| 摘要 |
1, 084, 630. Programmed control of machine tools. GENERAL ELECTRIC CO. June 21, 1966 [June 21, 1965], No.27648/66. Heading G3N. A numerical control system, wherein a velocity command 10, a function generator 11 and distance counters 12, 13 are controlled in a known manner from a source 14 responsive to a programme tape, has facilities provided for selecting by a switch 15 a signal MV whereby it is run at a maximum velocity. Considering the Y system only, motion pulses from the distance counter 12 are fed to a count-up gate of a Y-axis limit counter 16 and are registered on the occurrence of trigger pulses C2 during the first half cycle of each motion pulse. The maximum velocity pulse rate, derived from a source 18, is applied through an AND-gate 20 to the countdown gate of the counter 16. The AND-gate 20 is controlled by a gate 24 which closes it when a count of 8 is reached. The X-axis system is similar to the Y-axis system and has a limit counter 17. When both counters 16, 17 are in their 8 or 9 count condition, a gate 23 is opened to feed pulses from an enabling source, of higher frequency than source 18, as the maximum velocity signal MV to the function generator 11. The output of function generator 11 is in the form of bursts of pulses having an average pulse rate equal to that of source 18. |
