Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to multiple contact connectors in
which one member carrying a plurality of contacts is inserted into
another member also carrying a multiplicity of contacts, with
electrical contact occurring between the two sets of contacts. In
particular the invention relates to multiple contact connectors as are
used for connecting circuit boards to back planes and similar parts of
communications equipment. By zero insertion force is meant that
substantially no force is required to overcome frictional and
displacement loads as the two sets of contacts are moved into
position.
In operation, it is a general requirement that a minimal
contact force should exist between contacts. This contact force is
usually obtained by at least one of the contact members of a pair being
spring biased toward the other contact. Before insertion, the spring
biased contact takes up a free position from which it must be
displaced, or deflected, as the other terminal is inserted or
positioned. with a large number of contacts the force required to
displace or deflect the spring biased contacts becomes quite
substantial. Added to this is the frictional forces between contacts.
It has been proposed to mount connector parts on the
back plane which have provision for moving the contacts out of position
during insertion of the mating connector part, the contact being
released when the two connector parts are fully assembled. It is
necessary to provide the contact withdrawal facility at every possible
mounting position at the time of assembly of the enclosure structure
embodying the back plane as it is at least extremely difficult, if not
impossible, to add this facility at a later date. Such facility is
1 2 3 7 6
quote expensive and requires a high initial capital outlay, with every
board position having the contact withdrawal faculty.
Ivory, in the majority of situations, all board
mounting pistons are not used at Natalie installation of the
enclosure structure. It is a feature of the present invention that
substantially normal contact carrying connector parts are mounted on
the back plane and the contact withdrawal facility us provided on the
circuit boards. By this means the cost of the contact withdrawal
mechanism only occurs at the time a Crockett board is connected in to
I the back plane. Thus the capital outlay is spread over a period of
time, from initial installation until the time the final circuit board
is added.
The present invention provides a multiple contact
connector part, for attachment to an edge of a circuit board, the part
comprising an elongate housing, a plurality of cantilever spring
contacts mounted in the housing, in one or more linear arrays, an
elongate actuating member mounted for reciprocal longitudinal movement
in the housing and inter engaging formations on the housing and the
elongate actuating member which on reciprocal movement of the elongate
member, move it reciprocally on a direction normal to the longitudinal
movement to move the contacts out of a contact piston and return
the contacts to a contact piston.
The contacts can be on a single linear array or in, for
example, two parallel linear arrays with the elongate member acting on
both arrays.
The invention also provides a circuit board with a first
elongate housing, cantilever sprung contacts and elongate member on one
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,
edge or on opposite edges of the board. The invention further provides
a multiple contact connector comprising two connector parts, a first
connector part comprising an elongate housing, cantilever spring
contacts and elongate actuating member, and a second connector part
comprising a second elongate housing having contacts for engagement
with the cantilever spring contacts in the first elongate housing.
The invention will be readily understood by the
following description of certain embodiments, by way of example, in
conjunction with the accompanying drawings, in which:-
Figure 1 is a perspective view illustrating a "side
entry" form of connection, the circuit board having connector parts on
opposite edges;
Figure 2 is a perspective view of a more conventional front entry form of connection,
Figure 3 is a perspective view of a side entry mounting
embodying the present invention;
Figure 4 is a perspective view of a circuit board with
attached connector parts, as used in Figure 3;
Figure 5 is a very diagrammatic illustration of a
connector part attached to a circuit board, as can be used in Figure 4;
Figure 6 is a phantom illustration of various items of a
connector;
Figure 7 is a transverse cross-section through a
connector, on the line VII-VII of Figure 8;
Figure pa is a partial cross-section, similar to Figure
7, illustrating the deflected position of contact members; and
Figure 8 is a longitudinal cross-section on the line
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VIII-VIII of Figure 7.
Figures 1 and 2 illustrate two ways circuit boards may
be inserted. Figure 1 illustrates a "side entry" insertion, the
circuit board 10 inserted, and removed, by being moved sideways, a
connector part on opposite edges mating with another connector part on
a support structure or housing, indicated at 11. In Figure 2 is
illustrated the more conventional front entry where a connector part on
the edge of a circuit board is pushed straight in to another connector
part, with no relative lateral movement.
In Figure 2, as the board is pushed in, with a
conventional connector, the contacts on one of the boards must be
displaced or deflected sideways, simultaneously. This can result in
high forces to insert the board. In Figure 1, the contacts are
deflected one by one and so the insertion force builds up continuously.
However, a far bigger problem in this form of insertion is the
prevention of damage to contacts by the lateral movement of one set of
contacts relative to the other set. In fact, the contacts will be bent
and damaged if a circuit board was inserted in this manner, unless some
special provisions are made to prevent contact between the separate
sets of contacts before the circuit board is completely inserted.
Figure 3 is a perspective view of an arrangement in
which circuit boards are inserted in the "side entry" manner, using the
present invention. The circuit boards, indicated at 10 extend between
two support structures 11. Connector parts 12, having contact members
- not seen in Figure 3, are attached to the support structures 11.
Connector parts 14 having cantilever spring contacts - again not seen
in Figure 3 - are attached to opposite edges of the circuit boards 10.
..;
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Means are provided in the connector parts 14 for disengaging, or
deflecting, the cantilever sprung contacts prior to insertion of the
circuit boards by sliding connector parts 14 over connector parts 12.
These means are actuated by the levers 15, the levers in the up
position causing deflection of the contacts, while folding down of the
levers releases the contacts.
For a one side mounting, as in Figure 2, only one
connector part 12 is provided and only one connector part 14.
The arrangement of circuit board and connector parts 14,
as in Figure 3, is seen more clearly in Figure 4. The levers 15 are
pivotal mounted at 16 on the housing of the connector part 14. The
levers move actuators in a longitudinal direction, an actuator
indicated at 17. Cantilever spring contact members are displaced
outward into slots in the sides of the housing, indicated generally at
18.
Figure 5 illustrates diagrammatically one connector.
Connector part 12 is attached to a support structure, for example a
back plane 11. On the connector part 12 are mounted contact members
20. In the example, there are two rows of contact members 20.
Extending over the connector part is connector part 14 comprising an
elongate housing 21 within which is supported the elongate actuator or
actuating member 17. The actuating member 17 is capable of reciprocal
movement along the housing 21 and also capable of reciprocal movement
towards and away from the connector part 12. A lever 15 is attached to
one end of the actuator which is caused to move toward connector part
12 as it is moved sideways - longitudinally - by the lever 15. This is
obtained by inclined ramps or cams on the housing 21. Cantilever
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spring contacts 25 are postponed on the housing 21, in the example in
two lines, are on each side of the actuating member 17. The free ends
of contacts 25 make contact with the contact members 20.
Figure 6 illustrates the various individual items in
somewhat idealized form to illustrate the method of working. The
example illustrated is relatively short, for a connector with for
example, 100 contacts in two lines of 50. The connector illustrated in
Figure 4 for example, might be for about 200 contacts in two rows of
100. These figures are purely illustrative. In Figure 6 is seen, on
phantom, the elongate housing 21 of the connector part 14, and the
elongate actuating member 17. The elongate housing comprising
connector part 12 is also seen.
Housing 21 is in the form of a hollow box, open at the
bottom. From the top surface of the housing extends a number of
actuating member guide and cam members 26. The cam members 26 have
inclined cam surfaces 27. At each end of the housing depends a
deflectable locking member 28, each having a laterally extending cam
member 29. The actuating member 17 has apertures 30 there through and
the actuating member is positioned in the housing 21 with the guide and
cam members 26 and locking members 28 extending down through the
apertures 30.
In the example illustrated, the connector part 12 is in
the form of a housing having a central longitudinally extending slot
35 formed in an upstanding rib 34. The lower ends 36 of the guide and
cam members 26 ride in this slot, the lower ends of members 26 being
reduced in thickness. The housing 21 and actuating member 17, forming
connector part 14 are assembled to part 12, in the example illustrated,
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by sliding the housing 21 lengthwise over the part 12, the lower ends
36 sliding in the slot 35.
Initially, with the lever 15 in the folded down or
released position, as in Figure 59 the actuating member 17 is
positioned up against the inner top surface of housing 21, resting
above the cam members 29. On movement of the lever 15 to its
operative position, as in Figure 4, the actuating member is moved
longitudinally and is caused to move down by the cam surfaces 27. As
this downward movement occurs, the actuating member pushes down on the
cam members 29 deflecting the lock members 28.
It will be seen in Figure 6 that at each end of the
housing forming the connector part 12, a projection 38 extends into the
slot 35. These projections have two functions. Firstly, the locking
members 28, in their unreflected positions, are positioned in the slot
35 toward the front of the slot as considered in Figure 6. Thus the
locking members cannot pass out of the slot 35, or, if the housing 21
is separated from connector part 12, cannot enter the slot 35. On
movement of the actuating member to push down the actuating member on
guide and cam members 26, the locking members are deflected and can
then pass through the reduced width portions 39 of the slot. This
enables the housing 21, that is the connector part 14, to be assembled
to, or disassembled from, part 12.
The second function of the projection 38 is to ensure
the correct orientation of a circuit board on insertion - referred to
as polarity. At each end of the housing 21, the lower edges of the end
walls are shaped to pass over the housing forming connector part 12.
There is a central leg 40 which can pass into the slot 35. These legs
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have a projection 41 on one side. It will be seen that, as illustrated
in Figure 6, the projections 41 can pass below projections 38 and the
legs 40 can pass through the reduced width portions 39 of slot 35.
However if a circuit board and its attached connector part 14 is
reversed, that is the projections 41 extend in the other direction,
assembly of connector part 14 to connector part 12 cannot occur.
The first function of preventing assembly of the
connector parts unless the actuating member is in its downward
position, will be appreciated from Figure 7. Figure 7 illustrates the
connector in a connecting condition, that is the cantilever spring
contacts 25 are in electrical contact with contacts 20. The actuating
member 17 is in its upward position, resting on and being held
centrally and upward by the cam members 29 (Figure 6). As seen in
Figure 7, the bottom corners of the actuating member 17 are chamfered,
at 42. In the non-actuating position, as in Figure 7, the actuating
member is just touching, or preferably, slightly clear of the
cantilever spring contacts 25. The cantilever spring contacts have an
inwardly inclined section 43. Thus the spring contacts 25 press on
the contacts 20. It will be appreciated that any attempt, deliberately
or accidentally, to slide one connector part lengthwise relative to the
other will cause considerable damage to the contacts. Hence the
function of the projections 38 to prevent such movement unless the
actuating member is pushed down. The actuating member pushes on the
inclined section 43. This pushes the cantilever spring contacts
outward into the slots 18 in the side walls of the housing 21, as
indicated in dotted outline at aye.
The action of the actuating member 17 is illustrated
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also in Figure pa. In this figure, the actuating member is in the
downward positron and the chamfered corners 42 have pushed the
cantilever spring contacts 25 outward. A secondary effect which can be
provided also is illustrated on Figure pa. The contacts 20 can be
arranged so that in a free position they extend away from the connector
part 12, as shown. The upper ends of the contacts 20 rest in small
apertures in a rib 44 extending along the outer top edge of the
connector part 12. The apertures restrict outward movement of the
upper ends of the contacts 20. With this arrangement, as the actuating
member 17 moves upward and releases the cantilever spring contacts 25,
the spring contacts 25 press against the contacts 20 pushing them
against the connector part 12. The contacts 20 pivot about a position
close to their attachment to the bottom of the connector part 12 and a
wiping action occurs between the cantilever sprung contacts 25 and
contacts 20.
Figure 8 is a longitudinal cross-sect;on of a connector
as on Figure 7. This connector is a longer one than that illustrated
on Figure 6, and may have up to about 200 contacts on each connector
part. There would normally be three guide and cam members 26. The
pivotal attachment of the lever 15 to the actuating member 17 is
indicated at 45. A slot is required on ether the lever or the
actuating member to allow for the differential movement of lever and
actuating member.
While, in Figure 7, and in Figures 5 and 6, the
actuating member has been shown and described as moving towards
connector part 12 as the lever moves from an inoperative position, with
the pressing of the cantilever spring contacts 25 outwards, a different
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arrangement can be provided. Thus it can be arranged that the upward
movement of the actuating member, away from connector part 12, will
move the contacts 25 apart.
A front entry connector can have the polarity and
locking arrangement as in Figure 6, but this would require a small
sliding movement, longitudinal of the connector to obtain a correct
final assembly. Alternatively a connector without polarization and
locking features can be used and this will be very similar to the
arrangement illustrated in Figure 5.
