GB534714A - Improvements in or relating to oxygen jet cutting machines - Google Patents

Abstract

534,714. Cutting by fusion. HANCOCK, L. J. Oct. 28. 1939, No. 28886. [Class 83 (iv)] The burner of a flame cutting machine is automatically kept at a substantially constant height above the work by a reversible electric motor, which raises or lowers the burner through gearing and which is controlled by two electric relays and one or more runners which contact with the surface of the work and control the energization of the relays. The burner 3 which is slidable in the holder 2 or attached to a slide at the end of the arm 1 of a profile cutting machine has secured thereto a carrier 7 connected by a push-pull rod 5a to a rack 5, which may be reciprocated either by a hand wheel or by reducing gear from a reversible electric motor 22. To the carrier are secured a pair of tubes 8 connected by a U-shaped yoke 9. Through the tubes pass a pair of rods 10 which are rounded or provided with ball ends 11 to engage the work and to which may be secured a ring 19 having one or more additional legs 20 to avoid failing of the control device by the runner passing over the edge of the plate. The upper ends of the rods are connected by a yoke 12 and an extension 14 is provided on which is adjustably mounted a non-conducting screwed sleeve 15 having a conducting inset 16 forming part of a switch and co-operating with blade springs 18 in a switch box 17 secured to the burner. The inset 16 contacts with the centre spring and either of the outside springs when the runners pass over uneven or inclined surfaces of the work and so the motor is rotated in one or the other direction. When the desired position of the burner is reached the switch is in neutral position and the motor stops. The switch is in a battery circuit energizing one or the other of two relays so as to energize the armature of the motor in one or the other direction and also to energize the field. If the rods 10 pass beyond the edge of the work they fall and the inset 16 falls below the centre spring and the motor stops. In a modification for cutting round bars the carrier is provided at each side with cross bars 32. 34 with reduced ends 33 serving as pivots on one or the other of which are applied by notches 38 the levers 36. These levers, which have rounded ends 40, are connected together by a cross bar 37 and are provided with projections 39 engaging projecting feet 35 on the rods 10 so as to operate the switch. When the position of the levers 36 becomes such that the ends 40 can fall away from the work surface the runners 11 on the ends of the rods maintain the control. The rack and pinion may be replaced by screw and nut mechanism.