System for applying finishing compound

A system for finishing surfaces with a finishing material includes a handle assembly with proximal and distal ends. A material reservoir is mounted on the handle distal and includes an inlet and an outlet. A material applicator tool is mounted on the reservoir and receives material from the reservoir outlet. A discharge mechanism includes an extendable-retractable component or linear actuator connected to the reservoir for discharging or reloading material. An alternative embodiment includes a lockable, compressible gas spring. Another alternative embodiment includes a rotating element driven by a reversible motor mounted on the handle assembly. The rotating element drives a discharge mechanism in a discharge direction of rotation, and reloads the reservoir in a reload direction of rotation. Multiple alternative embodiments of linear actuators are disclosed. An alternative embodiment includes a push-to-open valve mechanism.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to: tools, equipment, and related devices that dispense semi-fluid compounds; procedures for using same; and in particular to an applicator system for finishing drywall and other surfaces.

2. Description of the Related Art

Drywall installation typically involves joining two or more panels or sheets of gypsum board together to create a larger surface, such as a wall or ceiling. This is accomplished by taping the joints and covering the tape with joint compound (or “mud”). Additional applications of mud can be used depending on the specified level of surface finish. Some drywall finishers prefer to apply the mud by hand using putty knives, but this can be a time-consuming process. To semi-automate the process, tool manufacturers have created “flat boxes” comprising reservoirs attached to handles for guiding along gypsum board or drywall joints. The flat boxes apply joint compound, normally over a strip of joint tape, along joints. The joint compound can be sanded and re-coated as necessary to achieve the specified finish level. There are also corner tools and associated reservoirs that apply mud to corner joints. The user applies pressure via a handle assembly to dispense the mud while pushing or pulling such applicators along the drywall joints.

Previous drywall finishing tools include the Continuous Flow Paste Applicator for Dry Wall shown in U.S. Patent Publication No. 2001/0003563, but the connected hoses required by this applicator can be unwieldy. Other prior art finishing systems include components that must be carried around with handle systems, e.g., as shown in U.S. Pat. No. 6,793,428 for Drywall Joint Compound Applicator Appliance, or that continuously dispense compound until a brake is applied, which can lead to the tool dispensing excess compound.

The embodiments of the present invention address prior art deficiencies with systems and methods for applying compound to work surfaces efficiently and effectively. Finishing operations are thus simplified, resulting in higher quality results in less time and with less expense.

Heretofore, there has not been available a surface finishing system with the features and advantages of the present invention.

SUMMARY OF THE INVENTION

In practicing an aspect of the present invention, a system is provided for automatically applying a finishing compound to a surface, e.g., joint compound (“mud”), which can be applied over joint tape to form a flush or level drywall joint. Modified or alternative aspects of the invention include lockable gas springs, piston-and-cylinder units and drive augers for dispensing the compound from a handle assembly, which can be held by an operator. Power can be applied via compressed springs extending a plunger or electric motors rotating an auger. Various application-specific finishing tools, such as mud knives for flat surfaces and corner tools (e.g., for wall-ceiling and wall-wall intersections), can be mounted on the handle assembly. In practicing another aspect of the present invention, a finishing compound applicator includes a dispensing valve activated by engaging the applicator with a wall surface, whereupon compound is automatically dispensed under pressure until the applicator disengages. In this embodiment the operator merely loads or charges the applicator with compound, engages the work surface (e.g., a wall and/or ceiling), and disengages to halt compound flow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

I. Introduction and Environment

II. First Modified Embodiment or Alternative Aspect of the Invention (FIGS.1-5)

Referring toFIGS. 1-5, a compound application or surface finishing system2employs a compound-dispensing tool4to apply a quantity of material6, such as drywall finishing compound or “mud”, to some other material or surface7, such as taped drywall joints. The compound6can be applied using a removable, interchangeable application tool8(e.g., a drywall compound distribution box) attached to a reservoir16outlet, said reservoir16capable of containing an amount of compound6. In an embodiment of the application system2a pump10is used to move compound6from a source (e.g., a finishing compound bucket as shown inFIG. 5) and into the reservoir16via a fill access port22for reloading or recharging the reservoir16as the material6is applied and used. A plunger18can be employed to push and dispense the material6out of the reservoir16. An embodiment of the invention can also include a ball throttle valve24to control dispensing the compound6from the reservoir16. Part of the compound-dispensing assembly4of the invention can also include one or more openable clamp assemblies20for ease of removing the reservoir from a handle14in order to access, open, or dismantle the assembled tool for cleaning, storage, or for any other reason.

A handle14can extend the distance between a user and the intended application surface7. Various embodiments of certain features of the invention can also be mounted onto or in the handle14.

The extendable-retractable handle14can include one or more sections14a,14b, etc., which can telescope with respect to each other. A pressurized cylinder30can be mounted in the handle14for dispensing a quantity of material6, such as drywall finishing compound or “mud.”

A tool assembly4includes a release lever12, which is actuated by squeezing the lever12towards the body of the handle14, thereby retracting a master rod32which rotates a first embodiment braking mechanism38(in this case, a pinch brake40) thereby releasing a slave rod34which is a piston of the pressurized cylinder30. The piston34is connected to the reservoir plunger18. With the release lever12depressed, gas and/or spring pressure within the cylinder30pushes the slave rod34outwardly for continuous compound6dispensing until the release lever12is released or the handle reservoir16requires recharging with compound material6.

Upon releasing the lever12, a first embodiment brake compression spring42(compressed with the retracted master rod32) expands and extends the master rod32, rotating the pinch brake40of the braking mechanism38in the opposite direction, thereby braking the outward motion of the slave rod34.FIGS. 3, 3A, and 3Brespectively show locked and unlocked positions38a,38bof the braking mechanism38.

Reversing the direction of the slave rod34follows a sequence similar to that of the standard use sequence: squeezing the lever12retracts the master rod32, which rotates the braking mechanism38, thereby releasing the slave rod34, at which point inward pressure on the opposite end of the piston34would re-pressurize the gas and/or spring pressure within the cylinder30with the slave rod34returned to its initial position, ready for the process to be repeated, and for recharging or reloading the reservoir16with drywall compound6.

FIG. 5shows the system2in a charging or loading procedure with joint compound6being loaded into the reservoir16using the pump10, which can be placed in a bucket or other container of joint (drywall) compound. The compound6is pumped into the reservoir16through the inlet access port22.

III. Second Modified Embodiment or Alternative Aspect of the Invention (FIGS.6-11)

A second embodiment or aspect of the invention comprising a system designated102with a compound-dispensing tool104incorporates the use of a cam150in place of a pinch brake40and is shown inFIGS. 6-11. The cam150can include a groove154to increase surface contact between the cam150and a slave rod134, thereby increasing friction and reducing the force necessary to brake the motion of the slave rod134. A master rod132can attach to the cam150by means of a clevis assembly156that accommodates rotation of the cam150.

Similar to the operation of the previous embodiment, upon releasing a release lever112, a second embodiment brake compression spring152squeezed by a retracted master rod132is allowed to expand, thereby extending the master rod132, rotating the cam150of a braking mechanism148(in this case, a cam brake) in the opposite direction, thereby braking the outward motion of the slave rod134.FIGS. 8A and 8Brespectively show a locked position148aand an unlocked position148bof the braking mechanism148.

The handle114can include one or more sections114a,114b, etc. and can be connected to a source of the compound6for reloading or recharging a reservoir116as the material6is applied and used. A reservoir plunger118can be mounted to the end of the slave rod134to ease dispensing. Alternative arrangements for locking and releasing the piston rod134of a piston134and cylinder130unit are provided. These can include, without limitation, rotatable plates, cams, and other braking mechanisms. A non-limiting example of an application for the extendable handle114is a drywall finishing tool104mounting a drywall compound (mud) distribution box8, as well as various other taping, sanding, painting, and finishing tools and equipment.

The system102can, similarly to the previous embodiment, incorporate a fill access port122, a ball valve throttle124, and one or more openable clamp assemblies120to simplify use.

IV. Third Modified Embodiment or Alternative Aspect of the Invention (FIGS.12-18)

A third embodiment or aspect of the invention (FIGS. 12-18) comprising a system designated202with a compound-dispensing assembled tool204incorporates the use of a locking, pressurized gas cylinder268unit (such as those manufactured by Bansbach Easylift of Lorch, Germany, for example) actuated by a release pin264pressed by a projection262of a release lever or trigger mechanism212. Squeezing the release lever212(also referred to as a “trigger”) toward the body of a handle214causes the projection262on the trigger mechanism212to depress the release pin264of a piston rod266of the locking, pressurized gas cylinder268, thereby unlocking it. With the cylinder268unlocked the piston rod266extends and the tool dispenses compound6until the trigger212is released or the handle reservoir216requires recharging with compound material6. A plunger218within the reservoir216is mounted on the end of the cylinder268.

Upon release of the trigger212, the release pin264is no longer depressed and the locking, pressurized gas cylinder268locks, thereby braking the outward motion of the plunger218.

Reversing the direction of the cylinder268follows a sequence similar to that of the standard use sequence: squeezing the trigger212depresses the release pin264, thereby unlocking the pressurized cylinder268, at which point inward (retracting) pressure on the opposite end of the cylinder268would re-pressurize the gas pressure within the cylinder268and return the cylinder268to its initial position relative to the piston rod266, ready for the process to be repeated.

The system202can also include a trigger latch260.FIG. 13Ashows the trigger mechanism212in an un-engaged, extended position. The trigger latch button260extends from the body of the handle214with the trigger mechanism212in its extended, un-engaged position (FIG. 13A). Squeezing the trigger mechanism212inwardly towards the handle214rotates the trigger mechanism212out of the way of the latch260which can then be depressed (FIG. 13B) to retain the trigger mechanism212from rotating back to its un-engaged position. Upon pressing the latch button260again, the latch “pops out” of the way of the trigger212. A trigger compression spring270, compressed by the trigger, can now expand, pushing the trigger212back to its un-engaged position. This arrangement can aid in continuous compound6dispensing without requiring a user to squeeze the trigger the entire time.

Alternatively, the dispensing-locking positions of the trigger mechanism212can be reversed whereby squeezing the trigger mechanism212causes the tool assembly204to dispense material. The operation of the latch260can likewise be changed as appropriate for particular applications and to accommodate user preferences.

The system202can, similarly to the previously-described embodiments, incorporate a fill access port222, a ball valve throttle224, and/or one or more openable clamp assemblies220to simplify use.

V. Fourth Modified Embodiment or Alternative Aspect of the Invention (FIGS.19-27)

Yet another alternative embodiment or aspect of the invention (FIGS. 19-27) comprises a system designated302and including a compound-dispensing tool304driven by a motor unit372at a proximal end of a handle314. The motor unit372is powered by a rechargeable battery374and actuated by a trigger mechanism312. Depressing the trigger312, that is, squeezing it toward the body of the handle314, activates a motor378which receives power from the battery374. The motor378rotates a motor shaft388which, in turn, rotates an auger shaft382and auger384, which advances the compound material6for discharge via an application tool8.

Alternatively, the motor378can drive a threaded shaft threadably connected to a plunger318for expelling the material6contents of the reservoir316. Upon release of the trigger312the motor378is no longer powered and ceases to rotate the shaft382, thereby stopping the discharge flow of material6.

A variable- or static-speed forward/reverse (reverse optional) switch380can be included in the assembled tool304. The switch380can control the speed and rotational direction of the motor378and can be housed with the motor378within the motor housing376. The switch380can include forward and reverse closed positions for dispensing compound6or reloading (recharging) the reservoir316, or retracting the plunger318.

Threaded rods, plungers and other operative components can be utilized with a reversible electric motor, such as the drive motor378. Moreover, compound materials6can be loaded into and discharged from hollow portions of handles (e.g.,314) and/or reservoirs (e.g.,316) using suitable augers or shaft-plunger assemblies, which are rotated by the drive motor378. For example, the threaded shaft386could extend through most of the length of the reservoir316and threadably mount the plunger318thereon for advancing and retracting through the reservoir316in a reciprocating range of motion.

FIG. 22shows a mating connection between the motor378and the auger shaft382. In this mating connection a hexagonal motor shaft388afits into a hexagonally-shaped hub392ainside the auger shaft382. This removable mating connection allows the motor378to rotate the auger shaft382.

Another embodiment of a potential mating connection between the motor378and the auger shaft382is shown inFIG. 23. This embodiment of a mating connection employs a keyed motor shaft388bto fit inside a keyed hub392bwithin the auger shaft. An example key seat394, key396, and key way398are depicted inFIG. 23. The key arrangement shown is one example of a potential key connection and is not intended to be limiting. Keyed connections including other arrangements thereof are common in the art and should be easily understood by one skilled in the art.

The battery374can be recharged by removing it from the assembled tool304and connecting it to a charger390(FIG. 27).

The system302can, similarly to the previous embodiments, incorporate a fill access port322, a ball valve throttle324, and one or more openable clamp assemblies320to simplify use.

VI. Fifth Modified Embodiment or Alternative Aspect of the Invention (FIGS.28-34)

A fifth modified embodiment or alternative aspect of the invention comprises a compound-applying system402including a push-to-dispense tool404with a quantity of finishing compound406in a hollow reservoir416including a bore417. A linear actuator405includes a plunger418mounted on a connecting rod419and reciprocably received in the reservoir bore417for discharging the compound406through a distal, push-to-open valve assembly420, to an angle head applicator408and then onto a work surface or surfaces. For example and without limitation,FIG. 28shows the system402applying compound406to a horizontal, wall-ceiling joint410between a wall407aand a ceiling407bwith the angle head applicator408.FIG. 29shows compound406being applied to a vertical, wall-wall joint412between walls407a.FIG. 34shows the system402with a flat head applicator414, which is adapted for applying compound to a wall joint415.

Typical gypsum board (also known as drywall) construction involves attaching the gypsum board sheets to the wall or ceiling structure, applying perforated, paper, joint tape413(FIG. 34) with a first coat of compound, applying perforated metal or plastic corner-protecting beads, and applying additional coats of compound. After drying and before recoating, each coat is typically sanded with special hand tools. Skilled workers can achieve relatively smooth, flat, planar results by applying a sufficient number of coats of compound and sanding each coat to a smooth surface finish. In the construction trades, drywall finishes are graded based on quality, with level five (5) being considered a top quality, commercial-grade finish, which is generally free of blemishes and imperfections.

The linear actuator405can comprise a gas piston-and-cylinder unit, a compressible spring unit or some other mechanism for advancing the plunger418through the reservoir416. Alternative suitable linear actuators are described above. The reservoir416is refillable through an inlet (fill) port422, which can be connected to a suitable pump for pumping the contents of a compound bucket into the reservoir416in a reloading or recharging operation. A generally conical dispensing head424is mounted on the distal end of the reservoir416by clamps426, which permit field removal for cleaning, servicing, etc. The dispensing head424mounts the valve assembly420.

FIGS. 30 and 31show the push-to-open valve assembly420in a closed position. The valve assembly420includes an outer sleeve430with an externally-threaded proximal end432, which screws into a distal end428of the dispensing head424. The outer sleeve430also includes a tapered, distally-converging section434which generally aligns with the dispensing head424. The valve assembly420also includes an inner sleeve436reciprocably, coaxially positioned within the outer sleeve430and movable relative thereto between the closed position (FIGS. 30, 31) and an open, compound-dispensing position (FIGS. 32, 33). The inner sleeve436includes a proximal end438and a distal end440with a partially spherical collar442. The outer and inner sleeves430,436include respective, coaxial bores435,444.

A valve guide pin446extends diametrically across the bore444and is secured at its ends in receivers448in the threaded, proximate end432of the outer sleeve430. The guide pin446is slidably received in perspective guide slots450formed in the inner sleeve436. A valve452includes a disc-shaped valve head454and a threaded valve shaft456extending coaxially therefrom through a valve shaft hole458formed in the middle of guide pin446. The valve shaft456threadably receives a retaining nut460. A helical compression spring462is compressed between the guide pin446and the retaining nut460with intermediate washers464at the ends of the compression spring462.

The tool404is assembled by snapping the partially-spherical collar442into the socket466formed in the angle head and flat head applicators408,414. The resulting ball-and-socket connection between the collar442and the socket466provides a multi-axis, universal joint swivel connection, enabling the tool404to be positioned at various angles relative to the applicators408,414and the joints410,412,415being finished.

The push-to-open operation of the valve assembly420accommodates relatively simple operation with minimal effort by an operator. More specifically, the compression spring462retains the valve452in a closed position with the valve head454engaging the outer sleeve proximal end432, thus blocking the flow of compound406into the inner sleeve bore444. Pushing the applicator408,414against a surface pushes the inner sleeve436proximally into the reservoir bore417and compresses the return spring462. Passages441in the inner sleeve436are thus exposed to the compound406in the reservoir416. The compound406, under pressure via the plunger418, is forced through the inner sleeve bore444and is distributed onto the work surface by the applicator408or414. Compound flow is halted by merely retracting the tool404from the work surface.

In addition to the simplified operation of the system2with the push-to-release feature described above, the system402accommodates efficient maintenance and cleaning. For example, the valve assembly420can readily be separated from the applicator408or414by un-snapping the ball-and-socket joint468. The valve assembly420can then be unscrewed from the dispensing head424. Unscrewing the nut460releases the valve member452and the return compression spring462. The entire valve assembly420can be further disassembled by tapping the guide pin446through the receivers448, thus releasing the outer and inner sleeves430,436. The separated parts can then be cleaned, maintained and replace as necessary. Other parts of the system2can likewise be efficiently disassembled, cleaned, maintained and replaced.

It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects.