This invention relates generally to electrical connectors, and, more particularly, to separable electrical connectors operable under energized electrical load current conditions.
In certain installations, such as interconnection of lighting ballasts for fluorescent lights, it is desirable to connect or disconnect lighting ballasts in an energized electrical system. Ballasts may therefore be connected or disconnected to the electrical system by plugging and unplugging electrical connectors without having to de-energize or shut down some or all of the electrical system. Thus, with convenient plug connectors, a lighting system may be safely and more easily replaced when lighting requirements change. Thus, for example, lighting ballasts may be added or removed to an existing lighting system with plug-in connection. Connecting and breaking load currents in such a system, however, presents a number of challenges.
For example, making and breaking of the electrical connection under load conditions may result in intense energy discharges within the connector system as the connector contacts are engaged and disengaged. For example, known lighting systems may operate at voltages of 277 V to 600 V, and may experience currents of 1-5 A in normal operation Most commercially available connectors are not suited for completing and breaking such connections under load. In particular, energy discharge as electrical connections are completed and broken in such load conditions may damage the electrical contacts of the connectors and prevent them from being properly engaged or disengaged. Especially when such connectors are repeatedly used to connect or disconnect the electrical connection, damage to the electrical contacts is a primary concern.
Additionally, electricians, maintenance personnel or homeowners using the connector system must be protected from the energy associated with completing and breaking an energized electrical connection. Electricians, maintenance personnel or homeowners must also be protected from inadvertent contact with energized portions of the connector assembly in an unplugged condition.
Most commercially known connectors are incapable of providing safe and reliable connection and disconnection under energized circuit conditions while meeting other considerations such as ease of wire termination and low cost.
In an exemplary embodiment, an electrical contact is provided. The contact includes a contact body having an axial length, a termination section extending from the body, a primary contact area extending from the body and spaced from the body by a first axial length, and a sacrificial leading contact beam extending from the body for a second axial length. The second length is greater than the first length, and a distal end of the contact beam is configured to complete or break an energized electrical connection with a mating contact.
In another embodiment, a connector assembly comprises a first connector comprising a housing and a first contact therein, and a second connector matable with the first connector. The second connector includes a housing and a second contact therein. The first contact comprises a wire termination section, a primary contact area spaced from the wire termination section, and a leading contact beam spaced from the primary contact area. The second contact establishes electrical connection with the leading contact beam before establishing electrical connection with the primary contact area when the connectors are mated. In one embodiment, the wire termination section is a poke-in contact section.
In yet another embodiment, a connector assembly comprises a first connector comprising a housing and a first contact therein. The first contact includes a wire termination section, a pair of primary contact beams and a leading contact beam configured to complete and break an energized electrical connection. A second connector is matable with the first connector in plugged and unplugged positions. The second connector comprises a housing and a second contact having a contact blade therein. When the first and second connectors are mated, the contact blade establishes electrical connection with the leading contact beam at an end thereof and at a location spaced from the pair of primary contact beams before being received by and establishing electrical connection with the pair of primary contact beams.
As explained below, the connector assembly 100 permits connection of the load wires 106, 107 and the line wires 108, 109 that requires minimal time and effort to complete. Moreover, the connectors may be engaged and disengaged to reliably complete and break electrical interconnection of the wires 106, 107 and 108, 109 while the wires are energized and still under electrical load. That is, the connector assembly 100 is operable without de-energizing the associated circuitry, sometimes referred to herein as “hot plugging.”
The contacts 112 are formed from a sheet of conductive material according to, for example, a known stamping and formation process. In an exemplary embodiment, the contacts 112 each include a contact blade 126 at one end, and a compliant contact section having a compliant contact beam 128 at a second end thereof that receives the respective wire stripped ends 120, 122 with poke-in connection in the illustrated embodiment. Deflectable latch tabs 130 are also provided in the contacts 112 that cooperate with locking protrusions or locking apertures in the housing receptacle 116 to secure and maintain the contacts 112 in a predetermined position within the housing 110. When the contacts 112 are loaded into the housing 110, the contact blades 126 are located within the contact receptacle 116 of the housing 110 as seen in
An end 152 of the housing 140 opposite the leading portion 144 is generally closed or solid with two apertures (not shown) that receive stripped ends 154, 156 of the respective line wires 108, 109. A locking element 158 is formed on a surface of the housing main body 146 adjacent the leading portion 144. The locking element 158 receives the latch beam 124 (
The primary contact beams 160 in each contact 142 extend obliquely from the contact body 161 and toward one another for a predetermined length, and distal ends 168 of the contact beams 160 are outwardly flared from one another. The leading contact beams also extend 162 also extend from the contact body 161, and more specifically extend axially and forwardly beyond the distal ends 168 of the primary contact beams 160 for a specified distance. Distal ends 168 of the leading contact beams 162 are rounded or raised at a location spaced from the distal ends 168 of the primary contact beams 160. When the contacts 142 are loaded into the housing 140, the distal ends 168 of the leading contact beams 162 are located within the respective contact receptacles 148, 150 of the housing leading portion 144 and are recessed or spaced from the distal end of the housing and the open end of the receptacles 148, 150. As such, the energized line contacts 142 are generally recessed within the housing 140 to prevent inadvertent operator contact with the energized contacts 142 when the male and female connectors are unplugged or disengaged.
In use, as the male connector 102 and the female connector are engaged or plugged, the distal ends 168 of the leading contact beams 162 establish electrical contact with the contact blades 126 (
As the connectors 102, 104 continue to be engaged and moved toward one another, the contact blades 126 of the male connector 102 engage the distal ends 168 of the primary contact beams 160 until the primary contact beams 160 are deflected and the contact blades 126 are received between each respective pair of primary contact beams 160 in the female connector 104. The primary contact beams 160 define a contact area for engagement with the contact blades 126 apart from contact areas associated with the leading contact beam distal ends 168. The deflection of the primary contact beams 160 generates a normal force on the surface of the contact blades 126 to ensure mechanical and electrical engagement of the primary contact beams 160 and the contact blades 126 at a location unaffected by any damage to the leading edge of the contact blades 126, and a primary current path or contact area is established therebetween.
Likewise, as the male connector 102 and the female connector 104 are moved apart from one another to disengage or unplug the connector assembly 100, the contact blades .126 of the male connector 102 break electrical contact with the primary contact beams 160 before electrical contact is broken with distal ends 168 of the leading contact beams 162 in the female connector 104. Thus, energy associated with disengagement of the contacts 112, 142 under load is discharged at the interface of the contact blades 126 and the leading contact beam distal ends 168 at a location away from the primary contact beams 160. Accordingly, any residual damage that may occur from repeated plugging and unplugging of the male and female connectors 102, 104 under energized circuit conditions is experienced at the leading edge of the contact blades 126 and the distal ends 168 of the leading contact beams 162. In such a manner, the sacrificial leading contact beams 162 dissipate most of the energy and incur potential damage when the connectors 102, 104 are engaged and disengaged under load, while the primary contact beams 160 are protected for safe and reliable operation of the connectors 102, 104.
As is also shown in
The assembly 200 includes the female connector 104 and the male connector 102 substantially as described above, except that the male connector 102 includes contacts having right angle legs 202 so that the male connector 102 may be mounted to a circuit board 204 with known through-hole mounting techniques. The right angle legs 202 may be formed with the aforementioned contacts 112 via known stamping and formation techniques, and as shown in
It is appreciated that the connector assembly 300 can include contact legs with different configurations or designs to assure cable to board connection via the connector assembly 300. Alternatively, the male and female connectors 304 may be modified to connect, for example, first and second cables including respective line and load wires instead of interconnecting a cable and a circuit board.
The contacts 312 are formed from a sheet of conductive material according to, for example, a known stamping and formation process. In an exemplary embodiment, the contacts 312 each include a contact blade 326 at one end, and the right angle legs 307 at an opposite end. The contacts 312 may be fitted in the second end 318 of the housing 310 with, for example, a force fit or interference fit. When the contacts 312 are loaded into the housing 310, the contact blades 326 are located within the contact receptacle 316 of the housing 310, and distal ends of the contact blades 326 are recessed or spaced from the housing first end 114. The contact legs 307 may be mounted to, for example, a circuit board.
The leading portion 344 defines first and second contact receptacles 348, 350 and is of a slightly smaller outer dimension than the main body 346. Retaining features may be provided in the contact cavities 348, 350 and/or within the main body 346 to secure the contacts 342 within the receptacles 348, 350 and/or the main body 346.
An end 352 of the housing 340 opposite the leading portion 344 includes hinged covers 354, 356 that each include a generally closed or solid rear wall 358 with an aperture 360 therein that receives a stripped end of the respective line wires 306, 308 when the contacts 342 are loaded in the housing main body 346.
Referring to
A distal end of the channel portion beam 366 includes a sacrificial leading contact region having a rounded edge 372 projecting upwardly from the channel portion beam 366. Compliant contact sections including compliant beams 374 are formed in the contacts 342 opposite the leading portion 362, and the contact beams 374 receive and retain the respective a wire stripped ends 376 with, for example poke-in connection. Other known wire termination methods and techniques, however, may alternatively be employed in other embodiments.
The primary contact beams 364 in each contact 342 extend axially and parallel to one another for predetermined length, and a distal end of the channel portion beam 366 extends axially and forwardly beyond the distal ends of the primary contact beams 364 for a specified distance. When the contacts 342 are loaded into the housing 340 (
In use, as the male connector 302 and the female connector 304 are engaged or plugged, the distal ends of the contact channel portion beams 366 establish electrical contact with the contact blades 326 (
As the connectors continue to be engaged and moved toward one another, the contact blades 326 engage the distal ends of the primary contact beams 364 until the primary contact beams 364 are deflected and the contact blades 326 are received in the slot 368. The deflection of the primary contact beams 364 generates a normal force on the surface of the contact blades 326 to ensure mechanical and electrical engagement of the primary contact beams 364 and the contact blades 326 at a location unaffected by any damage to the leading edge of the contact blades 326, and a primary current path is established therebetween. In such an embodiment, the side of the contact blade 326 that engages with the channel portion beam 366 is a sacrificial region, and the other side or surface of the blade 326 establishes primary contact with the beams 364 at a location unaffected by any damage or debris from the plugging and unplugging of the connectors 302 and 304.
Likewise, as the male connector 302 and the female connector 304 are moved apart from one another to disengage or unplug the connector assembly 300, the contact blades 326 break electrical contact with the primary contact beams 364 before electrical contact is broken with distal ends of the leading contact channel portion beams 366. Thus, energy is discharged at the interface of the contact blades 326 and the leading contact channel portion beams 366 at a location away from the primary contact beams 364, and any residual damage that may occur from repeated plugging and unplugging of the male and female connectors 302, 304 under energized circuit conditions is experienced at the leading edge of the contact blades 326 and the distal ends of the leading contact channel portion beams 362.
As also shown in
The several embodiments of connector assemblies described herein are provided for illustrative purposes only to illustrate the inventive concepts, and it is understood that the inventive concepts could be extended to other types and configurations of electrical contacts and connectors. For example, hermaphroditic or self mating contacts and housings could be provided with sacrificial contact regions for dissipating energy and incurring damage from plugging and unplugging energized electrical connections as described above. Further, the connector housings could include hermaphroditic engagement surfaces and/or polarizing or keying features to further enhance the touch safe connector systems described above for hot plugging operation. For example,
The male connector 400 including a housing 402 fabricated from a nonconductive or dielectric material, and contacts 404 loadable into the housing 402. The housing 402 is generally cylindrical in an exemplary embodiment, but includes recessed cutout sections 406 giving the housing 402 the general outline of a figure eight on an open first end 408. While the housing 402 is illustrated with one particular shape, it is appreciated that other geometric shapes of the housing 402 may likewise be used in alternative embodiments.
The open first end 408 defines a contact cavity or receptacle 410 that receives the contacts 404. Retaining features may be provided in the contact cavity 410 to secure the contacts 402 within the receptacle 410. The housing 402 includes a generally closed second end 412 opposite the first end 410, and the second end 412 includes two apertures (not shown) that receive load wires 414, 416. A latch element 418 is provided for mating engagement with a latch feature of a mating connector.
The contacts 404 are inverted relative to one another within the housing 402 as shown in
Referring to
When the contacts 404 are loaded into the housing 402, the contact blades 430 are located within the contact receptacle 410 of the housing 402, and distal ends 440 of the contact blades 430 are recessed or spaced from the housing first end 408. The contacts 404 are inverted or loaded into the housing 402 so that the contact beams 436 face in opposite directions as best shown in
The leading portion 458 defines first and second contact receptacles 464, 466 and is of a slightly smaller outer dimension than the main body 460. Retaining features may be provided in the contact cavities 464, 466 and/or within the main body 458 to secure the contacts 454 within the receptacles 464, 466 and/or the main body 460. An end 468 of the housing 452 opposite the leading portion 458 includes is generally closed with respective apertures therein that receive stripped ends of respective line wires 470, 472 when the contacts 454 are loaded in the housing main body 460.
The contacts 454 are inverted relative to one another within the housing 452 as shown in
Referring to
When the contacts 454 are loaded into the housing 452, the leading edges 430 are located within the contact receptacles 464 and 466, and distal ends 490 of the leading edges 490 are recessed or spaced from the open edge of the receptacles 464 and 466. The contacts 454 are inverted or loaded into the housing 452 so that the primary contact beams 486 face in opposite directions as best shown in
The leading edge 480 of each contact 454 is forked and defines a slot 492 that is dimensioned to accept the contact blade 430 (
As the connectors 400, 450 continue to be engaged, the tapered side edges of the contact blades 430 engage and deflect the distal ends 488 of the primary contact beam 486, thereby establishing another contact area or point of electrical contact with the contact blades 430 at a location spaced from the sacrificial contact regions 494 and unaffected by dissipation of energy as the connectors 400, 450 are mated. Furthermore, deflection of the primary contact beams 486 generates normal force contact between the contact beam 488 and the respective tapered side edge of the contact blade 430. Because the contacts 454 are inverted in the female housing 452, the primary contact beams 486 are deflected in opposite directions when the connectors are mated. Also, in an exemplary embodiment, the contact beams 436 (
When the connectors 400, 450 are unplugged or disengaged from one another, the tapered side edges of the contact blades 430 disengage from the distal ends 488 of the primary contact beams 486 before the sacrificial regions 494 disengage the contact blades 430. Consequently, the sacrificial contact regions 494 dissipate most of the energy when the male and female connectors 400, 450 are unplugged under electrical load conditions, and incur any incidental or residual damage from repeated hot plugging at a location away from the primary contact beams 486.
As shown in
The leading edge 502 of the contact 500 is forked and defines a slot 508 that is dimensioned to accept the contact blade 430 (
Consequently, the sacrificial contact regions 510 establish electrical contact with the male contact blade 430 before the primary contact regions 514 establish electrical connection with the contact blade 430 when the male and female connectors are engaged. Consequently, the sacrificial contact regions 510 dissipate most of the energy when the male and female connectors are plugged under electrical load conditions, and incur any incidental or residual damage from repeated hot plugging.
As the connectors continue to be engaged, the contact blade 430 establishes electrical connection with the primary contact regions 514, thereby establishing another point of electrical contact with the contact blades 430 at a location spaced from the sacrificial contact regions 510 and unaffected by dissipation of energy as the connectors are mated.
Likewise, when the connectors are unplugged or disengaged from one another, the contact blade 430 disengages from the primary contact regions 514 before the sacrificial regions 510 disengage the contact blade 430. Consequently, the sacrificial contact regions 510 dissipate most of the energy when the male and female connectors are unplugged under electrical load conditions, and incur any incidental or residual damage from repeated hot plugging at a location away from the primary contact regions 514.
Each contact 530a, 530b includes a contact body 536, a leading contact beam 538 extending from the body 536, and a primary contact beam 540 formed with and extending from the body 536. Termination sections 541 also extend from the contact bodies 536, and in an exemplary embodiment the termination sections 541 include compliant contact beams 542 that receive and retain respective line and load wires with poke-in connection. In an exemplary embodiment, the contacts 530 are reversed and inverted with respect to one another in the respective housings 526a, 526b. That is, for each pair of mating contacts 530a, 530b in the respective housings 526a, 526b, the termination sections 541 face in opposite directions along a longitudinal axis of the connector housings 526, 528, and the primary contact beams 540 face in opposite directions extending transversely to the longitudinal axis.
Distal ends of the contact beams 540 are spaced from the contact body 536 by an axial length that is less than the spacing of the distal ends of the leading contact beams 538 from the contact bodies 536. Consequently, when the connectors 522, 524 are mated with one another, distal ends of the leading contact beams 538 of the respective contacts 530a, 530b establish electrical connection with one another before establishing electrical connection with the primary contact beams 540. The leading contact beams 538 accordingly define a sacrificial contact area that dissipates most of the energy associated with mating of the contact under load and incurs and residual damage from repeated hot plugging of the connectors. The leading contact beams 538 slidably engage one another as the connectors 522, 524 are mated.
As the connectors 522, 524 continue to be mated, the primary contact beams 540 or each contact 530a, 530b mechanically and electrically engages the leading contact beam 538 of the other contact 530a, 530b. As such, the primary contact beams 540 define a primary contact area that mechanically and electrically engages the respective leading contact beams 538 of the mating contacts. The primary contact beams 540 establish such electrical connection at a location spaced from the sacrificial contact area of the leading contact beams 538 and substantially unaffected by dissipation of energy as the connectors are plugged under electrical load. When fully engaged, and as shown in
When the connectors 522, 524 are unplugged, the primary contact beams 540 disengage the leading contact beam 538 of the mating contact before the leading contact beams 538 disengage from one another. Thus dissipation of energy as the energized electrical connection is broken is dissipated in the sacrificial areas of the leading contact beams 538 and not at the primary contact areas of the primary contact beams 540. Reliable hot plugging and unplugging is therefore ensured. Like the foregoing embodiments, the connectors 522, 524 are touch safe in each of the plugged and positions to protect electricians, maintenance personnel or homeowners from electric shock or hazard during hot plugging and unplugging.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.