GB459292A - Electric arc cutting machine - Google Patents

Abstract

459,292. Dividing by fusion. STROBEL, K., 601, North Greenleaf Avenue, Whittier, California, U.S.A. July 3, 1935, No. 19054. [Class 83 (iv)] [See also Groups XI, XXIII, and XXXV] In an electric-arc cutting machine of the kind in which an electrode provided with an elongated edge such as a disc or endless band has imparted to it a unidirectional movement with respect to the work, the arc is controlled magnetically by a coil so located that elongation of the arc at the sides of the electrode is avoided and the arc confined between the edge of the electrode and the work. The arc is sufficiently wide to ensure removal of the metal, the sides of the cut being clear of the sides of the electrode. Cutting is also effected without heating the metal on either side of the cut. The work 6 is secured in a vice 4 over a slot 5 in a table 2 connected to one terminal of the supply, the other terminal of which may be connected to a toothed disc 7 rotated at a high speed, e.g. 5000 r.p.m. for an 18" disc, either direct or through gearing by a motor 9 bolted to a slide 28, which may be traversed on a guide 34 by a screw 39. The guide is vertically adjusted at one end by a screw 42, the other end being similarly adjusted or being connected to a slide 45 attached to a counterweighted chain or cable 47. Secured to the motor frame is a non-magnetic guard 18 for the disc, which carries an adjustable spring-pressed contact brush 25 engaging a conducting ring 17 pressed against the side of the disc 7. The disc is mounted on its shaft 8 through insulating rings 12, 15 and bushing 13. The disc has a saw edge and the arc is struck either by contact of the teeth with the work or by bridging the gap by a wire brush, or by laying a strip of carbon &c. in advance of the work so as to start the arc initially between the carbon and the disc. The arc is struck between the work and the points of the teeth which assist in drawing the fused parts of the work in the direction of movement of the disc. The ends of the teeth are swaged out to provide the greatest width of the disc so that the arc is of sufficient width to effect the cut while keeping the sides of the disc clear thereof. The arc is confined between the edge of the disc and the work by a magnetic field created by a coil 54 wound in the form of a tapered helix, the taper of which is directed towards the edge of the disc. This coil may be connected in series with the disc, the current passing from terminal 61 through switch 62, current limiting resistance 63, coil 54 and then by strap 60 to the brush 25. The slide 28 may be traversed by hand, but in order to keep the length of the arc constant it may be traversed by a motor 70, the armature of which is connected across the arc and the field 72 connected to a constant source of energy.