Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: LOW PROFILE TEST CLIP
This invention relates generally, as indicated, to test clips for
electrical and electronic components, and, more particularly, to such test
clips that have a low profile to facilitate placement in close quarters and to
minimize antenna effect. The invention has particular, though not
exclusive, application for interconnection with the input/output leads of an
electrical component or device, such as an integrated circuit, for the
purpose of attaching test equipment to the leads of a dual-in-line (or other
lead configuration) package having multiple, say 14, 16, 32, 40, etc., leads.
However, the invention lends itself for use with any number and/or
arrangement of leads in other electrical and/or electronic packages.
Moreover, the invention may be used for purposes other than testing, such as
signal injecting, signal reading, circuit and/or device connecting, and like
purposes.
An example of a prior test clip is one that has a pair of finger
members or bodies that are pivotable with respect to each other and are
connectable to an integrated circuit package while extending primarily in a
direction perpendicular to or out of the major planar extent of the
integrated circuit package. Each such finger member or body carries plural
electrical contacts or conductors, which also extend generally in parallel
with the integrated circuit leads relatively far out of the major planar, say
of the top, extent of the integrated circuit package, that are intended to
connect with the integrated circuit leads at one end of the finger members
or bodies and that extend far enough away from such leads to facilitate
connection to other external electrical devices, equipment, probes, etc.
Heretofore, such test clips and other electrical connectors used for such
testing and other purposes with respect to integrated circuits, for example,
have been relatively large or bulky. Although such test clips have been
quite satisfactory for use during the breadboarding of a circuit in the circuit
design process and during testing of integrated circuits mounted on printed
circuit boards which are conveniently mounted on a test bench or in a
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relatively spacious electrical or electronic device, they are not suitable for
in situ connecting with integrated circuits located in rather confined areas.
Due to the relatively extended length of the conductors/contacts
of such prior test clips, the same tend to produce an antenna effect.
Therefore, use of such test clips for testing high speed signals, such as those
with which transmission line type cable often is required, may be
unsatisfactory due to the encountered and/or produced electrically noisy
environment.
During the installing of an integrated circuit test clip on an
integrated circuit package, a frequently encountered problem is the
misalignment of the respective contacts of the test clip relative to the
integrated circuit leads. Such misalignment may cause damage to such
leads and/or the integrated circuit package, spurious test results, and, in the
event that signals are injected into the integrated circuit via the test clip,
possible damage to the integrated circuit due to incorrect signal input, short
circuiting, etc.
The present invention is an electrical clip-like connector that
has a low profile and is capable of connecting the conductors of an
electrical cable, for example, with the leads of an integrated circuit
package or the like. Due to the low profile configuration of the invention, it
may be used in situ in confined environments, and it also may be used for
coupling relatively high speed signals without or with minimum antenna
effect. Other features of the invention include a locating mechanism that
facilitates applying the clip connector to an integrated circuit, for example,
assuring proper alignment of the contacts and leads and a preferred
contact/support arrangement to help assure good electrical connection with
the integrated circuit leads and tolerance for size and location errors while
avoiding overstress damage to the contacts. Still other features of the
invention include the ability to pack closely the contacts thereof preferably
in dual-in-line opposed contact pair arrangement, for example to the same
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extent that the conductors of a ribbon cable are relatively positioned, the
ability to ground or otherwise to connect in common certain ones of such
conductors and/or contacts, and a resilient connection mechanism for the
connector body portions, which also preferably relies on the characteristics
of the electrical cable to which the body portions are connected (preferably
by direct molding thereto) to stabilize and to strengthen the connection
between such body portions and permits relative movement thereof to
install or to remove the clip-like connector relative to, for example, an
integrated circuit device or the like. Even other features will become more
apparent as the following description proceeds. The invention also includes
a handle to install and to remove the clip-like connector with respect to an
integrated circuit package or the like.
According to one aspect of the invention, a low profile clip
connector for electrical devices that have plural rows of electrically
conductive leads includes a pair of clip bodies, each including a plurality of
electrical contacts and an electrically non-conductive support, an electrical
cable having therein a plurality of electrical conductors, a plurality of the
electrical contacts being electrically connected to respective electrical
conductors at respective junctions thereof, the supports being molded to the
cable and contacts to enclose the respective junctions while leaving
respective contacting portions of the contacts exposed for connection to
respective leads of such an electrical device, and a coupling mechanism for
coupling the pair of clip bodies with respect to each other in positions to
enable the contacts to connect with respective leads of such an electrical
device.
According to another aspect, the invention relates to a low
profile electrical clip connector, including an electrical cable, having a
plurality of electrical conductors, a pair of clip bodies molded to the cable,
each body including plural electrical contacts having exposed contacting
portions for engaging leads of an electrical device and a mounting portion
molded in the body, respective mounting portions being electrically
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connected to respective conductors of the cable, and electrically non-
conductive separator walls between respective pairs of relatively adjacent
contacts, and a coupling mechanism for coupling the pair of bodies with
respect to each other for mounting of the clip connector of an electrical
device with respective electrical contacts engaged with respective leads of
such device.
An additional aspect relates to a low profile clip connector for
integrated circuits and the like, including a plurality of electrically
conductive contacts, an electrically non-conductive holder support body for
holding the contacts in relative positions with respect to each other, the
holder support body having curved wall surfaces for supporting the contacts
for bending relative to such wall surfaces without overstressing of the
contacts, and a back-up wall surface for limiting the maximum bending of
the contacts to prevent such overstressing, each of the contacts including a
mounting portion secured relative to the holder support body, a curved
intermediate portion positioned in generally overlying relation with respect
to the curved wall surface, and a contacting portion resiliently extending
from the curved intermediate portion away from the back-up wall surface in
position to connect with a contact placed to engagement therewith and to
deflect resiliently toward the back-up wall surface upon such engagement.
According to a further aspect, a handle is provided for
manipulating a low profile clip-like connector for integrated circuits and the
like. The connector includes a pair of electrically non-conductive support
bodies mounted with respect to each other for relative pivoting, each
support body carrying plural electrical contacts. The handle manipulates
such connector with respect to such an integrated circuit or the like to
place such contacts into or to remove such contacts from engagement with
leads of such entegrated circuit or the like, and includes a pair of handle
bodies, each including a gripping jaw for gripping a respective support body
to form a relatively rigid extension thereof and a force applying arm for
receiving force applied thereto to pivot respective pairs of a gripping jaw
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and a support body with respect to the relative mounting of such support
bodies, and a connecting device for connecting the handle bodies together
while permitting coupling of the handle bodies to respective support bodies
and relative movement of the latter in response to such force being applied
to the arms.
In the following description the invention will be referred to as a
test clip, for according to the preferred embodiment and best mode of the
invention, such device is intended for use to test the operability of and the
functions of an integrated circuit device and other devices to which such
integrated circuit device may be connected. However, it will be appre-
ciated that the invention, including the various one or more features
thereof, may be used with devices other than integrated circuits and for
electrical connection purposes that are other than testing purposes. Refer-
ences to integrated circuit and to integrated circuit package are equiva-
lently used and are intended to be exemplary only of a device to which the
test clip of the invention may be connected; preferably such device has
plural, e.g. dual-in-line lead configuration to which the test clip contacts
conveniently may be connected. Reference to lead herein, though, generally
may be construed as a reference to an electrically conductive member, such
as a lead or contact associated with a dual-in-line package (DIP) electronic
device or other electrical or electronic device to which the test clip of the
invention may be connected. Additionally, references to electrical and to
electronic may be used equivalently herein.
The above and other objects, features and advantages of the
present invention will become more apparent from the description below and
the accompanying drawings.
In view of the foregoing the invention provides a low profile clip
connector for an electrical device that has plural rows of electrically
~h conductive leads, comprising: an electrical cable including a plurality of
insulated electrical conductors maintained in generally coplanar and parallel
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relationship; a pair of clip bodies each including an electrically non-
conductive support for plural electrical contacts, said contacts being
electrically connected at respective junctions to respective electrical
conductors of said cable at insulation-removed portions thereof, and said
supports being molded to said cable and respective contacts to enclose the
respective junctions while leaving respective contacting portions of said
contacts exposed for connection to respective leads of the electrical device;
and coupling means for coupling said pair of clip bodies with respect to each
other for relative movement away from each other to enable insertion of
the electrical device therebetween and towards each other to engage the
contacts to respective leads of the electrical device.
Further in view of the foregoing the invention provides a low
profile clip connector for an electrical device that has plural rows of
electrically conductive leads, comprising: an electrical cable having therein
a planar arrangement of parallel electrical conductors; a pair of clip bodies
joined to said cable at respective locations along its length, each clip body
including an electrically non-conductive support for electrical cont~cts
electrically connected at respective junctions to respective conductors of
said cable, and each contact having a contacting portion exposed for
connection to a respective lead of the electrical device; and resilient means
for coupling said pair of clip bodies for relative pivotal movement substan-
tially about an axis disposed essentially in or close to the plane of said
planar arrangement of conductors, such pivotal movement enabling move-
ment of the connecting portions of contacts in one body away from those in
the other body to permit insertion of the electrical device therebetween and
biased return movement to engage the connecting portions of the contacts
to respective leads of the electrical device.
Further in view of the foregoing the invention provides a low
profile clip connector for an electrical device that has plural rows of
electrically conductive leads, comprising: a nat electrical cable including a
plurality of substantially coplanar electrical conductors; a pair of clip bodies
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joined to said flat cable at respective locations along its length, each clip
body including an electrically non-conductive support for plural electrical
contacts, and said contacts being electrically connected at respective
junctions to respective electrical conductors of said cable; and coupling
means substantially in or closely adjacent the plane of said flat cable for
coupling said pair of clip bodies with respect to each other for relative
movement away from each other to enable insertion of the electrical device
therebetween and towards each other to engage the contacts to respective
leads of the electrical device.
Further in view of the foregoing the invention provides a low
profile clip connector for integrated circuits and the like, comprising: a
plurality of electrically conductive contacts; and an electrically non-
conductive holder support means for holding said contacts in relative
positions with respect to each other; said holder support means having
respective curved wall surface means for supporting said contacts for
bending relative to said wall surface means while preventing stress concen-
trations that could overstress the contacts, and a back-up Wdll surface
means for limiting the maximum bending of said contacts to prevent such
overstressing, said back-up wall surface means forming a substantially
tangential continuation of said curved wall surface means; and said contacts
comprising a mounting portion secured relative to said holder support
means, a curved intermediate portion positioned in generally overlying
relation with respect to said curved wal1 surface means, and a contacting
portion resiliently extending from and substantially along the arc of said
curved intermediate portion away from said back-up wall surface means in
position to connect with a contact placed to engagement therewith and to
deflect resiliently toward said back-up wall surface means upon such
engagement.
Further in view of the foregoing the invention provides a low
profile clip connector for an electrical device that has plural rows of
electrically conductive leads, comprising: a pair of clip bodies, each
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including a plurality of electrical contacts and an electronically non-
conductive support; an electrical cable including a plurality of insulated
electrical conductors; a plurality of said electrical contacts being electri-
cally connected to respective electrical conductors at respective junctions
thereof; said supports being molded to said cable and contacts to enclose
said respective junctions while leaving respective contacting portions of said
contacts exposed for connection to respective leads of such an electrical
dèvice; and coupling means for coupling said pair of clip bodies with respect
to each other for relative movement away from each other to enable
insertion of the electrical device therebetween and towards each other to
engage the contacts to respective leads of the electrical device, said
coupling means comprising a plurality of stacked leaf springs positioned at
respective lateral ends of said bodies; and, in combination with said
connector, a handle for manipulating said connector, said handle including a
pair of handle bodies each including gripping jaw means for gripping a
respective clip body to form a relatively rigid extension thereof and force
applying arm means for receiving force applied thereto to pivot respective
pairs of said gripping jaw means and clip bodies while distorting said leaf
springs, said jaw means being positioned proximate lateral edges of said
handle bodies for positioning in approximately aligned position with respect
to said leaf springs when so engaged with said clip bodies.
Further in view of the foregoing the invention provides a handle
for manipulating a low profile connector for integrated circuits and the like,
said connector including a pair of electrically non-conductive support bodies
mounted with respect to each other for relative pivoting-type movement,
each support body carrying plural electrical contacts and said support bodies
having lateral ends extending beyond the width of an electrical cable
extending between such support bodies, with respect to such an integrated
circuit or the like to place such contacts into or to remove such contacts
from engagement with leads of such integrated circuit or the like, com-
.6~ prising: a pair of handle bodies, each including gripping jaw means for
gripping a respective support body to form a relatively rigid extension
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thereof and a force applying arm means for receiving force applied theretoto pivot respective pairs of the gripping jaw means and support bodies with
respect to the relative mounting of the support bodies, said gripping jaw
means being positioned on said handle bodies to grip such support bodies at
the lateral ends thereof extending beyond the width of the cable; and
connecting means for connecting said handle bodies together while per-
mitting coupling of said handle bodies to respective support bodies and
relative movement of the latter in response to such force being applied to
said arm means.
Further in view of the foregoing the invention provides a handle
for manipulating a low profile connector for integrated circuits and the like,
said connector including a pair of electrically non~onductive support bodies
mounted with respect to each other for relative pivoting-type movement,
each support body carrying plural electrical contacts, with respect to such
an integrated circuit or the like to place such contacts into or to remove
such contacts from engagement with leads of such integrated circuit or the
like, comprising: a psir of handle bodies, each including a gripping jaw
means for gripping a respective support body to form a relatively rigid
extension thereof and a force applying arm means for receiving force
applied thereto to pivot respective pairs of gripping jaw means and support
bodies with respect to the relative mounting of such support bodies.
To the accomplishment of the foregoing and related ends, the
invention, then, comprises the features hereinafter fully described in the
specification and particularly pointed out in the claims, the following
description and the annexed drawings setting forth in detail a certain
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illu3tr~tlve embodlment of the Invention, th~6 béing In~c~tive, however, of
~Ut one of the varlous way~ In which the principles of the invent~on may be
employed.
In the Qnnexed dr~wings:
Flg. 1 is a partial iYometric view, p~rtly broken ew~y in sectlon,
of a low pro~ile te6t clip in ~ccordance with the InYention;
Pig. 2 19 ~ side elevation section view oi the te~t clip o~ Fig. l;
Fig. 3 i~ a top pl~n view of the tqst clip o~ Fig. l;
Fig. J Is Q side elev~tion vlew o~ the test clip looking generally
In tlle dlrection o~ the Qrrows ~--4 ot Pig. 3;
Fig. 5 18 ~ pRrti~l bottom pl~n view of the test clip looking
generally in the directlon o~ the arrow~ 5--S of Fig. 4;
Flg. 6 Ig a p~rtial elevatlon/section view of the test clip looking
generally In the dlrectlon o~ the arrows B~6 of Fig. 4;
Flg. 7 ig an enlQrged sectlon view of one o~ the ~ody portions o~
the test cllp and ot' the electrlcR1 c~ble molded directly thereln looking
generally ;n the direction o~ the Qrrows 7--7 of Flg. 3;
~: Fig. 8 is a top pl~n view of the incompletely formed contact~,
electrical csble, resllient body connectors, and ground bus reddy for molding
with respect thereto of the test clip bo~y portions;
F{g. 9 Is an end elevatlon view looklng gener~lly in the dlrection
o~ the arrow3 9--9 of Fig. 8;
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Fig. 10 is a schematic view showing plural test clips on a single
cable;
Fig. 11 is a front elevation view of a handle for installing and
removing the test clip with respect to an integrated circuit package or the
like;
Fig. 12 is a side elevation view of the handle looking generally in
the direction of the arrows 12--12 of Fig. 11; and
Fig. 13 is a side elevation view of the handle installed on a test
clip according to the invention in turn installed on an integrated circuit
package.
Referring, now, in detail to the drawings, wherein like reference
numerals identify like parts in the several figures, and initially to Fig. 1, a
low profile test clip in accordance with the invention is designated 10. The
test clip 10 includes a pair of electrically non-conductive body portions 11,
12, a plurality of electrically conductive contacts 13, a connector
mechanism 14 for connecting the respective body portions with respect to
each other, and a part of an electrical cable 15 to which the body portions
are directly molded, as will be described in greater detail below. Preferably
the contacts 13 are able to be so closely packed that connections thereof to
the cable conductors, such as those of nat ribbon cable, will not require any
spreading of the cable conductors; yet the test clip still will fit properly andconveniently onto an integrated circuit package or the like to engage
electrically the respective leads thereof.
The body portions 11, 12 preferably are identical. Each includes
an upper body 16, 17 into which mounting portions of the contacts 13, part
of the connector mechanism 14, and part of the cable 15 are molded to form
a secure, strong integral structure thereof; and the height of such upper
body portions preferably is adequate to provide a strong interconnection and
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support/holding of such other parts while such height is otherwise preferably
minimized to minimize the height profile of the test clip 10. Each body
portion 11, 12 also includes a plurality of finger or wall-like separators 20
which are integrally molded with the respective upper bodies and function
both to separate respective relatively adjacent contacts 13, preferably also
to protect the contacts from various damage, to guide the test clip 10 into
proper position with respect to the leads of an integrated circuit package,
and to hold the test clip on such package. For such purposes, and especially
the latter two, jaw-like teeth 21 protrude from the bottom of each
separator 20. In Fig. 2, the gripping function that such teeth may provide
with respect to an integrated circuit package 22is shown. Moreover, in Fig.
3, the relative orientation of the teeth 21 for separating and positioning
purposes is shown. Preferably the separators 20e and teeth 21e at the
respective lateral ends of the group thereof associated with a given body
portion 11, 12, i.e. most proximate the lateral ends lle, 12e thereof, are
wider in the hteral direction than are the other separators and teeth
therebetween. Such wider members 20e, 21e are too wide to be inserted
between a pair of leads 23 of the integrated circuit package 22 and,
therefore, prevent the test clip 10 from being positioned in what might
otherwise feel and even visuaUy appear to be proper position but actually is
a misaligned position with respect to such leads. The other separators 20
and feet 21 sre of a narrower width so as to fit in the space between
adjacent leads of an integrated circuit.
As is seen in Fig. 2, the overall height of the test clip 10 is
nearly equivalent to the height of the integrated circuit package 22. The
ability to achieve such low profile configuration is facilitated by a number
of features of the test clip 10. For example, the space required for
connecting the contacts 13 and conductors 23 of the cable 15 is minimized
because of the contact shape, the direct metal to metal connection between
the contacts and conductors via generally parallel portions of each without
requiring insulation displacement/piercing by the contacts, and the molding
of the test clip body portions 11, 12 directly to the cable, conductors
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thereof, and contacts. Further facilitating such low profile configuration
are the separating and gripping functions of the separators 20 and teeth 21
and the connector mechanism 14. Preferably there is clearance between the
cable 15 and the top of the integrated circuit package 22 for cooling and
electrical isolation purposes, if desired.
The coupling or connector mechanism 14 provides both the
means to hold the body portions 11, 12 in position relative to each other and
to enable relative pivoting, folding out or rotational type of movement of
such body portions, for example as the connector mechanism is flexed or
otherwise preferably resiliently deformed. Such flexure tends to move the
teeth 21 of one body portion 11 away from the teeth 21 of the other body
portion to open the space therebetween and between respectively opposed
contacts 13 carried by the respective body portions 11, 12 to facilitate
inserting or installing the test clip 10 onto an integrated circuit package 22,
for example, as is shown in Fig. 2; such flexure also facilitates removing the
test clip 10 from an integrated circuit package. Moreover, the connector
mechanism 14 preferably is resilient so thst after such flexure, the body
portions 11, 12 will be moved bsck into the relative positions to each other
illustrated in Figs. l and a under the influence of the connector mechanism.
After being installed on an integrated circuit package 22, as is
shown in Fig. 2, the test clip 10 securely holds to such package. The
resilient urging of the connector mechanism 14 causes the contacts 13 and
preferably the teeth 21 to engage, respectively, the leads and body of the
integrated circuit package to effect such holding function. According to the
preferred embodiment and best mode of the invention, the connector
mechanism 14 is comprised of two pairs of metal, e.g. spring steel, springs
24, 25, which operate as stacked leaf springs, one pair at each lateral end of
the test clip 10. Each of the leaf springs 24, 25 has openings 26 at the
opposite ends thereof to enable material of the respective body portions 11,
12 to be molded therethrough securing the springs thereto. A leaf spring
arrangement provides firm relative positioning of the respective body
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portions 11, 12 and yet provides the desired resiliency, both while
minimizing the amount, such as thickness and width, of material and
stiffness of the individual leaves of the composite leaf spring required.
Therefore, using leaf springs 24, 25 in the connector mechanism 14 further
is conducive to the low profile configuration of the test clip 10. It will be
appreciated that other connector mechanisms 14 may be used in accordance
with the invention preferably to provide the desired relative movement of
the body portions 11, 12 for installing and removing the test clip with
respect to an integrated circuit package 22 or other device and preferably
also for resiliently holding the test clip to such device.
In the preferred embodiment and best mode of the invention, the
leaf springs 24, 25 of the connector mechanism 14 are in or approximately in
the plane of the cable 15. This still further contributes to the ability to
minimize the profile height of the test clip 10. Such minimum height tends
to reduce antenna effect. However, if desired, the height of the upper
bodies 16, 17 may be raised slightly to accomodate a sheet-like metal spring
totally across the top of the cable 15 between the body portions 12, 13 or
below the cable between the cable and the integrated circuit package, for
example, thus providing a shielding function and further minimizing
undesirable antenna effect.
The contacts 13, are intended to be relatively compliant to
accomodate effective electrical connections with leads of integrated
circuits or other devices in which the actual lead positions are not always
located according to specification. As is seen in Figs. 1 through 7, the
contacts are of a configuration that provides a multiplicity of functions.
Importantly, each contact 13 is intended to provide an electrical connection
between a respective conductor 30 of the cable 15 and a respective lead 31
of the integrated circuit package 22, For this purpose, each contact 13 has
a mounting portion 32 and a contacting portion 33 for respectively
connecting electrically with such conductor 30 and lead 31. The cable 15 is
secured in the body portions 11, 12 to extend generally parallel to a printed
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circuit board or the like onto which the integrated circuit package 22 may
be mounted, thereby minimizing the space required for the cable, especially
by avoiding any need to bend or to twist the cable when bringing it out from
the test clip 10 and integrated circuit 22. This arrangement minimizes
space requirements for the test clip 10 and cable 15 and also minimizes
potential damage to the cable and/or other components while further
minimizing possible antenna effect due to a distorted cable.
To enable such cable 15 to be brought out in parallel to such a
prined circuit board, while minimizing the height of the body portions 11,
12, the mounting portion 32 of each contact 13 extends in a generally
parallel direction with the conductors 30 and cable. Each mounting portion
is connected at a junction 34 to a respective conductor 30 by soldered
connection thereto. At the end of the contact mounting portion is a
downwardly turned or bent tab 35, the purpose of which is to help secure or
anchor the contact in the molded material of the respective body portion 11,
12.
The contacting portion 33 of each contact 13 preferably is
smoothly curved or bowed over the major extent thereof to facilitate
smooth sliding, wiping and bending thereof with respect to a lead 31 as the
test clip 10 is installed or removed with respect to an integrated circuit
package 22. Such bending preferably ordinarily would be within the resilient
limits or elastic limits of the contacting portion 33 to avoid overstressing
the contact to an undesirable permanent shape, such as one that would not
assure the desired wiping and resilient engagement with a lead 22.
Preferably each contacting portion 33 is recessed below the height of each
of the relatively adjacent separators 20 to protect the contacting portions
from external stresses, contamination, and the like before and during
installation on an integrated circuit 22; in Fig. 1 the curvature of the
contacting portions 33 is emphasized for facility of illustration. At the
remote end of the contacting portion 33 is an inwardly, i.e. toward the
center of the radius of curvature of the contacting portion, bent tab 36.
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The tab 36 functions to avoid a sharp end at the end of the contacting
portion which could damage a lead 22 or a user of the test clip 10. The tab
36 also protects the contact 13 itself by preventing the end of the
contacting portion from biting into a lead and becoming lodged therein so as
to cause a permanent bending distortion of the contact 13 on continued
application of force thereto during installation on an integrated circuit
package 22.
A curved intermediate portion 37 of each contact 13 joins the
mounting portion 32 and the contacting portion 33. The intermediate
portion 37 maintains the continuity of curvature of the contacting portion
33, while providing a smooth transition to the mounting portion, which
extends generally perpendicularly with respect to the major directional
extent of the contacting portion and in any event generally in parallel with
the conductors 30 and cable 15. Moreover, importantly the curved
intermediate portion cooperates with a curved wall surface 40 of the body
portion 11 or 12 between relatively adjacent pairs of separators to allow
bending of the contact 13 minimizing stress concentrations and preventing
overstressing thereof. The wall surface 40 is curved to an extent that
permits relatively free bending of the contact 13 contacting portion 33 and,
particularly, the intermediate portion 37 during normal installation and
removal of the test clip 10 relative to an integrated circuit package 22
without overstressing the contacts beyond their elastic limit. The body
portions also have back-up wall surfaces 41 extending from and located
below the curved wall surfaces 40, recessed relative to the separators 20,
and positioned behind the respective contacting portions 33 of the contacts
to limit the maximum bending of the contacts to prevent possible
overstressing during use, including the aforesaid installation and/or removal.
The permissible bending of the contacts 13 and the limiting of such bending
by the walls 40, 41 provides a relatively high degree of contact compliance.
The radius or curved wall 40 allows a relatively large deflection of the
contact 13 for maximum movement of the contacting portion 33 toward or
away from a lead 31, for example, before the contacting portion bottoms
out against the wall 41.
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Referring particularly to Fig. 7, the cable lS preferably is a flat
ribbon type cable having plural electrical conductors 30 arrRnged in parallel
positional relation and held so and in electrical isolation by the cable
insulation 49. According to the preferred embodiment and best mode of the
present invention, such cable 15 is that known as trasmission line cable
intended for high speed signal transmission; and in such case each signal
conductor 30s is bounded on both sides thereof by respective ground
conductors 30g. Other types of flat ribbon cable or other cable also may be
used, though.
To form a junction connection 34 between a respective
conductor, such as one of the signal conductors 30s, and the mounting
portion 32 of a contact 13, a portion of the insulation 49 is removed at an
area 50 or Sl of the cable to expose the conductors, and the particular
conductor intended for such connection is deformed slightly downwardly out
of the major planar, linear or axial extent of the cable ~nd conductors
therein, for example, as is shown at the deformed conductor portion 30d.
The junction connection 34 is completed by soldering together the deformed
conductor portion 30d and the contact mounting portion 32, thereby forming
a secure mechanical and electrical connection thereof. Therefore, those
conductors 30 that are to be connected to respective contacts 13 carried in
the body portion 11 are bent or deformed down at the area 50 of the cable
where the body portion 11 is to be molded to form such-respective junction
connections 34; and for those conductors 30 intended to form junctions with
contacts 13 carried in the body portion 12, they are so deformed at the area
51 of the cable lS where the body portion 12 is to be molded. In this manner
relatively close packing of the contacts and the conductors can be
accomplished, and the contact spacing can be such that will conform to the
spacing of the leads of the integrated circuit package 22, as will be
described further below. Those conductors 30, such as ground conductors
30g, which are not to be connected to a respective contact at one of the
body portions 11, 12 are not so downwardly deformed and, therefore, are
maintained out of connection with respective contacts.
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After the respective junctions 34 have been so formed between
respective contacts and conductors, the respective body portions 11, 12 are
molded directly to and about such junctions, part of the cable insulation 49
and exposed conductors at such areas 50, 51 of the cable where the
insulation had been removed, and part of the contacts 13. The body portions
11, 12 form an hermetic seal about the junctions to prevent air and moisture
from reaching the same and causing any corrosive or electrolytic action that
could reduce the efficiency of the electrical connection thereof. The cable,
junctions and contacts, then, become an integral part of the body portion,
thus forming a strong mechanical structure with high electrical connection
and insulation integrity. In one embodiment, during such molding the
insulation of the cable may form a chemical bond with the molding material,
preferably of plastic or plastic-like material, of the body portion for strain
relief. However, due to the deformation of the conductors, the mechanical
connection thereof to respective contacts, and the molding of the body
portions about such deformed conductors and such junctions, effective strain
relief also is achieved thereby.
Turning now to Figs. 8 and 9, parts of the low profile test clip 10
are shown in position relative to each other ready for molding thereabout
the respective body portions 11, 12. At areas 50, 51 insulation 49 has been
removed to expose the parallel conductors 30 in the cable 15. Such
conductors include ground conductors 30g and signal conductors 30s. At the
upper portion of Fig. 8 the preferred form of the cable conductor structure
is illustrated; such conductor configuration includes a ground conductor 30g
at the edge of the cable, a signal conductor 30s adjacent and parallel to such
ground conductor, a pair of ground conductors 30g parallel to and spaced
away from the first-mentioned signal conductor, the next signal conductor,
etc., whereby a separate pair of ground conductors is provided for each
signal conductor in the cable. At the lower two-thirds of the cable shown in
Fig. 8, only a single ground conductor is shown between adjacent signal
conductors in order to avoid cluttering the drawing, but it will be
appreciated that such illustrated single ground conductors may represent a
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pair thereof in the fashion shown on the upper portion of Fig. 8. It will be
appreciated, though, that other conductor and cable configurations may be
employed in accordance with the present invention.
As is seen in Figs. 8 and 9, the contacts 13 are formed by cutting
the same, for example die cutting, from one of two sheets of material 52,
53, whereby respective pluralities of contacts 13 are supported by
respective carrier strips 54, 55. The sheets 52, 53 also preferably are bent
to form the tabs 35 and respective handles 56, 57, which facilitate proper
placement of the contacts 13 relative to the conductors 30 during the
soldering operation to form the junctions 34 and during the molding
operation to form the body portions 11, 12. Each of the contacts 13 has a
connecting end 58 forming at least part of the mounting portion 32. The
connecting end and the other parts of the contact 13 may be of the same or
different lateral widths, relatively the same being preferred. However, in
the illustrated embodiment the connecting end 58 is of smaller width than
other portions of the contact to facilitate close packing without short
circuits relative to the conductors 30. Each contact 13, then, is shown with
a relatively wider portion 59 (Fig. 8) to maximize the surface area of the
intermediate portion 37 and contacting portion 33 for strength, durability,
compliance and available area for engagement with a lead 31 of an
integrated circuit 22. The connecting end 58 is offset from the contacting
portion 59 to expose an edge surface 60 of the contact essentially out of the
plane (as it is seen in Fig. 8) beyond the edge of portion 59, and such edge
surface 60 has a vector component that faces the direction of and opposes
forces that would tend to pull the contact, say in either direction
approximately parallel to the direction of the cable 15, from the molded
body portion. Thus, the edge surface 60 may be cooperative with the
molded material of a body portion 11, 12 further to enhance strain relief for
the contact 13 and for the junction 34 of the contact and conductor with
respect to a given body portion 11, 12.
Preferably the sheets 52, 53 are identical, but being used in
paired opposition with the hand!es 56, 57 abutting earh other, the
.
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16
connecting ends 58 of the sheets 54, 55 effectively are displaced,
respectively, in opposite directions. Therefore, an opposite pair of contacts,
such as those identified 13a, 13b, of respective sheets 52, 53 are in parallel
opposed alignment with each other for engaging the paired opposed parallel
leads 31 on opposite sides of an integrated circuit package 22 while the
respective connecting ends 58 of such paired opposite contacts 13a, 13b are
offset to form electrical junctions 34 with relatively adjacent signal
conductors 30s. Thus, for example, the signal conductor 30s, which also is
identified by the reference numeral 70, is aligned for electrical connection
with the contact 13b; such conductor 70 also continues to pass through the
cable, e.g. to the left hand direction as is seen in Fig. 8, but does not align
with the connecting end 58 of the contact 13a. However, the signal
conductor 30s identified by reference numeral 71, which is the next signal
conductor adjacent the one identified by reference numeral 70, passes
through the cable for alignment with the connecting end of the contact 13a
but without engaging the connecting end 58 of the contact 13b, and so on.
Other signal conductors 72 throught 75 are similarly represented in Fig. 8
aligned for connection with respective contacts 13 carried by the respective
carrier strips 54, 55.
Those conductors 30 which are intended to form junctions 34
with the narrow connecting ends 58 of respective contacts 13 are deformed
downward out of the major planar or axial extent of the conductors, for
example, as is seen at conductors 74 and 75 in Fig. 9. To facilitate forming
soldered connections at such junctions 34, the connecting ends 58 may have
a coating of solder already placed thereon prior to assembly in the manner
shown in Figs. 8 and 9. After such assembly, heat, hot vapor, or other
means may be 0mployed to re-flow such solder to form soldered connections
of respective contacts and conductors at junctions 34.
It will be appreciated that the described narrowing of the
contact ends 58, the off-setting thereof, and the conductor deformation to
form respective junctions especially facilitates close packing of the
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contacts 13 in the test clip 10 while desired electricPl isolation
requirements are maintained.
If desired, all or selected ones of the ground conductors 30g may
be electrically connected in common using a wire 80 as a grounding bus
therefor. Such wire 80 is adjacent the cable area 50 intended for enclosure
in the body portion 11, and at such area it will be necessary to deform out of
the plane of the wire bus 80 all of the signal conductors to avoid short
circuiting thereof to ground. However, due to the offset configuration of
the narrow connecting ends 58 of the contacts 13, the downward deforming
of those signal conductors which are not intended to be connected to
contacts supported on the carrier strip 54 will not engage such contacts
thereby maintaining desired electrical isolation. (The molded body portion
about the junctions 34, contact mounting portions 32 and conductors 30 also
helps maintain such isolation.) If desired, the ground conductors 30g may be
deformed upwardly out of the major plane or axial extent thereof to engage
the ground bus wire 80 in further isolation from all of the signal conductors
30s. The ground bus wire 80 may be pre-coated with solder that may be re-
flowed using conventional techniques, such as heat, vapor, etc., to form
soldered connections with the respective ground conductors 30g.
Additionally, the connector mechanism 14, specifically the individual leaf
springs 24, 25 thereof, also may be mechanically and electrically attached
to the wire bus 80, for example by connecting the wire through holes in such
springs, as is shown at 81, 82 in Fig. 8, thus further enchancing the overall
ground plane isolation, noise shielding and antenna effect minimization
characteristics of the test clip 10.
After the parts illustrated in Figs. 8 and 9 have been assembled
in the manner illustrated therein and described above, the body portions 11,
12 may be directly molded thereto. The body portions preferably are of
electrically non-conductive plastic or plastic-like material and are molded
using a plastic injection molding process. Such body portions form hermetic
seals about the respective junctions 34, preferably integrally bond to the
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18
cable insulation 50, and position the respective wall surfaces 40, 41 relative
to the exposed portions of the contacts 13, such as the contacting portion 33
and intermediate portion 37 thereof while the mounting portion 32 of each
contact is secured in the molded body portion. After such molding, the
handles 56, 57 of the respective contact carrier strips 54, 55 may be bent in
a downward rotating fashion to bend the contact intermediate and
contacting portions to the shape illustrated generally in Figs. 1, 2, 4, and 7.
The carriers 54, 55 then may be broken away or off from the contacts 13 at
a break-away line 83, 84, which muy be scored into the surface of the sheets
52, 53 during the formation thereof, thereby simultaneously forming the
tabs 36 and electrically separating the individual contacts 13 from each
other. The actual shapes of the wall surfaces 40, 41, and the manner in
which the bending forces are applied to the contacts via the carrier strips
54, 55 will determine the shapes or curvatures of the contact intermediate
and contacting portions 37, 33. PreferaMy such portions are curved in the
manner shown. However, it may be the case that the contacting portion has
more a linear extent than a curved one, and this configuration may be
acceptable as long as the overall formation is such that the test clip can be
inserted and removed with respect to the leads of an integrated circuit
package making good electrical connection with such leads without
damaging the same or the contacts (tabs 36 help avoid the possibility of such
damage).
It will be appreciated that the test clip 10 may be located at or
near an end portion of the cable 15 or at a portion of the cable intermediate
the ends thereof. The remainder of the cable may be a "brought out" to
another device for electrical connection thereto, such as a test device,
signal injector, etc. Moreover, one or more test clips 10 may be formed on
a single cable 15 at respective axial positions therealong to effect an
interconnection via the cable of a plurality of integrated circuits or the like,whereby such test clips and cable also may form a parallel bus or daisy chain
type device. Such an arrangement is shown in Fig. 10.
~'' .,
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19
Referring to Figs. 11 through 13, a handle 90 for installing and
removing the test clip 10 with respect to an integrated circuit package 22
includes a pair of handle grips 91, 92 which are preferably connected by a
resilient strap 93. The strap 93 facilitates manipulation of the handle 90
and, in particular, used thereof with respect to the test clip 10, for example
by effecting the resilient biasing of the grips 91, 92 $o the positions shown
when not connected to a test clip. The strap 93 may be eliminated and the
individual grips 91, 92 used without the strap, although such use would be
more awkward than with the strap. The strap 93 may be secured to the
grips 91, 92 by molding therewithin.
Each of the grips 91, 92 has a pair of elongate arms 93, 94 that
support jaw-like portions 95, 96 at the ends thereof. Each jaw has a
configuration providing for a slotted area 97 formed between a lower tooth
98 and an upper surface 99, and such jaws preferably are located only at
respective opposite lateral ends of the grips 91, 92 (as is seen in Fig. 11).
The jaws fit over the respective lateral edges 100, 101 (Fig. 3) of each body
portion 11, 12 to grip the same securely. To that end the slots 97 preferably
are approximately just slightly larger than the height of the respective
upper bodies 16, 17 (Fig. 1), whereby the handle grips 91, 92 effectively
become mechanical extensions of the body portions 11, 12 to form a close
fit therewith. Since the jaws are at the lateral ends of the grips 91, 92,
when such grips are-placed on the body portions 11, 12, such jaws align
substantially directly with the leaf springs 24, 25. Accordingly, as force is
applied by the handles to the body portions tending to pivot, twist or rotate
the same, thuQ resiliently distorting the leaf springs 24, 25, substantially
direct force will be applied to such leaf springs while effecting a
compression of the proximate parts of the body portions 11, 12 and
minimizing other forces and stresses to such body portions, thereby
maintaining the physical integrity of the test clip during such force
application.
Using the handle 90 to install the test clip 10 on an integrated
circuit package, the jaws 95, 96 are placed on the test clip in the manner
illustrated in Fig. 12. Force is applied to the arms 93, 94 tending to move
j.
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them toward each other to rotate or to pivot the body portions 11, 12
enlarging or opening the space between the teeth 21 of the opposed body
portions. The space between opposed contacts 13 also is opened, and the
test clip 10 may be inserted downward onto an integrated circuit package,
for example in the manner illustrated in Figs. 2 and 13. During such
insertion or installation, the contacts 13 engage leads of the integrated
circuit, preferably resiliently deform with respect to such leads, and wipe or
rub against such leads to clean the interengaged surfaces and to enhance
electrical connection. (Alternatively, the contacts may not be resiliently
biased against the leads until the force applied to the handle arms 93, 94 is
released.)
After such insertion or installation, the force applied to the arms
93, 94 tending to force the same together is released, whereupon the
resilient connector mechanism 14 will tend to return the body portions 11,
12 back to original position closing the space between the teeth 21. The
teeth 21 then preferably engage and grip the side wall of the integrated
circuit package holding the test clip 10 thereto while the contacting
portions 33 of the contacts 13 engage respective leads 31 of the integrated
circuit package. After such installation, the handle 90 may be removed
from the test clip 10. To remove the test clip 10 from an integrated circuit
package, the handle may be re-connected to the test clip. Force applied to
the arms 93, 94 tending to press the same toward each other effects the
desired pivoting and space-opening effect of the body portion 11, 12
facilitating the freeing and removing of the test clip 10 from the integrated
circuit.
In view of the foregoing, it will be appreciated that low profile
test clip 10 of the invention may be used to connect the conductors of a
cable to the leads of an integrated circuit package, for example, while such
connection is easily maintained in a close-packed environment, the test clip
having minimum space requirements, and the test clip also minimizes
antenna effect.
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