Watertight joint compound/mud pan and method of manufacture

Abstract

A drywall joint compound or mud pan is constructed as a folded type rectangular container from a single blank of metal. The pan has a flat bottom, and two sidewalls and two end walls that extend upwardly and laterally outward from the bottom. Triangular sections of metal are formed at each corner and folded over an adjacent end wall. Preferably, one sidewall makes a sharp angle with the bottom section and the opposing sidewall has a radius of sufficient size, which will permit the rapid removal of material from said pan.

Description

RELATED APPLICATION

This application claims the benefit of provisional application Ser. No. 60/687,423, filed Jun. 3, 2005.

FIELD OF THE INVENTION

This invention relates to containers or pans used to contain joint compound or mud. A worker, more specifically, a drywall finisher or plasterer, while holding the pan in one hand containing joint compound removes a portion of joint compound and applies the joint compound to a specific surface with a putty knife or taping knife.

BACKGROUND OF THE INVENTION

The use of drywall panels or sheet rock in the construction of interior wall sections is widely known. Joint compound is applied to panel seams to set drywall tape and thereafter so as to render the seam invisible once the sections are painted or prepared for further texturization. During this process a drywall finisher or worker uses a container of sufficient size to hold an amount of joint compound using a putty knife or taping knife to apply joint compound to said joint. The joint compound employed in this process is usually a powder mixed with water or aqueous material or ready-mix available in a variety of sizes. Powdered joint compound material is typically mixed in a larger container and transferred to a joint compound pan. In some cases the joint compound pan is used as the mixing vessel thereby eliminating the need to transfer the material. Ready-mix joint compound is often transferred from a master container, i.e. a five-gallon bucket, to the joint compound pan for application. When setting joint tape, a substantial amount of joint compound is applied to the seam. The tape is then set into the wet joint compound and smoothed with a taping knife to remove excess joint compound and air pockets. This procedure allows for the expanding and contraction of the wallboard panels without developing cracks between the wallboard panels. Drywall screws and nails are also covered with joint compound applied thereto by the knife. It is therefore advantageous to employ the use of a joint compound pan, which allows the rapid removal of a large amount of joint compound. In both cases, whether using a powdered joint compound or ready-mix, the joint compound is often thinned in subsequent applications to seams to render the seams as smooth as possible. When using a thinned joint compound, it is often advantageous to have a sharp angular pan bottom to pinch-off or regulate the amount of compound on the taping knife for subsequent applications.

A variety of joint compound pans have been developed. U.S. Pat. No. 6,575,328 granted to Foraker discloses a joint compound container and insulating pad similar to that show in FIGS. 1 and 2. Foraker does not disclose the way the joint compound pan is constructed other than to say it is a hollow metal pan. A commercially available version of this joint compound pan is a three-piece design wherein the endcaps or end walls are welded to the main body via spot welding or electrical resistance welding. A pan of this design and construction will leak when filled with an aqueous solution as is done to mix or thin joint compound. Second, this type of joint compound pan is more difficult to manufacture because of the three-piece design. Third, the end wall is constructed from a single material thickness usually of a thickness significantly less than the body making the pan weak and flimsy.

U.S. Pat. No. 5,603,428 granted to Breckwoldt discloses to a joint compound pan similar to that shown in FIG. 2. Breckwoldt writes, “The end walls 29 are welded to the bottom wall 19 at opposite ends thereof in conventional fashion.” This can be accomplished one of two ways with respect to welding. First, the endcap can be attached in a fashion similar to that used to make the Foraker pan shown in FIG. 1 of this patent, via simple spotwelds. As previously noted there are leakage problems with this construction. Alternatively, the endcap or end wall can be attached with a continuous mig, tig, or heli-arc weld. FIG. 3 shows a joint compound pan with the continuous weld. The pan shown in FIG. 3 is also available from companies such as Kraft, Stanley and Marshalltown. With this manufacturing technique, a continuous weld is achieved around the periphery of the endcap where it makes contact with the bottom or main body. Although this technique usually achieves a watertight pan, other disadvantages exist. This manufacturing technique is costly. It is widely known in manufacturing circles that welding is a relatively expensive process compared to stamping, forming, and folding.

Another prior art joint compound pan shown in FIG. 4 is manufactured from plastic. While remaining the most economical form of manufacturing, disadvantages exist. Plastic construction lacks the necessary strength required for long-term use in a construction environment. It is easily cracked or chipped when dropped or handled roughly. Therefore, it is rarely considered for the finishing professional. Furthermore, it has a removable steel blade that when positioned into the plastic slot, acts as the straight-edge used to clean the taping knife. This preformed slot often accumulates excess joint compound where it quickly dries. These small dried chunks of joint compound create major problems for the finisher when they are dragged over the seam. Instead of leaving a smooth surface, the dried chunks leave grooves, which need continual smoothing until such grooves disappear.

Edwards et al. in U.S. Pat. No. 6,454,124 disclose a four-piece joint compound pan. Three of the four parts are made from plastic injection molding or similar while the center portion is typically constructed of metal. The endcaps are molded with foot members, which extend below the center portion. While this feature may be handy lifting the pan off of a flat table, it is difficult or nearly impossible to steady the pan on top of a ladder or on a 5 gallon bucket of joint compound. If all four foot members do not contact a flat surface, the joint compound pan rests on the rounded bottom easily tipping over. Furthermore, foot members are easily broken if the pan is dropped thereby rendering the pan useless without all four foot members. For these reasons this pan is both costly and impractical.

It would be highly advantageous, therefore to remedy the foregoing and other deficiencies inherent in prior art. Accordingly, we provide a joint compound pan having one bottom radius between the bottom and one sidewall with sufficient radius to allow the rapid removal of large quantities of joint compound. We further provide a joint compound pan with one sharp angular bottom radius between the bottom and one sidewall to allow the removal of a controlled amount of joint compound. Our pan is watertight to contain a thinned mix of joint compound.

We construct our joint compound pan from a single blank or piece of material, usually metal, with folded corners defining the watertight properties. The folded corner construction significantly increases the strength of the joint compound pan, which is especially useful in rugged construction environments.

Our pan has a triple end wall design which results in a stronger pan, the strength being achieved by folding the material on itself. The present invention is highly impact resistant especially when dropped or resistant to twisting when full of joint compound.

Specific objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description of certain present preferred embodiments thereof shown the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one type of prior art joint compound pan having spot welded endcaps;

FIG. 2 is bottom perspective view of the prior art pan shown in FIG. 1;

FIG. 3 is a top perspective view of another type of prior art joint compound pan with a continuously welded endcap;

FIG. 4 is a top perspective view of yet another type of prior art joint compound pan constructed with plastic;

FIG. 5 is a top perspective view illustrating a present preferred embodiment of our joint compound pan;

FIG. 6 is a top view of a single blank or piece of material used in the construction of the joint compound pan shown in FIG. 5;

FIG. 7 is a perspective view of a partially formed pan of the type shown in FIG. 5; and

FIG. 8 is a perspective view of a second present preferred embodiment of our joint compound pan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is first directed to FIGS. 5 through 8 which illustrate a joint compound pan or mud pan indicated at 10 and constructed in accordance with the teachings of this present invention. Mud pan 10 comprises an open top 11, a bottom 12, sidewalls 13, 15 end walls 17. Sidewall 13 and sidewall 15 generally opposite and diverging upwardly and outwardly from bottom 12 and are joined to end walls 17. As viewed from above, the open top 11 is rectangular in appearance. The bottom 12, end walls 17, and sidewalls 13 and 15 define a volume for containing joint compound or other material therein. Upper edges 22, 14, and 16 define the periphery of opening 11 while the mud pan 10 is accessible through the open top 11. The mud pan 10 is of sufficient length to allow the entry of a drywall taping knife. Openings 11 may be 12″ to 14″ by 4″. The pan is constructed from a suitable material, preferably stainless steel, galvanized steel or other metals and metal alloys which are corrosion resistant and have a minimum thickness 0.022 inches or 26 gauge. We prefer to use 22 gauge steel which has a thickness of from 0.028 inches to 0.030 inches.

Sidewall 13 meets bottom 12 along a corner radius 19 and has a longitudinal upper edge 14. The larger radius 19 is sufficiently large or gradual to permit joint compound to be withdrawn from the mud pan 10 by a natural scooping motion. This radius may vary from about one half inch to one inch. This large radius is especially useful when first applying large amounts of joint compound and tape to seams. Sidewall 15 is joined to bottom 12 with a smaller radius 21 and has a longitudinal upper edge 16. The smaller radius 21, typically one sixteenth inch or less, permits the drywall finisher to pinch-off smaller amounts of joint compound when subsequently thinned layers of joint compound are applied to seams. This is also useful when covering nails or screw holes. When excess joint compound is removed from a seam or nail holes, the excess is scraped over upper edge 14 or 16 and is often reused.

Mud pan 10 is constructed from a single blank 1 or piece of material, preferably configured as shown in FIG. 6. The blank has two long edges 2 and a smaller width. The corners are cut to have two edges 3, 4 that meet at an acute angle. This blank shape will produce a rectangular joint compound pan as shown in FIGS. 5, 7, and 8. By varying the size and shape of the blank shown in FIG. 6, any square or rectangular joint compound pan can be manufactured.

We prefer to place the blank 1 in a cold forming press or on a cold forming die and then bend the sides of the blank to the shape shown in FIG. 7. At this stage of the forming process generally triangular corner sections 18 having overlaying sections of the blank material will extend from each corner of the pan. Radius corners 19 and 21 will have been fully formed. As can be seen in FIG. 7 corner sections 18 prior to folding against end walls 17 are essentially parallel or co-planar with sidewalls 13 and 15. At this point hemmed edges 20 are essentially parallel with bottom 12. Next, the material defining the corner sections 18 is folded over against the outside surface of each end wall 17.

Once corner sections 18 are folded against end walls 17, hemmed edges 20 are folded over to cover the sharp upper edges of corner sections 18 and define the top edge of end walls 17. When corner sections 18 are folded over end walls 17, the corners of the mud pan 10 are comprised of three material thicknesses. This manufacturing method creates an extremely rigid mud pan 10, which is highly resistant to warping and highly impact resistant. Due to the rugged nature of construction environments, this presents a tremendous advantage over all other prior art. Having corner sections 18 extending the full depth of the pan allows mud pan 10 to define a watertight volume. This is especially useful when the mud pan 10 contains liquids or thinned joint compound. Furthermore, the manufacturing method prescribed is more cost effective thereby creating another advantage over other prior art. The unique shape also permits a plurality of mud pans to be stacked or nested for storage, shipping, etc.

We prefer to provide a joint compound pan having a sharp radius 21 on one bottom edge and a gradual radius 19 along the opposite bottom edge as shown in FIGS. 5 and 7. However, the process described with respect to forming the blank shown in FIG. 6 can be used to provide two sharp radii or two gradual radii along the bottom edge. A second present preferred embodiment shown in FIG. 8 has two sharp radii at 21 and 29.

Although we have shown and described certain present preferred embodiments of our joint compound pan and method of making same it should be distinctly understood that our invention is not limited thereto, but may be variously embodied within the scope of the following claims.

Claims

1. A joint compound formed from a blank of a selected material comprising:

a bottom,

a pair of spaced apart sidewalls attached to the bottom, and

a pair of spaced apart end walls attached to the bottom and to the sidewalls, each end wall having an inside surface and an outside surface, a first pair of generally triangular end portions each comprised of two overlapping sections of the material and overlaying the outside surface of one end wall, and a second pair of generally triangular end portions each comprised of two other overlapping sections of the material and overlaying the outside surface of the other end wall.

2. The joint compound pan of claim 1 also comprising a hemmed edge extending from each end wall and folded over the triangular end portions overlaying that end wall.

3. The joint compound pan of claim 1 wherein:

a first radius is formed between the bottom and one of the pair of sidewalls,

a second radius is formed between the bottom and the other one of the pair of sidewalls, and

the first radius is greater than the second radius.

4. The joint compound pan of claim 3 wherein the first radius is between one sixteenth inch and one inch.

5. The joint compound pan of claim 3 wherein the second radius is not greater than one sixteenth inch.

6. The joint compound pan of claim 1 wherein the material is metal.

7. The joint compound pan of claim 6 wherein the material is selected from the group of metals consisting of stainless steel, galvanized steel and corrosion resistant metal alloys.

8. The joint compound pan of claim 1 wherein:

a first radius is formed between the bottom and one of the pair of sidewalls,

a second radius is formed between the bottom and the other one of the pair of sidewalls, and

the first radius and second radius are equal.

9. The joint compound of claim 8 wherein the first radius and the second radius are not greater than one-sixteenth inch.

10. A method of forming a joint compound pan comprising;

selecting a generally rectangular blank having a pair of long edges and a pair of short edges, the blank comprised of a selected material,

folding portions of the blank adjacent each long edge to create a pair of spaced apart sidewalls extending from a bottom and having first radius formed between the bottom and one of the pair of sidewalls and a second radius formed between the bottom and the other one of the pair of sidewalls,

folding portions of the blank adjacent each short edge to create a pair of spaced-apart end walls each end wall having an outside surface,

such that after the sidewalls and the end walls are formed there will be four corners where an end wall meets a side wall, each corner having a generally triangular end portion extending from the corner, each generally triangular end portion comprised of two overlapping sections of the material, and

folding each generally triangular end portion over the outside surface of one of the end walls.

11. The method of claim 10 also comprising folding an edge of each end wall over the generally triangular end portions overlaying that end wall.

12. The method of claim 10 wherein the selected material is selected from stainless steel, galvanized steel and corrosion resistant metal alloys.

13. The method of claim 10 wherein:

a first radius is formed between the bottom and one of the pair of sidewalls,

a second radius is formed between the bottom and the other one of the pair of sidewalls, and

the first radius is greater than the second radius.

14. The method of claim 13 wherein the first radius is between one sixteenth inch and one inch.

15. The method of claim 13 wherein the second radius is not greater than one sixteenth inch.