Patent GB-541984-A (GB)
Title: Improvements in flame cutting metal bodies
IPC: B23K7/00
Filed: 1940-08-23
Abstract: 541,984. Blow-pipe burners. LINDE AIR PRODUCTS CO. Aug. 23, 1940, No. 13361. Convention date, Oct. 19, 1939. [Class 75 (i)] [Also in Group XXII] In flame cutting hot or cold ferrous metal bodies of large cross section such  as ingots, blooms, billets, bars, beams and channels, at least one high temperature jet is projected against the surface of the body and automatically and recurrently swept along the surface at such high velocity that the jet penetrates only partially through the body. The body may then be severed at a high speed which keeps pace with the rolling, drawing or like operations thereon. The torch may consist of a blade B, resembling a saw and having a series of closely spaced forwardly inclined nozzles 40 for cutting oxygen. It is provided with water cooling connections 46, 52 and is secured to a frame F reciprocated over the work W in guides on a member 23 vertically adjustable on a support 24 by a link 11 and lever 10 from a cam C driven by a motor M through variable speed gear T adjustable by a handle 70. The pivot bolt 17 of the lever is adjustable in slots in the lever 4 in the framing and is secured in position by a block 18 and nut 19 to vary the stroke of the lever. Each nozzle may be reciprocated right across the work or over a path at least equal to the space between adjacent nozzles. Against the back of the blade B is pressed by a spring 43 a floating slide valve 42, having a chamber 41, communicating with the oxygen supply through a solenoid operated valve 58 the length of the chamber being varied by an adjustable member 44 according to the width of the work so that the nozzles are only open to the chamber when in line with the work. The member 23 is vertically adjustable by a screw 25 which may be initially operated by a hand wheel 27. Automatic feed of the blade as the work progresses is effected by rotating the ratchet nut 26 by a spring pressed pawl 62 carried by the frame F. The vertical feeding rate of the blade is varied by a masking pawl 65 mounted on a hand adjusted screw 73 on the member 23. A pre-heating blowpipe 56 is secured to a bracket 57 connected to the member 23. The work is secured on a tiltable support H provided with a projection 30 pivotally connected to a link 31 which is pivoted on a projector 32 of the member 23 so that at the beginning of the cut the work is tilted forwardly and at the end of the cut is,tilted rearwardly to prevent the formation of uncut fins at the bottom of the kerf. Alternate nozzles may be laterally inclined in opposite directions or the ends of each nozzle may diverge so as to form a kerf which is wider than the blade. The blade may have a toothed edge as shown so as to provide space for the flow of slag or may consist of a series of tubes soldered in the walls of a hollow blade and flush with or projecting from the lower edge which may be upwardly sloped to provide the space for flow of slag. When the body has been preheated by blowpipe 56 the motor is started by depressing a fresh button switch 71, the circuit to the valve 58 being then completed by a switch 59 operated by the cam C to turn on the cutting oxygen, the valve being open during the forward stroke and closed during the rearward stroke. In another form two adjacent sets of nozzles may be used directed forwardly and rearwardly respectively to operate on opposite strokes. In a further form the blade, Figs..9 and 14, may consist of a rotatable disc D mounted on a platform 54 permanently fixed or having wheels X provided with brakes 53 for engaging tracks Y, the work W being passed from a rolling mill over rollers R between guides 33. The disc which has radial passages 117 with substantially tangential discharge portions 39 and may have a smooth or toothed edge, is mounted on a member S pivoted at 110 on the platform and provided with a counterweight 109. The disc is carried by a hub 112 rotatably mounted on a hollow shaft L fixed in the end of the member S. The hub communicates via the shaft L with a valve controlled oxygen supply hose 119, the oxygen passing from the hub to the disc through tubes 115 and valves 114 provided with rollers running on an adjustable cam track 136 carried by the member S so that the nozzles are only in action when they are traversing the work. The member S is moved about its pivot 110 by a cam Z driven by a belt 106 from a motor E and the disc D is driven by bevel gear 126, 123 and pinion gear 122, 121 by a motor N through a slip coupling 55 which slips at slightest overload such as if one of the teeth 134 strikes the work. The member S also carries a preheating blowpipe 132 or one on each side of the disc, the blowpipes being pushed forward by fluid pressing cylinders 139 controlled by valve 209 and provided with a guide wheel 144 for engaging the work to maintain the blowpipe at a pre-determined distance therefrom. The gas supply to the blowpipe is controlled by a valve 210. The shaft L carries at its other end a slotted block 147, Fig. 15, provided with a switch 148 which is operated by a pin 152 on a spring controlled arm 150 carrying a shoe 151 when this engages the work. To perform the cutting operation a push button switch is closed to operate a solenoid which causes the motor E to be set in operation to bring the disc D down to the work. The shoe 151 thus engages the work and then closes the switch 148 to stop the motor E and energize relays through which the solenoid operated valve 209 is actuated to admit air to the cylinder 139 and solenoid operated valve 210 is operated to supply preheating gases to the blowpipe 132. Another push button switch is then operated to close relays for causing operation of the valve 207 to turn on the cutting oxygen and for starting the motor N. Another switch now automatically closes to start the motor E again to feed the disc to the work as the cut progresses. When the work is secured and the disc has been returned to starting position a switch 155 is opened by a projection 154 on the member S to secure the motors N and E to stop and to start off the gases to the disc and pre-heating blowpipe and thus stop the machine. If during cutting it is desired to stop the machine the circuit is broken by depressing a normally closed push button switch and the motor N is then reversed by operating another push button switch. In a modified form of disc the passages 39 consist of projecting tubular inserts 50, Fig. 11, which may be bent slightly at mid-section to give the jet a lateral component of motion. Successive nozzles may be shifted in opposite directions. Alternatively each of the teeth 134 may have a pair of discharge passages branching outwardly from each passage 117. In another form the disc may be carried by a shaft 124 and may be controlled by a single rotary slide valve P', Fig. 12, the passages 117 terminating in passages 127 communicating with an arcuate port 125 in an annular chamber 129 in an inlet housing 131 secured to the framing. The disc type of blade in addition to being air cooled may be further cooled by air or water passing through apertures in closed tubes 153, Fig. 14. The traversing motion of the jets may follow a substantially horizontal vertical or inclined path according to the arrangement of the apparatus.