Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
1998-05-07
2001-08-07
Paladini, Albert W. (Department: 2841)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S261000, C174S267000, C029S739000, C257S697000, C361S760000
Reexamination Certificate
active
06271480
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electronic device and to a mounting structure thereof, and in particular relates to surface mounting electronic device and to a surface mounting structure for mounting the electronic device on at least one surface of a printed circuit board.
This application is based on Japanese Patent Application No. Hei
9-119940
, the contents of which are incorporated herein by reference.
BACKGROUND ART
The Japanese Patent Application, first publication, No. Sho
61-208247
discloses an electronic apparatus having a conventional mounting structure. The electronic apparatus comprises a flat-pack IC and a printed circuit board. The flat-pack IC has a plurality of terminal leads protruding horizontally from a body of the flat-pack IC, and alignment leads formed by bending several terminal leads at right angles. The printed circuit board has a plurality of terminal pads for establishing an electrical connection and alignment holes for receiving the alignment leads. The terminal pads are made on the upper surface of the printed circuit board, corresponding to the terminal leads of the flat-pack IC, and the alignment holes corresponds to the alignment leads of flat-pack IC. In the mounting structure of the electronic apparatus, by inserting the alignment leads of the flat-pack IC into the alignment holes on the printed circuit board, the terminal leads are properly aligned with the corresponding terminal pads.
When surface mounting electronic devices are mounted on both surfaces of the printed circuit board, a first electronic device is soldered on one surface, and a second electronic device is thereafter soldered on the underside. In the process of soldering the second electronic device, the board is turned over so that the first electronic device is positioned on the underside of the board.
However, when a heat radiating device is disposed on the upper side, corresponding to the first electronic device on the underside, the first electronic device may accidentally fall from the board, because the solder bonding the first electronic device melts due to the heat to solder the second electronic device and cannot support the weight of the first electronic device. In addition, the same problem occurs when the second electronic device is replaced, because the board is heated in order to remove the second electronic device.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an electronic device which can be prevented from accidentally falling off from one surface of a mounting board when another electronic device is soldered on the other surfaces of the mounting board.
Another object of the present invention is to provide an electronic device which can be prevented from accidentally falling off from one surface of a mounting board when another electronic device on the other surface of the board is replaced.
In order to accomplish the above object, an electronic device of the present invention comprises: a body having an underside; a plurality of conducting members for transferring electronic signals; and at least two alignment pins mounted perpendicularly on the underside, each of the alignment pins having flexible portion more easily bendable than the other portions. The flexible portion may be thinner than other portions of the alignment pins, or may be formed of a flexible material.
According to the present invention, it is possible to prevent the electronic device from falling off from the board when the electronic device positioned on the underside of the board is heated, because the projecting end of the alignment pin throughout the board can be easily bent.
In another aspect of the present invention, the alignment pins may be arranged at diagonal corners of the rectangular body, may be arranged at midpoints of two opposite sides of the rectangular body, or may be arranged at four corners of the rectangular body. The electronic device may be a pin-grid array for surface mounting.
In another aspect of the present invention, an electronic apparatus of the present invention comprises: a printed circuit board having a plurality of electrically conductive pads and a through hole; and an electronic device mounted on the board, the electronic device having an alignment pin and a plurality of conducting members for transferring electronic signals, the conducting members being connected to the pads, wherein the alignment pins are inserted into the through holes, the projections of the alignment pins from the through holes being bent in order to establish and to maintain a predetermined position of the electronic device relative to the board. A plurality of the electronic devices may be mounted on both surfaces of the board.
It is also possible to prevent the electronic device on one surface of the board from falling off from the board when another electronic device is subsequently mounted on the other surface of the board, because the alignment pins of the electronic devices are inserted into the through holes and the projecting ends of the alignment pins are bent.
REFERENCES:
patent: 5296652 (1994-03-01), Miller, Jr.
patent: 61-76970 (1986-05-01), None
patent: 62-243347 (1987-10-01), None
patent: 63-290000 (1988-11-01), None
patent: 64-23561 (1989-01-01), None
patent: 2-135766 (1990-05-01), None
patent: 4-239166 (1992-08-01), None
patent: 5-206360 (1993-08-01), None
Ikeda Hironobu
Yamaguti Yukio
McGinn & Gibb PLLC
NEC Corporation
Paladini Albert W.
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