| 摘要 |
737,397. Removing metal by spark discharge. METHOD X CO. Oct. 23, 1952 [Nov. 14, 1951], No. 26605/52. Class 83 (4). In apparatus for cutting a workpiece by repeated spark discharges across the gap between the work-piece and an electrode having a condenser across the gap a grid-controlled discharge tube is connected between the condenser and a source of charging current therefor, to isolate the condenser after charging thereof from the charging source until after the condenser has discharged and means are provided to render the tube conducting at a predetermined time after the condenser discharges. A condenser 2 supplied from a source 6 is connected one side to a manually adjustable electrode 32 maintained above a workpiece 22 in a dielectric liquid, e.g. kerosene or transformer oil, and the other side to the workpiece. A triode 3, e.g. a thyratron, is connected in one lead from the source 6 to the condenser in series with a pulseforming network 4 comprising a condenser 44, a resistor 46 and an inductor 42. The triode grid is connected to a delay device 5 comprising a simulated transmission line. A resistor 48 is joined between the triode grid and cathode. In operation with the condenser 2 charged and the triode deionized and non-conducting the electrode is advanced to the workpiece until the condenser discharges in a spark across the gap. The gap is deionized quickly since it is isolated from the source 6. As the condenser discharges an impulse from the device 5 is applied after a time delay to the triode grid. The triode fires and becomes conducting and the condenser 2 is charged from the source 6 through the triode. The triode is deionized by the network 4 when condenser 2 is charged. |
