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AssigneeCRC-Crose International, Inc.
InventorsCherie E. Kushner, Paul A. Tews, Jerome W. Nelson
Estimating the term…
Signals which contain components that vary with the lateral position of an electric welding instrument as it travels along a weld path between opposite work pieces are obtained from the arc or other heat source and are first processed to remove confusing or nonsignificant components. The processed signals are then compared or combined with each other, or with other signals of predetermined value, to obtain outputs which can be used to determine or control the lateral position or movement of the welding instrument along the weld path. Specifically, in electric arc welding of metals, signals from an electrical characteristic at the arc, such as arc current, which include a component indicative of lateral position of the welding instrument with respect to one or more sidewalls, are first filtered and processed to remove undesirable components. Under control of separate timing signals, the processed signals so obtained are sampled to derive and hold peak values indicative of extreme lateral positions of the instrument as it moves from side to side of its main travel path. By using deliberately timed control signals, these peak values are compared with each other, and/or combined or compared with other signals of known value, to obtain as output the desired position-control signals. The latter are used to indicate, control and/or to change an extreme lateral position of the instrument either by correcting its centerline of main travel and/or by modifying the width or amplitude of its lateral reciprocation.
In apparatus for performing a welding operation on a work member along a predetermined welding course, which apparatus includes a welding instrument capable of generating a characteristic composite signal having a continuous meaningful component which varies dependently with the lateral position of said instrument with respect to said course and a masking component which tends to obscure the meaningful component, said apparatus also including means for causing the instrument to travel with respect to the work member along said course and means to reciprocate the instrument through variably controllable lateral motion transversely of said course and towards and away from an extreme laterally limited position with respect to the welding course, the improved means for controlling position of the instrument with precision which comprises, in combination, the following elements:
In the method of controlling the lateral position of a welding instrument traveling along a predetermined path or course, wherein a welding current is passed through said instrument and a continuous electrical signal is generated at said instrument and in which the instrument is also reciprocated laterally back and forth across said course to extreme lateral positions defined by a variable amplitude or width of said reciprocation, thereby superimposing on said continuous signal a separate but meaningful signal related to lateral position of the instrument, thus producing a composite signal, the improvement which comprises the following steps, in combination:
Apparatus for welding which includes a welding torch, means for moving said torch along a central welding course, means for reciprocating said torch at a selected frequency and to selective amplitude transversely of said course AND towards a barrier alongside said course, means for adjusting the centering of said reciprocation motion, means for adjusting the width or amplitude of said reciprocation transversely, means for producing a first and continuous signal from the torch including a signal component variably dependent on the proximity of the torch to said barrier, means for extracting from said continuous signal a signal component which is meaningfully related in value to said proximity and having a peak value corresponding to the extreme lateral position of the torch towards said barrier and having a lesser value when the torch is at an intermediate position, timer means for isolating signal surges related the differences between to said peak value and said lesser values, means for comparing said surges with a predetermined value to produce a centering error signal, means for summing signal surges from opposite extreme torch lateral positions of reciprocation and for comparing the sum with a reference value to obtain a width error signal, and means responsive to said error signals for correcting the centering position and the width or amplitude of oscillation respectively.
Dependencies are inferred from the claim text.