GB743489A - Improvements in or relating to electro metal spraying pistols - Google Patents

Abstract

743,489. Sprayproducers. SCHONBERG, A., KELLINGHUSEN, W., MEYER; A. L. LORENZ-, WITTHOEFFT, F. H., WITTHOEFFT, G., and TROJE, H. BARTELS-, [trading as MEYER, A. O.]. Jan. 27, 1953, No. 2363/53. Class 69 (3). In a metal spraying pistol two continuously advancing metal wires 24, 25 are connected to an electric current source and meet at a point K, Fig. 1, in front of the pistol where they are continuously shortcircuited, their ends melted thereby, and the molten metal is sprayed on to a surface &c. by a compressed air jet flowing through the nozzle head 32. The pistol comprises a housing 10 for wire feed rollers 12-15, the rollers 12, 13 having worm wheels 16, 17 driven by a worm 18 which is driven by a flexible shaft 19. The latter is preferably driven by an electric motor. Rollers 14, 15 are secured to a hinged cover 11 and the pressure between the roller pairs is adjusted by springs 28, 29. The wires are fed into guiding sleeves 30, 31 which support bending rollers 37 and guide rollers 38, 39 within the nozzle head, and the wires pass through guiding nozzles 35, 36. The bending and guide rollers and the associated nozzle for each wire are formed as a unit which is angularly adjustable so that the distance of the wire contact point from the front of the pistol may be varied. Electric supply connectors 43, 44 are secured to the guiding sleeves 30, 31 and current is supplied to the wires mainly through the bending and guide rollers. Wire cleaning chambers may be arranged at the entrance end of the guiding sleeves. Compressed air is delivered to a passage 49 and flows into a chamber 50 and through perforations 51 to the nozzle head. An annular air jet concentric with the main jet may be provided, and for this purpose a tubular member supplied with compressed air may be secured to the front of the nozzle head, said head being secured to the housing by a bayonet joint. In Fig. 11 the wires are fed at an acute angle through a casing 10 so that wire bending is obviated. Feeding rollers 101, 102 are driven via separate worms 105, 106 connected to flexible shafts 107, 108. In Fig. 12 the two wires are fed in straight lines up to the contact point by a common driving shaft 201 and gearing, and compressed atomizing air fed at 202 flows along the wire 25 only. Instead of rollers the current supply to the wires may comprise a link chain 401, Fig. 14, which is recessed to conform to the wire shape and co-operates with toothed chain driving wheels 402. The electric supply to the wires is automatically cut off if the compressed air supply fails and preferably also if the supply to the electric motor driving the feed rollers is interrupted.