Note: Descriptions are shown in the official language in which they were submitted.
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Field of the Invention
The invention relates to a connector for connecting a
daughter printed circuit board (PCB) to a backplane.
Background of the Invention
Backplanes are printed circuit boards or metal plates on
the upper sides of which "daughter" PCB's are detachably mounted
perpendicularly to the backplanes for easy removal. One way of
electrically connecting a daughter board to another daughter board,
the backplane, and other circuitry is by a two-piece multiple-
contact connector consisting of a first connector element that
is attached to the backplane and a mating second connector element
that is attached to the daughter board and fits between upwardly
extending sidewalls of the first element. When the two elements
are joined, a plurality of rows of contact posts directed upwardly
between the sidewalls of the first element are connected to a
plurality of corresponding downwardly directed forked contacts of
the second element.
Summary of the Invention
According to the present invention there is provided a
daughter printer circuit board and backplane assembly comprising
a backplane, a plurality of daughter printed circuit boards mounted
perpendicular to the backplane, a plurality of first connector
elements connected to the backplane, each first connector element
including a base of insulating material, a pair of first elongated
flat sidewalls of insulating material extending from the base per-
pendicular to the base and parallel to the daughter boards and to
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each other and spaced from each other to define a contact region
~ac~s
between their inwardly directed ~ts, the contact region being
free of insulating material of the first connector element, and a
plurality of rows of free standing first contacts extending from
the base parallel to the sidewalls along first axes between and
parallel to the first sidewalls and the base, a plurality of second
connector elements connected to the daughter boards, each
second connector element including a housing of insulating material
having outwardly directed second sidewalls facing and fitted be-
tween the first sidewalls and a plurality of second contacts
therein arranged in rows along second axes between and parallel to
the first and second sidewalls and having contacting ends aligned
with and contacting the first contacts of a respective first
connector element and daughter board connection ends connected to
the daughter board in rows, the first and second connector elements
having first and second ends, at least one of the ends being close
to the closest contacts to facilitate close spacing between con-
tacts on adjacent connector elements brought close enough to abut
each other, and a metal stiffener having one end engaging the
housing of insulating material and another end extending above and
over the housing and the second contacts and secured to the
daughter board, the one end compressing the insulator housing
between it and the daughter board, the metal stiffener extending
along the bottom of the daughter board.
The following is a description, by way of example, of an
embodiment of the present invention, reference being had to the
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accompanying drawings in which:-
Figure 1 is a perspective view of a connector for connec-
ting a daughter printed circuit board to a backplane according to
the invention.
Figure 2 is a vertical sectional view, taken at 2-2 of
Figure 1, of the Figure 1 connector.
Figure 3 is an exploded diagrammatic perspective view
showing a contact of a daughter board connector element of the
Figure 1 connector and the portion of the daughter board connector
element on which the contact is carried.
Figure 4 is an exploded perspective view showing a con-
tact of a backplane connector element of the Figure 1 connector
prior to placement in grooves of sidewalls of a backplane connector
element of the Figure 1 connector.
Figure 5 is a vertical sectional view, taken at 5-5 of
Figure 1, showing mating of contacts of the Figure 1 connector in
use.
Structure
Referring to Figure 1, there is shown two-piece connec-
tor 10 for electrically connecting daughter printed circuit board
12 (shown diagrammatically without any electronic components) to
backplane 14. Connector 10 includes lower backplane connector
element 16 connected to backplane 14 and upper daughter board
connector element 20 connected to daughter board 12~ Secured to
backplane 14 and passing upwardly through backplane connector ele-
ment 16 are four rows of signal contact pins 18 for mating with a
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corresponding plurality of forked signal contacts 22 mounted in
housing 24 (Figure 2).
Referring to Figures 2, 3 and 5, signal contacts 22 of
daughter board connector element 20 are forked at lower ends 26 in
boxes 28 of plastic housing 24 and extend upwardly and are bent
horizontally. The other ends 23 of contacts 22 pass through plas-
tic guide board 30 and holes in daughter board 12, where they are
soldered (Figure 5). Aluminum stiffener 32 is connected between
guide board 30 and housing 24 to cover exposed portions of contacts
22 and provide structure to daughter board connector element 20.
On an outer face of sidewall 34 of housing 24 are ground contacts
36, shown isolated from housing 24 and in more detail in Figure
3. Contacts 36 are secured to wall 34 of housing 24 via vertical
tabs 37, secured in place during molding of housing 24, and hori-
zontal tabs 39, bent upward after molding. The lower ends of
contacts 36 are inclined to provide guide surfaces 40. Laterally
extending prongs 38 of contacts 36 pass through holes in daughter
board 12, where they are soldered (Figure 5). Contacts 36 are
approximately 0.008 inch thick and are made of phosphor bronze with
100 microinches of nickel covered by 20 microinches of plated
gold.
Referring to Figures 2, 4 and 5, it is seen that signal
contact pins 18 of backplane connector element 16 are press flt
in backplane 14, and that backplane connector element 16 has side-
wall contacts 42 provided in grooves 44 of right-hand sidewall
46 extending upward from base 47. Each contact 42 has three
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contact portio~s 50 that extend upward from connecting portion
53 through holes 51 to grooves 44. Adjacent to the top of base
47, contact portions 50 bend away from contact region or cavity 54
between sidewalls 46, 56 to fulcrum portion 52. From there they
bend back toward and into contac~ region 54, and at contact points
48 they begin to bend back away from region S4. At the upper
movable end of each contact portion 50 is tab 58, which extends
laterally behind overhanging portion 60 of sidewall 46. Recess
45 extends further into sidewall 46 at the top of groove 44. Con-
tacts 42 are made of a copper alloy (C72500) and have a welded
inlay at contact areas 48 (Figure 4) of 100 microinches of nickel
covered by 100 microinches of sold.
Operation
In use, backplane connector element 16 is connected to
backplane 14 by inserting the lower press-fit portions of contact
pins 18 and contacts 42 through holes in the backplane. Daughter
board connector element 20 is connected to daughter board 12 by
screw 64 through guide board 30 and stiffener 32 and also by solder
where ends 23 of contacts 22 and prongs 38 of contacts 36 pass
through holes 62 in daughter board 12. Contacts 18, 22 are used
to carry signals, while contacts 36, 42 are used to carry ground.
Before insertion of daughter board connector element 20
into contact region 54, tabs 58 bear against overhanging portions
60, owing to preloading forces, and precisely locate the contact
points 48 so that they do not extend into contact region 54 so far
that there would be jamming during insertion. When daughter board
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connector element 20 is inserted into contact region 54, contact
pins 18 are received between forked prongs 26; the upper ends of
contacts 42 are bent back slightly by inclined surface 39 and
received in recesses 45, and contacts 36 touch contact points 48
of contacts 42, as is shown in Figure 5. Recesses 45 are provided
so that contact portions 50 are only bent at the lower ends to
prevent the very large insertion forces that would be required if
contact portions 50 were supported at two ends.
In addition to providing ground connections without
taking up any extra space on connector 10, a further advantage is
that ground contact prongs 38 can be provided on daughter boards
12 immediately adjacent to a row of signal contacts 22 to provide
a short ground path to permit high-speed switching.
Other Embodiments
Other embodiments of the invention are within the scope
of the following claims.
