Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
1999-08-04
2001-04-24
Sircus, Brian (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
Reexamination Certificate
active
06220871
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an electrical connector including a first connector having a plurality of electric contacts and a second connector having a plurality of electric contact elements adapted to electrically contact the electric contacts of the first connector when first and second connectors are connected, and more particularly to a contact construction of an electrical connector for electrically connecting electric contacts and electric contact elements of first and second connectors of the electrical connector.
One of hitherto used electrical connectors as shown in
FIG. 26
includes a first connector plate
10
and a second connector plate
20
which are brought into a detachable abutment against each other to electrically connect a plurality of electric contacts
11
made of hemispherical protrusions of solder or the like provided on one surface of the first connector plate
10
to a plurality of electric contact elements
21
provided on one surface of the second connector plate
20
. Such an electrical connector has a plug and socket mechanism (not shown) for detachably connecting the first and second connector plates
10
and
20
.
The first connector plate
10
is made of a ceramic or hard resin board having a rigidity and the second connector plate
20
is also made of a hard resin plate having a rigidity. The electric contact element
21
is a pin having a flange
22
and telescopically received in a contact element cylinder
30
made of a metallic material such that the pin is urged toward the electric contact
11
by an elastic member
31
such as a coil spring located in the cylinder
30
. With such an electrical connector, in general, the electric contacts
11
abut against or slidably contact electric contact elements to be electrically connected to each other.
Such an electrical connector has the following disadvantages.
(1) The construction for supporting the electric contact elements
21
is complicated to increase its manufacturing cost.
(2) Owing to the construction for supporting the electric contact elements
21
, the second connector plate
20
requires substantial spaces on its both sides which make it difficult to compact the electrical connector. Moreover, the contact element cylinders
30
for receiving therein the electric contact elements also somewhat require spaces which make it difficult to arrange the electric contact elements in high density.
(3) In order to avoid the disadvantage described in (2), it may be devised to provide metal foils as electric contact elements
41
on one surface of the board
40
as shown in FIG.
27
. In the case providing such metal foils on the board
40
, there is a risk of the electric contacts
11
and electric contact elements
41
incorrectly contacting each other due to the difference in height between the electric contacts
11
of the first connector plate
10
.
(4) Furthermore, even if an impedance value, for example, of the order of 50&OHgr; is desired between the electric contact elements
21
and grounding or earthing system (including a case having other grounding electric contact elements), the contact element cylinders
30
and the elastic members
31
would be constructionally longer with the construction shown in FIG.
26
. Moreover, it may be difficult to ensure the impedance of the order of 50&OHgr; with the dielectric constant &egr;
0
of the air and the relative dielectric constant &egr;
1
of a hard resin plate.
A plug and socket mechanism hitherto used is shown in
FIGS. 28A and 28B
to FIG.
31
. As shown in
FIG. 29
, a first connector
310
and a second connector
320
are detachably connected by the plug and socket mechanism. The second connector
320
is embraced between a housing
372
and a block
374
, and a flexible printed card board
324
extends from the housing
372
and the block
374
to be connected to pads
342
of a board
340
.
With this electrical connector hitherto used, bolts
338
pass through the housing
372
, the flexible printed card board
324
, the block
374
and the board
340
having apertures
384
and are tightened by nuts
382
screwed onto the ends of the bolts
338
, whereby these members are clamped as shown in FIG.
30
A. As surface mounting components are mounted on the board
340
on the side of the nuts
382
and the apertures
384
of the board
340
are must be formed so as to avoid the area of the board
340
used for the wiring, there is a tendency for the board
340
to become large. To eliminate this problem, the bit-insert
376
has been devised which is able to be clamped by screw means, while permitting a connector to be mounted by the surface mounting method as shown in FIG.
30
B.
The housing
372
is fixed by the bolts
338
to the block
74
having the bit-inserts
376
press-fitted therein. As shown in
FIG. 28B
, by fixing the metal layers
331
of the flexible printed card board
324
of the second connector
320
to the pads
342
of the board
340
, the block
374
to which the second connector
320
and the housing
372
are fixed is mounted on the board
340
. When the metal layers
331
are attached to the flexible printed card board
324
of the second connector
320
by soldering, the metal layers
331
are urged to the pads
342
of the board
340
as shown in
FIG. 28B
by means of a jig (not shown).
With this construction, the first connector
310
is inserted into a fitting opening
336
formed in the housing
372
to the second connector
320
secured to the board
340
and the block
374
to cause the electric contacts
312
of the first connector
310
to contact the electric contact elements
322
of the second connector
320
. During such an operation, the first connector
310
is held being urged to the second connector
320
as by urging jig (not shown). Such a construction is referred to herein as “plug and socket mechanism”.
The electrical connector having such a plug and socket mechanism suffers the following disadvantages.
(1) The electrical connector of this type has no means for securely urging the metal layers
331
of the flexible printed card board
324
to the pads
342
of the board
340
. Moreover, the flexible printed card board
324
is inferior in followability, causing incorrect contact between the electric contacts and electric contact elements.
(2) When the metal layers
331
of the flexible printed card board
324
are urged to the pads
342
of the board
340
, the metal layers
331
could not accommodate the difference in height between the pads
342
. Further, there is no means for ascertaining whether the soldered surfaces are correct so that there is a risk of the adjacent leads being bridged by solder.
(3) When the bit-insert
376
of the prior art is connected to the board
340
by soldering, there is a tendency for the air
378
to enter the soldered surfaces as shown in
FIG. 31
, causing defects or irregularities of soldered surfaces. As a result, the strength of the soldered portions becomes lower to cause defective connection of the metal layers
331
to the flexible printed card board
324
.
(4) Once the metal layers
331
of the flexible printed card board
324
has been connected to the pads
342
of the board
340
by soldering, the board
340
itself must be replaced to increase the running cost when the electric contact elements
322
of the second connector
320
have been worn off by repeated connections to and disconnections from the first connector
310
.
On the other hand, if there are any contaminations or foreign substances
435
(
FIG. 33A
) on the electric contacts and electric contact elements, when they are caused to abut against each other, good connections therebetween could not be obtained. In order to overcome this problem, the sliding contact between the electric contacts and electric contact elements has generally been employed so that the contaminations or foreign substances on the contacting surfaces are wiped or removed by the relative movement between the electric contacts and electric contact elements.
FIG. 32
illustrates part
Otsuki Tomonari
Yamazaki Yasue
Baker & Botts L.L.P.
DDK Ltd.
Dinh Phuong K T
Sircus Brian
LandOfFree
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