US1792458A - Rolling mill and method - Google Patents

Description

Feb. l0, 1931. E. BARTEN 1,792,458

ROLLING MILL AND METHOD Filed June, 29, 1929 3 Sheets-Sheet 2 /n ver/far.'

by @l Wa M I5 Sheets-Sheet 5 E. BARTEN ROLLING MILL AND METHOD Filed June 29, 1929 /n ven for TQ/vs T B4 RTE/v Patented Feb. 10, 1931 ERNST BARTEN, F BUSCHEUTTEN, NEAR. SIEGEN, GERMANY ROLLING MILL AND METHOD Application :filed June 29, 1929, Serial No. 374,642, and in Germany May 2, 1925.

My invention relates to rolling mills and to methods of rolling, and has been designed particularly for the rolling of metal blanks of the character of sheets, bands or strips.

The object of my invention is to obtain a very eilicient operation, and to provide an apparatus possessing great advantages as to compactness, flexibility' in operation, and ease of handling the blanks under treatment.

Important advantages are secured, in my invention, by providing special connecting members adapted to be fastened to the ends of the blank, and to move close up to the rolls between which the blank is passed, thereby enabling practically the entire length of the blank to be rolled and to be properly held and guided during such operation. Inl the preferred form of my invention, the said connecting members or connectors are flexible and adapted to wind on drums which are located at each side of said rolls. One en d of each connector is secured to the respective drum, while the other end is provided with a gripper adapted to be fastened to one end of the blank. This feature of my invention enables me to carry out the rolling operation' under much more favorable conditions than when the ends of the blanks are secured to the drums directly; the advantages of this feature are set forth fully in the description following hereinafter. Another feature of my invention ,relates to the provision of a winding device for the 'finished blank, which device is separate from the drums .mentioned above. Other features of the improved rolling mill relate to the mechanism for driving the drums, to presses interposed between the ldrums and the rolls, and to various other de` vices and arrangements the construction and 40 advantages of which are developedA in the detailed descriptionV given below. The new rolling process or method also has a number of valuable novel features, all fullyI explained hereinafter; among these, I will'heremention" 5, '6, of like construction, and to each' drum is brieiy the step yof adjusting the sizeof the' rollinggap while the blank Ais withinsaid* VIV"gap, andiprefera'bly while `theblank is in-lv motion; placing the blank under a much higher longitudinal tension than hitherto, and particularly lunder a tension approaching the elastic limit; in the case where the rolling operation is performed in a succession of passes, reducing from pass to pass the forces roducing the longitudinal tension under w ich the blank is placed; placing the blank portion which is on its way to the rolls under a smaller longitudinal tension than the blank portion which has passed between the rolls; and various other features that are pointed out below, in description and claims.

Reference is to be had to the accompanying drawings illustrating two typical and satisfactory embodiments of rolling mills embodying my present invention. In saiddrawings Fig. l is a longitudinal vertical section through one form of my improved rolling mill; Fig. 2 is a plan view of such rolling mill and its drive; Figs. 3v and 5 are detail elevations of brake mechanism employed in connection `with the drums of the rolling mill; Figs. 4 and 6 are detail elevations of clutch mechanisms used in conjunction with' said drums; Fig. 7 is a plan view showing another form of my rolling mill, in which a different drive is employed.; Fig. 8 is an end elevation of a press which may be associated with the rolling mills of either Fig. 2 or 7 and Fig. 9 is a detail plan View of a.clutchadjusting device which I prefer to employ in connection with the drives shown in Figs. 2 and 7.

In the construction illustrated by Figs. l to 6, A indicates a frame in which are suitably journaled the rolls l, 2, 3, 4, the inner or working rolls 1, 2, which are adapted to engage opposite faces of the blank, being preferably of a smaller diameter than the outer or backing rolls 3, 4. 'Any suitable mechanism (such as, for example, the Wormedriveindicated'at B, operating to shifta slide C vertically) may be employed to' vary the pressure of the rolls, or, in other words, the vertical distance or gap between the blank-engaging rolls 1, '2. At each side of the frame Aarelocateddrumsf secured one end of'a cable, steel-band,or other flexible ymembers 7 and 8 respectively, which might be ofthe same'width. astheblank tobe treated, the other or free ends of these members being provided with yjaws or grippers 9' and 10 respectively, of any suitable construction, for firm connection with the ends of the blank 11 to be rolled, it being understood that this blank is to be passed between the rolls 1, 2. The drums 5, 6 have grooves 12, 13 respectively for the flexible members 7, 8, while recesses 14, respectively are adapted to receive the grippers 9 and 10 Whenever the respective member 7 or 8 has been wound entirely on its drum 5 or 6 respectively, as illustrated in Fig. 1 for the flexible member 8.

Provision is made for driving the drum 5 clockwise, or the drum 6 contraclockwse, so

.that the blank 11 will move toward the right or' toward the left. A suitable arrangement for this purpose is shown in Fig. 2 (with details in Figs. 3, 4, 5, 6, and 9) said Fig. 2 also illustrates a drive for the rolls of frame A, said drive being constructed to enable the r0- tation of said rolls to be reversed. A suitable motor V21, for instance an electric motor, is

connected by a clutch 22 with the shaft 23 carrying a ffy-wheel 24 and a pinion 25. The latter meshes with a larger gear wheel 26 on a shaft 27, which therefore rotates more slowly than the shaft23.

The continuously rotating shaft 27 has two driving connections, one of which is adapted to actuate the rolls of the rolling mill, while the other is adapted to operate the drums 5 and 6. Fig- 2shows the following mechanism or connection for driving the rolls On the shaft 27 are secured rigidly pinions 35, 37 of which the former meshes with a pinion 36, likewise in mesh with a gear wheel 28 mounted loosely on a shaft 30. On the latter is also mounted loosely a gear wheel 29, in mesh with the pinion 37. The gear wheels 28, 29 will therefore rotate in opposite directions while the shaft 27 is rotating. Said gear wheels carry clutch members 31, 32 respectively, which may be constructed as springs adapted to be engaged by the central clutch member D, held to rotate with the shaft 30, but movable lengthwise thereof. It will be understood that in the central or natural position illustrated; the member D is out of engagement with -both springs 31, 32, and the shaft 30 does not rotate; by shifting 'said member to engage either the spring 31 or the spring 32, the shaft 30 will becoupled either with the gear 28 or with the gear 29, and accordingly caused to` rotate in one direction or the other. The longitudinall shifting of member D may be accomplished by means ofa lever 33 controlled either manually or otherwise, for instance by means of a hydraulic or pneumatic cylinder 34 to which the medium under pressure maybe admitted on one side of the piston or the other, as desired. The shaft 30 carries rigidlya pinion 38, in mesh with a gear wheel 39, whichimparts rotation to a suitable train of gears operating the rolls one gearof this train is indicated at 40, but

1 details have not been illustrated, since mechanisms suitable for this purpose are wellknown in the art.

For driving the drums, the following mechanism is provided in Fig. 2: On the shaft 27 is secured rigidly a bevel pinion 41, in mesh with a like pinion 42 on a shaft 43 which carries a worm 44. The latter meshes with a worm gear on a shaft carrying one member 45 of a friction clutch. The other member 46 of this clutch is held to rotate with a shaft 47 aligning with the shaft of the clutch member 45; by means of a shifting lever 48, fulcrumed at 48', the clutch member 46 may be moved lengthwise of the shaft 47, into or out of engagement with the clutch member 45. On the shaft 47 of the drum 5 is secured rigidly a brake disk 49 adapted to be engaged by brake shoes 50, 51. By depressing one of the pedals 52 or 54, motion is imparted to a rod 53, to rock a shaft 55 in one direction or the opposite direction. By means of a crank 56 this shaft is connected with the actuating mechanism of the brake shoes 50, 51, and by means of another crank 57 and toggle links 58, 59 the shaft is connected with the clutch shifting lever 48. These parts are arranged in such a manner that rocking the shaft 55 in one direction will apply the brake shoes and release the clutch, while rocking the shaft in the opposite direction will release the brake and throw in the clutch. A driving mechanism of the same character is associated with the drum 6, Fig. 2 showing a worm 60 on the shaft 43, said wormdriving the clutch member 61, the mating clutch member, 62, being mounted on the drum shaft 63 and being adapted to be thrown in or out by the lever 64. The brake disk 65 cro-operates with brake'shoes 66, 67.

Pedals 68, 70 serve to rock the shaft 69 in opposite directions. This shaft has a crank 71 controlling the brake shoes 66, 67, and another crank 72 which controls the shifting lever 64, through the medium of the toggle links 73, 74. The two mechanisms are alike, except that they are constructed to rotate the friction clutch members 45, 61 in opposite directions; for this purpose, the two worms 44, 60 are of opposite pitch, Athat is to say, one of them is left-hand, and the other righthand.

The connection of the blank 11 with the drums 5, 6 by means of flexible intermediate members, such as the cables 7, 8, presents numerous important advantages. When the ends of thev blankare fastened directly to the drums, according to the former practice, the

length of the blank must evidently be at least the roll 2 clockwis Athe drum 5, will be vantages will appear presentlyk as the operation is further described.

At the beginning, one end of the blank is fastened to one of the gripper-s, for instance the gripper 10, then the other end ofthe blank is inserted or threaded between the rolls l, 2 and fastened to the other gripper 9, which for this purpose has been brought as near as possible to the rolls. By means of the mechanism B or its equivalent, the gap between the rolls l, 2 is adjusted to the width desired for the first operation or pass during which, in the case assumed, the blank moves from left to right. For this purpose, the shift lever 33 is moved to couple the shaft 30 with that one of the gears 28, 29 which will cause the roll 'l to rotaie contraclockwisc and Furthermore, the pedals controlling the rock shafts 55' and 69 are operated in such a manner that the shaft t7 will be released from the action of the brake shoes 50, 51 and at the same time coupled with the continuously rotating clutch member 45, while the shaft 69 will be disconnected from the clutch member 61 and placed under the restraining action or resistance produced by the engagement of the brake shoes 66, 67 with the disk 65. rEhe drum 5 will therefore be driven to rotate clockwise, while the drum 6 will be rotatedin the same direction, by the pull of the blank 11 fed by the rolls A1, 2 and the drum 5. The action of the brake shoes66, 67 will produce the proper longitudinal tension in that'portion of the blank which is on its way to the rolls, while the blank portion which has passed between the rolls and then travels on placed under tension by the pull of the drum 5. For this purpose', the clutch member 4:5 is rotated at a higher speed than that which would be required to give the blank 11 the same linear speed that it obtains from the action of the rolls, and the clutch member 45 is allowed a certain amount of circumferential slip relatively to the clutch member 46, the friction between said clutch members producing the desired tension in the leading portion of the blank, that is, the portion which has passed between the rolls.

It will be obvious that the rolling operation can be continued until the rear end or following end of the blank 11 is almost in contact with the rolls. In other Words, practicallv the entire length of the blank can be rolled, only the short portions held by the grippers 9, 10 constituting waste. This slight waste is of negligible importance, particularly since,

` as a rule, the blanks p'assedthrough my improved rolling have received a preliminary hot rolling treatment which reduces their ends to a condition requiring them to be discarded as waste.

It will be understood that during the first pass the blank will remain straight or plane,

since I have assumed a case in which therolls 1, 2 is reduced 'by the mechanism B,

either before the blank begins to movefrom right to left, or preferably immediately after it has' started such movement, it being easier to reduce or narrow the gap while the rolls and the blank are in motion than when they are stationary. When the gripper 9 has come close to the rolls, the machine is stopped, and thereupon the blank is subjected to a third pass from left to right), and this alternation of passes in opposite directions, with a readjustment of the gap after each pass, is ref peated until the blank has been reduced to the desired thickness.

Each individual operation or pass not only reduces the thickness of the blank, but increases its length. Thus after the first pass or one of the later passes, the length of the short blank referred to a-bovefwill have become greater than the distance between the drums 5, 6, ad from that time on, during the subsequent passes, a portion of the blank will wind on the drums, as shown in Fig. l with respect to the'drum 6. By this time the thickness of the blank has been reduced sufficiently to enable it to bend around the drumcreadily.

-During the preceding pass or passes, however,

the take-up drum, but when it is desired to.

coil the finished blank for further treatment or storage and shipment, a separate coiling device is employed for this purpose. Such a device is indicated in Figs. l and 2, where 18 is a coil-forming roller located to the left of the drum 6 and driven in any suitable manner,ffor instance by a belt or chain 18. The ends of 'the roller are one of which, 19, may be swung aside about a. vertical pivot 20, so as to clear a path ufor removing the finished coil lengthwise of theroller. It will be understood that' immediately before thelast pass, or after such pass,

. one end of the blank would be disconnected from the gripper 9 or 10, as the case might journaled in bearings vbe,

and secured to the coil-forming roller 18, which would then be rotated to coil the blank, the other end of which would be detached from the second gripper atnthe proper time.

The coil-forming roller is of a diameter of, say, about 50 centimeters. This is the size that has been customary 1n former practice may be given a for the drums when the latter were employed .as coil-forming rollers. When the blank is coiled on a separate roller, according to my invention, and not on the drums,\tllese drums much larger dia-meter, say 1 meter or over. Increasing the diameter` of the drums 5, 6 (in other words, making themj` considerably larger than the coil-forming roller 18) has very distinct advantages. First, the amount of bending (radius of curvature) given to the blank when itW engages the drums 5, 6, is much more favorable to an efficient operation. Not only is the power required for drivingthe pulling drum reduced as the diameter of the drum increases, (since less power is consumed for the mere bending of the blank), but there is a material reduction of the internal strain which during the bending of the blank arises from the fact that the outer surface of the bent blank is stretched lengthwise ofthe blank to a greater extent than the inner surface. lObviously, the'l difference becomes smaller as the drum diameter increases. It should be noted that the power consumed for the mere bendin of the blank, decreases at a greater rate t an the diameter of the um; for instance, the

` power required to bend the blank on a drum of 1 meter diameter is considerably less than one-half the power required to bend the blank on a drum of a diameter of centimeters.

' Second, on account of the greater radius of curvature, .I am enabled to bend considerably thicker blanks on the drum than those which could be worked hitherto.

It will be noted that after the two ends of the blank 11 hav'e been secured to the grippers 9, 10, there is n o need of disconnecting the blank from the grippers during the sub- A sequent operations or rolling passes,and this greatlysimpliiies the manipulation of the apparatus, and reduces the time re uired for the entire rolling operation, sinceV avoid the loss of timeinvolved in' the repeated attaching and detaching of the blank which were necessary in the practice prevailing hitherto. As Il havestate above, the` short end portions ofthe blank, which are held by the grip'pers 9, 10, do not pass between the rolls -1, 2 and are therefore to be considered as4 v waste.

of the blank.

I have found that a great improvement can l be effected by subjecting the blank to a much greater longitudinal tension than has been customary hitherto. The former practice was to place the blank under a tension just sufficient to prevent looseness in the coiling I have ascertained that far superior results are obtained when the longitudinal tension of the blank is increased considerably, even to a point in the neighborhood ofthe elastic limit' (just below such limit). Tests have demonstrated the fact that with increased longitudinal tension of the blank there is a very material reduction "of the power required for operating therolls between whichthe blank passesduringthe rolling operation. This increased longitudinal tension is applied, as a rule, to both the leading and the following portion of the blank, in other words, both in advance and in the rear of the rolls. According to the indications obtained by l,these tests, it. would seem that the increased longitudinal tension performs part of the rolling work (reduction in the thickness of the blank and-increase in length) which in prior practice is performed exclusively by the rolls. This tension is produced, of course, by the pull of one drum on the leading portion of the blank and by the resistance which the braking device opposes to the motion of the following portion of the blank.

As the thickness of the blank decreases after thesuccessive passes of the rolling'operation, the pull and the 'resistance which place the blank under longitudinal tension are preferably reduced progressively, that is toy say, after each pass, in order to obtain a practically uniform longitudinal tension, and particu arly in order to avoid stressing the material beyond the elastic limit.. The

resistance opposed by the brakii device may be varied by means of any suita le arrange- -ment, for instance by a handwheel E the turning of which moves the brake shoes 50, 51 or 66, 67 toward or from each other. The pull exerted by the drum 5 or 6 may be varied by adjusting the fulcrums 48 and 64' of the levers 48 and 64 respectively lengthwise of the axes of the shafts 47 and 63 respectively.

For this purpose, I may employ the mechanism shown in Fig. 9, where the fulcrum 48 is provided on a slide 94 movable parallel to the axis of shaft 47, by means of a shaft 95 mounted to turn in bearings 96 but held against longitudinal motion. The shaft 95 has a screw orti'on fitted into a c rrespondingly threa ed hole in the slide 4, and a. handwheel 97 is rovided to rotate this shaft. It will be un erstood that an adjusting mechanism of the same character wouldbe provided for the fulcrum 64. Crum-adjusting mechanisms have omitted from Figs. 2. and 7, in order not to confuse these views.

These fulbeen Ilength too great to allow them to be fastened at once to the gripers 9, 10. Such a blank would first be rolledin the flat condition,

without using the drums 5, 6 and the exibl'e connectors 7, 8, and when the thickness of the blank has been reduced sufficiently (say, to

1/6 or 1/8 of aninch) to enable the blank to be bent around the drums 5, 6, its ends would be fastened to the gripers 9, 10, and the operation would then proceed as described above. Generally, the operation would start with one or more passes in which the blank would not be connected with the drums 5, 6; but in the rather exceptional case of short blanks', I might connect them at once with the drums, through the'medium of the flexible connectors 7 ,-8, as first described above.

I'have also found that in some cases it is 'desirable to make the longitudinal tension which results from the pull of one of the drums on the leading portionpf the blank, greater than the longitudinal tension which results from resistance opposed by the braking 'device of the other drum, to the movement of the following portion of lthe blank. In fact, the longitudinal tension of such following portion may, in this case, be just sufficient to keep the following portion taut. The above-described adjusting devices for i the brakes and for the fulcrums of the clutch levers 48, 64fenable the attendant to establish these particular conditions whenever he desires.. In all cases where the longitudinal tension ofthe blank is greater on the leading portion than on the following1 portion,v the difference between the two forces will cause the blank to exert a driving action on the rolls 1, 2,'and considerably less power will be required to drive these rolls `through the shaft 30. In fact, the pull of--the one drum on the leading portionoflthe blank may be made to exceed the resistance opposed by the other drum to the movement of the following portion of the blank to such an extent that the rolls may be driven exclusively by the action of the traveling blank. j

n arrangement of this character is shown in Fig. 7, where the only difference over the ar rangement shown in Fig. 2 resides he fact that no gear drive is provided for tge rolls (one of which is shownat 3)., and that-the driving gear for the cliit'ch members 45, 61 is constructed as follows: Said clutch members are secured rigidly to shafts 81, 82 yrespectively, rotated continuously in opposite directions through the medium of spur gears 79, 80 respectively likewise secured rigidly to the respective shafts,'and of intermedia "flpinions 7 8 and 83 mesh with-each other, e pinion the pinion 7 8. The other parts arethe same.

as in Fig. 2, and bear the same reference characters.

One of the advantages ofmy invention is that the distance between the drums 5, 6 may be made relatively small, and this reduces considerably the danger of lateral distortion of the blan Such danger may be further counteracted by arranging a suitable press at each side of the rolls, in the immediate vicinity thereof, that is to say; one press between the. rolls and the drum 5, and the other press between the rolls and the drum 6, to engage, at a point close to the rolls, that portion of the blank'll which at the time is the following portion. Each of these presses is preferably of such a construction that different adjustments may be made at the portions near opposite longitudinal edges of the blank.

An example of a suitable construction of such presses is shown .in Fig. 8, the blank travelin at right angles to the'plane of this ligure. he upper and the lower press member 85 and 84 respectively engage the blank adjacent to one of its longitudinal edges,

-whi'le thepress members 86 and 87 engage "the blank is generally inactive, in other words, its. portions 85, 87 are lifted sufficiently to oppose no) resistance to the passage of the blank. The other press, adjacent to the temporarily following portion of the blank,

is adjusted to exert the proper pressure on the blank whenever required, to exert a braking action additional to that of the brake shoes-50,' 51 or 66, 67 and thus provide an additional safeguard against any lateral wandering or deflection of the blank. It is true the great longitudinal tension to which I subject the blank is by itself a powerful safeguard against such lateral deflection of the blank; yet in some cases, and articularly when the following portlon o the blank is under considerably less tension than its leading side the assistance of 'the press on the following side of the blank may be desirable or necessary.

As a rule, the right-hand and the` lefthand portions of the press will be adjusted to exert equal pressures in some cases, however (as when the attendant .notices atendblank than on the other. I therefore prefer to provide means for the simultaneous vertical adjustment of the upper press members 85, 87 as well as for their independent individual adjustment. A suitable construction of this t pe consists of upright screws 88, 89 secure to the press members or portions 85, 87 by pins 88', 89 or otherwise, so that the screws can not rotate. The upper portions of the screws are in threaded engagement with the hubs of bevel pinions 88, 89")which are held against vertical motion and in mesh with bevel pinions 90 and 92 respectively held to turn with their shafts 90 and 92 respectivelf. The shaft 92 istubular and carries a han heel 93 rigidly. On the shaft 90 is mounted a handwheel 91 held to turn therewith yet slidable lengthwise thereof to bring the handwheel 91 into locking or clutched engagement with the handwheel 93, as illustrated. In this condition, rotation of the handwheel 91 will rotate both shafts 90, 92 alike and therefore effect equal vertical adjustments of the press member-s 85, 87. By sliding the handwheel 91 outwardly until it is clear of the handwheel 93, the connection between the shafts 90, 92 is interrupted, and each of them may be rotated independently by rotating the respective handwheel 91 or 93, thus effecting an individual adjustment of the press member 85 or 87.

Whenever a supplemental resistance is aplied by the press to the movement of the ollowing portion of the blank, care must be taken to adjust properly the resistance which the brake device oifers to the movement of said portion. It will be evident that the propellin action which the blank exerts on the rolls epends on the diiference between the pulling .action of one of the drums on the leading portion of the blank and the total resistance opposed to the movement of the following portion of the blank. Now, this total resistance is the sum of the resistances opposed by the press and by the braking'device res ectively; therefore, if originally only the bra ing device was employed, and then the press is brought into action, or if while both are in action the press is adjusted to a different condition, the braking device will have/to be adjusted to compensate for the additional or the reduced resistance exerted by the press, in order that the total resistance may remain the same. f

The novel mode of operation described above produces a rolled product of very high quality, particularly as regards homo geneity of structure.

The connecting members 7, 8 might (as mentioned hereinbefore) be made of a width substantially equal to that of the blank, say by using steel bands for said members. The

use ofrelatively Wide connecting members would present an additional safeguard- In some cases it will be found that during the initial pass or passes, an apparatus such as shown in Fig. 2 can be operated without using the roll drive connected with the shaft 30, but taking care to make the pull on the leading portion of the blank greater than the resistance at the following portion; in other words, the clutch member D could be left in the neutral position illustrated, and the aph paratus would operate Rin substantially the same manner as the one shown in Fig. 7. During subsequent passes, however, it might be found that the action of the drums 5, 6 alone is insufficient to. continue the operation, and the roll drive connected with the shaft 30 would have to be thrown in to supplement th ction -of the drums. The relative share which this gear drive and the action of the drums have in effecting the rotation of the rolls could be varied from the one limit, referred tol above, at which the gear drive is entirely inactive, to the other limitat which the pull of one drum on the leading portion ofthe blank is exactly equal to the resistance on blank,so that the rolls would be rotated by the gear drive alone.

I have described above the provision of presses, such as the one shown in Fig. 8, for the purpose of preventing, or helping to prevent, anylateral deviation of the vmoving blank. Other means' lmaybe used for the same purpose, expedient of not making the rolls truly cylindrical, but giving them such a proiile that the edge portionsof the blank will be rolled slightly thinner thanl its 'central portion. When employing presses, these may alsobe rovided with lateral guides for the blank. I may add that whenever one of .the press members 85 or 87 is adjusted downward individuall connected from each other) to increase the pressure on that edge portion of the blank, the other member 87 or 85 respectively should be raised individually to reduce thepresjsure on the. other edge portion of the blank by the same amountso that there will be no ChaZnge'in the aggregate pressure of the twoA members, since any such change would require a re-adjustment of the brake shoes 50,

the following portion, of thefor instance'the well-known V (with the handwheels 91, 93.dis

be kept constant. 'As al rule, the brake shoes 50, 5l and 66, 67 are adjusted toexert a less powerful action when the pulling action of one drumon the'leading portion of the blank exceeds the resistance at the following por tion of the blank, than vwhen the rolls are driven exclusively or at least predominantly by the drive gear, such as the one connected with the shaft 30. v

As-the slip clutches 45, 46and 61, 62 have to transmitconsiderable power, their friction surfaces should be exceptionally. largel and in some cases it 'is desirabley to'provideefor cooling them, as by airor water; v

Instead of the particular power drives-.illustra-ted, vI might employ others, for instance, an electric drive for the drums 5 and 6, and in this case the brakingaction might alsobe eifected electrically, for instance by making the driving motor functionasa braking generator as well,- or by an interposed eddy current brake. A specially desirable arrangement would consist of two parts, one

, ofthemrotating continuously and the other,

l given a high number of revolutions as come which is held to rotatewith the drum, being coupled electromagnetically with said con-y tinuously rotating part, but with an adjustable slip action, during'` the time that such drum exerts-a pulling or take-up action; during the' period that the drum supplies the blank to the rolls, the drum would also slip relatively to said continuously rotatin' part, but in a'diii'erent manner. This will Ine understood upon considering the conditions-obtaining if said continuously rotating part is pared with the relatively low number'of revolutions of t e slowl rotating drum. In this case the re ersal o the drum from rotation in one direction (pulling, or"windingonl of the connector 7 or 8) to rotation in the opposite `direction (paying out, or winding-oil of said connector) will involve only a relatively small variation of the slip action, such as will offer no diculty when an electric drive of the character just referred to isemployed. Such. an arrangement would also have the further advantage that the pulling energy could be maintained uninterruptedly'during the reversal of the drum -fromrotation in one direction to rotation in the opposite direction, through anintermediate condition lwhere-.the drum, for just a moment, would have -.no rotationat all. This would be of particular importance when my improved method is'car ied out with veryv high pullingA igh longitudinal tension in forces or verythe blank. Y

The sameeii'ect might beobtained'with an continuously rotating part'of the machine or apparatus, so that such field would exert a metal As a rule, however, would be`v employed in` connection with myY being bent between and the brakinrr l which rotates continuously A.tion and during the bra electric drive in whichj' an electromagneticv v field would rotate' continuously, instead of am v ,7 it,

latter is stationary relatively tothe-adjacent parts.

provision for insuring Aa perfectly leven en- In some cases it is desirableto make special trance of the blank between the rolls. fFor;

this purpose I may employ in llieu of the presses described above, orfinfad'ditionthereto, tension rolls of a type' well-known-'in connection with machines forfstrai vsuc hten-ing sheet tensionrolls f .improved rolling mill onlyafter the blank hasbeen rolled thickness, so that it can not -be injured by said tension rolls.

' vVarious modifications out departing from the tion as set forth' inthe I claim: l

l. A rolling' mill having rolls, drums located at each side of said rolls and adapted for connection with the blank, a slip clutch for the actuation of cach of said drums, a braking device for each drum, anda unitary' controlling mechanism foreach slip clutch L device of the same drum, to release the 'bralking device when thel clutch is thrown in, and to apply the braking device when the rclutch. is thrown out.

2. A rolling mill according to claim 1,v in which there is an electric drive for each drum', and in which the braking device is operated by an`electric current and is either a separate current brakel or the motor connected to function as a generator.

3. A rolling mill according to claim 1, in which there is an electric -drive for each drum, opera-ted by'an electric current and is a sep arate current brake one member of which nature of my invenappended claims.v

down to a relativelysmall' may be made withand in' which the braking device is l rotates continuously at a relatively high l 4. A rolling mill according to claim 1, `in there is-,an electric drive for each' drum, operated. by an electriccurrent and is a separate current brake one member of which at a relatively high speed, said brake also serving as a slip clutch for drivin the drum.

5. A rol ing mill according to claim 1,l in which there is an electric vdrive for each drum, and, in which the brakingdevice is operated by an electric current and com-l prises an electromagnetic field| rotating con.-

tinuously at a relatively high speed, that part of the electric mechanism which is connected with the drum, to said eld both -durin ing condition.

6. Arolling mill, comprising rolls, a drum4 at theside of said rolls for drawing material therethrough, a constantly driven'motor, a driving connection between said motor and slipping with respect the driving condi-v and in which the braking device is said drums including a continuously rotatingshaft, driving connections from said shaft to said drums to cause said drums to rotate in opposite directions, 'slip clutches in said driving connections, and means to engage one of said clutches while permitting the other clutch a slip, whereby to draw said blank through said rolls.

9. In a rolling mill, a pair yof rolls, drums at each side of said rolls upon which a blank may be wound to be drawn back and forth ythrough said rolls, and driving means for said drums including a continuouslydriven shaft, driving connections from said shaft to said 'drums to cause said drums to rotate f in opposite directions, slip clutches in said driving connections, means to engage one of said clutches while permitting the other clutch al slip, whereby to draw said blank through said rolls, means for braking said drums, and means for controlling said clutches and braking means sothat one of saidclutches may be engaged when the other drum is braked. l

10. In a rolling mill as claimed in claim 8, means for exerting different vertical pressures on opposite longitudinal edges of the material.

11. A rolling mill comprising rolls, drums for drawing material therethrough, a motor adapted to rotate in `one direction, a driving connection between said motor and said rolls for driving said motor and including clutching means for driving said rolls in either' direction, and adriving connection operatively connected to said first driving connection between said motor and said clutching means fordrivingsaid drums in opposite directions.

12. A rolling mill as in claim 11, and clutches in said second driving connection between said first driving connection and l each of said drums.

13. A rolling mill as in claim 11, clutches in said second driving connection between said firstdrivng connection and each of said fdrnms, and means for braking each of said drums. I

14. A rollingmill as in claim 11, clutches in said second driving connection between said first driving connection and each of said p drums, and means for braking each of said drums together with control means for causinsana ing braking of each drum when the clutch thereof is disenga ed.

15. A rolling mill for thick blanks having rolls, drums at each side of said rolls of large diameter, means for actuating said drums,

flexible connectors each having one end secured to one of said drums and the other provided with a ri'pper 'adapted to secure one end of the blan ,said connectors being adapted to wind on the respective drums, and a coilforming device additional to said drums said device comprising a winding roll of a diameter considerably less than the diameter of said drums. s

16, A rolling mill for thick blanks having rolls, drums at each side of said rolls of large diameter, means for actuating said drums, iexible connectors each having one end secured to one of said drums andthe other provided with a ripper adapted to secure one end of the blan said connectors being adapted to wind on the respective drums, and a coilforming device additional to said drums, said device comprising a winding roll of a diamy eter-considerably less than the diameter Iof said drum-s, and means connected to said drum actuating means for driving said winding roll.

17. In a rolling mill, a pair of rolls, drums for drawing material through said rolls. a pair of shafts, means for rotating said shafts continuously in opposite directions, a slip coupling between each of said shafts and one of said drums, means to engage one of said couplings and means to disengage the other of said couplings to draw a blank through said rolls.

18. In a rolling mill, a pair of rolls, drums for drawing material through said rolls, a pair of shafts, means for rotating said shafts continuously in opposite directions, a slip coupling between each of said shafts and one of said drums, means to engage one of said couplings andmeans to disengage the other of said couplings to draw a lank through said rolls, means for braking said drums, and means controlled by said coupling disengaging means to actuate said braking means.

19. The method of rolling which consists in passing a blank under tension between rolls while exerting different vertical pressures on opposite longitudinal edges of the blank before it reaches the rolls, to counteract any tendency of the tension to cause lateral deviation of the blank in the rolls.

20. In a rolling mill, a pair of rolls, means for drawing a blank under tension through said rolls, and means for exerting different vertical pressures on opposite longitudinal edges of the blank before it reaches the rolls, to counteract any tendency of the tension to canse lateral deviation of the blank in the rol s.

21. In a rolling mill, a\pair of rolls, drums m hand.

y ERNST BARTEN.

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