US2272368A - Method of and apparatus for lubricating sheet metal - Google Patents

Description

J. DUFFY Feb. 10, 1942.

METHOD OF AND'APPARATUS FOR LUBRICATING SHEET METAL 4 Sheets-Shet 1 Filed May 25, 1939 Feb. 10,1942. J. DUFFY 2,272,368

METHOD OF AND APPARATUS FOR LUBRICATING SHEET METAL Filed May 25, 1939 4 Sheets-Sheet 5 J. DUFFY Feb. 10, 1942.

METHOD OF AND APPARATUS FOR LUBRICATING'SHEET METAL 4 Sheets-Sheet 4 Filed May 25, 1939 I I'l PatentedFeb. 10, 1942 ME'rnon or AND APPARATUS FOR LUBRIOATING snaa'r METAL .loseph Dufl'y, Baltimore, Md., assignor to Crown Cork & Seal Company, Inc., Baltimore; Md., a corporation of New York Application May 25, 1939, Serial No. 275,740

17 Claims.

The present invention relates to methods of and mechanisms for lubricating sheet metal-in a cold rolling mill, such as a cold reduction strip mill.

It is an object of the invention to provide, on the strip travelling through the mill, a continuous film of lubricant such as palm oil, of uniform thickness, characterized by the absence of excess oil over certain areas and insufficient oil over other areas.

It is a further object of the invention to provide accurate means for controlling the amount of oil applied to the strip, in order that a con-. tinuous, uniform film or coating of oil of desired thickness may be maintained on both surfaces of the strip, regardless of the speed of travel of the strip through the mill, resulting from varying amounts of reduction effected by the mill.

It is a further object of the invention to provide means for applying lubricant to the surfaces of the strip at a plurality of points during the travel of the strip through the reduction mill, and to provide means for controlling the amount of oil applied at each point, the amount of oil applied at each point being determined by and regulated to correspond to the speed of travel of the strip past each'point. As the strip'is passed through successive reduction rolls, its thickness is decreased and its longitudinal speed of travel correspondingly increased. The present invention provides control means for applying an increased volume of oil to the surfaces of the strip at successive points during its longitudinal travel through the machine to compensate for the increased area of the strip and its increased rate of travel. As a result of the novel means for and method of applying the oil, and the control means therefor, a predetermined volume of oil is applied to each square foot of strip surfaces, and the amount of oil applied to each ton of rolled strip may be accurately determined.

It is a further object of the invention to provide an improved lubricant applying method and apparatus which entirely eliminates spalled rolls in the reduction mill andwhich prevents scarring of the strip being reduced. As a result of the present invention, the life of the reduction rolls and of the backing-up rolls is increased tremendously, and the roll cost in a coldreduction mill is reduced to a small fraction of the cost when prior lubricating methods are used.

Another object of the present invention is to reduce the frictional resistance to the passage of the strip through the'reduction rolls by providing an effective lubricant film or coating for the strip and the rolls. By theuse of the present method and apparatus, in actual practice,

the electric power consumption in the operation reduction strip mill by sprays, atomizers, and the' like, but it has been found impossible to produce the desired uniformity and continuity of film thickness, probably because of the cooling effect of the air during the spraying operation and to the overlapping areas of the fields of the various spray nozzles. 1 A

One of the principal advantages of the present invention results from the fact that, due to the uniformityof film thickness, the amount of palm oil used perton of rolled strip is more than out in half. In accordance with prior spraying methods, nine pounds of palm oil 'per ton of; rolled stock were used, and even then, unsatisfactory results were accomplished, in that spalled rolls were frequent and scarred stock not-uncommon. accordance with the present invention, the

consumption of palm oil has been reduced to 4.2 pounds per ton of rolled stock, and the results have been entirely satisfactory. Since palm oil is expensive, and since no satisfactory cheap substitute has yet been found, this saving is a material item in reducing the cost of rolling strip steel. It is a further object of'the invention to provide means for rolling palm oil onto the surface of the travelling strip in areas where the oil will embodiment of the invention is illustrated, in

connection with a five-stand, four-high cold reductlon mill, but it must be understood that the invention is not limited to the details of construction shown, nor to a mill of this particular type, but includes all devices and method steps coming within the scope of the appended claims, and their equivalents, In the drawings: Figure 1 is a ditic side view of a fivestand, four-high cold reductlonmilL-showing,

roll 25 and over a lower tension-roll 21.

diagrammatically, a preferred arrangement lubricant applying means.

Figure 2 is a side elevation of one roll stand,

showing one set of tensionfrolls and lubricant applying rolls.

Figure 3 is an enlarged vertical section.

and partly in section, taken on line l0-l0 of Figure 4, and

Figure 11 is a detail plan view, looking along line li-ll of Figure 4.

Referringto Figure 1, a strip of. sheet steel I5 is drawn through the mill from left to right, past the first pair of reduction rolls [6-41 having backing-up rolls l6-ll, respectively. The strip steel stock, known in the art as pickled hot bands," are between .072 and .074 inch thick,

and, as they come from the hot rolling mill and 0 before they are delivered to the cold reduction strip mill, they are coated with a heavy film of palm oil, to act as a preservative and to facilitate the subsequent reduction operation. Hence, it is .,unnecessary' to apply additional oil to the strip before it passes through the first two stands of reduction rolls. The strip, during its passage through the cold reduction mill, isreduced bythe action of the stands of rolls, |8 |9, -2l, 2223, 24-25, having backing-up rolls indicated by corresponding primed reference characters. Between the first pair of stands l6|1 and Il-ll, the strip passes beneath an upper tension Similar tension rolls 28-29, 3ll-3l and 32-33 are disposed between the succeeding pairs of stands and the strip passes over a final roll 34, before being wound on the reel 35.

The stock, during its passage through the mill, is reduced from its original thickness of .072"-0.74", to any desired thickness, ranging between .0059 and .010 inch, depending upon the pressure applied between the reduction rolls andthe tension applied to the strip by the tension rolls. This reduction in strip thickness, of

. course, results in a corresponding increase in the length of the strip. The palm oil initially applied to the pickled hot band obviously is not sumcient to maintain a continuous, uniform film over the entire surfacearea of the lengthened strip, and the present invention serves to apply, additional palm oil to the strip during its passage through the mill, to replace the oil used in the reduction process and to supplyadditional 011 to compensate for the elongation of the strip and the increase in its surface area.

The reduction of the thickness of the strip also results in the generation of a tremendo amount of heat, and, in order to maintainithe rolls and the strip at the desired relatively low tempera-- I form of a plurality of water sprays, positioned on the infeed side of each stand. As indicated at 36, 36', water delivery pipes are arranged above and below the bight of the first reduction rolls lB-i'l, so as to direct heavy streams of water on strip on the-discharge side of each stand, but.

these sprays, if used at all, deliver a smaller volume of water than the sprays on the infeed side.

As stated above, sufficient palm oil is applied to the strip, before it is fed into the machine,,to lubricate the strip and the first two stands of rolls |8l1 and ll--l9. After the strip has passed through the second stand, however, its speed of movement has more than doubled as compared to its speed through the first stand. Also, the water sprays l5', 3l' will have washed off a substantial pro rtion of the palm oil initially applied to the lower surface of the strip. Hence, it is advisable to apply an additional coating of oil to that surface, although actual practice has shown that, in normal operation, willcient oil remains on the upper surface of the strip so that additional oil need'not be applied thereto. By the mechanism described in detail hereinafter, the oil is applied to the lower tension roll 25, by a palm oil applicator roll 46, for transfer by the tension rollto the strip.

Between the third and fourth stands, since the striphas been still further reduced in thickness and increased in length, palm oil is applied to the upper and lower surfaces, by ,applicator rolls 41, 48, the oil being transferred to the strip by the tension rolls 30, 3!. Similar applicator rolls 49, apply oil to the tension rolls 32, 33 between the fourth and fifth stands.

As indicated in Figures 2, 3 and 4, each lower tension rolls 21, 39, 3| and 33 is Journalled for rotation in bearings 5| mounted on opposite sides of the outer end of a bell crank lever bracket 52, pivoted at 53 in the stand frame and having its lower end 54 connected through a link 55 to a lever 58 having a weight 51 on its opposite end. As indicated in Figure 2, the point of connection between-the link 55 and the lever 58 may be adjusted between any one of the holes 58, 58a, 58b. Moreover, the fulcrum 59 may be shifted to any one of a plurality of positions, as indicated by the dotted circles in Figure 2. Thus, the upward force applied to the roll 29, and the tension on the strip may be varied at will.

Since each lower lubricant applicator roll is preferably mounted by similar means, a description of the roll 48 will suffice for all. A pair of journal brackets 80 are pivoted at their lower ends at 6| upon the outer ends of links 62 secured upon opposite sides of the upper end of the bell crank bracket 52. At its opposite end each journal bracket is bored to receive a bolt 63, screwed into the bearing cap 5| and having a nut 64 engaging the outer end of a compression spring 65, seated in the bracket and urging the roll 48 upwardly into contact with the tension roll 4|. As indicated inFigure 4, the roll MI, is mounted upon a shaft 66 journalled in anti-friction bearings M in the bracket fill. Thus the lubricant applicator roll 48 is maintained in contact with tension roll 3| under predetermined,

degree, as indicated by the pressure gauge H2,

- guided in brackets 12, likewise fixed to that frame.

The roll 41'preferably rests upon the roll 30 by its own weight, and as indicated in Figure 10, the shaft H is substantially free to rise and fall in the bracket 12, to compensate for slight irregularities in the surface of either roll.

The structure of the applicator rolls per se and the means for delivering oil to their peripheries will now be described, reference being had to Figures 8.

The lower lubricant roll 48 preferably comprises an aluminum roll body 15, cast or otherwise fixed on the shaft 66 and having bored therein two sets of four radial passages '16, 11, communicating at their inner ends with a longitudinal, axial bore 80 in the shaft 66. At their outer ends, the passages 15, 1.1 are tappedand thread and provided with plugs 8|, having reduced apertures 82 of predetermined accurate size. The roll body 15 is covered on its outer surface with a pervious,

porous, absorbent material, preferably standard.

tubular wicking 83, stretched tightly over the roll and secured by wires 84, or the like, at the reduced ends of the roll. axial bore 80 of the shaft 85 by means herein- Oil is delivered to the in communication with the discharge sideof the regulator. The oil flows through agate valve H3 and pipe II4 to and through a solenoid-operated valve H5 and a T-fitting H6, having one branch II1 leading through a flexible conduit II8 to the pipe I03 for the upper roll and, through another branch I I9 and a flexible conduit I20 to the pipe 85 associated with the lower roll. Current'for controlling the operation of the solenoid H5 is delivered through an electrical conduit I2I, -l22 and junction box I23. The current may be controlled by a manually-operated switch positioned at any convenient point, preferably on the rollstand frame. Thus, the several sets of lubricant applicator rolls for the several stands may be independently controlled. f

The amount of oil delivered to the periphery of the respective applicator rolls is determined by the pressure of the oil, as fixed by the pressure regulator III, by the diameter of the apertures 82, IM in the plugs 8|, I00, and by the'speedof rotation of the rolls themselves. If the speed of rotation increases; the centrifugal force on the oil in the radial passages 15, 11, 98, .99 increases, with the result that the pressure on the oil passing through the reduced apertures in the plugs at the ends of the passages is increased and more oil is delivered to the pervious wicking for transfer by the associated tension rolls to the strip travelling through the mill.

Preferably, more oil is delivered to the strip by the applicator rolls 49, than by the precedafter described, through a non-rotatable pipe section 85, projecting axially into one end of the shaft and secured in fluid-tight relation with respect thereto by a stufiing box and packing gland construction represented at 86, Figure 6. A plug 81, closing the other end of the bore 80, may be removed to vent air from the system when it is initially filled with oil, or at subsequenttimes. The upper roll 41 comprises a cast roll body 90, journalled through anti-friction bearings 9I upon the reduced ends 92 ofa shaft or pipe 93 having an axial bore 94 and apertures 95, 96 through its side wall, communicating with an annular space 91 between the outer periphery of the shaft and the inner periphery of the roll body 90. The roll body has two longitudinally spaced sets of four radial passages 98, 99, leading from the aforesaid annular space to the periphery of the roll, where the passages are tapped and threaded to receive plugs I00 having bores "ll of accurate. predetermined diameter. The periphery of the roll body, as in the case of the lower roll, is covered by a pervious tubular layer of wicking material I02, or the like. Oil delivered to the axial bore 94 through a pipe I03 fills the annular space 91 and flows through the radial passages 98, 99 to the periphery, the leakage of oil from the space 91 through the bearings 9| being prevented by stuffing boxes I04 at opposite ends of the roll. At the other end of the-shaft 93, a short pipe section I05 is positioned, having a cap I05 associated therewith, so that air may be vented from the system whenever desired.

ing rolls 41, 48, since, after the fourth stand, the surface area of the strip has been increased and its rate of travel past the tension rolls ha like- ,wise been greatly increased. Similarly, more oil is applied to the strip by the rolls 41, 48 than by the roll 46, since the reduction effected by the third stand, has increased thesurface area over that resulting from the reduction effected by the second stand, as well as the speed of movement of the strip. The progressive increase in the amount of application of palm oil to the strip corresponding upper tension roll, to compensate Referring to Figures 4 and 11, heated palm oil .is delivered to the system through a pipe IIO for the loss of oil from thelower surface of the strip as a result of the washing action of the cooling water. This result is effected by making theapertures 82 associated with the lower roll slightly larger than the corresponding apertures IOI in the plugs I00 carried by-the upper roll- It should be noted that, after the. strip passes through any stand of reduction rolls, it is substantially dry, since no cooling water can be carried through the rolls at the tremendous pressure existing therebetween. The palm oil is thus applied to the dry strip by the tension roll and, since the strip is moving at a high rate of speed, it cannot be substantially washed away by the cooling water sprays for the next stand, since the sprays play primarily upon the reduction rolls. The volume of water delivered by the sprays 4I45 is not sufficient to adversely affect the film of oil on the upper surface of the strip; However, attempts to apply palm oil directly 'to the reduction rolls have met with failure because (a) if the oil is applied on the outfeed side of the stand, it cannot pass through the bight between the reduction roll and the backing-up roll, and (b) if it is applied to the infeed side of the reduction rolls, it is. washed away by the cooling water as rapidly as applied.

In order to illustrate the operation of the present invention, a specific example will be given. A pickled hot band of substantially .074 inch thickness, having a relatively thick coating of substantially solidified palm oil on both of its surfaces, is passed through the reduction rolls I5, I! and through all of the successive stands. When the machine is operating at normal maximum speed, the first pair of reduction rolls, which are 18" in diameter, run at 38.60 revolutions per minute, delivering the strip at a rate of 181.80 feet per minute. The strip is delivered from the second stand at substantially 360.74 feet per minute, as a result of a roll revolution of 76.59 R; P. M. Heated palm oil, at a temperature of between 180 and 212 F., is applied to the applicator roll 46 behind the second stand at a pressure of 2.25 pounds. The rolls of the third stand rotate at a speed of 125.84 R. P. M. and deliver the strip steel at approximately 592.7 feet per minute. Heated palm oil is delivered to the rolls 41, 48 at 2.25 pounds pressure. The reduc tion rolls of the fourth stand rotate at 180.8 R. P. M. and deliver the strip at a speed of 851.56 feet per minute. The palm oil is preferably applied after the fourth stand to the rolls 49, 53 at a pressure of 2.5 pounds. After the final reduction effected by the fifth stand, the sheet is travelling at a speed of 907.7 feet per minute. In the example given, the strip is reduced to a finished thickness of .006".

The increased pressure and the increased rate of rotation of the applicator rolls contribute to deliver a continuous film of substantially uniform thickness to the strip, during its passage through the mill, so that sufficient lubricant is applied to compensate for that used in the reduction operation, and for any oil that may be washed away by the cooling water, and, finally, to compensate for the tremendous elongation of the strip during its reduction.

It will be understood that the examples of speeds and pressures given above are i.lustlat v only and are in no sense restrictive of the invention. The invention is not limited to the spec fic details of construction described above and illus trated in the accompanying drawings, but covers all modifications coming within the scope of the appended claims and their equivalents.

I claim:

1. In a cold reduction strip mill comprising at least two stands of reduction rolls and nonreducing tension rolls for the strip positioned between said stands; means for applying lubricant to the strip, comprising a lubricant applicator roll having its surface in contact with one of said tension rolls, and means for supplying lubricant to the surface of said applicator roll, to be transferred by the tension roll to the surface of said strip.

2. In a cold reduction strip mill comprising reduction rolls and upper and lower tension rolls for the strip positioned in longitudinally spaced apart relation behind the reduction rolls; means for applying lubricant to the upper and lower faces of the strip, comprising a lubricant applicator roll associated with each of said tension rolls and having its surface in contact with the surface of the associated tension roll, and means for supplying lubricant to the surfaces of each of said applicator rolls, for transfer by the tension rolls to the adjacent surfaces of the strip.

3. In a cold reduction strip mill of the class wherein cooling-water is projected upon the reduction rolls at the infeed side of the rolls and wherein tension rolls are positioned at the outieed side thereof; means disposed out of the Working area of the cooling water for applying lubricant to the strip, said means comprising a lubricant applicator roll having its surface in contact with one of said tension rolls, and means for supplying lubricant to the surface of said applicator roll to be transferred by the tension roll to the surface of the strip, whereby the lubricant applied to the strip is not adversely affected by the cooling-water.

4. In a cold reduction strip mill of the type wherein the strip passes through reduction rolls and wherein an upper tension roll is mounted for rotation about a fixed axis and a lower tension roll is spaced longitudinally from the first tension roll and is mounted for vertical movement to vary the tension on the strip; means for applying lubricant to the strip, said means comprising a relatively fixed lubricant applicator roll having its surface in contact with said upper tension roll, a lower lubricant applicator roll mounted for vertical movement with said lower tension roll and having its surface in contact therewith, and means for supplying lubricant to said applicator rolls for transfer by the tension rolls to the surfaces of the strip.

5. A cold reduction strip mill of the class wherein a tension roll for the lower surface of the strip is mounted upon a vertically movable support behind the reduction rolls, characterized by the provision of means for applying lubricant to said strip, said means comprising a lubricant applicator roll carried by said support, means for urging the surface of said applicator roll into contact with the surface of the tension roll, and means for supplying lubricant to the surface of the applicator roll for transfer by the tension roll to the strip.

6. In a cold reduction strip mill of the class wherein tension rolls are mounted between two stands of reduction rolls, means for applying lubricant to the surfaces of the strip, said means comprising a lubricant applicator roll having its surface in contact with one of said tension rolls, said applicator roll having a pervious surface, and means for delivering lubricant from the interior of said roll through said surface to the tension roll, to be transferred thereby to the surface of the strip. 7

7. In a cold reduction strip mill of the class wherein tension rolls are mounted between two stands of reduction rolls, means for applying lubricant to the surfaces of the strip, said means comprising a lubricant applicator roll having its surface in contact with one of said tension rolls, said applicator roll having a porous, absorbent surface and an interiorly disposed lubricant conduit, and means for delivering lubricant under pressure to said conduit and to said surface for transfer by the tension roll to the strip.

8. In a cold reduction strip mill of the class wherein tension rolls are mounted between two stands of reduction rolls, means for applying lubricant to the surfaces of the strip, said means comprising a lubricant applicator roll having its surface in contact with. one of said tension rolls, the surface of said applicator roll being covered with a textile wicking fabric. said roll having'an interiorly disposed lubricant' conduit leading thereto, and means for delivering lubricant under pressureto said conduit and said covering, for transfer by the tension roll to the strip.

9. In a cold reduction strip mill of the class wherein tension rolls are mounted between two' stands of reduction rolls, means for applying lubricant to a surface of the strip comprising a pervious lubricant applicator roll having its surface in contact with one of said tension rolls,

a supply of oil under pressure, a pressure regulator connected thereto, and a conduit leading from said regulator -to the interior of saidpervious roll for delivering lubricant under predetermined pressure to the surface thereof, for transfer by the tension roll to thestrip.

10. In a cold reduction strip mill of the class wherein tension rolls are mounted between two stands of reduction ,rolls, means for applying lubricant to the surfaces of the strip, said means comprising a pair of pervious lubricant applicator rolls having surfaces in contact with the tension rolls above and below the strip, a supply of lubricant under pressure, a pressure regulator connected thereto, a conduit leading therefrom' to the interior of'each of said pervious rolls for delivering lubricant under predetermined pressure to. the surfaces thereof, for transfer-by the tensionrolls to the upper and lower surfaces of the strip. 1 p

11. In a cold reduction strip mill of the class pressure and thereby causing the oil to flow to said pervious surface, transferring the oil from the surface of the applicator roll to the tension ing the oil under predetermined, regulated preswherein tension rolls are mounted between two stands of reduction rolls, means for applying lubricant to the surfaces of the strip, said means comprising a pair of pervious lubricant applicator rolls having surfaces in contact with the tension rolls above and below thestrip, a source of lubricant under pressure, a pressure regulator connected thereto, a conduit leadingtherefrom, a solenoid actuated valve in the conduit, branch conduits leading therefrom to said pervious rolls for delivering oil to the surfaces thereof under predetermined pressure, and electric control -means for actuating said solenoid to cut off the supply of oil to said branch conduits and said a set of tension rolls is disposed between each pair of adjacent stands; means for applying oil to the strip and the reduction rolls, said means comprising sets of pervious applicator rolls disposed between certain pairs of stands in contact with the adjacent "sets of tension rolls, and independent means for delivering oil to each set of applicator rolls, said oil 'delivery means each comprising a pressure regulator, means for delivering oil under pressure thereto, conduit means leading therefrom to the interior of the pervious 'rolls, a solenoid-operated valve in the conduit means, and electrical control means for actuating the solenoid to close the valve.

.13. In the cold reduction of strip steel in a cold reduction strip mill "having a plurality of stands of reduction rolls and tension rolls spaced between the stands, the method of applying lubricant to the strip which comprises positioning an oil applicator roll having a pervious surface in contact with a tension roll for the strip,

delivering oil to the interior of said roll under sure therefrom to and through an applicator roll having a porous surface, transferring the oil from said roll in a uniform film to a tension roll and spreading the oil'upon the travelling strip by transfer from the tension roll to the strip.

15. The method of lubricating strip steel in a cold reduction strip mill having a mummy):

stands of reduction rolls, which comprises rolling a sufficient volume of palm oil upon the surface of the strip travelling at a predetermined speed between a forwardly disposed pair of stands to form a continuous oil film of desired thickness thereon, and rolling progressively increasing vol- -the successive stands due to the reduction in the thickness of the strip. v

16. The method of lubricating strip steel in a cold reduction strip mill having a plurality of stands of reduction rolls, which comprises rolling an amount of oil onto the surface of'the strip between a relatively forwardly disposed pair of rolls, sufiicient to form a continuous, uniform film of oil of desired thickness on the strip travelling therepast at a predetermined relatively slow rate of speed, rolling a greater amount of oil \onto the surface of the strip travelling between the next pair of stands suflioient to form a continuous, uniform film, of' oil of desired thickness on the surface of the strip travelling therepast at an increased rate of speed resulting from the reduction effected by the previous stand, and rolling a still greater amount of oil upon the surface of the strip travelling between the next pair of stands .sufiicient to form a continuous, uniform film of oil on the surface of the strip travelling therepast at a still greater rate of speed. I a

17. The. method of lubricating strip steel in a five-"stand, four-rhigh cold reduction strip mill which comprises rolling a predetermined, relatively small volumeof oil'lipon the undersurface of the strip between the second and third stands, sufficient to form a continuous film of oil thereon corresponding to the relatively slow speed of travel therepast, rolling increased volumes of oil upon the upperand lower surfaces of the strip between the third and fourth stands, to form continuous films of oil on the surfaces of the strip travelling at an increased rate of speed therepast, and rolling increased amounts of oil upon the upper and lower surfaces of the strip between the fourth and fifth stands to maintain therepast --at a still greater rate of speed.

JOSEPH DUFFY.

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