Electric heating – Metal heating – For bonding with pressure
Reexamination Certificate
2000-05-25
2003-10-21
Dunn, Tom (Department: 1725)
Electric heating
Metal heating
For bonding with pressure
C219S091210, C219S092000, C219S118000, C228S141100
Reexamination Certificate
active
06635843
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a strip connecting apparatus and method for connecting end portions of strips with each other by a seam welding method, and more particularly to a technology for overlapping end portions of strips one on another in which an insulation coating such as a scale coating, a plated layer or an insulative surface coating such as a surface coating layer is present on the surfaces of the strips for the seam welding.
2. Description of the Related Art
In order to weld in a stable manner the strips in which the insulative surface coating is present, it is necessary to remove the insulative surface coating. As a method for removing the insulative surface coating, there are known examples as follows.
(1) In the case where oxidized coating is present in welding material, it is removed by polishing the surface with a wire brush (see Japanese Patent Application Laid-Open No. Hei 5-104252 et al.)
(2) In the case where the laminate steel plate is welded, the resin coating on the surface of the steel plate is removed (see Japanese Patent Application Laid-Open No. Hei 5-177764).
(3) As a means for removing the applied coating of the coated steel plate, it is possible to use a thermal means with a high energy density beam such as a laser beam or an electron beam. For instance, it is possible to use a chemical means such as chemical agent or plasma or a mechanical means such as a grinder, a file or a sandblast or the like (Japanese Utility Model Application Laid-Open No. Hei 1-80277).
As apparent from these known examples, it is difficult to perform the welding method for the material in which the coating is present on the surface. It is a task how the coating is removed.
A flash welding method or an arc welding method such as MIG or TIG has been used for bonding the strips after the hot pressing process also in the steel process line, for example. (According to these welding methods, it is possible to perform the welding without any adverse affect on the insulative surface coating (see Japanese Patent Application Laid-Open No. Hei 3-52778).
However, these welding methods suffer from problems that, for example, the apparatus is expensive and the welding time is long. Therefore, in order to solve these problems, a welding method for a steel split has been proposed (Japanese Patent Application Laid-Open No. Hei 3-52778).
The Japanese Patent Application Laid-Open No. Hei 3-52778 discloses a method in which the respective leading steel strip (leading coil) and the trailing steel strip (trailing coil) which are overlapped one on another are depressed by a pressure down roller (swaging roll) and the insulation coating such as a scale coating or the like is removed by the working heat that occurs during this process.
However, according to this method, since the welding is completed under the condition that the scale of the weld bond portion is rolled in, it is impossible to ensure the welding quality in a stable manner.
Also, as a method for removing the surface coating on the strip, the method shown in
FIGS. 16 and 17
are known.
FIG. 16
shows a method in which, after strips
1
a
and
1
b
have been cut, upper and lower pairs of brushes
11
,
12
;
13
,
14
are brought into contact with upper and lower surfaces of the strips
1
a
and
1
b
, respectively, to thereby remove the surface coating. If the brushing is repeated, as shown in
FIG. 17
, there is a problem in that an outer circumferential portion of the disc-like brushes
11
to
14
is locally abraded and it is impossible to perform the surface coating process in a stable manner. Namely, as shown in
FIG. 17
on an enlarged scale, when the edges of the strips
1
a
and
1
b
are brushed, the brushes
11
to
14
are locally worn so that stepped portions are generated in the brushes
11
to
14
. As a result, in some cases, edge portions A of the upper brushes
11
and
12
and the lower brushes
13
and
14
which have not been abraded are brought into contact with each other so that the strip surfaces that are to be abraded are not abraded.
Furthermore,
FIG. 18
shows an example in which after the cut of the strips, the end portions of the two strips are brought into abutment against each other, and under this condition, the surface coating is to be removed by a pair of upper and lower disc-like brushes
41
and
42
. As shown in
FIG. 19
, in the case where there is difference in thickness of the two strips
1
a
and
1
b
to be bonded, there is a problem in that the surface coating on one strip
1
b
(thinner strip) could not be removed.
SUMMARY OF THE INVENTION
Accordingly, in order to overcome the above-noted difficulties inherent in the conventional cases, an object of the present invention is to provide a strip connecting apparatus and a method therefor which are less costly, short in welding time and high in welding quality.
In order to attain the above-described object, a strip connecting apparatus according to the present invention is provided with a surface coating removing device for removing insulative surface coating of end portions, to be welded, of a leading strip and a trailing strip before cutting the strips, a cutting device for cutting the end portions, to be welded, of the leading strip and the trailing strip and a welding device for overlapping the cut end portions of the leading strip and the trailing strip and seam welding the cut end portions with each other.
Also, according to one embodiment of the present invention, the cutting device for cutting the end portions, to be welded, of the leading strip and the trailing strip, respectively, is a rotary shear.
Furthermore, according to another embodiment of the present invention, the cutting device for cutting the end portions, to be welded, of the leading strip and the trailing strip, respectively, is a guillotine shear.
Furthermore, according to still another embodiment of the present invention, the surface coating removing device for removing the insulative surface coating of the end portions, to be welded, of the leading strip and the trailing strip comprises a first removing device for removing the insulative surface coating of the leading strip and a second removing device for removing the insulative surface coating of the trailing strip, and the first removing device and the second removing device are installed independently of each other.
Also, according to still another embodiment of the present invention, the surface coating removing device and the welding device are provided on a common carriage that may move on a common base.
Furthermore, according to still another embodiment of the present invention, the surface coating removing device for removing insulative surface coating of the end portions, to be welded, of the leading strip and the trailing strip is composed of a rotary tool having a polishing surface for coming into contact with the surfaces of the leading strip and the trailing strip, and for cutting, and the polishing surface of the rotary tool is automatically controlled to be kept at a constant position relative to the surfaces of the leading strip and the trailing strip.
Furthermore, according to still another embodiment of the present invention, a rotary shaft of the rotary tool is arranged in parallel with the surfaces of the leading strip and the trailing strip, and an outer circumferential portion of the rotary tool is brought into contact with the surface of the leading strip and the trailing strip.
Also, according to still another embodiment of the present invention, a rotary shaft of the rotary tool is arranged to be slanted relative to a line vertical to the surfaces of the leading strip and the trailing strip, and an outer circumferential portion of the rotary tool is brought into contact with the surface of the leading strip and the trailing strip.
Furthermore, according to still another embodiment of the present invention, the cutting device is provided so as to be movable on a common base independently of a carriage that is movable on the common b
Sodeno Keiji
Takeda Akimichi
Yoshida Masaru
Dunn Tom
Edmondson L.
Mitsubishi Denki & Kabushiki Kaisha
Sughrue & Mion, PLLC
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