Coaxial cable connector sleeve

[0001] This disclosure relates generally to coaxial cable connectors and, more specifically, to a compliant sleeve adapted to assist in tightening the threaded nut of a connector to a port or fitting.

[0002] In using electronic devices such as cable boxes and cable modems, it is sometimes desired to connect such devices to televisions, digital video disc playback devices, digital video recorders, personal computers, or other sources of electronic signals. Typically, a coaxial cable supplied by a cable service company penetrates a wall in the user's premises and is distributed to one or more locations within the home through the use of additional coaxial cable segments typically referred to as jumper cables. The jumper cable is terminated near the location of the television, cable box, cable modem or digital phone. Each end of a jumper has a coaxial cable connector installed thereon. A common interface for the coaxial cable connector is an internally threaded rotatable nut. The connector threads onto an externally threaded port on the cable box, cable modem, or other device. Other devices may be connected to the cable box or cable modem using similarly configured coaxial cable jumpers and connectors.

[0003] Conventional coaxial cable typically contains a centrally located electrical conductor surrounded by and spaced inwardly from an outer cylindrical braided conductor or sheath. The center and braid conductors are separated by a foil and an insulator core, with the braid being encased within a protective outer jacket.

[0004] A first end of a conventional coaxial cable typically includes an inner cylindrical post adapted to be inserted into a suitably prepared end of the cable between the foil and the outer braid conductor, an end portion of the latter having been exposed and folded back over the protective jacket. The center conductor, the insulator core, and the foil thus form a central core portion of the cable received axially in the inner post, whereas the outer braided conductor and protective jacket comprise an outer portion of the cable surrounding the inner post. The conventional coaxial cable end connector further includes a connector body and/or compression member designed to coact with the inner post to securely and sealingly clamp the outer portion of the cable therebetween. The clamping to the jumper cable may be carried out by crimping, swaging or radial compression of connector body or compression sleeve by use of special tools adapted to mate with these components.

[0005] The second end of the connector typically includes an internally threaded nut rotatably secured to the connector body. The nut may be secured to a corresponding threaded port on the cable box, television, or other electronic device. The nut may be tightened using an appropriately sized wrench. To establish a reliable connection between the connector and the port, the nut must be threadedly advanced until a flange on the end of the post contacts then end face of the port.

[0006] One drawback to this tightening approach is that often space is very limited in the back of the electronic device and there is inadequate room for a wrench. For example, the cable box or television may be located within an entertainment console and access to port on the equipment may be limited. Or, access to a television housed in an entertainment console may be limited because the television may be too large or heavy to be moved.

[0007] Another drawback is that the person making the connection may be unaware of the proper method of establishing a reliable connection. In some instances, particularly when a wrench is unavailable, the user may cease hand-tightening after one or two turns. Although such a loose connection may provide adequate video signal, data transmission may be severely hampered or break down completely. Data transmission problems may affect voice over internet protocol (VOIP), for example.

[0008] In one aspect of the invention, an adapter sleeve for a coaxial cable connector transmits torque to a nut member on the cable connector. The adapter sleeve includes a cylindrical body having a first end and a second end defining a bore along a longitudinal axis therethrough. The bore defines an interior surface. The interior surface has a torque transmission feature sized to slideably engage the nut member. The first end of the body has at least one radially inward defined retainer lip. The retainer lip is dimensioned and adapted to engage with a corresponding retaining structure on an external surface of the nut member.

[0009] In another aspect of the invention, the torque transmission feature is the interior surface of the body having a hexagonal shape corresponding to the nut member.

[0010] In another aspect of the invention, the retainer lip is a continuous ring, and the corresponding retaining structure on the external surface of the nut is a retaining groove.

[0011] In another aspect of the invention, a method for positioning a coaxial cable connector on a port of an electrical device is provided. The connector includes a body and a nut member. The method comprises the steps of providing an adapter sleeve. The adapter sleeve includes a first end and a second end defining a bore along a longitudinal axis therethrough. The bore defines an interior surface. The interior surface has a torque transmission feature sized to slideably engage the nut member on the cable connector. The first end of the body has at least one radially inward defined retainer lip. The retainer lip is dimensioned and adapted to engage with a corresponding retaining structure on an external surface of the nut member. The method further includes the step of slideably engaging the adapter sleeve including the torque transmission feature over the cable connector in an axial direction, and engaging the retainer lip into the corresponding structure on the nut member to impede axial movement of the adapter sleeve relative to the nut member. The method further includes the step of positioning the cable connector and adapter sleeve to the port and turning the adapter sleeve to transmit torque to the nut member.

[0023] Referring to FIG. 1, an adapter sleeve 2 of the present invention is shown adjacent to a conventional coaxial cable connector 4. The coaxial cable connector 4 is shown adjacent to the prepared end of a coaxial cable 6. In the example illustrated, coaxial cable 6 can be a known coaxial type having an electrical center conductor 8 surrounded by and spaced radially inwardly from a braid conductor 10 by a foil 12 and an insulator core 14. A protective outer jacket 16 surrounds the braided outer conductor 10 and comprises the outermost layer of the cable. Although an exemplary coaxial cable has been described, the illustrated coaxial cable connector 4 can also be used with coaxial cables having configurations different from that disclosed above, such as quad-shield cable that may include multiple layers of foil and braid.

[0024] An end of the cable is prepared, as shown in FIG. 1, to receive the connector 4 by selectively removing various layers to progressively expose an end of the center conductor 8 and an end of the insulator core 14 and foil 12 as illustrated. An end portion of the braided conductor 10 is folded over protective outer jacket 16.

[0025] A variety of coaxial cable connectors may be adapted for use with the adapter sleeve of the present invention, such as the connectors described in U.S. Pat. No. 5,470,257 to Szegda or U.S. Pat. No. 6,153,830 to Montena, which are incorporated by reference herein in their entirety. Referring to FIG. 1, the connector 4 is configured and dimensioned to accommodate receiving the prepared end of a coaxial cable. The connector 4 has a first body member that includes connector body 18 and post member 20. The connector 4 also has a second body member which as shown is fastener member 22. The post member 20 may be a tubular member defining a first inner cavity 24. The inner surface of connector body 18 is radially spaced about the post member 20 to define a first outer cavity 26 accessible via opening 28 at one end of the connector body 18. The first outer cavity 26 is closed at the other end of connector body 18 together with post member 20.

[0026] Typically, the connector body 18 and the post member 20 are separate components wherein the connector body 18 is press fitted onto the outer surface of the post member 20. In an alternative preferred embodiment, the connector body 18 and post member 20 can be formed integrally as a single piece. Also, the connector body 18 can be formed of a plastic composition.

[0027] The inner surface of the connector body 18 has annular serrations 30 disposed opposite the post member 20. The post member 20 and annular serrations 30 of the connector body 18 provide for a continuous environmental seal and grip on the braid conductor 10 and protective outer jacket 16 of the cable when the fastener member 22 is in its second configuration.

[0028] As illustrated in FIG. 1, a nut member 32 is internally threaded and is provided with a shoulder 34 seated in a groove 35 formed by the outer surface of the base of post 20 and the connector body 18. The nut member 32 and post 20 are independently rotatable. An O-ring seal 36 can be seated in groove 35 of connector body 18 to serve as a moisture barrier. The nut member 32 further includes a cylindrical retaining groove 38 in an aft outer diameter 40 to accept a portion of the adapter sleeve 2, as will be explained below.

[0029] The fastener member 22 is movably coupled to the connector body 18 so as to be capable of being moved on the connector body 18 from a first preassembled configuration to a second assembled configuration. In a pre-installed first configuration as illustrated in FIG. 1, the fastener member 22 is fastened onto the connector body 18 such that the initial diameter is securely attached to the outer diameter of the connector body 18. In this manner, the fastener member 22, in its pre-installed first configuration, is securely fastened to the connector body 18 and is thus in an assembled state during storage, handling, and installation on a cable end.

[0030] The second configuration is achieved after the fastener member 22 is moved axially along the connector body 18 to a second location on the connector body 18 such that the smaller inner diameter of the fastener member 22 engages the outer surface of the connector body 18.

[0031] A method of positioning the connector on a coaxial cable is now described. The end of a coaxial cable is prepared by exposing a central core portion including the center conductor 8, insulator core 14, and foil 12. The outer braid conductor 10 is folded over the end of the outer protective outer jacket 16. The prepared end of the coaxial cable can be inserted through the second opening of fastener member 22 such that the central core portion including the center conductor 8, insulator core 14, and foil 12 is inserted into the first inner cavity 24 of post member 20. Also, the outer portion of the cable including outer braid conductor 10 folded over the end of the outer sheath jacket 16 is received into the first outer cavity 26 through opening 28.

[0032] Once the insulator core portion of the cable is positioned to abut the post member 20, the fastener member 22 is then advanced or moved axially from its pre-installed first configuration to its second configuration by a standard tool.

[0033] Since the smallest inner diameter of the fastener member 22 is smaller than the aft outer diameter of the connector body 18 accepting the fastener member 22, the connector body is concentrically gripped so that the volume of the first outer cavity 26 is further decreased. That is, the connector body 18 is further displaced or moved radially inwardly. As a result, the outer portion of the cable is firmly gripped or clamped between the outer surface of post member 20 and connector body 18. In this manner, the post member 20 cooperates with the annular serrations 30 of the connector body 18 to provide a generally continuous, 360 degree seal and grip on the outer portion of the cable.

[0034] The adapter sleeve 2 may be installed over the coaxial cable connector 4 once the fastener member 22 is in its second configuration. Alternatively, the adapter sleeve may be dimensioned and adapted so that the adapter sleeve may be placed over the connector before the fastener member 22 is axially advanced. After the adapter sleeve is placed over the connector, the nut member 32 may then be rotated to attach the connector to a system component—typically a threaded port or the like.

[0035] The adapter sleeve 2 includes a generally cylindrical body 42 having a first end 44 and a second end 46 defining a bore 48 along a longitudinal axis 50. The external surface of the body of the adapter sleeve may be textured to assist a user in turning the adapter sleeve 2 by hand. The texture may be grooved, splined, or knurled for example. Alternatively, the external shape of the adapter body 42 may be a prism, elliptic cylindrical, or have flats or concavities to assist the user in grasping and manipulating the adapter.

[0036] The bore 48 of the adapter sleeve body 42 defines an interior surface 43. The interior surface 43 includes a torque transmission feature in the first end 44 of the body 42. In one embodiment, the torque transmission feature defines a geometric shape to match the contour of the nut member 32. In the illustrated example and also as shown in FIG. 2, the torque transmission feature forms a hexagonal shape. The contour may be sized for a line-on-line fit with an outer contour 52 of the nut member 32. The compliant nature of the sleeve 2 allows it to be guided over the nut 32.

[0037] Referring to FIG. 3A, in another embodiment the torque transmission feature comprises a keyway 54. The keyway 54 may have a rectangular shape as shown, or alternately may be gear shaped or elliptical. Referring to FIG. 3B, the nut member 32 includes a corresponding key slot 56 to accept the keyway 54.

[0038] Referring to FIGS. 1 and 4A, the first end 44 of the body 42 further defines at least one retainer lip 58 having a radially inward orientation relative to the longitudinal axis 50. The retainer lip 58 is configured to engage a corresponding structure on an external surface of the nut member 32 to impede or prevent axial movement of the adapter sleeve 2 relative to the nut member 32. The retainer lip 58 and corresponding structure on the nut member 32 also serve to interfere with the removal of the sleeve 2. In one embodiment, the corresponding structure is the retaining groove 38. Thus, an inner diameter 60 of the retainer lip 58 is sized smaller than the outer diameter 40 of the nut member 32 but, due the flexibility of the sleeve material, the retainer lip 58 deflects until it engages the retaining groove 38. In one example, the inner diameter 60 is about 0.005-0.010 inches less than the outer diameter 40 of the nut member 32. In another example, a plurality of retainer lips 58 and retaining grooves 38 may be utilized to assure the adapter sleeve 2 will be difficult to remove.

[0039] In another embodiment, the retainer lip 58 may be segmented to further provide greater flexibility. As illustrated in FIG. 4B, the retainer lip 58 may comprise one or more tabs. In another example, the segments may comprise teeth (not shown).

[0040] Referring to FIG. 5, in yet another embodiment the retainer lip 58 may be inwardly offset a distance “D” from the first end 44 of the body 42. In this manner and referring to FIGS. 6A and 6B, the corresponding retaining groove 38 in the nut member 32 may be positioned at any convenient axial location, for example X1 or X2. As shown in FIG. 6C, the retaining groove 38 may alternately assume a conical shape.

[0041] Referring now to FIGS. 1 and 7, the corresponding structure on the external surface of the nut member 32 may be a protrusion 62. The retainer lip 58 engages the protrusion 62 to prevent axial movement of the adapter sleeve 2 relative to the nut member 32, in much the same manner as the retaining groove 38 in the example given above. Referring to FIGS. 8A and 8B, the protrusion 62 may include continuous or discontinuous structures such as annular radial protrusions, one or more arcuate protrusions, tabs, or detents on the exterior surface of the nut member.

[0042] The adapter sleeve 2 may be formed of a polyacetal engineered plastic such as Delrin®, manufactured by E.I. du Pont de Nemours and Company. In another embodiment, the sleeve 2 may be made of a pliable metal such copper.

[0043] In operation, the coaxial cable connector 4 may first be assembled to the coaxial cable 6 as described above. Next, the second end 46 of the adapter sleeve 2 may be aligned to the nut member 32 of the connector and pushed in the axial direction along the longitudinal axis 50 (e.g., in the direction of the arrow), over the nut, until the retainer lip 58 on the first end 44 of the sleeve engages corresponding structure on the nut member 32, which is the retaining groove 38 in the illustrated example. The cable assembly is then ready to be installed on the system component port such as a cable box. The completed assembly is illustrated in FIG. 9.

[0044] In another example, the adapter sleeve 2 may first be engaged over the coaxial cable connector 4 prior to installing the connector to the coaxial cable 6. This feature allows packaging the adapter sleeve 2 pre-assembled to the connector 4. This method may be adapted to a variety of coaxial cable connectors, as long as the installation tool does not interfere with adapter sleeve 2.

[0045] Because the interior surface 43 in the first end 44 of the body 42 defines a geometric shape matching the contour of the nut member 32, the adapter sleeve 2 effects torque transmission to the nut member 32. Thus, the nut may be hand-tightened without the use of a wrench. The outer contour of the cylindrical body 42 may include grooves 64, knurls, ribs, or other features to prevent slippage during the tightening or loosening operations. In one embodiment, the only radial contact surface between the adapter sleeve 2 and the coaxial cable connector 4 is at the nut member 32 interface. In the disclosed embodiment, the radial contact is limited to the hexagonal flats. As can be appreciated with reference to FIGS. 1 and 9, adequate clearance may be designed between the sleeve 2 and the connector body 18, and the sleeve 2 and the fastener member 22, so as to allow the nut member 32 to rotate freely without creating drag on other components of the connector 4. Furthermore, the retainer lip 58 may be designed to contact the retaining groove 38 only along side edges of the groove.

[0046] One advantage of the present invention is that a coaxial cable connector and jumper cable may be installed onto a corresponding electronic device without having to resort to the use of a wrench. This is particularly desirable when access to the electronic device is limited, or the device is housed in an enclosed space that is restricted. Further, a more secure and reliable connection may be established by use of hand-tightening. Without the adapter sleeve of the present invention, tightening the nut member on the port may be difficult, resulting in only a few threads being engaged. In contrast, using the adapter sleeve, greater torque transmission may be realized, resulting in a tighter, more secure connection.

[0047] One of the improvements of the present disclosure is that the sleeve remains fixedly engaged to the coaxial cable connector in the axial direction. That is, once the retaining rib snaps into the corresponding groove, the sleeve cannot easily be removed from the connector. This feature is particularly advantageous for pre-installed kits. For example, a broadband data provider may choose to provide customers with installation kits and instructions so the customer can connect a cable modem, for example, to an existing coaxial network. Inclusion of coaxial connectors with pre-installed adapter sleeves of the present invention will greatly increase the likelihood that the customer will correctly connect the connector to the port. This, in turn, saves the broadband data provider a service call to the premises in the event the installation was performed improperly.

[0048] In contrast, other sleeve designs having raised surfaces (e.g., hemispherical bumps or the like) on the internal contour of the bore tend to slip during tightening operations. Also, the raised surfaces, being quite small in overall surface area, tend to wear away with only a few installation and removal operations. Once worn away, the sleeve becomes free to move in the axial direction and hampers tightening operations.

[0049] Another improvement of the disclosed adapter sleeve is that it is easier to manufacture. In one example, the adapter sleeve is formed in a molding process such as injection molding. Prior art sleeve adapters included one or more hemispherical protrusions on one of the hexagonal interior surfaces, approximately at location “A” in FIG. 2. The protrusions were positioned such that they would flatten out as the sleeve moved over the nut member, and upon clearing the nut would pop out to the original shape in order to retain the sleeve in the axial direction. One problem with this approach was that the hemispherical protrusion represented an undercut in the mold die. Thus, for the same reason the protrusion acted as an effective axial retainer with the nut, it was also difficult to eject from the mold die. Hence, the protrusion was often damaged during the ejection phase of the mold process. In contrast, the retainer lip of the present invention presents no such problems during the molding process because the lip is formed where the mold die halves come together. Thus, the retainer lip never has to pass over any part of the mold in order to be ejected.

[0050] While the present invention has been described with reference to a particular preferred embodiment and the accompanying drawings, it will be understood by those skilled in the art that the invention is not limited to the preferred embodiment and that various modifications and the like could be made thereto without departing from the scope of the invention as defined in the following claims.