Coating apparatus – Solid applicator contacting work – Pads or absorbent or porous applicators
Reexamination Certificate
1998-07-31
2001-05-08
Edwards, Laura (Department: 1734)
Coating apparatus
Solid applicator contacting work
Pads or absorbent or porous applicators
C118S266000, C118S268000, C118S255000
Reexamination Certificate
active
06228168
ABSTRACT:
TECHNICAL FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for applying a liquid to a substrate and, more particularly, to an automated method and apparatus for applying one or more liquids, including for example a primer coating or a treatment liquid, to a glass panel, such as a window assembly.
The recent trend in vehicles is to produce an aerodynamically shaped vehicle with larger windows to improve visibility. In order to reduce the aerodynamic drag and enhance the overall appearance, window assemblies are more recently mounted to the vehicle body by an adhesive, often in combination with one or more fasteners which are mounted to an inner surface of the window panel or are embedded in a gasket which has been previously extruded or molded on to the window panel after priming of the substrate surface. It has been found that the priming of the substrate surface improves the adhesion of the gasket to the substrate. The adhesive is applied to the surface of the panel or the gasket, for example by extrusion. To install, the window assembly is then pressed against the mounting flange or decking of the vehicle body to which the adhesive adheres after curing. In other windows, the securement of the window panel to the vehicle is achieved by a fastening system. In some fastening systems, the fastener is adhered directly to the surface of the window by an adhesive. Before applying such adhesives, the window panel is preferably treated with a treatment liquid, such as an acid solution or cleaning solution, to prepare the glass panel and improve the adhesion of the adhesive to the glass panel. In many windows, therefore, the adhesive often provides the primary attachment of the panel to the vehicle.
However, window assemblies often include compound curvatures, which make it hard to automate the application of the gasket primer or treatment liquid. In preferred forms, the primer or treatment liquid is directly applied to the window substrate rather than sprayed or wiped on in order to achieve a more uniform coverage and thickness. As a result of the compound curvatures and the irregularities in the surface topology of window panels, direct application of a primer or treatment liquid to a window assembly has been more typically accomplished manually with the use of an applicator.
Conventional applicators include a tip, for example a pad, including a felt pad, and a reservoir which holds a supply of the primer solution or treatment liquid. However, when applying a liquid that dries when exposed to air, such as most conventional primers, the pads of the applicators must be replaced frequently. For example, primers dry relatively quickly in ambient conditions and tend to harden the pad and clog up the applicator. As a result, applicator tips or pads require frequent replacement, and the applicator reservoir must be cleaned and flushed before refilling.
As described above, heretofore, manual application of the primer has been preferred due to the compound curvatures and irregularities in the surface topology of the window assembly substrate and more consistent results due to varying conditions of the substrate (i.e. frit, contamination, temperature, or the like). Furthermore, it has been found that in order to achieve optimal results, the liquid is preferably applied with a constant pressure so that a uniform coating can be achieved. Heretofore, this constant pressure has been easier to achieve with manual application. However, manual application may result in inaccurate primer or treatment liquid placement and the coating thickness may vary with each worker. Moreover, conventional primer systems are open systems which result in prolonged exposure of the primer to contaminants. Given the reactive nature of primer solutions, these open systems cause the primer solution to prematurely cure. Therefore, these open primer systems are wasteful and require frequent cleaning and or replacement of the applicators.
Consequently, there is a need for a liquid application system which will produce the same advantages of a manually applied coating system, including a substrate surface and substrate condition variation sensitive system, but will require less material usage and, consequently, produce less waste than a manual application process. Furthermore, there is a need for a liquid application system that will provide a longer life for the applicator tip. In addition, there is a need for a primer application system which can provide a highly accurate primer or treatment liquid placement and produce a repeatable coating thickness. Moreover, there is a need for a closed primer system which will reduce waste and increase the life of the applicator and further reduce contamination of the treatment liquid or primer solution.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for applying a liquid, such as a treatment liquid or primer, to a substrate with an applicator assembly, which is responsive to variations in the characteristics and surface topology of the substrate. Preferably, the primer applicator assembly can apply the liquid to the substrate with a constant pressure so that the applied liquid will have a uniform shape and thickness. Furthermore, when used in a primer application process the present invention provides a liquid applicator system which prevents the premature hardening of the primer solution in the applicator and, consequently, increases the life of the applicator. Moreover, the primer applicator assembly permits automation of the liquid application process and, therefore, can provide a highly accurate coating placement and produce a repeatable application path and coating thickness. In addition, the applicator system provides a closed system that is particularly suitable for applying primers which eliminates or substantially reduces the contamination of the liquid and the amount of volatiles which escape from conventional primer solutions.
In one form, an applicator assembly for use in an automated liquid application system for applying a liquid to a substrate includes a base, which is adapted to be gripped by a holding member, and a liquid applicator. The applicator is moveably mounted on the base and is adapted to receive a supply of liquid and is positionable on the substrate by the holding member for applying the liquid to the substrate. The liquid applicator moves on the base to follow the contour of the substrate thereby applying constant pressure to the substrate during a liquid application process.
In one aspect, the base includes a pin, with the liquid applicator being slidably mounted on the base by the pin. Preferably, the liquid applicator is mounted on the pin by an adapter, which includes a transverse supply passage for receiving the liquid. The applicator is mounted to the adapter and is communication with the transverse supply passage for receiving the liquid. In further aspects, the adapter includes a liquid applicator fitting mounted thereon, with the applicator fitting including the liquid applicator. In another aspect, the applicator includes a mounting portion, a flange portion, and an applicator tip coupled to the flange portion. Preferably, the applicator fitting extends into the mounting portion of the liquid applicator and is coupled thereto by a friction fit so that the applicator is removably mounted to the applicator fitting. In preferred form, either the applicator fitting or the mounting portion includes an annular seal to provide a fluid type connection between the applicator fitting and the liquid applicator and, optionally, to provide the friction fit. In further aspects, the applicator tip preferably comprises a pad, for example a felt pad, which absorbs the liquid for directly applying the liquid onto the substrate.
In yet further aspects, the base includes a pair of flanges, which provide stops and limit the movement of the adapter between a first position and a second position along the pin. Optionally, the applicator assembly may further include a biasing member which is m
Donnelly Corporation
Edwards Laura
Van Dyke Gardner, Linn & Burkhart, LLP
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