Note: Descriptions are shown in the official language in which they were submitted.
is invention relates to oonnectors for printed circuit
boards.
More particularly, the invention relates to connectors for
printed circuit boards, comprising: a case having a groove into which a
printed circuit board can be introduced by cne of its edges; a plurality
of resiliently deformable contact members which are orientated
transversely with respect of the length of the groove and are each
equipped with a movable end and a fixed end which is held in a
substantially invariable position and shape by the ottom of the case;
and a control member mounted for rotation on the case to cause
alternately the opening and closing of the contact members which are
; situated at the same side of the mean plane of the groove in the case,
which members, on closing, each oome to touch, with an æ tive region
situated between the movable and fixed ends, with a suitable resilient
for oe , conducting aonnection tracks carried by the board to be connected
and ending transversely at the side of the board adjacent to the groove,
when the board has been introduced into the oonnector and the oontact
members thereof have been closed.
For a long time, an effort has been made to solve the
problem caused by the need for "opening" of the contact members just
before and during the introduction of any board into a oonnection device
twhich generally oomprises a plurality of connectors) and just before
and during the extraction of said board from the device, in other words
the proble~ of renoving the active regions of the contact members from
the volume then swept by this board so as to render the force necessary
for the introduction or the extraction of the board substantially zero
and so to p~otect the probective coverings of both the aontact members
of the connector or connectors and the conducting connection tracks of
the boards, from any wear by friction. Of aourse, it is essential, once
the board has reached its working position, for the contact n~bers to
nclose~, that is to say to aome to bear resiliently with their active
regions on the corresponding connection tracks of the board, which
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tracks are generally-provided on both sides of the board.
In his Canadian patent application No. 248,530
of the 16 March, 1976, the Applicant has already described
a mechanism which uses, not the rotation but the transla-
tion of a control member and which acts on the resilient
contact members of the connector or connectors, alter-
natel~ in the opening sense and in the closing sense.
As a result of this alternating control mechanism, the
operator is thus assured both of the opening of all the
contact members, just before and during the introduction
or the extraction of the board, and of their closing with
a suitable resilient force, once the board has reached its
working position. In French Certificate of addition, -
serial number 73,723 issued as #1,174,063, the Applicant
has also described a mechanism which uses the rotation
of a control member but which is adapted in such a manner
as to eliminate any sliding friction; the rotational
movement of this control member is caused directly by
the introduction and extraction movement of the board.
The object of the invention is to create a novel
connector which not only fulfils the same functions as that
described in the above-mentioned patent application, but
also makes the self-cleaning more effective, that is to
say an automatic mutual wiping of the conducting connection
tracks and of the active regions of the contact members,
on the closing of the latter. "Wiping" is here understood
to mean a relative sliding which is sufficient to eliminate
the dust liable to hamper the transmission of low voltage
signals between said active regions and conduct~ng tracks,
but insufficient to cause the wear by friction of the above-
- mentioned protective coverings. It is likewise an object
~.i"
. of the inYention to reduce the distance, and consequently
the durat~on of transfer o the electric signals, bet~een
the act~ve reglon of each contact member and lts fixed end.
Preferablr, moreover, it is an ob~ect of the invention
to adapt the connectors so that their contact members can
be removed and re-inserted or replaced indiv~dually.
According to the invention there is provided a
connector for printed circuit boards, comprising: a case
having a groove into which a printed CiTCUit board can be
introduced by one of its edges; a plurality of resiliently
deformable contact members, each disposed transversely of
the length of the groove and each having a movable end,
and a fixed end retained in the bottom of the case; and
a control member rotatably mounted on the case to effect -~
movement of the contact members between open and closed
positions, and situated to the same side of the median
plane of the groove in the case as the corresponding contact
- members, which members each have an active region situated
between the movable and fixed ends and serving in the
closed position resiliently to contact a conducting
connection track on a board inserted in the groove and at .
the side of the board adjacent to the contact members,
characterised in that each contact member is attached b~
its movable end to the control member with respect to which
it describes approximately one half-turn and that each
contact member comprises between its movable and fixed
ends a first portion and a second portion, the first
portion being located between the movable end and the
active region and being less flexible than the second
portion ~hich is located between the acti~e region and the
fixed end, ~hereb~ self-cleaning of the conducting tracks
of the board and of the acti~e regions of the contact
members is facilitated on movement of the members from
~, ~ , ' .
open to closed positlons.
In this manner, when, starting rom the open position,
th.e control member is caused to turn in the direction which
tends to reduce the angle of winding of each contact member
round thi.s control member, the radial distance (in relation
to thi.s latter member) of the active region is at first
caused to increase until this region comes to touch the
conducting connection track which is associated therewith.
Th.en, because of the differences in flexibility, the first
portion continues to be displaced in the same direction,
causing the acti~e region to slide along the conducting
connection track, ~hich arises because the deformation to
which the contact member is sub;ected occurs mainly in
its second portion.
Several solutions mar be adopted within the scope of
the in~ention in order that the two portions of each
contact member ma~ haYe different flexibilities; in
particular, the cross sectional area of the first portion
may~be greater than that of the second portion, or the
first porti~n may have a continuous longitudinal development
and the second portion a longitudinal development which
is made discontinuous by a loop, a backward bend or any
other incipient local deformation, or the first portion
may have a cross section such that the portion has a
greater mechanical stiffness than that of the second portion.
Needless to say, these three solutions may be combined with
one another in any manner.
According to an advantageous construction, the control
member consi~ts of a solid rod of insulating material which
i5 pro~ided ~th a radial slot at the location o each of
the contact ~embers relatiYe to the axis of the rod, the
morable end of each contact member being inserted in the
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co~responding slot.
~ n this latter case, in order to ~er~it the removal
of the contact me~bers, the ~oYable end of each contact
; member is engaged ~reel~ in the radial slot in the rotary
~ember; the fixed end Is engaged freelr in a slot
extend~ng through the bottom of the case, in whIch slot
it is held by removable means; and the fixed end and, in
the open position, the movable end are disposed in planes
perpendicular to the plane in which the bottom of the case
is disposed. In this manner, after the control member has
been placed in the opening position and the fixed end of
the contact ~ember to be removed has been released, the mem-
ber can be extracted b~ pulling it perpendicularly to the
bottom of the case, in the direction which moves it away
from this bottom. The reinsertion of the contact member
in question OT insertion of a new contact member is effected
br repeating the same operations in the reverse sense.
The invention therefore contemplates a connector for
printed circuit boards, comprising: a case having a slot
into ~hich a printed circuit board can be introduced by
one of its edges and with zero insertion resistance; a
plurality of resilientlr deformable contact members movable
between open and closed positions independently of circuit
board insertion and removal and spaced at intervals along
said slot, each of said deformable contact members having
a movable first captured end and a fixed second captured
end which is retained in the bottom of said case; and
control members rotatablr mounted relative to said case
to effect mo~ement of saad contact members between open
and closed pos~tlons and sltuated to the same side of the
median plane of s-ald slot in said case as the corresponding
contact members operated therebr, saàd contact members each
having an acti~e region situated between said movable and
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/C.P:'9
fixed captured ends and serving in said closed position
first to contact linearly a conducting track on the board
Inserted in said slot, said active reg~on then forming a
sliding connection with sald track and thereafter deformable
to $orm a surface connection with said conducting track at
the side of said board adjacent the respective contact
members, each said contact member being attached by its
movable captured end to said control member whereby the
captured end o said contact member describes a partial
rotational movement as the arcuate active region is deformed
into flat surface contact with the conducting track on said
~ board, each such contact member comprising a first portion
- and a second portion, said first portion being located
bet~een said movable captured end and said active region and
being less flexible than said second portion, which is
located bet~een said active region and said fixed end
~hereby self cleaning occurs by sliding of the active
region against the confronting surface of said conducting
tracks of the board as the respective contact members
are moved from said open to said closed positions.
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The invention will now be explained in more detail with
reference to the accompanying drawings which illustrate several
embodiment~ thereof.
~ igure 1, of the~e d swings, showg, in diagTammatic
perspective, a connector for printed circuit boards, according to
a first embodiment of the invention~ the upper portion of the Figure
illust sting the position for open;ng a contact member and the lower
portion the position for closlng another contact member.
Figures 2, 3 and 4 illustrate, with cross sections, the
position for opening, an intermediate position and the position for
closLng the contact member of the connector of Figure 1.
Figure 5 illustrates the operation of dismounting the contact
member of ~igures 2 to 4.
Figure 6 shows, in perspective, a contact member accor~;ng to
a second embodiment of the invention, and its rotary control member.
~ gures 7 to 9 illustrate, in a similar manner to Figures 2
to 4, three positions of the contact member of Figure 6.
Figure 10 shows, in perspective, a contact member according
to a third embodiment of the invention, and its rotary control member.
Figures 11 to 13 illustrate, in a similar manner to Figures
2 to 4, three positions of the contact member of Figure 10.
Figures 14 to 16 show, in perspective, on a larger scale,
three possible forms of a contact member for use in the embodiment of
Figures 10 to 13.
Finally, Figure 17 shows a modification of the embodiment of
Figures 1 to 5.
~ he connector illustrated diagrammatically in Figure 1
comprises a case 1 which is made of insulating material and which
comprises a bottom 1a and two flanges 1b. ~hus this case has a ~-
section which leaves free a cent sl groove 2 (see Figures 2 to 5).
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~ , ..
:~)b~
A printed circuit board 3 can be introduced ingide this groove 2, by
one Or its edges. The connector further comprises, at each side of
the~median plane P of the groove 2, a plurality of resiliently
deformable contact members 4 which are diBpo9ed transversely of the
length of the groove 2 and are each equipped with a movable end 4a
and a fixed end 4b. ~he fixed end 4b is held in a substantially
invariable position and shape by the bottom 1a of the case 1. The
connector further comprises two control members 5, disposed in a
substantially symmetrical manner with reæpect to the median plane P of
the groove 2 (that is to say with respect to the median plane of the
board 3 placed in the connector). lhese members 5 are adapted to
cause alternately the opening (see top of Figure 1 and Figure 2) and
the closing (see bottom of Figure 1 and Figure 4) of the contact members
4 which are situated at the same side of the plane P. In this manner,
the contact members 4 each come to touch, with an active region 4c (see
~igures 2 to 4) situated between the ends 4a and 4b, conducting
connection tracks 6 carried by the board 3 and ending at the side of the
board adjacent to the groove 2 when the board 3 has been introduced into
the connector and the contact members 4 have been closed.
h contact member 4 is attached by its movable end 4a to the
rotary control member 5 round which it describes approximately one half-
turn (or half-turn of a helix) and it is adapted to have, in its
deform~ble portion comprised between its ends 4~ and 4~, less flexibility
in its first portion 7 comprised between the movable end 4a and the
active region 4c than in its second portion 8 comprised between the
active region 4c and the fixed end 4b (see Figure 2).
According to the embodiment in Figures 1 to 5, each contact
member 4 is formed by a metal strip curved in such a manner that the
generatrices of its curved surface are parallel to the axis of the
control member 5. The portion 7 has a continuous longitudinal develop-
ment, in the form of a spiral, while the portion 8 has a longitudinal
development which is rendered discontinuous
~ 3
.
by an S-shaped deformation 9 which ia arranged between the fixed end
4~ and the active region 4c.
~ he control member 5 consists of a solid rod of insulating
material which ig provided with a radial slot or groove 10 (see
Figure 5) at the position of each of th~ contact members 4, the
movable end 4a of which i8 inserted in this slot. The slots 10 are
preferably fo~med on cylindrical portions 5a having a larger diameter
th n the cylindrical portions 5b forming trunnions inside the flanges
1b of the case. In order that the rod may be introduced into these
flanges 1b, despite the presence of the cylindrical portions 5a, the
n anges may be divided by separation surfaces 11 passing through the
axi8 of the control members 5. ~he latter are equipped with operating
levers (not shown) which emerge at the end of the case 1.
~ t the position of each member 4, the flanges 1b have a slot
12 which is orientated parallel to this flange and is open towards the
plane P. The width of the slots 12 iB only slightly greater than the
-thickness of the contact members 4. Each slot 12 is bounded by the
lateral faces of two teeth 13 of rectangular section. ~etween the
teeth 13 of the opposite flanges 1b there is a gap sufficient to receive
the edge of the board 3.
The vable end 4a of each contact member 4 is engaged freely
in the radial groove 10 in the control member 5 which iB allocated
thereto. Similarly, the fixed end 4b is engaged freely in a slot or
groove 14 (Figure 5) traversing the bottom 1a of the case 1 against
which it is held by removable means. According to the form of
embodiment in ~igures 1 to 5, the groove 14 has a width less than the
normal width of the contact member 4, the fixed end 4b of which iB
narrowed, form;ng a shoulder 15, 80 as to be able to penetrate into
the groove 14. This limits the driving in of this end 4b which can
be held in position by twisting, as shown at 4d, the tail of the
contact member, that i8 to say the portion of its fixed end 4~ which
passes through the bottom 1a of the case 1. As Figures 1 (top), 2 and
~ 10 ~ r
5 show, the fixed end 4b and, in the open pOsition, the movable end
4~ are orientated perpendicular to the bottom 1a. Finally, the
case 1 is open, at the side oppo8ite to the bottom 1a (that is to
say towardg the left of Figures 1 to 5), at the level of each
contact member 4.
Thus a connector is obtained, the assembly and mode of
operation of which are as follows: first the rotary members 5 are
placed in position, after which each fl~ge 1b is assembled along
its separation plane 11. Then, with the control members 5 in their
opening position, each contact member 4 is introduced, bringing it
towards the bottom 1a parallel to the plane P, in the opposite
direction to that of the arrow in ~igure 5. ~his causes the movable
end 4~ to enter the groove 10 in the corresponding control member 5
and the fixed end 4b to enter the groove 14 in the bottom 1a. When
this end 4b is stopped by contact of the shoulder 15 with the inside
edge of the bottom 1a, its projecting portion is twisted as shown at
4~ in Figure 1. The contact member 4 is then in the position
illustrated in Figure 2. Gnce all the members 4 have been placed in
position connections can be made to their projecting portions or tails,
80 that the connector is ready for operation. ~he active region 4c is
withdrawn with respect to the location of the board 3. A board can
therefore be introduced without the contact members 4 scrapi~ or
rubbing the conducting t scks 6 of the boæ d 3, as can be seen from
Figure 2.
~ he upper control member 5 is now turned in the direction of
the arrow in Figures 2 to 4, that is to say in ~he direction which
tends to reduce the angle of winding of each contact member 4 round
the control member 5. Thus the radial distance of the active region
4~ is at first caused to increa~e until this comes to touch the
conducting track 6 which is associated thexewith, first of all at a
point Q (or more precisely along a generatrix perpendicular to the
plane of Figures 2 to 4 and passiRg through this point Q). This is the
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.~
4~
~ position illustrated in Pigure 3 ~here contact is
established, ~ithout .force, bet~een the contact members
4 and the tracks 6. The control membeT 5 continues to be
turned in the same d~rection. Because of the d~fferences
àn flexibilit~ between the portions 7 and 8, the first
port~on 7 continues to be displaced, caus~ng the actlve
region 4c to slide along the conducting track 6 while the
S-shaped portion 9 is subjected to a more pronounced
deformation. The result is, simultaneously, a sl~ding of
the point Q on the track 6 (as can be seen by comparison
between Figures 3 and 4), that is to say a self-cleaning
' of the contact surfaces, and a flattening of the active
region 4c agaInst the track 6, which im.proves the conditions
for the passage of electric current. Another feature which
improves these- conditions of passage lies in the short
length bat~een the active region 4c and the tail of the
contact member 4. Thus it is certain that all the members :~
4 contact the tracks 6 with a suitable resilient force
after eli~ination of the dust liable to hamper the passage
of current and contact over an appreciable area because
of the flattening of the active region.
In order to open the connector, that is to say in
order to withdra~ the contact members 4 with respect to
the tracks 6 of the printed circuit board 3, lt is suf~
ficient to cause the control member 5 to turn in the
opposite direction, which causes each contact member to
pass successively through the positions of Figures 3 and 2.
If it~is desired to check OT replace a member 4, it is
sufficient to dàsconnect ats tail, to untwist the twisted
portion 4d Csee Figure 13and to pull the contact member
in the direction of~ the arrow in Figure 5.
~ 12 -
i~
The form of the embodiment in Figures l to 5 is
i distinguished b~ the S-shaped permanent defo~mation 9
~hich.e.nds tangentlall~ at the fixed end 4b and at the
acti~e region 4c and which enhances defor~atàon parallel
to the plane P of the groove 2 in the portion 8 ha~ing
the greater ~lexlbilit~. The embodiment of Pigures 6 to
9 onl~ di~fers from the preceding one in the replacement
o the S-shaped permanent deformation 9 by a permanent
deformation 16 in the form of a boss which is more or
less 5ymmetrical with respect to a perpendicular to the
plane P. In this case, when the connector is closed
(successive passage through the positions of Figures 7, 8
and 9), the sides of the boss are pressed towards one
another, increasing the height of this boss, with the
same effect of sliding of the point Q and flattening of the
acti~e region 4c. Another difference in comparison with
the pre~ious embodiment consists in that the slot 14 in
which the fixed end 4b of the contact member 4 is engaged
is closer to the plane P to facilitate the passage of the
deformation 16 under the control member 5 during removal
(cf Figure 5) or replacement of the contact member 4.
According to the embodiment in Figures 10 to 13, the
contact member of which is illustrated on a larger scale
in Figure 15, the difference in flexibility between the
portion 7 and 8 is due to the fact that the cross section
of the first portion 7 has a larger surface than that of
the second portion 8. If a metal strip with a section of
0.80 x 0.40 mm is used, for example, it is possible to
provide cutouts at both sides to transform it, in the
reg~on of port~on 8, into a wire o square section 0.40
x Q.40~ or o rectangular section 0.30 x O.40 mm. The
cut-outs whlc~ are thus formed b~ cutt~ng awa~ so as to
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.
4~
reduce the section of the contact ~ember 4 locally are
designated b~ 17 in Figures lQ and 15. Th~s form of
e~bod~ent has the adYantage, ~n co~parison with the
pre~lous ones, of shortening the portion of the member 4
~hich is co~prised between the actl~e region 4c and the
tail b~ means of which the external connection is made.
Its operation às the same as that of t~e previous embodiments
and the deformation of the contact member 4 can be seen
from a comparison betwen Figures 11 ~open), 12 (coming
into contact through the point Q) and 13 (closed).
Part of a further form of contact member is illustrated
in Figure 14. According to this solution, the portion 7
with less flexibilitr has a cross section having a greater
mechanical strength than that of the portion 8. In this
case, the starting material may, for example, be a resilient
wire having a circular section with a diameter of 0.50 mm.
For the portion 8, the wire is flattened over a certain
length, as illustrated at 18, in order to obtain a flat
wire ha~ing a section 0.25 x 0.75 for example, the flat
wire being disposed in a plane parallel to the plane P,
in the connector. The deformation of the contact member
4 thus constituted is similar to that of the embodiment
of Figures 10 to 13,
In the contact member partly illustrated in Figure 16,
the difference in flexibility between the portions 7 and 8
is obtained as a result of the fact that the portion 7 has
a cross section having a greater mechanical strength than
that of the portion 8, bearing in mind the forces to which
the rotation o~ the control me~ber 5 subjects the contact
~e~ber 4. ~ a ~lat ~ire ls used as the starting material,
it is possible to obtain the portion 7 br locating the
contact me~ber in the case, ~ith the plane in which portion
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~)6 ~
7 i~ d~sposed perpendicular to the axis of the member 5,
and, by~t~sting th.e ~ire through 90 as indicated at
18 in Pigure 16, arrange the plane in which portion 8 is
disposed parallel to the axis of the member 5.
In order that all the possi~llities offered within the
scope o the invention may be better understood, a
modification of the embodiment in Figures 1 to 5 is
illustrated in Figure 17 which is distinguished by the
presence of a stiffening element 19 which is, for example,
soldered to the control member 5 and to the portion of the
contact member 4 closest to said member 5 to make this
portion substantially non-deformable. Another solution,
to make the portion 7 less flexible than portion 8, which
might be emplo~ed when portion 7 is for example circular
in cross-section, consists in threading on the portion 7
either a helical metal wire or a resiliently deformable
; sheath.
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