Electric heating – Metal heating – For bonding with pressure
Reexamination Certificate
2000-03-28
2001-11-27
Dunn, Tom (Department: 1725)
Electric heating
Metal heating
For bonding with pressure
C219S084000
Reexamination Certificate
active
06323453
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a resistance seam welder of the type employing opposed weld wheels functioning as electrodes for permitting creation of a seam weld between overlapping parts of a workpiece which is fed into the nip between and engaged by the weld wheels and, more particularly, to an improved bearing support arrangement for one of the weld wheels to permit minimization of inertia and hence increased movement flexibility of the weld wheel so as to more rapidly respond to variations in thickness of the material being welded as it is fed through the nip, and to simultaneously permit compensation for the significant reduction in diameter of the weld wheel caused by wear as a result of ongoing operation of the seam welder.
BACKGROUND OF THE INVENTION
In a conventional seam welder of the resistance type, the welder is conventionally provided with upper and lower weld rolls which function as electrodes and which are relatively urged toward one another so as to permit material to be welded, such as overlapping sheets, to be relatively fed into and through the nip between the opposed weld wheels. The weld wheels directly engage the overlapping sheets and effect compression and electric heating so as to effect both welding and mashing of the overlapping sheets to create what is known as a seam weld.
Referencing
FIG. 1
, there is illustrated a conventional seam welder
10
wherein there is respectively provided upper and lower weld wheels
11
and
12
respectively supported for rotation about axes
13
and
14
, these latter axes extending approximately parallel. The upper and lower weld wheels have their opposed peripheries substantially contacting at the nip
15
, and material to be welded is fed into and through this nip. The material to be welded typically employs a pair of sheet metal parts or portions such as illustrated at
16
and
17
in
FIG. 2
, which portions have an overlapping area or region
18
which is relatively longitudinally fed into the nip so as to permit creation of a seam weld between the overlapping portions. The actual creation of the seam weld and the technology associated with doing so is well known, so that further detailed description of the actual welding steps will not be described in detail.
In the conventional seam welder
10
, the upper weld wheel
11
is nonrotatably secured to a rotatable shaft
21
which in turn is rotatably supported within an electrically conductive bearing assembly
22
, the latter having a nonrotatable outer housing
23
which has an electrically conductive mounting plate
24
fixed thereto. This conductive mounting plate
24
in turn mounts thereon an electrical insulator
25
which in turn cooperates with a lower end of a vertically reciprocal ram
26
, the latter being slidably guided within the stationary machine frame
27
. The upper end of ram
26
is acted on by a conventional air pressure cylinder
28
which is appropriately energized by pressurized air so as to impose a downward force on the ram which in turn is transmitted downwardly so as to be imposed on the upper weld wheel
11
and thus on the work located in the nip
15
.
The lower weld wheel
12
is also nonrotatably supported on a shaft
31
which is also rotatably supported within an electrically conductive bearing assembly
32
, the nonrotatable housing
33
of which also fixedly joins to an electrically conductive plate
34
, the latter being stationarily supported on a stationary part
36
of the machine frame through an intermediate electrical insulator
35
.
The electrically conductive members or plates
24
and
34
are in turn joined to and supplied with electrical energy from a conventional welding transformer
37
by being respectively connected thereto through flexible conductive straps
38
and
39
.
A conventional and known construction of the electrically conductive bearing assembly
22
or
32
is illustrated in
FIGS. 6-7
. This bearing assembly
22
includes the outer housing
23
which is disposed generally in surrounding relationship to the shaft
21
, and this bearing assembly provides seal structure, bearing structure and electrically conductive structure cooperating between the housing
23
and the shaft
21
. For example, opposite ends of the elongate housing
23
are normally provided with annular seals
41
to create a sealed relationship between the shaft and the housing bearings
42
such as roller or ball bearings are also typically provided for cooperation between the housing
23
and the shaft
21
, which bearings
42
are disposed adjacent opposite axial ends of the housing
23
and are typically positioned axially inwardly from the respectively adjacent seals
41
. The housing
23
in addition defines therein an annular chamber
43
of substantial size, which chamber extends axially between the bearings
42
in surrounding relationship to the shaft
21
. This chamber
43
contains therein at least one and typically several electrically conductive contact assemblies
44
positioned in axially adjacent relationship for transmitting electrical current from the housing
23
to the rotating shaft
21
. In the illustrated arrangement, this contact assembly
44
includes a pair of contact shoes
45
which are disposed in straddling relationship on generally opposite sides of the shaft
21
, with these opposed contact shoes
45
typically being constructed of copper and having opposed recesses which are provided with a silver layer
46
thereon, these silver layers
46
in turn being disposed in slidable current-conducting contact with the exterior of the rotatable shaft
21
. The contact members
45
themselves are normally urged inwardly into proper contacting engagement with the shaft
21
by appropriate wedges
47
which coat between the contact members and the housing
23
, with these wedges
47
typically being acted on by springs
48
. The chamber
43
is typically provided with oil, such as castor oil, circulated therethrough for cooling and lubricating purposes.
In the conventional seam welding apparatus as illustrated by
FIG. 1
, the electrically conductive bearing assemblies such as illustrated at
22
and
32
are typically mounted directly at or axially adjacent the weld wheel or electrode, with the latter being positioned substantially directly adjacent at least one axial end of the bearing assembly, with the upper bearing assembly
22
then being acted on directly by the pressure ram
26
so that the pressing force which acts downwardly through the ram onto the upper weld wheel and thence through the workpiece onto the lower weld wheel is accordingly positioned in close proximity to the work plane, namely the vertical plane containing the weld wheels, so as to maximize the effectiveness of the welding force.
While the overall arrangement briefly described above is desirable with respect to the effective use of the pressing or welding force as imposed between the weld wheels, nevertheless the overall evolution of conductive bearing assemblies as utilized in seam welders of this type has now limited the overall effectiveness and efficiency of seam welders, particularly with respect to their ability to more effectively utilize the welding force and even more specifically with respect to their ability to operate at higher linear speeds (that is, the relative speed at which the work moves through the weld nip). These conductive bearing assemblies as described above and as illustrated by
FIGS. 6-7
, have evolved so as to typically incorporate silver contact shoes immersed in oil which is part of a recirculating system so that the oil recirculates through the bearing assembly to effect proper lubrication and cooling thereof. This evolution has resulted in conductive bearing assemblies which are more efficient with respect to the bearing function and the electrically conductive function, in that such bearings have been capable of running reliably for one to two years with little or no maintenance. The significant disadvantage of this evolution in conductive bearings, however, is that these conduc
Dunn Tom
Flynn ,Thiel, Boutell & Tanis, P.C.
Johnson Jonathan
Newcor, Inc.
LandOfFree
Low inertia bearing for resistance seam welding wheel does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low inertia bearing for resistance seam welding wheel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low inertia bearing for resistance seam welding wheel will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2572762