Metal fusion bonding – Including means to move or guide applicator
Reexamination Certificate
2001-07-26
2002-10-29
Elve, N. Alexandra (Department: 1725)
Metal fusion bonding
Including means to move or guide applicator
C228S180100, C228S186000, C228S225000
Reexamination Certificate
active
06471109
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for soldering for a work conveyed to a predetermined working position by using soldering irons. Further, the present invention relates to a soldering land of a printed circuit board having a slit which is formed for inserting a metal plate.
2. Description of the Related Art
In a conventional soldering method, a soldering iron is disposed above a manufacturing line by which printed circuit boards are successively conveyed. On the printed circuit board, circuit components are mounted. The soldering iron descends toward the printed circuit board conveyed to a predetermined working position and soldering is automatically performed, supplying solder to a tip of the heated soldering iron. In this method, if oxidized solder gathers around the iron tip, soldering performance is greatly lowered. Therefore, an air blow is carried out to clean the iron tip once in five to twenty times of the soldering.
As to the above method, working of the soldering is interrupted while cleaning is carried out. Thus, operating efficiency of equipment is low. Further, upon carrying out the cleaning by the air blow, temperature of the iron tip lowers. Accordingly, there arises a problem in that poor soldering is frequently performed just after the cleaning of the iron tip. Moreover, when the cleaning is carried out once in a plurality of times of the soldering, the soldering is performed in a state that new solder is supplied to the iron tip with old solder thereon until the next cleaning step is carried out. Accordingly, it is difficult to keep the solder of the iron tip at a constant amount. In view of this, there is a fear that uniform soldering is not performed.
By the way, when a circuit board is manufactured, dip soldering is performed in the following manner. Metal pins of electronic parts are inserted into holes formed in the circuit board on which wiring is printed. A face of the printed circuit board, from which the metal pins project, is dipped in a tub containing the solder melted by a heater. Then the metal pins are soldered together.
On the other hand, for circuit components protruding from the printed circuit board, a metal plate is provided in order to increase strength of its attachment by enlarging a soldering area. This metal plate is inserted into a slit formed in the printed circuit board after the printed circuit board was dip-soldered. The slit has a soldering land formed all around the slit. After insertion of the metal plate, the metal plate is soldered.
However, as shown in
FIG. 5A
, if a soldering land
81
is formed all around a slit
80
, the slit
80
is sometimes closed by tension of solder
82
adhering to the soldering land
81
when the dip soldering is performed. The state that the slit
80
is closed with the solder is shown in FIG.
5
B.
Moreover, as shown in
FIG. 6A
, when a soldering land
91
is formed half around the slit
80
in order to prevent from closing the slit
80
, the slit
80
is not closed by the dip soldering. However, when a metal plate
93
is inserted into the slit
80
and soldered, the solder hardly goes round to the other side of the slit
80
where the soldering land does not exist. Thus, there arises a problem in that unsatisfactory soldering tends to be performed and sufficient strength is not obtained.
SUMMARY OF THE INVENTION
In view of the foregoing, it is a primary object of the present invention to provide a soldering method and apparatus in which operating efficiency of equipment is improved and good soldering is performed.
It is a second object of the present invention to provide a soldering method and apparatus in which uniform soldering is performed.
It is a third object of the present invention to provide a soldering land of a printed circuit board in which a slit formed in the printed circuit board is prevented from being closed when dip soldering is performed.
It is a fourth object of the present invention to provide a soldering land of a printed circuit board in which it is possible to perform good soldering for a metal plate inserted into a slit formed in the printed circuit board.
In order to achieve the above and other objects, the soldering method and apparatus according to the present invention comprises a plurality of soldering irons fixed to a sliding plate at a predetermined interval. Further, the soldering land according to the present invention comprises a main-land and a sub-land.
In a preferred embodiment, The soldering irons and the sliding plate are integrally moved by a plunger which is fixed to one end of the sliding plate. The soldering irons reciprocate by a predetermined distance in a rectangular direction relative to a conveyor belt. One of the soldering irons is moved to a working position where soldering is performed for a work put on the conveyor belt. At the same time, the other of the soldering irons is separated from the working position and moved to a cleaning position. While one of the soldering irons solders for the work, the other of them is cleaned at the cleaning position by a nozzle shooting air.
The soldering land according to the present invention is constituted of the main-land and the sub-land. The main-land is formed along only one of longer sides of the slit formed in the printed circuit board. The sub-land is elongated from the main-land along a shorter side of the slit. The soldering land is not formed all around the slit so that solder does not spread over the slit when dip soldering of the circuit board is performed. Accordingly, the slit is prevented from being covered with the solder. After the dip soldering, the metal plate is inserted into the slit and soldered. When the metal plate is soldered, the solder adheres to the metal plate along not only the main-land but also the sub-land. Thus, great strength for soldering the metal plate is obtained.
REFERENCES:
patent: 3887904 (1975-06-01), Krag
patent: 3917147 (1975-11-01), Vanyi
patent: 4678886 (1987-07-01), Kawaguchi
patent: 4805830 (1989-02-01), Kawaguchi
patent: 4851614 (1989-07-01), Duncan, Jr.
patent: 5525777 (1996-06-01), Kukuljan
patent: 2145646 (1985-04-01), None
patent: 2145646 (1985-04-01), None
Muramatsu Masayoshi
Watanabe Ken'ichi
Elve N. Alexandra
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
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