Dispensing – Automatic control – Of dispensers with fluid pressure discharge assistance
Reexamination Certificate
2002-10-08
2004-03-30
Mancene, Gene (Department: 3754)
Dispensing
Automatic control
Of dispensers with fluid pressure discharge assistance
C222S399000, C417S900000
Reexamination Certificate
active
06712238
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to drywall taping and texture systems, and, in particular embodiments, to a drywall taping and texture system using an automatic pneumatic bladder pump with a flip/flop logic mechanism, that may be controlled remotely by an operator.
BACKGROUND OF THE INVENTION
Traditionally, in gypsum wallboard or “drywall” panel installation, sheets of drywall are nailed or screwed in place. Seams between the drywall sheets must be taped over, and the nail or screw heads must be coated with paper tape and mastic material to form a continuous wall surface. Tape and mastic material must also be applied to inside corners to form a complete wall system. The task of applying drywall tape and mastic drywall mud is generally laborious, tedious, and messy. Although inventions have made the task easier, improvement is still needed. One currently available drywall taping tool is the pedestrian mud pan and drywall knife.
With a mud pan and drywall knife, a workman manually applies drywall tape and mud. First, the workman removes a scoop of mud from a bulk container in a mud supply area and places it in the mud pan. This action is repeated until the pan is full. The workman then walks from the mud supply area to the seam that he wishes to tape. The workman then scoops a quantity of mud onto the knife, turns the knife blade towards the wall, and with a series of wiping motions, coats the seam with mud more or less uniformly. After precutting the tape, the workman lays paper tape over the seam and presses it into the mud to achieve tape attachment. He then glides the knife over the tape, forcing mud and air out from behind the tape, and begins to smooth the surface. A first coat of mud is applied to the drywall tape either at the time that the tape is applied or later, depending on the workman's technique.
After a period of drying, another coat of mud is applied to the tape and dressed with a drywall knife, thus covering the seam with a wider coat of mud. The same steps of walking to the mud supply area, scooping out mud until the pan is full, and then walking back to the work area are repeated.
After a second period of drying, most inexperienced workmen sand the seams before applying a final coat of mud. The final coat of mud requires further walking between the mud supply and the work areas and further scooping and filling of the mud pan as before.
Complicating the situation are inside corner seams. Most occasional drywall workmen find inside corner seams the hardest and most time consuming to tape and coat of any seam. There are special knives that have a ninety degree bend to help dress these difficult seams.
To overcome the drawbacks of pedestrian drywall tape application and finishing tools such as the mud pan and drywall knife, a professional “automatic” drywall taping system has been developed by Ames Tool Company (Ames), for example, that includes a manual, lever action, fluid mud pump that fills assorted mud applicator tools from a 5 gallon bucket filled with slightly thinned drywall mud. A hand lever on the manual pump is pumped up and down to transfer drywall mud out of the bucket directly into a mud applicator tool. The mud is squirted into a slot in some tools and into other tools through a special fitting.
However, this system still requires walking between the mud supply station and the current work areas, thus wasting time and energy. Only about ninety feet of tape can be applied with the Ames taper tool before a mud refilling is required, while each roll of paper tape is about 500 feet. Only about three to four vertical seams, where each seam is about eight feet long, can be filled with the Ames box tools before more mud is required. Thus, a day's work may require hundreds of trips for mud refills between the mud supply and work areas with the Ames drywall taping system.
Additionally, each of the tools in the Ames system takes some toll upon the user's energy. The Ames taper tool is powered by the user forcing a wheel to turn as it contacts the wall at the end of the tool. The Ames box tool requires the operator to forcefully wipe a heavy box of mud held out on an extended handle. Each of the Ames tools mechanically disgorges drywall mud as the result of strenuous human labor. Many tasks in drywall taping with Ames type systems are thus prone to cause repetitive stress injury.
Furthermore, Ames tools require both a reservoir that holds one shot of mud and a mechanical device to manually exude the shot of mud out of the tool and onto a drywall surface. The Ames system is expensive, heavy, and manually actuated. Ames-type tools are now manufactured by several companies using similar designs that are based upon many complicated and varied machined metal parts and are thus expensive to manufacture. Those tool designs do not lend themselves to mass production of most of the parts (e.g., in plastic) for the “do it yourself” market. There is also a learning curve with Ames-type tools due to the skill required to properly operate them. In addition, there is extensive tool cleaning required after each use to ensure proper operation, and tool failures are common in the Ames system due to dried mud and mechanical failures.
The stator tube pump is well known to the drywall industry, particularly with commercial drywall texture sprayers. This type of pump has a hollow threaded internal rubber sleeve encompassing a softly threaded extended rod. As the rod is turned, fluid drywall material is forced to exit the pump under pressure into a material hose. However, the stator pump requires an electric motor or gas engine to operate. As such, it is expensive to build and costly to buy and operate. The stator pump is also very inefficient due to tremendous friction, so a large power source is required. Therefore, fluid material delivery systems using a stator pump for drywall work are an expensive way to go, with a market limited to professionals.
A second approach to spraying drywall textures is a hopper device with a gun and compressed air, which atomizes the material. This device is less expensive than pump units. However, it must be held overhead in the case of ceiling texturing, thus making its use very messy and tiring due to the stress of holding a heavy hopper full of texture overhead for extended periods. Presently, a gun on a hose is by far the preferred tool for texture application; however, such a device is currently too expensive for “do-it-yourself”, non-professional users.
An ideal system would be one in which the automatic tape functions of the Ames System are combined with the preferred spray functions of a material pump with a gun on a hose in such a way as to provide for an inexpensive solution for “do it your self” users. In such a system, the disadvantage in existing systems of carrying drywall mud back and forth will be reduced since the material is delivered by hose directly to the wall.
Examples of such a drywall taping and texture system are described in U.S. Pat. No. 6,299,686. In various embodiments discussed therein, the system includes various interchangeable tools that connect to a pump. A pump residing in a housing forces fluid drywall material through a material line. A control line hose also runs from the pump to the various tools.
The tools may include a button or trigger, allowing the user to remotely control the function of the pump by covering or uncovering an air release hole on the tool that is inter-connected to the control line to the pump. The control line outlet to the atmosphere is “normally open” at the distal, tool end. To close the control line, a plug is inserted into the air release hole to the atmosphere. Thus, opening the control line to the atmosphere releases air and resets the pump, whereas closing the control line starts the pumping action.
Additional air release mechanisms may be also be included in the pump housing itself, such as a pneumatic automatic flip flop logic switching system. This function may be performed in several ways. For example, in various embodiments of the invention of U.S
Mancene Gene
Nicolas Frederick
Pillsbury & Winthrop LLP
Spraytex, Inc.
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