Metal fusion bonding – Process – With shaping
Reexamination Certificate
2001-07-19
2003-02-04
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
With shaping
C228S173400, C428S544000, C428S596000, C029S897200
Reexamination Certificate
active
06513700
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a welded structure for a boss and a bracket to be mounted in a cylindrical structure made of a sheet metal, and a welding method therefor.
2. Related Art
FIG. 9
is a sectional view showing one example of a cylindrical body having a boss in its inside and made of a sheet metal. In a cylindrical body
50
having a rectangular section and constructed of vertically opposed upper and lower sheets
51
and
51
and horizontally opposed side sheets
52
and
52
, there are arranged a boss for a mounting pin having a seat
54
, and a boss
55
having a seat
56
. These seats
54
and
56
are individually deposited on the right and left side sheets
52
and
52
from the inner side of the cylindrical body
50
. In the bosses
53
and
55
, there are formed pin mounting holes
57
which extend therethrough in the axial directions. Holes are also formed coaxially with the holes
57
and
57
through the side sheets
52
and
52
. In this structure, for example, the cylinder rod head
61
of a hydraulic cylinder to be mounted in the cylindrical body
50
is mounted by sandwiching it between the bosses
53
and
55
and by inserting amounting pin
60
, as indicated by double-dotted lines in
FIG. 9
, into the holes
57
and
57
and the mounting hole of the rod head
61
.
The cylindrical body
50
is manufactured by depositing the boss
53
and the seat
54
, the boss
55
and the seat
56
at first, then the seats
54
and
56
on the right and left side plates
52
and
52
, and then the side plates
52
and
52
and the upper and lower sheets
51
and
51
, to construct the rectangular cylindrical body
50
.
When the welded structure having the construction described above is manufactured, however, the bosses
53
and
55
and the seats
54
and
56
are deposited in advance on the side sheets
52
and
52
, and then the side sheets
52
and
52
and the upper and lower sheets
51
and
51
are deposited at the four corners to construct the rectangular cylindrical body
50
. This construction raises a problem that the manufacture has many steps and a long welding line and takes a long time and a high cost. Another problem is that the cylindrical body
50
has an increased total weight. Moreover, the numerous sheets are deposited to construct the cylindrical body so that the deposited portions have to be strengthened for enhancing the rigidity of the structure, but this high rigidity is hard to attain.
In recent years, with a view to solving these problems, it has been proposed for the arm of a working implement of a construction machine to form a compact cylindrical body by bending a sheet metal so as to raise the rigidity, to lessen the weight, to improve the field of view and to lower the cost. In this case, various shapes including circular and triangular shapes can be conceived as the sectional shape, which is exemplified by one of a generally triangular cylindrical body
71
, as shown in FIG.
10
. This cylindrical body
71
is manufactured by a process including the steps of: bending a sheet material
70
upward at first in the vicinity of its two end portions, as indicated by double-dotted lines; next bending the right and left portions upward, as indicated by arrows, on the apex of the triangle into the shape shown by solid lines; and finally depositing the central portion P of the base of the triangle, as located at an upper portion.
In the manufacture case having the aforementioned steps, when the bosses
53
and
55
or the bracket for the mounting pins is deposited in the prepared cylindrical body
71
, the outer peripheral portions of the bosses
53
and
55
and the bracket have to be deposited, according to the process of the prior art, on the cylindrical body
71
from the inner side of the cylindrical body
71
. In the manual welding case, therefore, the worker is required to perform the welding work by inserting the welding torch into the small-sized cylindrical body
71
while substantially failing to observe the welding line, so that sufficient welding strength and precision cannot be retained. Even with an automatic welding apparatus such as a welding robot, alternatively, it is extremely difficult to move the robot arm or the welding torch in the narrow space of the cylindrical body and to automate the welding work. On the other hand, it is also conceivable to form the cylindrical body
71
, after the boss
53
for the mounting pin and the bracket were deposited in advance on a sheet metal, by bending the sheet metal. According to this method, however, there is a problem that the sheet metal cannot be precisely bent because it is blocked by the deposited boss or the like. This problem makes it seriously difficult to practice that method.
From the discussion thus far made, it is an important target to achieve a welding method capable of depositing the boss or the bracket highly precisely and firmly in the cylindrical body formed in advance of the sheet metal.
SUMMARY OF THE INVENTION
Noting the problems thus far described, therefore, the present invention has an object to provide not only such a welded structure for a boss and a bracket in a cylindrical body as can have a light weight, retain a rigidity, an excellent durability and an easy manufacture but also a welding method therefor.
In order to achieve the above-specified object, according to a first invention, in a sheet metal structure including at least one of a boss and a bracket for mounting a member is mounted in a cylindrical body, a welded structure for a boss and a bracket is constructed: by boring holes of predetermined shapes in predetermined portions on the side face of a cylindrical body made of a sheet metal; by inserting seats of at least one of a boss and a bracket from the inner side into said holes; by mounting the member mounting portions of said boss and said bracket in said cylindrical body; and by welding the individual seats of said boss and said bracket on the side face of said cylindrical body from the outer side of said cylindrical body.
According to the first invention, the bores are formed in the side face of the prepared cylindrical body of the sheet metal, and the boss or the bracket and the side face of the cylindrical body are deposited from the outer sides of the holes. Even where the cylindrical body is made compact to fail to retain a space therein for the welding torch or the like to move, the boss or the bracket can be easily and reliably mounted and welded in the cylindrical body. This makes it possible to increase the degree of freedom for designing the sectional shape of the cylindrical body, to provide a light and highly rigid cylindrical body easily, to simplify the structure and to lower the cost.
According to a second invention, there is provided a welding process for a boss and a bracket of a sheet metal structure including at least one of a boss and a bracket for mounting a member is mounted in. a cylindrical body. The welding process comprises:
a) forming a cylindrical body of a thin sheet metal;
b) boring holes of predetermined shapes in predetermined portions on the side face of said cylindrical body;
c) inserting seats of at least one of a boss and a bracket from the inner side into said holes, and mounting the member mounting portions of said boss and said bracket in said cylindrical body; and
d) welding the individual seats of said boss and said bracket on the side face of said cylindrical body from the outer side of said cylindrical body.
According to the second invention, the pin mounting portion for the boss or the bracket, as prepared separately in advance, can be mounted in the cylindrical body prepared in advance, and the boss or the bracket can be deposited easily, highly accurately and reliably on the side face of the cylindrical body thereby to improve the welding workability of the boss or the bracket.
According to a third invention, in a working implement for a construction machine including at least one of a boss and a bracket for mounting a drive unit of an ar
Kawashima Kyuichi
Matsuda Yukinobu
Dunn Tom
Komatsu Ltd.
Stoner Kiley
Varndell & Varndell PLLC
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