GB858819A - Control of automatic flame-cutting machines - Google Patents

Abstract

858,819. Photo-electric guiding and checking devices. BRITISH OXYGEN GASES Ltd. July 6, 1959 [July 11, 1958], No. 22346/58. Class 40(3). [Also in Group XXII] An automatic flame-cutting machine has at least two photo-electric devices 17 connected in parallel and disposed at different angular positions about the axis of the cutting torch 16 whereby light emitted during cutting impinges on all the devices and means are provided for stopping the motion of the torch when the combined output of the devices indicates loss of cut or extinction of the pre-heat flame. The torch 16 is carried by a cutting head 10 mounted for transverse movement along a beam 11 by an electric-motor 12 and for longitudinal movement along guides 13 by an electric motor 14. Both motors are controlled from a unit 15 which receives signals from a prerecorded record, e.g. as described in Specification 840,235. Alternatively, the torch may be guided by a template or by a line traversed by a photoelectric device. Two photo-electric devices 34, Fig. 3, spaced not less than 90 degrees and preferably 180 degrees, apart are clamped at 33 on a bracket 31, 32 carried by the torch 30. Each device comprises a photo-electric cell 35 housed in a body 36 and which receives direct light only from the cutting zone through apertures 42, 38, transparent shield 43 and quartz rod 39. In another embodiment, Fig. 2 (not shown) each cell is mounted at the end of a long straight tube inclined to the nozzle axis. An optical system may also be associated with the photoelectric devices. If loss of cut or pre-heat flame occurs the signal from the devices 17, Fig. 1, acts through relay 18 to stop movement of the torch and may also control the gas supply thereto.