Electric heating – Metal heating – By arc
Reexamination Certificate
1999-12-27
2001-06-05
Shaw, Clifford C. (Department: 1725)
Electric heating
Metal heating
By arc
C219S147000
Reexamination Certificate
active
06242711
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to arc welding operations manually controlled by a welder. The voltage, current and other parameters of the arc during welding are monitored and visual indicating means located within the helmet worn by the operator visually provide the operator with information to produce high quality and repeatable welds.
2. Description of the Related Art
Semi-automated arc welding is achieved by the welder manually positioning the welding rod or welding wire producing the heat generating arc to the location being welded and such welding operations include stick welding, gas metal arc welding, submerged arc welding and tungsten inert gas welding. These manual welding operations necessarily rely upon the spacing of the electrode from the weld location to produce the desired arc to achieve optimum melting of the base and welding rod or wire metals, and the quality of the weld produced is directly controlled by the skill of the welder.
Skilled manual arc welders rely upon experience to achieve the desired arc, and the operator senses the arc characteristics by the welding sound, light produced and various conditions such as splash, sputtering and the like to determine the quality and effectiveness of the weld. However, even with skilled arc weld operators, it is difficult to manually consistently maintain optimum welding characteristics, and it is very difficult to maintain quality and reliability during manual arc welding procedures. Where high quality welds must be achieved in critical applications, inspections, x-rays, and expensive secondary operations are often necessary significantly adding to the cost of quality arc welding. The cost of identifying and re-working defective arc welds is seven to eight times the cost of the original weldment.
Efforts have been made to provide the manual arc welder with information during welding to improve the quality of the arc. In U.S. Pat. No. 4,677,277, the arc current and voltage is monitored to produce an audio indication to the operator as to the condition of the arc. However, monitors consisting only of audio arc parameter indicators are hard to hear and interpolate and are not capable of achieving the desired closeness of control and quality of weld often required.
OBJECTS OF THE INVENTION
An object of the invention is to reduce the variations which may occur in manual arc welding in order to improve the quality of the weld, obtain consistent repeatability for a single operator or between operators, and reduce variations in the manual arc welding process.
Another object of the invention is to provide arc welding monitoring apparatus wherein the manual arc welding process will become more stable, testable and certifiable as to render arc welding more competitive for critical joining applications wherein real-time monitoring of the weld is possible without solely relying strictly on operator certification and welding procedures may be validated at the weldment.
Yet another object of the invention is to provide arc welding monitoring apparatus wherein operators may be able to gauge their own performance and training time is reduced as real-time feedback is provided, and the arc welder's performance can be compared with a standard, other welders, or their own historical data.
A further object of the invention is to provide manual arc welding monitoring apparatus wherein real-time quality control is achieved and reduced requirements for safety factors will produce more economical yet higher quality welds than previously attainable, and weldment re-working is reduced and the overall cost of arc welding is lowered.
An additional object of the invention is to provide an arc weld monitoring apparatus wherein real-time defect identification is achieved whereby the operator can immediately respond to weld defects and post-process inspection and testing can be reduced with attendant cost savings.
SUMMARY OF THE INVENTION
In the practice of manual arc welding processes utilizing the apparatus of the invention, a welding torch or electrode holder for welding rods or welding wire is connected to a welding power supply capable of producing the desired current and voltage for achieving arc welding. The welding process is monitored by using sensors at the point of the weld to determine the rate of welding wire feed, for instance, and on the welding power supply equipment to sense the current and voltage. This sensor information is processed by a real-time electronic monitor which performs signal analysis from the sensor information and controls the visual indicating device located within the welder's helmet adjacent the helmet viewing window. The sensors are capable of sensing the arc voltage, current, wire speed, bead temperature and bead penetration, some of these parameters being estimatable upon knowing the arc voltage and current and wire speed.
A standard welding helmet having the usual darkened viewing window through which the welder observes the welding operation is provided with visual display elements controlled by the monitor receiving the information from the various sensors at the welding power supply and the arc. These visual sensors are preferably in the form of illuminated diodes, bulbs, bar graphs, video projectors or see-through displays such as may use liquid crystal indicia or the like.
Information received by the monitor with respect to the characteristics occurring during welding may be electronically recorded using an auxiliary personal computer or networked client computer wherein this information is available for post-process evaluation, historical comparison or quality analysis.
The visual indicating means within the helmet to inform the welder of the condition of the arc can take several forms. Preferably, the indicators are visual and are either located adjacent the helmet viewing window, preferably along the lateral sides of the window as to be within the peripheral vision range of the welder, or the visual indicating information may be projected directly upon the viewing window or superimposed thereover so as to be directly in the line of sight of the welder.
With the peripherally visual indicators located at the lateral sides of the viewing window, the indicators may take the form of light emitting diodes, or incandescent bulbs, or the indicator may take the form of an illuminated bar graph peripherally visible to the welder. When light emitting diodes are used, preferably, a plurality of lights may be employed on each side of the window wherein the lights are formed in sets and may be different colors to facilitate identification. For instance, the illumination of green LEDs can indicate that the welding characteristics are within desired parameters, and if the welding characteristics depart from acceptable characteristics, the red LEDs will illuminate. Of course, the LEDs may be a variety of colors and may be lit, or extinguished, according to any desired pattern.
When using a bar graph adjacent the element viewing window, the operator is able to immediately sense ideal conditions for arc welding as the bar graph will be “centered” under ideal welding parameters, and any departure from the ideal can be immediately determined by the operator and the necessary adjustments can be made to restore the desired welding characteristics.
It is also possible to locate a small video projector within the helmet for projecting desired data upon the inside surface of the viewing window wherein the operator can see through such data while observing the welding operation. As such data will be well within the view of the operator, the desired data can consist of lights, bar graphs, or any desired configuration of visual means for indicating the welding characteristics. Likewise, rather than using a video projector for the welding indicia, it is possible to have the indicia appear on a “see-through” liquid crystal display screen or the like superimposed over the helmet viewing window upon which the desired indicia appears.
It is also within the purview of the inve
AccuData, Inc.
Shaw Clifford C.
Young & Basile P.C.
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