Method and apparatus for initiating gas scarfing

Claim 2

A method as claimed in claim 2 wherein prior to initiation of the method the electrode is positioned at an angle with respect to the workpiece, and, upon initiation of the method, the electrode is fed toward the workpiece simultaneously with the energization of an electrical circuit for controlling the melting of the electrode and with the initiation of the rotative motion of the electrode, and wherein, after a predetermined time delay, the gas stream is started simultaneously with the return of the electrode to the initial position thereof.

Claim 3

In an oxygen scarfing machine, an arrangement for initiating an oxygen scarfing process during the movement of the workpiece to be scarfed relative to the scarfing machine, said arrangement comprising a movable, consumable electrode for forming a deposit of metal on the workpiece, feeding means for feeding said electrode towards a selected point on the workpiece in a direction opposite to the movement of the workpiece relative to the machine, melting control means for causing melting of said electrode to form a deposit of high temperature metal at said selected point, a holder for said electrode, and means for moving said electrode holder relative to the workpiece in the same direction as the movement of the workpiece relative to the scarfing machine so that said electrode maintains contact with the said selected point on the workpiece during the movement of the workpiece relative to the scarfing machine such that continuous melting of a portion of said electrode causes the formation of a deposit of the electrode material at the said selected point during the movement of the workpiece relative to the scarfing machine.

Claim 4

An arrangement as claimed in claim 4 further comprising an oxygen nozzle, and control means for controlling the movement of the holder and the operation of the oxygen nozzle, said holder, said nozzle, and said control means being mounted on a carriage movable alongside the workpiece.

Claim 5

An arrangement as claimed in claim 4 further comprising means for pivotably supporting said electrode holder to permit rotative motion thereof relative to the workpiece, rotative motion control means for causing pivoting of said electrode holder toward the workpiece at a speed approximately equal to the speed of the relative movement between the workpiece and the scarfing machine, oxygen supply control means for controlling the supply of oxygen for scarfing, and an electrical control circuit for controlling said feeding means, said melting control means, and said rotative motion control means such that the feeding of said electrode is begun simultaneously with the energization of said melting control means and with the initiation of the rotative motion of said electrode holder toward the workpiece, and for controlling said oxygen supply control means, said melting control means, and said rotative motion control means such that the melting of said electrode is interrupted simultaneously with the initiation of an oxygen stream and with the return of the electrode holder to the initial position thereof.