Patent GB-580440-A (GB)
Title: Photo-electric control mechanism for flame-cutting devices
IPC: B23K7/00
Filed: 1944-01-17
Abstract: 580,440. Control of two motors. TANDLER, W. S., and WALKER, D. S. Jan. 17, 1944, No. 903. [Class 38 (iii)] [Also in Groups XXII and XL] A flame-cutting device or torch is made to follow a predetermined path, such as M N P Q R M, Fig. 5, by means of two motors controlled photo-electrically to operate alternately by predetermined optical records driven by the motors, one motor driving the torch in a longitudinal direction, and the other motor driving the torch in a transverse direction, so that the path is traced in a series of steps which may be made to approximate as closely as desired to the theoretical path. General construction. The torch machine shown in Figs. 1-3 comprises a carriage 42 with rollers 43 driven longitudinally on rails 44 by means of a rack and pinion 48, 47, the pinion 47 being geared to a motor 46 on the carriage. An arm 17 extends transversely from the carriage 42, and the torch 11 is mounted on a bracket 15 slidable along the arm 17. The bracket 15 is connected to tapes 13, 13a, the tape 13 being wound and fastened to a drum 14, and the tape 13a being wound and fastened to a drum 14a but passing over a drum 16 at. the end of the arm 17. The drums 14, 14a, are fast with each other and are driven as one by a motor 20 on the carriage 42. A photo-electric scanner 26 is driven through a reversible clutch 24 by the motor 20, so that the' motion of the scanner 26 is proportional to the motion of motor 20 and to the transverse motion of the torch. Similarly, a photo-electric scanner 51 is driven through a reversible clutch 53 by rack and pinion 48, 52, so that the motion of the scanner 51 is proportional to the motion of the motor 46 and to the longitudinal motion of the torch. Photo-electric scanners. The photo-electric scanner 26 comprises a drum with three spiral optical record tracks 27, 28, 29 opposite three sets of lamps and photo-electric cells 31, 32, 33 connected to an amplifying and relay box 41. The sets of lamps and cells are moved by a screw and nut device geared to the drum so as to follow the spirals of the tracks. The photoelectric scanner 51 is similarly constructed, and its three similar tracks are shown in Fig. 7. General operation. The machine having been adjusted for the starting point M, Fig. 5, of the path to be traced, the motor 46 is started to drive the torch from M' to N. At this point, mark n of track 54 affects its photo-electric circuit and causes motor 46 to stop and motor 20 to start thereby to drive the torch from N to P. At this point a mark on track 27 causes motor 20 to stop and motor 46 to start, and subsequent marks on tracks 54, 27 cause a series of steps to be made to move the torch from P to Q via P1, P2, P3. Just before Q is reached, a mark on track 28 (similar to r<1>, Fig. 7) causes motor 46 to be set for reverse operation while scanner 51 is set to keep its forward movement; then when Q is reached, a mark on track 27 causes motor 20 to stop and motor 46 to start in reverse direction to move the torch from Q to R. After this a set of steps is again performed in the desired directions to move the torch approximately along the desired path from R to M. If it is desired that the operation should stop at any point of the path, this is performed automatically by a mark, e.g., r"4 on the track 56 or 29 according to which motor is in operation at the time. After this stoppage, the machine is restarted by a hand switch to continue the tracing of the path. If it is desired completely to stop the machine at any point, this is performed automatically by means of two marks, e.g., m"1, one on each track 56 and 29. The control marks may be made by hand operation of the motor controls to make the torch perform the desired sequences of movements. The complete circuit arrangements are described with reference to Figs. 8A, 8B (not shown).