Patent Grant
8273417
As authorized by 35 U.S.C. §119, this application claims priority to and hereby incorporates by reference Canadian Application Serial No. 2,641,508, titled ANNULAR AIR CURTAIN FOR ROBOTIC PAINT SYSTEMS, filed on Oct. 22, 2008.
The present invention is directed to a system and method for spraying a coating, such as paint. More particularly, the present invention is directed to a robotic spray coating assembly and method for spraying a coating.
Robotic spray coating systems are widely used on manufacturing lines. In some cases, robotic spray coating systems may coat objects with paint, although other materials may also be sprayed. While robotic spray coating systems are useful for providing superior finishes, such systems can often produce an accumulation of coating material due to “overspray”. This occurs when trace coating material particles leaving a coating spray do not set on a target work piece and instead drift away and deposit on surrounding structures, including expensive robotic components. This requires time consuming regular cleaning procedures and, in some cases, may risk reduced coating quality.
Consequently, it can be understood that it would be desirable to reduce overspray in robotic spray coating applications. The present invention is directed to a robotic spray coating assembly and method for spraying a coating that reduces overspray, as well as a vehicle spray painting system utilizing such a robotic spray coating assembly.
The present invention is directed to an overspray-reducing robotic spray coating assembly and its associated method of use. The present invention also contemplates a vehicle spray painting system and a vehicle painted therewith. A coating applied by an assembly, system or method of the present invention may be paint, or may be another of various sprayable materials that would be familiar to one skilled in the art.
A robotic spray coating assembly of the present invention generally includes a robotic arm having a remote end region and a coating head mounted on the remote end region. The coating head may have a housing that defines a coating delivery region. The assembly my have at least one first orifice located in the coating delivery region, with a coating material supply connected to the first orifice. One or more second orifices may be positioned in a pattern beyond the periphery of the coating delivery region. A fluid supply may be connected to the one or more second orifices to form a fluid curtain that encircles the coating delivery region to minimize overspray emerging therefrom. The fluid used to form the fluid curtain may be air or another fluid that would be familiar to one skilled in the art.
In certain embodiments of the present invention, the coating head housing may include an outer peripheral surface with a ring portion being positioned on the outer peripheral surface and the one or more second orifices located in the ring portion. In these embodiments, the ring portion may have one or more second orifices located on a path along the outer surface.
The ring portion of certain embodiments of the present invention may include an annular chamber, where each of the second orifices is in communication with the annular chamber. In certain embodiments, the ring portion has an inner surface with a first inner diameter, with the outer peripheral surface having a second outer diameter. Embodiments of the present invention may have one or more second orifices that are integrally formed with the remote end portion.
The present invention also includes methods of minimizing overspray by providing a robotic spray assembly as described above and emerging from a robotic spray coating assembly. Such a method preferably includes providing a robotic spray coating assembly with a coating head defining a coating delivery region, the coating delivery region including at least one coating delivery orifice; providing one or more fluid curtain orifices positioned in a fluid curtain pattern at or beyond the periphery of the coating delivery region; directing the coating delivery region at a work piece; delivering a supply of coating material to the coating orifice to produce a coating spray pattern beyond the coating delivery region so as to form a coating on the work piece; and delivering a fluid to the fluid curtain orifice(s) to form a fluid curtain to minimize coating overspray emerging from the coating delivery region. The coating material applied by a method of the present invention may be paint, or may be another of various sprayable materials that would be familiar to one skilled in the art. The fluid used to form the fluid curtain according to a method of the present invention may be air, or may be another fluid that would be familiar to one skilled in the art.
The present invention is also directed specifically to a vehicle painting system. In a vehicle painting system of the present invention, a robot coating assembly is associated with a coating line provided to carry a plurality of vehicle bodies to be painted along a vehicle painting path. A robotic arm is preferably located adjacent the vehicle painting path. The robotic spray painting assembly of the above-described method of minimizing overspray is deployed on the robotic arm. The present invention also includes a method of painting a vehicle body using such a vehicle painting system.
The present invention further contemplates a work piece comprising a coating formed by the above-described method. The work piece may be a vehicle body. The coating applied to the work piece may be paint or another of various sprayable materials that would be familiar to one skilled in the art.
In addition to the features mentioned above, other aspects of the present invention will be readily apparent from the following descriptions of the drawings and exemplary embodiments, wherein like reference numerals across the several views refer to identical or equivalent features, and wherein:
It should be understood that the present invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the associated drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings. Furthermore, and as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention. However, other alternative mechanical configurations are possible which are considered to be within the teachings of the instant disclosure. Furthermore, unless otherwise indicated, the term “or” is to be considered inclusive.
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In this particular method, a robotic arm 12, equipped with the above-described coating head 16 and ring portion 30, is located adjacent a vehicle path 21a. The robotic arm 12 and robotic spray coating assembly 10 are then used to paint the vehicle body 21. More specifically, the robotic arm 12 is manipulated to direct the coating delivery region 20 of the robotic spray coating assembly 10 toward the vehicle body 21, so that a paint supply may be activated to form a coating spray pattern beyond the coating delivery region to apply a paint coating on the vehicle body. During the painting operation, a supply of paint is delivered to the coating head 16, and a supply of fluid is delivered to fluid curtain orifices located in the ring portion 30. The fluid is delivered to the fluid curtain orifices at a sufficient flow rate so as to be emitted therefrom to form the fluid curtain described above. This fluid curtain is operative to minimize paint overspray emerging from the coating delivery region 20.
To operate the particular robotic spray coating assembly 10, the ring portion 30 is installed on the housing 18 with the fluid supply line 28 inserted in, or in fluid communication with, the passage 34a. The fluid supply line 18 may then be pressurized with fluid F that fills the annular chamber 32, thereby causing the fluid to exit the second orifices and to establish the fluid curtain A. Next, the coating supply 24 is activated to form a spray or fluid stream of coating P (see
It should be noted that the sectional view of
In addition to the foregoing, it may be desirable to provide a robust fluid supply, which may include air or a mixture of air and other liquids such as water. The pressure associated with such a fluid supply may range from about 30 pounds per square inch (psi) to about 80 psi. It should be noted, however, that excessive fluid supply pressures may be ineffective in some cases, and may actually interfere with the spray or coating stream of fluid P.
Thus, as shown and described herein, embodiments of the present invention are useful to minimize coating overspray on a robot gun and spray nozzle or cap, by way of an air ring. The ring may be configured to slide over the base of the gun and to be held thereon with a number (e.g., three) of set screws. One or more air lines (e.g., two) may be used to supply air around the ring. Such air lines may have various diameters, such as a diameter of about 6 mm for example. According to this construction, fluid (e.g., air) enters a chamber within the air ring, from which it is subsequently dispersed through pilot holes. The pilot holes may be of various diameter, such as for example, approximately 1 mm in diameter or larger. The diameter of the pilot holes may depend on the requirements of the resulting air curtain. In other embodiments, the pilot holes may be replaced by one or more elongate slots or the like.
In operation, the air travels along the shaft of the gun, which in turn forces the overspray back into the coating path and off of the gun. While the ring portion and its structure to provide the fluid curtain is particularly useful to retrofit existing coating assemblies, the second orifices and the annular chamber, or functional equivalents of the second orifices and the annular chamber, may be integrated into the housing, as desired, to provide a pattern beyond the periphery of the coating delivery region so as to form the air curtain as described. The ring portion may be provided in a kit for retrofitting existing coating assemblies or may be included in the assembly of coating assemblies. While such a ring portion is especially well-suited to use on a robotic spray coating assembly, it may also be applicable to manual coating assemblies in some cases. Further, while the second orifices have been shown and described as forming a fluid curtain that surrounds the entire coating delivery region, there may be applications in which it may be useful to produce a fluid curtain along only a portion of the boundary of the coating delivery region. Thus, it is not required in all cases that the fluid curtain encircle the entire delivery region.
While certain embodiments of the present invention are described in detail above, the scope of the invention is not to be considered limited by such disclosure, and modifications are possible without departing from the spirit of the invention as evidenced by the following claims. The scope of said claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2641508 | Oct 2008 | CA | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20100098871 A1 | Apr 2010 | US |
