drywall mud pump invention factory

This Invention relates to tools used to install and finish drywall in buildings and to hand pumps for pumping viscous fluids. BACKGROUND OF THE INVENTION

Drywall, also known as gypsum board, wallboard, and plasterboard, is a building material used to finish the interior surfaces of walls and ceilings in houses and other buildings. Rigid sheets or panels of drywall are formed from gypsum plaster, the semi-hydrous form of calcium sulphate (CaSO4.½× H2O), which is typically sandwiched between two layers of heavy paper or fiberglass mats. Drywall sheets are about ½ inch thick and are nailed or screwed in place to form the interior surfaces of the building, and provide fire resistance and sound deadening, among other benefits.

The joints between drywall sheets are typically filled and sealed with strips of paper or fiberglass mat and drywall joint compound, also called “joint compound”, “drywall mud”, or just “mud”. Joint compound may be made, for example, of water, limestone, expanded perlite, ethylene-vinyl acetate polymer and attapulgite. Joint compound is applied as a viscous fluid that is thick enough to maintain its shape while it hardens. In addition to forming joints, drywall mud is used to cover nail or screw heads, form a smooth or flat surface, and provide a texture over the surface. Paint or wall paper is typically applied over the drywall and joint compound.

Workers often specialize in the installation of drywall, and in large projects different crews install the drywall panels (drywall hangers) from those who finish the joints and apply the joint compound (tapers or mudmen). Workers who specialize in drywall installation often use specialized tools to increase their productivity including flat boxes that are tools used to hold joint compound and apply it to drywall joints. Joint compound is often mixed (e.g., with water) or stored in buckets, and drywall mud pumps have been used to pump the mud from the buckets into flat boxes or other tools or containers.

U.S. patent application Ser. No. 11/292,238, publication 2007/0122301 (also by Werner Schlecht) describes a drywall mud pump. However, it was found that in operation pumping drywall joint compound that friction developed within the pump making it difficult to use. Thus, needs or potential for benefit exist for drywall mud pumps that have less internal friction. In addition, needs and potential for benefit exist for drywall mud pumps that are inexpensive to manufacture, reliable, easy to use, that have a long life, that are easy to service and clean, and that are simple in operation so that typical operators can effectively maintain them. Room for improvement exists over the prior art in these and other areas that may be apparent to a person of ordinary skill in the art having studied this document. Summary of Particular Embodiments of the Invention

This invention provides, among other things, certain drywall mud (drywall joint compound) pumps with particular features or capabilities. Various embodiments provide, as objects or benefits, for example, that they have less internal friction than certain prior art pumps. In addition, particular embodiments provide, for instance, as objects or benefits, drywall mud pumps that are inexpensive to manufacture, reliable, easy to use, that have a long life, that are easy to service and clean, that are simple in operation, or a combination thereof. Other benefits of certain embodiments may be apparent to a person of ordinary skill in the art.

In specific embodiments, this invention provides certain drywall mud pumps that include a main cylinder and a rod having two ends, a first end and a second end. In many embodiments, when the drywall mud pump is assembled, the second end of the rod is located within the main cylinder, for example. Various embodiments also include a piston which, when the drywall mud pump is assembled, is also located within the main cylinder and is attached to the second end of the rod. In some embodiments, there is a connection structure between the piston and the second end of the rod, which is configured to allow the second end of the rod to move relative to the piston in a direction that is substantially perpendicular to the axis of the rod. A number of embodiments include a means for allowing the second end of the rod to move laterally relative to the piston within the main cylinder. Further, in some embodiments the piston specifically includes an elongated hole that receives the second end of the rod, and the elongated hole allows the second end of the rod to move laterally relative to the piston.

Various such embodiments further include a pump head, which may have an output aperture, and when the drywall mud pump is assembled, the pump head may be connected to the main cylinder and the rod may pass through the pump head. In some embodiments, the drywall mud pump further includes a handle and a linkage, and when the drywall mud pump is assembled, the handle may be pivotably connected to the first end of the rod, and the linkage may be pivotably connected to the pump head and pivotably connected to the handle, as examples. Moreover, some embodiments may include (e.g., in the pump head) a means for guiding the rod, a means for allowing the rod to pivot as the second end of the rod moves laterally relative to the piston, or both. Further, particular embodiments include a guide having a hole through which the rod slidably passes. Some embodiments include just one guide in the pump head, which may serve as both a guide and as a pivot point for the rod, and in some embodiments, the guide may be shortened to provide for pivoting.

In a number of embodiments, the piston includes an elastomeric piston cup having a first hole, which may be elongated, a top rigid support having a second elongated hole, a bottom rigid support having a third elongated hole, and a flapper having a fourth elongated hole. In some embodiments, when the drywall mud pump is assembled, the second end of the rod passes through each of the first, second, third, and fourth holes, for example. Further, certain embodiments include a means for preventing the piston from rotating about the rod. In some embodiments, as an example, the second end of the rod has a flattened portion, at least the second and third elongated holes are substantially the same size and have substantially the same shape, and, when the drywall mud pump is assembled, are held in a particular orientation by the flattened portion of the second end of the rod.

Even further, in some embodiments, when the drywall mud pump is assembled, the second end of the rod is attached to the piston with a nut (e.g., a lock nut), an elongated washer, or both. Moreover, in some embodiments, the piston cup, the top rigid support, and the bottom rigid support each have at least one passageway therethrough for passage of the drywall mud, and when the drywall mud pump is assembled, the flapper covers the (at least one) passageway substantially blocking passage of the drywall mud when the piston is moving in the main cylinder toward the pump head.

In various embodiments, the piston cup, the top rigid support, and the bottom rigid support each have multiple passageways therethrough for passage of the drywall mud, and the multiple passageways substantially surround the first, second, and third elongated holes. In addition, in some such embodiments, a plurality of the multiple passageways for passage of the drywall mud have at least one curved side and at least one straight side. Additionally, in particular embodiments wherein an elongated washer is provided, when the drywall mud pump is assembled, the washer substantially blocks the elongated hole in the piston to prevent drywall mud from passing through the elongated hole in the piston. In a number of such embodiments, the drywall mud pump may also include a means for controlling the rotational position of the washer.

Further, in some embodiments, the second end of the rod includes a first reduced diameter flattened section and a second reduced diameter flattened section. In some such embodiments, for example, the second reduced diameter flattened section has a smaller diameter, thickness between flats, or both, than the first reduced diameter flattened section. Further, in some embodiments, the second end of the rod also includes a threaded section. Further still, in some embodiments, when the drywall mud pump is assembled, the second end of the rod passes through each of the first, second, third, and fourth elongated holes such that the fourth elongated hole is located at the first reduced diameter flattened section, and the first, second and third elongated holes are located at the second reduced diameter flattened section. In addition, various other embodiments of the invention are also described herein. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 7 is an isometric exploded view of the piston, rod, and pump head of the example of a mud pump of the previous figures, except that the piston in FIG. 7 is not shown exploded;

The drawings illustrate, among other things, a particular example of an embodiment of the invention, and various examples of characteristics thereof. Different embodiments of the invention include various combinations of elements shown in the drawings, described herein, known in the art, or a combination thereof. DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENTS

FIG. 1 illustrates an example of an assembled drywall mud pump, pump 10. Parts and features that are visible from the outside in this view include output aperture 11 in pump head 14 where drywall mud emerges from pump 10 when handle 12 is moved, for example, by an operator of drywall mud pump 10. In some embodiments, a detachable high filler (not shown) may attach to aperture 11 (e.g., with the nuts 11 nshown) and may extend the location where the mud emerges to a higher elevation to enhance ergonomics. FIG. 2 is an exploded view of the same embodiment of drywall mud pump 10 shown in FIG. 1.

In the embodiment illustrated, rod 13 passes through pump head 14 (visible in FIG. 1 through aperture 11) into main cylinder 15. Pump head 14 is mounted on or connected to main cylinder 15, in this embodiment, with clips 25. Also in this embodiment, handle 12 is pivotably connected to the top or first end 21 of rod 13 with pin 23, and linkage 16 is pivotably connected at the top (of linkage 16) to handle 12 and at the bottom (of handle 16) to pump head 14 with bolts 26.

Other visible parts of pump 10 include foot plate 18, which is connected to pump head 14 with bolts 28, in this embodiment, and foot valve 19, which is connected to the bottom end of cylinder 15 with pin 29.

When in use, main cylinder 15 may extend into a bucket of drywall joint compound or mud while foot plate 18 may extend outside of the bucket to the floor. The operator may place his foot on foot plate 18 to steady pump 10 while moving handle 12. Foot valve 19, in the bottom of the bucket, may form or include a check valve that may allow mud to flow upward into cylinder 15, but may substantially prevent mud from flowing downward out of cylinder 15 through foot valve 19. Rod 13 also passes through shortened guide 17, in this embodiment, and guide 17 is attached to pump head 14 with bolts 27. Thus, guide 17 is easily removable and replaceable.

FIG. 2 also introduces piston 20, which, in this embodiment, includes several different components that will be discussed in more detail with reference to other figures. In this embodiment, when drywall mud pump 10 is assembled, piston 20 is located within main cylinder 15 and is attached to the bottom or second end 22 of rod 13. In addition, when drywall mud pump 10 is assembled, second end 22 of rod 13 is also located within main cylinder 15. When an operator pushes handle 12 down, piston 20 goes up toward pump head 14, pushing drywall mud that is in cylinder 15 out through aperture 11. During this process, a vacuum is created below piston 20, which draws more drywall mud into cylinder 15 through foot valve 19. When the operator pulls handle 12 up, piston 20 goes down, away from pump head 14, foot valve 19 prevents the drywall mud below piston 20 from exiting cylinder 15 through the bottom, and drywall mud flows through piston 20, as will be described in more detail below.

During the operation of mud pump 10, horizontal or lateral forces are exerted on rod 13. Even if the operator only exerts vertical forces on handle 12, since linkage 16 is not vertical during most of the stroke of piston 20, linkage 16 exerts lateral forces on handle 12, which are carried by handle 12 to rod 13. These horizontal or lateral forces on rod 13 are believed to cause increased friction or binding within prior art drywall mud pumps. In a number of embodiments, drywall mud pump 10, and various other drywall mud pumps in accordance with this invention, allow rod 13 to move laterally without binding (or with reduced binding) and in a manner that reduces friction (e.g., within mud pump 10). In different embodiments, such a reduction in friction makes the drywall mud pump (e.g., 10) easier to use. In addition, in many embodiments, reduced friction reduces wear, thus increasing pump life, maintaining a level of pump performance for a longer time, reducing the need for replacement of parts, reducing the need for servicing of the pump, or the like.

In a number of embodiments, piston cup 44 may be an elastomeric material such as rubber or a synthetic equivalent thereof. Other components shown in FIGS. 3 and 4 may be metal, such as steel, stainless steel, brass, bronze, aluminum, or the like, or may be made of a plastic, a polymer, or nylon, for example. In the embodiment illustrated, piston cup 44 has an outside diameter that is slightly larger than the inside diameter of main cylinder 15. Thus, an interference fit may exist between piston cup 44 and main cylinder 15, and when piston 20 is inside main cylinder 15 (e.g., when drywall mud pump 10 is assembled), the outside diameter of piston cup 44 may contact the inside surface of main cylinder 15.

Flapper 46, in this embodiment, has an outside diameter that is less than the outside diameter of piston cup 44, less than the inside diameter of main cylinder 15, and may be less than the outside diameter of bottom wiper support 43, top wiper support 45, or both. In this embodiment, Flapper 46 has a diameter that is sufficiently small to allow drywall mud to flow between flapper 46 and the inside surface of main cylinder 15, for example, when piston 20 is traveling downward (e.g., away from pump head 14). In the embodiment illustrated, flapper 46 is rigid. In other embodiments, flapper 46 may be flexible. In some embodiments, flapper 46 (or an alternative flapper) may bend or pivot out of the way of the flow of drywall mud when piston 20 is traveling downward, for example. In some embodiments, a flapper or component analogous to flapper 46 may be made of two or more pieces, which may be different materials and may have different stiffnesses.

In the embodiment illustrated, piston cup 44 of piston 20 has a first elongated hole 44 h, top support 45 has a second elongated hole 45 h, bottom support 43 has a third elongated hole 43 h, and flapper 46 has a fourth elongated hole 46 h. In the embodiment shown, when drywall mud pump 10 is assembled, second end 22 of rod 13 passes through each of the first, second, third, and fourth elongated holes (i.e., 43 h, 44 h, 45 h, and 46 h). Further, the embodiment illustrated includes a means for preventing piston 20 from rotating about rod 13. Specifically, in the embodiment illustrated, second end 22 of rod 13 has first and second flattened portions 49 and 48, which, in this embodiment, each have a reduced diameter from the remainder of rod 13. In this embodiment, the second and third elongated holes (i.e., holes 45 hand 43 hin top and bottom supports 45 and 43) are substantially the same size and have substantially same shape, and, when drywall mud pump 10 is assembled, are held in a particular orientation by second flattened portion 48 of second end 22 of rod 13.

In the embodiment illustrated, second reduced diameter flattened section 48 has a smaller diameter and thickness between flats than first reduced diameter flattened section 49. Other embodiments may have different sections that just have different diameters or different thicknesses between flats. Further, in the embodiment shown, second end 22 of rod 13 also includes threaded section 47, which in this embodiment, receives nut 41. Further still, when drywall mud pump 10 is assembled, second end 22 of rod 13 passes through each of first, second, third, and fourth elongated holes 43 h-46 hsuch that fourth elongated hole 46 his located at first reduced diameter flattened section 49, and first, second and third elongated holes 43 h-45 hare located at second reduced diameter flattened section 48.

In the embodiment shown, flattened portion 49 has a sufficient dimension in the axial direction (i.e., of the longitudinal axis of rod 13) to allow flapper 46 to move away from top support 45 when piston 20 is traveling downward away from pump head 14. This allows room for the drywall mud to flow outward between flapper 46 and top support 45 before flowing around the outside of flapper 46. When piston 20 travels in upward, toward pump head 14, flapper 46 moves in the axial direction to the other end of flattened portion 49 until flapper 46 makes contact with top support 45.

As used herein, a means for allowing an end of a rod to move laterally relative to a piston does not include motion resulting from prior art magnitude clearance between the rod and the piston in a drywall mud pump, movement resulting from deformation of an elastomeric piston cup, or deformation of the rod or other components resulting from stress imposed thereon. Rather, a means for allowing an end of a rod to move laterally relative to a piston requires a structure that provides for substantially more lateral movement of the rod under substantially less force than prior art mud pump technology provided. In this context, as used herein, “substantially” means by a factor of at least two.

In different embodiments, the second end 22 of rod 13 may be able to move laterally relative to piston 20 by at least or about 1/16, ⅛, 3/16, ¼, 5/16, ⅜, 7/16, ½, 9/16, ⅝, ¼, ⅞, 1, 1 ⅛, 1 ¼, or 1 ½, inch, or 2 inches, for example, under lateral forces normally present within such a drywall mud pump. In the embodiment illustrated, the elongated hole (e.g., 43 h) in piston 20 is centered within piston 20. But in other embodiments, the elongated hole may extend from the center of piston 20 in one direction, or may extend farther on one side of center than the other, as examples.

Bottom support 43 also includes multiple passageways 53, 54, 55, and 56 therethrough for passage of drywall mud. These passageways 53, 54, 55, and 56 substantially surround (third) elongated hole 43 h. As shown in FIG. 4, in the embodiment illustrated, corresponding passageways having substantially the same shape extend through piston cup 44 and top support 45 and substantially surround (first and second) holes 44 hand 45 h, as well. Drywall mud flows through these passageways (e.g., 53-56), between top support 45 and flapper 46, and around the outside of flapper 46 (i.e., between flapper 46 and the inside of main cylinder 15) when piston 20 is moving downward (i.e., away from pump head 14).

Still referring to FIG. 5, in the embodiment illustrated, all four of the multiple passageways 53, 54, 55, and 56 for passage of drywall mud have at least one curved side 57 and at least one straight side 58, as labeled, for example, for passageway 56. In the embodiment illustrated, the shape of passageways 53, 54, 55, and 56 provides for essentially as much area for the flow of drywall mud therethrough as possible, while maintaining adequate structural strength of the components (e.g., bottom support 43, piston cup 44, etc.).

As mentioned, when piston 20 is traveling upward (i.e., toward pump head 14) in cylinder 15, flapper 46 makes contact with top support 45, blocking or substantially blocking passageways 53, 54, 55, and 56, thus preventing significant quantities of the drywall mud from flowing back through passageways 53, 54, 55, and 56. As used herein, in the context of blocking the flow of drywall mud, “substantially blocking” means blocking more than 90 percent of the cross sectional area (e.g., of passageways 53, 54, 55, and 56), and “blocking” (i.e., without being preceded by “substantially”) means blocking more than 99 percent of the cross sectional area (e.g., of passageways 53, 54, 55, and 56). Blocking or substantially blocking of passageways 53, 54, 55, and 56, in the embodiment illustrated, causes the drywall mud within cylinder 15 to exit through pump head 14 and orifice 11 when piston 20 travels upward (i.e., toward pump head 14).

Further, as shown for example in FIG. 3, in the embodiment illustrated, when drywall mud pump 10 is assembled, washer 42 blocks or substantially blocks the elongated hole (e.g., 43 h, 44 h, 45 h, and 46 h) in piston 20 to prevent drywall mud from passing through the elongated hole in piston 20 (e.g., when piston 20 is moving upward toward pump head 14). In a number of such embodiments, the drywall mud pump (e.g., 10), piston (e.g., 20), or rod (e.g., 13) may also include a means for controlling the orientation or rotational position (i.e., about the longitudinal axis of rod 13) of the washer (e.g., 42). This may facilitate washer 42 blocking or substantially blocking the elongated hole (e.g., 43 h).

FIG. 6 illustrates piston 20, rod 13, pump head 14, and shortened guide 17, all assembled. In this view, flapper 46 is shown against upper guide 45 (not visible) blocking or substantially blocking passageways 53, 54, 55, and 56, as would be the case when piston 20 is moving toward pump head 14. FIG. 7 shows these same components of drywall mud pump 10 in an exploded view, except that piston 20 is not separated into components or separated from rod 13. FIG. 7 shows, among other things, that below guide 17 is a wiper or rod seal 77, which may be made of an elastomeric material or synthetic rubber, for example, and may serve to prevent or substantially prevent drywall mud from within main cylinder or pump head 14 from traveling up along rod 13 through guide 17. Rod seal 77 may have a U-shaped cross section, for example, with the opening of the U pointed downward (i.e., toward piston 20). In other embodiments, rod seal 77 may have a cross section that is square, rectangular, triangular, trapezoidal, a parallelogram, or round, as examples, and may be solid or hollow.

FIGS. 8 and 9 illustrate more detail of the example of guide 17 of the embodiment illustrated. Guide 17, in this embodiment, includes hole 80h through which rod 13 passes when drywall mud pump 10 is assembled. Some embodiments may include (e.g., in pump head 14) a means for guiding rod 13, a means for allowing rod 13 to pivot (e.g., without binding) as second end 22 of rod 13 moves laterally relative to piston 20, or both. In the embodiment illustrated, guide 17 is a shortened guide, and rod 13 slidably passes through hole 80 hwhen pump 10 is assembled. Prior art guides for drywall mud pumps typically have a gland nut with a dimension 90 t(shown in FIG. 9) in the direction of the longitudinal axis of rod 13 that is ¾ inch or more. In the embodiment illustrated, guide 17 has a dimension 90 tof 0.300 inches. Other embodiments may have a dimension 90 tthat is more than ⅛, 3/16, or ¼ inch, and less than ½, ⅜ or 5/16 inch, or the like, as examples. As used herein, a “shortened guide” has a dimension 90 tthat is less than ½ inch.

In some embodiments, guide 17 serves both as a guide and as a pivot point for rod 13. In some such embodiments, the outside diameter of rod 13 and the inside diameter of hole 80 hare selected to provide sufficient clearance between rod 13 and hole 80 hto allow second end 22 of rod 13 to move laterally over, for instance, the full range of the elongated hole (e.g., 43 h, 44 h, 45 h, 46 h, or a combination thereof) in piston 20 without causing binding between rod 13 and hole 80 h, for example, within guide 17. Further, in the prior art, upper and lower guides were used at the top and bottom of the pump head (e.g., otherwise similar to pump head 14). This provided little opportunity for the rod (e.g., similar to rod 13) to pivot in the pump head, and (as used herein) no means for allowing the rod to pivot as the second end of the rod moves laterally relative to the piston. In the embodiment shown, only one (i.e., a single) guide (17) is provided, and guide 17 is shortened, which (as used herein), if sized or shaped in certain ways, may provide a means for allowing rod 13 to pivot without binding as second end 22 of rod 13 moves laterally relative to piston 20.

In some embodiments, hole 80 his manufactured as a right circular cylinder (e.g., a drilled hole), but quickly “wears in” when in use, to a shape that is elongated, for instance, with the most pronounced elongation at the top or bottom surface (or both) of guide 17. In some such embodiments, guide 17 is made of a relatively soft material, such as brass, and rod 13 is made of a harder material, such as stainless steel, which may be grade 420 stainless steel, and may be hardened to 35 Rockwell C (HRC), for example. In particular embodiments, rod 13 has an outside diameter of 0.626±0.005 inches, and hole 80 hin guide 17 has an inside diameter of 0.640±0.003 inches, for instance. In various such embodiments, friction in the operation of pump 10 may be greater when pump 10 is new, but may decrease once guide 17 wears in and binding between guide 17 and rod 13 declines or ceases. Such a shortened guide 17 that is configured to “wear in” to a shape that does not bind against rod 13, as used herein, is another example of a means for allowing rod 13 to pivot as second end 22 of rod 13 moves laterally relative to piston 20.

In the embodiment illustrated, once guide 17 wears in, and binding between guide 17 and rod 13 declines or ceases, the rate at which guide 17 wears may decrease substantially. However, in cases of frequent use of pump 10, guide 17 may continue to wear over time with continued use. At some point, guide 17 may be replaced. In the embodiment shown, guide 17 and seal 77 are easily replaceable by removing pin 23 and bolts 27.

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.

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. Pat. No. 6,299,686, this may be achieved electronically, with sensors and an electrical solenoid pneumatic valve, and/or mechanically, with a two-stage pressure relief valve. Both of these approaches provide for a less-expensive way of building and operating a bladder pump control than is available in previous mud pumping systems. In addition, in both cases, the device may be remotely controlled by an operator and run on a small, inexpensive air compressor of ¼ horsepower. Still, improvements may be made in the bladder pump and pneumatic system.

Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, various features of embodiments of the invention.

A detailed description of embodiments of the invention will be made with reference to the accompanying drawings, wherein like numerals designate corresponding parts in the several figures.

FIG. 3a is a perspective view of the interior parts of the pump shown in FIG. 1. FIG. 3b is a partial cross-sectional view of the interior of the pump shown in FIG. 1.

FIGS. 4a and 4b are partial cross-sectional views of the interior of the pump illustrating the pump in action. FIG. 4a shows the pump during intake of drywall material, and FIG. 4b shows the pump during exhaust of drywall material.

FIG. 5a is a side, cross-sectional view of a pump cap in accordance with an embodiment of the present invention. FIG. 5b is a top plan view of the pump cap, and FIG. 5c is a perspective view of the pump cap.

FIGS. 6a-6d are views of seat and ball components of a valve in accordance with an embodiment of the present invention. FIG. 6a is a cross-sectional view of a seat in accordance with an embodiment of the present invention. FIG. 6b is a perspective view of the seat, and FIG. 6c is a top plan view of the seat. FIG. 6d is a cross-sectional view of a ball in accordance with an embodiment of the present invention.

FIGS. 8a and 8b are perspective views of a button with a hole, which is an air release mechanism in accordance with an embodiment of the present invention. FIG. 8a depicts the air release mechanism in the open position, and FIG. 8b depicts the air release mechanism in the closed position.

FIGS. 9a-9c are views of an electrical version of the pump in accordance with an alternative embodiment of the present invention. FIG. 9a is a partial cross-sectional view of the interior of the pump. FIG. 9b is an exploded perspective view of a solenoid module for controlling the electrical version of the pump. FIG. 9c is an exploded, partial cross-sectional view of an inflation sensor for electronically sensing the condition of the bladder.

FIGS. 11a-11c are views of a pneumatic tape cutter in accordance with an embodiment of the present invention. FIGS. 11a and 11b are partial cross-sectional views of the pneumatic tape cutter. FIG. 11c is a cross-sectional view of the pneumatic tape cutter.

FIGS. 12a and 12b are views of a wand tool in accordance with an embodiment of the present invention. FIG. 12a is a perspective view of the wand tool, and FIG. 12b is a partial cross-sectional view of the wand tool.

FIGS. 18a-18c are views of adapter parts that allow use of the pump with Ames Tool Company"s tools in accordance with an embodiment of the present invention. FIG. 18a shows perspective and top plan views of an Ames adapter button. FIG. 18b is a perspective view of an Ames adapter gooseneck. FIG. 18c shows perspective and top plan views of an Ames adapter box filler.

FIGS. 19a-19e are views of an universal tool fitting part in accordance with an embodiment of the present invention. FIGS. 19a and 19b are cross-sectional views of the universal tool fitting part, FIG. 19c is a perspective view of the universal tool fitting part, and FIGS. 19d and 19e are cross-sectional views of components of the universal tool fitting part.

FIGS. 21a-21e are views of a wheel with a hollow axle, which is a wheel air release mechanism in accordance with an embodiment of the present invention. FIGS. 21a and 21b are cross-sectional views of a wheel taken through the point at which air holes are located, depicting the wheel with a wheel air hole surrounding a hollow axle with an axle air hole. FIGS. 21c and 21d are cross-sectional views depicting the same wheel taken through the point at which material dispensing holes are located, depicting the wheel with multiple material dispensing holes around the same hollow axle with a material hole. FIG. 21e is a cross-sectional view of the same wheel, the cross-section taken at a plane perpendicular to those in FIGS. 21a-21d, depicting a wheel with a wheel air hole and multiple dispensing holes around a hollow axle with an axle air hole and an axle material hole.

FIGS. 22a-22b are views of an air release mechanism in accordance with an embodiment of the present invention. FIG. 22a is a perspective view of a pressure release valve situated on a housing. FIG. 22b is a perspective view of a pressure release valve in the closed position.

FIGS. 24a and 24b are partial cross-sectional views of the interior of the pump depicted in FIG. 23, illustrating the pump in action. FIG. 24a shows the pump during exhaust of drywall material, and FIG. 24b shows the pump during intake of drywall material.

FIG. 25 is a perspective exploded view of a bladder pump with pneumatic pressure relief valve in accordance with the pump depicted in FIGS. 23 and 24.

FIG. 26a is a perspective view of the interior valve core assembly parts of a pump in accordance with an embodiment of the present invention. FIG. 26b is a partial cross-sectional view of the parts of this same embodiment.

FIG. 27a is the pump at rest, 27b is the pump with bladder filling, FIG. 27c is at valve opening, FIG. 27d is at bladder discharge, FIG. 27e is at valve closing.

FIG. 33 is a drawing of a bladder pump that uses electrical sensors and a magnet on the bladder to operate, with a schematic for the sensors, electro-pneumatic valve, latching relay and power input.

As shown in the drawings for purposes of illustration, the invention is embodied in a drywall taping and texture system and a pump. In preferred embodiments of the present invention, the drywall taping and texture system utilizes the pump and various tools connected to the pump for applying drywall tape, as well as mastic or fluid drywall mud and texture, to wall surfaces. However, it will be recognized that the disclosed bladder pump may be used in other systems and with other fluids, such as water, oil, gas, or the like.

FIG. 1 shows a perspective view of a drywall taping and texture system using a pump in accordance with an embodiment of the present invention. The drywall taping and texture system preferably includes a pump 1 immersed in a container of mastic or fluid drywall material 32. The pump 1 may be supported in the container by a bucket clip 22. Referring to FIGS. 1 and 2, the pump 1 is preferably contained within a generally cylindrical housing 29. The housing 29 may be a solid shell with strength to withstand changes in pressure within the pump 1 and to support various parts of the pump 1. The housing 29 may be manufactured from a plastic extrusion, such as simple plastic drain pipe, which is cut to an appropriate length and then drilled to hold fasteners, such as screws or the like, that penetrate into various parts of the pump 1. The pump 1 may include a cap 10 attached to the housing 29 using fasteners such as a pin or bolt, or the like. The pump cap 10 may further include an air stem fitting 13 for connecting to an air compressor 28; a material line fitting 26 for connecting a preferably plastic material line 14 to the pump 1; and a control line fitting 27 for connecting a preferably plastic control line 15 to the pump 1. The material line 14 and the control line 15 may attach at their respective distal ends through another material line fitting 26 and another control line fitting 27, respectively, to a variety of tools, such as a tape applicator tool 200, a wand tool 300, a mud knife tool 400, a mud bead tool 500, a wall texture spray tool 600, or an acoustic texture spray tool 700. The pump 1 may also be attached to a variety of tools manufactured by Ames Tool Company See FIG. 18a-c and the like, through adapter parts 800, 801, and 802.

In the embodiment illustrated in FIGS. 1 and 2, the pump 1 preferably has an air gauge 24 and a pressure relief valve 25. The pressure relief valve 25 is one type of air release valve or mechanism for releasing air from the drywall taping and texture system, as will be discussed below. In alternative embodiments, the air gauge 24 and the pressure relief valve 25 may be omitted.

As shown in FIGS. 3a and 3b, the bottom of the pump 1 may include an intake orifice 8 covered with a screen 9, which may be a barrier to particulate matter that might ruin the drywall finish or plug the tool attached to the pump 10. The mesh size of the screen 9 is preferably large enough to allow passage of acoustic ceiling grains, but small enough to stop larger particles. A user may change the screen 9 to screen mud or to spray acoustic. The screen 9 may be positioned over the intake orifice 8 so that all drywall material 32 passes through the screen 9 prior to entering the pump 1.

In preferred embodiments, the pump 1 has upper and lower valves for controlling the flow of the drywall material 32. In preferred embodiments, the valves are check valves that create a one-way flow of the drywall material 32 upward through the pump 1. In the embodiment illustrated in FIGS. 3a-4b, each valve includes a seat 3 or 7 having an orifice 17 or 8, respectively, through which the drywall material 32 flows, and a member 2 or 6 for controlling the flow of the drywall material 32 through the orifice 17 or 8, respectively. See FIG. 6a-d. However, in alternative embodiments, the valves may include other components, such as flappers or the like. The lower valve is preferably formed from a lower seat 7 and a lower member or ball 6. The upper valve may be similarly formed from an upper seat 3 and an upper member or ball 2. The upper and lower members may, in some embodiments, be formed as a plug, as illustratively depicted in FIGS. 23, 24, 26 and 27.

Referring to FIGS. 3a-4b and 6a-6d, the upper and lower seats 3 and 7 may be generally shaped as a band or ring, configured to fit with the upper and lower balls 2 and 6, respectively. The seats 3 and 7 may be secured to the housing 29 using fasteners, such as screws, glue, bolts, or the like. Drywall material 32 may flow through an orifice 8 at about the center of the seat 3 or 7. The seat 3 or 7 may include a raised ring that contacts the ball 2 or 6, respectively, to separate granular elements from the drywall material 32 for proper sealing of the seat 3 or 7 and the ball 2 or 6, respectively. In alternative embodiments, the seat 3 or 7 may have other shapes.

In the illustrated embodiment, the lower seat 7 holds the screen 9. The intake orifice 8 in the lower seat 7 may alternatively have lateral vents so that pump 1 is not closed off by contact with the bottom of the container of drywall material 32.

Preferably, the upper and lower balls 2 and 6 are similar. The ball 2 or 6 is preferably made from a heavyweight material, such as iron, lead, or the like, and covered with a soft rubber or rubber-like material, such as elastromeric material or the like. The rubber or rubber-like material may help the ball 2 or 6 to seal with the seat 3 or 7 when stopping the backwards flow of the drywall material 32. By way of example, the ball 2 or 6 may be a solid material ball with a rubber coating, a rubber ball with a lead shot filling, or a spring-loaded ball. Most preferably, the ball 2 or 6 plugs the seat 3 or 7, respectively, when the drywall material 32 flows backwards, but does not stick in the orifice 17 or 8 of the seat 3 or 7, respectively. The upper and lower valves may thus create a one-way flow of the drywall material 32 upward through the pump 1.

The pump 1 may include a bladder 5 mounted within the housing 29 between the upper and lower valves. Referring to FIGS. 3a-4b and 7, the bladder 5 may be made from a resilient, rubber or rubber-like material, such as elastomeric material or the like, with a diameter smaller than the diameter of a material chamber 4 of the pump 1. When inflated, the bladder 5 could be larger than the material chamber 4, but is preferably restrained by the cylinder body pump housing 29. The rubber-like material of the bladder 5 preferably has a plastic memory and will resiliently seek from a hyper inflated state to return to its “normal size” (uninflated).

The bladder 5 may be inexpensively built and easily replaced using adjustable bands 108 that clamp a rubber cylinder between them and the bladder attachment to pump head part 115 at the top and the lower bladder part 116 at the bottom. An alternative bladder 5 forming arrangement may be provided using a plurality of bladder clips 11 which seal the top and bottom of the bladder 5.

Referring to FIGS. 4a and 4b, when the pump 1 is placed in the container filled with mastic or fluid drywall material 32, drywall material 32 preferably wants to flow into the pump 1. The lower ball 6 may be lifted out of the lower seat 7 due to greater pressure outside the pump 1 and lower pressure inside the pump 1. Resistance to the flow of the drywall material 32 from the container into the pump 1 may be minor because the lower valve resists flow in the opposite direction. Once the pump 1 is filled with drywall material 32, the bladder 5 may be inflated, resulting in positive pressure within the pump 1. This pressure may close the lower valve and lift the upper ball 2 out of the upper seat 3, forcing drywall material 32 through the material line 14 and the attached tool, and onto the work surface.

An automatic air release mechanism may be included to vent air from the bladder of the system. When the air release mechanism is open the bladder will deflate, pulling more drywall material into the housing. When the air release mechanism is closed, however, air may enter and inflate the bladder, forcing drywall material to the work surface via a control line and tool. Multiple air release mechanisms may be included in particular embodiments of the present invention, and most preferably at least one such mechanism is included (e.g., a button 50 or a trigger 147) and a pump mounted pressure relief valve.

Each tool preferably includes an air release mechanism, such as a button 50 or trigger 147, that allows the user 146 to remotely control the pump I, via the control line 15. In particular, the user may utilize the air release mechanism to deliver drywall material 32 to the work surface as needed and to control an air release valve or mechanism remotely located on the pump 1 (i.e., when an air release mechanism included on the tool is continually sealed, a second automatic air release mechanism on the housing may be forced to open). FIGS. 8a-8b, 21a-21e, 22a-22c and FIG. 35a illustrate four types of such tool related air release mechanisms.

Referring to FIGS. 22a-22c, an air release mechanism may be a pressure relief valve 25 connected to the pump housing 29. The pressure relief valve 25 may include a pull ring 31, a valve core 34, and a valve body 33. The pressure relief valve 25 may also include an added compression spring 30 inserted over and surrounding the valve core 34, to dampen closing to thus expand the range of pressure variation during which pressure relief valve 25 remains in the open position. The pressure relief valve 25 preferably opens momentarily when the bladder 5 inflates to a maximum air pressure level, and the pressure relief valve 25 preferably closes (FIG. 22b) when the bladder 5 deflates to a minimum air pressure level. Absent spring element 30, or another similar mechanism, pressure relief valve 25 may open when bladder 5 reaches a maximum air pressure level and may close once the pressure drops slightly below this maximum level. Thus, in a preferred embodiment, spring element 30 possesses sufficient mechanical and elastic properties such that pressure relief valve 25 opens at a maximum air pressure level of approximately 80 psi, and remains open until the pressure drops to a minimum pressure level of approximately 40 psi. This same preferred pressure relief valve 25 may close at a pressure level of approximately 60 psi when spring element 30 is not included therein. A two stage air release regulator (not shown) which opens at 80 psi and closes at 10 psi may be used but is much more expensive than the modified pressure relief valve 25, with a simple spring 30.

The trigger 147 may be used on a number of various tools to release air which controls the pump. The trigger best shown on FIG. 35a shows a rubber air seal washer 162 which is attached to the under side of the trigger 147 such that as the trigger is pulled back by the user operator 146, the air flow from the control line 15 is selectively held to remotely start pump action.

Therefore, in preferred embodiments, each tool has a button or trigger 147, for remotely controlling the pump 1 via the control line 15. When the user presses the button 50, or pulls the trigger, the normal release of air at the tool is stopped and air release at the pump 1. The default condition of the pump bladder is deflated and the control valve default is closed. Pressure then builds up in the control line 15 and causes the bladder 5, to inflate, thus forcing drywall material 32 through the upper valve and out of the pump 1, through the material line 14 and the tool, and onto the work surface. After a surge of a certain volume of drywall material 32, the user may reduce the air pressure by releasing air at the tool by releasing the trigger preferably included therein. The bladder 5 quickly deflates upon the release of air through the button 50 or trigger 147. The resulting partial vacuum formed by the shrinking bladder 5 refills the material chamber 4 of the pump 1 with drywall material 32 through the lower valve. Subsequent inflation of the bladder 5 forces drywall material 32 through the upper valve, as previously discussed.

When a more continuous flow of drywall material 32 is desired, a pressure relief valve may be additionally included such that the user may continuously hold down the trigger 147 on the tool. This may cause the pressure within the bladder 5 to rise until the maximum air pressure level of the pressure relief valve is reached. At that point, the pressure relief valve preferably opens, deflating the bladder and drawing fresh drywall material into the housing. The pressure relief valve preferably closes once pressure drops to a minimum air pressure level, causing the bladder to again inflate and force drywall material to the work surface. Notably, a trigger 147, if included on the tool, need not be released for this continuous, cyclic action of the device, sometimes referred to as a “flip flop” action controlled by pneumatic logic.

Where periodic, user-controlled extrusions of drywall material onto a work surface are desirable, a trigger may be sufficient as a sole air release mechanism in the tool. However, in alternate embodiments, such as the mud bead tool 500 depicted in FIGS. 15a-15b, the additional inclusion of a second air release mechanism in the tool may allow air to periodically be released from the bladder even while the aforementioned button is depressed, thereby cyclically refilling the pump housing with drywall material as the bladder deflates with each release of air from the additional air release mechanism. This feature allows the tool to be used continuously, without the user having to release the button on the tool at particular time intervals to refill the housing with drywall material. This is particularly advantageous when the tool is one where a substantially consistent flow of drywall material is desired, as opposed to a periodic extrusion. In this latter embodiment, the trigger may need only be released when the user desires to terminate the extrusion of drywall material from the tool altogether. In a most preferred embodiment of the system used with a mud bead tool, three air release mechanisms may be included: a button 50, or trigger 147, on the tool as a pressure relief valve, and a wheel air release mechanism as well.

FIGS. 9a-9c illustrate an electrical version of the pump 1 in accordance with an embodiment of the present invention. An air compressor 28 may be mounted within the pump housing 29 and connected to the bladder 5. An inflation sensor may include a first sensor element 41, preferably a magnet, attached to the bladder 5, and a second sensor element 42, preferably a reed switch, attached to the housing 29. The inflation sensor may determine the inflation state of the bladder 5. When the inflation sensor determines that the bladder 5 is deflated (e.g., when the first and second sensor elements are separated by a distance sufficient to result in minimal magnetic force therebetween), the air compressor 28 is preferably turned on to inflate the bladder 5. When the inflation sensor determines that the bladder 5 is inflated (e.g., when the first and second sensor elements are sufficiently near one another to result in substantial magnetic force therebetween), the air compressor 28 is preferably turned off. The air compressor 28 may be pneumatically controlled with a solenoid module 40 or electrically controlled.

As shown in FIG. 9a, the pump 1 may include a secondary exhaust valve with a material exhaust orifice 16, connected to the material line fitting 26 and the material line 14. The secondary exhaust valve may further include a secondary check ball 19, a seat 20, and a chamber 21, which support the material line fitting 26. This secondary valve may be advantageous where the drywall material or other fluid utilized with the present invention has particles suspended therein that might prevent the valve member from seating properly in the orifice. The inclusion of a secondary valve thus provides an added protection against undesirable backflow of material.

The set of tools that may be used with the pump 1 includes drywall mud, tape, and texture application and finishing devices. Each tool preferably connects to the material line 14 and the control line 15. Referring to FIGS. 19a-19e, a universal hose/tool fitting part 900 may be used with the tools, where appropriate. The universal fitting part 900 is preferably made using an injection molding process. The universal fitting part 900 may form part of the handle, the material line fitting 901, the control line fitting 902, a high pressure air fitting 904 and the control line orifice 903 on a wand tool 300, a mud knife tool 400, a mud bead tool 500, a wall texture spray tool 600, and an acoustic texture spray tool 700.

As shown in FIGS. 10a and 10b, the tape applicator tool 200 may be used to hold, cut, and apply drywall tape and mud. The tool 200 preferably connects to the material line 14 and control line 15 via fittings 201 for material and fitting 202 for control air. The tape applicator tool 200 may have a cavity that holds a supply of drywall tape 206 and an area to advance and cut off the tape 204. The tool 200 may also have a material line that feeds the drywall material 32 into a wetting chamber as it flows out of the tool 200 onto the work surface. The tool 200 may further include a base plate 203 to enclose the tool and a set of tape rollers 207. The tape applicator tool 200 may have a metering wheel to retrieve drywall material 32 from the pump 1 according to the distance that the tool 200 is moved along the work surface. As illustrated in FIGS. 11a through 11c, a pneumatic tape cutter 220 may also be added to the tape applicator tool 200 for cutting the drywall tape 204.

Referring to FIGS. 12a and 12b, the wand tool 300 may be used to apply drywall mud to seams. The tool 300 may be a hollow, elongated tool with threads 301 on the distal end, material and control line fittings 307 and 308, and a control button 306. Referring to FIG. 13, a corner tool 320 may be attached to the threaded end 301 of the wand tool 300 via a threaded end 311 of the corner tool 320. The corner tool 320 may be used to deliver drywall material 32 into corners through a hole 310. The corner-shaped blades 309 may finish the corners as the tool 320 is slid back and forth over the corner seam.

Referring to FIGS. 14 and 14b, the mud knife tool 400 may be used for dispensing and dressing coats of mud. The tool 400 may include a broad knife blade 401 and a smaller knife blade 402 mounted next to the broad knife blade 401. The tool may also have a handle 404, material and control line fittings 406 and 407, and a control button 405. The mud valve 403 is preferably activated when the blades 402 and 401 are flexed against the work surface while the trigger 405 is pulled.

As illustrated in FIGS. 15a-15b and 21a-21e, the mud bead tool 500 may be used to measure a distance rolled and to apply a bead of mud for other tools. The tool 500 may include an elongated hollow body 506, material and control line fittings 501 and 502, a control button 505, and a wheel 503 on the distal end of the tool 500 that is rolled upon the work surface. As depicted in FIG. 21c, when the wheel 503 is rolled upon the work surface and the control button 505 is depressed, drywall material 32 preferably flows through the hollow axle 504, through axle material hole 71, and finally out the distal end of mud bead tool 500 through dispensing holes 507. As shown in FIG. 21 d, when axle material hole 71 is not aligned with one of dispensing holes 507, drywall material is preferably not extruded to the exterior surface of the wheel 503. Notably, material may be present on the outer surface of the wheel 503 even at times when it is not being extruded thereto, since this material may have been pumped to the outer surface of the wheel while the holes 71 and 507 were previously aligned.

As depicted in FIG. 21a, when wheel air hole 508 in wheel 503 is momentarily aligned with axle air hole 63 in hollow axle 504, air 65 is preferably released from mud bead tool 500, causing the bladder 5 to at least partially deflate, and drywall material 32 to flow into the pump 1 from the container. However, during periods when wheel air hole 508 and axle air hole 63 are not aligned, air is preferably not released through the end of mud bead tool 500. The resulting effect is periods of pressurization and quick periods of depressurization as the wheel 503 is rolled along a work surface. Thus, when there is but one radial air hole in each of axle 504 and wheel 503, as illustratively depicted in FIGS. 21a and 21b, air may be released only once per revolution of the wheel 503. The number of holes in axle 504 and wheel 503 may be varied, as appropriate for particular applications, though in preferred embodiments there is one axle air hole 63 and one wheel air hole 508. Similarly, multiple material holes 71 may be included in axle 504 in alternate embodiments of the instant invention, though in the preferred embodiment, there is but one material hole 71.

In preferred embodiments employing mud bead tool 500, drywall material 32 and air 65 simultaneously flow through hollow axle 504, however, in such preferred embodiments, the two substances are not mixed together. As depicted in FIG. 21e, hollow axle 504 preferably contains two interior cavities: an air cavity 76 and a material cavity 75. The air cavity 76 is preferably in fluid communication with the control line of tool 500 such that air may flow through the system, from the pump to the wheel air hole 508 or other air release mechanism (e.g., the control button 505 on the handle of the tool 500). Similarly, material cavity 75 is preferably in fluid communication with the material line of mud bead tool 500 such that drywall material 32 may flow through the system, from the pump to a dispensing hole 507.

A tape roll holder 509 that supports a roll of drywall tape 204 may be attached to the mud bead tool 500 to form a tape applicator tool. A pneumatic cutter 320 may also be attached to the mud bead tool 500.

In addition to the tools described above, the pump 1 may be used with tools manufactured by the Ames Tool Company. See FIG. 18a-c To employ these tools, the control line 15 may be replaced with an adapter button 800, and the material line 14 may be replaced with an adapter gooseneck 801 and an adapter box filler part 802.

In an alternative embodiment of the instant invention, as depicted in FIGS. 23-28, a pneumatic pressure relief valve may be included in the drywall taping and texture system as an air release mechanism. The pneumatic pressure relief valve utilizes flip flop pneumatic logic to regularly maintain two states: fully open and fully closed, corresponding to progression from inflated and deflated bladder states, respectively. In preferred embodiments, the transition between the open and closed states of the pneumatic pressure relief valve is fast, owing in part to the valve preferably including a flip flop effect clip 128. This fast, preferably spring-loaded transition may prevent the valve from freezing in a position between its two regular states, open and closed.

The valve core 101 may be affixed to a closing tube or closing rod 109, which is preferably a hollow member that supports the valve core 101 by the valve core rod 107 and holds the valve core 101 in proper alignment within the hollow valve chamber 126. The interior of the valve core 101 is preferably in fluid communication with the atmosphere such that air may pass from the interior of the pump head, through the at least one orifice 104, when the valve co