Cable connector system for shielded cable

A cable connector assembly includes a ferrule assembly configured for attachment to a cable braid, and a resilient contact element surrounding an end of the ferrule assembly. A retaining band clamps the cable braid to the ferrule assembly. A conductive shell is configured to compress the resilient contact element.

BACKGROUND OF THE INVENTION

This invention relates generally to electrical connectors, and more specifically to cable connector assemblies for use with shielded cables having metallized braids.

Some electrical systems include shielded cable assemblies for transmitting electrical signals. Conductive metallized braids are coupled to the cable and surround the signal conductors in the cable for shielding purposes, and the metallized braids are connected to shielding features of connectors and components which ultimately provide a conductive path to ground. The metal braids of the cables, however, tend to complicate termination of the cables to connectors, and also complicate interconnection of the cables with other electrical components.

In systems of this type, connectors for shielded cables often include conductive metal shells, and some conventional metal shells include integral ferrule surfaces formed therewith which aid in connecting the cable braid to the shells. The cable braid is extended over the ferrule surfaces of the shells, and outer ferrule elements are attached over and crimped to the cable braid, thereby trapping the cable braid between the ferrule surfaces of the shell and the outer ferrule elements. While a satisfactory mechanical and electrical connection between the cable braid and the shells may result in such a construction, the ferrule surfaces of the shells are vulnerable to being damaged during assembly of the connector. Damage to the ferrule surfaces can compromise the performance of the cable connector and present reliability and performance issues, or cause the cable connector to be scrapped altogether, thereby reducing manufacturing efficiency and raising the costs of production.

Further, some electrical cables include a large conduit with a large number of conductors therein, and terminating the cable conductors to a connector and successfully connecting the cable braid to the shell is difficult. For example, at least one known connector is configured for attachment to as many as forty cable conductors. In such circumstances, the cable can become difficult to handle when the cable connector is installed, thereby increasing the risk that the ferrules will be damaged as the connector assembly is assembled.

BRIEF DESCRIPTION OF THE INVENTION

According to an exemplary embodiment, a cable connector assembly comprises a ferrule assembly configured for attachment to a cable braid, and a resilient contact element surrounding an end of the ferrule assembly.

Optionally, a retaining band at one end of the ferrule assembly clamps the ferrule assembly to the cable braid. A radial groove may be provided in the cable assembly, and the resilient contact element is located in the radial groove. The ferrule assembly may be fixedly mounted to the conductive shell to prevent rotation of the ferrule assembly with respect to the shell, and the ferrule assembly may comprise a 90° bend. A conductive shell may be provided, and the conductive shell may be configured to compress the resilient contact element. The resilient contact element may comprise a canted coil spring.

According to another exemplary embodiment, a cable connector assembly comprises a conductive shell, and a ferrule assembly configured for attachment to a cable braid. The ferrule assembly extends from the conductive shell, and a compressible contact element encircles the ferrule assembly within the conductive shell. The contact element establishes an electrical connection to the shell when compressed.

According to still another exemplary embodiment, a cable connector assembly comprises first and second conductive shell elements, and each of the first and second conductive shells comprise an arcuate slot having a curved engagement surface. A ferrule assembly comprises first and second ferrule elements configured to attach to a cable braid, and the ferrule assembly comprises a radial groove. A resilient contact element extends circumferentially on the ferrule assembly within the radial groove, and the first and second shell elements compress the resilient contact element when the contact element is inserted into the slot and when the first and second shell elements are fastened together.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is an exploded view of a cable connector assembly100formed in accordance with an exemplary embodiment of the present invention. The connector assembly100is particularly useful with shielded cables as explained below, and may be installed to shielded cables in a direct and reliable manner which avoids the aforementioned difficulties and disadvantages of known cable connectors when used with shielded cables.

As shown inFIG. 1, in an illustrative embodiment the cable connector assembly100includes an inner ferrule assembly102, a cable connector104, upper and lower shells106and108, and a ground shield assembly110. The upper and lower shells106,108receive the inner ferrule assembly102and the cable connector104, and the ferrule assembly102establishes a reliable electrical connection to the upper and lower shells106,108while alleviating manufacturing and assembly difficulties of known cable connectors. Specifically, the ferrule assembly102assures adequate electrical contact with the upper and lower shells106and108, and may be reliably manufactured and assembled in a straightforward and cost effective manner without damage to the components of the assembly.

The ferrule assembly102is attached to a conductive metallized braid112of a cable114in the manner explained below. The ferrule assembly102is received within a first compartment116defined by the upper and lower shells106,108when the cable connector assembly100is assembled. The cable connector104is electrically connected or terminated to conductors in the cable114, and the cable connector104is received in a second compartment118defined by the upper and lower shells106,108when the connector assembly100is assembled.

In an exemplary embodiment, the cable connector104is a known connector which is mechanically and electrically connected or terminated to conductors in the cable114in a known manner. As such, and in an exemplary embodiment, the cable connector114provides interconnection of high-speed, low-voltage, differential signals between the cable114and a backplane connector (not shown inFIG. 1) mounted in, for example, a computer server system. In one such embodiment, the cable connector104is as a Z-PACK Hm-Zd cable connector that is commercially available from Tyco Electronics Corporation of Harrisburg, Pa. Other cable connectors may be utilized, however, in alternative embodiments, provided that they are compatible the backplane or mating connector of the computer system.

In an exemplary embodiment, each of the upper and lower shells106,108are fabricated from a conductive material, such as die cast metal, and the shells106and108form a protective enclosure about the ferrule assembly102and the cable connector104when the shells106and108are coupled to one another. The upper and lower shells106and108are generally rectangular in shape and are sized and dimensioned to securely receive and retain the ferrule assembly102and the connector104. The upper and lower shells106and108are fitted over one another and mechanically connected to one another with known fastener elements120, such as screws or rivets. The upper and lower shells106,108are formed with mounting flanges122which receive mounting fasteners124, such as jack screws shown inFIG. 1. The cable connector100can be securely mated, via the mounting fasteners124, to a header assembly (described below) that is mounted to, for example, a frame of a computer chassis.

The upper shield106includes shield retaining projections125adjacent a forward end126thereof. Each of the upper and lower shells106,108include a curved or arcuate slot127which accommodates a portion of the ferrule assembly102. The first compartment116of the upper and lower shells106,108includes a rounded engagement surface128which supports and compresses an outer surface of the ferrule assembly102as explained below.

The ground shield assembly110includes U-shaped frame elements130that are dimensioned to be attached to and substantially surround the forward end126of the upper shell106and a forward end132of the lower shell108. Each of the frame elements130includes grounding fingers or tabs134which extend inwardly into the second compartment118of the upper and lower shells106,108to contact the outer surfaces of a header shield206(described below in relation toFIGS. 5 and 6). Each of the frame elements130also includes a retention aperture136which cooperates with the retention projections125of the upper shell106to mechanically connect the frame elements130to the upper and lower shells106,108.

FIGS. 2 and 3are exploded and assembled views, respectively, of the ferrule assembly102. The ferrule assembly102includes the cable braid112, first and second ferrule elements142and144, a retaining band146, and a resilient contact element148.

The cable braid112is substantially cylindrical as shown inFIGS. 2 and 3, is externally applied to the cable in a known manner and surrounds inner conductors in the cable. The ferrule elements142and144each include respective semi-cylindrical inner surfaces152and154that are fitted over a forward end156of the cable conductors114, and the inner surfaces152,154of the ferrule elements142,144engage the outer surfaces of the conductors. The ferrule elements142and144further include first and second retaining rims157,158and160,162, respectively, which extend radially outwardly from the inner surfaces152and154and define respective grooves164,166therebetween. The groove164,166extend radially around the circumference of the outer surface of the ferrule elements142and144.

A retaining lip170extends outwardly from the respective inner surfaces152and154at a distance from the radial grooves164and166of the respective ferrule elements142and144. The ferrule elements142and144are separately formed and fabricated from one another in a known die cast metal process. The ferrule elements142, and144are essentially mirror images of one another, and are snap fit to one another over the end156of the cable conductors114as shown inFIG. 3. Snap fit engagement of the ferrule elements142and144is provided via mounting pegs172and apertures174formed into the ferrule elements142and144. The ferrule elements142,144are received over the outer surface145of the cable conductors and do not contact an inner surface of the cable conductors during installation. The ferrule elements142,144are therefore rather easily assembled in comparison to convention connector assemblies.

Once the ferrule elements142,144are in place on the cable, the braid112may be drawn over the ferrule elements up to retaining rims162,158and be clamped to the ferrule assembly in a straightforward manner with the retaining band146. The retaining band146in an exemplary embodiment is a known clamp element having an adjustable stainless steel ring180and buckle182which compresses the end156of the cable braid112onto the ferrule elements142and144. One such retaining band is a commercially available BAND-IT clamping system of Band-It-Idex, Inc. of Denver, Colo. The ring180is extended over cable braid112and the ferrule elements142,144between the respective retaining lips168,170and the rims158,162. Once located over the ferrule elements142and144, the ring180is tightened over the ferrule elements142,144and the buckle182latches the ring180in place to attach the cable braid112to the ferrule elements142,144.

The resilient contact element148is toroid shaped and is dimensioned so that it may be received in the radial grooves164,166of the ferrule elements142and144. As shown inFIG. 3, the contact element148extends circumferentially and encircles one end of the ferrule elements140,142when located in the radial grooves164,166. The contact element148protrudes outwardly from the grooves164,166such that the contact element148is in contact with and compressed by the rounded engagement surfaces128of the upper and lower shells106,108(FIG. 1) when the shells106,108are coupled to one another.

The resilient contact element148in an exemplary embodiment is a canted-coil spring having inclined or canted coils that deflect independently when compressed. As such, the entire spring element responds wherever any portion of a coil is deflected by the upper and lower shells106,108, thereby permitting uniform loading at each contact point. Additionally, the canted coil spring presents a large number of contact points with the upper and lower shells106,108(FIG. 1) when the contact element148is received in the slots127(FIG. 1) and in abutting engagement contact with the engagement surface128(FIG. 1). Such canted springs are commercially available from, for example, Bal Seal Engineering Co., Inc. of Foothill Ranch, Calif. It is recognized, however, that other contacts elements may be employed in alternative embodiments.

When compressed, the resilient contact element148maintains secure mechanical and electrical engagement between the upper and lower shells106and108and the ferrule elements142and144, while the retaining band146maintains secure mechanical and electrical engagement between the ferrule elements142,144and the cable braid112. The ferrule elements142,144, and the resilient contact element148permit some flexibility in assembling the connector100, particularly with regard to terminating the cable conductors to the connector104(FIG. 1). More specifically, and unlike known connector assemblies, the cable braid112may be connected to the upper and lower shells106,108after the cable is terminated to the connector104, and ferrule surfaces in the conductive shells are unnecessary to establish an electrical connection to the braid112. Further, because the ferrule elements142,144are installed over the exterior of the cable conductors114, they may be installed rather easily with little risk of damage. The contact element148is easily installed to the ferrule elements142,144and provides reliable electrical connection to the upper and lower shells106,108when the upper and lower shells106,108are joined without being separately connected to the shells106,108prior to coupling the shells together.

FIG. 4illustrates the completed cable connector assembly100with the upper shell106coupled to the lower shell108and enclosing the ferrule elements142and144(FIGS. 2 and 3) and the cable connector104. The ground shield assembly110is attached the upper and lower shells106,108adjacent a connector face150of the connector104which receives mating contacts (not shown inFIG. 4) of a header assembly (described below). The cable braid112extends from the upper and lower shells106,108at an end thereof opposite the connector face150. The mounting fasteners124extend alongside and partly through the upper and lower shells106and108and may be received in mounting apertures of, for example, a computer chassis frame near the mating header assembly. While jack screws are illustrated inFIG. 4, it is recognized that other types of mounting fasteners124may be employed in other embodiments to mount the connector assembly102in a predetermined location.

FIGS. 5–7illustrates a header assembly200which may be used with the cable connector assembly100shown inFIGS. 1–4. The header assembly200includes a known backplane connector202that is connected to a printed circuit board204in a known manner. In an exemplary embodiment, the backplane connector204provides interconnection of high-speed, low-voltage, differential signals between the printed circuit board204and the cable connector assembly100. In one such embodiment, the backplane connector204is as a Z-PACK Hm-Zd right angle backplane connector which is commercially available from Tyco Electronics Corporation of Harrisburg, Pa. Other cable connectors which are compatible with the cable connector assembly100may be utilized, however, in alternative embodiments.

A header shield206substantially surrounds the backplane connector202and is attached to printed circuit board204with fasteners208as shown inFIG. 6. The header shield206includes a mounting rim210having mounting tabs212with apertures therethrough. The shield206may be fabricated from, for example, die cast metal in a known manner. While female screw locks are illustrated as the fasteners208, it is appreciated that other fasteners may be employed in alternative embodiments.

A connector interface panel220includes a number of cutouts or apertures222which are dimensioned to receive a front shroud224of the header shield206as shown inFIG. 7. Fasteners226are inserted through the panel220above and below the front shroud224, and the fasteners226engage the mounting tabs212to mechanically connect the header assembly200to the panel220. In the illustrated embodiment, the panel220includes three cutouts222and may therefore accommodate three header assemblies200in a side-by-side configuration. It is recognized, however, that the panel220may include greater or less than three cutouts222in alternative embodiments to accommodate different numbers of header assemblies200.

The panel220may be mounted to, for example, a chassis (not shown) of a computer system and serve as an input/output port for communicating with circuit boards in the chassis via header assemblies200. Once the header assembly200is mounted to the panel220, the cable connector assembly100(FIGS. 1–4) may be plugged into the shroud224to mate the cable connector104(FIGS. 1 and 4) to the header assembly200(FIGS. 5–7). The mounting fasteners124, such as the jack screws shown inFIGS. 1 and 4may be connected to the female fasteners226extending above and below the shroud224to securely latch or retain the cable connector assembly100to the panel220in electrical engagement with the header assembly200.

FIG. 8is a perspective view of another embodiment of a cable connector assembly300which may be used with, for example, the header assembly200(shown inFIGS. 5–7).

The cable connector assembly300includes an inner ferrule assembly302, a cable connector304, upper and lower shells306and308which receive the inner ferrule assembly302and the cable connector304, and a ground shield assembly310.

The ferrule assembly302is attached a conductive metallized braid312of a cable314, and the ferrule assembly302is received within a first compartment316defined by the upper and lower shells306,308. The cable connector304is electrically connected to conductors in the cable, and the cable connector304is received in a second compartment318defined by the upper and lower shells306,308. The ferrule assembly302includes approximately a 90° bend in an illustrative embodiment, although the ferrule assembly may include a bend of greater or less than 90° in an alternative embodiment.

In an exemplary embodiment, the cable connector304is a known connector which is mechanically and electrically connected or terminated to conductors in the cable. As such, and in an exemplary embodiment, the cable connector304provides interconnection of high-speed, low-voltage, differential signals between the cable and a backplane connector, such as the connector202(FIG. 5) of, for example a computer server system. In one such embodiment, the cable connector304is as a Z-PACK Hm-Zd cable connector which is commercially available from Tyco Electronics Corporation of Harrisburg, Pa. Other cable connectors which are compatible with a backplane connector may be utilized, however, in alternative embodiments.

In an exemplary embodiment, each of the upper and lower shells306,308are fabricated from a conductive material, such as die cast metal, and the shells306,308form a protective enclosure about a portion of the ferrule assembly302and the cable connector304when the shells306and308are coupled to one another. The upper and lower shells306,308are sized and dimensioned to securely receive and retain the ferrule assembly302and the connector304, and the upper and lower shells306,308are mechanically connected to one another with known fastener elements such as screws or rivets.

The connector assembly300further includes side insulating shells320and322which are fabricated from plastic, for example, and snap together over the upper and lower shells306and308. The side insulating shells320and322are formed with connector flanges324which receive mounting fasteners326, such as jack screws shown inFIG. 8, so that the cable connector300can be securely mated to a header assembly mounted in, for example, a frame of a computer chassis.

The upper shield306includes shield retaining projections328adjacent a forward end330thereof. The ground shield assembly310includes L-shaped frame elements332which are dimensioned to be attached to and substantially surround the forward end330of the upper shell306and a forward end334of the lower shell308. Each of the frame elements332includes grounding fingers or tabs334which contact the outer surfaces of mating header shield (not shown inFIG. 8). Each of the frame elements332also includes retention apertures335which cooperate with the retention projections328of the upper shell306to mechanically connect the frame elements332to the upper and lower shells306and308.

FIG. 9illustrates the ferrule assembly302including a first ferrule element340and a second ferrule element342which are formed as mirror images of one another and snapped together to define a substantially continuous sleeve which receives the cable braid312(FIG. 8) at one end344. A retaining band clamp346is located adjacent the end344of the ferrule assembly302and is tightened or clamped to the outer surface of the cable braid312. A resilient contact element348extends on the opposite end350of the ferrule assembly302, and the contact element348extends between radially projecting rims352,354formed in the ferrule elements340and342. In an illustrative embodiment, the retaining band clamp346is BAND-IT clamp as described above, and the contact element348is a canted coil spring as described above. Different clamps or fasteners and/or different contact elements may be employed in alternative embodiments, however, as desired.

The ferrule element340includes a locating projection360adjacent the rim352which cooperates with a complementary shaped notch362(FIG. 8) in the upper shell306to fix the relative orientations of the ferrule assembly302and the upper and lower shells306,308. When the projection360is received in the notch362, the ferrule assembly302is prevented from moving or rotating relative to the upper and lower shells306,308and associated stress on the cable and connector due to relative movement of the cable with respect to the connector304is avoided. The locating projection360and the notch362may be positioned in various locations on the ferrule assembly302and the upper shell306, respectively, to orient and lock the ferrule assembly302in different positions relative to the upper and lower shells306and308. Multiple notches362may be utilized to enhance tooling flexibility.

FIG. 10illustrates the ferrule assembly302resting in one end of the upper shell306. The resilient contact element348is received in a curved or arcuate slot360having a curved engagement surface formed in the end of the shell306, and the contact element continuously engages the curved engagement surface of the slot360. The lower shell308(FIG. 8) includes a similar slot having a curved engagement surface, and when the shells306,308are coupled to one another, the slots of the respective shells compress the contact element348to ensure electrical contact between the contact element348and the shells306,308.

FIG. 11illustrates the completed cable connector assembly300with the side insulating shells320,322encapsulating and enclosing the upper and lower shells306and308, portions of the ferrule elements340and342(FIG. 9), and the cable connector304(FIG. 8). The ground shield310is attached the upper and lower shells306,308. The cable braid312extends from the ferrule elements340and342at an end thereof opposite the connector face of the cable connector304. The mounting fasteners326extend alongside the upper and lower shells306,308and partly through the side insulating shells320and322. While jack screws are illustrated inFIG. 4, it is recognized that other types of mounting fasteners326may be employed in other embodiments to mount the connector assembly300in a predetermined location.

The ferrule assembly302and contact element348permits a straightforward and lower cost assembly than known cable connectors while avoiding potential damage to the components during assembly. Reliable electrical contact between the cable braid312and the ferrule assembly302is ensured, and manufacturing and assembly costs are saved.