US-12617036-B2 - Return current roller for automatic welder

US12617036B2US 12617036 B2US12617036 B2US 12617036B2US-12617036-B2

Abstract

A welding apparatus includes a welding torch mounted to a frame and electrically connectable in a source current path of a welding current source, and an electrically conductive return current roller rollably mounted to the frame a substantially fixed distance from the welding torch. The return current roller is electrically connectable in a return current path of the welding current source, and has a rim sized and shaped to roll in electrically conductive contact with an unwelded seam of a workpiece.

Inventors

Michael Kloepfer
Tom Pursley

Assignees

TITAN TRAILERS INC.

Dates

Publication Date: 20260505
Application Date: 20201215

Claims (12)

1 . A welding apparatus comprising: a welding torch mounted to a frame and electrically connectable in a source current path of a welding current source; a return current roller assembly comprising a pivotable A-shaped frame wherein a pitch of the A-shaped frame is pivotally variable, the return current roller assembly is pivotably mounted to a strut, the strut is mounted to the frame, and the return current roller assembly is rotatable about a longitudinal axis of the strut; a first electrically conductive return current roller rollably mounted in the return current roller assembly a first fixed distance from the welding torch, and second electrically conductive return current roller rollably mounted in the return current roller assembly a second fixed distance from the welding torch, wherein the first return current roller and the second return current roller are each electrically connectable in a return current path of the welding current source, and respectively have a first rim and a second rim each sized and shaped to roll in electrically conductive contact with an unwelded seam of a workpiece, and wherein the frame is coupled to a moveable rail for movement of the welding torch and the return current roller assembly together along the unwelded seam on a same side of the workpiece.
2 . The welding apparatus of claim 1 , wherein, when the welding apparatus is in use: the first return current roller is operative as a first return current electrode in a first return current path between the welding torch and the welding current source; and the second return current roller is operative as a second return current electrode in a second return current path between the welding torch and the welding current source.
3 . The welding apparatus of claim 2 , wherein: the first return current path has a first fixed return current path length based on the first fixed distance; and the second return current path has a second fixed return current path length based on the second fixed distance.
4 . The welding apparatus of claim 1 , wherein: a first profile of the first return current roller rim matches a profile of the unwelded seam of the workpiece; and a second profile of the second return current roller rim matches the profile of the unwelded seam of the workpiece.
5 . The welding apparatus of claim 1 , wherein the first return current roller is circumferentially tapered to form a first V-shaped rim, and the second return current roller is circumferentially tapered to form a second V-shaped rim.
6 . The welding apparatus of claim 1 , wherein, when the welding apparatus is in use: the first fixed distance is between a first contact point of the first return current roller with the unwelded seam and a welding point of a welding torch tip of the welding torch in the unwelded seam; and the second fixed distance is between a second contact point of the second return current roller with the unwelded seam and the welding point.
7 . The welding apparatus of claim 1 , wherein the strut comprises a suspension device comprising a strut rod, wherein the strut is mounted via a bracket to the frame, wherein the strut rod is coupled for sliding movement relative to the suspension device, to vary a position of the return current roller assembly along the longitudinal axis.
8 . The welding apparatus of claim 7 , wherein the suspension device is operative to urge extension of the strut rod from the suspension device.
9 . The welding apparatus of claim 7 , wherein the suspension device comprises a coilover.
10 . A welding system comprising a plurality of welding apparatus of claim 1 , wherein the frame corresponding to each of the plurality of welding apparatus is coupled to the moveable rail.
11 . The welding apparatus of claim 1 , wherein the welding torch and the return current roller assembly are respectively mounted to the frame on a same side of the frame.
12 . The welding apparatus of claim 1 , wherein the welding torch and the return current roller assembly are respectively positioned for alignment of the electrically conductive contact of the respective rims of the first return current roller and the second return current roller, and a welding point of a welding torch tip of the welding torch with the unwelded seam on a same side of the workpiece.

Description

RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application Ser. No. 62/948,412 filed on Dec. 16, 2019, the entire disclosure of which is hereby expressly incorporated by reference. FIELD The present disclosure relates generally to automatic electric welding machines, more particularly to automatic arc welding machines, and even more particularly to return current techniques in automatic arc welding machines. BACKGROUND Automatic electric welding machines (hereinafter, simply “welding machines”) are widely used in industrial fabrication to join metal workpieces where the relative disposition of the workpieces and the configuration of the seam to be welded are sufficiently simple so as not to require the skill of a human welder. For example, automatic welding machines are widely used to join abutting flat panels which form a generally linear seam. In some configurations, the panels are laid flat on a supporting surface to form seams to be welded. A welding head of the welding machine is suspended above the panels. The welding head and panels are moved relatively such that the welding head traverses the seam. For example, the welding head may be supported by a frame which is movably mounted to a gantry or rail. Alternatively, the welding head may be fixed, while the supporting surface of the panels is movable. In either case, the welding head and panels may be moved relatively to cause the welding head to travel along the seam, so as to enable welding along a length of the seam. For example, U.S. Pat. No. 9,012,809 to Melin et al. teaches a welding device and a central element configured with sensor members to register geometric properties of a spacing between the work pieces. An auxiliary sensor means registers a vertical distance between the welding head and a bottom surface of the spacing between the work pieces. The auxiliary sensor means has a roller member attached to the central element including a lever-type design allowing the auxiliary sensor means to pivot around a pivoting point, to maintain contact between the roller member and the bottom surface during transport of the device along an operating direction. It is not taught, however, how the welding device is grounded. In some configurations, the workpiece edges are overlapped. For example, in U.S. Pat. No. 5,726,410 to Fukushima et al, overlapping edge portions of the workpieces to be welding are squeezed together by roller electrodes with a welding current being applied between the roller electrodes. The roller electrodes are thus provided on opposite sides of the plate-like workpieces. It remains commercially desirable to develop further improvements and advancements in automatic electric welding, to overcome shortcomings of known techniques, and to provide additional advantages. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments will now be described, by way of example only, with reference to the attached Figures. FIG. 1 is a front perspective view of a welding apparatus including an electrically conductive return current roller. FIG. 2 is a side perspective view of the welding apparatus of FIG. 1. FIG. 3 is a side elevation view of the welding apparatus according to FIGS. 1-2. FIG. 4 is a front perspective view of a return current roller assembly according to FIG. 3 in isolation. FIG. 5 is a front elevation view of a return current roller assembly as disclosed herein including an enlarged view of a return current roller having a circumferentially tapered V-shaped rim in conforming contact with an unwelded seam of a workpiece. FIG. 6 is a side elevation view of two return current rollers according to FIG. 5, rolling in electrically conductive conforming contact with a workpiece. FIG. 7 is a figurative side elevation view of a welding apparatus having a welding torch electrically connected by a welding current lead to a welding current terminal of a current source, and return current roller rollers electrically connected by a return current lead to a return current terminal of the current source. Throughout the drawings, sometimes only one or fewer than all of the instances of an element visible in the view are designated by a lead line and reference character, for the sake only of simplicity and to avoid clutter. It will be understood, however, that in such cases, in accordance with the corresponding description, that all other instances are likewise designated and encompassed by the corresponding description. DESCRIPTION Techniques for providing a return current path for an automatic electric welding apparatus are disclosed herein. In particular, disclosed herein are techniques for a welding apparatus 100 for use in performing any suitable welding, including but not limited to, electrical welding, including arc welding, including shielded metal arc welding, gas metal arc welding, flux-cored arc welding, gas tungsten arc welding, plasma arc welding, or automatic welding. FIGS. 1 and 2 illustrate perspective views of