Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
1999-11-10
2001-10-23
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
06305949
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a press-fit pin, connector and printed circuit board-connected structure.
2. Description of the Related Art
The back sides of large-scale electronic equipment such as calculators and telephone exchanges have come to be connected to the electronic equipment main unit by a plurality of external cables. As the capabilities of these electronic instruments have increased so, too, has the number of external cables, to the extent that a single back wired board is insufficient and has come to be replaced with a two-piece back wired board assembly.
Specifically, that two-piece back side structure typically consists of a main back wired board electrically connected to the main unit and a sub back wired board fixedly mounted opposite to and a short distance away from the main back wired board. The sub back wired board is electrically connected to the main back wired board, with the external cables connected to the sub back wired board.
The structure that electrically connects the sub back wired board to the main back wired board bears examination. It should be noted at the outset that the density of the required electrical connections makes press-fit pins preferable to wires.
FIGS. 1A
,
1
B and
1
C depict a conventional press-fit pin
1
as well as the state in which it appears when pressed into position in the sub- and main back wired boards. The press-fit pin
1
is suitable for use with a printed circuit board assembly
4
composed of a first printed circuit board
2
and a second printed circuit board
3
disposed opposite each other and separated by a predetermined distance. The press-fit pin
1
has two press-fit sections, an upper first section
1
a
and a lower second section
1
b
. When pressed with a force F, the press-fit pin
1
passes through the stages shown in
FIGS. 1A and 1B
to arrive at the state shown in
FIG. 1C
, with the first press-fit section
1
a
inserted in the through-hole
2
a
of the first printed circuit board
2
and the second press-fit section
1
b
inserted in the through-hole
3
a
of the second printed circuit board
3
.
That is, the first and second press-fit sections
1
a
and
1
b
of the press-fit pin
1
are formed so as to fit the printed circuit board assembly
4
, so that, when the press-fit pin
1
has been pressed into place and assumes the state shown in
FIG. 1C
, the first press-fit section
1
a
is positioned inside the through-hole
2
a
of the first printed circuit board
2
and the second press-fit section
1
b
is positioned inside the through-hole
3
a
of the second printed circuit board
3
. In other words, a distance A between the center
1
ac
of the first press-fit section
1
a
and the center
1
bc
of the second press-fit section
1
b
is set so as to be equivalent to a distance B between the center of the first printed circuit board
2
in the direction of the thickness of the first printed circuit board
2
and the center of the second printed circuit board
3
in the direction of the thickness of the second printed circuit board
3
.
At this point a discussion of the force required to press the press-fit pin
1
into place is necessary. It is useful to think of this required force as two separate forces, one force required to press the first press-fit section
1
a
into the first through-hole
2
a
and another force required to press the second press-fit section
1
b
into the second through-hole
3
a
. As shown in
FIG. 2
, the force required to press the first press-fit section la into the first through-hole
2
a
changes as shown by line I. Similarly, the force required to press the second press-fit section
1
b
into the second through-hole
3
a
also changes as shown by line II in FIG.
2
. The total force required to press the press-fit pin
1
into place during the course of the pressing process is shown by line III, and is the sum of the force represented by line I and the force represented by line II.
As can be observed from
FIG. 2
, the insertion of the first press-fit section
1
a
into the through-hole
2
a
of the first printed circuit board
2
and the insertion of the second press-fit section
1
b
into the through-hole
3
a
of the second printed circuit board
3
takes place at the same time, so the peak
5
of the force represented by line I and the peak
6
of the force represented by line II appear at substantially the same time as well. Accordingly, the total force required to press the press-fit pin
1
into place has a high peak
7
as shown in FIG.
2
. As a result, a large compressive force in the axial direction is exerted on the press-fit pin
1
when the press-fit pin
1
is pressed into position and there is thus a possibility that the press-fit pin
1
may be bent in the process. If the press-fit pin
1
is bent the bent press-fit pin
1
must be extracted and replaced with a new press-fit pin
1
, interrupting the process of pressing the press-fit pins
1
into place and decreasing the efficiency of the overall production operation.
SUMMARY OF THE INVENTION
Accordingly, it is the object of the present invention to provide an improved and useful press-fit pin, connector and printed circuit board-connected structure, in which the disadvantage described above is eliminated.
The above-described object of the present invention is achieved by a press-fit pin comprising:
a first press-fit section to be pressed into a first through-hole provided on a first printed circuit board; and
a second press-fit section located closer to a tip of the press-fit pin than the first press-fit section, the second press-fit section to be pressed into a second through-hole provided on a second printed circuit board separated from the first printed circuit board by a predetermined distance,
the first press-fit section and the second press-fit section disposed so that the first press-fit section enters a first through-hole of a first printed circuit board at a time different from a time at which the second press-fit section enters a second through-hole in a second printed circuit board.
Additionally, the above-described object of the present invention is also achieved by the press-fit pin as described above, wherein the first press-fit section and the second press-fit section are disposed so as to be separated by a distance J between a center of a central portion of maximum diameter of the first press-fit section and a center portion of maximum diameter of the second press-fit section, such that the distance J is shorter than a distance C separating a center of the first through-hole in a direction of a thickness of the first printed circuit board and a center of the second through-hole in a direction of a thickness of the second printed circuit board.
Additionally, the above-described object of the present invention is also achieved by the press-fit pin as described above, wherein the first press-fit section and the second press-fit section are disposed so that a first boundary between a central portion of maximum diameter and an adjacent tapered portion of the first press-fit section and a second boundary between a central portion of maximum diameter and an adjacent tapered portion of the second press-fit section are separated by the distance J, such that the distance J is shorter than the distance C separating the center of the first through-hole in the direction of the thickness of the first printed circuit board and the center of the second through-hole in the direction of the thickness of the second printed circuit board.
According to the press-fit pin of the present invention, the points in time at which the pressing forces required to press the first and second press-fit sections into position peak are staggered and do not coincide, and therefore the total amount of pressing force required to press the press-fit pin into position is reduced compared to the conventional press-fit pin. As a result, the danger that the press-fit pin might bend during insertion can be reduced or eliminated.
Additionally, the above-d
Miyazawa Hideo
Okada Akira
Okuyama Takeshi
Sakurai Atsushi
Shimizu Manabu
Fujitsu Takamisawa Component Limited
Le Thanh-Tam
Sircus Brian
Staas & Halsey , LLP
LandOfFree
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