The subject matter herein relates generally to electrical connectors having electrical contacts that engage corresponding mating contacts of another electrical connector.
Electrical connectors are used to transmit data and/or power in various industries. The electrical connectors are often configured to repeatedly engage and disengage complementary electrical connectors. The process of mating the electrical connectors may be referred to as a mating operation. For example, in a backplane communication system, a backplane circuit board has a header connector that is configured to mate with a receptacle connector. The receptacle connector is typically mounted to a daughter card. The header connector includes an array of electrical contacts (hereinafter referred to as “header contacts”), and the receptacle connector includes a complementary array of electrical contacts (hereinafter referred to as “receptacle contacts”). During the mating operation, the receptacle contacts mechanically engage and slide along the corresponding header contacts. The sliding engagement between the receptacle and header contacts may be referred to as wiping, because each receptacle contact wipes along an exterior surface of the corresponding header contact.
Electrical contacts are often plated to enhance performance and/or durability of the electrical contact. For example, electrical contacts used to transmit data signals may include one or more underlying contact materials and a layer of gold plating that covers the underlying contact material(s). Gold plating is generally inert and does not react with the surrounding environment. Consequently, the gold plating can protect the underlying material(s) of the electrical contact. Gold plating, however, may include pores that form during the plating process. The pores may expose the underlying material(s) to corrosive agents and may negatively affect electrical performance. To address these problems, the gold plating is often coated with a corrosion prevention compound, which is hereinafter referred to as a pore-blocking substance. The pore-blocking substance may include organic materials (e.g., non-metallic materials) and may impede or inhibit the development of corrosion through the pores.
The pore-blocking substance, however, may be inadvertently removed from the electrical contacts during the manufacture of the electrical connectors and/or during operation of the electrical connectors. For example, the sheet metal from which the electrical contacts are formed may be coupled to an interleaving paper that separates adjacent coiled layers of the sheet metal when the sheet metal is rolled. When the interleaving paper is removed, the pore-blocking substance may be removed with the paper. Also, when the electrical connectors are assembled, the pore-blocking substance may be removed when the electrical contacts engage portions of the connector housing or other objects. Furthermore, the pore-blocking substance may be removed during a mating operation between electrical connectors and/or evaporate during operation of the electrical connectors. When the amount of the pore-blocking substance is reduced, the electrical contacts may be more susceptible to damage.
Accordingly, a need remains for electrical contacts that maintain a sufficient amount of pore-blocking substance along an exterior surface of the electrical contacts.
In an embodiment, an electrical connector is provided that includes a connector housing that is configured to engage a mating connector during a mating operation. The electrical connector also includes a plurality of electrical contacts that coupled to the connector housing. Each of the electrical contacts includes a proximal base that is coupled to the connector housing and an elongated body that extends from the proximal base to a distal end. The elongated body has a body side that extends between the proximal base and the distal end and is configured to engage a corresponding mating contact of the mating connector. The body side has an indentation, wherein each of the electrical contacts includes a pore-blocking substance within the corresponding indentation.
In some aspects, the body side includes a sidewall that partially defines the indentation, and a contact area that is configured to directly engage the mating contact. The sidewall and the contact area are joined by a transition area of the body side that is shaped to permit wicking of the pore-blocking substance from the indentation to the contact area.
In some aspects, the body side is defined between opposite side edges and includes a contact area that extends between one of the side edges and the indentation. The body side is shaped such that the mating contact engages the contact area and extends at least partially over the indentation. In certain aspects, the body side has a centerline that extends between the side edges. The centerline may extend through the indentation.
In some aspects, the mating contact is configured to engage the body side at a contact zone that includes the indentation. The contact zone may include first and second contact areas that are located on opposite sides of the indentation. The first and second contact areas may coincide with a common plane.
In an embodiment, a communication system is provided that includes a receptacle connector having a plurality of receptacle contacts and a header connector having a plurality of header contacts. The header contacts are configured to engage corresponding receptacle contacts of the receptacle connector during a mating operation between the receptacle and header connectors. Each of the header contacts includes a proximal base and an elongated body that extends from the proximal base to a distal end. The elongated body has a body side that extends between the proximal base and the distal end and is configured to engage a corresponding receptacle contact of the receptacle connector. The body side has an indentation, wherein each of the header contacts includes a pore-blocking substance within the corresponding indentation.
In some aspects, the body side is defined between opposite side edges of the corresponding header contact and includes a contact area that extends between one of the side edges and the indentation. The corresponding receptacle contact may engage the contact area and extend at least partially over the indentation when the receptacle and header connectors are fully mated. Optionally, the receptacle contacts may wipe along the body sides of the corresponding header contacts as the receptacle and header connectors are mated.
In an embodiment, an electrical contact includes a proximal base that is configured to couple to a connector housing and an elongated body that extends from the proximal base to a distal end. The elongated body has a body side that extends between the proximal base and the distal end and is configured to engage a corresponding mating contact. The body side has an indentation, wherein each of the electrical contacts includes a pore-blocking substance within the corresponding indentation.
Embodiments set forth herein may include electrical contacts, electrical connectors having the electrical contacts, and communication systems having the electrical connectors. Embodiments include electrical contacts that may be configured to hold or retain a greater amount of a pore-blocking substance along an exterior surface of the electrical contact. Although the illustrated embodiment includes electrical connectors that are used in high-speed communication systems, such as backplane or midplane communication systems, it should be understood that embodiments may be used in other communication systems or in other systems/devices that utilize electrical contacts. Accordingly, the inventive subject matter is not limited to the illustrated embodiment.
In order to distinguish similar elements in the detailed description and claims, various labels may be used. For example, an electrical connector may be referred to as a header connector, a receptacle connector, or a mating connector. Electrical contacts may be referred to as header contacts, receptacle contacts, or mating contacts. When similar elements are labeled differently (e.g., receptacle contacts and mating contacts), the different labels do not necessarily require structural differences. For instance, in some embodiments, the receptacle contacts described herein may be referred to as mating contacts.
As used herein, the phrase “a plurality of electrical contacts” when used in the detailed description or the claims does not necessarily refer to each and every electrical contact of an electrical connector. For example, a contact array may include a first plurality of electrical contacts and a second plurality of electrical contacts. The first plurality may have certain features, such as indentations, that the second plurality does not have.
The circuit board assembly 102 includes a circuit board 110 having a first board side 112 and second board side 114. In some embodiments, the circuit board 110 may be a backplane circuit board, a midplane circuit board, or a motherboard. The circuit board assembly 102 includes a first header connector 116 mounted to and extending from the first board side 112 of the circuit board 110. The circuit board assembly 102 also includes a second header connector 118 mounted to and extending from the second board side 114 of the circuit board 110. The first and second header connectors 116, 118 include connector housings 117, 119, respectively. The first and second header connectors 116, 118 also include corresponding electrical contacts 120 that are electrically connected to one another through the circuit board 110. The electrical contacts 120 are hereinafter referred to as header contacts 120.
The circuit board assembly 102 includes a plurality of signal paths therethrough defined by the header contacts 120 and conductive vias 170 (shown in
The first and second header connectors 116, 118 include ground shields or contacts 122 that provide electrical shielding around corresponding header contacts 120. In an exemplary embodiment, the header contacts 120 are arranged in signal pairs 121 and are configured to convey differential signals. Each of the ground shields 122 may peripherally surround a corresponding signal pair 121. As shown, the ground shields 122 are C-shaped or U-shaped and cover the corresponding signal pair 121 along three sides.
The connector housings 117, 119 couple to and hold the header contacts 120 and the ground shields 122 in designated positions relative to each other. The connector housings 117, 119 may be manufactured from a dielectric material, such as a plastic material. Each of the connector housings 117, 119 includes a mounting wall 126 that is configured to be mounted to the circuit board 110 and shroud walls 128 that extend from the mounting wall 126. The shroud walls 128 cover portions of the header contacts 120 and the ground shields 122.
The first connector system 104 includes a first circuit board 130 and a first receptacle connector 132 that is mounted to the first circuit board 130. The first receptacle connector 132 is configured to be coupled to the first header connector 116 of the circuit board assembly 102 during a mating operation. The first receptacle connector 132 has a mating interface 134 that is configured to be mated with the first header connector 116. The first receptacle connector 132 has a board interface 136 configured to be mated with the first circuit board 130. In an exemplary embodiment, the board interface 136 is oriented perpendicular to the mating interface 134. When the first receptacle connector 132 is coupled to the first header connector 116, the first circuit board 130 is oriented perpendicular to the circuit board 110.
The first receptacle connector 132 includes a front housing or shroud 138. The front housing 138 is configured to hold a plurality of contact modules 140 side-by-side. As shown, the contact modules 140 are held in a stacked configuration generally parallel to one another. In some embodiments, the contact modules 140 hold a plurality of electrical contacts 142 (shown in
The second connector system 106 includes a second circuit board 150 and a second receptacle connector 152 coupled to the second circuit board 150. The second receptacle connector 152 is configured to be coupled to the second header connector 118 during a mating operation. The second receptacle connector 152 has a mating interface 154 configured to be mated with the second header connector 118. The second receptacle connector 152 has a board interface 156 configured to be mated with the second circuit board 150. In an exemplary embodiment, the board interface 156 is oriented perpendicular to the mating interface 154. When the second receptacle connector 152 is coupled to the second header connector 118, the second circuit board 150 is oriented perpendicular to the circuit board 110.
Similar to the first receptacle connector 132, the second receptacle connector 152 includes a front housing 158 used to hold a plurality of contact modules 160. The contact modules 160 are held in a stacked configuration generally parallel to one another. The contact modules 160 hold a plurality of receptacle contacts (not shown) that are electrically connected to the second circuit board 150. The receptacle contacts are configured to be electrically connected to the header contacts 120 of the second header connector 118. The receptacle contacts of the contact modules 160 may be similar or identical to the receptacle contacts 142 (
In the illustrated embodiment, the first circuit board 130 is oriented generally horizontally. The contact modules 140 of the first receptacle connector 132 are oriented generally vertically. The second circuit board 150 is oriented generally vertically. The contact modules 160 of the second receptacle connector 152 are oriented generally horizontally. As such, the first connector system 104 and the second connector system 106 may have an orthogonal orientation with respect to one another.
Although not shown, in some embodiments, the communication system 100 may include a loading mechanism. The loading mechanism may include, for example, latches or levers that fully mate the corresponding receptacle and header connectors. For instance, the loading mechanism may be operably coupled to the receptacle connector 132 and, when actuated, drive the receptacle connector 132 into the header connector 116 to assure that the receptacle and header connectors 132, 116 are fully mated.
The conductive vias 170 extend into the circuit board 110. In an exemplary embodiment, the conductive vias 170 extend entirely through the circuit board 110 between the first and second board sides 112, 114. In other embodiments, the conductive vias 170 extend only partially through the circuit board 110. The conductive vias 170 are configured to receive the header contacts 120 of the first and second header connectors 116, 118. For example, the header contacts 120 include compliant pins 172 that are configured to be loaded into corresponding conductive vias 170. The compliant pins 172 mechanically engage and electrically couple to the conductive vias 170. Likewise, at least some of the conductive vias 170 are configured to receive compliant pins 174 of the ground shields 122. The compliant pins 174 mechanically engage and electrically couple to the conductive vias 170. The conductive vias 170 that receive the ground shields 122 may surround the pair of conductive vias 170 that receive the corresponding pair of header contacts 120.
The ground shields 122 are C-shaped and provide shielding on three sides of the signal pair 121. The ground shields 122 have a plurality of walls, such as three planar walls 176, 178, 180. The planar walls 176, 178, 180 may be integrally formed or alternatively, may be separate pieces. The compliant pins 174 extend from each of the planar walls 176, 178, 180 to electrically connect the planar walls 176, 178, 180 to the circuit board 110. The planar wall 178 defines a center wall or top wall of the ground shield 122. The planar walls 176, 180 define side walls that extend from the planar wall 178. The planar walls 176, 180 may be generally perpendicular with respect to the planar wall 178. In alternative embodiments, other configurations or shapes for the ground shields 122 are possible in alternative embodiments. For example, more or fewer walls may be provided in alternative embodiments. The walls may be bent or angled rather than being planar. In other embodiments, the ground shields 122 may provide shielding for individual header contacts 120 or sets of contacts having more than two header contacts 120.
The contact modules 140 are coupled to the front housing 138 such that the receptacle contacts 142 are received in corresponding contact openings 200. Optionally, a single receptacle contact 142 may be received in each contact opening 200. The contact openings 200 may be configured to receive corresponding header contacts 120 (
The front housing 138 may be manufactured from a dielectric material, such as a plastic material, and may provide isolation between the contact openings 200 and the contact openings 202. The front housing 138 may isolate the receptacle contacts 142 and the header contacts 120 from the ground shields 122. In some embodiments, the contact module 140 includes a conductive holder 210. The conductive holder 210 may include a first holder member 212 a second holder member 214 that are coupled together. The holder members 214, 214 may be fabricated from a conductive material. As such, the holder members 214, 214 may provide electrical shielding for the first receptacle connector 132. When the holder members 214, 214 are coupled together, the holder members 214, 214 define at least a portion of a shielding structure.
The conductive holder 210 is configured to support a frame assembly 220 that includes a pair of dielectric frames 230, 232. The dielectric frames 230, 232 are configured to surround signal conductors (not shown) that are electrically coupled to or include the receptacle contacts 142. Each signal conductor may also be electrically coupled to or may include a mounting contact 238. The mounting contacts 238 are configured to mechanically engage and electrically couple to conductive vias 262 of the first circuit board 130. Each of the receptacle contacts 142 may be electrically coupled to a corresponding mounting contact 238 through the signal conductor (not shown).
In the illustrated embodiment, the receptacle contacts 142 are identical. As such, the following description is applicable to each of the receptacle contacts 142. It should be understood, however, that the receptacle contacts 142 of the signal pair 141 are not required to be identical. It should also be understood that the receptacle contacts 142 of the corresponding receptacle connector are not required to be identical. For example, in some embodiments, the receptacle contacts may be configured differently so that the receptacle contacts electrically engage the corresponding header contacts at different times during the mating operation.
Each of the contact fingers 302, 304 includes a base portion 306, a beam portion 308, and a joint portion 310. The beam portions 308 extend to respective mating interfaces 312, which are defined between opposite edge portions 470, 472. The mating interfaces 312 of the contact fingers 302, 304 face each other with a contact-receiving gap 314 therebetween. In the illustrated embodiment, the corresponding mating interfaces 312 of the contact fingers 302, 304 are substantially paddle-shaped or tab-shaped. The mating interface 312 includes a flared portion 313 that extends away from the opposing mating interface 312 to enlarge the contact-receiving gap 314. The curved contour of the mating interfaces 312 and the flared portions 313 may facilitate receiving one of the header contacts 120 (
In
When the contact fingers 302, 304 are in deflected conditions, each of the contact fingers 302, 304 may generate a normal force that presses the corresponding mating interface 312 against the corresponding header contact 120 in a direction toward the other mating interface 312. As such, the contact fingers 302, 304 may pinch the corresponding header contact 120 therebetween. To this end, each of the contact fingers 302, 304 may be configured to provide a designated normal force when the corresponding contact finger is in a deflected condition. For example, the base portion 306 may have a designated length 316, the beam portion 308 may have a designated length 318, and the joint portion 310 may have a designated shape or contour. Each of the contact fingers 302, 304 may also have a designated thickness 319. In an exemplary embodiment, the thickness 319 is substantially uniform throughout the corresponding contact finger. The lengths 316, 318, the shape of the joint portion 310, and the thickness 319 may be configured such that each of the contact fingers 302, 304 provides a designated normal force against the header contact 120. The lengths 316, 318 and the shape of the joint portion 310 may also be configured to locate the mating interface 312 at a designated location along the header contact 120 (
The header contact 120 may include a contact tail 182 that has the compliant pin 172. The header contact 120 also includes a proximal base 410 that couples to the contact tail 182, and an elongated body 412 that extends from the proximal base 410 to the distal end 402. The contact tail 182 includes the board end 404, and the elongated body 412 includes the distal end 402. As described above, the compliant pin 172 mechanically engages and electrically couples to a corresponding conductive via 170 (
In the illustrated embodiment, the header contact 120 has a linear structure from the board end 404 to the distal end 402. In other embodiments, however, the header contact 120 may not be linear from the board end 404 to the distal end 402. For example, the elongated body 412 may be linear and extend along the longitudinal axis between the distal end 402 and the proximal base 410 as shown in
In the illustrated embodiment, the elongated body 412 includes body sides 421, 422, 423, 424 that extend generally along the longitudinal axis 406 between the proximal base 410 and the distal end 402. The body sides 421-424 may be exposed within the housing cavity 164 (
The body side 421 is configured to engage a corresponding contact finger, such as one of the contact fingers 302, 304 (
The wipe track 428 includes a contact zone 432 that represents an area along the body side 421 that is configured to engage the contact finger after the corresponding receptacle and header connectors are fully mated. More specifically, the contact zone 432 may represent the area that includes the operating position (or final resting position) of the mating interface 312 (
Also shown, the body side 421 includes an indentation 434 that is located within or proximate to the contact zone 432. The indentation 434 is a portion of the exterior surface 426 that is recessed or depressed with respect to the surrounding portion of the exterior surface 426. The indentation 434 is configured to retain or store a pore-blocking substance 436 (shown in
Although the above description was with respect to the body side 421, the body side 423 may have similar features. In an exemplary embodiment, the body sides 421, 423 have identical configurations. For example, if the header contact 120 were rotated 180° about the longitudinal axis 406, the elongated body 412 would have the same appearance as shown in
In an exemplary embodiment, the header contact 120 is stamped (or coined) from sheet metal having opposite side surfaces with a thickness extending therebetween. When the header contact 120 is stamped, the body sides 421, 423 may be formed from the opposite side surfaces of the sheet metal, and the body sides 422, 424 may be edges formed by the stamping process. The stamping process may also provide the indentations 434. Alternatively, the indentation 434 may be formed before or after the stamping process that provides the body sides 421-424. The elongated body 412 may have a substantially uniform body thickness 458 that is measured between the first and second body sides 421, 423, and a body width 460 that is measured between the body sides 422, 424. In an exemplary embodiment, the thickness 458 and the body width 460 are substantially equal. However, the body width 460 and the thickness 458 may not be equal in other embodiments.
After stamping an unfinished header contact 120 from the sheet metal, the header contact 120 may be treated to include one or more designated coatings. By way of example, the sheet metal may include a copper alloy. After stamping a base material from the sheet metal, a first coating (not shown) may be applied directly to the base material (e.g., the stamped copper alloy). A second coating (not shown) may be applied onto the first coating. The first and second coatings may be applied using, for example, an electroplating process. In an exemplary embodiment, the first coating includes nickel or tin and functions as a diffusion barrier between the base material and the second coating. The second coating may include gold. In an exemplary embodiment, the gold is plated from the distal end 402 to a location beyond the contact zone 432. Optionally, the gold may be selectively located at the contact zone 432 and not between the distal end 402 and the contact zone 432.
After the second coating is applied, the pore-blocking substance 436 (
With respect to
When the contact finger 304 directly engages one or both of the contact areas 444, 446, an electrical connection between the contact finger 304 and the header contact 120 is established. The body side 421 and the contact finger 304 are dimensioned relative to each other such that the contact finger 304 directly engages at least one of the contact areas 444, 446 and the contact finger 304 extends laterally over at least a portion of the indentation 434. In the illustrated embodiment, the contact finger 304 extends laterally over the entire indentation 434 and engages each of the contact areas 444, 446. In other embodiments, however, the contact finger 304 may extend laterally over only a portion of the indentation 434 and/or engage only one of the contact areas 444, 446.
In particular embodiments, the indentation 434 is centrally located along the body side 421. For example, the centerline 429 may represent a line that extends along the elongated body 412 and intersects midpoints between the side edges 440, 442. The centerline 429 may extend through the indentation 434. In the illustrated embodiment, the centerline 429 extends through a center of the indentation 434.
Also shown in
The contact finger 304 also has a width 464 that may be measured transverse to the longitudinal axis 406 when the contact finger 304 is in the operating position. In the illustrated embodiment, the width 464 of the contact finger 304 is greater than the width 462 of the indentation 434. For example, the width 464 may be at least about 1.5 times (1.5×), at least about 2.0 times (2×), or at least about 2.5 times (2.5×) the width 464 of the indentation 434.
With respect to
It is understood that tolerances during the manufacture and assembly of the communication system 100 (
At stage 471, the indentation 434 holds a designated volume of the pore-blocking substance 436. As shown, the indentation 434 may be partially defined by an interior sidewall 473 that includes a transition area 474 and a bottom portion 475. The transition area 474 extends between the contact area 446 and the bottom portion 475 of the sidewall 473. The interior sidewall 473 may be part of the exterior surface 426. For example, the interior sidewall 473 and the contact area 446 may be part of a common side surface of the sheet metal prior to the stamping process. The interior sidewall 473 may be formed by the stamping process.
In some embodiments, the transition area 474 is shaped to permit wicking of the pore-blocking substance 436 from the indentation 434 to the contact area 446. The transition area 474 may be substantially smooth such that wicking is facilitated along the transition area 474. For example, the transition area 474 may have a substantially curved contour relative to the bottom portion 475. The bottom portion 475 may be more planar than the transition area 474 and/or may be substantially perpendicular to the plane 450 (
Stages 471 and 472 illustrate the wicking action that may occur in some embodiments. At stage 471, the pore-blocking substance 436 forms a fill line 476 within the indentation 434 that is substantially flush with the contact area 446. At stage 472, a portion of the pore-blocking substance 436 has moved from the indentation 434 to the contact area 446 causing the fill line 476 to lower. Without being held to a particular theory or mechanism, it is believed that the pore-blocking substance 436 may move from the indentation 434 to the contact area 446 because of inherent properties of the pore-blocking substance 436 and a surface energy of the exterior surface 426 and/or the contact finger 304. More specifically, the pore-blocking substance 436 may have cohesive forces that draw the pore-blocking substance 436 to itself and may have adhesive forces with respect to the contact area 446 and a surface of the contact finger 304. As such, the pore-blocking substance 436 may be drawn from the indentation 434 and onto the contact area 446. The wicking action may be similar to capillary action. Accordingly, embodiments set forth herein may be capable of retaining a sufficient amount of the pore-blocking substance 436 along the contact area 446, which may reduce the likelihood of corrosion developing along the header contact 120 (
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
As used in the description, the phrase “in an exemplary embodiment” and the like means that the described embodiment is just one example. The phrase is not intended to limit the inventive subject matter to that embodiment. Other embodiments of the inventive subject matter may not include the recited feature or structure. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
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Number | Date | Country | |
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20160006166 A1 | Jan 2016 | US |