Paint gun incorporating a laser device

Abstract: A spray gun (10) for applying a liquid spray coating, such as paint, to a surface incorporates a light source system for gauging the position of the spray gun relative to a worksurface in order to optimize application of the coating to the surface. The light source (38) is preferably in the form of a laser which emits a pair of light beams (50,52) toward the worksurface. The pair of light beams converge toward each other in a direction toward the surface, and the position of the beams on the surface is used by the operator to judge the distance of the spray gun from the surface. An adjustment mechanism (54) is interconnected with one of the light beam sources, so as to adjust the point of convergence of the light beams. A closable door (60) is associated with the spray gun housing at one of the light beam emitting locations, to selectively prevent emission of one of the light beams from the spray gun, such that a single light beam (50) is emitted from the spray gun for use as a reference for spot application of the coating to the surface.

Description: BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to spray painting systems, and more particularly to a spray painting optimisation system that can reduce paint waste and improve operator efficiency in application of paint or other coating to a surface. Spray paint guns spray paint from a nozzle with compressed air onto a surface being painted. In order to optimise the quality of the finish of the painted surface, it is important to maintain the spray gun at an optimal position relative to the surface. Most importantly, the distance of the nozzle from the surface and the angle of the spray gun relative to the surface must be carefully controlled in order to apply the paint to the surface in a manner which minimizes paint waste and maximises efficiently in applying the paint to the surface while maintaining the appropriate thickness of paint applied. U.S. Patent No. 5,598,972, assigned to the same assignee as the present application, discloses an optical spray paint optimisation system in which a laser device is mounted alongside a spray gun. The laser device emits a split beam which converges toward the surface. The operator positions the spray gun such that the light beams converge into a single point of light on the surface, for providing a visual indication as to whether the nozzle is a predetermined distance from the surface. The point of convergence of the light beams can be adjusted to provide the optimal distance of the nozzle from the surface to accommodate for varying operator conditions and paint characteristics. US Patent No. 4,934,086 discloses a firearm having a laser diode mounted therewithin, and a collimating lens arranged for collimating a beam of light from said laser diode, the lens being mounted to direct said beam forward of a recoil spring guide on the axis of said spring guide, so that the beam is parallel with the barrel of the firearm. U.S. Patent 5 757 498 issued May 26, 1998 also owned by the same assignee as the present application, discloses an optical feedback system utilizing a laser device mounted alongside a spray gun in which light from the laser is reflected from the surface and received by one or more optical sensors or input devices interconnected with a processor. The optical input devices provide input signals to the processor which are used to provide a real-time indication to the operator as to the position of the nozzle, so as to enable the operator to place the nozzle and apply the paint in a manner which minimizes waste and maximises efficiency in applying the paint to the surface. The optical input devices can also supply raw data to a processor or computer after the painting operation, to analyze overall efficiency and compliance with standards or other operating parameters. As set forth above, a light beam, such as a beam emitted by a laser, can be effectively used in combination with a paint spray system in order to optimise application of the paint to the surface. Past efforts have involved mounting a laser device to the spray gun in somewhat of a retrofit manner, typically at a location adjacent the nozzle portion of the spray gun. This mounting of the laser device moves the overall centre of gravity of the assembly when compared to that of a spray gun without a laser device, and to which an operator is accustomed. The operator must compensate by adjusting his grip on the gun and the motions used to move the gun when applying the paint to the surface. It is an object of the present invention to incorporate a light-emitting device, such as a laser device, into a spray gun without any significant effect on the overall centre of gravity of the spray gun. It is a further object of the invention to incorporate a laser-type light emitting device into the housing of the spray gun without significantly altering the overall configuration of the spray gun. Still another object of the invention is to incorporate a laser-type light emitting device into a spray gun and to emit a pair of convergent light beams from the spray gun toward the surface to provide a reference in positioning the spray gun relative to the surface. In accordance with the present invention, there is provided a hand-held spray gun for applying a coating to a surface, comprising: a housing defining a forward end, a rearward end and an interior, wherein the housing includes a handle located toward its rearward end; a nozzle mounted to the housing toward its forward end for discharging the coating therefrom; and a light generating device; characterised in that the light generating device is disposed within the interior of the housing toward the rearward end of the housing, in that the light generating device includes a pair of light-transmissive members extending forwardly therefrom within the interior of the housing, in that the housing includes a pair of openings spaced apart from each other at respective different parts of the housing, and in that each light transmissive member terminates at an end located adjacent one of the openings so as to communicate a pair of non-parallel light beams from the light-transmissive members forwardly from the interior of the housing to the exterior of the housing towards the surface, and further including a shut-off mechanism for selectively preventing emission of one of the light beams such that a single beam is emitted toward the surface from the light generating device. Preferably the housing defines a box-like portion adjacent its rearward end, wherein the light generating device is disposed within the box-like portion and wherein the handle is interconnected with and extends downwardly from the box-like portion. Desirably a first one of the openings is located toward the housing forward end and wherein a second one of the openings is located rearwardly of the housing forward end. Conveniently the first one of the openings is located so as to emit a light beam from a location immediately adjacent the nozzle. Advantageously the pair of openings are arranged so as to emit a pair of light beams which converge toward each other in a direction toward the surface from the spray gun. More preferably the spray gun further comprises an adjustment mechanism associated with one of the openings for adjusting the angle at which the light beams converge. More conveniently the single light beam is emitted in a direction substantially parallel to the direction in which the coating is discharged from the nozzle to provide a reference for spraying the coating onto the surface. Most conveniently the opening from which the single light beam is emitted is located immediately adjacent the nozzle. Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate the best mode presently contemplated of carrying out the invention. In the drawings: Fig. 1 is a side elevation view of a paint spray gun incorporating a light emitting device in accordance with the present invention; Fig. 2 is a front elevation view of the paint spray gun of Fig. 1; Fig. 3 is a partial section view taken on line 3-3 of Fig. 1; and Fig. 4 is a partial side elevation view showing the door member in a closed position for preventing emission of one of the light beams. DETAILED DESCRIPTION OF THE INVENTION Fig. 1 illustrates a spray gun 10 constructed according to the invention. Spray gun 10 uses compressed air to spray a coating, such as paint, from a nozzle 12 onto a surface or object being coated (not shown). Generally, spray gun 10 includes a housing defining a spray head section 14 extending forwardly from a box-like body section 16. A handle 18, in the form of a hand grip, extends downwardly from body section 16. Spray head section 14, body section 16 and handle 18 define an interior of the housing of spray gun 10. In a manner as is known, a paint supply fitting 20 is mounted to the lower end of handle 18 via a bracket, for supplying paint from a paint supply (not shown) to spray head section 14 through a tube 22 and a fitting 24. A compressed air inlet fitting 26 is also interconnected with the lower end of handle 18 via a bracket, for supplying compressed air to body section 16. A trigger 28 is pivotally mounted to body section 16 via a pin 30, and is operable to control the position of a valve plunger 32 for selectively discharging pressurized air from body section 16 into spray head section 14 for mixing with paint from supply tube 22, with the mixture then being discharged through nozzle 12 onto a surface to be coated. Body section 16 includes an upstanding hook 34, which enables spray gun 10 to be hung for storage when not in use. Control levers, such as shown at 36, are mounted to the rearward end of body section 16 for turning spray gun 10 on and off and for controlling the flow of pressurized air through body section 16 when trigger 28 is depressed. In accordance with the present invention, a light generating source 38 is incorporated into housing body section 16. Light generating source 38 may be any satisfactory device for generating an intense beam of light, and in a preferred embodiment may be a class II diode laser. A control area 39 is provided at the rearward end of housing body section 16 for providing on/off and intensity control for light generating source 38 and for controlling other operating conditions and functions, as desired. A pair of fiber optic cables 40, 42 are interconnected with and extend forwardly from light generating source 38 within the interior of housing body section 16. Cable 40 extends forwardly from housing body section 16 through spray head section 14, and terminates at the forward end of spray head section 14. An opening 44 (Fig. 2) is formed in nozzle 12 so as to engage the beam of light emitting by the end of fiber optic cable 40 to pass through nozzle 12 and forwardly toward the surface beam painted. Similarly, fiber optic cable 42 extends upwardly from housing body section 16 through a passage formed in upstanding hook 34. A box 46 is provided at the upper end of hook 34, and fiber optic cable 42 extends into box 46. An opening in the form of a slot 48 is formed in the forward end of box 46 so as to enable the beam of light emitted by fiber optic cable 42 to be emitted from box 46 forwardly toward the surface being painted. In a known manner, laser source 38 generates a single beam of light which is split in accordance with conventional technology, and the split beams are emitted from laser source 38 to fiber optic cables 40, 42. As shown in Fig. 1, fiber optic cable 40 and opening 42 are arranged such that the beam of light emitted by fiber optic cable 40, shown at 50, is emitted from spray gun 10 in a direction parallel to the direction in which the coating is discharged from nozzle 12 toward the surface. In the illustrated embodiment, the direction of discharge of light beam 50 relative to spray gun 10 is fixed. Referring to Figs. 1 and 3, fiber optic cable 42 and slot 48 are constructed and arranged such that the beam of light, shown at 52, emitted by fiber optic cable 42 is oriented at an angle relative to light beam 50, such that light beams 50, 52 converge toward the surface being painted. Light beams 50, 52 each form a spot of light on the surface, and the operator utilizes the distance between the light spots to judge the distance of spray gun 10 and its nozzle 12 relative to the surface. As set forth in U.S. Patent No. 5,598,972, the angle between light beams 50 and 52 is such that when the spots of light on the surface from beams 50, 52 converge into a single spot, the distance of nozzle 12 relative to the surface is optimal for applying paint to the surface with minimal waste. Referring to Fig. 3, an adjustment knob 54 is rotatably mounted to one side wall of box 46, and a shaft 56 extends from knob 54 into the interior of box 46. A collar 58 is mounted to the end of shaft 56, and fiber optic cable 42 extends through collar 58. The operator can rotate knob 54 to turn shaft 56 and collar 58, which in turn functions to adjust the angle at which light beam 52 is emitted from box 46. Slot 48 is constructed so as to enable emission of light beam 52 throughout its range of angular positions relative to box 46. Calibrations are provided on the exterior side wall of box 46 to which knob 54 is mounted, so as to enable a user to gauge the adjustment of the angle of light beam 52 relative to spray gun 10. In this manner, the user can adjust the angle of discharge of light beam 52 according to operating conditions and paint characteristics, so that the distance of spray gun 10 from the surface at which light beams 50, 52 converge on the surface can be adjusted according to such conditions. As shown in Figs 1 and 4, a movable door 60 is mounted to the upper wall of box 46 via a hinge structure 62. Door 60 is movable between an open position as shown in Fig. 1 and a closed position as shown in Fig. 4. In a preferred form, a retainer structure is provided between door 60 and the upper wall of box 46 for maintaining door 60 in its open position, and is also provided between door 60 and the front wall of box 46 for maintaining door 60 in its closed position. When door 60 is in its open position, light beam 52 is emitted from slot 48, as set forth above. When door 60 is in its closed position of Fig. 4, door 60 prevents light beam 52 from being emitted from slot 48, such that only light beam 50 is emitted from spray gun 10 toward the surface. In this manner, light beam 50 functions to provide a reference on the surface for the user, which is useful when spot-applying paint in a desired location on the surface. Since light beam 50 is emitted in a direction parallel to the direction of spray from paint gun 10, the spot on the surface from light beam 50 provides a reliable reference to the user as to the location on the surface at which paint from nozzle 12 will be applied. It is understood that light generating source 38 could be any source of light and is not limited to a laser-type source. In addition, the light source and spray gun could be constructed such that light beams 50 and 52 emanate from other spaced apart locations on spray gun 10 toward the surface, and are not limited to the illustrated locations. For example, additional protrusion could be formed in other locations on spray gun 10 for receiving the end of a fiber optic cable and discharging a light beam therefrom toward the surface. It can thus be appreciated that the invention incorporates a light source system into a spray gun without affecting the general overall configuration of the spray gun and without affecting the center of gravity of the spray gun. The spray gun can thus be used by an operator without modifying existing techniques, and enables the operator to increase his or her efficiency in application of paint by accurately judging the distance of the spray gun relative to the surface. Various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.

Claims: A hand-held spray gun (10) for applying a coating to a surface, comprising: a housing defining a forward end, a rearward end and an interior, wherein the housing includes a handle (18) located toward its rearward end; a nozzle (12) mounted to the housing toward its forward end for discharging the coating therefrom; and a light generating device (38); characterised in that the light generating device (38) is disposed within the interior of the housing toward the rearward end of the housing, in that the light generating device (38) includes a pair of light-transmissive members (40, 42) extending forwardly therefrom within the interior of the housing, in that the housing includes a pair of openings (44, 48) spaced apart from each other at respective different parts of the housing, and in that each light transmissive member terminates at an end located adjacent one of the openings (44, 48) so as to communicate a pair of non-parallel light beams (50, 52) from the light-transmissive members forwardly from the interior of the housing to the exterior of the housing towards the surface, and further including a shut-off mechanism (60) for selectively preventing emission of one (52) of the light beams such that a single light beam (50) is emitted toward the surface from the light generating device. The spray gun of Claim 1, wherein the housing defines a box-like portion (16) adjacent its rearward end, wherein the light generating device (38) is disposed within the box-like portion and wherein the handle (18) is interconnected with and extends downwardly from the box-like portion. The spray gun of Claim 1, wherein a first one (44) of the openings is located toward the housing forward end and wherein a second one (48) of the openings is located rearwardly of the housing forward end. The spray gun of Claim 3, wherein the first one (44) of the openings is located so as to emit a light beam (50) from a location immediately adjacent the nozzle. The spray gun of Claim 3, wherein the pair of openings (44, 48) are arranged so as to emit a pair of light beams (50, 52) which converge toward each other in a direction toward the surface from the spray gun. The spray gun of Claim 5, further comprising an adjustment mechanism (54, 56, 58) associated with one (48) of the openings for adjusting the angle at which the light beams converge. The spray gun of Claim 1, wherein the single light beam (50) is emitted in a direction substantially parallel to the direction in which the coating is discharged from the nozzle to provide a reference for spraying the coating onto the surface. The spray gun of Claim 7, wherein the opening (44) from which the single light beam is emitted is located immediately adjacent the nozzle (12).

Inventors: BADAKHSHAN ALIREZA, BAUER RICKY JAY, KLEIN RICHARD J II, SEVEY DOUGLAS L, BADAKHSHAN, ALIREZA, BAUER, RICKY JAY, KLEIN, RICHARD J., II, SEVEY, DOUGLAS L., Bauer, Ricky Jay, Iowa Waste Reduction Center
Applicants: UNIV NORTHERN IOWA FOUNDATION, THE UNIVERSITY OF NORTHERN IOWA FOUNDATION
Application year: 1998
Main classification: B05B12
IPC codes: G01S17, B05B15, G01B11, B05B5, B05B1, B05B12