Patent GB-653906-A (GB)
Title: Improvements in or relating to shape-cutting machines
IPC: B23K7/00
Filed: 1948-03-09
Abstract: 653,906. Dividing by fusion. STEVENS, A. H. (National Cylinder Gas Co.). March 9, 1948, No. 7226. [Classes 83 (iii) and 83 (iv)] In a flame-cutting &c. machine a tracing head including a turntable, rotatable through 360 degrees about its axis and about a portable stabilizing base with respect to which it is radially movable, is propelled by a pair of differentially driven traction rolls astride the axis rotation of the turntable to orient a cutting torch with respect to the line of cut. A tracer A, carrying the burner nozzle is mounted for 360 degrees movement on a turntable 11 carried on a head 97 vertically swingable at one end of a radius arm 14 longi. tudinally slidable in a trunnion mounted control cabinet 88 pivoted for 360 degrees motion about a base 13 resting on a templet plate 15 having a profile rail 20 engaged between a pair of tracer rollers 19. A motor 21 driving the rollers 19 is mounted on the head 97 with the gas supply tubes 93 and electric cable also supported by a frame 94 secured to the cabinet 88. Tracer head, Figs. 10 and 14. The rollers 19 are spiral or herringbone cut to draw the head against the rail 20 and are mounted on parallel shafts 34, 35, one having a transversely movable half-bearing 39 biassed against a spring 42 by a knob 41 to adjust the gap between the rollers 19. Shaft 34 is driven direct and roller shaft 35 is rotated through an idler by a differential gear unit, Fig. 15, not shown, with a horizontal gear ring driven from the motor 21. The head 97 is supported by a roller 12 engaging ball races 31 mounted between forked limbs 18 supporting the shafts 34, 35. The turntable 11 is carried by a ring 23 pivoted to the arm 14 by a sprung pawl and ratchet or sprung ball and recess, Figs. 17, 19, not shown, to permit swinging of the head to rest on a stop on the ring 23 for burner cleaning, adjustment &c. The burner nozzle 17 has only one preheating nozzle since its orientation relative to the profile track is constant, and may be inclined for bevel cutting. A hand knob, Fig. 16, not shown, is provided for vertical nozzle adjustment through a rack 100, and for lateral adjustment a knob 104 is operated against springs 106, a scale 109 and pointer 110 being employed. Cabinet and base. A cast block 13 normally used free has screwholes 69 for bolting to the work or template especially on vertical surfaces, Fig. 2, not shown, and carries a ballbearing mounted central pivot 72 with a yoke 74 having longitudinally screw adjusted trunnions 76 for blocks 78 mounting eight ball races 79 engaging the square section radius arm 14. A stop 84 operated by a handscrew 85 is provided for locking the arm 14 which has a scale for setting-up, and a stop screw preventing withdrawal from the cabinet 88 which contains a motor speed regulating rheostat 92 and switch. Operation. The base 13 is placed on the template 15,. the nozzle height, angle, and lateral displacement, and the roller gap adjusted, the burner is lit and the motor 21 started. The head 97 runs along the rail 20 to make the cut, pushing and pulling the base 13 about the approximate centre of rotation as required. In a modification an auxiliary base, Fig. 4, not shown, rests on the work and the template is bolted to it, simple shapes, Figs. 34-40, not shown, being provided for repetition work, Fig. 44, not shown. Alternatively the base 13 is mounted on a separate standard, Fig. 5, not shown. In a form, for simple circle cutting with the arm 14 locked, the head 97 is locked by a keeper bar 139, and for use without a template a steering hand wheel 176 is provided, and an attachment is bolted to the limbs 18 and carries a heat-resistant tracer wheel on a shaft having a wheel driven by the rollers 19. In a further modification, Fig. 30, not shown, for cutting small circles a wire yoke is pivoted to the limbs 18 and carries an adjustable block having a pivot point engaged with a centrepunch mark as a turning centre.