Electric heating – Metal heating – By arc
Reexamination Certificate
2002-10-10
2003-09-30
Elve, M. Alexandra (Department: 1725)
Electric heating
Metal heating
By arc
C219S136000
Reexamination Certificate
active
06627848
ABSTRACT:
The present invention relates to the art of welding, and more specifically to a welding guide for an electric arc welding gun or torch.
While the present invention finds particular utility in connection with a guide for use with an electric arc welding gun and, accordingly, will be described in detail herein in connection with such use, those skilled in the art will recognize that the invention may have other applications and could be utilized, for example, in welding operations that use other kinds of torches.
BACKGROUND OF THE INVENTION
Welding processes are widely used in modem day manufacturing. One such welding process is commonly referred to as arc welding, which utilizes an electrical current and a welding wire. In many instances, arc welding is achieved through the use of a welding gun which facilitates manipulation of the welding wire by a workman during welding. The following patents are incorporated herein by reference as background information with regard to such electric arc welding guns: U.S. Pat. No. 5,384,447 to Raloff, et al.; and U.S. Pat. No. 2,790,925 to Landis, et al.
One example of an arc welding gun of the prior art is shown in the aforementioned patent to Raloff et al. and, generally, comprises a handle member connected to an end of a composite cable which delivers arc power from a suitable source. The welding gun, although comfortable to hold, requires the operator to support the entire weight of the welding gun. In addition, most welding situations require the operator to manually maintain a constant distance between welding wire and workpiece. Other factors, such as welding wire feed rate and welding wire extension also must be considered and controlled during the welding process. This is necessary to achieve a balance between the melting and welding wire core materials in order to produce the desired weld bead. Maintaining control and consistency of the aforementioned welding variables is extremely difficult for the novice welder and/or the experienced welder encountering awkward welding positions.
Another variable that has an effect on welding performance is the welding wire angle. The welding wire angle can be used to control the weld pool. In this respect, for example, by tipping the welding wire at an angle opposite to the direction of travel, known as the drag angle, the arc force can be used to counteract the force of gravity which tends to cause the molten weld pool to run ahead of the arc. The drag angle is the angle between the welding wire center line and the seam center line in the direction of travel. Positioning of the welding wire is critical to ensure good weld bead shapes. For each welding situation, a prescribed drag angle is recommended depending upon the thickness and type of materials to be welded.
Additionally, horizontal fillet welds commonly found on lap welds require that the electrode point at the bottom plate in a manner such that the angle between the electrode and bottom plate is less than 45°. This angle is commonly referred to as the welding wire-to-joint angle. The novice welder has a difficult time in attempting to maintain a consistent drag angle and welding wire-to-joint angle. In addition, the experienced welder encountering difficult welding situations may also find it difficult to maintain consistent angles.
Performance characteristics of electric arc welding include such operational features as welding position capability, deposition rate, penetration, slag covering, and weld spatter. Welding position capability is influenced by weld puddle size, slag volume, electrode diameter, and current capacity. Control of many of these operational features requires the operator to continuously observe the position of the welding gun and welding wire relative to the workpiece.
Another variable critical to ensuring good weld bead shapes is travel speed along the workpiece. Travel speed is necessary to handle the molten metal and slag to produce a desired weld size. Uniformity of travel speed is important. It is accomplished in part by maintaining a uniform distance between the welding wire and the molten slag behind the wire. The novice welder at times will find it difficult to maintain a uniform travel speed throughout the welding operation. Likewise, the experienced welder may find it difficult to maintain uniform travel speed where the welding position is awkward.
Because of the aforementioned characteristics, among others, it is desirable to provide a device which assists the inexperienced welder, as well as the experienced welder, in maintaining desired positions of a welding gun relative to a workpiece during a welding operation while, preferably, enabling viewing of the welding area, thus to optimize controlling the welding variables. The present invention provides such a device.
SUMMARY OF THE INVENTION
The present invention provides an improvement for welding devices of the type described which overcomes the above referred to difficulties and others, and is easy to use. More particularly in this respect, a guide device is provided for the welding end of an electric arc torch having an insulator surrounding a contact tip through which a welding wire extends. The welding guide device is comprised of a sleeve having a first end for receiving the insulator and a second end extending outwardly of the contact tip and through which the welding wire extends. In accordance with one aspect of the invention, the second end includes a portion which is slidable along or between workpieces as the welding torch moves along the welding path. The guide device is structured to slidably engage a workpiece to enable an operator to slide the welding gun along workpieces while maintaining a desired position of the welding gun and welding wire relative to the workpiece. Preferably in this respect, the second end of the welding guide includes a rib on the exterior side and/or an edge which is slidable along or between workpieces, thus allowing the operator to support and slide the welding gun along a welding seam and maintain a straight weld path. Advantageously, the use of the welding guide device for resting the welding gun upon a workpiece also relieves the operator from supporting the entire weight of the welding gun. This reduces operator fatigue and, consequently, improves efficiency of the welding operation. In addition, the welding operator is able to maintain a straight weld path during occasions when maintaining visual contact with the welding arc is difficult or prohibited.
In accordance with another aspect of the invention, the second end of the guide includes a window or opening which allows viewing of the contact tip, welding wire, and welding arc as the operator advances the gun along a weld path. This advantageously optimizes maintaining control over those operational features which require continuous observation during the welding process.
It is accordingly an outstanding object of the present invention to provide a welding guide attachment for a welding gun which assists the inexperienced welder, as well as the experienced welder, in maintaining desired positions of a welding gun relative to a workpiece during a welding operation.
Another object of the present invention is the provision of a guide device of the foregoing character that has a viewing opening in order to enable the operator to maintain visual contact with the welding arc and which facilitates operator inspection of welding wire as it exits the contact tip of a torch and allows an operator to observe welding wire stickout during a welding operation.
Still another object of the present invention is to provide a welding guide of the foregoing character including a guide structure for resting upon a work surface to assist an operator in maintaining desired welding performance conditions such as, for example, constant travel speed, constant drag angle, constant welding wire-to-joint angle, constant distance between welding wire and base metal, and a straight path of travel.
A further object of the invention is the provision of a welding guide device which is si
Elve M. Alexandra
Fay Sharpe Fagan Minnich & McKee
Kerns Kevin P.
Lincoln Global Inc.
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