Note: Descriptions are shown in the official language in which they were submitted.
CA 0222823~ 1998-01-28
577-155 CIP
IMPROVED SI~GLE-SIDED. STRADDLE MOUNT
PRINTED CIRCUIT BOARD CONNECTOR
BACKGROUND OF THE INVENTION
This a continuation-in-part application of U.S. Serial No. 08/735,852,
filed on October 23, 1996.
1. Field of the Invention
This invention relates to electrical connectors and more particularly to an
electrical connector for connection to an edge of a single-sided printed circuit board.
] 0 2. Description of the Prior Art
There are a wide variety of electrical connector assemblies which are adapted
to be mated to an edge of a printed circuit board. Many of these edge connectorsinclude a mating slot which receives a tongue portion projecting from an edge of a
printecl circuit board. Many such connectors also include fastening means, such as
] 5 screws or bolts, for mounting the connector housing to the printed circuit board.
In most such electrical edge connectors which have elongated slots for
receiving an edge portion or end of a board, a plurality of tern~inals are mounted in the
housing along the slot, and spring contact portions of the terminals are biased against
contact pads on either one or both sides of the printed circuit board. These types of
connectors generally suffer from the disadvantage of connector tilting which maycause interruption of the electrical pathway or bending of the contacts. To overcome
this problem, many connectors rigidly clamp the board within the connector slot
against movement perpendicular to the plane of the board. Such clamping often
includes the use of screws traversing holes found in the printed circuit board. Such
throu,~h-hole clamping means is not suitable for certain manufacturing and assembly
processes, such as oven/IR reflow soldering.
CA 0222823~ 1998-01-28
Rigidly clamping the connector to the printed circuit board causes a myriad of
other problems. Such problems include the spring contact portions of the terminals
losing their resiliency and, accordingly, the effective biased engagement with the pads
on the priinted circuit board. Additionally, problems arise from stress cracks produced
in the areas surrounding the fastening means which lock the connector to the board.
Such stress cracks may create open circuits if the crack traverses a printed circuit.
To avoid the problems associated with edge connectors, conventional header
designs are typically surface mount connectors or right-angle connectors. Surface
mount connectors usually use "hooks" to secure the connector to the printed circuit
board. This design suffers greatly from connector tilling problems, similar to the
previously described edge connectors, as well as problems associated with solder lead
coplanarity control. These problems lead to connector manufacturing difficulties and
poor solder joint formation during automated soldering processes to couple the solder
leads to the solder pads of the printed circuit board.
Right-angle connectors also suffer the disadvantage of tilting as well as
kinking of the solder leads which are used to assist in holding the connector upright.
To avoid tilting and kinking problems, these connectors generally utilize screws and
mating through holes on the printed circuit board to rigidly couple the connector to
the board. Thus, right-angle connectors suffer from the disadvantages set forth above
regarding stress cracks as well as manufacturing and assembling difficulties discussed
above.
The present invention overcomes the problems set forth above to provide a
superior ,iesign substitute for surface mount and right-angle printed circuit board
connectors.
CA 0222823~ 1998-01-28
SUMMARY OF THE INVENTION
I t is an object of the present invention to provide an improved single-sided,
straddle mount connector for mounting to a printed circuit board.
It is a further object of the present invention to provide a single-sided, straddle
mount printed circuit board edge connector having improved positive grip on the
printed circuit board.
It is yet another object of the present invention to provide a single-sided,
straddle mount printed circuit board edge connector having improved Z-height control
without ,acrificing connector rigidity.
It is still a further object of the present invention to provide a single-sided,straddle mount printed circuit board edge connector having improved solder jointformation by positively pre-loading the leads onto the printed circuit board to ensure
good mating contact.
Ilt is yet another object of the present invention to provide a single-sided,
straddle mount printed circuit board edge connector adapted to accommodate and
correct warpage of thin printed circuit boards which often occurs during the soldering
process.
It is still a further object of the present invention to provide a single-sided,straddle mount printed circuit board edge cormector having a plurality of gripper or
arm assemblies on the connector which provide an effective means for correcting
printed circuit board warpage.
It is still a further object of the present invention to provide a single-sided,straddle mount printed circuit board edge connector having positive grip gripper arrn
CA 0222823~ 1998-01-28
assemblies on the connector which eliminate tilting of the connector with respect to
the printed circuit board.
It is yet another object of the present invention to provide a single-sided,
straddle mounted printed circuit board edge connector having irnproved coplanarity
control of solder leads, leading to simpler and easier manufacturing processes due to
increasecl tolerances.
It is still another object of the present invention to provide a plastic, single-
sided, straddle mount printed circuit board edge connector which provides enhanced
plastic rigidity using I-beam and C-channel designs for the gripper arm assemblies.
It is yet a further object of the present invention to provide a plastic, single-
sided, straddle mount printed circuit board edge connector which improves plastic
material ~low to thin sections of the connector during injection molding.
In accordance with one form of the present invention, the connector for edge
mounting~ onto a single-sided printed circuit board includes an insulative housing
having top and bottom walls, opposed side walls, and a rear wall forming a header
assembly. The rear wall includes at least one opening extending therethrough andhaving positioned therein an electrical contact. The electrical contact includes a
contact pin portion which is positioned within the header assembly and a solder lead
extending from the rear wall of the housing in a direction opposite from the header
assembly. The connector further includes a plurality of gripper arm assemblies which
are spaced along the insulative housing and extend perpendicular from the rear wall of
the header portion of the connector in the direction of the solder lead. Each of the
gripper arm assemblies includes an upper and lower gripper arm defining
therebetween a receiving space for receiving the edge of the printed circuit board.
The gripper arm assemblies provide positive mechanical locking of the printed circuit
board to the connector so that the solder lead is in mating electrical connection with
the solder pad of the printed circuit board upon insertion therein.
CA 0222823~ 1998-01-28
The gripper arm assemblies may be in the form of simply providing an upper
and lower gripping arm or, in the alternative, may be configured as either an I-beam or
C-channel shaped. In the gripper arm assembly configured in the shape of an I-beam,
the assembly includes upper and lower gripper arms and a vertical extending member
disposed between and coupled to the upper and lower gripping arms to form
substantially an I-shaped cross-section. In order for the printed circuit board to be
inserted into the I-beam shaped gripper arm assembly, the printed circuit board
includes a slot therein for mating engagement with the vertical extending member of
the I-beam.
The gripper arm assembly configured in the shape of a C-channel includes a
vertically extending member coupling an outside surface of the upper and lower
gripper alms to form the gripper arm assembly having a C-shaped cross-section.
Depending on the location of the C-channel shaped gripper arm assembly along theedge of the printed circuit board, the printed circuit board may include a slot therein
for mating engagement with the vertical extending member of the C-channel.
The connector is preferably integrally molded to include the header and
gripper alm assemblies as a unitary body. The contacts may be press fit into openings
in the rear wall of the header assembly to form the cormector in accordance with the
present invention. The gripper arm assemblies of the present invention provide
superior mechanical connection to the printed circuit board and avoids connectortilting problems without the use of any fastening means such as through holes and
screws. The connector of the present invention also provides an easily
manufacturable structure which can be simply assembled onto an edge of a single-sided printed circuit board.
A preferred form of the single-sided, straddle mount printed circuit board
connector, as well as other embodiments, objects, features and advantages of this
invention will be apparent from the following detailed description of illustrative
CA 0222823~ 1998-01-28
embodiments thereof, which is to be read in conjunction with the accompanying
drawings
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top perspective view of the single-sided, straddle mount
connector formed in accordance with the present invention coupled to an edge of a
printed circuit board;
Figure 2 is an enlarged detail of the connector and printed circuit board shown
in Figure l;
Figure 3 is a rear elevational view of the connector header assembly formed in
accordance with the present invention;
Figure 4 is a top plan view of the connector formed in accordance with the
present invention;
Figure 5 is a cross-sectional view of a connector formed in accordance with
the present invention illustrating the connector insertion direction onto an edge of a
printed circuit board;
Figure 6A is a front elevational view of the connector formed in accordance
with the present invention illustrating the printed circuit board seating plane and the
coplanarity tolerance of the connector solder leads;
Figure 6B is an enlarged perspective detail ofthe connector solder tail formed
in accordance with the present invention in mating electrical connection with a solder
pad of a printed circuit board;
CA 0222823~ 1998-01-28
F'igure 7 is a front elevational view of the connector formed in accordance
with the present invention and printed circuit board warp correction provided by the
connector gripper arm assemblies;
F'igure 8 is an end view of the connector and gripper arm assembly with a
S printed circuit coupled thereto;
F'igure 9 is a perspective view of a connector gripper arm assembly configured
in the shape of an I-beam and a mating portion of a printed circuit board;
F'igure 10 is a vertical cross-sectional view of the gripper arm assembly
configured in the shape of an I-beam illustrated in Figure 9;
F'igure 1 1 is a horizontal cross-sectional view of the gripper arm assembly
configured in the shape of an I-beam and a mating portion of the printed circuit board
illustrated in Figure 9;
F'igure 12 is a vertical cross-sectional view of a connector gripper arm
assembly configured in the shape of a C-channel.
F'igure 13 is a perspective view of a simplified auto-insertion machine for
coupling the connector on an edge of a single-sided printed circuit board.
F'igure 14 is a partial front perspective showing of a further embodiment of theconnector assembly of the present invention.
F'igure 15 is a back elevational view of the connector shown in Figure 14.
F'igure 16 is a bottom perspective view of the connector of Figure 14
supporting a printed circuit board.
CA 0222823=, 1998-01-28
Figure 17 is a bottom perspective showing of the connector of Figure 14.
DETAILED DESCR~PTION OF THE PREFERRED EMBODrMENTS
Figure 1 is a top perspective view of a single-sided, straddle mount connector
10 formed in accordance with the present invention coupled to an edge of printedcircuit board 20. The connector 10 includes a plurality of contacts or solder leads 12
which are in electrically mating connection with solder pads 14 located on a topsurface of the printed circuit board 20. Also shown in Figure 1 are a plurality of
connector gripper arm assemblies 16 which provide a positive locking means for
coupling the connector 10 to the edge of the printed circuit board.
The connector 10 is single-sided since the solder leads 12 are provided on only
one side of the printed circuit board. Many prior art devices included solder pads on
two opposing surfaces of the printed circuit board and a connector having top and
bottom contacts for electrically contacting each solder pad. These types of double-
sided printed circuit boards have many disadvantages, including manufacturing
difficulti~es, such as those associated with double reflow and double-sided solder
pasting. Since the present invention only requires a single side of the printed circuit
board to include solder pads, manufacturing speed is increased and the above-
mentioned difficulties are avoided. A printed circuit may be produced and easilypasted to a top surface of a substrate to form a printed circuit board.
Figure 2 is an enlarged detail of Figure 1. As clearly illustrated in Figure 2,
the connector contacts or solder leads 12 are spring-retention type contacts which are
frictiona]ly electrically connected to the solder pads 14 of the printed circuit board 20
upon insertion of the circuit board into the receiving space formed by gripper arm
assemblies of the connector. The solder leads 12 are shaped to be biased against an
inserted c ircuit board so that a solder tail 18 of the solder lead are electrically coupled
with a solder pad of the circuit board. The solder leads 12 include at least one bend
CA 0222X23~ 1998-01-28
along its extent and the solder tail 18 is curled upward for receiving an edge of a
printed circuit board 20 without scraping the circuit board surface.
:Figures 3 and 4 illustrate one embodiment of the header assembly of the
single-sided straddle mount connector. More specifically, Figure 3 is a rear
c; elevational view of the connector illustrating the arrangement of male connection
power pins 22 and signal pins 24. The connector housing 26 comprises an electrically
insulative material, such as glass filled PPS or PPA. The connector includes a
plurality of male power pins 22 for connection with a mating female power plug.
Furtherrnore, the connector may include any number of signal pins 24, depending
upon the application. Figure 4 is a top plan view of the connector housing illustrating
the gripper arm assemblies and spring retention contacts 28 coupled to the power pins
and the contacts 12 coupled to the signal pins of the connector. In this particular
illustrated embodiment, the connector includes three gripper arm assemblies, onegripper arm assembly at each end of the connector 16a, 16c and a third gripper arrn
l S assembly 16b located near a central portion of the connector. The connector housing
also includes an indicator 30 which may be molded into the housing, for indication the
position of the first signal pin positioned within the connector.
F igure S is a cross-sectional view of the connector 10 of the present inventionprior to c onnection with an edge of a printed circuit board 32. In practice, the
connector will be moved along a plane in the direction of an edge of printed circuit
board for mating mechanical and electrical connection therewith. The connector is
manufactured to accommodate any specified printed circuit board thickness, e.g. 1.45
mm. Accordingly, the printed circuit board is frictionally fitted between an upper 34
and lower 36 gripper arm to positively mechanically hold the connector to an edge of
the printed circuit board. The lower gripper arm 36 extends a sufficient length
perpendicular to an edge of the printed circuit board to effectively support theconnector on the edge thereof. For example, the lower gripper arm assembly is
preferably at least 4mm long extending from a rear wall 38 of the connector. Thegripper arm assemblies may be any convenient width, and are typically 2 to 5rnm in
CA 0222823F7 1998-01-28
width. E,y supporting the connector along its length with a plurality of gripper arm
assemblies, connector tilting problems are avoided.
This arrangement of a plurality of gripper arm assemblies to positively lock
the connl ctor to the printed circuit board has numerous advantages of prior designs.
For example, the novel arrangement of gripper arm assemblies elimin~tes the serious
problem of connector tilt with respect to the printed circuit board. Additionally, the
contacts or solder leads of the connector may be designed with positive pre-loadinterference to improve electrical contact with the printed circuit board solder pads
without danger of tilting the connector. Furthermore, the arrangement of gripper arrn
assemblies serve as an effective means for correcting printed circuit board warpage,
which feature will be discussed in greater detail later.
Figure 6A illustrates the positively pre-loaded solder leads formed in
accordance with the present invention. More specifically, the solder leads 12 have
solder taiils 18 with a rounded contact surface which is set below a printed circuit
board seating plane 40 defined by a gripper arm assembly receiving space 42. Thereceiving space 13 defined by an upper surface 44 of a lower gripper arm and a lower
surface 46 of an upper gripper arm. (Figure 5). Accordingly, the solder leads 12 are
positively pre-loaded onto the printed circuit board solder pads to provide goodelectrica] contact therewith. Additionally, as illustrated in Figure 6A, control of
coplanarity of the solder tails may be relaxed without sacrificing the ability to make
good elertrical contact with the printed circuit board. As shown in Figure 6A, aprinted circuit board seating plane is illustrated by dashed line 40. The contact tails
will provide good electrical contact with the printed circuit board as long as the
contact tails, in their relaxed position, are oriented below the seating plane of the
printed circuit board. However, in the event that the solder tails 18 are formed above
the printed circuit board seating plane, that is, there is an absence of preloading of the
solder leads 12 onto the printed circuit board solder pads, good solder joints may still
be attainable as long as the solder tails 18 do not lift off the printed circuit board
seating plane by a distance more than the solder pad thickness (Figure 6B). Typically,
CA 0222823~ 1998-01-28
solder pa.ds have a thickness of 0.1 Smm as illustrated by arrows A-A in Figure 6B.
Accordingly, if the solder tail is formed above the printed circuit board seating plane
by a dist.mce less than the solder pad thickness, (shown by arrows B-B in Figure 6B)
good solder joints may be formed. The tolerance of coplanarity is indicated by the
seating plane 40 and a lower limit illustrated by dashed line 42. Thus, connector
manufacturing methods and processes become simplified in view of the increased
tolerance permitted with respect to contact tail coplanarity. Also illustrated in Figure
6A are the connector openings 43 through which the male contact pins and solder
leads are mounted to the connector.
Figure 7 is a front elevational view of a single-sided, straddle mount connectorof the present invention illustrated with a warped printed circuit board 44.
Commonly, printed circuit boards tend to warp due to shrinkage or other post-
manufacl~uring conditions. Due to this warping, it becomes very difficult, if not
impossible, to use any form of edge connector and still obtain good electrical
l S connection along the entire length of the connector. The present invention which
includes a plurality of gripper arm assem61ies can effectively correct printed circuit
board warpage and ensure good electrical contact. As shown in Figure 7, the single-
sided, straddle mount connector includes three gripper arm assemblies 16a, 1 6b, 1 6c,
illustrated in an I-beam configuration to be discussed in greater detail later, which
upon connection to an edge of a warped printed circuit board 44, will tend to
straighten and positively grip the printed circuit board. Warpage becomes a
significant problem with thin printed circuit boards and, this problem can be rectified
by the arrangement of gripper arm assemblies on a single-sided connector of the
present invention. Once the warped circuit board is in place in the connector of the
present invention, the circuit board warp is corrected to provide a substantially planar
connection surface 46.
Figure 8 is an end view of the single-sided, straddle mount connector
illustrating a gripper arm assembly having a single-sided, paste on printed circuit
board seated within the gripper arm assembly receiving space. The gripper arm
CA 0222823~ 1998-01-28
assembly includes a lower arm 36, having an upper surface which determines the Z-
height (center line offset) of the printed circuit board. Specifically, depending upon
the positioning and/or thickness of the lower gripper arm 36, the Z-height of the
printed circuit board is determined. The particular configuration of the upper gripper
arm 34 and lower gripper arm 36 provides superior Z-height control.
The connector housing 26 is preferably an integrally molded unit having the
connector header 27 (Figures 3 and 4) and gripper arm assemblies 16a, 16b, 16c
integrally forrned. The connector header includes top and bottom walls, opposed side
walls and rear wall 38. The connector contacts, comprising a male connector pin at
one end ~md a solder lead at an opposite end, may include rectangular transitionsection 49 (Figure 6), which may be press fit into contact receiving spaces 43 molded
into the housing. The contacts include a single-sided solder lead on the printed circuit
board receiving side and male connector pins for coupling to mating female
connectors within the header assembly of the connector. The gripper arm assemblies
16a, 16b. 16c include a receiving space 42 between the upper 34 and lower 36 gripper
arms, the receiving space 42 being specifically dimensioned to receive a printedcircuit board having a specified thickness.
In the embodiment shown in Figure 8, the lower gripper arrn 36 is
substantially rectangular in shape and having a rectangular cross-section. The upper
gripper arrn 38 is also substantially rectangular in shape, but being tapered away from
the header 27 towards the printed circuit board receiving space opening and having a
substantially rectangular cross-section throughout its length.
The lower gripper arm 36 may include on a top surface thereof at least one
projection or crush rib 48 extending upward from the top surface thereof to engage the
2~ lower surface of the printed circuit board. The at least one projection or crush rib 48
aids in providing a positive mechanical lock of the connector onto the edge of the
printed circuit board. In one embodiment, a single crush rib may be centrally located
on an upper surface of the lower gripper arm. Alternatively, as shown in Figures 7
CA 0222823~ 1998-01-28
and 9-1 1, a pair of crush ribs 48 may be provided on opposite sides of the lower
gripper arm for deflection upon engagement with the lower surface of a printed circuit
board.
C)nce good mechanical and electrical connections are forrned by the gripper
S arm assemblies of the present invention, the solder tails may be fused to the solder
pads of the printed circuit board. Such fusing may be accomplished by oven/IR
reflow soldering thus providing a fast, reliable electrical connection therebetween.
F igures 9- 1 1 illustrate alternative embodiments of forming the gripper arm
assemblies of the present invention. More specifically, Figure 9 illustrates a gripper
arm assembly 16 and connector housing header wherein the gripper arm assembly has
an I-beam construction. More specifically, the gripper arm assembly 16 includes a
lower griipper arm 36 and an upper gripper arIn 34 defining a printed circuit board
receivingr space 42 therebetween and a strengthening rib 50 assembly centrally located
in the circuit board receiving space. The strengthening rib 50 is integrally formed into
the lower surface of the upper gripper arm and the upper surface of the lower gripper
arm. The I-beam construction provides enhanced strength to the gripper arm
assembly.
The I-beam construction allows the thin plastic sections of the gripper arm
assemblies to withstand heavier loads without risk of fracture. Since the I-bearn
construction provides enhanced strength to the gripper arm assembly, a wider range of
Z-heights are available since the lower gripper arm may be made thinner without
sacrificing connector load capabilities. However, when utili7ing the I-beam
construcl:ion, it will be necessary to provide a slot 52 in the printed circuit board for
accommodating the strengthening rib of the gripper arrn assembly as shown in Figure
9. The slot 52 in the printed circuit board and I-beam construction of the gripper arm
assembly act as a printed circuit board-to-connector alignment means. Accordingly,
the printed circuit board solder pads will be closely aligned with the solder leads of
CA 0222823~ 1998-01-28
14
the conn ector to ensure good electrical connection to all solder pads on the printed
circult.
'i~et another advantage of the I-beam construction is improved
marLufacturability of the connector. More specifically, the connector is preferably
injection molded plastic in an integrally formed device. However, problems may arise
in the in jection molding process due to poor plastic flow to thin sections of the
connector, e.g. the gripper arm assemblies. The I-beam construction provides
improved plastic flow to the thin sections of the gripper arm assemblies to enhance
the overiall plastic injection molding process.
Also shown in Figure 9 are the crush ribs 48 which are provided on the upper
surface of the lower gripper arm 36. The crush ribs 48 are substantially triangular-
shaped projections having a peak which extends above the upper surface of the lower
gripper arm on opposing side edges thereof. As previously discussed, the crush ribs
48 are aclapted to slightly deflect to ensure a positive mechanical lock of thLe connector
to the edge of the printed circuit board. The crush ribs 48 are clearly illustrated in
Figures l O and 1 1 which are partial cross-sectional views of the connector and gripper
arm assemblies shown in Figure 9.
F igure 10 is a partial vertical cross-sectional view of the connector housing
and gripper arm assembly formed in accordance with the I-beam construction
described above. Also illustrated in Figure 10 are the openings 43 molded into the
housing which are adapted to receive the connector contacts. As previously noted, the
connector contacts may be press-fit into the housing openings 43 so that a male
connection pin end is available for connection within the header portion of the
connector and the solder leads 12 extend in an opposite direction for frictionally
engaging solder pads on a top surface of a printed circuit board.
Figure 11 is a partial horizontal cross-sectional view of the connector housing
27, strengthening rib 50 and lower gripper arm 36. ThLe strengthening rib 50 is
CA 0222823F7 1998-01-28
integrally molded to the connector housing and lower gripper arm. The strengthening
rib 50 is dimensioned to fit within the slot 52 formed in the printed circuit board for
alignment of the connector with the printed circuit board.
Figure 12 illustrates a further alternative embodiment in perspective view for
the gripper arm assembly. Figure 12 illustrates a partial vertical cross-section of a C-
channel gripper arm assembly design in which a receiving space is defined between an
upper 34 ~md lower arm 36 portion and a rear portion 54 connecting the upper andlower gripper arm portions. Once again, the C-channel design affords the strength
advantages in the thin plastic sections of the gripper arm assembly. The C-channel
design also allows for broader design options with respect to Z-height of the
connector.
It should be understood by those skilled in the art that the different gripper arm
assembly designs may be used in any combination in the connector design. For
example, -the cormector may include C-channel design gripper arm assemblies on the
end portions of the connector and at least one I-beam gripper arm assembly along the
length of the connector. Alternatively, the connector may include all I-beam design
gripper arm assemblies or standard gripper arm assemblies (Figure 5) which include
only an upper and lower gripper arm extending from the connector housing.
Figure 13 illustrates a simplified auto-insertion machine for coupling the
single-sided, straddle mount connector of the present invention to an edge of a printed
circuit board. The auto-insertion machine includes a m~g~7ine holder for stacking a
plurality of connectors 10 and an insertion device 62 for pushing the connector 10
onto the edge of the circuit board 20. The insertion device includes a pneumaticcylinder 64 having an insertion block 66 coupled to the reciprocating rod 68 of the
cylinder. Upon activation of the cylinder, the insertion block 68 contacts the header
portion of the connector which is pushed in the direction of arrow A to contact an
edge of the circuit board 20. The connector spring retention solder leads are
frictionally, electrically coupled to the solder pads on the circuit board upon complete
CA 0222823~ 1998-01-28
- 16
insertion of the connector onto the edge of the circuit board. A soldering process may
then perrnanently fuse the solder leads to the solder pads. Accordingly, the present
invention provides a positive mechanical lock and reliable electrical connection to a
single-sided, printed circuit board utilizing a simple assembly process. T'he assembly
process does not require any additional connection devices, such as threaded screws,
to ensure good mechanical and electrical contact. The gripper arm assemblies
positively engage the edge of the circuit board to ensure a good mechanical
connection.
T'he single-sided, straddle mount printed circuit board connector of the presentinvention overcomes the disadvantages of surface mount and right-angle connectors,
includingr connector tilting and provides positive mechanical and electrical coupling
with the circuit board. Furthermore, the assembly process of the connector to the edge
of the circuit board is simplified. Manufacturing of the connector is also simplified in
view of the higher tolerances perrnitted for coplanarity of the contact solder tails
without sacrificing good electrical connection to the solder pads of the printed circuit
board. The connector of the present invention is also effective in correcting printed
circuit board warpage using the gripper arm assemblies described herein.
A s particularly shown in Figures 4, 6, and 7, the present invention provides for
securing printed circuit board 40 to connector 10 in a manner which accommodatesvariation in the coplanarity of the solder tails 18 exten(ling from housing 26. T'he
present invention also compensates for a certain degree of printed circuit boardwarpage, assuring that such warpage of the printed circuit board is corrected thereby
providing good electrical engagement between the solder tails 18 and the pads on one
surface of the printed board over the entire length of the connector. As described
above, this is achieved by use of gripper arms 16 which extend from housing 26.
Particularly with respect to signal pins 24, both coplanarity of the solder tails 18 and
printed board warpage is accomrnodated by gripper arm l 6c, at one end of housing 26
and third gripper arm l 6b located along a central portion of housing 26. While such
arrangernent and positioning of the gripper arms is adequate for the intended
CA 0222823~ 1998-01-28
purposes, it is further contemplated that additional compensation for printed circuit
board warpage and lack of coplanarity of solder tails may be further addressed by the
addition of an interrnediate gripper arm specifically associated with contacts 12 of
signal pins 24.
E' eferring now to Figures 14-17, single-sided straddle mount connector 10 may
addition~lly include an intermediate protrusion 17 which, as particularly shown in
Figures 16 and 17, is supported along a bottom surface 26a of housing 26 and extends
forward of a front edge 26b thereof. Protrusion 17 which serves as an additionalgripper arm is located approximately equidistant between gripper arm 1 6c and gripper
arm 1 6b. Between such expanse, connector 26 supports at least one row of densely
arranged. signal contacts having solder tails 18 extending therefrom. While the
arrangen:lent of the gripper arm 1 6a, 1 6b and 1 6c described above adequately provides
for a certain degree of non-coplanarity of solder tails 18 and a certain degree of
printed c ircuit board warpage, the positioning and location of intermediate protrusion
17 compensates for additional non-coplanarity ofthe solder tails and a higher degree
of printed circuit board warpage.
Non-coplanarity of the solder tails as well as printed circuit board warpage,
especial]y along the solder tails 18 of the signal contacts, can result in incidents of
non-sold.ered connections between certain of the solder tails 18 and the traces on the
printed c ircuit board. Such problems are especially encountered when the connector
is being implemented by the end user where variations in the thicknesses of the
printed c ircuit board may result in a relatively thin board being employed. Such a thin
board would enhance the above noted problems. Also storage of these boards at a
user's location may, over time, result in enhanced warpage problems. Still further
during the soldering process, PC boards have a tendency to be warped or deformedwhen exposed to high temperatures necessary for effecting a proper solder. Problems
my also be encountered in the connector itself . In certain instances, warpage or
deformation of the plastic connector housing is possible due to built-in molding
CA 0222823~ 1998-01-28
18
stresses which may occur during the formation of the connector or due to high
temperat~lre exposure during the soldering process.
The addition of intermediate protrusion 17 additionally addresses such
problems and results in more accurate and reliable solder connections bet~,veen solder
S pads 18 and the traces on printed circuit board 20. This is especially significant along
the extent between gripper arm l 6b and end gripper arm 1 6c such extent being
unsupporl:ed in the embodiment shown above in Figures 4, 6 and 7.
As set forth above, protrusion 17 may be integrally formed with connector
housing 26. Protrusion l 7, along with gripper arms 1 6b and 1 6c, forms a boardreceiving space with solder tails 18 for receipt of the edge of board 40. The board
receiving space is such that the solder tails are biased against the edge of printed
circuit board 40 assuring spring engagement therewith so as to compensate for lack of
coplanarily of the tails along the entire row of contacts. Further, the upper surface 1 7a
of protrusion 17 may include a central crush rib 1 7b extending therefrom for
engagement with board 40 to help m~int~in the board 40 in place. The crush rib 17b
may also be used to locate and align the board in the board receiving space.
Although illustrative embodiments of the present invention have been
described herein with reference to the accompanying drawings, it is to be understood
that the invention is not limited to those precise embodiments, and that various other
changes and modifications may be effected therein by one skilled in the art without
departing from the scope or spirit of the invention.
