US1892934A - Tension control for rolling mills - Google Patents

Description

Jan. 3, 1933. w, Q CORYELL 1,892,934

TENSION CONTROL FOR ROLLING MILLS Filed Jan. 8, 1930 2 Sheets-Sheet l Jan. v3, 1933..l w C. CORYELL 1,892,934

TENSION CONTROL FOR ROLLING MILLS Filed Jan. 8, 1930 v2 Sheets-Sheet 2 Patented `ian. 3, 1933 Unirse Askreries PATENT erstes WILLIAM o.v CORYELL, or YoUNGsfrowN, OHIO, Assronoa To REPUBLIC STEEL cora- PORATION, or YOUNGsTOwN, OHIO, A CORPORATION or NEW Jnssnv 4'rinvsroiv CONTROL son ROLLING MILLS Application led lanuaryr, 1930. Serial No. 419,276.

VThe present invention-relates to tension control for rolling mills wherein tension'ls applied to the work asfit. is being lacted upon by the mill and the invention consists in novel 5 apparatus for controlling suchA tension. The

inventionis in yone sense related to the method of my prior p-atent #1,618,515 filed F ebruary 22,1927, wherein I disclose a way'of obtaining-great elongations inthe metal worked upon'with a minimum of annealings.' The present inventionjis especially useful in' carrying out the method of that patent.

One object of the present invention is lto devise a control ofthe class described which will permit i of accurate and nice regulation. Another object is to produce a control which will be `especially a'jpplicable to-` continuous mills. "i Other `objects-include freadyoperation of 'the 'control, economy of'its manufacture and maintenance, *and4 durabilityv and eiicien'cy in service-y .f i

The preferred form of the invention 1ncludes working rolls, means for :applying a p'ull to A'the strip to create" inE the outgoing portion ofthel strip a tension which is fairly constant,1retarding the ingoingl end vof the stripby'means'fwhich will drive agenerator which carries an electric load, and :then adjusting 'the load on the generator to give an accurate retarding tension in the strip on the ingoing side of the rolls.l In this way I have found it possible to obtain great uniformity in tension and thereby to make'it possible to adjust the retarding tension to a point approaching the ultimate rupturing tension/of the strip. This means that by the novel retarding means I employ -I can get a maximum reta-rding stress. This when cou pled with the forward pull On the strip gives components which may be of high value for the forming of the resnltants which cause the metal to fiow where the tension rolling of my prior patent is employed.'

Having set forth the character and nature of my invention in this general way I would now call attention, for a better understanding of the same, to the following detailed description taken in connection'with the accompanying drawings wherein the preferred embodiment of the invention is fully set forth.

For determination of the scope of the invention attention is directed to the appended claims.

In said'drawings, Fig. lis a plan view of a continuous mill plant constructed and arranged in accordance with the present invention, parts of the mill being shown in section taken on a plane indicated by the line l-l of Fig. 4; Fig. 2 is a rear elevation of the same; Fig. 3 is a vertical section through one of the mill couplings and gearings, the plane of section being indicated by the line 3 3 of Fig. 1"; Fig. i is a side elevation of the plant arrangement of Fig. l; Fig. 5 is an elevation of gearing through which energy is transmitted to the electric generator of the plant, parts being shown in section taken on a plane indicated bythe line--5--5 of Fig. l; Fig. 6 isa diagram ofthe mechanism of Fig. l illustrating the electrical connections; and Fig. 7 is a diagram of a strip mill plant showing additional control rolls and a modified pulling device. Throughout these views like characters refe-r to like parts.

Referring to the drawings in detail, A designates a strip of metal passing through mills B and C and being wound upon a reel D. The latter serves as a pulling device to place tension in the strip. The retarding orpoWer-consuming mechanism is the electric generator Gr with its loaded circuit F. The pulling device D is here shown driven b-y an electric motor M. In the mill plant of Fig. 7 the reel D is replaced by a pulling machine H of somewhat different construction.

Although the work upon which the mill operates is shown as a metal strip A, it will be understood that the work might consist of metal pieces of other shapes and kinds. In

such instances the pulling devices D and H tion with metal strip as the material worked upon and I have designed the illustrated mechanism for handling that material.

rIhe mills B and C are similar in construction and consequently the description of one will apply to both. Thus, in mill B, and 11 designate the housings whose feet 12 and 13 rest upon the shoes of 14 and 15 extending. transversely of the direction of travel of strip A. The housings may be of any desired construction and are provided with the usual Windows 16 in which are located lower boxes 17 and upper boxes 19. Breakers 18 bear upon the upper boxes 19. These. boxes provvide bearings for the lower roll 20 and the upper roll 21. In the present Lmill the rolls 20 and 21 are backing-up rolls of large diameter for reducing rolls 22 and 23 of small diameter. The latter'are offset-'from the vertical plane through the axes of the rolls 20 and 21. This offset roll construction constitutes the subject matter of my application Serial No. 309,531, led'October 1, 192,8. The bearings for the reducing'rolls 22 and 23 arevprovidedA byboxes 24 `and/25 'carried in any suitable way by the housings-'10 and 11. Each housingis provided with an adjusting'screw 26 which forms the screw-down mechanism of the mill. The lower ends of these-screws press upon the breakers 18. Any suitable screwdoWnmechanism-may be used on these mills. Suitable counter balances' for the rolls will also be employed, but thesearewell known and need not be illustrated. Reference may be hadto my prior Patent No. 1,233,647, dated Iuly117, 1917-, for anexample.

I .In `the 'ca-se of mill C the shoes 14u and '15 upon which the feet12and13 restare shorter than the corresponding shoes 14 and 15 Iupon which the feet12 and 13 ofmill B rest; The lattermill is the one which is connected up to the retarding or power-consuming generator G, andconsequently'the same 'shoes are used for supporting the feet 27 and 28 of a gearcasing 29 containing the gear Wheels 3() and 31 and intended-for transmission of power from the rolls of mill B to the generatorv G. Gear Wheel 30 is keyed to a shaft 32 which is journaledat its ends in suitable ybearings in the Walls of the casing 29. Similarly, gear wheel 31 is keyed to a-shaft 33 which has its ends journaled in bearings in the same walls of the casing and, in the instance shown, in the same vertical plane as the shaft 32.- The adjacent neck 34 ofroll 21 of mill B is coupled to the end of shaft 32 by means of a coupling shaft 35 and sliding couplers 36. In the same way the neck 37 of roll 20 of mill B is coupled to the end of shaft 38 and sliding couplers 39. As a means of support, the coupling shaft 38 has a central cylindrical portion 40 which bears upon a block 41 carried by a frame member 42, at the upper end of box 43 resting upon a suitable support.

To extend this supporting force `to the upper coupling shaft 33, I provide the latter shaft with a central cylindrical portion 44 which rests upon a block 45 carried by member 46 resting upon a block 47 which bears upon the upper portion of the cylindrical bearing surface 40 ofthe low-er coupling shaft 38. The gear wheels 30- and'- 31 mesh with each other and consequently there is no slippage between the rolls 2O and 21 of the mill.

The end of" shaft 33 distant from the mill B is provided with a" coupling'head 48 and .this headlits the head of the coupler 49 and the latterat its opposite ends lits aA coupling head 50 upon the adjacent end of shaft 51 which carries gear wheel 52 which meshes with-pinion53.mountedupon shaft'54 inline witlrgeneratorshaft v62.v 'Bhe-shafts 51 and 54v are journaled -at their opposite.t ends; in bearings 55 and 56, respectively, formed lin Webs 57 and 58 :of a supporting casting: 59.- The latter is independent of theshoes 14-'and 15, but obviously may/be, mounted upon' .any suitable supportE suchl as the-floor.' 60. upon which the slioes'.14and'15are located. The end'of. the shaft 54 which is distant frcmfthe mill BV is connected'by couplingf61 to the end of the shaft62 ofthe rotor of the generator G. 'The parts of the generator. are-suitably supported' upon a base 63, the shaft 62- having bearings64 and 65 extending upward fr'ornthe .base- The generator struoturefmay be varied a l`great deal 5in form andthere-seems to be no necessity of describing-any pariicular generator indetail. 4'Ifhe base63 may rest upon'. any 4suitable -elevationwof the floor 60 which is shown stepped, withportions suited i-n elevationto the .mechanisms installed;

Ilhe reel .D is one devic'ewhich .may belemployed' for giving .tension tothe strip A. When employed-it must be, of course, positively driven. In the embodiment showngthis isaccomplished.y by an electric motor M and al gear train including pinion 66 and gear wheel'67. The reel D comprises a drum 68 mounted uponf'a shaft 69 toI which reel 67 is keyed; The drum-68 'is provided with some means' -for attaching the. end of thestrip.' Such means are well known and as the same in itself forms no part ofthe present invention, it seems unnecessary to illustrate any means of attachment. Ordinarily, a slit of some kind is provided into which the end-of the strip -is inserted. Many such reels.A are on the .market andfavaila'ble to those who would practice the present invention. The shaft 69 upon which the drum 68 is lmounted is journaled in suitable bearings 70 and 72. The former is found in the upper portion of a-pedestal 71 mounted upon the floor 60 as Vare the other various supports. The latter is similarly found in and supported byv a pcdestal 73, also located upon the floor 60. The pedestal 73 also provides a bearing 74 for the pinion shaft 75 to-which the pinion 66 is keyed. A bearing 76 is a mate to the bearing 74 but is mounted upon a separate support 77 `also adapted'to rest upon the floor 60. The shaft extends some distance beyond thebearing 74 toward the shaft 78 of the motor M. The shafts :7 5 and 78 are'in alignment and joined by a coupling 79. Mo-

'torshaft 78 finds its support in bearingsSO and-81 mounted respectively upon pedestals 82and 83 rising from a base 84:. The latter, as vwith the other pieces of apparatus, rests upon .the floor 60. The motor M, like the generator G, is lof Well-known construction and need notbe described in detail. i Thegeneral arrangement of the mill-plant thusv far described is diagrammatically illustrated in Fig. 6. There some ofthe -parts are -omitted for clearness, but the general arrangement will] be readily understood. The generator G, which forms the retarding mechanism has its terminals 85 and 86 connected toa loaded circuit F comprising conductors: 87and 88 which lead respectively from' said terminals 85 and 86, the one to the terminals lof. a seriesfof electric lamps 89 and-.the other tothe movable arm 90 of a rheostatR, Theseveral contacts 9110i the rheostat are connectedv at intervals to the turns of a resistance Winding 92. The connections are in series so that asthe arm 90 is moved to the left, as seen in Fig. 6, the resistance in circuit is cut down, and when moved to the right the resistance in circuit is increased. The left-hand contact 91 is connected by conductor 93 to the other terminals of the lamps 89. Thus We have a simple loaded electrical circuit wherein the lamps 89 are a steady load and the rheostat R provides a variable load.

The motor M which drives the pulling device D has its terminals 94 and 95 connected by conductors 96 and 97, respectively, to supply means 98 and 99 leading from a suitable source of supply of electricity. The motor M, like the generator G, may vary considerably in construction. There are many motors and generators at present on the market which Will serve the purpose required by the present invention.

In operation the strip is threaded between the reducing rolls of the mills B and C and has its end secured to the drum 68 of the pulling device D. The motor M is started and a pull is exerted upon the strip A in the direction of the arrows. The tension thus applied causes the reducing rolls 22 and 23 of each of the mills B and C to press against the strip to apply rolling pressure, and thus reduce the thickness of the strip, flatten it, or otherwise treat it according to the position of the backing-up rolls 20 and 21. The posit-ion of the latter is determined by the positions of the screw-down screws 26. In the instance shown, the mill C is not connected to any driving source but the required reduction pressure is obtained through the screw-down and the action of the oiset rolls against the large diameter backing-up rolls in response to the pull of the strip. The same is true of the rolls of mill B, but in the latter case the rolls are connected to the retarding electric generator G, and that generator is driven by the rotation of the backing-up rolls 20 and 2l. K

As the strip A is advancing, the small diameter rolls 22 and 23 are rotated by the frictional contact or the strip with the rolls, and then the small diameter rolls by frictional Contact with the backing-np rolls rotate the latter. The rotation of the backing-up rolls is communicated to the gearing through the rotor of the generator G. The action of the rotor is resisted by the load upon the external circuit including rheostat R- and lamps 89. lVhen contact 90 is in engagement with the left-hand contact 91, as the parts are viewed in F ig. 6, there is a constant load upon the circuit. That load is produced by lamps 89. This constant load will exert some retardation upon the connected gearing and rolls, andv consequently there will be exerted by the mill B a retardation upon the advance movement of the strip A. here the motor M is a constant torque motor, the pull of the pulling device D will not be lessened by this retardation caused by the mill B, but the effect Will be to increase the tension in the strip A over that which is produced by the pulling device D when acting alone.

It is apparent that the retarding effect produced by the steady load of the lamps 89 may have its application to the strip A varied by the screw-down mechanism of the mill B. Such mechanism might be loosened up lto the point Where the strip A would, through slippage, fail to drive the generator G. But it should be understood that the screw-down mechanism should be adjusted so that there Will be no slippage between the strip A and the roils 22 and 28 on the one hand, or between the rolls and 23 and the rolls 2O and 2l on the other hand. Thus with the steady load upon the generator circuit, a tension is produced in the strip A which is the result of tension applied by the pulling device D and an opposing tension app-lied by the mill B. The constant load may be determined Within desired limits by the number of lamps 89 included in circuit. The eii'ect of this is to similarly determine roughly the tension in the strip A. F or refinements in adjustment of the tension in the strip the rheost-at R will be used. By shifting its arm 90 back and forth over its contacts 91 the load on the generator circuit Will be varied, and accordingly the resistance offered to the rotor of the generator will be varied, and this variation Will be communicated to the gearing through the rolls of mill B. Thus, by a deft handling of the rheostat arm 90 it will be possible to obtainsuiiiciently reined tension adjustments. Workmen withthe apparatus will soon. acquire the ability to obtain nice-results with diferent kinds of work.

Instead 'of employing a reel for thepulling device, I may prefer in some installations to .employ a pulling machine such as the machine H diagrammatically illustrated in Fig. 7. The use of such a pulling machine Will allow the strip or other workto passcontinuously through 'the plant from one end -to the other. In other Words, the pulling machine provides for a continuous straightaway operation ofthe material being `acted upon. In this diagram the-*strip firsty passes 'between rol-ls L which may` be pinch rolls or the rolls of a small mill. These engage the Work and pass it along toward the mill B. After passing through thel mills B and C the strip A travels around the drums 100, 101, A10:2, and 103 of the pullingmachine H. After leaving the drum 103 thefstrip passes between rolls N which arethe last to actA upon the strip. The pullingr machine .H has-its drums-individually driven, and -these drums act likeuc'apstans to pull upon' the strip by friction'al engagement with it. To insure proper fric-tion', the rolls TN must be positively driven to exert a slight pull upon the strip leaving the last Jdrum'103 of vthe pulling machine. It is believed that this pulling machine need not be further described, as a full description and illustration of the same will be found in myprior application, Serial No. 280,681, {iled May 26, 1928.

In carrying out my invention it will be apparent that certain alterations may: be madein the mechanisms andjarrangements illustrated without departing from the spirit and scope of the invention. Thus, thelamps 89 in the circuit F might bevreplaced by other energy consuming devices. Again,'as indicated, different pulling devices might be employed to take the place of the reel D and pulling mechanism H. Likewise, different types of mills might be employed. Other changes will also suggest themselves to per# sons skilled in the art.A I, therefore,ldo not Wish to be limited to the specific mechanisms and arrangements shown, but aim to cover by t-he terms of the claims all such alterations and modifications as rightly come within the spirit and scopeof my invention.

IVhat I claim as new and desire to secure by a patent of the United States is:

1. In a cold rolling strip mill, working rolls for engaging and operating upon the strip as it passes between them, means coperating with said rolls to produce a high substantially constant tension in the outgoing portion of the strip, means for restraining the ingoing portion of the strip, a loaded elec-v tric generator driven by said restraining means and operative through the latter to exert an even retarding tension in the ingoing applying aihigh .substantially constant -pulfl upon the strip. onthe voutgoing side of' said main rolls, auxiliary rolls for-engagingand retarding the strip on the ingoingsideof 'saidmain rolls, a loaded'electrio generator driven by' energy derived from said auxiliary rol-ls and-operative through the latter yto exert an'even retarded tension-'inthe strip yon the .ing'oing side ofsaid mainrolls, 'andi-'rmeans for regulating the load on said generator# to nicely" adjust theretarding tension on'the ingoing side vof said main rolls, whereby` the retarded tension `in the strip may' be'rai'sedto, and maintainedin, proximity to the Iultimate rupturing tension of the strip.-7V In witness whereof, Ihereuntojsub'scribe my name this L1th dayof Jan., A. D. 1930.

f "'WILLIAM C. CO'RYELL.

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