When drywall panels are installed in a building, and the seams taped, prior to painting the wall surface, there is often applied a spray texture, which is followed by painting. The spray texture will provide a desirable background pattern, and also obscure some of the seams that might appear in the drywall surface.
There are in the prior art various spray texturing tools or devices which utilize pressurized air to spray the texture material onto the wall surface. Some of these use compressed air as the gaseous medium to spray the textured material, with the pressurized air being derived from a remote source that feeds the air through a hose to the tool. There are also tools which are totally handheld, with the pressurized air being produced by manually reciprocating the piston of an air pump that is built into the tool.
When an existing drywall surface is being repaired, quite often a small section of drywall will be removed and another piece of drywall put in its place. The seams of this piece of drywall must then be taped, and (if the surrounding surface is textured) then have a texture surface treatment that would make it match with the surrounding drywall surface. It is, of course, desirable to have the spray pattern on the patch match that of the surrounding surface.
Also, when a rather small "patch" of drywall is to be spray textured, there is the matter of convenience. One approach has been simply to provide the spray texture material in an aerosol can, and the textured material is dispensed directly from the can to be sprayed onto the drywall surface. However, one of the considerations is how this can be accomplished in a manner to provide proper matching of the texture with that which is on the surrounding drywall.
U.S. Pat. No. 5,037,011 (Woods) discloses such an aerosol texture spraying device where the spray texture material is dispensed directly from the nozzle of the aerosol can. In a commercial embodiment of a device such as this, when there is higher pressure in the container, there is a relatively fine spray pattern. For a more coarse pattern (i.e. with larger particle sizes), the can is inverted and the nozzle depressed to dispense a certain amount of the propellant gas for a few seconds. Then the can is turned upright and the spray texture material dispensed at a lower pressure to provide the spray pattern with larger particle sizes.
U.S. Pat. Nos. 5,310,095 and 5,409,148 issued to the present Applicant disclose an apparatus for discharging a spray texture material through a nozzle means having a nozzle discharge opening to dispense this material. There is further provided a first delivery tube means having a first discharge passageway of a first predetermined cross-sectional area. The material discharge apparatus is operated to cause the texture material to be discharged through the tube means. The tube means has been found to maintain the quality of the texture spray pattern for longer spray durations.
If a different texture pattern is desired, a second discharge tube means may be positioned to receive material from the discharge nozzle means, and this second tube means has a second discharge passageway with a second predetermined cross-sectional area different from the first cross-sectional area. A finer spray pattern is obtained by utilizing a tube means with a passageway having a lesser cross-sectional area, and a coarse pattern is obtained by discharging said material through the tube means having a greater cross-sectional area.
One problem with the methods disclosed in the '095 and '148 patterns is that a plurality of parts must be manufactured, shipped, sold, assembled and stored by the end user in order to maintain the capability of the product to create different texture patterns. In particular, three straws must be sold in connection with the aerosol can. While this method is quite inexpensive from a manufacturing point of view, the shipping and sale of the product are somewhat complicated by the need to attach the three straws to the aerosol can. Further, the end user must install the straws into the actuating member of the aerosol can; this is difficult to accomplish without depressing the actuating member and discharging some of the texture material. Also, after the product is used, the user must store the straws such that they are easily available when needed.
In U.S. patent application Ser. No. 08/321,559, it was proposed that the aerosol device include: (a) a container for containing pressurized texture material; (b) a nozzle passageway; (c) a valve assembly for allowing the operator to create a path by which texture material may flow from the container into the nozzle passageway; and (d) an outlet member having a plurality of dispensing passageways formed therein.
The outlet member is arranged adjacent to the dispensing passageway in a manner that allows the user easily to align one of the dispensing passageways with the nozzle passageway. The dispensing passageways are of differing cross-sectional areas. Therefore, by arranging a selected one of dispensing passageways with the nozzle passageway, the texture pattern formed by the texture material on the surface may be varied in a manner similar to that disclosed in the '095 and '148 patents.
While the device disclosed in the '559 application is in one sense easier to use than the device disclosed in the '095 and '148 patents because separate parts need not be manufactured, sold, and stored with the device, the difficulty of including an elongate passageway in the outlet member of the '559 device yields a less satisfactory spray pattern than that provided by the '095 and '148 devices.
In particular, devices employing straws having elongate dispensing passageways yield more consistent spray patterns for longer periods of time than those without elongate dispensing passageways. The need thus exists for an aerosol spray texture device that does not require the manufacture, sale, or storage of separate pieces while at the same time providing a desirable spray pattern.
A problem with the methods disclosed in the '095 and '148 patents and the '559 application is that products embodying these patents contain hydrocarbon gasses that must be disposed of after the container is empty. The hydrocarbon liquids employed as a propellant provide improved spray patterns, however, because this material continues to expand as the texture material leaves the container, thereby atomizing the texture material to form a fine spray rather than a stream. An aerosol device for applying texture material to a surface such as a wall that does not contain hydrocarbon gasses but still yields acceptable spray patterns would be highly desirable.
Accordingly, the need exists for a spray texturing device that is easy to use, inexpensive to manufacture, does not require user assembly, does not require the shipment and storage of a plurality of parts, provides a predictable spray pattern for long periods of time, and does not employ hydrocarbons.