U.S. patent number 3,923,361 [Application Number 05/503,216] was granted by the patent office on 1975-12-02 for electrical connector and circuit board mounting system.
This patent grant is currently assigned to Sanders Associates, Inc.. Invention is credited to Harold Rosen.
United States Patent |
3,923,361 |
Rosen |
December 2, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Electrical connector and circuit board mounting system
Abstract
A zero initial insertion and full zero retraction force
connector is provided including a housing and a folded leaf spring
inserted into the housing. The leaf spring has various portions
defining a pin, a socket, and a spring member. The spring 5 member
extends from one side of the socket above the housing and is
anchored in the housing at its free end. Depression of the spring
member when two connectors mate causes one wall of the socket to
move towards an opposing wall thereby to make stable electrical and
mechanical contact with an inserted pin during the last portion of
the insertion stroke in which the pin is inserted into the
socket.
Inventors: |
Rosen; Harold (Nashua, NH) |
Assignee: |
Sanders Associates, Inc.
(Nashua, NH)
|
Family
ID: |
24001188 |
Appl.
No.: |
05/503,216 |
Filed: |
September 5, 1974 |
Current U.S.
Class: |
439/264;
439/848 |
Current CPC
Class: |
H01R
12/82 (20130101) |
Current International
Class: |
H01R
12/16 (20060101); H01R 12/00 (20060101); H01R
013/28 () |
Field of
Search: |
;339/17,32,33,47-49,75,176,258 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
433,046 |
|
Aug 1935 |
|
UK |
|
22,981 |
|
Sep 1969 |
|
JA |
|
Primary Examiner: McGlynn; Joseph H.
Attorney, Agent or Firm: Etlinger; Louis Tendler; Robert
K.
Claims
I claim:
1. An electrical connector comprising: a housing and an
electrically conductive spring member, said spring member folded on
itself to provide a pin and separated from itself to form a socket,
one portion of the spring member forming a laterally deflectible
wall of said socket and including an extension having a bent
portion, said spring member being mounted in said housing with said
pin extending from one surface of said housing, said bent portion
extending above a second surface of said housing and means for
deflecting said one portion upon towards an opposite wall of said
socket upon depression of said bent portion.
2. The connector of claim 1 wherein said folded portion includes
two spring portions fixedly attached one to the other.
3. The connector of claim 1 wherein said housing is made from a
solid block of material having a vertical channel with narrow and
widened portions communicating with opposing surfaces of said
block, and a horizontal channel
4. The conductor of claim 1 wherein said extension extends
substantially at right angles to said one spring portion.
5. The connector of claim 4 wherein said extension includes a
further radiused portion between said bent portion and said one
spring portion.
6. The connector of claim 4 wherein said bent portion is
radiused.
7. The connector of claim 6 wherein the angle subtended by said
radiused bent portion is 90.degree..
8. An electrical connector comprising a housing, a spring member
folded on itself to provide a pin and separated from itself above
the folded portion to form a socket, one portion of the spring
member forming a wall of said socket, being deflectable towards an
opposite wall, said spring portion including an extension having a
bent portion, said spring member being mounted in said housing with
said pin extending from a face of said housing and said bent
portion extending above another face of said housing, the free end
of said bent portion being fixedly attached to said housing, and
means for deflecting said one portion responsive to depression of
said bent portion.
9. The connector of claim 8 wherein the folded portion of said
spring member includes two spring portions fixedly attached one to
the other.
10. The connector of claim 8 wherein said housing is made from a
solid block of material having a vertical channel with narrow and
widened portions communicating with opposing surfaces of said
block, and a horizontal channel communicating with the widened
portion of said vertical channel and one of said opposing surfaces,
said spring member being inserted into said channels.
11. The connector of claim 8 wherein said extension extends
substantially at right angles to said one spring portion.
12. The connector of claim 11 wherein said extension includes a
further radiused portion between said bent portion and said one
spring portion.
13. The connector of claim 11 wherein said bent portion is
radiused.
14. The connector of claim 13 wherein the angle subtended by said
radiused bent portion is 90.degree..
15. A hermaphroditic zero initial insertion and zero retraction
force connector comprising:
a housing; and,
an electrically conductive spring member having a portion folded on
itself, two additional portions of said spring member being spaced
apart to form a socket above said folded portion, said spring
member mounted in said housing with a portion of said folded
portion extending exteriorally of said housing from one surface
thereof, one of said two additional portions forming a deflectible
beam, said deflectible beam including a further spring portion
extending from said deflectible beam at substantially right angles
thereto, said further portion including bent portion means
extending above another surface of said housing for deflecting said
deflectible beam upon depression of said bent portion means, said
further portion being fixedly attached to said housing at a point
to the side of said bent portion away from said deflectible
beam.
16. The connector of claim 15 wherein said folded portion includes
two spring portions fixedly attached one to the other.
17. The connector of claim 15 wherein said housing is made from a
solid block of material having a vertical channel with narrow and
widened portions communicating with opposing surfaces of said
block, and a horizontal channel communicating with the widened
portion of said vertical channel, said spring member being inserted
into said channels.
18. The connector of claim 15 wherein said bent portion is
radiused.
19. The connector of claim 18 wherein the angle subtended by said
radiused bent portion is 90.degree..
20. The connector of claim 19 wherein said extension includes a
further radiused portion between said bent portion and said one
spring portion.
21. A method of mounting printing circuit boards comprising
sandwiching said boards between electrical connectors having pins
extending from one surface and sockets exposed at an opposing
surface, said sockets adapted to receive pins projecting through an
intermediate printed circuit board from a connector immediately
thereabove, said connectors comprising a housing and a spring
member folded on itself to provide a pin and separated from itself
above the folded portion to form a socket, one portion of the
spring member forming a wall of said socket being deflectible
towards an opposite wall, said one portion including an extension
having a bent portion, said spring member being mounted in said
housing with said pin extending from a face of said housing and
said bent portion extending above another face of said housing, the
free end of said bent portion being fixedly attached to said
housing, and means for deflecting said one portion responsive to
depression of said bent portion, and
depressing the bent portions of the connector by clamping the
sandwiched boards and connectors together to secure mating pins and
sockets.
22. A method of releaseably interconnecting printed circuit boards
comprising
providing each printed circuit board with a hermaphoditic
electrical connector at opposite ends of said printed circuit
board, each of said connectors having a pin extending from one
surface and a socket exposed at an opposite surface, each of said
pins being electrically connected to selected conductors on the
printed circuit board on which the connector is mounted; and
stacking said circuit boards carrying said connectors one on top of
the other such that pins extending through a circuit board are
inserted into corresponding sockets of a connector mounted on a
next adjacent circuit board whereby a vertical sandwich structure
of interconnected boards is formed, said hermaphoditic electrical
connector comprising a housing and a spring member folded on itself
to provide a pin and separated from itself above the folded portion
to form a socket, one portion of the spring member forming a wall
of said socket being deflectable towards an opposite wall, said one
portion including an extension having a bent portion, said spring
member being mounted in said housing with said pin extending from a
face of said housing and said bent portion extending above another
face of said housing, the free end of said bent portion being
fixedly attached to said housing, and means for deflecting said one
portion responsive to depression of said bent portion, and
depressing the bent portions of the connectors by clamping the
stacked boards and connectors together to secure mating pins and
sockets.
23. In combination
a printed circuit board having conductive layers thereon, and
an electrical connector mounted at one end thereof, said connector
comprising a housing and an electrically conductive spring member,
said spring member folded on itself to provide a pin and separated
from itself above the folded portion to form a socket, said spring
member being mounted in said housing such that said pin extends
from one surface of said housing and such that said socket
communicates with an opposing surface of said housing, one portion
of the spring member forming a wall of said socket being
deflectable towards an opposite wall, said one portion including an
extension having a bent portion, the free end of said bent portion
being fixedly attached to said housing, and means for deflecting
said one portion responsive to depression of said bent portion.
24. The combination of claim 23 wherein said connector is mounted
with said pin extending in a direction parallel to the plane of
said circuit board.
25. The combination of claim 23 wherein said connector is mounted
with said pin extending through said circuit board.
26. The combination of claim 25 wherein said pin is connected to
one of said conductive layers at the point at which said pin
extends through said circuit board.
27. The combination of claim 25 and including means for connecting
said pin to a selected conductive layer on said circuit board and
further including a number of board-connector combinations stacked
one on top of the other with a pin from one circuit board extending
into a socket of a connector on a circuit board immediately
thereunder.
28. The combination of claim 27 wherein one of the spring members
forming a wall of said socket includes an extension having a bent
portion, said spring member being mounted such that said bent
portion extends above said opposing surface and is adapted to coact
with the bottom of a circuit board immediately thereabove to
deflect said one spring member into contact with the pin from the
circuit board immediately thereabove.
29. The combination of claim 28 wherein a number of pins extend
from each circuit board, whereby release of one circuit
board-connector combination from an adjacent circuit
board-connector combination is easily effected.
30. In combination
a hermaphroditic electrical connector of the type comprising: a
housing and an electrically conductive spring member, said spring
member folded on itself to provide a pin and separated from itself
to form a socket, one portion of the spring member forming a
deflectible wall of said socket and including and extension having
a bent portion, said spring member being mounted in said housing
such that said pin extends from one surface of said housing, and
such that said bent portion extends above a second surface of said
housing, said bent portion including means for deflecting said
deflectible wall towards an opposite wall of said socket upon
depression of said bent portion;
a body having a connector post depending therefrom and adapted to
be inserted into the socket of said connector, said body having a
surface adapted to coact with the bent portion of said connector to
depress it when the housing of said connector and said body are
forced together; and
means for maintaining said housing and body forced together thereby
to deflect said one spring portion into contact with said post.
Description
This invention relates to electrical connectors and more
particularly to a zero initial insertion and full zero retraction
force connector.
One of the most important problems associated with multi-pin
electrical connectors is the problem of the force necessary to
cause the mating of the male and female portions of the connector
and the separation of these portions. It will be appreciated that
if 2 ounces of force is required to insert each pin, for connectors
having upwards of 200 pins the mating force is indeed considerable.
Moreover, and perhaps more importantly, when the connections are
pulled apart a large force is necessary to separate the two
portions of the connector. The insertion and retraction problem
associated with multi-pin connectors is particularly severe in the
interconnection of printed circuit boards and cables having a large
number of conductors. The subject invention solves this problem by
providing that the force applied to a pin from one connector
inserted into the socket of a mating connector be zero minimized
during the mating and separation of the connectors.
The problem of the force necessary to connect and disconnect mating
conductors centers around not only the convenience factor but also
around the necessity for preventing the buckling of the pins. In
high density packaging configurations it is desirable to make the
connector pins thin. However, the pins oftentimes buckle when
inserted. The subject invention solves the buckling problem by
restricting the compressive or buckling forces on the pin to occur
during only the last few mills of the insertion stroke, thereby
effectively applying the buckling force to the extremely short
uninserted pin section remaining. This totally eliminates pin
buckling as a source of failure while additionally retaining the
wipe action necessary for self-cleaning. Moreover, pin damage often
occurs due to the jerk, or sudden relaxation of force upon
separation. The subject connector described hereinafter also
eliminates this potential for damage by quick release of the pin
during separation.
By way of background, as described in connection with U.S. Pat. No.
3,474,387, prior art connectors generally utilize contacts which
are in the form of deflectable simple beams in the female portion
of the connector which are deflected into contact with the pins or
posts from a mating male connector. The deflection of the simple
beam is ordinarily accomplished by a cam eccentrically mounted
relative to the center line of the connector and rotatable about an
axis normal to the plane within which the beams are deflectable. As
noted in the above mentioned patent, one of the major difficulties
with the external cam actuated connector is that access to the cam
is oftentimes approached from the lengthwise end of the connector
instead of being accessable from the same direction in which the
force is applied to cause mating of the male and female portions of
the connector. In the case of printed circuit boards what this
means is that when the circuit board is inserted it is necessary to
actuate the cam from a direction which may be obscurred by either
the walls of the cavity into which the circuit board is inserted or
by other equipment or electronic components. Thus there is no easy
access to the cam actuating member for either camming the
deflectable beams into contact with the projecting pins or, for
camming them away from the pins in the case of removal of the
printed circuit board.
In the above mentioned patent, there is illustrated a two-part
connector in which vertically mounted spring members are cammed
into contact with a portion of the circuit board containing the
contact pads. It will be appreciated that this connector is a
two-part connector in which a camming member contacts a spring
member in order to urge it into contact with an adjacent male
contact when the two portions of the connectors are squeezed
together. What in effect has been provided therefore is a separate
camming member. Moreover, the connector of this patent is not a
hermaphroditic connector in the sense that in hermaphoditic
connectors the same connector assembly is used as a male and female
member.
Perhaps more importantly the thickness of the spring member in the
above mentioned patent is such as to require a large amount of
force in order to bring the spring member into contact with a
contact pad on the inserted printed circuit board. The force
necessary to make contact is dependent on the elasticity of the
spring member which in turn is dependent at least in part on the
thickness of the spring. It will be appreciated that the same
spring member which is deflected to make contact with the inserted
contact pad also extends outwardly of the connector to provide a
contact pin or post. It is important for the structural stability
of the pin that it be of sufficient thickness to withstand
buckling. Since the deflected member and the pin are made from the
same piece of metal, the resulting spring member in the connector
housing is relatively stiff. This in turn results in the necessity
of applying a relatively high force in order to deflect the spring
member into contact with an inserted conductor. While this force
may not be excessive in the case of one or two pins, the force is
multiplied by the number of pins and therefore becomes a
considerable problem when, for instance, 200 or more pins are
provided.
The force necessary to deflect the spring member is also important
when considering wear and reliability. This problem can perhaps be
more readily appreciated by referring to U.S. Pat. No. 3,750,085.
In this patent a spring is deflected into contact with an inserted
conductor by the squeezing together of two parts of the connector.
In this patent the spring member and pin are also from the same
piece of metal. As before, the force necessary is directly related
to the thickness of the spring member. When this force is excessive
the point of contact between the end of the spring and the upper
portion of the connector causes the spring to dig into the upper
portion of the connector thus weakening it and/or scoring it by an
amount directly proportional to the force necessary to establish
the requisite contact force. In this connection, it will be
appreciated that a thinner spring member would dig in less during
the mating procedure and reliability would be improved.
The aforementioned problems are solved by the subject electrical
connector which, because of its folded spring configuration,
requires approximately one-fourth the force normally used to
establish the requisite contact force. The folded construction also
provides a thick pin depending from the connector body which is
integral to and is a part of the deflectable spring member. Because
of the folding of the spring to form the pin, the pin is rigid and
resists buckling while the spring portion, being only one-half the
thickness of the pin is relatively easy to deflect and therefore
requires less in the way of deflection force. The connector is also
unitary in construction in the sense that it is not a two-part
connector; it is hermaphroditic in the sense that the same
connector is utilized both as a male and female member; and it is
an initial zero insertion force and a full zero retraction force
connector which permits easy insertion and extraction.
In one embodiment, the subject connector includes a housing having
a horizontal channel in its upper face. A vertical channel extends
through the body of the connector and communicates both with one
end of the horizontal channel and with the bottom face of the
connector housing. Within the horizontal and vertical channels is
placed a folded leaf spring structure. The vertical channel has a
wider upper portion and the folded leaf spring which projects down
through the lower portion to form the pin of the connector is
separated in this widened portion. One half of the leaf spring is
stationary and rests against a sidewall of the widened portion. The
other separated portion of the leaf spring ordinarily resides
against an opposing vertical wall of the widened portion and is
adapted to move into contact with an inserted pin when the bottom
of a similarly constructed connector body impinges upon a portion
of this leaf spring which projects above the top of the connector
body through the upper channel. When the projecting portion of the
spring is flattened, the laterally displaceable portion of the leaf
spring within the vertical widened channel is pressed into contact
with the downwardly depending pin from the connector immediately
above.
During the first part of the insertion of a pin into the female
socket portion of the connector the pin is free and no electrical
or mechanical contact is made. During the last few mills of
insertion the pin wipes against the socket as mechanical connection
is made which results in a cleaning action. It will be appreciated
that during the majority of the insertion stroke no force or load
is applied to the pin, while during the last few mills of
insertion, since force is necessary to make both the electrical and
mechanical connection, the pin is loaded. Thus the term "zero
initial insertion force" refers to a lack of force during the
initial insertion of the pin. Since a load is only applied to the
pin after the pin is almost fully inserted, pin buckling is
minimized because the load is applied close to the base of the
inserted pin where the lever arm is shortest and the mechanical
stability is highest.
In this connector, there is no two-part body construction and there
is no separate camming surface to urge the leaf spring into contact
with an adjacent inserted conductor. Rather, the portion of the
leaf spring projecting above the connector body, having been urged
in a downward direction causes a translation of the laterally
displaceable portion of the leaf spring into contact with the
inserted conductor post. Final electrical and mechanical connection
is maintained by the clamping together of the two adjacent
connector housings. It will be appreciated therefore that the
connector is of extremely simple construction in which a leaf
spring is folded on itself along one portion and is separated from
itself at another portion. Actuation takes place by flattening a
portion of the spring extending above its housing. The leaf spring
is easily formed and is also easily inserted into the conductor
body to form the aforementioned unitary hermaphroditic
connector.
The resulting electrical connector has a projecting pin, which is
double the thickness of the leaf spring. This, plus the fact that
the load is applied to the pin close to its base only after almost
complete insertion provides for anti-buckling protection. At the
same time only one-half the thickness of the projecting pin or post
is utilized in the leaf spring portion of the connector. This
provides that only one-fourth of the force ordinarily necessary is
exerted in achieving full contact pressure.
In operation, the laterally displaceable portion of the leaf spring
resides against one wall of the vertical channel thereby to give
clearance for the inserted pin from an adjacent connector without
any frictional force being applied to this pin. As the pin is
inserted further into the connector the bottom portion of the
connector body from which the pin depends presses against the
extending spring portion which projects upwardly above the top
surface of the bottom connector. When the pin is near fully
inserted, the bottom of the upper connector depresses the upwardly
extending spring portion thereby to laterally displace the leaf
spring member into contact with the inserted pin to make the
electrical connection. The mechanical connection is completed by
clamping together the two connectors. Removal is quite simple since
release of the two connectors results in a upward force being
applied to the upper connector by the depressed leaf spring from
the lower connector. This force initially aids in the separation of
the connectors. After a predetermined separation the pin is
completely free of frictional engagement with the lower connector
leaf spring and is thereafter easily withdrawn. Thus, the
compressed spring functions to aid in the removal of the upper
connector unlike the two-part connectors of the prior art.
The particular hermaphroditic configuration also makes possible a
new method of interconnecting printed circuit boards. In the usual
configuration, printed circuit boards have end connectors which
mate with rackmounted connectors when the board is inserted into
place. This arrangement requires a separate rack mounted connector
strip which increases the weight of the apparatus.
With the subject connector, printed circuit boards may be
interconnected in a stacked arrangement without the use of separate
rack mounted connectors. This results not only in weight reduction
but also in a mechanically stable selfsupporting package.
It is therefore an object of this invention to provide a
hermaphroditic zero initial insertion and full zero retraction
force electrical connector of unitary construction;
It is another object of this invention to provide an electrical
connector in which the insertion force necessary to provide
sufficient contact engagement force is minimized.
It is yet another object of this invention to provide a low cost
multipin connector comprised of only a housing and a spring having
a folded configuration.
It is a further object of this invention to provide a connector
system utilizing hermaphroditic components in which each component
carries a folded leaf spring having a portion thereof extending
above a surface of the component such that communication between
the surface of one component and the extended spring portion upon
mating of the connector components results in the displacement of a
portion of the spring in a direction orthogonical to the applied
force.
It is a further object of this invention to provide a zero initial
insertion and full zero retraction force electrical connector in
which no separate camming member is utilized.
It is a yet still further object of this invention to provide an
improved method and apparatus for interconnecting printed circuit
boards which reduces the weight of the connected configuration by
eliminating the necessity for a card rack.
It is a yet still further object of this invention to provide a
zero initial and full zero retraction force electrical connector
which is more reliable and less prone to failure.
It is a yet still further object of this invention to provide a
hermaphroditic zero initial insertion and full zero retraction
force electrical connector having the pin and socket member being
formed from the same leaf spring, with the pin portion having
double the thickness of the socket portion thereby to prevent
buckling of the pin while allowing increased flexability of
portions of the socket which is actuated into frictional contact
with a mating male member.
These and other objects of this invention will be better understood
in connection with the following description in view of the
appended drawings in which:
FIG. 1 is a cross sectional and partial perspective view of the
subject connector illustrating a poriton of the connector component
forming the male member inserted into a socket of the component
forming the female member;
FIG. 2 is a partial cross sectional drawing illustrating a portion
of the leaf spring of the connector which extends above the top
surface thereof;
FIG. 3 is a perspective view of printed circuit boards stacked
vertically and connected with the subject connector;
FIG. 4 is a partial sectional and perspective view of the circuit
board and connector illustrated in FIG. 3;
FIG. 5 is a partial exploded view illustrating the method of
replacement of circuit boards and connectors with the configuration
illustrated in FIG. 3;
FIG. 6 is a partial perspective and exploded diagram illustrating
the use of the subject connector in a conventional end-connector
configuration for circuit board applications; and
FIG. 7 is a partial perspective and sectional view illustrating the
subject connectors connected to a circuit board in an end-connector
configuration without the use of additional connecting leads.
Referring now to FIG. 1 a hermaphroditic connector 10 is
illustrated as having a folded leaf spring member 12 inserted into
a vertically extending cavity 14 in connector housing 11. Cavity 14
has a narrow portion 16 and a widened portion generally indicated
at 18. The spring member 12 extends upwardly and outwardly of
cavity 14 and includes separated spring portions 19 and 20 which
ordinarily rest against the walls making up the widened portion 18
of cavity 14. A horizontal portion 21 of spring member 12 projects
outwardly of the connector housing 11.
A second horizontally extending portion 22 of leaf spring member 12
extends to the right in a horizontal channel 24 cut in the top
surface 26 of housing 11. Spring portion 22 includes a bent portion
28 which extends above face 26 of the connector 10. Additionally,
an additional bent portion 30 is provided between spring portions
19 and 28.
Horizontal forces (F.sub.H) generated by spring portion 28 of
spring member 12 is closely approximated by the simple equation set
out hereinafter, ##EQU1##
The vertical force (F.sub.V) is approximated by the following
equation: ##EQU2##
F.sub.H is therefore expressed by: ##EQU3##
A similarly configured connector 36 is located immediately above
connector 10 and has a downwardly depending folded spring portion
forming a pin or post 38 such that connector 36 functions as the
male connector.
As can be seen from FIG. 1 the portion of the spring projecting
through cavity portion 16 is of a double thickness, "2w", as
compared to the thickness of the separated spring portions 19 and
20, e.g. w. As mentioned hereinbefore, the 2w width provides
mechanical stability for the pin while the 37 1w" width of spring
portion 19 provides for increased flexability of this member,
thereby to reduce the force, F.sub.V, necessary in deflecting this
member into contact with an inserted pin or post.
It will be appreciated that spring portion 21 extending outwardly
of the housing, may be provided with any suitable means of making
electric contact thereto such as the threaded screw 40, or a
conductive strip (not shown) continuing along the outside of the
conductor housing to intersect a printed circuit board.
Additionally it will be appreciated that either spring portion 21
or spring portion 22 may be made to extend outwardly of the housing
for convenient connection as desired. In an embodiment to be
described in connection with FIG. 4, there need be no projecting
portion, as the connection to the various spring members is made at
the respective pins.
In operation, connector 36 is moved downwardly with respect to
connector 10 such that pin 38 is inserted between the separated
spring portions 19 and 20. It will be appreciated that there is
provided enough clearance between these spring portions to permit
the insertion of the pin without frictional contact. At a certain
point in the insertion of pin 38 a bottom surface 42 of the
connector 36 impinges upon the top surface of spring portion 28
deflecting it downwardly with a force F.sub.V. The downward
deflection of this spring portion results in the lateral
displacement of spring portion 19 which contacts pin 38 with a
force F.sub.H derived from the previous equations.
It will be appreciated that connectors 10 and 36 may be clamped
together in any convenient manner thereby to form a stable
electrical and mechanical contact between spring member 12 and pin
38. Removal or separation of the two connectors is accomplished by
removing the aforementioned clamping means such that spring portion
19 returns to its initial rest condition along side the wall of the
widened portion 18.
Because of the folded configuration of the spring member 12
approximately one-fourth of the force, F.sub.V, is necessary to
create a predetermined contact force as compared to connectors in
which the bendable beam is made of the same thickness as the pin
extending therefrom.
Referring now to FIG. 2 a cross-section of a portion of connector
10 is illustrated showing that the angle .theta. subtended by the
ends of the curved portion 48 and 50 may be varied as desired. It
has been found, however, that angle .theta. in a preferred
embodiment is preferably 90.degree. to maximize lateral
deflection.
Referring now to FIG. 3, with connectors of the type described,
printed circuit boards 56 may be arranged in a stacked
configuration and interconnected by the subject connectors. The
connectors illustrated by the reference characters 60 are located
in a unitary elongated connector body as shown. The sandwich
structure illustrated is accomplished by throughbolting the
sandwiched structure with the bolts 62.
Interconnection is accomplished, as illustrated in FIG. 4, by the
placement of a printed circuit board 64 between two connectors,
illustrated in this figure by reference characters 66 and 68. On
the bottom of printed circuit board 64 is a conductive strip 70
which is in electrical contact with contact pin 72 from connector
66. The connection is most easily made by creating a hole in both
the printed circuit board and its conductor and inserting the pin
from connector 66 through this hole. If the hole is throughplated,
no further connecting means may be necessary. Alternatively the pin
may be soldered, braised or otherwise electrically connected to the
conductor on the printed circuit board after insertion of the pin
through the hole. This connection method establishes an electrical
connection between conductor 70 and a spring member 74 carried by
connector 68 by virtue of the insertion of pin 72 into connector
68. These interconnections can obviously be selectively made such
that selected conductors of one printed circuit board may be
connected to selected conductors of the circuit board either above
or below it.
Referring to FIG. 5, it will be appreciated that defective circuit
boards may be replaced by another circuit board-connector
combination illustrated by the combination of circuit board 64 with
connector 66. This provides a convenient stacking and replacement
system for circuit boards which eliminates the necessity of a
separate rack mounted connector strip.
The subject connector can also be used in a conventional printed
circuit board connector system as illustrated in FIG. 6, in which a
printed circuit board 80 may be provided with the subject connector
illustrated by the reference character 82, in which the connector
is mounted at one end of the circuit board. Alternatively, any
suitably configured male pin connector strip may be mounted on and
connected to the printed circuit board, it being understood that
use of the subject connector is convenient since only one lot of
connectors need be ordered for both the printed circuit board
connector and the rack mounted connector. In this mounting system,
the subject connector is also adapted as a rack mounted connector
strip 84 which is bolted to the rack into which the printed circuit
board is to be inserted.
Connector 82 may have its individual conductors connected to
printed circuit board 80 in the manner illustrated, e.g. by
connecting wires 86 from spring extensions 88 to contact pads 90 on
the circuit board. Alternatively, as illustrated in FIG. 7, any
projecting portion of a leaf spring may be inserted into an
appropriate hole in the circuit board to eliminate the necessity of
separate wires. For example, in FIG. 7 pin 100 projects through
through-plated hole 102 in printed circuit board 104 and is
connected to a conductive strip 106 to mount the connector on the
circuit board as well as connect it thereto.
Referring back to FIG. 6, the circuit board may be secured to the
rack mounted connector by bolts such as the bolt illustrated at 92.
It will be appreciated that unlike the aforementioned cam-actuated
release mechanisms the head of the bolt is accessable along the
same direction as the direction of insertion of the printed circuit
board thereby to facilitate connector mating.
What has been provided, therefore, is a unitary, initial zero
insertion force and full zero retraction force, hermaphroditic
connector having a folded spring configuration for providing both
the male and female members of the connector. In one embodiment the
folded spring is 24 .times. 24 mills which is precisely the
standard pin dimensions for printed circuit board connectors.
Because the female portion of the connector is only one-half as
thick as the male portion, the force necessary to make adequate
frictional contact is minimized. Moreover, for added strength the
folded portion of the spring member in its housing provides for
considerable structural stability of the pin. It is obvious that
the spring member can be made of any suitable spring material such
as beryllium copper, spring brass, etc. and may take on any
convenient housing configuration to accomodate cables as well as
printed circuit boards.
Although a specific embodiment to the invention has been described
in considerable detail for illustrative purposes, many
modifications will occur to those skilled in the art. It is
therefore desired that the protection afforded by Letters Patent be
limited only by the true scope of the appended claims.
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