US677022A - Manufacture of polished sheet metal. - Google Patents

Description

l Patented lune 25,` |90I. Y A. J. DEMMLER. IIANUFACTURE 0F POLISHED SHEET METAL.

(Application med Aug. 4, 1900.)

No Model.)

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Q q @a UN rTEn STATES PATENT OEEicE.

ALBERT J. DEMMLER, OF VELLSVILLE, OHIO.

MANUFACTURE OF POLISHED SHEET METAL.

SPECIFICATION .forming part of Letters Patent No. 677,022, dated June 25, 1901.

Application filed August 4, 1900. Serial No. 25,856. (No specimens.)

To all whom it 71mg/ concern:

Be it known that I, ALBERT J. DEMMLEE, a resident of Vellsville, in the county of Oolumbiana and State of Ohio, have invented a new and useful Improvement in the Manufacture of Polished Sheet Metal; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to the manufacture of polished sheet metal, and more particularly to the manufacture of polished sheet iron or steel, within which term I of course include thin plate metal, its object being to provide a rapid and efcient method of making the same, so as to increase the output and obtain a greater proportion of good or more evenly iinished sheets.

The process generally practiced in the manufacture of what is known as blued or polished sheet iron or steel is set forth in Letters Patent No. 608,432, granted to iVilliarn M. Theobald August 2, 1898, and has been to raise the same to a heat practically the saine as the ordinary annealing temperature without contact with the atmosphere and at a certain temperature expose the sheets to the atmosphere, each sheet being exposed by turning it over from the pile of sheets as heated onto a truck until the truck contained about one hundred sheets, when it was taken to the polishingrolls, between which the sheets `were passed one or two ata time. This process, while being the best developed for forming blued or polished sheet-iron, was slow and in addition to that had the objection that in turning over the sheets to expose them itwas difficult to bring the edges of the sheets into exact line, so that the extreme edges of the sheets where they extended beyond those in contact therewith were liable to be oxidized to greater extent than the bodies of the sheets, while in so turning over the sheets it Was practically impossible to make them lie so close to each other that the air would not penetrate into the pile,and parts of the sheets would therefore be overoxidized. Another difficulty found was that the sheets first placed upon the truck in exposing them for oxidizing were the last fed to the rolls and were liable to be too cool for proper polishing and fastening the oXid to the bodies of the sheets. By the present invention these difficulties are overcome and more uniformly finished sheets are produced, While the output is increased tWenty-ivetQ) to fifty (50) per cent.

and the percentage of good sheets also largely increased.

In the practice of the invention I heat the sheet metal in bulk and carry the sheet metal in bulk as heated from the annealing or other suitable furnace to the rolls, for this purpose preferably interposing in the charge of sheets in the annealing box or furnace a number of supporting-slabs by which the piles can be handled in bulk, and I feed the sheets from such pile directly to the finishing-rolls, the particular advantages of the invention,as well as the other steps thereof, being hereinafter more particularly set forth. I

To enable others skilled in the art to practice my invention, I will describe the same more fully, referring to the accompanying drawings, in which- Figure lis a side View, partly broken away, of an annealing-box, showing the sheets supported in bulk therein, the overhead grapple arranged to carry the same to the rolls, and the i rolls themselves, with the sheets, supported in front thereof. Fig. 2 is a cross-section of a heating-furnace containing the annealingbox and illustrating tlie manner in which the sheets are built up therein. Fig. 3 is a cross-section of another form of annealingbox. Fig. et is a cross-section of a mufliefurnace suitable for heating the sheet metal in bulk, and Fig. 5 is an end view of the hotbed of Fig. l with the supporting-slab resting thereon.

In the practice of my invention I may employ any suitable furnace for heating the sheets and preparing them for the other steps of the method, either inclosing them in a .suitable box, generally termed an annealing-box, or heating them Within a muffle-furnace, such as shown in Fig. 4. I prefer to heat the sheets in anuealingboxes and have illustrated for that purpose two different kinds of boxes. The ordinary annealing-box (shown in Fig. 2) has the bottom 2 supported on balls 3 and the coveriresting on the bottom and inclosing the sheets to be heated. This box is inserted in a suitable furnace, which is illustrated diagrammatically in the drawings at 5, the gases entering through the flues (5 at each side of the annealing-box. For ease in handling the sheets in bulk as heated I support them upon slabs, using for that purpose the bottom slab 7, which has at ICO its outery edges the upwardly-turning anges 8, with the lifting-lips 9,while within the body of sheets are interposed the lifting-slabs 10 ll l2. I prefer to form these slabs of caststeel, the slabs being made of sufficient thickness to insure support of the body of plates thereon even when the slabs are highly heated. In Fig. 3 I have illustrated another form of annealing-box composed of a series of sections 13, 14, and 15, supported one above the other in such way that the sheets in any section of the stack can be separately exposed, while the bottom 16 of each section acts as a supporting-slab for carrying the pile of sheets to the rolls. In either case where a single box or sectional box is employed to prevent entrance of air to the sheets the joints of the boxes are suitably luted with sand, as at 17. The particular improvements, including the interposed slabs in the ordinary box and the sectional boxes, are set forth in companion applications of even date, Serial Nos. 25,853 and 25,854, and therefore will not require any further description.

In Fig. 4I have illustrated the ordinary muffle-furnaee for the heating of the sheet metal in bulk, this furnace having the side walls 18, roof 19, and fines 2O and having supported therein the muffie-chamber 2l, in which the metal is inserted in bulk, such as when resting upon the slabs 22, and by which it can be inserted within and withdrawn from the munie-chamber by any suitable means, it of course being understood that during the heat- `ing of the sheet metal the munie-chamber is to be closed and luted to prevent overcontact with the atmosphere.

In order to handle the different piles of sheets, I mayemploy any suitable derrick or transferring apparatus, that particularly illustrated in the drawings being suitable for the handling of the sheets when in the annealing-boxes and having grapples 23, provided With toes 24, which pass under the supporting-slabs and lift the same, these grapples running on an overhead track 25 and being adapted to carry the piles of sheets in bulk as heated from the annealing-boxes to the rolls, and for the purpose of lifting the covers from the annealing-boxes the grapples may carry links 26. The rolls employed are usually the two-high finishingrolls, such as used in the ordinary sheet-mill, the rolls being shown at 27 and 28, while in front of the same are the supports 29, on which the slabs supporting the pile of sheets `rest, while ou the opposite side of the rolls I of course employ any suitable supports 30 to receive the sheets as they are delivered therefrom. I also prefer to employ in connection with the rolls an air-blast playing upon the center of the rolls during the rolling of the sheet metal, as described in Letters Patent No. 626,847, granted to IVilliam M. Theobald June 13, 1899, as shown at 3l, the air being control-led by a suitable valve 32, so that the current of air can be regulated to maintain the rolls of even diameter and to aid inthe oxidizing of the under faces of the sheets. The slabs on which the sheets are carried in bulk to the rolls are of course raised to a high heat within the annealing box or furnace, and they act as hot beds to maintain the heat of the sheets in the lower part of the pile during the rolling operation, as described in a companion application, Serial No. 25,853. Any suitable kind of hot bed may be employed for this purpose.

In employing the invention in the manufacture of what is known as bluedi or polished sheet iron or steel I generally proceed as follows: The sheets or thin plates as they are received from the rolling-mill, and preferably Without any previous cleaning by acid or like means, (though of course such cleaning may be employed, if desired,) are first piled in any suitable way to be inserted within the furnace, being either piled in the annealingbox, as illustrated in Figs. 1, 2, and 3, or piled upon slabs which are inserted in the mufflefurnace, as shown in Fig. at. As the sheets are piled when cold, it is preferred to bring the edges of the different piles even, so as to prevent overexposure of the edges of the sheets, and as the sheets remain in such position until they are fed to the rolls the difficulty of the overexposure of the edges of some of the sheets is overcome. The thickness or height of the pile of sheets will depend upon the thickness of the sheetsand the rapidity with which they can be fed to the rolls, the piles generally varying in height from six to fifteen inches and containing from one hundred to five hundred sheets. After the sheets are inserted in the furnace, either within the annealing box or mufiie, the furnace is gradually raised to a sufficient heat to heatthe mass of sheets throughout to a point several hundred degrees higher than that at whichit is desired vto roll the samethat is, the heat is maintained until the mass of sheets in the furnace is soaked throughout, and thereby brought to a sufficient heat to permit the inevitable cooling during the handling and yet not lower the temperature of the sheets below what is termed a warm heat when passing through the rolls. lVhen raised to the proper temperature, which on account of the slow heating considered proper requires from six to twelve hours, the furnace may either be permitted to cool down or the boxes containing the sheets removed therefrom, it being preferred that the sheets shall not be exposed to the atmosphere at a higher temperature than a scarcely visible red heat, which might be roughly stated at about 1,000 Fahrenheit, more or less. Vhere the sheets have been heated in the ordinary box, as soon as they are uncovered, by means of the grapple engaging with one of the interposed slabs, a pile is carried from the box to the rolls in bulk as it has been heated, it being preferred to have a number of sets of rolls, so that the several piles can be immediately carried to IOO IIO

the rolls for finishing, though if that is not practicable the cover of the annealing-box can be replaced. Where the sectional annealing-boxes are used, one section can be withdrawn at a time and carried to and uncovered in front of the rolls, and where the sheets are supported on the slabs in the multle-furnace separate slabs, each supporting a pile, can be removed and carried to the rolls. The sheets are then withdrawn from the piles in front of the rolls and passed between the rolls at a temperature suitable for both oxidation and for the fastening of the oXid to the sheets. This temperature should not be under about 300D. As the edges of the piles are made even before heating and during the heating of the piles, the weight thereof forces the sheets into closer contact, the difficulty of overexposure of the bodies or of the edges is overcome, and the proper oxidation or bluing in the bodies and close to the edges is obtained. As one sheet is withdrawn from the pile its under surface is for the first time exposed to the atmosphere; but it is found that in so working a sufficient exposure is obtained to produce the desired color or iinish, the air-blast from the pipe 3l for maintaining the rolls of even diameter apparently aiding in giving the proper color and finish to the lower face of the sheet. Before the withdrawal of such sheet from the pile the top face of the next sheet is exposed for oxidizing, and the sheets are so fed to the rolls until the pile of sheets supported on the slab has all been rolled. The sheets may be rolled two at a time, if desired, where polish is only desired on one face of the sheet. During such rolling` operation on account of the heat of the hot-bed or slab on which the bulk of sheets rests it is evident that the heat of the sheets in the lower part of the pile is maintained on account of the heat stored in the hot bed, it being found that in so working the lower sheets obtain practically as perfect a bluing and finishing as those in the upper part of the pile and are maintained at a sufficiently high heat for such purpose.

Practical use of the invention shows that almost all the sheets in the pile are finished of first quality, the proportion of Iirst quality sheets obtained being generally over ninety per cent., the sheets produced being of fairly even color throughout, though of course one sheet may vary from another sheet in shade, The labor in manufacture is also materially reduced, as the only-handling of the sheets after heating is the carrying of the same by the transfer device to the rolls and the feeding of the sheets from such pile into the rolls. In addition to this, as two or more sets of rolls may be employed and a pile of sheets carried to each set of rolls, the sheets heated at one time in any suitable box or furnace can be rolled and iinished much closer to the best heat for finishing, while the output of the plant may be very materially increased.

Vhile I have described the invention as especially applicable to the manufacture of blued or polished sheet iron or steel, it isevident that it has advantages in the manufacture of different classes of sheet metal, including sheet copper, brass, dac., and I desire to include the same within my invention.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The method of making sheet metal, consisting in heating a pile of sheets in bulk, carrying the sheets in bulk as heated to the rolls and lifting the heated sheets from the pile and passing them between the rolls.

2. The method of making sheet metal, consisting in heating a pile of sheets, carrying the sheets in bulk as heated to the rolls, supporting them in bulk on a hot bed in position for feeding to the rolls and lifting the sheets from the pile and passing them between the rolls.

3. The method of making blued or polished sheet iron or steel, consisting in heating a pile of sheets when protected from the atmosphere, carrying the sheets in bulk as heated to the rolls and while said sheets are still heated, lifting them from the pile and passing them sheet by sheet between the rolls.

4. The method of making blued or polished sheet iron or steel, consisting in heating a pile of sheets when protected from the atmosphere, carrying the sheets in bulk as heated to the rolls and While said sheets are still heated, lifting them from the pile and pass- IOO ing them sheet by sheet between the rolls and projecting air upon the under faces of the sheets when passing to the rolls.

5. The method of making blued or polished sheet iron or steel, consisting in heating a pile of sheets when protected from the atmosphere, carrying the sheets in bulk as heated to the rolls and supporting them in bulk on a hot bed and lifting the sheets from the pile and passing them between rolls.

6. The method of making blued or polished sheet iron or steel, consisting in inclosing a pile of sheets within an annealing-box, heating them in bulk when inclosed therein, carrying the sheets in bulk as heated to the rolls and lifting them from the pile and passing them sheet by sheet between the rolls.

7. The method of making blued or polished sheet iron or steel, consisting in inclosing a pile of sheets within an annealing-box, heating them in bulk and carrying the sheets in bulk as heated and when inclosed in such box to the rolls, opening the box, and lifting the sheets from the pile and passing them between the rolls.

In testimony whereof I, the said ALBERT J. DEMMLER, have hereunto set my hand.

ALBERT J. DEMMLER.

Witnesses:

JAMEs I. KAY, J. D. BUCKLES?.

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