| 摘要 |
645,406. Control systems for high-frequency apparatus. BRITISH UNITED SHOE MACHINERY CO., Ltd. July 12, 1947, No. 18602. Convention date, July 16, 1946. [Class 38 (iv)] [Also in Groups VIII, XI and XL (c)] In a control system for supplying highfrequency electrical energy to a variable-speed machine for seaming non-metallic sheet material (see Group VIII), an oscillator M is arranged to supply a pulse of determined duration at each rotation of a switch 76 which is geared to the feed mechanism of the machine and includes a conducting segment 83 adapted to shortcircuit contacts 77, 78, 79 for a part of each revolution. High voltage power is supplied to oscillator M through a modulating valve 64 which is biassed beyond cut-off due to current flowing in a resistor 105, except immediately after the contacts are open-circuited when the current through resistor 105 is interrupted while a condenser 100, in a pulsetiming circuit including a voltage regulator 68 and a variable resistor 101, is charged up. During this charging period a pulse of high frequency energy is delivered ; resistor 101 can be regulated to control the pulse duration. Specification 613,419 is referred to. |
