Information
-
Patent Grant
-
6764349
-
Patent Number
6,764,349
-
Date Filed
Friday, March 29, 200222 years ago
-
Date Issued
Tuesday, July 20, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Ta; Tho D.
- Tuskerman; Larisa
Agents
- Hwang; David H.
- Teradyne Legal Dept.
-
CPC
-
US Classifications
Field of Search
US
- 439 701
- 439 74
- 439 608
- 439 609
- 439 947
-
International Classifications
-
Abstract
An electrical connector system suitable for use in a matrix assembly. The electrical connector assembly has two connectors, each assembled from wafers. Certain of the connectors include a combination of signal and power conductors while others have only signal conductors. In this way, the signal density is maximized.
Description
This invention relates generally to electronic assemblies and more specifically to electrical connectors for routing signals between printed circuit boards in an electronic assembly.
Electronic systems are often assembled from several printed circuit boards. These circuit cards are sometimes referred to as “daughter boards.” The daughter boards are held in a card cage. Electrical connections are then made between the daughter boards.
One traditional approach is to interconnect the daughter cards using a backplane. The backplane is a large printed circuit board with few, if any, active components attached to it. Mainly, the backplane contains signal traces that route electrical signals from one daughter card to another. It is mounted at the back of the card cage assembly and the daughter cards are inserted from the front of the card cage. The daughter cards are in parallel to each other and at right angles to the backplane.
For ease of assembly, the daughter cards are connected to the backplane through a separable connector. Often, two-piece electrical connectors are used to join the daughter cards to the backplane. One piece of the connector is mounted to each of the backplane and a daughter card. These pieces mate and establish many conducting paths. Sometimes, guide pins are attached to the backplane that guide the daughter board connector into proper alignment with the backplane connector.
A two piece electrical connector has contacts in each piece of the connector that are adapted to make electrical contact when the two pieces mate. A traditional backplane connector has contacts that are shaped as pins or blades and the daughter card contact has contacts that are shaped as receptacles. Each pin is inserted into a receptacle when the connectors mate.
To make a high speed, high density connector, shielding is often added to the connectors. U.S. Pat. No. 5,993,259 to Stokoe, et al. represents a desirable shielding design and is hereby incorporated by reference. Teradyne, Inc., the assignee of that patent markets a connector called VHDM® that is commercially successful. Interconnection systems often employ power connectors along with signal connectors. In this way, power is transmitted from the backplane to the daughter cards to power the circuitry on the daughter cards. U.S. patent application Ser. No. 09/769,867 entitled “Waferized Power Connector” filed Jan. 25, 2001 by Cohen et al., (which is hereby incorporated by reference) describes a waferized power connector that is suitable for use in an assembly with signal connectors. Teradyne, Inc., the assignee of that patent markets a connector called GbX™ that is commercially successful.
Not all electronic assemblies employ a backplane. Some use a midplane configuration. In a midplane configuration, daughter cards are inserted into both the front and the back of the card rack. Another printed circuit board, called the midplane, is mounted in the center of the card cage assembly. The midplane is very similar to a backplane, but it has connectors on both sides to connect to the daughter boards inserted from the front and the back of the assembly.
A further variation is called a matrix configuration. In the matrix configuration, daughter boards are inserted from both the front and the back of the card cage. However, the boards inserted from the front are perpendicular to the boards inserted from the back. Connectors are mounted at the interconnection of these circuit boards to make connections between the boards.
Currently, there exists no suitable high speed, high density connectors for some matrix configurations. And, there exists no such connector system for a matrix configuration that readily incorporates power connectors.
SUMMARY OF THE INVENTION
With the foregoing background in mind, it is an object of the invention to provide power contacts for a connection system in a matrix configuration.
It is also an object to provide a matrix connector that is easy to manufacture.
The foregoing and other objects are achieved in a connector with two intermateable pieces. Each piece is made from a plurality of subassemblies, with some adapted to provide power connections. In the preferred embodiment, each piece includes both signal and power contacts.
In a preferred embodiment, each connector piece includes both power contacts and signal contacts oriented to provide a generally square component, allowing connector pieces attached to boards oriented orthogonal to each other to mate.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood by reference to the following more detailed description and accompanying drawings in which
FIG. 1
is a illustration of a matrix assembly according to the invention;
FIG. 2
is an exploded view of a first type connector of
FIG. 1
;
FIG. 3
is an exploded view of a second type connector of
FIG. 1
;
FIGS. 4A-4D
is a series of figures showing steps in the manufacturing process of a wafer of
FIG. 2
;
FIG. 5
is an illustration of a preferred embodiment of a compliant section;
FIGS. 6A and 6B
are illustrations showing additional details of features on the shield of
FIG. 4C
;
FIGS. 7A and 7B
are sketches showing additional detail of the compliant attachment of the preferred embodiment;
FIGS. 8A and 8B
are sketches showing additional details of the wafer of
FIG. 3
;
FIG. 9
is a sketch showing a two-piece matrix connector incorporating power contacts with one connector piece exploded;
FIG. 10
is a sketch showing a second piece of the matrix connector of
FIG. 9
with a second connector piece exploded;
FIG. 11A
is a sketch showing a power wafer of the connector of
FIG. 10
in an exploded view; and
FIG. 11B
is a sketch showing the power wafer of
FIG. 11A
assembled.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
shows a portion of a matrix assembly
100
. Assembly
100
includes a vertical board
112
and a horizontal board
116
. A type A connector
110
is mounted to board
112
and a type B connector
114
is mounted to board
116
. The connectors
110
and
114
each have numerous signal and ground contact tails
230
,
330
that make electrical connection to circuit traces on or within the boards
112
,
116
(see FIGS.
2
and
3
). Additionally, each of the connectors
110
,
114
have conducting elements with mating portions
232
(
FIG. 2
) and
832
(FIG.
8
). The mating portions are positioned so that when the type A connector and the type B connector are mated, numerous circuit paths will be completed between board
112
and board
116
.
In the illustrated example, boards
112
and
116
are conventional printed circuit boards as traditionally found in a matrix assembly. It will be appreciated that only very small boards are shown. In a commercial implementation, each board would be larger and contain numerous electronic devices.
Also, it should be appreciated that a commercial embodiment of a matrix assembly is likely to have more than just two boards. For example, a matrix assembly is more useful when multiple horizontal boards are connected to the same vertical board. In this way, the vertical board can route electrical signals between the horizontal boards. A matrix assembly is likely to be even more useful if multiple vertical boards are included along with multiple horizontal boards. In this way, a system designer has significant flexibility in routing signals between printed circuit boards.
In the embodiment illustrated in
FIG. 1
, type A connector
110
includes a housing
118
and a cap
120
. As will be described in greater detail below, the connector
110
is made up of a plurality of subassemblies or wafers (e.g.,
310
of
FIGS. 3 and 8A
) that contains signal conductors.
Housing
118
holds the rear portions of the wafers. In the illustrated embodiment, housing
118
is an insulative housing, preferably made of plastic or other material typically used in the manufacture of electrical connectors.
Cap
120
is also made of insulative material in the illustrated embodiment. Cap
120
provides the mating face of type A connector
110
. It positions the contact portions of the conductive members inside the connector and also protects them from physical damage.
Cap
120
further aids in providing “float” or “compliance.” Cap
120
includes features, such as tapered surface
121
that generates force in a direction that tends to align caps
120
and
124
(of type B connector
114
) as the two connectors are mated. The compliance mechanism of the connector is described in greater detail below.
Likewise, type B connector
114
includes a housing
122
and a cap
124
. As with the type A connector, housing
122
holds wafers (
210
of
FIG. 2
) in position. Cap
124
also positions and protects the contact portions of the conductive members inside the connector. Cap
124
includes a shroud, such as formed by projecting walls
126
(see FIG.
1
), to protect the contacts.
The shroud also serves to provide alignment between the type A and type B connectors as they mate. In the illustrated embodiment, cap
120
fits within the shroud. When cap
120
is engaged in the shroud, the contact elements from the type A connector align with the contact elements in the type B connector.
To further help with the alignment, walls
126
include alignment features
128
. Alignment features
128
engage with complementary alignment features on cap
120
to aid in guiding the connectors into a mating position. Preferably, the alignment features have tapered surfaces, such as
130
(FIG.
2
), to guide the front face of the connectors into the appropriate position in the Y direction. Tapered surfaces
132
(
FIG. 2
) engage complementary features on the mating connector to guide the connectors into appropriate alignment in the X direction. In the illustrated embodiment, cap
124
is compliant and pressing a mating connector into cap
124
aligns cap
124
with the mating connector.
The type B connector
114
is shown in exploded view in
FIG. 2. A
plurality of wafers
210
are shown stacked side by side. The wafers fit within housing
122
. In the illustrated embodiment, each wafer contains features, such as
220
and
222
, that engage other features within housing
122
to hold the wafers in place.
Various engagement features might be used. In the illustrated embodiment, feature
220
includes a tab that engages a slot
221
on the housing
122
. If desired, feature
220
might also include a latch to prevent the wafer from sliding out once engaged. Feature
222
includes a tab or boss or similar protrusion to engage a complementary opening on the inside of housing
122
.
Each wafer includes conducting elements. In the preferred embodiment, some of the conducting elements are designed to carry signals. Others of the conducting elements are intended to be connected to ground. The ground conductors also can serve as shields to reduce distortion carried on the signal conductors.
The conducting elements are connected to the printed circuit board
116
. Contact tails
230
project from a lower edge of the wafer. In the illustrated embodiment, the contact tails are press fit contacts that engage holes in the surface of a printed circuit board.
The conducting elements also include portions that extend from the forward edge of wafer
210
. In the preferred embodiment, the signal conductors extend from the forward edge of the wafer as mating contact portions
232
. In
FIG. 2
, the mating contact portions are illustrated as blades. However, it should be appreciated that multiple forms of mating contacts are known—such as pins, receptacles or beams—and could be used.
The ground conductors in the preferred embodiment take the shape of shield plates
236
that lies flat against the major surface of the wafer. Hubs
238
extend from wafer
210
and pass through holes in plate
236
, thereby holding it securely to the wafer.
Ground plate
236
includes contact tails
230
that press fit into ground holes in printed circuit board
116
. Ground plate
236
also includes a connection portion that extends from the forward edge of the wafer. The forward edge of ground plate
236
includes contacts
234
that are adapted to mate to shields
250
.
As shown in
FIG. 2
, each of the wafers
210
contains a column of signal contacts. Shield plate
236
shields a column from the column provided by an adjacent wafer in the body of the wafer.
When the wafers are assembled side by side, the columns of signal contacts make a rectangular array of signal conductors. In the illustrated embodiment, the array will be a square array. Each wafer contains a column of fourteen signal contacts and fourteen wafers are aligned side by side to make fourteen rows of fourteen contacts each.
Shields
250
are positioned between the rows of signal contacts in the region of the mating contact portions. Shield plates
250
are electrically connected to the shield plates
236
. Each shield plate
250
engages a contact
234
on each of the shields
236
(see FIG.
4
C). Much of the length of each signal conductor is adjacent to either one of the shield plates
236
or one of the shields
250
. In this way, shielding is provided substantially over the length of the signal conductors.
In between the body of the wafer and the contact portions are compliant portions
240
, which is described in greater detail below. These complaint portions allow the portions of the wafer containing the mating contacts to move relative to the rear portion of the wafers. Also, it should be noted that the attachment points of the wafers, such as
220
and
222
are on the rear portions. Thus, while the rear portion of the wafers are fixed to the housing and to the printed circuit board, the mating contact portions can move relative to the board and the housing. In the preferred embodiment, the compliant portions adjusts for mis-alignment between the mating pieces of the connectors.
The shield plates
250
fit into the cap
124
and are secured with any convenient means. For example, each edge of the shield plates
250
might fit into a slot in a wall of cap
124
. However, in the illustrated embodiment, cap
124
has a floor
252
that includes numerous openings. Each shield plate
250
is cut with slits creating fingers
254
. Each of the fingers projects through an opening in floor
252
, creating a mating surface within the shroud created by the walls
126
of cap
124
. In the illustrated embodiment, the shield plates are held firmly to the cap through an interference fit.
Mating portions
232
project through openings in floor
252
. Preferably, the openings are so small that they create an interference fit with the mating portions
232
to secure them to cap
124
. Likewise, they are situated to provide a mating area within shroud created by the walls
126
of cap
124
.
In the preferred embodiment, cap
124
is not rigidly attached to housing
122
. A means of attachment is used to provide compliance to cap portion
124
. Because there is compliance in cap portion
124
, there is also compliance in the mating area within cap
124
. Significantly, if the connectors
110
and
114
are misaligned, the compliance allows the mating contacts of each connector to properly align nonetheless.
In the illustrated embodiment, the compliance is provided with attachment features
260
on cap
124
and attachment features
262
on housing
122
that allow a sliding form of attachment in combination with compliance sections
240
on all of the conductors. Preferably, the specific form of attachment allows the cap to move in the plane illustrated as the X-Y plane in FIG.
2
. It is also preferable that the attachment not allow compliance in the direction illustrated as Z. As the connector pieces
110
and
114
are pushed together for mating, it is desirable that the mating portions come into alignment in the X-Y plane. A rigid attachment in the Z direction is desirable so that sufficient mating force can be generated.
As described above, the electrical conductors have portions that are rigidly attached to the printed circuit board
116
. They also have portions that are attached to cap
124
. But, these two portions are separated by compliant portions
240
. In this way, electrical connections can be made through the connector while still providing the compliance necessary to ensure proper mating.
Turning now to
FIG. 3
, type A connector
110
is shown in exploded view. The connector contains a plurality of wafers
310
. As with wafers
210
, wafers
310
include a plurality of signal conductors and a shield
336
. A plurality of contact tails
330
extend from a lower surface of the wafers for attachment to printed circuit board
112
.
Wafers
310
are stacked side-by-side, with their major surfaces in parallel. The wafers are secured to housing
118
. Attachment features
322
on the wafers
310
engage slots
321
in the housing
118
. Likewise, features
320
engage other slots in housing
118
.
In the illustrated embodiment, each wafer includes fourteen electrically separate conductors that are intended to act as signal conductors. Fourteen wafers are stacked side by side to make a rectangular array with the same number of rows and columns. And, as with the type B connector
114
, the pitch between the contacts in a wafer is the same as the spacing between adjacent wafers. Thus, despite the fact that the wafers in the type A connector
110
and the wafers in the type B connector
114
are orthogonal, each connector has a mating interface with contacts in a rectangular array with contact spacings that allows the conductors to mate.
The conductors of wafers
310
have mating portions that extend at the forward edge of the wafer. In the preferred embodiment, these mating portions fit within recesses formed in the lower surface
352
of cap
120
. As in a traditional connector, the recesses within cap
120
are accessible through openings in the mating face of cap
120
. As connector
110
is mated with connector
114
, cap
120
fits within the walls of cap
124
, bringing the mating contact portions of the conductors from connector
110
into the mating area. The mating portions of the signal conductors from connector
114
pass through the openings in the mating face of cap
120
and make electrical contact with the mating contact portions of the conductors from connector
110
.
In the illustrated embodiment, the mating contact portions of the signal conductors of connector
114
are blades. The mating contact portions of the signal conductors from connector
110
must be of the type that makes a suitable electrical connection to a blade. Preferably, the mating contact portions of the signal conductors in connector
110
will include one or more beams bent in such a way to generate spring force against that blade. Preferably, two separate beams positioned in parallel to create a split beam type contact create the mating contact portion of the signal conductors in connector
110
.
The mating contact portions for the ground conductors in connector
114
are the fingers
254
. Fingers
254
also provide a blade-like mating contact portion. As can be seen in
FIG. 3
, shields
336
also have fingers
354
in their mating areas. However, rather than being completely flat, fingers
354
have beams
830
(
FIG. 8
) cut in them. In the illustrated embodiment, the beams are secured to the shield plate at two ends, but bent out the plane of the shield in the middle. This arrangement allows the beams to generate a spring force.
During mating, fingers
254
from one of the shields
250
will be parallel to and adjacent fingers
354
from one of the shields
336
. The spring force generated by the beams
830
will create the necessary electrical connection between the shields. In this way, the shields in connector
110
are electrically connected to the shields in connector
114
.
Turning now to
FIG. 4
, a manufacturing process for wafer
210
is illustrated.
FIG. 4A
shows a lead frame
410
. The lead frame
410
is stamped from a sheet of conductive material of the type traditionally used to make signal contacts in an electrical connector. Preferably, a copper alloy is used.
When lead frame
410
is stamped, carrier strips
412
are left to allow easier handling of the lead frame. The lead frame is held to the carrier strip
412
by a plurality of tie bars
414
. And, the signal conductors
416
are joined by tie bars
415
. The tie bars
415
are eventually cut to leave a plurality of electrically separate signal contacts
416
. And the tie bars
414
are eventually cut to separate the wafer
210
from the carrier strips.
As can be seen, each signal contact has a contact tail
230
, a mating contact portion
232
, a compliant portion
240
and an intermediate portion, between the compliant portion and the contact tail.
In a preferred embodiment, multiple lead frames are stamped from a long strip of conductive material. The lead frames are joined by the carrier strips
412
and wound on a reel (not shown). In this way, an entire reel of wafers
210
can be processed and easily handled. However, for simplicity, only a portion of the reel is shown.
Once the lead frame
410
is stamped to the required shape, a forming operation might be used. The forming operation creates any features on the lead frame
410
that are out of the plane of the sheet of material used to make the lead frame. The precise shape and amount of forming will depend on the design of the signal contact. In the illustrated embodiment, the mating contact portions
232
are bent at a 90° angle relative to the plane of the lead frame
410
. This bend places the smooth, flat surface of the contact portion perpendicular to the plane of lead frame
410
. In use, the mating contact portion from the connector
110
will press against the flat surface of the contact portion
232
when bent at this angle. It is preferable to have the contacts mate on a smooth surface.
FIG. 4B
illustrates another step in the manufacture of the wafer
210
. The lead frame is placed in a mold and an insulator
420
is molded around the intermediate portions of the signal conductors. Insulator
420
locks the signal conductors
416
in place. It also provides mechanical support to the wafer
210
and insulates the signal conductors to avoid electrical shorts. Insulator
420
might be any suitable plastic, such as those which are traditionally used in the manufacture of electrical connectors.
Insulator
420
is shown with a plurality of hubs
238
molded therein for later attachment of a shield. The surface of insulator
420
is molded to receive the shield
236
.
FIG. 4B
also shows a forward insulator
422
molded across the signal conductors at the proximal end of the signal contacts
232
. Forward insulator holds the signal contacts together when the tie bars are severed. It also provides a point of attachment for a manufacturing tool that can be used to press the signal contact portion of the wafers into cap
124
.
FIG. 4C
shows a shield
236
before attachment to wafer
210
. As with the signal contacts, a plurality of shields are stamped from a sheet of conductive material and held together on carrier strips. Shield
236
is stamped with a plurality of holes
430
to engage the hubs
238
. The positioning of holes
430
and hubs
238
holds a generally planar intermediate portion adjacent the insulator
420
.
Shield
236
is also stamped with a plurality of compliant portions
240
, extending from the intermediate portion. In the illustrated embodiment, there are approximately the same number of compliant portions
240
on each shield
236
as there are signal conductors in the wafer. This number of compliant portions provides for an appropriate flow of ground current and also the appropriate amount of compliance. More complaint portions
240
additionally provide greater shielding.
A forward portion
434
extends from the compliant portions
240
. Forward portion
434
is secured to cap
124
. Shield contacts
234
are formed on forward portion
434
.
As with the signal contacts, the shield
236
might be formed after stamping to provide features that extend out of the plane of the conductive sheet used to make the shield. Contact portions
230
also extend from the intermediate portion of shield
236
and can be formed.
FIG. 4D
shows wafer
210
at a later stage of assembly. A shield plate
236
is overlaid on the insulator
420
. The shield plate is pressed to engage the hubs
238
in holes
430
. The tie bars
414
are cut to release wafer
210
from the carrier strips
412
. Wafer
210
is then ready for insertion into housing
122
.
Other manufacturing operations as known in the art might be included in addition to the ones shown herein. For example, it might be desirable to coin the edges of the signal contact portions
232
. Alternatively, it might be advantageous to gold plate some of the contact portions.
FIG. 5
shows additional details of a compliant portion
240
. As can be seen, the compliant portion is generally elongated. However, in the illustrated embodiment, the compliant portion includes bends to increase the amount of compliance. In the illustrated embodiment, bends
510
and
512
are included. Preferably, bends
510
and
512
bend in opposite directions to provide compliance in the X and Y directions, without permanent deformation of the contact, thereby providing a self-centering feature to the connector. The number, size and shape of the bends could be varied. However, it is preferable that the compliant portion include smooth bends to provide more desirable electrical properties. In addition, the curved portions additionally provide compliance in the Z direction. While it is generally preferred that the caps engage to preclude motion in the Z direction, there will be some manufacturing tolerances that allow some motion in that direction.
In the preferred embodiment, the compliant portions are approximately 8 mm long made from material with a cross section that is approximately 8 mils square. The amount of compliance can be increased by increasing the length of the compliant section or increasing the radius or number of curved portions. Conversely, if less compliance is needed, the curves would be removed, the segments shortened or a thicker material might be used.
Turning to
FIG. 6
, additional details of features of shield
236
are shown.
FIG. 6A
shows a contact
234
. The contact is stamped into forward portion
434
. A gap
610
is provided. Slots
612
and
614
are also stamped in the shield, leaving beams
618
and
620
.
Gap
610
is narrower than the thickness of a shield
250
. Thus, as shield
250
is pressed into the gap
610
, beams
618
and
620
will be deformed back into slots
612
and
614
. However, beams
618
and
620
will generate a substantial amount of force against shield
250
. Preferably, the amount of force is sufficient to create a gas tight seal between shield
250
and shield
236
.
Turning to
FIG. 6B
, details of contact tail
230
on shield
236
are shown. In the preferred embodiment, contact tail
230
includes a press-fit portion
650
. Tab
652
joins press fit portion
650
to the intermediate portion of shield
236
. Here, tab
652
has been bent out of the plane of the intermediate portion of shield
236
. The bend aligns the press fit portion
650
with the press fit sections of the signal conductors.
FIG. 4A
shows that the contact tails
230
of the signal conductors
416
are grouped in pairs with a gap in between each pair. When shield
236
is installed on a wafer
210
, each of the contact tails for the shield
236
will fit between an adjacent pair of signal conductors.
Turning now to
FIG. 7
, additional details of the compliant attachment between cap
124
and housing
122
are shown. In the illustrated embodiment, the attachment features are on two opposing sides of the housing
122
. There are three sets of attachment features
260
and
262
aligned to engage.
Feature
260
includes a tab
716
held away from the surface
714
of cap
124
by a projection
720
. This arrangement creates a slot
752
between surface
714
and lip
716
.
Feature
262
includes an opening
722
with a rear wall
712
. A lip
718
extends into the opening
722
a distance spaced from rear wall
712
. This arrangement creates a slot
750
between rear wall
712
and lip
718
.
In a preferred embodiment, slot
752
is the same thickness as the width of lip
718
and slot
750
is the same width as the thickness of tab
716
. Thus, when attachment features
260
and
262
are engaged, tab
716
is held in slot
750
and lip
718
is held in slot
752
. Neither has sufficient play to move a significant amount in the Z direction.
However, the fit should not be so tight as to create an interference fit that precludes all movement. Tab
716
should be able to slide in the X-Y direction within slot
750
and lip
718
should be able to slide in the X-Y direction in slot
752
.
Attachment features
262
includes stops that prevent cap
124
from sliding so far as to become disengaged from housing
122
. Stop
754
prevents excessive motion to the left in FIG.
7
A. Stop
756
prevents excessive motion to the right in FIG.
7
A. Up motion is restrained by lip
718
pressing against projection
720
. Down motion is restrained when an alignment feature
260
presses against the alignment feature
262
below it.
However, as shown more clearly in the partially cut away view of the engaged alignment features, there is sufficient play between the features
260
and
262
to allow motion in the X-Y plane. For example, projection
720
is made narrow enough to provide 0.5 mm of movement before either stop
754
or
756
is engaged. And, slot
752
is long enough to allow 0.5 mm of movement before lip
718
engages tab
716
or attachment feature
260
bottoms on the attachment feature
262
below it. To provide this amount of compliance, the compliant portions are made approximately 8 mm long of material that is approximately 8 mils square.
Turning to
FIG. 8
, details of a wafer
310
are shown. As with wafer
210
, wafer
310
is preferably made by first embedding a lead frame containing signal contacts in an insulator
820
to make a signal contact subassembly. The lead frame is stamped from a sheet of conductive metal and then formed into the desired shape. In the illustrated embodiment, mating contact portions
832
are formed into split beam type contacts by first stamping two beams and then bending the beams to a shape which generates adequate spring force for mating. Once the lead frame is encapsulated in insulator
820
, the individual signal contacts are severed.
Separately, a shield
336
is stamped and formed. In the preferred embodiment, it is attached to insulator
820
to create a shielded subassembly. Holes
834
engage hubs
836
to hold shield
336
in place.
FIG. 8A
shows the wafer with the shield attached.
FIG. 8B
shows the signal contact subassembly and the shield separately.
Shield
336
also has features stamped and formed in it for making electrical connection. A contact tail
330
is attached to a tab
852
. Tab
852
is bent such that when shield
336
is attached to insulator
820
, the contact tails
330
of the shield
336
are aligned with the contact tails from the signal contacts. As described above, the contact tails
330
are intended to make electrical connection to signal traces within a printed circuit board.
Shield
336
also makes an electrical connection to a shield
250
in a mating connector. A beam
830
is stamped in each finger
354
. The beam is bent out of the plane of shield
336
so that, as fingers
354
slide against the shield
250
, beams
830
are pressed back into the plane of the shield, thereby generating the required spring force to make an electrical connection between the shields in the mating connectors.
In this way, a connector that is easy to manufacture is provided for a matrix application. Waferized construction is used for both halves of the connector. And, the connector is self-aligning, allowing it to correct for greater positional inaccuracies in the manufacture of the matrix assembly, making it easier to manufacture an electronic system using a matrix configuration of printed circuit boards. A self-aligning connector is particularly important for a matrix assembly because without a single structure, like a backplane or a midplane, to provide references, there is greater opportunity for manufacturing tolerances of the boards to result in mis-alignment of the connectors. The designs shown herein are capable of mating despite misalignment of over 1 mm.
Furthermore, the design allows for shielding over substantially the full length of the signal contact portions. Shielding adjacent the signal contacts reduces crosstalk between signal conductors. It can also be important to controlling the impedance of the signal conductors.
Turning now to
FIG. 9
, an alternative configuration of a matrix connector is shown. As above, the matrix connector of
FIG. 9
is a two piece connector. However, this connector incorporates power contacts. Power contacts are wider than signal contacts to provide a greater current carrying capacity.
FIG. 9
illustrates the preferred embodiment in which a connector carries both signal and power contacts. In this way, both signals and power can be transmitted from one board to the other, but only as many power contacts as are required to power the board are used. The remaining space in the connector can be used for signal conductors so that the signal density of the interconnection system is maximized.
FIG. 9
shows one connector piece
910
, which may be considered a “type A” connector because it is intended to be mounted in the same orientation as the type A connectors illustrated above. The second connector piece
920
is shown in an exploded view, which might be considered a type B connector because it is intended to be mounted in the same orientation as the type B connectors described above. In the preferred embodiment, the connector pieces
910
and
920
will be approximately the same size as connector pieces
110
and
114
. In this way, they can be readily incorporated into the same interconnection system as connectors that carry only signal conductors, as shown in
FIGS. 1-8
.
Connector piece
920
includes a housing
922
. Preferably, housing
922
is made of an insulative material, such as plastic. Preferably, housing
922
is molded to the desired shape.
A plurality of power blade assemblies
924
are inserted into housing
922
. The number of blade assemblies depends on the amount of power that needs to be routed through the connector. In the example of
FIG. 9
, each power blade assembly includes four blades in the same space that each signal wafer
210
includes
14
signal contacts. The power blades are therefore much wider, carrying on the order of 5-10 Amperes, depending on the specific shape and material from which they are assembled. Each of the power blade assemblies
924
has four independent blades—which allows each assembly to carry up to four different voltage levels.
The number of power blade assemblies
924
is not important to the invention and will preferably be picked to provide a sufficient current carrying capacity for each level of power required in the system. However, the power blade assemblies do not fill housing
922
. Housing
922
also includes signal conductors.
Signal housing insert
926
fits within housing
922
. Signal housing insert
926
receives a plurality of signal wafers
928
in wafer attachment features
927
. In the illustrated embodiment, the wafer attachment features are slots into which complementary tabs or hubs are inserted.
Signal wafers
928
are formed generally like signal wafers
210
. Preferably, they will include the same form of compliant contacts. However signal wafers
928
differ from signal wafers
210
in the number of signal conductors in each wafer. Signal wafers
928
have fewer signal conductors to make them small enough to fit in the space in housing
922
not occupied by the power blade assemblies
924
.
Like wafers
210
, signal wafers
928
include shields that include contacts along their forward edges like contacts
234
. These contacts allow shields
930
to be connected to signal wafers
928
in the same fashion that shields
250
are connected to wafers
210
.
Cap
932
attaches to the mating end of connector piece
920
. Cap
932
is compliantly mounted to the housing
922
, to provide compliance similar to that provided between cap
124
and housing
122
. Attachment feature
970
engages attachment feature
972
on signal housing insert
926
. Signal housing insert, because it is attached to the rear portion of the signal wafers which are in turn secured to the printed circuit board, tends to be fixed relative to the circuit board. However, attachment features
970
and
972
allow compliance—at least in the X-Y plane, as defined above. Similarly, attachment features
974
on cap
932
and attachment features
976
on housing
922
also allow compliance.
To align the connector pieces
910
and
920
, alignment features are included on the connector pieces. Tab
964
fits within recess
962
. As discussed above, these features have tapered surfaces that guide the connectors into alignment. Other surfaces of the connector housing can likewise be tapered to guide the two connectors into alignment.
Each of the power blade assemblies
924
contains several power blades. Each power blade has a rear portion
940
. The rear portions contain contact tails
942
that are intended for mounting to a printed circuit board. In the illustrated embodiment, each power contact has three contact tails
942
for greater current carrying capacity. In the preferred configuration, each of the rear portions is bent at a right angle.
The rear portions
940
of the power blades in each power blade assembly
924
is held in a tie bar
944
. Preferably, tie bar
944
is an insulative material and might, for example, be insert molded over the power blades. Tie bar
944
holds the power blades together and also provides a manner to attach the power blade assemblies
924
to housing
922
.
Each tie bar includes tabs
950
on opposing ends. Tabs
950
slide into slots
952
in housing
922
. In this way, the front portion of each of the power blade assemblies
924
is held in the housing. Each of the power blades includes a pair of opposing tabs
954
. Each of the power blade assemblies
924
is inserted into housing
922
until the tabs
954
engage slots
956
, thereby locking the rear portions
940
of the power blades in housing
922
.
Each of the power blades has a compliant portion
946
, resembling compliant portion
240
, described above. Each compliant portion
946
joins the rear portion
940
to a mating contact portion
948
. The compliant portion
946
consists of one or more elongated members. The elongated members might be curved, to provide greater compliance, or straight. The number of elongated members will depend on the specific requirements of the application, such as the amount of current that must be carried and the amount of compliance needed.
The mating contact portions
948
are inserted into power contact cavities
958
of the cap
932
. In the illustrated embodiment, mating contact portions form pad type contacts that mate with beams in the opposing connector. Each of the power contact cavities
958
has slots
959
formed in its side walls. Each of the mating contact portions
948
is inserted into one of the slots
959
, thereby securing the mating contact portion to cap
932
while exposing a surface of each mating contact portion to the power contact cavity
958
.
Cap
932
also includes a signal contact cavity
960
. Signal contact cavity
960
resembles cap
124
, but sized for the signal wafers
928
.
Turning now to
FIG. 10
, an exploded view of connector
910
is shown. Multiple wafers are held within housing
1010
. Preferably, housing
1010
is made of an insulative material, such as plastic. In the preferred embodiment, housing
1010
is molded from plastic.
Both signal and power wafers are inserted into housing
1010
. Signal wafers
310
can be the same signal wafers used to make connector
110
. Mounting features, such as tabs and slots hold the wafers in housing
1010
. Power wafer subassemblies
1012
are also held in housing
1010
.
Connector
910
is shown with a two piece cap. Signal cap
1014
has a similar shape and function to cap
120
. It is attached to the forward portions of signal wafers
310
. However, it has a reduced number of columns because fewer signal wafers are used. In the example of
FIG. 10
, only four columns are shown.
Power cap
1016
receives the front portions of power wafer subassemblies
1012
. Power cap is also attached to housing
1010
. Projections
1018
engage complementary features in housing
1010
and might, for example engage with an interference fit or a snap fit.
Power cap
1016
also provides a place of attachment for signal cap
1014
. The side wall of power cap
1016
includes slots
1020
. T-shaped tabs from signal cap
1014
extend into slots
1020
, thereby holding signal cap
1014
against power cap
1016
.
Turning to
FIG. 11
, details of a power subassembly
1012
are shown.
FIG. 11A
shows that each power wafer subassembly
1012
is, in the illustrated embodiment, made from two complimentary wafers
1110
and
1112
and a lead insulator
1114
.
Each of the power wafers
1110
and
1112
includes power conductors, preferably embedded in an insulator
1120
or
1122
. The number of power conductors in each of the power wafers
1110
and
1112
preferably matches the number of blades in each blade subassembly
924
. In this way, each of the power conductors can align and mate when connectors
910
and
920
are mated.
Each of the power conductors includes contact tails
1124
that extend from a lower surface of the insulators
1120
and
1122
. As with the power subassemblies in connector
920
, multiple contact tails are preferably used for each power contact. In the illustrated embodiment, three contact tails for each power conductor are used as a good compromise between current carrying capacity and number of independent power conductors.
Each of the power conductors also includes mating contact portions extending from a forward edge of the insulators
1120
and
1122
. In the illustrated embodiment, the mating contact portions are in the shape of bifurcated beams
1116
and
1118
on wafers
1110
and
1112
, respectively. Each of the bifurcated beams
1116
and
1118
has a curved portion that curves away from the other wafer that is near the leading edge
1132
of the mating contact portion.
The insulators include features that allow the wafers
1110
and
1112
to be locked together.
FIG. 11A
shows hubs
1126
extending from a surface of insulator
1122
. Hubs
1126
engage complementary openings in insulator
1120
. In the illustrated embodiment, hubs
1126
make an interference fit to hold the wafers together. Though other attachment mechanisms, including snap fit, could be used to hold the wafers together.
Lead insulator
1114
fits over the mating contact portions
1116
and
1118
. Lead insulator
1114
includes a center wall
1144
that separates the mating contact portions of wafers
1110
and
1112
. Center wall
1144
includes grooves
1140
that receive one of the mating contact portions
1118
or
1116
. In this way, each of the mating contact portions is insulated from the others.
Lead insulator
1114
can be secured to the rest of the assembly in any convenient way. For example, snap-fit features might hold lead insulator
1114
to insulators
1120
or
1122
. Or, an interference fit between portions of the bifurcated beams
1116
and
1118
and the grooves
1140
might alternatively hold lead insulator
1114
in place.
The forward end of each of the grooves
1140
has a lip
1142
. The leading edge
1132
of each of the mating contact portions fits under the lip
1142
, presenting a smooth leading edge of the power wafer subassembly.
As can be seen more clearly in
FIG. 11B
, the assembled power wafer subassembly
1012
has curved portions
1130
of each of the power conductors facing outwards. When connectors
910
and
920
mate, the mating contact portions of the
1116
and
1118
will be inserted into power contact cavities
958
where curved portions
1130
will press outwards against mating portions
948
from the power conductors in connector
920
. In this way, a separable connection between the two connectors will be formed.
In the illustrated embodiment, each power wafer assembly
1012
has a width approximately three times that of a signal wafer
310
. Thus, connector
910
is shown to have three power wafer assemblies
1012
and four signal wafers
310
. The outer wall of power cap
1016
adjacent signal cap
1014
also occupies the thickness of approximately one wafer. Thus, connector
910
is shown to have a square mating face of approximately the same size as the mating faces of connectors
110
and
114
. In forming an interconnection system, it is often preferable to have connectors, even those of different configurations, to occupy the same space. And, when laying out a matrix interconnection system, it is preferable for the connectors to be square. However, the precise number of power and signal wafers that are in each connector
910
and
920
, as well as the connector dimensions can be selected to meet specific design requirements.
Having described one embodiment, numerous alternative embodiments or variations might be made. For example, the orientation of the boards was described as horizontal and vertical. These dimensions are used in the illustration solely to give a frame of reference for the description of the preferred embodiment. In a commercial embodiment, the boards might be mounted with many different orientations driven by the requirements of the electronic assembly. Also, it should be appreciated that the type A and type B connectors need not be mounted on a board with any particular orientation. For example, the locations of the type A and type B connectors might be reversed.
It is also not necessary that the wafers be held in a housing, as shown. An organizer of any type might be used to position the wafers. For example, a metal strip having holes in which to receive features from each of the wafers could be used. Or, the wafers might be held in position by securing the wafers into a block with sufficient rigidity. The wafers, for example, might be held together with adhesive. Likewise, in an application in which the mechanical positioning of the contact tails is not critical, the housing might be eliminated.
As an example of another alternative, it should be appreciated that compliance in a plane was provided in the preferred embodiment by attachment features between cap and housing that allowed motion in two orthogonal directions in the X-Y plane. As an alternative, attachment features that allow compliance in only one direction might be provided with a type B connector. Compliance in the orthogonal direction might be provided by a similar structure on the type A connector—with the combination of the two thereby providing compliance in the plane.
The shield plates are shown in the mating area to be divided into fingers. In the illustrated embodiment, there are half as many fingers as there are signal conductors. In such an arrangement, signal conductors are grouped in pairs adjacent shield fingers. Such an embodiment is useful for making a differential connector in which one signal is carried on a pair of signal conductors. To further enhance the performance of the electrical connector, slits might be cut in the various shield plates. For example, slits might be cut in shields
236
to remove the conducting material between the signal conductors that form a pair carrying a differential signal. Conversely, slits might be cut in shield plates
336
to remove conducting material between the pairs of signal conductors, thereby increasing the electrical isolation between the signals carried by each pair.
Also, it should be appreciated that shields such as
236
are illustrated as having been stamped from a sheet of metal. A shield plate might alternatively be created by a conducting layer on the plastic.
Additionally, contacts
234
are shown with two beams pressing against opposing sides of shield
250
. It would be possible to make an electrical contact with a single beam pressing against one side of the shield. Alternatively, it is not necessary that the beams be secured at both ends. A cantilevered beam might alternatively be used.
As another variation, it might be desirable to form cap
124
or cap
932
from a material with greater structural strength than plastic. Because the alignment of the connectors is achieved by forcing the connectors together until the walls of cap
124
or cap
932
guide the cap from the mating connector into position, there can be significant force placed on the walls of caps during mating—depending on the number of conductors in a connector and the degree of misalignment between printed circuit boards. An alternative would be to cast cap
124
or cap
932
from anodized aluminum or otherwise form it from metal. If a conducting metal is used, it would then be necessary to insulate the signal conductors from the metal to avoid shorting the signal conductors. Plastic grommets or other insulator might be inserted in the holes in floor
252
to insulate the signal conductors from the metal. It might also be desirable to insulate the ground plates from the metal.
Also, it should be appreciated that alignment features such as
128
are illustrative of the shape and position of alignment features. More generally, any tapered surfaces that act to urge the connector pieces into proper alignment might be used. And, it is not necessary that the alignment features be formed into the connector pieces themselves. Separate alignment structures, such as alignment pins and holes might be attached to the connector housings or caps.
Further, it is not necessary that the wafers be manufactured by molding plastic over signal contacts. As an alternative way to embed the conductors in the insulator, an insulator might be molded over the shield piece, leaving space for the signal conductors in the insulator. The signal conductors might then be pressed into those spaces and affixed to the insulator. The signal conductors might be affixed to the insulator by using barbs on the signal conductors. Or features could be included in either the conductors or insulators to form an interference fit. Or, an over-molding of insulator might be applied to seal the space around the signal conductors, holding them in the insulator.
Also, it is not necessary that the shields be affixed to the signal subassemblies at all. It would be possible to construct a connector in which loose shield pieces are placed between signal subassemblies.
Another variation might be to place insulating members between adjacent signal conductors or between shield members and signal conductors. For example, shield
336
, particularly fingers
354
, might be coated with an insulator to prevent contact to signal conductors. Or, forward insulator
422
might be expanded to include openings to receive the contact portions. Thus, rather than insert the contacts into openings in cap
124
, the openings would be already molded around the contacts and cap
124
would resemble more of an open frame.
Therefore, the invention should be limited only by the spirit and scope of the appended claims.
Claims
- 1. An electrical connector comprising:a) a support member; b) a plurality of power conductors within the support member, wherein the power conductors are bent at a right angle thereby bounding two sides of a rectangular area; c) a plurality of signal wafers connected to the support member, each wafer having a plurality of signal conductors, with the signal wafers stacked in parallel in the rectangular area; and d) each of the signal conductors has a single contact tail extending therefrom and each of the power conductor has at lest three contact tails extending therefrom.
- 2. An electrical connector comprising:a) a support member; b) a plurality of power conductors within the support member, wherein the power conductors are bent at a right angle thereby bounding two sides of a rectangular area; c) a plurality of signal wafers connected to the support member, each wafer having a plurality of signal conductors, with the signal wafers stacked in parallel in the rectangular area; d) an insulative cap, the insulative cap having a plurality of cavities therein, wherein each of the plurality of power conductors has a mating contact portion inserted into one of the cavities; and e) each of the cavities has opposing side walls with slots formed therein and wherein the mating contact portions are inserted into the slots leaving a portion of the mating contact portion of each power conductor exposed.
- 3. An electrical connector assembly having a first electrical connector and a second electrical connector adapted to mate with the first electrical connector, which comprises:the first electrical connector comprising: a) a support member; b) a plurality of power conductors within the support member, wherein the power conductors are bent at a right angle thereby bounding two sides of a rectangular area; c) a plurality of signal wafers connected to the support member, each wafer having a plurality of signal conductors, with the signal wafers stacked in parallel in the rectangular area; the second electrical connector comprising: a) a second support member; b) a plurality of power wafers aligned in parallel, each of the power wafers having an insulative housing and a plurality of power conductors embedded therein; c) a plurality of signal wafers aligned in parallel, each of the signal wafers having an insulative housing and a plurality of signal contacts embedded therein; d) wherein the signal wafers and the power wafers are aligned in parallel; and e) wherein the power wafers are organized in subassemblies, each subassembly comprising two adjacent power wafers, each power wafer having a mating contact portion extending from a forward edge thereof with an insulator disposed between the mating contact portion of the adjacent wafers.
- 4. An electrical connector assembly comprising:a) a first electrical connector, comprising: i) a first support member; ii) a plurality of wafers, held in parallel to the first support member, each wafer having a plurality of signal conductors with mating contact portions held in a line, each signal conductor having a first width; iii) a first plurality of power conductors held to the first support member, each having a second width greater than the first width, each said power conductor bent at a right angle; and b) a second electrical connector, adapted to mate to the first electrical connector, comprising: i) a second support member; ii) a second plurality of wafers, held in parallel to the support member, each wafer having a plurality of signal conductors with mating contact portions held in a line; iii) a second plurality of power conductors held to the second support member, each said power conductor bent at a right angle.
- 5. The electrical connector of claim 4 wherein the first plurality of wafers holds the signal conductors in a first line in a mating plane and the second plurality of wafers holds the signal conductors in a second line in the mating plane, with the first lines and the second lines orthogonal.
- 6. The electrical connector of claim 4 wherein the first plurality of power conductors and the second plurality of power conductors are each held in groups, with the first plurality of power conductors held in first groups by insulative members joining groups of power conductors, the power conductors within the first groups having mating contact portions held in a first power contact line, with the first power contact line being orthogonal to the first line mating contact portions of the signal conductors.
- 7. The electrical connector of claim 4 wherein the first support member comprises an insulative housing.
- 8. The electrical connector of claim 7 whereina) each power conductor has a first end with the mating contact portion thereon and a second end, with contact tails attached thereto; and b) the insulative housing has a plurality of slots therein, with a portion of second end of each power conductor engaged within at least one of the plurality of slots.
- 9. The electrical connector of claim 7 wherein the insulative housing comprises a first piece and a second piece, with the second piece slidably engaged to the first piece.
- 10. An electrical connector of the type that includes at least two connector pieces that mate in a mating plane, comprises:a) a first connector having: i) a first housing, ii) a first plurality of wafers held in parallel, each containing a plurality of right angle signal conductors having mating contact portions, and an insulative body holding the signal conductor with the mating contact portions held in a line in the mating plane, with the insulative body of each wafer connected to the first housing, iii) a first plurality of right angle power conductors, wider than the signal conductors, each connected to the first insulative housing; b) a second connector, adapted to mate to the first connector, comprising: i) a second housing ii) a second plurality of wafers held in parallel, each containing a plurality of right angle signal conductors having mating contact portions, and an insulative body holding the signal conductors, with the insulative body of each wafer connected to the second housing, and iii) a plurality of power wafers, each containing a plurality of right angle power conductors, wider than the signal contacts, and an insulative body holding a group of the right angle power conductors.
- 11. The electrical connector of claim 10 used in an electronic system having a first printed circuit board having a forward edge, with a plurality first connectors mounted along the forward edge of the first printed circuit board and a plurality of orthogonal printed circuit boards, each having a forward edge disposed orthogonal to the forward edge of the first printed circuit board, each such orthogonal board having a second connector mounted along its forward edge engaging one of the first connectors on the first printed circuit board.
- 12. The electrical connector of claim 10 wherein the first connector additionally comprises a cap, compliantly coupled to the first housing, wherein the mating contact portions of the signal conductors of the first plurality of wafers and the first plurality of right angle power conductors are secured to the cap, and wherein the signal conductors of the first plurality of wafers and the first plurality of right angle power conductors each include a portion secured to the first housing and include a compliant portion between the secured portion and the mating contact portion.
US Referenced Citations (11)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 337 034 |
Oct 1989 |
EP |