Note: Descriptions are shown in the official language in which they were submitted.
86~2
1o5~988
This invention relates to an electrlcal connector,
and particularly to an electrical connector for use ln
mounting a leadless intergrated circuit package on a printed
circuit board.
Many forms of such connectors are known, but kno~n
connectors suffer from the disadvantage that they do not
adequately meet the conflicting requirements of providing
a low assembl~ force thereby to avoid damaging of the
package, connector, or board, while providing a satisfactorily
high contact force between the package and the connector,
and between the connector and the board.
According to this invention there is provided an electrical
connector for use in mounting a leadless integrated circuit
package on a printed circuit board, comprising a body of
electrically insulating material carrylng two rows of
electrical terminals each providing a first contact point
for contacting a contact on an integrated circuit pac~age,
and a second contact point for contacting a conductor
~ on a printed circuit board, in which each terminal comprises
first and second integrally formed beam members joined by
a U-shaped bight, the first contact point being on the outer
surface of the first beam member, the second contact point
being on the outer surface of -the second beam member, and
the free end of the second beam member being secured to the
body of the connector.
An electrical connector according to this invention
will now be described by way of example with reference to
the drawing, in which:-
Figure 1 is a perspective view of the connector; and
Figure 2 is a cross-section through part of the
2.
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1051988
connector.
The connector to be described is for use in mounting a
leadless integrated circuit package 1 on a printed circuit
board 2, the package 1 having contacts 3 which are to be
connected to conductors 4 on the board 2 by the connector.
The connector comprises a body 5 moulded in one-piece
from electrically insulating material such as glass filled
phenylene oxide, and having end walls 6 and side walls 7
which together define an area to receive the package 1.
The upper (as seen in the drawing) inner edges of the side
walls 7 and bevelled as shown at 8 to guide a package 1 onto
the body 5 as required.
Beneath the package receiving area is a base 9 which
is stepped to provide a rectangular ledge 10 on which the
package 1 rests as shown in Figure 2.
The base 9 also contains two rows of through cavities
11, the rows extending parallel to the side walls 7.
Each cavity 11 contains an electrical terminal 12 formed
of metal such as berylium copper and which has a first
contact point 13 for contacting a contact 3 on the package 1,
and a second contact point 14 for contacting a conductor 4
on the printed circuit board 2. The terminal 12 comprises
first and second integrally formed beam members 15 and 16
joined by a U-shaped bight 17, the first contact point 13 being -
on the outer surface of the first beam member 15, and the
second contact point 14 being on the outer surface of the
second beam member 16.
A free end portion of the second beam member 16 is bent
lnto a substantially U-shape 18 with the arms of the U-shape 18
extending transversely of the remainder of the second beam
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1051988
me~ber 15, tne l~-shaped portion 18 being received in a recess
19 in a side wall 7 of the body 5 and being secured therein
by means of a lance 20 struck from the outer arm of the
U-shaped portion 18 and engaginy ln a hole 21 in the
side wall 7, ~hich hole 21 is accessible from the outside
of the connector for release of the lance 20 by means of
a suitable tool. Each terminal 12 is thus releasably
secured to the body 5 of the connector in the required
position.
The base of the recess 19 containing the U-shaped portion
18 of the second beam member 16 has a hole 22 therein
accessible to the outside of the connector for insertion of
a test probe to contact the terminal 12. The outer
surface of each side wall 7 is recessed to provide access
to the test probe holes 22.
~ free end portion 23 of the first beam member 15
is bent to extend away from the second beam member 16,
the bend providing a smooth rounded surface 24 for engagement
with the inner surface of the side wall 7 thereby to restrict
movement of the free end of the first beam member lS to
directions transverse of the second beam member 16.
The free end portion 23 of the first beam member 15 is
received when the connector is not in use, and as shown
in dashed line in Figure 2, in a recess 25 in the wall 7
` 25 thereby to restrain the free end portion 23 against movement
away from the second beam member 16 or towards the bight
17 of the terminal 12.
. As clearly shown in Figure 2, the first beam member
lS is bent twice to provide a step shape extending away from
the second beam member 16, the first contact point 13 being on
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105~988
the portion of the step adjacent the free end portion 23
of the first beam member.
As shown in Flqure 2, the second contact point 14 is
carried on an outwardly directed kink 26 in the second beam
member 16, whlch kink 26 passes about a bar 27 formed
integrally with the body 5 and extending the length thereof.
The bar 27 serves to limit deflection of the second beam member
16 towards the first beam member 15.
The contact points 13 and 14 may be simple dimples
formed in the beam members 15 and 16, or otherwise may be
deposits of conductive material, such as tin, on the beam
members 15 and 16 at the appropriate points.
The base 9 of the body 5 contains a central recess 28
having a hole 29 at the centre thereof and extending through
the base 9. For mounting the connector on the printed -
circuit board 2, the recess 28 receives a metal block 29 having
a screw-threaded hole therein in alignment with the hole
28 in the base 9, and a bolt 30 ~s passed through a hole in
the board 2, and through the hole 28 in the base 9 to engage
in the hole in the block 29 thereby to clamp the body 5
of the connector to the board 2 with the second contact points
14 of the terminals 12 of the connector in engagement with
conductors 4 on the board 2, as shown in Figure 2.
Each end wall 6 of the body 5 of the connector carries
an integrally formed upstanding boss 31 which in turn carries
a post 32 having an enlarged vertically split head 33.
Th,e pac~age 1 is located on the connector by passing
the heads 33 through holes in the package 1, the halves of
the heads 33 being resiliently urged together during this
action, until the package 1 comes to rest on the ledge 10
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105~98t3
of the body S of the connector (as shown in Figure 2), when
the heads 33 will have passed through the holes in the package
1 and will have opened out again to retain the package 1
on the body 5 of the connector, as shown in Figure 2, with
the first contact points 13 of the terminals 12 in contact
with contacts 3 on the package 1. The package 1 is then
clamped to the connector by means of a clamp (not shown).
As illustrated by Figure 2, the shape of the terminals
12 ~nd the manner in which they co-operate with the body S
of the connector provide a multidirectional wiping action
between the first contact points 13 of the terminals 12 and
the contacts 3 of the package 1.
As the package 1 is pressed down over the posts 31 the
terminals 12 are distorted from their non-loaded position
shown in dashed line in Figure 2, to their loaded position
shown in solid line in Figure 2. The first contact point
13 of each terminal 12 is moved both downwardly and
rotationally as can be seen from the change in angle to
20 ` the horizontal between the dashed line position and the
solid line position of the portion of the first beam member 15
carrying the first contact point 13, this resulting in the
wiping action between each first contact point 13 and the
associated contact 3 on the package 1.
.
6.
