Note: Descriptions are shown in the official language in which they were submitted.
CA 02348241 2001-05-18
Docket No. WI 99-12
HIGH CURRENT BOARD-TO-BOARD
POWER CONNECTOR
Related Application
The present application claims priority of U.S. Provisional Application
Serial No. 60/205,252, filed May 19, 2000, entitled "HIGH CURRENT BOARD
TO-BOARD POWER CONNECTOR", the disclosure of which is incorporated by
reference herein in its entirety.
Field of the Invention
The present invention relates generally to electrical connectors, and more
particularly, to electrical power connectors. Advantageously, the present
invention can be used to carry high current from one circuit board to another
circuit board.
Background of the Invention
Electrical power connectors are often needed to carry high current
between one circuit board and another circuit board. Electrical backplanes
frequently have multiple daughtercards connected to the backplane which
require
I S both signal and power connectors to make electrical connections between
the
backplane and daughtercard. For example, a need exists in the art for a
connector
capable of carrying 400 amps at various voltages.
Electrical backplanes frequently are populated with multiple
daughtercards. The daughtercards are connected to the backplanes using
electrical connectors known in the art. From time to time it becomes desirable
or
necessary to change daughtercards to either change the configuration of the
electrical circuit contained on the daughtercard or to replace defective
CA 02348241 2001-05-18
2
daughtercards. The prior art does not adequately address a simple means for
providing high current power at low voltages to the daughtercard from power
supplies contained on the backplane. In addition, it would be desirable to
have an
electrical connector for providing power to a daughtercard from a backplane in
which the power connection between the backplane and the daughtercard is
effected simultaneously with inserting the daughtercard into the electrical
connector which transfers electrical signals between the backplane and
daughtercard.
Summary of the Invention
It is, therefore, an object of the present invention to provide an electrical
power connector capable of carrying 400 amps at various voltages.
Another object of the present invention is to provide a electrical power
connector having a non-conductive sheath and tip thereby reducing the
likelihood
of a service technician accidentally becoming electrified.
Another object of the present invention is to provide an electrical
conductor using a plurality of leaf springs for carrying current between a
male and
female connector.
Yet another object of the present invention is to provide an electrical
power connector for providing power from an electrical backplane to one or
more
daughtercards mounted on the backplane.
The present invention is directed to a high current electrical power
connector for electrically connecting two circuit boards, such as a backplane
and a
daughtercard. Advantageously, the backplane connector includes a non-
conductive tip and sheath to reduce the likelihood of a service technician
accidentally becoming electrified.
These and other objects of the present invention are achieved by an
electrical power connector, including a body including a first portion with a
first
plurality of undercut grooves and a second portion having a second plurality
of
CA 02348241 2001-05-18
3
rectangular slots. A first plurality of spring contacts are each positioned in
a
corresponding one of the first plurality of undercut grooves. A second
plurality of
pins are each positioned in a corresponding one of the second plurality of
rectangular slots.
Still other objects and advantages of the present invention will become
readily apparent to those skilled in the art from the following detailed
description,
wherein the preferred embodiments of the invention are shown and described,
simply by way of illustration of the best mode contemplated of carrying out
the
invention. As will be realized, the invention is capable of other and
different
embodiments, and its several details are capable of modifications in various
obvious respects, all without departing from the invention. Accordingly, the
drawings and description thereof are to be regarded as illustrative in nature,
and
not as restrictive.
Brief Description of the Drawings
The present invention is illustrated by way of example, and not by
limitation, in the figures of the accompanying drawings, wherein elements
having
the same reference numeral designations represent like elements throughout and
wherein:
Figure 1 is a perspective view of a backplane connector according to the
present invention;
Figure 2 is a perspective view of a daughtercard connector according to
the present invention;
Figure 3 is a perspective view of the daughtercard connector of Figure 1
with a protective sheathing covering the male portion of the backplane
connector;
Figures 4A, 4B and 4C are side, top and right elevational views of an
assembled electrical power connector according to the present invention;
CA 02348241 2001-05-18
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Figures SA and 5B are top and bottom perspective views of a spring
contact according to the present invention; and
Figure 6 is a partial cross-sectional illustration depicting the backplane
connector engaged with the daughtercard connector.
Best Mode for Carrying Out the Invention
Referring first to Figure 1, a backplane connector, generally indicated at
20, includes a backplane connecting base 24 and a male portion 22 for
connecting
to a daughtercard. The backplane connecting base 24 and the male portion 22
are
both preferably manufactured from aluminum, brass, copper, a copper alloy or
any other electrically conductive material. The male portion 22 is at right
angles
relative to the backplane connecting base 24 and is located at one end thereof
to
form an L-shaped backplane connector 20. The backplane connecting base 24 has
a 1 inch width and has an 8 x 20 pin array for a total of 160 pins. The male
portion 22 also has a one inch width. The pins 28 may be C-press~ contacts
which are on a lower surface 26 of the backplane connecting base 24. The C-
Press pins which may be used to mount the connector to the backplane are
described in U.S. Patent No. 4,017,143, issued April 12, 1977 and a power
connector using such pins as described in U.S. Patent No. 5,842,876, issued
December l, 1998, both of which are hereby incorporated by reference in their
entirety into this specification. A row of pins 40 are stamped from a unitary
piece
of metal. The pins 40 are connected to each other by a common carrier (not
shown). The carrier is inserted into a groove machined into the bottom surface
of
the base member 26. A staking process is used to mechanically fasten the
carrier
and the pins 40 to the base member 26. A soldering, brazing or other
mechanical
fastening process can be used.
The number of contacts in the backplane connecting base 24 is a function
of the amount of power to be transferred. Also, the size of the contacts and
their
respective mounting holes can be varied to increase or decrease the amount of
CA 02348241 2001-05-18
power transferred between the backplane and power connector. Note also that
the
mounting pins 28 can either be press fit into plated holes in the respective
backplane and daughtercard or soldered into the holes to effect secure
mechanical
and electrical connections between the backplane and connector.
5 It should be understood that although the connectors are depicted in
Figures 1-4 in a horizontal position, the electrical connector 20 according to
the
present invention is usable in any orientation.
It should be appreciated that the electrical power connector shown and
described can assist in providing physical mounting rigidity between the
backplane and daughtercards and that multiple power connectors can be used for
one or more daughtercards mounted on a backplane depending on the amount of
power required for the daughtercard and to assist in providing mechanical
rigidity
between the backplane and daughtercard.
The male portion 22 has outer walls 30, 32. The outer wall 30 has a
plurality of undercut grooves 40, 42, 44, 46, although any number of grooves
can
be used. The outer wall 32 has undercut grooves 50, 52, 54, 56. These grooves
40-46 and 50-56 extend across the entire width of the board 22. The undercut
grooves 60, 62, 64 and 70, 72, 74 do not have to extend for the entire length
of the
walls 22, 24, respectively. For example, the grooves 60, 62, 64 and 70, 72, 74
can
stop short of the end of one wall to provide a positive stop to help to retain
the
springs to the walls. The backplane connecting base 24 and the male portion 22
are joined together at one end 26 of base 24 on an opposite side thereof from
pins
28 by a dovetail joint 60. As depicted, the female dovetail joint 62 is formed
in
male portion 22 and a mating male dovetail 64 is formed at one end of male
portion 22.
On an opposite and distal end of the male portion 22 is an insulating
member 70 having a pair of inclined surfaces 72, 74 joined by a curved surface
76
to facilitate insertion of the daughtercard connecting member into a
connecting
member on the daughtercard as described below. The member 70 is joined to
CA 02348241 2001-05-18
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male portion 22 using a dovetail joint 78. Insulating member 70 forms an
insulating tip reducing the likelihood of a service technician accidentally
becoming electrified.
The insulating tip material can be any non-conductive plastic that can
operate in the temperature environment for this connector. A plurality of
contact
springs 80-94 are mounted in undercut grooves 40-46 and 50-56, respectively.
Contact springs 80-94 extend outwardly beyond outer surfaces 30, 32 as
explained in greater detail below. Each contact spring 80-94 includes a
plurality
of contact surfaces. Although leaf springs are shown, other types of contacts
can
be used, for example, a cantilevered contact having a free end to make contact
with the mating daughtercard connector. It is desirable to have roughly the
same
number of contact surfaces on each of the contact springs 80-94 to equal the
number of pins 28. Equal number of contacts are required to share in
conducting
the current from one connector to the other without creating hot spots if the
balance is not maintained.
Referring now to Figure 2, a daughtercard connector, generally indicated
at 100 is depicted. The daughtercard connector 100 can have its exterior
surfaces
covered with an electrically insulating cover. The daughtercard connector 100
has a hollow female connector portion 110 having a length sufficient to
receive
the male portion 22 of the backplane connector 20. The member 110 is
electrically conductive and is mounted to a contact-carrying base 112. Eight
optional fins 120-134 extend transversely from the contact-carrying base 112
to
help dissipate any undesired heat generated by the connector carrying 400 amps
of current. The heat can be dissipated through conduction and potentially
through
convection. Interior walls 150 of the daughtercard connector 100 are
electrically
conductive sidewalk which are contacted by the springs 80-94 of the male
portion.
Figure 3 is similar to Figure 1 except a non-conductive sheath 200
surrounds the male portion 22 and is substantially co-extensive therewith. The
CA 02348241 2001-05-18
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non-conductive sheath 200 is located at one end of the connector assembly 20
and
has top surfaces having inner sloping top sections 220 to facilitate
intermating of
the connector portions 110. The sheath 200 is held in place by a latching
mechanism. The sidewalk will flex and latch on to under cut in the main body.
A gap is formed between contact springs 80-94 and inner walls of the non-
conductive sheath 200. The non-conductive tip 70 extends above an upper
surface of the sheath 200. The sheath 200 is made from a moldable
thermoplastic
material capable of meeting the temperature and environmental requirements.
As depicted in Figures 4A, 4B and 4C, the daughtercard connector 100 is
inserted into the backplane connector 20 to form a complete power connector
assembly according to the present invention. The female connector 110 mounted
on the daughtercard 100 is inserted into the sheath 200 such that the hollow
member 110 comes into contact with each of the springs 80-94. Advantageously,
the use of the non-conductive sheath 200 and non-conductive tip 70 prevents or
minimizes the likelihood that a service technician will become electrified
during
mating of the connectors 20 and 100.
Figures SA and SB depict a contact spring 300 according to the present
invention. The contact spring 300 is illustrative of the contact springs 80-94
discussed above. The contact springs are preferably formed from beryllium
copper or equivalent material with the appropriate mechanical and electrical
properties and can be stamped in a progressive die. The contact spring 300 has
a
pair of opposed longitudinal sections 300, 302. Joining the longitudinal
sections
are a plurality of spaced apart curved members 310-336 which extend
transversely relative to the longitudinal sections 300, 302. The longitudinal
sections are retained in opposite undercut portions of the undercut grooves.
Each
of these flexible spring contacts 310-336 forms an electrical contact point
between the male connector and the female connector. One benefit of the power
connector design utilizing multiple spring fingers of the type shown is to
effect a
tight electrical and mechanical connection between the two power connector
CA 02348241 2001-05-18
g
portions evens though slight misalignment may occur between the backplane and
daughtercard.
Referring now to Figure 6, the hollow female member 110 is shown
engaged with the male member 22. When the female member is engaged with the
male member as depicted in Figure 6, each of the contact springs 40-46 and 50-
56
is brought into contact with the conductive inner wall of the female member
110.
Each of the spring contacts forms an electrical path between the hollow member
110 and the board 22. It is not necessary to have the same number of C-Press
contacts and spring members.
It should now be appreciated that an electrical power connector capable of
carrying 400 amps at 1-2 volts has been described. Advantageously, the use of
spring contacts simplifies the construction of the power connector. Also, the
use
of an electrically non-conductive sheath and an electrically non-conductive
tip on
the backplane connecting board minimize or reduce the likelihood of the a
service
technician being electrified.
Member 400 in Figure 6 insulates the backpanel connector 20. The
daughtercard connector 100 is insulated with a sheath similar to the other
connector.
The power handling capability of the power connector can be modified by
changing either the number of pins on the backplane and daughtercard sides of
the
power connector and/or the size of the pins and the plated through-holes on
the
backplane and daughtercard into which the pins are inserted. Also the wide and
length of the base member 24 and corresponding daughtercard portion 112 can be
sized to accommodate different numbers, pins and contacts and voltages and
currents. The pins can either be placed in the backplane and daughtercard by
friction fit into plated through-holes in the respective boards and/or can be
soldered in place to effect a secure mechanical and electrical connection
between
circuits on the backplane and daughtercard through respective power connector
portions.
CA 02348241 2001-05-18
9
It will be readily seen by one of ordinary skill in the art that the present
invention fulfills all of the objects set forth above. After reading the
foregoing
specification, one of ordinary skill will be able to affect various changes,
substitutions of equivalents and various other aspects of the invention as
broadly
disclosed herein. It is therefore intended that the protection granted hereon
be
limited only by the definition contained in the appended claims and
equivalents
thereof.
