Adjustable powder spray gun

Abstract

A powder spray gun which, in the presently preferred embodiment, is particularly adapted for spraying a particular powder spray onto the interior surfaces of containers and other target objects in a confined area. The apparatus includes a rigid tubular support member and a flexible powder transport tube. The rigid support member carries a high voltage cable having a charging electrode at one end. The flexible tube terminates in a discharge nozzle which may be adjustably mounted to the support member adjacent the charging electrode so as to permit variation of the angle at which the powder is released from the nozzle relative to the longitudinal axis of the support member. Intermediate the discharge nozzle and an upstream portion of the powder transport tube which is connected to the support member, the flexible tube is smoothly curved so as to prevent any sharp corners in the transport tube or the nozzle within which powder could collect and interrupt smooth, even discharge of powder from the gun.

What is claimed is: 
     
       1. Apparatus for applying a solid particulate powder coating to the interior surface of a target object, comprising: a mounting block;   a hollow, rigid support member having a longitudinal axis, one end of said support member being mounted to said mounting block, the other, outer end of said support member mounting a powder charging electrode;   a high voltage cable carried .[.with.]. .Iadd.within .Iaddend.said hollow support member for connecting said powder charging electrode to a source of electrical power;   a nozzle including a flow passage having an inlet port at one end and a discharge orifice at the other end, said inlet port receiving solid particulate powder and said discharge orifice ejecting the solid particulate powder in a predetermined pattern from said flow passage;   an adjustment element connected between said nozzle and said outer end of said support member for positioning said discharge orifice of said nozzle proximate said powder charging electrode to electrostatically charge solid particulate powder ejected from said discharge orifice;   means connected to said adjustment element for adjusting the .[∠]. .Iadd.direction .Iaddend.of said nozzle flow passage in said nozzle relative to said longitudinal axis of said support member;   a flexible tube for transmitting solid particulate powder, said flexible tube having an upstream portion fixedly connected to said .[.support memberΘ .Iadd.mounting block .Iaddend.and a discharge end fixedly connected to said inlet port of said nozzle flow passage;   said flexible tube being disposed in a plane oriented generally perpendicularly to said discharge orifice so as to direct the solid particulate powder .[.substantially vertically upwardly.]. through said nozzle flow passage;   said flexible tube being smoothly curved between said discharge end and said upstream portion so as to prevent powder from becoming entrapped in sharply angled corners of a powder flow path between said upstream portion of said flexible tube and said discharge orifice of said nozzle.   
     
     
       2. The apparatus of claim 1 wherein the upstream portion of said flexible tube has a section which extends generally parallel to the longitudinal axis of said support member. 
     
     
       3. The apparatus of claim 1 in which said nozzle is adapted to be adjusted to dispose said flow passage of said nozzle at acute or obtuse angles relative to said longitudinal axis of said support member. 
     
     
       4. The apparatus of claim 1 wherein: said adjustment element comprises an elongate member formed with a slot at each end;   said means connected to said adjustment element comprises a pair of set screws, a threaded bore being formed in each of said nozzle and said support member;   said elongate member being positioned so that each of said slots therein overlies said threaded bore in one of said nozzle and said support member, said elongate member being releasably connected to said nozzle and said support member by inserting said set screws through said slots and tightening them within said threaded bores, said set screws being adapted to be loosened to permit movement of said nozzle so as to dispose said flow passage thereof at varying angles relative to the longitudinal axis of said support member.   
     
     
       5. The apparatus of claim 1 further including a mounting assembly comprising a frame member, a rod movably mounted to said frame member, and said mounting block movable along said rod, said support member being mounted to said mounting block so that said longitudinal axis of said support member is generally perpendicular to said rod, said mounting assembly being movable laterally and rotatably relative to .Iadd.an axis substantially parallel to .Iaddend.the longitudinal axis of said support member. 
     
     
       6. The apparatus of claim 1 in which said discharge orifice of said nozzle is formed in a generally rectangular shape for spraying said powder spray onto said target object.