GB1117365A - Flame spray gun - Google Patents

Abstract

1,117,365. Spray, producers. METCO Inc. 11 Oct., 1965 [11 Jan., 1965], No. 43064/65. Heading B2F. [Also in Division F2] A wire type flame spray gun has a wire feed drive train including a wire feed roller, the speed of which is controlled by a speed governor, and torque-sensing means which directly senses changes in the torque required to drive the feed roller independent of a change in the speed of the drive and which varies the power output of the drive transmitted through the drive train to increase the power output as the torque increases and to decrease it as the torque decreases. Feed rollers 8 and 9 are driven through a gear train comprising worm gear 17 Fig. 2 on shaft 16, meshing with worm 18 on shaft 19 Fig. 4, shaft 19 being rotatable by worm gear 20 meshing with worm 21 connected to turbine shaft 22 bearing turbine rotor 23. Brake disc 24 is axially displaceable along shaft 22 and a centrifugal power absorbtion speed governor comprising spring 25 and flyweights 26 is connected to the turbine rotor to maintain a constant speed by operation of disc 24 against annular brake shoe 30. Shaft 22 mounted for limited axial displacement against disc spring 42 constitutes the torque sensing means. With an increase in the drag on feed rollers 8 and 9 (e.g. caused by a greater drag on wire 6) there is a greater torque in worm 21 and the axial component of this torque moves shaft 22 towards and against the force of spring disc 42, thus decreasing the pressure of brake disc 24 on shoe 30 and increasing the power available in the drive train. A decrease in the torque in the drive train will have the reverse effect. In alternative embodiments the drive train may include mating bevel gears (Fig. 7) or mating couplings carrying serrated teeth (Fig. 6) which components move apart against a spring force as the torque increases, thus varying the braking force. Similar torque sensing means may be used in conjunction with other power regulating devices e.g. movement of shaft 22 may vary an electrical resistance in an electrically powered drive train. Wire 6 is fed from rollers 8 and 9 into a pasage extending through gas head 3 to nozzle 4 which has a central wire feed passage and is supplied with a ring of burner jets fed with a combustible gas mixture. A blast gas e.g. air, is fed through valve (5) and air cap (4 Fig. 1 not shown), to impinge on the heat-softened tip of the wire, continuously atomising it and propelling the atomised particles as a spray away from the gun. The gun may be used for spraying metals and refractory oxides.