Mining or in situ disintegration of hard material – Cutter tooth or tooth head
Reexamination Certificate
1999-04-22
2002-05-14
Bagnell, David (Department: 3673)
Mining or in situ disintegration of hard material
Cutter tooth or tooth head
C299S039800, C299S102000, C228S214000, C228S164000, C403S381000
Reexamination Certificate
active
06386641
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a design to promote welding in corner regions and more particular to the use of a fin extending outwardly from an outside corner region to promote the proper formation of a weld around such a corner region.
2. Description of the Related Art
Welding is defined as the process of uniting two members by heating them until they are molten and fused, with or without the use of a filler material.
The focus of this application will be directed to welding utilizing a filler material to join two parts which intersect at a corner and for which weld filler must be used to produce a continuous weld around the corner.
Manual welding typically is labor intense and requires a high level of skill on behalf of the welder to efficiently produce a strong high quality weld. Because there are frequently great demands for production placed upon a welder, there is always a desire to improve efficiency by either improving the manner in which the weld is laid or by providing a design which requires less weld material. A design which may permit both of these beneficial features is highly desirable.
Welding material around the corner of a workpiece presents unique problems to which the subject invention is directed. As an example,
FIG. 1
, which is prior art, illustrates a system by which a first member
10
is secured to a second member
15
by a weld
20
. The first member
10
has at least a first side
25
and a second side
30
. Each side has an upper portion
32
and a lower portion
34
wherein the lower portion
34
is chamfered relative to the upper portion
32
. The weld
20
is fused to the lower portion
34
of at least the first side
25
and the second side
30
of the first member
10
. The weld
20
is additionally fused to the surface
35
of the second member
15
thereby securing the first member
10
to the second member
15
.
Although defects associated with welding may occur along any portion of the weld
20
, the outside corner portions of welds seem to more frequently have defects. The first member
10
which is illustrated as a solid piece, has only outside corners
36
,
37
,
38
,
39
. To put this in perspective, if the first member
10
was hollowed out to form a cavity having a perimeter of the same shape as the exterior of the first member
10
, the enclosed corners would be referred to as inside corners.
FIG. 2
illustrates a section view of the corner portion of the weld along arrows “
2
—
2
” in FIG.
1
. The lower portion
34
of the side
25
is not illustrated in either this view or the view to be discussed with FIG.
3
. In
FIG. 2
, the bottom face
40
of the first member
10
contacts the surface
35
of the second member
15
. Weld
20
is used to attach the first member
10
to the second member
15
. The metal filler of the weld
20
penetrates the side
25
of the first member
10
and simultaneously penetrates the surface
35
of the second member
15
. However, it is not uncommon when welding a corner region to produce a defect known as a rollover, which is also called an overlap. Such a defect is associated with fillet welds and can be produced when either the current of an arc welding machine is too low to properly fuse the second member
15
or the travel speed for the welding process is too low to accept the amount of metal filler being deposited. As a result, a portion of the weld
20
merely flows onto an area of surface
35
and does not fuse with the surface
35
. The rollover portion, which is indicated by 50 must be removed to ensure the integrity of the weld
20
. Such a defect must be removed by grinding, which requires additional time and labor.
Another type of weld defect which is not uncommon in corner regions is illustrated in FIG.
3
and is referred to as an undercut.
FIG. 3
is a view similar to
FIG. 2
illustrating a different defect. An undercut is an irregular gouge which is generally found in the upper toe of a horizontal fillet weld. With reference to
FIG. 3
, the first member
10
has a bottom face
40
which contacts the surface
35
of the second member
15
. However, in this situation, the weld
20
droops from a recess or undercut
55
produced in the side
25
of the first member
10
. The side
25
of the first member
10
has been melted but has not been refilled with weld material. Most often this defect is caused by improper selected welding conditions such as the electrode angle, travel speed and welding current. It is more likely to occur when attempting to make fillet welds with legs that are more than 0.3 inches in length. Just as a with a rollover defect however, such defects are unacceptable if the integrity of the weld is to be maintained and such defects must be removed. These defects in welds on outside corners may be avoided but only at the cost of a significant increase in welding time and expense.
U.S. Pat. No. 3,832,523 discloses a method for electrical arc welding. In
FIG. 12
of that patent, a segment
50
is illustrated which is used on a vertical section for preventing a resulting weld bead which is not completely solidified from drooping. Segment
50
acts as a physical barrier to the weld material. As a result, the section on the plates under segment
50
will not be covered with weld material and therefore the weld will not be continuous. Furthermore, the weld does not extend around a corner and many applications require a continuous bead of weld material around a corner.
U.S. Pat. No. 4,208,563 illustrates a welding method using a break away flux dam in which copper wires are used to surround the weld area and create a pool of molten weld metal with a top layer of flux. While this illustrates a manner of containing a weld, it once again does not address a weld around a corner with a continuous bead of weld material.
A design is needed which permits a welder to secure a first member, which may be metal, having outside corners to a second member, which also may be metal, while applying a continuous weld around the corners of the member in an expedient fashion that will provide a weld with integrity and minimize the potential for producing defects such as rollover and undercut while also reducing the time and cost of welding.
While such a design is applicable to welding any two members with outside corners, it is of particular significance in securing a bit block or base to a rotatable member, such as a drum, wheel or chain, for equipment used in construction operations, such as road planning or trenching, or in mining operations, such as coal mining.
BRIEF SUMMARY OF THE INVENTION
One embodiment of the invention is directed to a first member for welding to a second member wherein the first member is comprised of a body having a top, a bottom and a face on the bottom for contacting a surface on the second member. The first member has a plurality of sides between the top and the bottom including a first side adjacent to the face, and a second side adjacent to the face. The first side and the second side converge to define an outside corner region between the top and the bottom. A fin extends from the corner region to promote the formation of a weld in the corner region.
A second embodiment of the invention is directed to a system which includes the first member just described mounted upon a second member using weld material.
A third embodiment of the invention is directed toward one application of the first member as a metal block for mounting upon a metal drum used in mining or construction operations.
A fourth embodiment of the invention is directed toward one application of a system including the first member as a metal block mounted to a metal drum and secured with weld material for use in mining or construction operations.
REFERENCES:
patent: 1382199 (1921-06-01), Lachman
patent: 2885462 (1959-05-01), Sylvester
patent: 3832523 (1974-08-01), Kitani et al.
patent: 4097716 (1978-06-01), Reichelt, Jr. et al.
patent: 4159746 (1979-07-01), Wrulich et al.
patent: 4208563 (1980-06-01), Frantzreb, Sr. et al.
patent: 4343516 (1
Bagnell David
Kennametal PC Inc.
Kreck John
Weldon Kevin P.
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