RF ingress if the nut is installed
`loose or later becomes loose.
`
`A second approach seeks to reduce RF ingress by provid-
`ing good ground continuity and RF shielding even when the
`front nut is loose. In a spring 16 behind the flange 26 design
`as shown in prior art FIG. 1B disclosed in U.S. Pat. No.
`6,716,062 to Palinkas et al., the second approach is imple-
`mentedusing a compressed spring that surrounds the post and
`operates to push the flange away from the rear wall of the nut
`which tends to press the male connector’s flange against the
`female connector’ s mating front face. By connecting the male
`and female connector ground planes, shielding is enhanced. It
`is a disadvantage that this design requires a larger and more
`costly male connector nut assembly to house the spring.
`Others implement the second approach using a spring 12 in
`front of the flange design as shown in prior art FIGS. 1C and
`1D disclosed in U.S. Pat. No. 7,753,705 to Montena. This
`spring is electrically and mechanically attached to the
`flange’s outer periphery or its inner bore which is part of the
`male connectors’ ground plane assembly. It is a disadvantage
`that this design operates over only a short compression dis-
`tance.
`
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`connector has a nonconductive outer body. Disadvantages of
`this design include a large contact spring and grounding to an
`inner, smaller diameter ground plane.
`
`SUMMARY OF THE INVENTION
`
`The present invention provides a coaxial cable connector
`with enhanced shielding. Various embodiments include one
`or more of the features described below.
`
`An electrically conductive member interconnecting the
`front attachment nut and the connector body assures DC
`continuity and RF shielding to an F-Type male coaxial cable
`connector when the front attachment nut is loose. Unlike
`
`traditional loose nut shielding methods, embodiments of the
`present
`invention locate an electrical contact member
`between the connectors’ attachment nut and a connector con-
`
`ductive body. Because RF currents travel mostly on a con-
`ductors’ outer surface, the use of the connector body as a
`conductor offers, in various embodiments, one or more of
`enhanced shielding, mechanical performance, and environ-
`mental performance as compared to traditional designs.
`Moreover, in various embodiments, the present invention
`requires no spring or similar shielding member to electrically
`interconnect the attachment nut and either of the post and
`flange of the connector ferrule tube.
`In an embodiment, an improved male F-Type connector
`radio frequency shield comprises an electrically conductive
`nut and a post substantially surrounded by an electrically
`conductive body. A nut partition separates a nut forward
`cavity and a nut rear cavity bounded at least in part by a nut
`overhang. The nut forward cavity encircles a flange at one end
`ofthe post and the nut rear cavity receives a forward mouth of
`the connector body. Also included is an electrically conduc-
`tive bridge having a frustoconical shape and a centerline
`about coincident with a central axis of the connector. The
`
`bridge is interposed between the forward mouth of the con-
`nector body and the nut overhang; and, the bridge mechani-
`cally contacts and thereby electrically interconnects the nut
`and the connector body.
`In some embodiments, the connector bridge is operable as
`a spring to press against a peripheral wall of the nut rear
`cavity. And, in some embodiments the bridge is in the form of
`a partial ring with a gap and the bridge operable as a spring to
`grip the forward mouth of the connector body. In various
`embodiments, the nut partition and/or the forward mouth of
`the connector body prevent the bridge from contacting the
`flange and the post.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The present invention is described with reference to the
`accompanying figures. These figures,
`incorporated herein
`and forming part of the specification, illustrate the invention
`and, together with the description, further serve to explain its
`principles enabling a person skilled in the relevant art to make
`and use the invention.
`
`FIGS. 1A-E show prior art coaxial cable connectors.
`FIG. 2 shows a side view in partial cross-section of a male
`F-Type type coaxial cable connector in accordance with the
`present invention.
`FIG. 3 shows an exploded view of selected parts of the
`coaxial cable connector of FIG. 2.
`
`A third approach has been to attach an electrically conduc-
`tive spring 110 between the loose nut and the flange as shown
`in prior art FIG. 1E disclosed in U.S. Pat. No. 7,479,035 to
`Bence et al. This type of design is especially useful where the
`
`65
`
`FIG. 4 shows a side view ofa bridge foruse with the coaxial
`cable connector of FIG. 2.
`
`FIG. 5 shows a plan view of a bridge for use with the
`coaxial cable connector of FIG. 2.
`
`

`
`US 8,376,769 B2
`
`3
`FIG. 6 shows a perspective View of a bridge for use with the
`coaxial cable connector of FIG. 2.
`
`DETAILED DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`The disclosure provided in the following pages describes
`examples of some embodiments of the invention. The
`designs, figures, and description are non-limiting examples of
`embodiments they disclose. For example, other embodiments
`ofthe disclosed device and/ormethodmay or may not include
`the features described herein. Moreover, disclosed advan-
`tages and benefits may apply to only certain embodiments of
`the invention and should not be used to limit the disclosed
`invention.
`
`FIG. 2 shows a male F-Type coaxial cable connector in
`accordance with the present invention 200. The connector
`includes a post 204, a flange or flange-like structure 219
`opposite a trailing end of the post 209, a rotatable front
`attachment nut surrounding the flange 202, and a connector
`body 206 affixed to the post adjacent to the nut. The nut end
`of the connector is referred to as the forward end 203 and the
`
`opposite end of the connector is referred to as the trailing end
`213. A nut forward cavity 215 is prepared, such as with
`threads 217, for mating with a female F-Type coaxial cable
`connector or port.
`In some embodiments, the present invention includes one
`or both of means for fixing a coaxial cable to the connector
`and means for moisture sealing the interior of the connector.
`An exemplary means for aflixing a prepared end of a coaxial
`cable to the connector 200 includes cooperation of a movable
`outer shell 208 with a deformable, trailing portion ofthe body
`207 (as shown).
`During deformation, a central region 21 1 ofthe deformable
`body portion moves radially inward toward the connector
`centerline X-X. This deformation squeezes the coaxial cable
`between the deformable body portion and barb(s) on the
`post’ s trailing end 205. Deformation occurs when the deform-
`able body portion’s free end 232 is pushed forward by an
`annular face 230 of the moving outer shell. As persons of
`ordinary skill in the art will appreciate, this embodiment
`describes one of many known cable/connector fixation
`designs that are suitable for use with the connector of the
`present invention.
`Exemplary moisture seals are shown in the embodiment of
`FIG. 2 where a first moisture seal such as an O-ring 214 is for
`sealing between the rotatable nut 202 and the post 204. Also
`shown is a second exemplary moisture seal such as another
`O-ring 216 for sealing between the body 206 and the outer
`shell 208. The use of these and other suitable moisture seals
`will be known to skilled artisans.
`
`In various embodiments ofthe present invention, enhanced
`shielding includes one orboth ofenhanced DC continuity and
`enhanced RF shielding of the male F-Type coaxial connector.
`Shielding is enhanced by providing a continuous or substan-
`tially uninterrupted ground plane surrounding the center con-
`ductor of the coaxial cable portion inserted in the connector.
`In particular, the rotatable connector nut 202 and the connec-
`tor body 206 are electrically conductive and electrically con-
`nected such that to the extent they surround the coaxial cable
`center conductor, they provide an effective RF shield around
`it.
`
`Notably, the electrically interconnected nut 202 and body
`206 ground plane provides a relatively low impedance RF
`path as compared to designs implementing an electrically
`interconnected nut and post 204 or flange 219 design. Lower
`impedance results because the RF signal travels primarily on
`
`4
`
`the surface of a conductor and the surface area (diameter) of
`the connector body is larger than the surface area (diameter)
`of the post.
`FIG. 2 shows an exemplary conductive bridge 210 provid-
`ing an electrical connection between the nut 202 and the body
`206. In some embodiments, one or more of a nut partition
`218, a nut overhang 220, a body forward mouth 224, and a
`forward body shoulder 222 are adjacent to the bridge. And, in
`some embodiments the bridge fits in a pocket 212. In an
`embodiment, the bridge fits in a pocket formed by the nut
`partition 218, the nut overhang 220, the body forward mouth
`224, and the forward body shoulder 222 (as shown).
`Suitable bridges are made from materials including resil-
`ient materials.
`In various embodiments bridge materials
`include one or both of metallic and non-metallic conductors.
`
`Exemplary bridge materials include: Metallic conductors
`such as stainless steel, steel, beryllium, copper, or an alloy of
`one or more of these metals; non-metallic conductors such as
`a conductive polymer; and, composite conductors such as a
`non-metallic matrix containing conductive material(s) such
`as finely divided conductive metal and carbon based materi-
`als.
`
`FIG. 3 shows an exploded diagram of a first portion of the
`connector 300. The conductive bridge 210 is shown and the
`interengaging attachment nut 202 and connector body 206 are
`shown. When assembled (see also FIG. 2), the bridge touches
`both the attachment nut 202 and the connector body 206
`establishing an electrical path therebetween. Notably, the nut
`is free to rotate with respect to the connector body as the
`bridge rubs against one or both of the nut and the body.
`In an embodiment, the bridge 210 has a frustoconical shape
`with a major lip 240 and a minor lip 242 (as shown). The
`bridge is designed to fit within the rear cavity of the nut 306
`such that the major lip of the bridge interengages an interior
`surface of a nut rear cavity 302. A second interengagement
`occurs where the bridge minor lip touches an outer surface
`304 of the connector body forward mouth 224.
`Whether the bridge 210 is in the form of a partial or a
`continuous ring, during interengagement the bridge touches
`the nut 202 and the connector body 206. In an embodiment,
`the bridge’s major lip describes an interengaging outer diam-
`eter d2 that is larger than the inner diameter of the nut rear
`cavity d1 forming a first interference fit. And, in an embodi-
`ment, the bridge’s minor lip describes an interengaging inner
`diameter d3 that is smaller than the outer diameter d4 of the
`
`body forward mouth forming a second interference fit. In
`various embodiments the bridge lips are continuous and cre-
`ate continuous lines of contact with the nut and the connector
`
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`body. And, in some embodiments, the bridge lips are discon-
`tinuous and create discontinuous lines of contact with the nut
`
`and the connector body.
`FIGS. 4-6 show exemplary plan, side, and perspective
`views illustrating bridge designs 400, 500, 600. In FIG. 4, a
`bridge side view shows a bridge sidewall 402 extending
`between major and minor lips ofthe bridge 240, 242. The side
`wall and a bridge centerline Y-Y describe a bridge angle 6.
`As can be seen, for a given sidewall length u, the width of
`the bridge v is a function of angle 6; increasing 6 reduces
`width while decreasing 6 increases width. In various embodi-
`ments, the bridge angle 6 varies in the range of about 15 to 50
`degrees and in some embodiments the bridge angle 6 varies in
`the range of about 30 to 40 degrees.
`As will be appreciated by persons of ordinary skill in the
`art, bridge dimensions d2, d3 are selected in light of nut and
`connector body dimensions d1, d4. Bridge thickness t is
`selected to maintain snug fits and good electrical contacts
`with the nut 202 and the connector body 206
`
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`65
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`

`
`US 8,376,769 B2
`
`5
`Suitable bridge thickness is a function of the bridge mate-
`rial properties and the bridge angle 0. For example, a stainless
`steel part might be made from a 304 stainless or similar
`material with Rockwell B hardness in the range of about
`90-94 and with a thickness in the range of about 0.3 to 0.6
`millimeters. In an embodiment, a bridge is made from 304
`stainless with a Rockwell B hardness of 92 and a thickness of
`0.4 mm.
`
`FIG. 5 shows a plan View of a partial ring bridge 500. Here,
`a variable gap g in the ring forming the bridge 210 enables the
`bridge to accommodate a range of connector body forward
`mouth outer diameters d4. In accordance with the mechanical
`
`properties ofthe bridge material, accommodating larger body
`mouths by increasing the gap also tightens the fit between the
`bridge and the connectorbody 206. In addition, increasing the
`gap increases the bridge outer diameter d2 which tightens the
`fit between the bridge and the nut 202.
`A feature of the partial ring bridge design is that energy
`associated with bridge deformation can be stored in corre-
`sponding gap changes. This provides an increased range of
`resilient bridge deformation as compared to bridges without a
`similar energy storing capacity such as a continuous ring
`bridge.
`Another feature of the partial ring bridge design is that
`energy associated with bridge deformation can be stored in
`corresponding changes in the angle 0. For example, tighten-
`ing the fit between the nut and the bridge tends to flatten the
`bridge as evidenced by a reduced angle 0.
`In operation, a conductive bridge 210 enhances the RF
`shield. In various embodiments, the bridge is located between
`the nut’s rear cavity 302 and a mouth of the connector body
`forward mouth 224. The conductive bridge contacts the nut
`and the connector body forward mouth providing an electrical
`path therebetween. Because ofthe fits between the bridge and
`each of the nut and the connector body forward mouth, the
`electrical interconnection is maintained whether the nut is
`
`loose or tight. For example, the electrical interconnection and
`the enhanced RF shield are maintained whether the nut is
`
`loose or tightly fastened to a mating female F-Type connector
`port.
`When the nut 202 is tightened onto a mating port, the
`bridge rubs against the nut and/or the connector body forward
`mouth. In some embodiments, this relative motion tends to
`clean mating electrical contact areas and enhance conductiv-
`ity between the nut and the connector body 206. And, in some
`embodiments tightening the nut also tends to reduce the
`bridge angle 0 and enhance conductivity between the nut and
`
`6
`the connector body, for example by one or more of relative
`motion rubbing/cleaning and increased bridge contact forces.
`While various embodiments of the present invention have
`been described above, it should be understood that they have
`been presented by way of example only, and not limitation. It
`will be apparent to those skilled in the art that various changes
`in the form and details can be made without departing from
`the spirit and scope of the invention. As such, the breadth and
`scope of the present invention should not be limited by the
`above-described exemplary embodiments, but should be
`defined only in accordance with the following claims and
`equivalents thereof.
`What is claimed is:
`
`1. An improved male F-Type connector radio frequency
`shield comprising:
`a post and an electrically conductive nut, the post substan-
`tially surrounded by an electrically conductive body;
`a nut partition separates a nut rear cavity and a nut forward
`cavity, the nut rear cavity bounded at least in part by a nut
`overhang;
`the nut forward cavity encircles a flange at one end of the
`post and the nut rear cavity receives a forward mouth of
`the connector body;
`an electrically conductive bridge having a frustoconical
`shape and a centerline about coincident with a central
`axis of the connector;
`the bridge interposed between the forward mouth of the
`connector body and the nut overhang; and,
`the bridge mechanically contacting and thereby electri-
`cally interconnecting the nut and the connector body.
`2. The connector of claim 1 wherein the bridge is operable
`as a spring to press against a peripheral wall of the nut rear
`cavity.
`3. The connector of claim 2 wherein the bridge is in the
`form of a partial ring with a gap and the bridge is operable as
`a spring to grip the forward mouth of the connector body.
`4. The connector of claim 3 wherein the nut partition and
`the forward mouth of the connector body prevent the bridge
`from contacting the flange and the post.
`5. The connector of claim 4 wherein the bridge has a “V”
`shaped cross-section.
`6. The connector of claim 5 where the bridge is made from
`a resilient material.
`
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`7. The connector of claim 6 wherein the bridge is made
`from stainless steel.