Connector with arc inhibiting construction

Abstract

The present invention relates to an electrical connector, comprising a connector body, a plug contact carried by the connector body and having a free end adapted to be received in a cavity of a mating socket contact, the plug contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than the first material, and wherein the coating covers the free end of the plug contact. The present invention also relates to a plug contact for an electrical connector.

Description

CONNECTOR WITH ARC INHIBITING CONSTRUCTIONTechnical Field

[0001] The present disclosure relates generally to electrical connectors including electrical connectors through which high electrical power is routed.Background

[0002] Electrical connectors are generally comprised of conductive elements known as contacts that carry electrical data, signals, or power, or any combinations of these electrical transmissions. When connectors are energized and under load as the connectors are coupled together, electricity can cross an air gap between adjacent contacts. This phenomenon is sometimes called "arcing" or electrical flashing and results in a less- contained and less-controlled transfer of energy between the connectors. Depending on the amount of energy within an arcing or electrical flashing event, damage to the connectors or associated components can result.Disclosure of the Invention

[0003] According to an aspect of the invention, an electrical connector is provided. The electrical connector comprises a connector body, a plug contact carried by the connector body and having a free end adapted to be received in a cavity of a mating socket contact, the plug contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than the first material, and wherein the coating covers the free end of the plug contact. The mating socket contact can be external to the plug contact.

[0004] According to another aspect of the invention, an electrical connector is provided. The electricalconnector comprises a connector body, a socket contact carried by the connector body and having an inlet end that defines an opening to a cavity in the socket contact, the socket contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than the first material, and the socket contact includes a contact portion that is spaced from the coated portion and in which the first material is exposed.

[0005] According to a further aspect of the invention, a plug contact for an electrical connector is provided. The plug contact may also be referred to as an electrical contact or electrical contact element. The plug contact having a free end adapted to be received in a cavity of a mating socket contact, the plug contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than the first material, and wherein the coating covers the free end of the plug contact. The mating socket contact can be external to the plug contact.

[0006] Other aspects and features are defined in the appended claims.

[0007] All aspects herein provided have in common to provide a solution that overcomes the shortcomings and limitations of the state of the art. Further, they have in common to inhibit or prevent arcing during connection or disconnection of the electrical connector pair, preferably under load or under voltage.

[0008] Examples of the disclosure may make it possible to obtain an electrical connector that provides an improved contact and durability between the two components in particular by reducing the friction. Other possible advantages will be apparent in the following detailed description.Brief Description of the Drawings

[0009] The following detailed description of preferred implementations and best mode will be set forth with regard to the accompanying drawings, in which:

[0010] FIG. 1 is a perspective view of an electrical connector pair including a first connector and a second connector;

[0011] FIG. 2a is a diagrammatic side view of a plug contact and a socket contact in a disconnected position;

[0012] FIG. 2b is a diagrammatic side view of the plug contact and the socket contact in a partially connected position;

[0013] FIG. 2c is a diagrammatic side view of the plug contact and the socket contact in a fully connected position;

[0014] FIGS. 3a and 3b are diagrammatic side views of a plug contact and a socket contact in a disconnected position and a fully connected position;

[0015] FIGS. 4a, 4b and 4c are diagrammatic side views of a plug contact and a socket contact in a disconnected position, a partially connected position and a fully connected position;

[0016] FIGS. 5a and 5b are diagrammatic side views of a plug contact and a socket contact in a disconnected position and a fully connected position;Detailed Description

[0017] In different applications, high power electrical energy is transmitted via or passed through electrical connectors, where power is a function of current and voltage (Power = current * voltage), involving either AC or DC current. A representative electrical connector pair 10 is shown in FIG. 1 and includes mating first and second connectors 12, 14. The first connector 12 includes a first connector body16 and multiple plug contacts 18 carried by the first connector body 16. The second connector 14 includes a second connector body 20 and multiple cavities 22 each having a socket contact 24 (labeled in FIG. 2a among other figures) carried by the second connector body 20. The first and second connector bodies 16, 20 are adapted to be physically coupled together with the plug contacts 18 at least partially received in a cavity 22 and contacting at least part of respective socket contacts 24. The physical contact or engagement between the plug contacts 18 and the socket contacts 24 provides an electrically conductive connection through which electricity may be transmitted. The first and second connector bodies 16, 20 may include multiple plug and / or socket contacts with each body having all plug contacts, all socket contacts, or a combination of both types of contacts, as desired. In at least some applications, the electrical power transmitted by these types of connectors may range up to 600 volts and up to 1,000 amps. Such connectors may be used in, by way of non-limiting examples, electrical generation stations or substations industrial automation and control, various machinery applications, and power distribution units for data centers.

[0018] The first and second connector bodies 16, 20 may be formed from an insulative material like rubber or plastic, and surround the area of the plug contact 18 to socket contact 24 engagement between the first and second connectors 12, 14. In the example shown, the first connector body 16 includes a cavity 26 surrounding the plug contacts 18 such that the plug contacts 18 are cantilevered to the first connector body 16 at a first end and extend to a free end 28 located in the cavity 26. The free end 28 of the plug contacts 18 may include the tip or axially outermost end of the plug contact, and, in at least some embodiments, a region extending axially less than half the axial dimension of the plug contact 18. In the example shown, the second connector body 20 includes an insert or plug fitting 30 in which the socket contacts 24 are received and supported.

[0019] When the first connector body 16 and second connector body 20 are connected together, the plug fitting 30 is at least partially received in the cavity 26 and the plug contacts 18 are at least partiallyreceived in aligned ones of the socket contacts 24. Each mated pair of plug contacts 18 and socket contacts24 provides an electrically conductive path through which electricity may be transmitted.

[0020] Connection and disconnection of the connector bodies generally occurs in three scenarios. These scenarios include when the connectors are: 1) not energized and are not under load; 2) energized but not under load; and 3) energized and under load. In this context, a contact is "energized" if there is a voltage or potential difference present on the contact as measured with respect to a circuit ground or earth ground. And a contact is under "load" if the contact is transmitting or carrying any significant or measurable amount of electrical current.

[0021] When the connectors 12, 14 are energized and under load, connection of the connectors can, when the mating contacts 18, 24 of the connectors are moved close to each other and prior to full connection, cause electricity to jump an air gap between adjacent contacts. This phenomenon is sometimes called "arcing" or electrical flashing and results in a less-contained and less-controlled transfer of energy between the connectors 12, 14. Depending on the amount of energy within an arcing or electrical flashing event, damage to the connectors or associated components can result.

[0022] FIGS. 2a-2c diagrammatically show a single plug contact 18 and a single socket contact 24 when disconnected (FIG. 2a), partially connected (FIG. 2b) and fully connected (FIG. 2c). The plug contact 18 that has a cylindrical body 32 with a center axis 34 and a free end 28 at least part of which may be of a reduced size. For example, the free end 28 may be rounded, such as with a partially spherical or similar shape, or with a conical or frustoconical shape, by way of non-limiting examples. The reduced size free end 28 may have a smaller cross-sectional area, taken perpendicular to the axis 34 along plane 36, than the remainder of the plug contact body 32. The reduced size free end 28 facilitates initial sliding receipt of the plug contact 18 within a corresponding socket contact 24, and accommodates slight misalignment of the contacts as the connector bodies are aligned and connected together. The reduced sized free end 28 mergesor blends with the adjacent portion of the cylindrical body 32 of the plug contact 18 which has a size selected to be closely received in and in contact with an inner surface 38 of the socket contact 24, as shown in FIGS. 2b and 2c.

[0023] In the example shown, the socket contact 24 has a cavity 40 with an open, inlet end 41 in which at least part of the plug contact 18 is received. The cavity 40 is defined by the inner surface 38 of the socket contact 24, which may be formed of metal or other electrically conductive material and which may have a central axis 42. The cavity 40 may be cylindrical, and have a diameter sized with respect to the diameter of the plug contact 18 for close receipt of the plug contact 18, with metal-to-metal contact between them. If desired, the cavity 40 may have other shapes and need not be a constant diameter cylinder. For example, the inner surface 38 defining the cavity 40 of the socket contact 24 may be wavy (e.g. like a sine wave) having portions with a smaller diameter than other portions with the smaller diameter portions arranged for metal-to-metal engagement with the plug contact body, or otherwise shaped as desired. An outer surface 43 of the socket contact 24 may be surrounded at least in part by material of the second connector body 20, as shown in FIG. 1 , to support the socket contact 24 and maintain its position and alignment relative to the second connector body 20.

[0024] In at least some implementations, to inhibit or prevent arcing during connection or disconnection of first and second connector bodies 16, 20 of an electrical connector pair 10, as shown in FIGS. 2a, 2b and 2c, a coating 44 is applied to part of the plug contacts 18. The coating 44 may be of a dielectric, electrically insulating, and / or thermally insulating material or composition. Representative, but nonlimiting materials for the coating include: air curable heat resistant polymer coatings, oven curable heat resistant polymer coatings, polymeric coatings with a high ceramic filler content to provide electrical insulation and heat resistance, coatings that are painted on, coatings that are vacuum deposited, coatings that are sputtered on, coatings that could involve a sol-gel process for the application of thin ceramic layers,coatings that involve functionally gradient materials that transition from metal to ceramic, coatings that involve diffusion between the coating and the base material, coatings that are applied by thermal spray technology. The coating may have one or more of: 1) a lower coefficient of friction (static or kinetic friction) than the material of the plug contact itself, to reduce friction between the plug contact and the socket contact; 2) a high hardness; 3) high abrasion resistance; 4) resistance to higher temperatures; and 5) good dielectric strength. For example, in at least some implementations, the coating may have one or more of a hardness and scratch resistance of at least 8H on the pencil hardness gage scale, temperature resistance up to 1800F, and dielectric strength up to 118 volts per micrometer. These attributes may reduce damage to the coating 44 during multiple connection and disconnection cycles of the connector bodies 16, 20, and improve the durability and useful life of the coating 44 and the contacts 18, 24, and may reduce wear and damage to the contacts during an arcing event. The coating 44 may be a ceramic or refractory material, such as but not limited to, silicon carbide, tungsten carbide and titanium carbide. The coating 44 may be polymeric or metallic. The material of the coating 44 may have a contact resistance below a threshold value, such as a resistivity of 200 E-08 ohm-meters or higher, and the material may be partially conductive, if desired. In at least some implementations, it may be desirable to limit the contact resistance, to, for example, not lower than 30 milli-ohms for the contact when the male coated pin is in contact with the uncoated female socket, for example.

[0025] The coating 44 may be applied in any desired manner. Non-limiting examples include electroplating, electroless plating, dip coating, spray coating, painting - mechanical, dip, spray, etc., vacuum vapor deposition, physical vapor deposition, chemical vapor deposition and electroarc or electrospark deposition. The coating 44 may cure in air, or require an elevated curing temperature to achieve a final form factor, and may involve chemical reaction, such as 2-part epoxies, or other reactive formulations.

[0026] In the implementation shown in FIGS. 2a-2c, the coating 44 is applied over the entirety of the free end 28 of the plug contact 18 and over part of the plug contact body 32 adjacent to the free end 28, but not the entire body 32. The coating 44 may be circumferentially continuous so that no portion of the underlying plug contact 18 is exposed within the coated portion of the plug contact 18. The axial length of the part of the plug contact 18 that includes the coating 44 is less than the total axial length of the plug contact 18 that is received in and overlapped by the socket contact 24. So arranged, when the plug contact 18 is fully inserted into the socket contact 24 (i.e. to the extent the plug contact is inserted when the connector bodies are in a fully connected position), as shown in FIG. 2c, an uncoated portion of the plug contact body 32 is received in the socket contact 24, and is engaged by the socket contact 24 to provide a conductive interface region 46 between the plug contact 18 and socket contact 24. In at least some implementations, the axial length of the coating 44 on the cylindrical body 32 of the plug contact 18, not including the reduced size free end 28, is 25% or less than the diameter of the plug contact 18.

[0027] In at least some implementations, the coating 44 has a thickness of between 0.0254 micrometers and 250 micrometers. This thin coating 44 does not materially degrade the physical contact between the exposed, uncoated portion 45 of the plug contact body 32 and the socket contact 24. In other words, direct, physical contact occurs between the uncoated portion 45 of the plug contact 18 and the socket contact 24, to enable a reliable conductive interface between them.

[0028] As shown in FIG. 2a, during a connection between first and second connector bodies 16, 20 (shown in FIG. 1), the plug contact 18 is aligned with the socket contact 24 as the connector bodies are slidably coupled. In FIG. 2b, the plug contact 18 is partially received in the cavity 40 of the socket contact 24 with the coated portion of the plug contact 18 nearly fully received in the cavity 40 as the first and second connector bodies are partially but not yet fully connected together. Prior to this position, the coating44 which covers the portion of the plug contact 18 that first engages the socket contact 24, has preventedor substantially inhibited electrical conduction between the plug contact 18 and the socket contact 24, and the distance from the socket contact 24 to the uncoated portion 45 of the plug contact 18 was too great for an arc to cross the air gap between them.

[0029] In the position shown in FIG. 2b, the uncoated portion 45 of the plug contact 18 is moved close enough to the socket contact 24 that an arc could develop between an inlet end 41 of the socket contact 24 and the axially leading part or edge 48 of the uncoated portion 45 of the plug contact 18, but such arcing, if any, would occur when the connector bodies 16, 20 are already partially connected, which may provide some physical barrier / containment of the arc and shielding from the exterior environment. Further, any such arcing would be lesser in magnitude due to the presence of the coating 44 and resulting local changes in equipotential lines of the electric field, and would occur during the sliding movement of the plug contact 18 and so would be shorter in duration as compared to an arc that could occur without any coating 44 and before a plug contact is inserted at all into a socket contact. In at least some implementations, the arc energy may be reduced by up to 90%. As shown in FIG. 2c, the once the uncoated portion 45 of the plug contact 18 is within the socket contact 24 and engaged (metal-to-metal contact) with the inner surface 38 of the socket contact 24, there is direct electrical conduction between the contacts 18, 24 and no arcing.

[0030] In the implementation shown in FIGS. 3a and 3b, the plug contact 18 may be constructed and arranged in the same manner described above with regard to FIGS. 2a-2c, including the coating 44. In this implementation, the socket contact 50 is different and may be shaped to provide a positive compressive force on a plug contact 18 inserted in the cavity 52 of the socket contact 50. In the implementation shown, the socket contact 50 may include flexible and resilient arms 54 that may be separated by slots 56 that extend through the free end 58 of the arms 54 which collectively define an inlet 60 (FIG. 3b) to the cavity 52. In this way, the material of the arms 54 that define the inlet 60 to the cavity 52 is not circumferentially continuous and instead includes multiple circumferentially spaced apart slots 56 between circumferentiallyadjacent arms 54.

[0031] The free end 58 of each arm 54 may be radially inwardly bent or inclined so that the free ends 58 define a minimum diameter or cross-sectional area of the cavity 52 at the inlet 60 to the cavity 52, where such area is taken perpendicular to a central axis 62 of the inlet 60 and cavity 52. Axially inward from the inlet 60, the cavity 52 may have a larger diameter or cross-sectional area. Further, the inlet 60 to the cavity 52 may have a surface area equal to or less than the outer diameter of the plug contact 18 so that one or more arms 54 are outwardly flexed when a plug contact 18 is received in the inlet 60 of the socket cavity 52, to ensure good physical contact / engagement between them.

[0032] The socket contact 24 may include any desired number of arms 54, and each arm 54 may have some degree of freedom from the other arms 54 to permit radially outward flexing of the arms 54. Further, the resilient or springy material of the arms 54 causes them to tend to return to their initial, unflexed position after the arms 54 are outwardly flexed. In this way, when a plug contact 18 is inserted into the cavity 52, the free ends 58 of the arms 54 engage the exterior of the plug contact 18 and the arms 54 may be radially outwardly flexed, and the resilient arms 54 then provide a compressive force on the exterior surface of the plug contact 18 in an area of engagement 64 (FIG. 3b) which defines a conductive interface region between the mated contacts 18, 50 which may comprise a limited axial extent of the arms 58 and the plug contact 18. This provides a good conductive interface between the contacts 18, 50 and ensures a predictable engagement and contact resistance over time, with repeated connections and disconnections of the connectors.

[0033] As noted earlier, the remainder of the cavity 52 axially spaced from the area of engagement 64 may be larger than the plug contact 18 providing a gap or open space 66 surrounding a corresponding portion of the plug contact 18, axially spaced from the area of engagement 64. In this way, a defined area of engagement 64 is provided which facilitates a connection with a desired contact resistance andconductivity between the contacts 18, 50. The portion of the socket contact 60 that defines the area of engagement 64 may be defined by the radially inner surface 68 of the free ends 58 of the arms 54, which may include a portion that extends axially from the absolute end 70 of the arms 45, and which is arranged to be parallel to the central axis 62 or within 5 degrees of parallel, when a plug contact 18 is inserted into the socket contact, taking into account flexing of the arms 54 that may occur.

[0034] In the implementation shown, the socket cavity 52 is defined in part by a bottom stop 72 that limits the extent to which the plug contact 18 can be inserted into the socket contact 50. When fully inserted, the engagement area 64 between the contacts 18, 50 is axially spaced from the coating 44 on the plug contact 18. And the bottom stop 72 facilitates consistent, full insertion of the plug contacts 18 to provide a consistent engagement area 64 between the contacts 18, 50 in use, where the socket contact 50 engages a location of the plug contacts 18 that is spaced from the coating 44 on the plug contact 18.

[0035] In use, when the first and second connectors 12, 14 are coupled together, the plug contact 18 is coaxially aligned with the inlet 60 to the cavity 52 of the socket contact 50, and as the plug contact 18 is axially advanced into the cavity 52, the plug contact 18 engages the free ends 58 of the arms 54 of the socket contact 50. The sliding engagement occurs initially between the coated portion of the plug contacts 18 and the free ends 58 of the arms 54, and the coating 44 prevents or substantially inhibits conduction between the contacts 18, 50. As the plug contact 18 is further moved into the socket contact cavity 52, the area of sliding engagement reaches the uncoated portion 45 of the plug contact 18.During insertion of the plug contact 18 into the socket contact 50, the interaction between the contacts may be generally as described above with regard to FIGS. 2a-2c, with a difference being in the more limited area of engagement 64 between the mated contacts 18, 50 due to the cavity 52 being larger than the plug contact 18 outboard of the area of engagement 64.

[0036] Another embodiment of a plug contact 80 and a socket contact 50 is shown in FIGS. 4a, 4band 4c. In this embodiment, the socket contact 50 may be the same as that described above with regard to FIGS. 3a and 3b, and the same reference numerals will be used to facilitate description and understanding of the embodiment of FIGS. 4a-4c. In this embodiment, plug contact 80 includes a coated portion 82 that includes multiple, spaced apart coated regions. Other than the coated portion 82, the plug contact 18 may be the same as previously described.

[0037] As shown, the plug contact 80 includes a first coated region 84 that includes the free end 86 of the plug contact 80. This first coated region 84 may be the same as that described above with regard to the coating 44 of plug contact 18. A second coated region 88 of the plug contact 80 is provided axially spaced from the first coated region 84. The second coated region 88 may be applied over a limited axial extent of the exterior of the plug contact 80, and may be spaced from the first coated region 84 by any desired axial distance. The second coated region 88 may be circumferentially continuous and a first edge 90 of the second coated region 88 may be parallel to the adjacent edge 92 of the first coated region 84, which may be arranged in a plane perpendicular to the central axis 94 of the plug contact 80. Of course, other angles and orientations of the coated regions and edges may be used, including by way of non-limiting examples, edges in plane that is not perpendicular to the central axis, edges that are wavy, zig-zagged or jagged, among others.

[0038] Additional coated regions may be provided on the plug contact 80, as desired. In the embodiment shown, the plug contact 81 includes a third coated region 96 that is axially spaced from the second contact region 88, and a fourth contact region 98 that is axially spaced from the third contact region 96. Between the coated regions 84, 88, 96, 98, the exterior surface of the plug contact 80 may be exposed which provides alternation conductive and insulating regions along the axial length of the plug contact 80, extending from the free end 86 to a desired axial extent or location along the body of the plug contact 80.The third and fourth coated regions 96, 98 may be constructed and arranged like the second contact region88 or in any other way. In the example shown, each of the second, third and fourth contact regions 88, 96. 98 are cylindrical and are evenly spaced from each other, and it is noted that the spacing between adjacent coated regions need not be equal.

[0039] In use, as the plug contact 80 is slidably inserted into the socket contact 50, there are multiple regions of insulating and conducting material of the plug contact 80 that alternatively come into sliding contact with the socket contact 50, in the area of engagement 64, as best shown in FIG. 4b. In at least some implementations, the coated regions 84, 88, 96, 98 have an axial dimension that is less than the axial dimension of the area of engagement 64 between the plug contact 80 and socket contact 50, that is, less than the axial dimension of the portion of the socket contact 50 that is engaged the plug contact 80. Thus, when the plug contact 80 slidably engages the socket contact 50 in the area of the second, third or fourth coated regions 88, 96, 98, there are multiple conductive pathways between the contacts 50, 80, separated by at least one coated region. The multiple conductive pathways allow current to be distributed on at least two conducting regions, and thereby potentially providing at least two different arc initiation sites to potentially lower the arc current density at any one site. This may limit damage to the contacts 50, 80 and other components, and may better preserve the final area of engagement between the contacts, shown in FIG. 4c. In at least some implementations, the axial dimension of at least one coated region is such that the coated region ends an axial distance that is between 1 / 3 and 1 / 4 of the diameter of the plug contact 18 away from at least a portion of an area of conduction, e.g. the arear of engagement 64, between the contacts when the connectors are coupled together.

[0040] In another embodiment of connectors having mating plug and socket contacts, as shown in FIGS. 5a and 5b, portions of the socket contact 100 can include a coated portion 101 having a coating 102. In at least some implementations, the plug contact also includes one or more coated portions, such as those shown on the plug contact 18 of FIGS. 2a-2c, and on plug contact 80 of FIGS. 4a-4c. In the example shown,the plug contact is constructed and arranged like the plug contact 18 and so the same reference numerals will be used to facilitate description of this embodiment. In at least some implementations, including the embodiment shown in FIGS. 5 a and 5b, the socket contact 100, other than the coating 102, may be constructed and arranged like the socket contact 50 with arms 54 and free ends 58, and so the same reference numerals will be used to facilitate description of this embodiment.

[0041] As shown in the socket contact 100 of FIGS. 5a and 5b, the coating 102 may be provided on portions of the socket contact 100 outside of the portion of the arms 54 that are intended to engage the plug contact 18 and define the area of engagement 64. The coating 102 may be provided over part of the radially inner surfaces 68 of the arms 54, the radially outer surface 104 of the arms, the axial tip or axially outermost surface of the free end 58 of the arms, and the bottom stop 72. When the connectors are fully coupled, the plug contact 18 is received in the socket contact cavity 52 and the inner surfaces of the arms 54 engage the exterior surface of the plug contact 18 in the area of engagement 64. The rest of the plug contact 18 that is received within the cavity 52 may include a coating or be surrounded by portions of the coating on the socket contact, in at least some implementations.

[0042] The coating 102 on the socket contact 100 may be of the same material as the coating on the plug contacts 18, 80, if desired, or a different material. The thickness of the coating 102 on the socket contact 100 may be same as that of the plug contact 18, or the thickness of the coating 102 may be greater than the thickness of the coating on the plug contact 18, 80. At least with a socket contact cavity 52 that is larger in cross-sectional area than the plug contact 18, some or all of the space between the plug contact 18 and the material of the socket contact 50, 100 can be filled by the coating 102, if desired. In this way, a majority of the plug contact 18 may include or be surrounded by a coating, with a defined area of engagement 64 provided via which electrical conduction occurs between the contacts.

[0043] Among other things, providing a coating on selected portions of one or both contacts 18, 50,80, 100 can limit regions on the electrical contacts where arcing can physically occur, allow contacts to be repeatedly cycled through connection and disconnection cycles while minimizing the damage that could occur from arcing, enhance the ability of electrical contacts to meet specific requirements from a wide range of certification bodies in terms of their ability to withstand a certain number of connection and disconnection cycles, minimize or reduce insertion force with a coating having a lower coefficient of friction while maintaining an adequate contact / engagement force between the contacts when the connectors are coupled together, provide thermally and / or electrically insulated regions that can be in specific locations or patterns providing desired conductive and insulative regions, reduce generation of wear-related debris and prevent the formation of more severe forms of arcing due to the presence of metal debris or arc interactions with other particulate in the area of mating contacts, and protect the region of final contact, i.e., the region of engagement between contacts when the connectors are fully coupled together, where the majority of the electrical current flows so that this engagement region maintains a low contact resistance, even if other regions of the electrical contact may experience arc-related degradation.

[0044] The coating may be somewhat thin to maintain a desired size of connectors and not require a significantly larger connector to achieve the desired insulation or contact protection. Further, the coating may remain on the contact(s) for repeated connection and disconnection cycles without significant degradation to provide lasting benefits to the contact(s). That is, in at least some implementations, the coating is not consumed if arcing occurs and the coating is intended to remain on the contact over repeated connection and disconnection cycles.

[0045] At least some embodiments utilize spatially distributed coatings of dielectric or electrically insulating and / or thermally insulating material applied to the surfaces of one or both of a mating pair of electrical contacts. The spatial location and configuration of the coatings can be optimized so that upon thecontacts being joined / connected together to come into good electrical contact, the region where the conductive electrical contact is eventually made is controlled as is the area(s) where electrical conduction is precluded or substantially inhibited. Optimization can be achieved with regard to actions resulting in both connection and disconnection of the connectors and associated contacts. For example, the spatial configuration and pattern of the coating can be selected to limit and control regions of good electrical contact and thereby limit regions where potential arcing could occur during connection of the connectors. Also or instead, the spatial configuration and pattern of the coating can be selected to limit electrical arcing in both the region of good electrical contact as well as elsewhere on the electrical contact.

[0046] Further, the coatings can also reduce friction between the contacts as they are connected and disconnected. Coatings with favorable tribological properties can reduce the frictional forces needed to connect or disconnect the pair of electrical contacts. In at least some applications, relatively high normal contact forces are needed to get a low electrical contact resistance in the region of the physical contact between the plug and socket contacts that is still in good electrical contact and does not contain the insulative coatings. However, high normal forces could translate to high frictional forces, depending on the static and dynamic coefficients of friction, assuming that the frictional behavior of the electrical contacts during connection and disconnection could be modeled by a Coulombic friction constitutive relationship.

[0047] Still further, the coatings can improve the durability of the contacts and enable the contacts to function over a suitable number of connection and disconnection cycles when energized and under load. In many applications for high power, such as industrial automation and control, machinery, power distribution units for data centers, and many other applications requiring the delivery of high power and thereby causing conditions of energized electrical load, there can be specific technical requirements concerning the number of connection and disconnection cycles over which a specific electrical contact needs to be capable of remaining operational. The specific performance metrics associated with suchtechnical specifications could include contact resistance and temperature rise after the electrical contacts experience a threshold number of cycles of connection and disconnection under electrical load. Examples of such specifications are formulated by outside third-party testing laboratories or standards organizations such as, but not limited to, UL, CE, IEE, IEEE, SAE, FAA, FDA, ASTM, and the like.

[0048] While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.

[0049] All terms used in the claims are intended to be given their broadest reasonable construction and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as "a," "the," "said," etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

Claims

CLAIMS1. An electrical connector, comprising: a connector body; a plug contact carried by the connector body and having a free end adapted to be received in a cavity of a mating socket contact, the plug contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than the first material, and wherein the coating covers the free end of the plug contact.

2. The connector of claim 1 wherein the plug contact has a central axis and the coating extends from the free end along part of the axial dimension of the plug contact, and wherein the plug contact has a contact region that is axially spaced from the coated portion.

3. The connector of claim 2 wherein the coating is continuous and the first material is entirely covered by the coating within the coated portion.

4. The connector of claim 2 wherein the contact region has an axial dimension that is greater than the axial dimension of the coated portion.

5. The connector of claim 1 wherein the free end includes a portion with a reduced cross-sectional area taken perpendicular to a central axis of the plug contact, and wherein the coating covers the portion with the reduced cross-sectional area.

6. The connector of claim 1 wherein the coated portion includes a first coated region and a second coated region spaced from the first coated region.

7. The connector of claim 6 wherein the first coated region includes an axial end of the plug contact and the first material is exposed between the first coated region and the second coated region.

8. The connector of claim 1 wherein the coated portion includes multiple coated regions with each of the multiple coated regions spaced from other ones of the multiple coated regions so that the first material is exposed between adjacent ones of the multiple coated regions.

9. The connector of claim 1 wherein the first material is metal and the second material is polymeric, ceramic or a metal different from that of the first material.

10. The connector of claim 1 wherein the second material is dielectric.

11. The connector of claim 1 wherein the coating has a thickness of between 0.025 micrometers and 250 micrometers.

12. The connector of claim 1 wherein the second material is one or more of: more thermally insulative than the first material; of a material having a lower coefficient of sliding friction compared to the first material; or of a material having greater hardness than the first material.

13. An electrical connector, comprising: a connector body; a socket contact carried by the connector body and having an inlet end that defines an opening to a cavity in the socket contact, the socket contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than thefirst material, and the socket contact includes a contact portion that is spaced from the coated portion and in which the first material is exposed.

14. The connector of claim 13 wherein the cavity is defined by an inner surface of the socket contact and wherein the coating is applied to part of the inner surface that does not include the contact portion.

15. The connector of claim 14 wherein the socket contact includes multiple slots that define multiple arms between the slots, each of the multiple arms having a free end that defines part of the inlet cavity.

16. The connector of claim 15 wherein the coated portion includes the axial end of each free end.

17. A plug contact for an electrical connector, having a free end adapted to be received in a cavity of a mating socket contact, the plug contact is formed from a first material and has a coated portion that includes a coating that is formed from a second material that is less electrically conductive than the first material, and wherein the coating covers the free end of the plug contact.

18. The plug contact of claim 17 wherein the coating is continuous and the first material is entirely covered by the coating within the coated portion.

19. The plug contact of claim 18 wherein the contact region has an axial dimension that is greater than the axial dimension of the coated portion.

20. The plug contact of claim 17 wherein the free end includes a portion with a reduced cross-sectional area taken perpendicular to a central axis of the plug contact, and wherein the coating covers the portion with the reduced cross-sectional area.

21. The plug contact of claim 17 wherein the coated portion includes a first coated region and a second coated region spaced from the first coated region.

22. The plug contact of claim 21 wherein the first coated region includes an axial end of the plug contact and the first material is exposed between the first coated region and the second coated region.

23. The plug contact of claim 17 wherein the coated portion includes multiple coated regions with each of the multiple coated regions spaced from other ones of the multiple coated regions so that the first material is exposed between adjacent ones of the multiple coated regions.

24. The plug contact of claim 17 wherein the first material is metal and the second material is polymeric, ceramic or a metal different from that of the first material.

25. The plug contact of claim 17 wherein the second material is dielectric.

26. The plug contact of claim 17 wherein the coating has a thickness of between 0.025 micrometers and 250 micrometers.

27. The plug contact of claim 17 wherein the second material is one or more of: more thermally insulative than the first material; of a material having a lower coefficient of sliding friction compared to the first material; or of a material having greater hardness than the first material.

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