US3262192A - Apparatus for preparing protected metal sheets - Google Patents

Description

July 26, 1966 VUKOVCAN ET AL 3,262,192

APPARATUS FOR PREPARING PROTECTED METAL SHEETS 2 Sheets-Sheet 1 Filed Aug. 1, 1965 QMSEEQ N INVENTORS R0004 PA! L. VUAOl/CA/V,

0,4100 BAR/P BY DOA/ALD /r. A/acw R. L. vUKovcAN ETAL 3,262,192

2 Sheets-Sheet 2 ZTMEA ATL July 26, 1966 APPARATUS FOR PREPARING PROTECTED METAL SHEETS Filed Aug. 1, 1963 United States Patent "ice 3,262,192 APPARATUS FOR PREPARING PROTECTED METAL SHEETS Rudolph L. Vulrovcan, Ambridge, Donald K. Archer, Pittsburgh, and David Barr, Leetsdale, Pa., assignors to H. H. Robertson Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 1, 1963, Ser. No. 299,326 6 Claims. {(129-200) This invention relates to apparatus for producing a protected metal article, more particularly a protected metal building sheet. Protected metal building sheets have been described in US. patents of Alden W. Coffman 2,073,334, 2,631,641 and 2,764,808, inter alia.

The object of the present invention is to provide improved apparatus for fabricating long lengths of protected metal building sheets efficiently and economically.

In the accompanying drawings:

FIGURE 1 is a cross-sectional view of a typical protected metal article of the type described in the aforementioned U.S. Patents 2,073,334, 2,631,641 and 2,764,- 808;

FIGURE 2 is a schematic illustration of apparatus similar to that shown in the aforementioned US. Patents 2,631,641 and 2,764,808 for preparing protected metal sheets in long coiled strips;

FIGURE 3 is a fragmentary side-elevation illustration of a crown roll in engagement with a molten-coated metal sheet moving through the present processsing sequence;

FIGURE 4 is a cross-section view taken along the line 4-4 of FIGURE 3 showing the crown roll and metal strip in normal relationship;

FIGURE 5 is a fragmentary plan view taken along the line 5--5 of FIGURE 4 showing the crown roll and metal strip in normal relationship;

FIGURE 6 is a cross-section view similar to FIGURE 4 showing the crown roll displaced from its normal position to accommodate displacement tendencies of the metal strip;

FIGURE 7 is a fragmentary plan view similar to FIG- URE 5 showing the crown roll displaced from its normal position to accommodate displacement tendencies of the metal sheet;

FIGURE 8 is a fragmentary perspective illustration of a spring-mounted roller element and its associated measuring means.

Protected metal sheets A protected metal sheet 10 is shown in FIGURE 1, comprising a metal sheet core 11, a coating of adhesive non-corrodible metal 12 and an outer fibrous layer 13. The metal core 11 is formed from iron or steel, from about 14 gauge to about 28 gauge thickness, prefer-ably from about 18 gauge to about 26 gauge thickness. Either cold-rolled or hot-rolled steel sheets are suitable. The non-corrodible adhesive metal coating 12 is preferably zinc, although various zinc alloys are acceptable as well as tin, cadmium, lead or other non-corrodible metals or alloys. The adhesive coating 12 becomes alloyed with the metal core 11 during the fabrication of the protected metal sheet 10.

The adhesive metal coating 12 is afiixed to the metal core 11 usually by a hot dip process wherein a film of molten adhesive coating metal is applied directly to the entire outer surface of the metal core. While the adhesive coating remains molten, the fibrous layers 13 are pressed into the molten adhesive coating whereby the layers become mechanically keyed or anchored to the resulting protected metal sheet 10. The foregoing processing technology is described in the aforementioned US Patent 2,073,334. Subsequently the fibrous layers 13 are impregnated with a resinous or bituminous saturant which pro- 3,262,192 Patented July 26, 1966 vides weather-resistant properties for the resulting building sheet.

Apparatus and methods for continuously producing such protected metal sheets are described in the aforementioned US. Patents 2,631,641 and 2,764,808. These two patents describe a critical feature in the successful fabrication of protected metal sheets, to wit, the transfer of the metal coated sheet from a hot-dip galvanizing bath to a set of opposed bonding rolls where the fibrous coating is pressed against the molten adhesive metal. Generally those patents recommend vertical withdrawal of the metal core sheet from the galvanizing bath followed by vertical passage of the core sheet between horizontally aligned bonding rolls.

According to the present invention, the metal coated sheet is delivered from the hot-dip galvanizing bath over crown roll means and thence slopingly upwardly to vertically aligned bonding rolls.

This delivery attitude differs from the prior art which shows either (a) generally vertical travel of the coated metal sheet between the galvanizing pot and the horizontally aligned bonding rolls (US. 2,764,808 and US. 2,631,641) or (b) a generally horizontal travel of the coated metal sheet prior to entry into the nip of vertically aligned bonding rolls (US. 2,714,246; 2,724,177; 3,077,- 032). It is not contended herein that the mere change in attitude of the sheet delivery constitutes any invention. Nevertheless, those workers in the prior art who have proposed apparatus and methods for continuous strip processing have uniformly proscribed direction changes of the metal strip between application of the molten metal adhesive coating and the nip of the bonding rolls. Providing a direction change of the metal sheet between the galvanizing pot and the nip of the bonding rolls is contrary to the express teachings of the art of continuous fabrication of protected metal.

In the actual fabrication of continuous lengths of protected metal, however, one serious difiiculty has been maintaining alignment of the fibrous layers with the galvanized metal core. Minor changes in alignment of the moving metal core throughout the sequential processing apparatus are magnified as the metal core progresses through the system. The result is misalignment of the metal core at the nip of the bonding rolls whereby one edge portion of the resulting protected metal sheet does not receive a fibrous layer covering.

The present invention presents a solution to the bonding rolls alignment problem in the fabrication of such protected metal sheets.

Typical processing apparatus is presented in FIGURE 2 wherein a coil 19v of metal core sheet 20 is positioned in uncoiling attitude at the entry point of a sequential processing system. The coil 19 preferably comprises a sheet 20 of cold-rolled steel or hot-rolled steel having a thickness from about 18 gauge through about 26 gauge. The metal core sheet 20 is delivered sequentially through a degreasing bath 21, a pickling bath 22, a water rinse bath 23, a galvanizing pot 24, a heating furnace zone 25, a pair of vertically aligned bonding rolls 26a, 26b, additional processing apparatus hereinafter described to a take-up coil 27.

Drive means such as sheet-engaging rollers 29, 30 are provided for the metal core sheet 20 between the coil 19 and the galvanizing pot 24. The rollers 29, 30 may be driven in synchronism by a suitable motive power source such as an electric motor 31.

The galvanizing .bath 24 comprises preferably a container having an inventory of molten heating metal such as lead 32, a supernatant layer of molten flux 33 on one side of a vertical baflie 34 and a supernatant layer of the molten adhesive metal 35 on the other side of the vertical baffle 34. A pair of exit rolls 36 is partly immersed in the molten adhesive metal 35 to regulate the thickness of adhering molten metal on the metal core sheet 20a.

After the metal core sheet 20 leaves the galvanizing pct 24 it is coated with a molten adhesive metal and is identified by the numeral 20a. After the coated metal core sheet 20a passes through the nip of the bonding rolls 26a, 21b, it is coated with fibrous layer 40a, 40b provided from the coils 28a, 28b and is identified by the numeral 20b. After the fibrous coated metal core 20b has become impregnated with weather-resistant saturant, it is identified by the numeral 20c.

Emerging from the galvanizing bath 24 in a generally vertical attitude, the coated metal core sheet 20a turns over a guide roll means such as a crown roll 38 which is mounted within a few feet of the exit rolls 36. Beyond the crown roll 38, the metal core sheet traverses a heated zone 25 wherein the temperature is sufficient to prevent fusion of the molten adhesive metal coating. In a preferred embodiment, heating gas is burned with air within the heating zone 25 and the resulting fumes and combustion products are vented through a flue 39. The coated metal core sheet 2011 passes directly unsupported from the crown roll 38 to the bonding rolls 26a, 26b at an angle of 20 to 60' degrees relative to the horizontal. Sheets of asbestos paper 40a, 40b are withdrawn continuously from the coils 28a, 28b, respectively. The combustible content of the asbestos paper sheets is burned by impingement with flames identified by the arrows 41, 42. The sheets of residual incombustible asbestos paper peripherally engage the bonding rolls 26a, 26b respectively and, as the asbestos passes through the nip of the bonding rolls, the molten adhesive metal coating is substantially concurrently fused and pressed into the interstices of the asbestos sheets to provide a mechanical keying or anchoring of the abestos paper to the metal core sheet. The resultinglaminated sheet structure is identified by the numeral 20b,

Any excess asbestos paper at the side edges of the laminated sheet 20b is removed by means of trimming devices such as abrasive edge trimmer wheels 43 or spirally grooved steel burrs.

The protected metal sheet 20b is subsequently impregnated with a suitable resinous or bituminous saturant contained in a molten bath 45. The impregnated protected metal sheet passes through a pair of grooved impregnating rolls 46 and thence through one or more pair of smooth-surfaced wiping rolls 47. Excess impregnant is collected in a tray 48 beneath the rolls 46, 47 and returned to the molten bath. The coated, smooth-surfaced protected metal sheets may be cooled by passing through water cooled rolls 49 and water sprays 50.

The resultant impregnated protected metal 20c may be turned into -a coil 27 as shown in FIGURE 2 for aging prior to further processing.

The further processing might comprise applying outer coatings of resins, asphalts and the like. The final sheets are cut to desired lengths and rolled or bent into desirable architectural shapes.

With the present method and the present apparatus, the angle of the coated metal sheet 20a as it engages the bonding rolls 26a, 26b is between about 20 and 60 with the horizontal. A tray member 37 is provided beneath the heating zone 25 to collect any dripping molten metal and return it directly into the galvanizing pot 24.

The bottom surface of the coated metal sheet 20a thereby engages the bonding roll 26b prior to the engagement of the upper surface with the bonding roll 26a. We have found that the vertically aligned bonding rolls are not thereby subjected to damage from fused adhesive metal droplets.

The present invention The present invention resides in the region of the processing sequence between the galvanizing pot exit rolls 36 and the bonding rolls 26a, 26b, i.e., that portion of the sequence wherein the metal core sheet 20 is coated with the molten adhesive metal and is identified by the numeral 20a. At the bonding rolls 26a, 26b, two sheets of the asbestos paper 40a, 40b are presented in alignment for receiving therebetween the coated metal core sheet 20a.

Accurate alignment of the metal core sheet 20a is necessary in order to achieve total surface coverage of the fibrous layers. The crown roll 38 is mounted in a controllably adjustable fashion as indicated schematically in FIGURE 3 wherein the crown roll is seen to be mounted in bearing blocks 51 which are mounted in a suitable housing to permit rapid adjustment of the roll axis location both horizontally (the arrows A) and vertically (the arrows B). The crown roll 38 possesses circumferential grooves 53 which serve to distribute the molten metal coating over the undersurface of the metal sheet 20a which contacts the surface of the crown roll 38.

The position of the crown roll 38 determines the presentation of the coated metal sheet 20a at the nip of the bonding rolls 26a, 26b. The crown roll 38 and the coated metal sheet 20a are shown in FIGURES 4 and 5 in their normal relationship, i.e., with the bearing blocks 51 of the crown roll normally disposed so that the axis 52 of the crown roll is horizontal and is normal to the direction of travel of the metal sheet 20a. FIGURE 6 illustrates the relative displacement of the metal sheet 20a on the crown roll 38 as the roll axis 52 is displaced from the horizontal by the angle Likewise FIGURE 7 shows the relative displacement of the sheet 20a and the crown roll 38 as the axis 52 is displaced from normal (relative to the travel of the sheet 2011) by the angle 0.

It will be observed that the crown roll 38 has a greater diameter at its center than at its ends. By remotely regulating the disposition of the bearing blocks 51, an operator may control the presentation attitude of the coated metal sheet 20a at the nip of the bonding rolls 26a, 26b to provide full fibrous layer covering for the metal sheets 20b- However, we have found that the crown roll 38 is effective only when the coated metal core strip 20a is maintained at a predetermined tension as it passes over the crown roll 38. Unless there is a suflicient tension in the metal core sheet 20 where its entire bottom surface engages the crown roll, the operator (of the crown roll) cannot regulate the sheet position. In accordance with this invention, we have found it to be necessary to maintain the sheet tension at a predetermined value between the bonding rolls 26a, 26b and a selected point along the metal core sheet 20 preceding the galvanizing pot 24.

Specifically, the actual tension in the metal sheet 20 is continuously measured at a measuring station 55 which is located prior to the galvanizing pot 24 in the processing sequence. The measuring station 55 also is located subsequent to at least one of the drive rollers 29, 30 in the processing sequence. The measuring station includes means for determining the instantaneous tension of the metal sheet 20 and regulating means 72 for accelerating and decelerating the drive motor 31 according to the deviation of the actual sheet tension from a predetermined value. A controlling means such as an adjustment knob 73 is provided to control the predetermined tension which is to be maintained. Where the measured sheet tension is excessive, the motor means 31 is accelerated to relieve the tension; where the measured tension is insufficient, the drive motor means 31 is decelerated to augment the sheet tension.

Tests have shown that the system operator can regulate the alignment of the metal sheet 20a at the bonding rolls 26a, 26b so long as the tension of the sheet over the crown roll 38 is maintained at a sufiicient value. The precise value, as might be expected, varies somewhat according to the sheet width and sheet thickness. Where the back tension is inadequate, adjustment of the displacement of the crown roll 38 has no significant effect on the presentation of the metal sheet.

A preferred embodiment of the measuring station 55 comprises a resilient-mounted roller assembly as shown in FIGURE 8 wherein the roller 56 is mounted for rotation in journals 57 which are slidably positioned within a frame 58 having generally vertical side members 59 serving as vertical guideways for the journal 57. A compressed spring 60 fits within the frame 58 against a bottom frame member 61 and against the journals 57.

The roller 56 is positioned out of the straight-linetravel-path of the metal sheet so that tension of the metal sheet exerts a force component against the roller 56 in a direction which can be resisted by the compressed spring 60.

An electrical variable control device 62 is rigidly mounted relative to the frame 58. The electrical variable control device might be a saturable reactor or similar device having an electrical property which can be altered in response to a mechanical displacement. A pivoted compound linkage is provided consisting of arms 63, 64 which are joined through a common pin 65. The other end of the arm 63 is pivotally joined to the journal 57 by means of a pin 66. The other end of the arm 64 is pivotally secured to a journal 67 which is fixed relative to the frame 58 and the control device 62. The arm 64 is equipped with a track element 68. The control device 62 has a reciprocal rod member 69 which has a roller 70 at its extended end. The roller 70 engages the track elernent 68.

An electrical impulse conduit 71 extends from the control device 62 to the regulating means 72 (FIG- URE 2).

As the journal 57 moves downwardly within the frame 58 (in response to increased tension of the metal sheet), the linkage arm 64 turns counterclockwise about the fixed journal 67. The track element 68 allows the roller 70 and rod member 69 to extend from the control device 62, thereby changing the electrical property of the control device 62 which is responsive to displacement of the rod member 69.

The altered electrical property of the control device 62 affects the regulating means 72 via the conduit 71 to accelerate the motor 31 (in the assumed case of increased tension of the metal core sheet). Decrease in metal core sheet tension would develop clockwise movement of the arm 64 and retraction of the rod member 69 to result in deceleration of the motor 31.

As the coil 19 becomes totally unwound, the trailing edge of the metal sheet 20 passes sequentially through the present apparatus. When the trailing edge of the sheet 20 passes the last set of drive rolls 29, which are driven by the tension-responsive drive means 31, there is no further means in the system for maintaining tension of the trailing edge portion of the metal sheet 20. Accordingly the trailing edge of each coil 19 will frequently exhibit misalignment of the fibrous layers a, 40b and the coated metal sheet 20a as the tension is released from the metal sheet 20a as the result of the trailing edge passing beyond the rollers 29, 30. This misalignment appears only in the last few feet of each coil 27. The same misalignment has been found to occur frequently when the back tension of the metal sheet 20a is relaxed for any reason during continuous production of protected metal sheets.

If desired, suitable position-locating means may be provided in association with the bonding rolls 26a or 26b or both. Such position-locating means may comprise: mechanical feeler members which engage the side edge of the moving metal sheet 20a; or a light-beam-and-electric-eye combination which senses the location of the side edge of the advancing metal sheet 2001. The positionlocating means is connected through suitable relays and control means to the axis-determining apparatus of the crown roll 38. For example, the precise location of the bearing blocks 51 (FIGURE 3) can be determined automatically in accordance with the instantaneous location of the side edge of the moving metal sheet 20a or 20b as determined by such position-locating means. Thereby the metal sheet 20a is automatically guided over the crown roll 38 to registry with the fibrous sheets 40a, 40b at the nip of the bonding rolls.

Throughout the present specification there has been reference to maintaining a predetermined tension in the metal core sheet between the bonding rolls 26a, 26b and some point preceding the galvanazing pot 24. The exact quantum of tension has not been measured by applicants since the precise quantum has no real significance in the fabrication of protected metal sheets. Moreover the precise required tension has been demonstrated to vary according to the gauge of metal sheets being processed and also has even been shown to vary between successive coils of sheet metal of the same gauge. The flatness or camber of each indivdual coil of sheet metal may vary despite the same nominal gauge thickness of two coils. Hence the quantum of tension required to retain control of the moving sheet may vary.

Operators of the protected metal fabricating apparatus quickly learn the need for tension by observing the depression of the journals 57 (FIGURE 8). Maintaining the journals depressed by one-inch may be satisfactory for one coil. Maintaining the journals 57 depressed by one-and-one-half-inches may be indicated for the succeeding sheet of metal. The precise tension in quantitative terms has never been measured since it has no reproducible utility on practicing this invention.

We claim:

1. In an apparatus for producing a building sheet of the character having a metal core sheet and fibrous layers covering the surfaces of the core sheet and secured there to by thin layers of non-corrodible metal adhesive alloyed to the surfaces of the metal core sheet and keyed to the fibrous layers;

said apparatus comprising in sequence:

metal core sheet uncoiling apparatus, metal core sheet cleaning bath means, a molten bath containing the said metal adhesive, guide roll means engageable with the said metal core sheet, fibrous layer bonding roll means, and building sheet receiving means; said apparatus further including drive means for advancing the said metal core sheet therethrough;

the improvement comprising:

control means for locating the axis of the said guide roll means and means preceding the said molten bath for maintaining the said metal core sheet at predetermined tension when in engagement with the said guide roll means whereby the position of the said metal core sheet relative to the said bonding roll means may be controlled by adjustment of the said guide roll means.

2. The improvement of claim 1 wherein the said means for maintaining tension comprises a tension-measuringdevice engageable with the said metal sheet and connected in speed regulating relation with the said drive means whereby the speed of the said drive means is regulated inversely to the deviation of tension from a predeter mined value.

3. The improvement of claim 1 wherein the said guide roll means comprises a crown roll which is maintained in contact with the bottom surface of the said metal core sheet.

4. The improvement of claim 3 wherein the said crown roll has circumferential surface grooves.

5. The improvement of claim 1 including positionlocating means associated with the said bonding roll means for determining the position of the said metal core sheet between the said guide roll means and the said bonding roll means,

the said position-locating means being connected to the said guide roll means in axis-locating relation whereby the said axis of the said guide roll means may 7 be located automatically to maintain the position of the said metal core sheet substantially constant at the said bonding roll means.

6. In an apparatus for producing a building sheet of the character having a metal core sheet and fibrous layers covering the surfaces of the core sheet and secured thereto by thin layers of non-corrodible metal adhesive alloyed to the surfaces of the metal core sheet and keyed to the fibrous layers;

said apparatus comprising in sequence:

means for uncoiling a coil of metal core sheet, coating means for applying a molten adhesive to the said metal core sheet, compressive roll mean for bonding fibrous layers to the said metal core sheet and for fusing the said molten adhesive;

the improvement comprising:

control means for maintaining the said metal core sheet at a predetermined tension between the said compressive roll means and a selected point along the metal core sheet preceding the said coating means.

References Cited by the Examiner UNITED STATES PATENTS Eichmann 228-28 Ruhr 228-41 Coffman 156313 X Michel 24275.51 X Michel 7218 Nashley 156164 Bendz 24275.51 X Snyder 24275.51 Coffman 29200 Franzmann 24275 Daniels et a1 24275.51 Steckel et al 156164 Hubbell 29-473.1 Cotrman et a1. 29472.9 Lorig 29407 Cotfman 29473.1

JOHN F. CAMPBELL, Primary Examiner.

WHITMORE A. WILTZ, Examiner.

THOMAS H. EAGER, C. T. MOON,

Assistant Examiners.

Claims (1)

1. IN AN APPARATUS FOR PRODUCING A BULIDING SHEET OF THE CHARACTER HAVING A METAL CORE SHEET AND FIBROUS LAYERS COVERING THE SURFACES OF THE CORE SHEET AND SECURED THERETO BY THIN LAYERS OF NON-CORRODIBLE METAL ADHESIVE ALLOYED TO THE SURFACES OF THE METAL CORE SHEET AND KEYED TO THE FIBROUS LAYERS; SAID APPARATUS COMPRISING IN SEQUENCE: METAL CORE SHEET UNCOILING APPARATUS, METAL CORE SHEET CLEANING BATH MEANS, A MOLTEN BATH CONTAINING THE SAID METAL ADHESIVE, GUIDE ROLL MEANS ENGAGEABLE WITH THE SAID METAL CORE SHEET, FIBROUS LAYER BONDING ROLL MEANS, AND BUILDING SHEET RECEIVING MEANS; SAID APPARATUS FURTHER INCLUDING DRIVE MEANS FOR ADVANCING THE SAID METAL CORE SHEET THERETHROUGH; THE IMPROVEMENT COMPRISING:

Images