Magnetic connector having a unitary housing

BACKGROUND

0001Portable electronic devices have become increasingly popular the past several years. Laptop and netbook computers, cell phones, portable media devices, and the like have become ubiquitous, and soon notebook and tablet computing devices will follow.

0002These devices include batteries that provide power. Unfortunately, these batteries need recharging. This recharging is often performed using a power cable having a connector insert or cable plug that mates with a connector receptacle on the portable device. Power can be supplied by a power transformer that receives power from a wall outlet, vehicle charging outlet, or other source. The power transformer converts the power from the outlet to a power level that can be used to charge the battery in a portable device. In some circumstances, these power cables may also convey signals between the portable device and a second electronic device.

0003The connector insert or cable plug may include circuitry inside of a plug housing. The plug housing typically is formed using several pieces that fit together around the circuitry. This patchwork of pieces used to form a plug housing can result in a housing having a less than optimal appearance.

0004The cable can include a conductor surrounded by an insulating layer. This conductor can be used to convey a power supply, such as a positive power supply voltage. The insulating layer can be further surrounded by a metallic braid layer that is used to convey ground. The braiding may be covered with a polyvinyl chloride coating. This coating provides a fire resistance to protect the electronic device in the event that the power transformer overheats or catches on fire. However, for various reasons, it is environmentally undesirable to use materials such as polyvinyl chloride. Unfortunately, halogen-free cables do not provide adequate fire resistance.

0005Thus, what is needed are improved power cables that have plug housings that provide an improved appearance as well as employ a halogen-free cable while providing adequate fire resistance.

SUMMARY

0006Accordingly, embodiments of the present invention provide power cables that include cable plug housings having an improved appearance as well as employing a halogen-free cable while providing adequate fire resistance.

0007A specific embodiment of the present invention provides a power cable having a cable plug or connector insert with a unitary (made from a single piece) or substantially unitary body. This body provides an improved appearance, greater strength and durability, and is simple to manufacture at a reduced cost. The cable plug can receive a power cable and may provide contacts for power transmission. The housing may be substantially unitary, that is, it may be made predominantly using a single piece of material. The single piece of material may be formed using metal, such as aluminum. The single piece of material may alternately be formed using plastic, ceramic, or other material. The single piece may be approximately cylindrical, or it may have other shapes, such as oval, square, or other shapes or combinations of shapes.

0008The contacts or terminals may extend from the cable plug housing and may be protected by a protrusion that mates with a connector receptacle on an electronic device. In various embodiments of the present invention, the protrusion is a magnetic element that is attracted to a second magnetic element in the connector receptacle. These magnetic elements may be magnets, attraction plates, or other types of magnetic elements, such as electromagnets. The attraction plates may be formed using a ferromagnetic material. In a specific embodiment of the present invention, the connector insert protrusion can include an attraction plate that is attracted to a magnetic element located in the connector receptacle.

0009Another specific embodiment of the present invention provides a power cable that is formed using halogen-free materials. To provide adequate fire protection, a strain relief formed using multiple materials is used. This strain relief can provide an interface between the cable and a housing, for example, a housing enclosing a power transformer. The strain relief can include a first, interior portion formed using a rigid, fire-resistant material. The fire-resistant material may be a polycarbonate, polycarbonate ABS (PC/ABS) blend, or other appropriate material. The strain relief may include a second, exterior portion formed using a flexible material. This material may be a thermoplastic elastomer (TPE), fluorinated ethylene propylene (FEP), or other appropriate material.

0010Various embodiments of the present invention may incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention may be gained by reference to the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

0011<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates a power cable assembly according to an embodiment of the present invention;

0012<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates a cable plug according to an embodiment of the present invention;

0013<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates components that may be used to construct a cable plug according to an embodiment of the present invention;

0014<figref idrefs="DRAWINGS">FIG. 4</figref> illustrates a side view of a portion of a cable plug according to an embodiment of the present invention;

0015<figref idrefs="DRAWINGS">FIG. 5</figref> illustrates portions of a strain relief according to an embodiment of the present invention; and

0016<figref idrefs="DRAWINGS">FIG. 6</figref> illustrates a strain relief according to an embodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

0017<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates a power cable assembly <b>100</b> according to an embodiment of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit either the possible embodiments of the present invention or the claims.

0018Power cable assembly <b>100</b> may be used for providing power to an electronic device, such as a laptop, netbook, notebook, tablet computer, media player, portable media player, cell phone, or other type of electronic device. Cable assembly <b>100</b> may also be used to convey signals between such devices. Cable assembly <b>100</b> may include cable plug <b>105</b> and strain relief <b>140</b> connected together via cable <b>150</b>.

0019Cable plug <b>105</b> may mate with a compatible connector receptacle (not shown.) Cable plug <b>105</b> may include housing <b>110</b>, attraction plate <b>125</b>, and strain relief <b>115</b>. Housing <b>110</b> may be unitary or substantially unitary. This unitary construction can provide a connector plug <b>105</b> having an improved appearance, increased strength, and reduced manufacturing costs. Housing <b>110</b> may be formed using metal, such as aluminum, plastic, ceramic, or other material.

0020Attraction plate <b>125</b> may be formed around contacts <b>130</b>. Attraction plate <b>125</b> may have two axes of symmetry, allowing cable plug <b>105</b> to mate with a compatible connector receptacle in at least two orientations. Attraction plate <b>125</b> may be formed of metal, plastic, ceramic, or other material. For example, the attraction plate may be made using a ferromagnetic material.

0021A dust cover (not shown) may cover the sides of attraction plate <b>125</b> and the contacts <b>130</b>. The dust cover may be formed using metal, plastic, ceramic, or other material. For example, it may be formed of a transparent plastic. The dust cover may form a seal, reducing or eliminating the amount of dust particles entering housing <b>110</b> when cable assembly <b>100</b> is transported. To prevent the loss of the dust cover, the dust cover may be attached to the cable assembly <b>100</b> by a tie, cord, wire, or other fastener.

0022Contacts <b>130</b>, which may also be referred to as signal terminals or pins, may include contacts for signal and power supplies, such as power and ground. Cable plug <b>105</b> can include five such contacts, though in other embodiments of the present invention, other numbers of contacts may be included. For example, three contacts may be included. Also in other embodiments of the present invention, one or more contact for fiber-optic cables may be included. The center pin may be a detect pin that detects that cable plug <b>105</b> has mated with a compatible connecter receptacle. Two ground pins may be located on each side of the detect pin. Two power supply pins may be located on each side of the detect pin between the detect pin and the ground pins. Alternately, the ground pins may be located between the power supply pins and the detect pin. The contacts may be retractable, that is, they may be biased, for example by a spring.

0023Cable plug <b>105</b> can include a strain relief <b>115</b>. Strain relief <b>115</b> may be formed of a flexible material. For example, it may be made of a halogen-free material. In a specific embodiment of the present invention, it can be formed using a thermoplastic elastomer, fluorinated ethylene propylene, or other appropriate material.

0024Strain relief <b>140</b> and cabling <b>152</b> can form a pigtail that may be used to connect power cable assembly <b>100</b> to a power supply. For example, the pigtail may be housed in an enclosure that includes a power transformer or other circuitry. For example, the enclosure may have power prongs or other connections to receive power from a wall socket, vehicle outlet, or other power supply. Circuitry internal to the housing can convert the received power supply to a power level appropriate for the electronic device to be charged. Cabling <b>152</b> may connect to this power conversion circuitry, such as a power transformer that converts AC power to DC power. Alternately, cabling <b>152</b> may connect to power conversion circuitry that converts a first DC power supply to a second DC power supply. The housing may also include wired or wireless data communications and other electronic circuits. Cabling <b>152</b> may include further connections for these circuits.

0025Strain relief <b>140</b> can include an interior portion <b>145</b> and exterior portion <b>147</b>. Interior portion <b>145</b> may be inside the housing (not shown) that also includes the power transformers or other electrical components. Exterior portion <b>147</b> may be located outside of this housing. Inside portion <b>145</b> may be formed using a hard plastic, such as a polycarbonate, polycarbonate ABS blend or other appropriate material, for fire protection. Exterior portion <b>147</b> may be formed using a more flexible material, such as a thermoplastic elastomer, fluorinated ethylene propylene, or other appropriate material.

0026Strain relief <b>140</b> may provide an interface between cable <b>150</b> and the housing. Strain relief <b>140</b> can allow cable <b>150</b> to be flexed or moved relative to the housing, such that cable <b>150</b> does not wear excessively. Strain relief <b>115</b> can similarly protect cable <b>150</b> at its interface with cable plug <b>105</b>.

0027Cable <b>150</b> may be formed with an inside conductor surrounded by a metallic braiding. The inside conductor may be used to convey power, while the braiding may be used to convey ground. Isolation layers may be included between the inside conductor and the braiding, and outside of the cable around the braiding. Cable <b>150</b> may be made of a halogen-free material. For example, it may be formed using a thermoplastic elastomer, fluorinated ethylene propylene, or other appropriate material. Cable <b>150</b> may include additional conductors for conveying signals, for example, those provided by wired or wireless data communications and other electronic circuits located in the housing that includes the power transformer or conversion circuitry. Cable <b>150</b> may also include one or more fiber-optic cables.

0028Again, it is desirable to provide a cable plug <b>105</b> having an attractive appearance, and that is durable and easy to manufacture. Accordingly, embodiments of the present invention provide a cable plug <b>105</b> having a unitary or substantially unitary housing. An example is shown in the following figure.

0029<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates a cable plug <b>205</b> according to an embodiment of the present invention. Cable plug <b>205</b> may also be referred to as a connector insert. Cable plug <b>205</b> can include housing <b>210</b>, attraction plate <b>225</b>, contacts <b>230</b>, and strain relief <b>215</b>. Cable <b>250</b> can attach to cable plug <b>205</b>. Attraction plate <b>225</b> can protect contacts <b>230</b> and can be magnetically attracted to magnets located in a compatible connector receptacle. A dust cover (not shown) may be employed to prevent particulate matter from entering housing <b>210</b> when the cable assembly is transported. Housing <b>210</b> may also include a light-emitting diode (LED) exit <b>212</b>. Exit <b>212</b> may allow light from an LED inside housing <b>210</b> to escape. In a specific embodiment of the present invention, a lit LED may indicate that an electrical connection has been made between cable plug <b>205</b> and a compatible receptacle (not shown.)

0030Housing <b>210</b> may be unitary, though in other embodiments of the present invention it may be substantially unitary. In this example, housing <b>210</b> is cylindrical, though in other embodiments of the present invention housing <b>210</b> may have other shapes. Housing <b>210</b> may provide an attractive appearance, and may be durable and easy to manufacture. Housing <b>210</b> may be metallic, plastic, ceramic, or formed using another material. In a specific embodiment of the present invention, housing <b>210</b> is made of aluminum.

0031Attraction plate <b>225</b> may have two axes of symmetry, allowing cable plug <b>205</b> to mate with a compatible connector receptacle in at least two orientations. The attraction plate may be metallic, such that it is attracted to magnets inside the connector receptacle. These magnets may have opposing polarities, such that magnetic field lines that originate in one magnet travel through attraction plate <b>225</b> and terminate in a second magnet. Attraction plate <b>225</b> can, for example, be formed using a ferromagnetic material. In other embodiments of the present invention, attraction plate <b>225</b> may be formed using one or more magnets, such as rare-earth magnets or electromagnets.

0032A dust cover (not shown), may be arranged to cover attraction plate <b>225</b> and contacts <b>230</b>. The dust cover may be formed using metal, plastic, ceramic, or other material. For example, the dust cover may be made of a transparent plastic. This transparent plastic may be colored to provide a pleasing appearance.

0033Contacts <b>230</b> may be pogo pins or other types of contacts. Contacts <b>230</b> may include a center contact. The center contact may be a detect pin. Alternately, it may be a fiber-optic connection, signal pin, or other type of contact, signal terminal, or pin. The two contacts <b>230</b> on each side of the center pin may convey a positive power supply, though they may alternately convey ground. The two outside contacts <b>230</b> may convey ground, though they may alternately convey a positive power supply. Contacts <b>230</b> are typically metallic, such that they are conductive. Contacts <b>230</b> may be formed using brass, copper, or other metals.

0034Strain relief <b>215</b> can protect cable <b>250</b> from excessive wear that could otherwise result at the interface with housing <b>210</b> when cable <b>250</b> is moved or flexed relative to housing <b>210</b>. Strain relief <b>215</b> may be formed using a flexible material, such as a thermoplastic elastomer, fluorinated ethylene propylene, or other appropriate material.

0035Again, it is desirable that cable plug <b>205</b> be robust and simple to manufacture. An example of the components that may be used to construct cable plug <b>205</b> according to an embodiment of the present invention is shown in the following figure.

0036<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates components that may be used to construct a cable plug <b>305</b> according to an embodiment of the present invention. Cable plug <b>305</b> may include housing <b>310</b>, strain relief <b>315</b>, cable <b>350</b>, crimping ring <b>355</b>, assembly <b>340</b>, contacts <b>330</b> and <b>332</b>, front plate <b>335</b>, attraction plate <b>325</b>, dust cover <b>320</b>, circuit board <b>360</b>, LEDs <b>365</b>, light pipes <b>370</b>, and light insulators <b>380</b>.

0037Housing <b>310</b> may include an LED exit <b>312</b>. LED exit <b>312</b> may be an actual hole, or it may be a number of small perforations. In a specific embodiment of the present invention, these perforations may be on the order of 0.03 mm in size. At this size, the individual perforations may not be not visible unless light is emitting through them. Again, housing <b>310</b> may be metal, for example aluminum, plastic, ceramic, or it may be made of another material.

0038Strain relief <b>315</b> may receive cable <b>350</b>. Strain relief <b>315</b> can be flexible and may prevent housing <b>310</b> from wearing cable <b>350</b> as cable <b>350</b> moves relative to housing <b>310</b> during use. Strain relief <b>315</b> may be made of a flexible material, such as a thermoplastic elastomer, fluorinated ethylene propylene, or other flexible material.

0039Cable <b>350</b> passes through strain relief <b>315</b>. Cable <b>350</b> may include a center conductor for providing a positive power supply. Cable <b>350</b> may include other conductors, fiber-optic cables, or other signal or power conduits. The center conductor may be insulated and surrounded by a metallic braiding. The metallic braiding may be used to covey ground. The metallic braiding may be further insulated. Various embodiments of the present invention use a halogen-free coating or jacket, such as a coating formed using a thermoplastic elastomer, or other appropriate material.

0040Crimping ring <b>355</b> can crimp cable <b>350</b>. Crimping ring <b>355</b> may be metallic, plastic, or formed using other materials. Crimping ring <b>355</b> may prevent cable <b>350</b> from splitting due to stresses that may result with usage. Crimping ring <b>355</b> may also provide strain relief. In various embodiments of the present invention, crimping ring <b>355</b> may connect mechanically and (or) electrically to any or all of the metal braiding of cable <b>350</b>, assembly <b>340</b>, contacts <b>345</b>, or circuit board <b>360</b>.

0041Assembly <b>340</b> may attach to cable <b>350</b> at contacts <b>345</b>. For example, the inside conductor and braiding of cable <b>350</b> may attach to assembly <b>340</b> at contacts <b>345</b>. Contacts <b>345</b> may be located on each side of a portion of assembly <b>340</b>. Assembly <b>340</b> may be formed using an insulating material, such that an insulative housing is formed. Contacts <b>345</b> may connect to conductive leads internal to assembly <b>340</b>, where the conductive leads carry power and ground. Assembly <b>340</b> may be substantially made of plastic that is formed around these conductive leads. Assembly <b>340</b> may further include a metallic tab <b>342</b>, which may be coupled to, or an extension of, one of these conductive leads, for example, the conductive lead carrying ground. Metallic tab <b>342</b> may be in contact or close proximity to housing <b>310</b>. When housing <b>310</b> is metallic, this contact or close proximity can provide an electrical discharge path from housing <b>310</b> to ground. This can protect cable plug <b>305</b> from electrostatic discharge (ESD), for example, when housing <b>310</b> is touched by a user.

0042Contacts <b>330</b> and <b>332</b> may fit in passages in assembly <b>340</b>. Contacts <b>330</b> may provide power and ground terminals. For example, inside contacts <b>330</b> may provide a positive power supply while outside contacts <b>330</b> may provide ground. The passages may be formed at least partly by the conductive leads carrying power and ground, such that power and ground connections to the pins are formed when contacts <b>330</b> are inserted into passages in assembly <b>340</b>. Contacts <b>330</b> may be pogo pins or other types of pins. For example, they may be metallic pins inside of a conductive housing. A spring or other biasing mechanism may be located inside the housing, such that the pins remain in an extended state until cable plug <b>305</b> is mated with a compatible connector receptacle. When such mating takes place, the pins may be pushed back or retracted into housing <b>310</b>. Contact <b>332</b> may be a straight pin that is pushed into a detector circuit when cable plug <b>305</b> is mated with a compatible connector receptacle, though in other embodiments of the present invention, contact <b>332</b> may also be a pogo pin or other spring-biased contact.

0043Front plate <b>335</b> may be used to provide an attractive appearance when the contact portion of cable plug <b>305</b> is viewed. Front plate <b>335</b> may be plastic or other material and may be formed having a desirable color. For example, the color may match a color of cable <b>350</b>, housing <b>310</b>, or other component.

0044Attraction plate <b>325</b> can be magnetically attracted to magnets in a compatible connector receptacle. For example, magnetic field lines may originate in a first magnet in the compatible connector receptacle, pass through attraction plate <b>325</b>, and terminate in a second magnet in the compatible connector receptacle. Attraction plate <b>325</b> can be formed using a ferromagnetic metal or other material. In other embodiments of the present invention, attraction plate <b>325</b> may be formed using one or more magnets.

0045Dust cover <b>320</b> may cover attraction plate <b>325</b> during transport of the cable assembly or during other times when cable plug <b>305</b> is not inserted in a compatible connector receptacle, providing an improved appearance to cable plug <b>305</b>. Dust cover <b>320</b> may be metal, plastic, ceramic, or other material. For example, dust cover <b>320</b> may be formed of a transparent plastic. Dust cover <b>320</b> may also reduce or prevent dust or other particulate matter from entering housing <b>310</b> through gaps between housing <b>310</b> and attraction plate <b>325</b>. To help users avoid losing dust cover <b>320</b>, dust cover <b>320</b> may be attached to the cable assembly using a cord, tie, wire, or other fixture.

0046Circuit board <b>360</b> may fit around assembly <b>340</b>. Circuit board <b>360</b> may be a printed circuit board, flexible circuit board, or other appropriate circuit board. Circuit board <b>360</b> may include detection circuitry that may be triggered by contact detect pin <b>332</b>. Contacts <b>330</b> and <b>332</b> may be soldered to circuit board <b>360</b>. Circuit board <b>360</b> may be glued or otherwise fixed to assembly <b>340</b>.

0047LEDs <b>365</b> may be located on circuit board <b>360</b>. LEDs <b>365</b> may light when contact detect pin <b>332</b> is pushed, thereby indicating that cable plug <b>305</b> has been mated with a compatible connector receptacle.

0048Light pipes <b>370</b> may guide light from LEDs <b>365</b>. Light pipes <b>370</b> may be made of a transparent material. Light pipes may be colored to give interesting or informative coloring to light emitted by LEDs <b>365</b>. Light pipes <b>370</b> may be fixed to the inside of housing <b>310</b>.

0049Light insulators <b>380</b> may be used to prevent stray light from illuminating exits <b>312</b>. For example, light between plug portion <b>320</b> and housing <b>310</b> may otherwise illuminate exit <b>312</b>, thereby falsely indicating an electrical connection between cable plug <b>305</b> and a compatible connector receptacle. Light insulators <b>380</b> may be formed using foam or other opaque material. Light insulators <b>380</b> may be fixed to light pipes <b>370</b>, housing <b>310</b>, circuit board <b>360</b>, LEDs <b>365</b>, or other appropriate location.

0050In a specific embodiment of the present invention, during assembly, cable <b>350</b> may be inserted through housing <b>310</b> such that cable <b>350</b> emerges from the opening in housing <b>310</b> used by contacts <b>330</b>. Strain relief <b>315</b> and crimping ring <b>355</b> may be applied to cable <b>350</b>. A center conductor and metallic braiding of cable <b>350</b> may be soldered to contacts <b>345</b>. Contacts <b>330</b> and <b>332</b> may be fit in passages in assembly <b>340</b>. Circuit board <b>350</b>, including LEDs <b>365</b>, may be soldered to contacts <b>330</b> and <b>332</b> and affixed to assembly <b>340</b>. Front plate <b>335</b> and attraction plate <b>325</b> may be attached. This assembly may then fit through the opening in housing <b>310</b> as cable <b>350</b> is pulled away from housing <b>310</b>. The extent to which cable <b>350</b> is pulled may be determined by a manufacturing fixture. To facilitate the passage of strain relief <b>315</b> through housing <b>310</b>, glue may be used. This glue may provide lubrication as strain relief <b>315</b> passes through housing <b>310</b>. The glue may further act as an adhesive when dry to fix strain relief <b>315</b> and cable <b>350</b> in place relative to housing <b>310</b>. Dust cover <b>320</b> may be placed over attraction plate <b>325</b> and contacts <b>330</b> and <b>332</b>.

0051In another embodiment of the present invention, one or more of front plate <b>335</b> and attraction plate <b>325</b> are attached after assembly <b>340</b> and its connected components are fit through the opening in housing <b>310</b>. Cable <b>350</b> may be inserted through housing <b>310</b> such that cable <b>350</b> emerges from the opening in housing <b>310</b> used by contacts <b>330</b>. Strain relief <b>315</b> and crimping ring <b>355</b> may be applied to cable <b>350</b>. A center conductor and metallic braiding of cable <b>350</b> may be soldered to contacts <b>345</b>. Contacts <b>330</b> and <b>332</b> may be fit in assembly <b>340</b>. Circuit board <b>350</b>, including LEDs <b>365</b>, may be soldered to contacts <b>330</b> and <b>332</b> and affixed to assembly <b>340</b>. Front plate <b>335</b> may be attached at this point, or it may be attached later with attraction plate <b>325</b>. Alternately, front plate <b>335</b> and attraction plate <b>325</b> may be attached at this point, or they may be attached later. This assembly may then fit through the opening in housing <b>310</b> as cable <b>350</b> is pulled away from housing <b>310</b>. The extent to which cable <b>350</b> is pulled may be determined by a manufacturing fixture. To facilitate the passage of strain relief <b>315</b> through housing <b>310</b>, glue may be used. This glue may provide lubrication as strain relief <b>315</b> passes through housing <b>310</b>. The glue may further act as an adhesive when dry to fix strain relief <b>315</b> and cable <b>350</b> in place relative to housing <b>310</b>. Attraction plate <b>325</b> and front plate <b>335</b> may be attached at this time, as needed. Dust cover <b>320</b> may be placed over attraction plate <b>325</b> and contacts <b>330</b> and <b>332</b>.

0052In another embodiment of the present invention, during assembly, the cable and connected components are fit into the end of housing <b>310</b>. Strain relief <b>315</b> and crimping ring <b>355</b> may be applied to cable <b>350</b>. A center conductor and metallic braiding of cable <b>350</b> may be soldered to contacts <b>345</b>. Contacts <b>330</b> and <b>332</b> may be fit in assembly <b>340</b>. Circuit board <b>350</b>, including LEDs <b>365</b>, may be soldered to contacts <b>330</b> and <b>332</b> and affixed to assembly <b>340</b>. Contacts <b>330</b> and <b>332</b> may be retracted, and assembly <b>340</b> and its connected components fit into the end of housing <b>310</b>. Front plate <b>335</b> and attraction plate <b>325</b> may be attached before or after insertion. Again, glue may be used as a lubricant when strain relief <b>315</b> is inserted into housing <b>310</b>. Dust cover <b>320</b> may be placed over attraction plate <b>325</b> and contacts <b>330</b> and <b>332</b>.

0053Again, during assembly, light pipes <b>370</b> may be fixed to housing <b>310</b>. Light insulators <b>380</b> may be included to reduce the amount of stray light emitted from exits <b>312</b>. An example of this structure is shown in the following figure.

0054<figref idrefs="DRAWINGS">FIG. 4</figref> illustrates a side view of a portion of a cable plug <b>405</b> according to an embodiment of the present invention. Cable plug <b>405</b> may include housing <b>410</b> having openings or exits <b>412</b>. Light from LEDs <b>465</b> may be emitted through exits <b>412</b> when cable plug <b>405</b> is mated with a compatible connector receptacle (not shown.) Specifically, light from LED <b>465</b> may be guided by LED housing <b>467</b> towards light pipe <b>470</b>. Light pipe <b>470</b> may guide the light through opening or exit <b>412</b>. Light insulators <b>480</b> can prevent stray light inside the connector housing <b>410</b> from being emitted through exit <b>412</b>. For example, light may seep between housing <b>410</b> and attraction plate <b>420</b>, thereby appearing to falsely indicate that a connection has been made between cable plug <b>405</b> and a compatible connector receptacle.

0055It may be desirable to place a second light pipe in exit <b>412</b>. If this is done, it is further desirable that the second light pipe be flush with the surface of housing <b>410</b>, such that any ridges or bumps between the second light pipe and housing <b>410</b> are reduced or eliminated.

0056Accordingly, in a specific embodiment of the present invention, an adhesive is used to form a second light pipe in exit <b>412</b> of housing <b>410</b>. The adhesive may be placed in exit <b>412</b>. This adhesive may be light curing. Light may be applied to the inside of housing <b>410</b> to cure the adhesive. An air flow may be similarly applied to the inside of housing <b>410</b>, thereby pushing the adhesive out exit <b>412</b> as it is cured. Excess adhesive can then be wiped from the outside of housing <b>410</b>, such that the surface of the adhesive is flush with the outside of housing <b>410</b>. Light pipes <b>470</b> may be attached to these second light pipes formed by the adhesive.

0057Again, it is desirable to use halogen-free materials in manufacturing the cabling used in these power cable assemblies. Halogen is commonly used since it provides a flexible cable that is fire-resistant. Unfortunately, materials that are used for halogen-free cabling are themselves not fire retardant. Further, the addition of fire-retardant chemicals makes halogen-free cables brittle and is therefore not suitable. Accordingly, various embodiments of the present invention provide a strain relief that provides fire protection and is halogen-free. An example is shown in the following figure.

0058<figref idrefs="DRAWINGS">FIG. 5</figref> illustrates portions of a strain relief <b>500</b> according to an embodiment of the present invention. Strain relief <b>500</b> includes interior portion <b>510</b> and exterior portion <b>520</b>. Cabling <b>516</b> passes through interior portion <b>510</b>. Interior portion <b>510</b> can be formed or molded of a single piece of material. This material may be a hard plastic, such as a polycarbonate, polycarbonate ABS blend, or other appropriate material. This may provide fire protection, protecting an electronic device that is being charged.

0059Outer portion <b>520</b> of strain relief <b>500</b> may be formed in an additional molding step. This type of molding may be referred to as a double-shot process. Cable <b>526</b> passes through exterior portion <b>520</b>. Exterior portion <b>520</b> may be formed around a projection or key <b>512</b> of interior portion <b>510</b>, to provide a secure fit between interior portion <b>510</b> and exterior portion <b>520</b>. Key <b>512</b> may have protrusions such that exterior portion <b>520</b> does not rotate relative to interior portion <b>510</b>. Exterior portion <b>520</b> may be made of a flexible material, such as a thermoplastic elastomer, fluorinated ethylene propylene, or other appropriate material. Exterior portion <b>520</b> may provide the flexibility needed to protect cable <b>526</b> from excessive wear at its interface with strain relief <b>500</b> and the housing.

0060Interior portion <b>520</b> may be located in a housing. This housing may enclose a power transformer or converter, wired or wireless data or communication circuitry, or other types of electronics circuitry. The color of exterior portion <b>520</b> may be made to match a color of the housing or cable.

0061In other embodiments of the present invention, strain relief <b>500</b> may be formed using a three step process. In these embodiments, the additional step is a first molding step where cables <b>526</b> and <b>516</b> are covered. The following two steps provide the remainder of interior portion <b>510</b> and exterior portion <b>520</b>. In various embodiments of the present invention, cables <b>526</b> and <b>516</b> may be one cable or they may be multiple cables.

0062<figref idrefs="DRAWINGS">FIG. 6</figref> illustrates a strain relief <b>600</b> according to an embodiment of the present invention. Strain relief <b>600</b> includes interior portion <b>610</b> and exterior portion <b>620</b>. Interior portion <b>610</b> may provide fire protection, while exterior portion <b>620</b> may provide a flexible strain relief. A side of a housing, shown here by dashed lines, may fit in the gap or slot <b>628</b>. Again, the housing may house transformers, data communications circuitry, and other types of electronic circuitry.

0063The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.