Note: Descriptions are shown in the official language in which they were submitted.
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EXTRACTOR TOOL FOR PRI~TED CIRCUIT C~RDS
FIELD O~ T~IE INVEMT10~
The present invention relates to a tool designed to
facilitate the extraction of a printed circuit card having
front edge connectors from a holder.
BACK~ROUND OF THE INVENTIO~
Today, printed circuit cards are frequently
assembled in a holder rack having the shape of an open
topped box whose side walls form tracks for the guidance
of cards into and out of their assembled position. Etched
terminal tabs on a base strip or block of each board fit
into a socket having co-acting contacts to complete a
connection to an external backplane circuit. In practice,
the track forming side walls may be horizontally disposed,
with the contact bearing sockets arranged on the upright
rear wall. In some applications the cards also include
terminal contact tabs on the front edge of each board for
connecting to cabling having suitably formed co-acting
contact jacks or sockets.
The extraction of such printed circuit cards from
their holder is a somewhat delicate operation since the
abrupt reduction of frictional resistance upon
disengagement of the backplane connectors may lead to an
accelerated withdrawal motion deviating from the line of
the card track and thus impose bending stresses which
could damage the printed circuits. A further aggravating
condition is the presence of the front edge cable
connectors which prevent the placement of a handle or
other devices to facilitate their withdrawal. This
problem is perceptively increased as the printed circuit
boards become larger which substantially increase the
extraction force required. Not only is this condition a
problem in
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the field but it is also encountered during production
and testing of assembled systems. Presently, many
printed circuit cards are equipped with magnetic strips
which must be scanned at various stages of production,
wherein during many of the production stages, the
card is located in the frame. For cards without front
edge connectors this is not a problem since the cards
are equipped with handles, and the magnetic strips
are located on the handles. Where so located it is
a simple matter to utilize a portable scanner without
removing the card from the file. In the case of front
edge connector cards, the magnetic strips are located
to the side of the connector. Therefore, to scan
the magnetic strips on the front edge connector card,
it must be partially extracted from the card file.
The only workable tool for the front edge card extrac-
tion was a pair of pliers. This method obviously
had the potential ~or card damage and further resulted
in injury to the wrists of the personnel performing
this operation.
Accordingly, a tool is required to properly
extract these boards. This tool must be compact,
simple to operate as well as human engineered to be
comfortably operated.
It therefore becomes an object of the present
invention to provide an improved economical tool of
the character described which facilitates the extrac-
tion of such printed circuit cards.
SUMMARY_OF THE INVENTION
The tool according to our invention has
been designed to work with holders of the type having
an open card cage construction. The holders have
top and bottom front card guides oriented in a hori-
zontal direction. The card guides also include trans-
verse slots which accept lateral edges of a printed
circuit card. The slots hold and guide the card to
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the connector f`ound in the rear of the holder. The
invention has been designed to be used with cards which
include front end connectors on -the front edge of -the cards.
These connectors have contact tabs at the front
edge of the card and are con-figured to match a co-acting
jack assembly normally terminating a cable. To ensure that
the cables do not become dislodged, a projec-ting tab i~
located on the printed circuit card such that a co-acting
catch on the cable jack engages this tab and locks it onto
the card.
The present invention utilizes this tab on the
printed circuit card and a cable jack frame without the
terminal contacting assembly to seize the card and thus
facilitate its withdrawal.
BRIEF_DESCRIPTION_OF_THh`_DRAWINGS
The invention may be readily understood through
reference to the following description in combination with
the drawings wherein:
Fig. 1 is a top view of a printed circùit card end
haviDg a front end connector.
Fig. 2 is also a top view of a cable connector
that is arranged to connect with the connector of the card.
Fig. 3 is a sectional view of cable connector on
the card taken along lines A-A of Fig. i, showing the
2~ position of the locking tab.
Fig. 4 is a plan view of the card puller used to
extract a card of the type illustrated from a card file.
Fig. 5 is a sectional view of the card puller
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taken along lines B-B of Flg. 4, ~howing the retaining tab
and associated release.
Fi. 6 is a partial side sectiorlal view o-P the
card puller and associated card shown prior to eDgagement.
Fig. 7 is a par-tial side sectional view of the
cable connector and the card showing the relative positions
during engagement.
Fig. 8 is a partial side sectional view of the
cable connector and card showing the relative positions
immediately a*ter engagement.
DESC~IPTION_OF THE P~EFEPRED ~MBODIMENT
Turning now to Fig. 1 there is shown the front
portion of a printed circuit card 101 having along the front
edge a multi-contact connector assembly
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102 with a plurality of contact pins such as 103.
This connector may typically be one such as that
manufactured by GTE Sylvania as part No. 7900-1337-
001. The molded body of this connector assembly
includes on its top surface a number of projecting
tabs such as 104 onto which the cable connector latches.
Also visible are a number of fastener~s 106 used to
hold the connector assembly to the printed circuit
board 101, and a strip of magnetic tape used during
production and quality assurance operations.
Facing the circuit board 101 in Fig. 2 are
two cable terminations such as the one labeled 110.
This connector jack may typically be one such as manu-
factured by GTE Sylvania as part No. 7900-1303. In
most instances these cables are used only in the final
field assemblies of an entire system and are not part
of the local wiring of a piece of equipment. Not
visible in this view, under the protective tabs 111
is a jack assembly arranged to mate with the contact
pins 103 of the card. A releasable locking catch
112 is shown which co-acts with a member such as tab
104 to retain the cable onto the card.
The tool of the present invention arranged
to extract the card assembly of Fig. 1 is shown in
Fig. 4. As is readily apparent it includes two cable
terminating shells such as shown in Fig. 2 and labeled
110~ The cable terminating jacks are not included
in the puller assembly. These two cable terminating
jack shells are fastened together at the end 113
through which the cable would normally enter, by a
handle 114 and fasteners llS. A plate 116 maintains
the two shells 110 in alignment and holds the two
shells together with fasteners 117. The latch 112
is better shown in the sectional view Fig. 5 drawn
along line B-B of Fig. 4. Here a generally "U" shaped
portion extends beyond the body of the connector shell
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and has an internally projec-ting tongue L2Z, this tongue at
it9 other surface has a cut away por-tion leaving a de-tent
surface 123. This portion pro,jects beyond the tab 104 when
this assembly is inserted over the projec-t-ing connector pins
o~ assembly 102. A laterally slidable release 118 is also
mounted on the connector shell. This release includes a
portion 121 which when pressure is applied a-t surface 124
advances tongue 122 to lift it away ~rom -the tab member 104.
To keep release 118 in its normal unengaged position a
re~ilient finger 120 is biased against a pin 119 mounted in
the body of the connector shell and projects into the path
of the finger 120,
Re~erring now to Figures 6, 7 and 8, the card
puller is inserted into the front edge connector on the card
until the latches of both cable connectors assemblies engage
the tabs such as 104, Once both latches are engaged, the
card puller is locked onto the card. Moderate pressure on
the card puller handle at this time will extract the card
from the file. The card can be reinserted into the file by
applying a pressure on the handle in the reverse direction
of that applied in pulling the card. The card puller is
then released by pressing in on the release slide 118. The
card puller has no terminal pin modules in the cable cover
shells, and there is no danger of damaging the connector
pins on the -front edge of the card or the card itself.
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