Semi-automatic control and method for MIG welding

Claim 1

In a method of MIG welding in which the energization and deenergization of the welding operation is controlled from a single toggle switch having only a first and second position and in which selected operational parameters of the welding operation such as wire feed speed, arc voltage, and shielding gas are controllably varied between a first preset schedule of welding parameters and a second preset schedule in response to the position of said toggle switch, the improvement comprising: detecting the state of the toggle switch; initializing the welding operation using the first preset schedule of welding parameters in response to detection of the second position of the toggle switch; enabling a timing operation of a predetermined relatively short time duration in response to the detection of the toggle switch in its first position; detecting a reoperation of the toggle switch within said predetermined time duration for switching from said first preset schedule to said second preset schedule; deenergizing said welding operation upon the concurrence of said relatively short time duration and the absence of a reoperation of the toggle switch; repeating said reevaluation of the state of said toggle switch for reenabling said timing operation each time said toggle switch is in the first position and switching between said preset schedules each time said toggle switch is reoperated within the predetermined time duration of said timing operation.