US3397561A - Aluminum wall panel and method of making same - Google Patents

Description

Aug. 20, 1968 D. J. YOUSSI 3,397,561

ALUMINUM WALL PANEL AND METHOD OF MAKING SAME Filed Jan. 7, 1966 P Sheets-Sheet 1 /J J I INVENTOR.

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ALUMINUM WALL PANEL AND METHOD OF MAKING SAME Filed Jan. 7, 1966 2 Sheets-Sheet 2 34 5 7' 36 32 3 J9 'fi l 37 A J2 V V 4" L d I J6fi 52 53 l O/ o o 0 40% o v INVENTOR.

United States Patent O 3,397,561 ALUMINUM WALL PANEL AND METHOD OF MAKING SAME Dale J. Youssi, Dover, Ohio, assignor to Alsco, Inc., Akron, Ohio, a corporation of Delaware Filed Jan. 7, 1966, Ser. No. 519,320 5 Claims. (CI. 72-43) ABSTRACT OF THE DISCLOSURE A method of producing aluminum wall panels which are coated with dielectric material except along longitudinally extending strips. The dielectric free strips are located such that they are in interfacial contact with similar strips on adjacent panels when the panels are installed on a building, thereby establishing electrical connection between all of the panels on the wall of a building. The entire aluminum panel is first treated with an acidic solution containing fluorine bearing compounds and hexavalent chromium to provide an electrically conductive base coating. A dielectric coating is then applied over this base coating with a longitudinal strip left uncoated on each side of the panel. The dielectric free strips are then coated with an electrically conductive lubricating oil thinned with a volatile solvent. The panel thus coated subsequently passes through forming rolls which produce the desired cross section of the panel so that when the panels are installed on a building the oil coated dielectric free strips on adjacent panels are in interfacial contact with one another.

The invention relates to an improved aluminum siding panel of the general type disclosed in the pending application of Marvin R. Collins, Ser. No. 517,178, filed Dec. 8, 1965, now Patent No. 3,318,060, and to an improved method of making such panels.

An aluminum wall panel incorporating the present invention is coated with a dielectric material excepting along longitudinally extending strips which are positioned in interfacial contact with similar strips on adjacent panels when the panels are installed on a building. This interfacial contact between the strips provides an electrical connection between adjacent panels and permits the use of a single ground to effectively ground all of the panels installed upon the building. The dielectric free zone or strips are coated with electrically conductive corrosion resistant coatings, so full corrosion resistance is provided. Referonce may be made to the application cited above for a detailed description of the grounding operation and benefits realized with such panels.

The illustrated embodiment of a panel incorporating the present invention includes a base of sheet aluminum completely coated with a chemical primer coating, preferably of the type known as Alodine coatings, obtained by treating the surface of the aluminum sheet with an acidic solution containing fluorine bearing compounds and hexavalent chromium. One such coating is described in United States Letters Patent to Newhard et al., No. 2,988,465, dated June 13, 1961. Such a chemical primer coating provides substantial corrosion resistance and an excellent base for dielectric corrosion resistant coatings customarily used on aluminum Wall panels.

In order to provide for the electrical connection between adjacent panels the dielectric coating is skip coated, in that a longitudinally extending strip free of dielectric coating is provided adjacent to each longitudinal edge of the panel. The panels are shaped so that each dielectric free strip is placed in interfacial contact with a corresponding strip on an adjacent panel when the panels are installed on a building. These strips are protected against corrosion by the primer coating and a residual oil coating, both of 3,397,561 Patented Aug. 20, 1968 "ice which provide electrical conductivity. Consequently the adjacent panels are electrically connected and a single ground may be used to ground an entire wall array. The

residual oil coating is uniformly thin so that it is substantially non-tacky, does not run or streak and does not adversely affect conductivity. Preferably, the residual coating results from the roller application of a low wax content petroleum oil mixed with a volatile thinner which evaporates after the manufacture of the panels, leaving a uniformly thin protective coating over the chemical primer coating. The oil coating serves two major functions. During the forming operation it provides lubrication to reduce forming roll wear and afterwards it provides corrosion resistance.

In a preferred method of manufacturing panels, according to this invention, elongated aluminum sheet material is passed through coating means which apply the chemical primer coating to all surfaces of the strip. Subsequently, the sheet is passed through means which apply the dielectric coating leaving the required uncoated strips along each edge of the sheet. The dielectric coated sheet is then coated along the dielectric free strips with a lubricating oil and subsequently passes through forming rolls which provide the desired shape for the panels. The strips are then sheared in appropriate length and packed for shipment and installation.

It is an important object of this invention to provide a novel and improved aluminum wall panel including conductive strips which automatically result in an electrical connection between adjacent panels when the panels are installed on a building.

It is another important object of this invention to provide a novel and improved aluminum wall panel, according to the preceding object, wherein dielectric protective coatings are provided to cover the surfaces of the panel excepting along a dielectric free strip substantially adjacent to each longitudinal edge and wherein such dielectric free strip is protected by a conductive coating combination including a chemical primer base coating and a residual oil coating both of which are electrically conductive.

It is still another object of this invention to provide a novel and improved method of forming an aluminum wall panel, according to the preceding objects, wherein the oil coating is roller applied immediately before the forming of the panels.

Further objects and advantages will appear from the following description and drawings wherein:

FIGURE 1 is a perspective view of an aluminum Wall panel incorporating the present invention;

FIGURE 2 is an enlarged fragmentary cross-section illustrating one preferred panel shape and the structure along the area of interfacial contact between the dielectric free conductive strips;

FIGURE 3 is a greatly enlarged fragmentary crosssection illustrating the coating arrangement of the panels;

FIGURE 40 is a schematic of the method of applying the chemical primer base coating;

FIGURE 4b is a schematic illustration of the method of applying the dielectric coating;

FIGURE 40 is a, schematic illustration of the operation of applying the oil coating, the shaping of the panels, and the shearing of the panels from the sheet;

FIGURE 5 is an enlarged fragmentary view of one roller for applying the dielectric coating; and

FIGURE 6 is an enlarged schematic view of the rollers for applying the oil coating to the dielectric free strips on the panel.

FIGURES 1 to 3 illustrate one embodiment of a panel incorporating this invention. This panel is normally installed horizontally on a building structure in such a manner that the lower edge of the panel overlaps and is in electrical interfacial contact with the upper edge of the adjacent panel. Similarly, the upper edgeaof the panel is overlapped by the next panel above and provides interf-acial electrical contact along the joint between the adjacent panels.

The invention may also be incorporated into panels adapted to be oriented in the vertical direction to give a vertical board effect. In such panels it is customary to form a protrusion adjacent to one edge to provide imitation batten strips. However, vertical panels may be identical with horizontal panels if desired.

The panel is bounded along is upper edge portion by a joint section 11 and is provided at its lower edge portion with a complementary joint section 12. When adjacent panels are properly installed the joint sections interlock, as illustrated in FIGURE 2. Each panel 10 has a front face 8 and a rear face 9. The panels are provided with a dielectric corrosive resistant coating which may or may not be the same on the front and back faces of the panels. The dielectric coating 13 on the exterior or front face 8 may comprise a paint or finish which is particularly adapted for exterior exposure and exterior dress of the wall. The dielectric coating 14 on the rear face 9 may be a, paint particularly adapted for interior wall conditions and need not fulfill any decorative or aesthetic function. It will be understood, however, that in some circumstances it may be desirable to employ the same dielectric corrosion resistant coating on both the front and back sides of the panel. In FIGURE 2 the scale of the drawings is greatly exaggerated so that the dielectric coatings 13 and 14 can be illustrated.

In the vicinity of the lower edge 12 of each panel 10 a strip 16 along the rear face 9 is free of dielectric protective coating 14 and is in interfacial contact with a strip 17 of the front face 8- of the lower panel in the vicinity of the upper edge 11 of the lower panel. The portion 17, like the portion 16, is free of dielectric protective coating and together they constitute mating strips extending longitudinally along the edges of the panels. The interfacial contact between the strips 16 and 17 provides an electrical connection between adjacent panels. All parts of the front and back faces 8 and 9, respectively, other than the strips 16 and 17 are covered by one or the other of the coatings 13 and 14. Nail slots may be provided at 18 and drain openings at 19.

Each of the dielectric free strips 16 and 17 is provided with a compound coating, as best illustrated in FIGURE 6. The base metal 21 is coated on its front and back faces with chemical primer coatings 22 and 23, respectively. The dielectric coating 14 extends over the primer coating 23 and the dielectric coating 13 covers the primer coating 22. In the dielectric free strip 16, however, a residual oil coating 24 covers the chemical primer coating 23 and extends over the adjacent edge 26 of the coating 14.

The oil coating 24 is very thin and uniform preferably resulting from the roller application of a mixture of a light petroleum oil of low wax content and a volatile solvent preferably mixed with one part by volume of petroleum oil to five parts by volume of volatile solvent. However, satisfactory results are obtained with mixtures containing one part, by volume, of oil and from four to six parts, by volume, of solvent. One solvent which has been found to function satisfactorily is sold under the trade name Renuzit by Renuzit Home Products Company of Philadelphia, Pennsylvania.

Referring now to FIGURES 4a through 6, one preferred method of forming the panels 10 includes three major steps performed on aluminum stock in elongated sheet form. The first step is illustrated in FIGURE 4a wherein sheet aluminum 31 is fed from a supply roll 32 through a spray assembly 33 and then through an oven 34. After passing through the oven the sheet 31 is rewound on a roll 36. In the coating device the sheet passes over a first roll 37 and second roll 38 which properly locate the sheet and provide tensioning. Subsequently the sheet passes between spray nozzles 39 and 41 which coat the upper and lower sides of the sheet preferably with an acidic solution containing fluorine bearing compounds and hexavalent chromium. The sheet then passes over a second pair of rolls 42 and 43 and on through the oven 34 which heats the coated sheet. If desired, quenching may be provided between the oven 34 and the winding roll 36. The sheet on the roll 36 is thus completely coated on all surfaces with a chemical primer coating.

Subsequently the roll 36 is transferred to the mechanism illustrated in FIGURE 4b which provides the dielectric coatings 13 and 14. The coating mechanism is illustrated generally at 44 and includes rolls 46 and 47 arranged to tension the sheet within the coating mechanism. The sheet 31 passes from the roll 36 over a guide roll 48 around the rolls 46 and 47 and then out of the machine to an oven 49 which bakes the dielectric coating.

After the sheet passes over the roll 47 the lower side of the sheet is engaged by a coating roll 51 provided with a suitable gap to prevent the application of coating along the strip 16. The coating material is applied to the roller 51 by a pickup roller 52 which extends into a coating supply pan 53. The opposite side of the sheet is engaged by a coating roller 54 as it passes over the roller 47. Here again, a supply roller 56 delivers coating material from a supply pan 57 to the roller 54 and the coating roller 54 is provided with means to prevent the application of coating along the strip area 17.

Referring to FIGURE 5, the roller 54 is provided with journal extensions 58 to support it for rotation about its longitudinal axis. The coating surfaces 59 and 61 engage the sheet 31 and a gap 62 is located therebetween so that the coating is not applied to the area of the strip 17. This gap is formed by providing a reduced diameter zone 62 on the roller 54. In the oven 49 the coatings are baked and subsequently the sheet 31 is rolled up at 63. Here again, quenching may be provided to cool the sheet before winding it on the roll 63.

In the final forming operation, illustrated in FIGURE 40, the sheet is removed from the roll 63 and passes between oil coating rolls 64 and 66. The structure of these rolls and their position is best illustrated in FIGURE 6. The roll 64 is journaled for rotation on supports 67 and positioned to engage along its periphery the strip zone 17 overlapping the adjacent edges of the coating 13 to insure full coverage.

Preferably, the rollers 64 and 66 are provided with a felt type surface 68 which absorbs and evenly distributes the oil mixture 69 delivered as drops from supply tubes 71 and 76, respectively. Backup rollers may be provided opposite each of the rollers 64 and 66 to maintain proper engagement between the strip and the associated rollers. Suflicient pressure of engagement is provided between the felt 68 and the associated strips 16 and 17 to insure even distribution of the oil mixture within the felt and to insure that a uniform, thin layer of oil is applied at all points along the strips.

The roll 66 is journaled on roller supports 72 and is proportioned to extend laterally beyond the edge of the sheet 31 as illustrated. The oil mixture 69 is supplied to the lateral projecting portion 73 and is carried by the absorbent qualities of the felt 68 laterally under the sheet 31, so that a uniform coating of oil is applied to the strip 16. A drip pan 74 may be provided to catch any excess.

The tube 76 which delivers the oil 69 to the roller 66 and the tube 71 which delivers the oil to the roller 64 are connected to any suitable metering system which provides adjustment of the rate of oil flow to the respective rollers.

After the sheet 31 passes through the rollers 64 and 66 it .passes through forming rolls 77 which shape the sheet to the desired cross-section. An automatic shear 78 cuts the sheet 31 forming the panels 10 which are then packaged for shipment and installation.

It should be understood that although the sheet is illustrated as rewound between each of the operations illustrated in FIGURES 4a through 40, a continuous process can be utilized. It should also be understood that if desired the panels may be sheared before the coating. The forming of the strip should occur before sub stantial evaporation of the volatile solvent since the oil mixture protects the forming rolls 71 against wear which would otherwise occur if a hard chemical primer base coating were directly exposed to the surface of the rolls. However, the volatile solvent evaporates completely before the installation of the panels on a building, so that the very thin residual coating 24 remaining after the evaporation does not provide any substantial resistance to electrical flow and does not result in tackiness or streaking of the installed panels.

Although a preferred embodiment of this invention is illustrated, it is to be understood that various modifications and rearrangements of parts may be resorted to without departing from the scope of the invention as defined in the following claims.

-I claim:

1. A method of forming dielectric coated aluminum wall panels having longitudinally extending electrically conductive strips comprising passing an elongated sheet of flat aluminum through a primer coating means to apply a chemical primer coating covering both surfaces, thereafter coating both surfaces with a dielectric coating covering said primer coating excepting along a longitudinal strip substantially adjacent to each edge of said sheet, thereafter coating each strip and the surface immediately adjacent thereto with oil by engaging the surface of said primer coating with a roller having an absorbent surface while supplying oil to said roller surface at controlled rates, said oil being thinned with a volatile solvent, and thereafter passing said panels through forming rolls before substantial evaporation of said solvent and shaping said sheet so that it is adapted to overlap a similar sheet with interfacial contact between adjacent strips, said panels being shaped by said forming rolls so that the said strips and the residual oil coating are hidden from view when said wall panels are installed on a building, said primer coating and the residual coating of said oil coating being electrically conductive.

2. A method of forming aluminum Wall panels as set forth in claim 1, wherein one strip is located on the lower side of said sheet at one longitudinal edge when said oil is applied, and the roller coating said one strip projects laterally beyond said one edge, said oil being applied to the projecting portion of said roll and flowing along said roller surface to coat said one strip.

3. A method of forming aluminum wall panels as set forth in claim 1 wherein said roller surface is a felt-like material.

4. A method of forming aluminum wall panels as set forth in claim 3 wherein said oil is applied to said roller sunface as drops.

5. A method of forming aluminum wall panels as set forth in claim 4 wherein said felt-like surface engages said strip with suflicient pressure to insure even distribution of said oil within the body of said felt-like material.

References Cited UNITED STATES PATENTS 2,831,782 4/ 1958 Zvanut 72-42 2,870,737 1/1959 Byrnes 7243 3,233,442 2/ 1966 Zvanut 72-42 3,289,365 12/ 1966 McLaughlin et al 52173 3,318,060 5/1967 Collins 52173 CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner.

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