Patent GB-758242-A (GB)
Title: Improvements in or relating to automatic machine control devices
IPC: G05B19/14
Filed: 1952-07-08
Abstract: 758,242. Copying-machine-tool details. KILLIAN, C. H. July 8, 1952, No. 17138/52. Class 83 (3). [Also in Group XXIII] An automatic machine-control device comprises a tape 58 having perforations therein according to a code, a co-operating pin sensing- mechanism 70 and a selsyn motor connected, through contacts operable by the pins, with a transformer. The device may control a lathe, or a milling, planing, boring, copying or sawing machine. The tape may have several columns of the code, each column controlling a selsyn, each selsyn being connected, directly or indirectly, to a screw, rack-and-pinion, or worm for rotating, translating or indexing a slide or table. A reversing switch PR, which may be operated by collars 120, 121, Fig. 10, on a manually-operated rod 51, enables the cutter always to travel forwardly regardless of the direction of movement of the tape feeding-rolls 49 to enable, for instance, climb or conventional milling to be employed. The tape may be made of longfibred sulphite paper, cellulose acetate, impregnated poplin &c., steel, brass, &c. The tape shown in Fig. 3 has twelve sets of perforations, the two centre sets of which may control the tape feed-mechanism; and it is designed for advancing a feed-screw on a machine tool by 0.002 inch increments for the machining of a right-angled corner whose sides slope at 45 degrees. Curved shapes may be considered as a number of short straight sections. The tape is fed by sprockets 60, 62 which may, or may not, be fully intermeshing. Pockets at the bases of the teeth prevent the tape being held frictionally, and receive any burr. Alternatively, the sprocket-shafts 61 may be slightly separated by cam means when the tape is stationary. The sprockets are rotated intermittently by Geneva mechanisms 18, 59, Fig. 8, the members 59 being rotated from a motor through shafts 10 or 11, Fig. 1, or independently by hand or power. The tape is fed to the sprockets by rolls 49 bearing sprockets 47<SP>1</SP>, and rotated by the motor through a clutch or belt drive, a main shaft 10, and gears 14, 41-45 and 47, Figs. 10 and 12. Either of two gears 50 on the axiallymovable reversing shaft 51 engages a gear on one of the rolls 49 to rotate the frictionallydriven reeling drums 55. The reeling-mechanism is started by a button 124 and is stopped in either direction of movement by the tape and associated switching devices SD, SR, 120, 121. The sensing-pins 70, Figs. 7, 9 and 14 (diagrammatic), are spaced apart by the same distance as the groups of perforations (e.g. Group 9, Fig. 3). Each pair of pins is carried on a shaft 71 which is mounted on a carriage 30 advanced by eccentrics 17 on the shaft 10 through links 29. As the shaft 71 is advanced it is rocked as one of the pins engages a hole and the movement is exaggerated by co-operating wedges 80, 81, the wedge 80 being formed on a member 72 pivotally linked to the sensing pin carrier 75. The pins are centralized by spring plungers 79. Centralizing bars 101 may also be provided. Movements of the members 72 control the positions of gags on a carriage 20, which is reciprocating through links 19 by eccentrics on the shaft 11 opposed to the eccentrics 17 on the shaft 10 for the sensing- carriage 30. (Alternatively, the shaft 11, or both shafts, may carry the eccentrics, or the carriages may be reciprocated by cams.) The carriage 20 carries a gag 100 corresponding to each pair of sensing pins. Each gag operates a switch-operating device through members 102 which may be linked by rocker arms. The members 102, Figs. 8 and 9, rock arms 111 freely mounted on the shaft 11 to actuate switches 110. The switches are maintained in operative position by corrugated springs 113 or by corrugations in the switch arms themselves. The switches cause a movement of a selsyn to control the machine. The change-over from one set of switch connections to another is assisted by inserting a high resistance into the circuit during the change-over. The resistance is then cut out by a cam on the main shaft 10. Alternatively, two resistances operated sequentially by two cams on the shaft 10 may be used, the cams being driven through a pin-and-slot lostmotion connection so that, when the shaft is reversed in rotation, the resistances are still switched in at the correct times. Dowel bolts f allow the upper part of the frame to be raised for free access to the tape. Specification 758,322 is referred to.