US2124880A - Reversible rolling under controlled tension - Google Patents

Description

July 26, 1938. E. B. HUDSON REVERSIBLE ROLLING UNDER CONTROLLED TENSION Original Filed-Oct. 23, 1934 5 Sheets-Sheet l INVENTOR. Emu/N13 Hausa/v.

ATTORNEYS,

July 26, 1938'. E. B. HUDSON REVERSIBLE ROLLING UNDER CONTROLLED TENSION 5 Sheets-Sheet 2 Original Filed Oct. 23, 1934 INVENTOR.

flaw/MB. Hausa/v.

ATTORNEYS.

July 26, 1938. E. B. HUDSQN 2,124,8G

REVERSIBLE ROLLING UNDER CONTROLLED TENSION Original Filed Oct. 23, 1954 5 Sheets-Sheet 3 ATTORNEYS.

July 26, 1938. E. B. HUDSON REVERSIBLE ROLLING UNDER CONTROLLED TENSION .5 Sheets-Sheet 4 Original Filed Oct. 25, 1934 INVENTOR. [aw/1v 5. Hausa/v ATTORNEY$ July 26, 1938. E. B'. HUDSON 2,124,880

REVERSIBLE ROLLING UNDER CONTROLLED TENSION Original Filed Oct. 23, 1934 5 Sheets-Sheet 5 INVENTOR. EDMNB. Hausa/v.

ATTORNEYS Patented July 26, 1938 UNITED STATES PATENT OFFICE REVERSIBLE ROLLING UNDER CON- TROLLED TENSION Edwin B. Hudson, Middletown, Ohio, assignor to The American Rolling Mill Company, Middletown, Ohio, a corporation of Ohio 6 Claims.

My. invention is addressed to the rolling of metal under tension, and will find its greatest utility in the rolling of long strips of metal backwardly and forwardly in a reversible mill or mill combination. For the purpose of disclosing my invention in a clear and readily appreciable manner, I shall describe it in a particular embodiment, it being understood that this embodiment is exemplary only, and that my inventionis not limited otherwise than as set forth in the appended claims. -A method of tension rolling whereby end wastage is eliminated, which is described and claimed in a copending application, Ser. No. 724,931, filed May 10, 1934, and entitled Apparatus and process for tensioned cold rolling in reversible mills, may be employed if desired with the apparatus and method of this invention, with such appropriate apparatus additions as will be understood from a reading of the said copending case.

This'is a division of my co-pending application Ser. No'. 749,591, filed October 23, 1934, and entitled Tension apparatus for reversible mills.

It has hitherto been suggested to roll metal of strip length and sheet width backwardly and for- .wardly through a mill, say, of the four-high type with small working rolls capable of making a heavy reduction per pass. On either side of the mill an apparatus in the nature of a tight coiler is placed. The coiler ahead of the mill, when the strip is moving in one direction, is driven to exert the desired forward tension on the piece, while the coiler behind the mill is braked to exert the desired back tension.

Each coiler is arranged to act alternately as a braking or -pulling device as the direction of rolling is changed. 7

It will be clear that a system ofthis kind presents certain problems, some of which will be set forth. In the coiling devices, Whether used as pullers or as brakes, for a given force applied to the shafts of the drums, theforce applied to the strip will vary inversely to the diameter of the coils on the drums, as will be obvious. The most perfect rolling under tension is dependent upon continuously uniform and unvarying tension, since with a given setting of the rolls a difference in gauge will follow a difference in tension. Even if provision were made in some way that the pulling and braking coilers could exert a constant force upon the strip, yet one would be confronted with those continual and sporadic variations in elongation which arise from non-uniformity of gauge, strain or hardness in the piece being rolled, and from other rolling conditions. An attempt to control the speeds of the various dynamic instrumentalities in the system in accordance with tension variations in the strip, does not wholly succeed became, once there has been a variation in the tension a variation in the rolled piece has been produced. Moreover it is not desired to place any great quantity of apparatus between the mill and the coilers because this increases the length of unrollable strip between the mill and the ultimate attachment of the strip to the coiler drums. Since some of the variations may be cumulative, control of the speeds of the several dynamic instrumentalities is desirable; but because no speed control has rapid enough response to take care of the sporadic tension variations, it is necessary to pro vide some means which will keep the tension constant and unvarying in spite of the factors tending to produce tension change, and then to control speeds in accordance with variations of elongation. This implies means to take up at least a short lengthof strip under a constant force. Finally, there is ordinarily desired in tension rolling a positive tension difierential, i. e. a greater tension in the strip on the outgoing side of the mill than on the incoming side. Since the mill is a reversible mill, this condition must likewise be made reversible.

The solution of these problems constitute the major object of my invention, together with the provision of a relatively simple and compact apparatus easily kept in repair. The ancillary objects of my invention will be understood by one skilled in the art upon reading these specifications, wherein I shall describe the aforesaid exemplary embodiment. Reference is now made to the drawings wherein:

Figure 1 is a vertical sectional view of my apparatus with parts removed for the sake of clearness.

Fig. 2 is an elevational view of an adjustable accumulator device.

Fig. 3 is a plan view of the mill, one of the coilers, and the drives therefor.

Fig. 4 is an end elevation thereof.

Fig. 5 is a side elevation of a coiler and its mountings.

Fig. 6 is an end elevation thereof.

Fig. 7 is a plan view of my accumulator.

Fig. 8 is an end elevation thereof.

- Fig. 9 is an elevational view of an exemplary braking apparatus.

Briefly, .in the practice of my invention I provide a reversible mill I (reference is made to Figs. 1 and 2 for a better understanding of this brief description). This mill is preferably of the four-high type. Guide rolls 2 and 3 are shown adjacent the mill. On either side of the mill there is a coiler, the drums of which are indicated at 3 and 4. These drums, instead of being mounted in the ordinary frames, are held in crook-shaped cradles 4a and 5 which are pivoted to the boiler frames 6 and 1 below the drums as at 8 and 9. Thus, as the cradles tilt, the drums are brought closer to or further from the rolls of the mill. Hydraulic or other fluid pressure cylinders l0 and H tend to rock the cradles so as to urge the drums away from the mill rolls under constant forces. In this way I have provided for a structure in which sporadic variations in elongation may occur without affecting tension, since these variations are taken up by movements of the cradlesgand drums. tent of movement of the drums is, of course, limited; so that it is advisable to control the speeds of the various instrumentalities in accordance with variations in elongation. Each drum will be understood to have a drive, such as an electric motor. Rheostats for these motors respectively are shown at 12 and I3, each equipped with sheaves l4 and 15. Cables l6 and I1, connected with arms on the respective cradles, pass over these sheaves and are counterweighted as at I8 and I9. Thus variations in the positions of the cradles will produce corresponding variations in the drum drives, although a lost motion connection may be made therebetween so that there will be a central zone of no control. It will be understood that the drums may likewise be equipped with braking means for main lieu of a drive when any particular drum is paying out strip.

The mill may be of any suitable type, equipped or not with means for compensating for the offsetting of the working rolls as the direction of rolling changes. I have shown at 20 a loading device for the entrance cradle, and at 2| a receiving device for the exit cradle. The exit cradle is tiltable so that the drum 4 will run'out onto the receiving device. Overhead handling equipment is indicated at 22 and 23.

It has been pointed out hereinabove-that in most instances a positive differential in tension is desired in the direction of rolling. If this were not so, the cylinders I0 and II might continuously have equal fluid pressures imposed upon them, and might conveniently be loaded from the same accumulator. But if rolling is proceeding with movement of the strip 24 to the right in Fig. 1, there will preferably be greater fluid pressure in the cylinder ll than in the cylinder l0; and when the mill is reversed the reverse of these conditions is desired. This may be accomplished by providing a separate accumulator for each of the cylinders, and effectively changing the weights on the accumulators as required. I have devised a simple apparatus for this purpose which I have shown in Fig. 2. Here the accumulator comprises a cylinder 25 mounted on trunnions 26 in a frame 21. A piston, is pivoted to a connecting rod indicated at 28, pivoted in turn to a yoke 29. Rods 30 and 3| are connected at one end to this yoke, pass externally of the cylinder and are guided thereon by rolls 32. Weights 33 are connected to these rods. Connection to the cylinder may be made through a trunnion, and I have indicated at 34 a line connecting the cylinder 25 with a cylinder l l on one of the cradles. A branch 35 of the line may lead to a pump for oil, water, or whatever pressure The ex- I fluid is desired. A gauge 36 may be calibrated to read in pressure or in strip tension. It will be understood that the fluid pressure produced and readily understandable means, be made automatically'responsive to a reversal of the mill.

I shall now proceed to a more particular description of an exemplary embodiment of the various mechanisms which I employ. I have shown in Figs. 3 and 4 the mill, one of the coilers, and the drives therefor. A motor 31, for driving the mill, is reversible or is equipped with a reversible drive. It is directly connected, driving, through a suitable coupling 39, a mill pinion stand of known type. Splined shafts 4| connect the pinions of the stand with the rolls Ia of the mill.

A second motor 42 drives a gear box 44. The low speed shaft of this gear box is connected through a universal coupling 46 and a splined shaft 41 directly to the drum 3 of one of the coilers. The high speed shaft of the pinion stand is connected by a coupling 45 to the shaft 48 of a braking device. This shaft bears a drum 49 connected thereto by an over-running clutch located within the drum. The over-running clutch makes it unnecessary otherwise to connect and disconnect the brake. Cables 50 are wound around the drum to react frictionally therewith. The braking arrangement is more clearly shown in Fig. 9, where 49 again indicates the drum, and 50 the cables. The cables are dead-ended to a base as at 50a. The base bears a standard 51a, to which a scale beam 5| is pivoted as at 5lb. The other end of the cables 50, which is in the form of a loop, is passed over a sheave 50b, mounted upon the scale beam 55. A reversible motor 52 is mounted upon the scale beam, and bears a threaded shaft 52a extending therealong. A weight 5lc is threaded on the shaft 52a, and is arranged to move along the scale beam when driven by the motor 52. It will be clear that as the weight 510 (which has provision for being additionally loaded as desired) is moved outwardly along the scale beam, the tension on the cables 50 will be increased. and the braking action, and therefore the back tension on the piece being rolled, will likewise be increased.

The motor 52 may be controlled by hand if desired, but it is more convenient to do this automatically to control the braking action in such a way that the back tension may be maintained uniform. Since at the time of rolling in the one,

cradle, say, cradle 4a in Fig. 1, so that when this cradle has rocked a predetermined distance in a counter-clockwise direction the motor 52 will be started up and driven forwardly so as to move the weight 51c outwardly along the scale beam until the said motion of the cradle has been arrested. Likewise when the cradle moves a predetermined distance in a clockwise direction, a switch actuated thereby is effective to start the motor 52 in a reverse direction so as to bring the weight 5|c inwardly along the scale beam until the motion of the cradle has stopped. With the suggestion of the automatic operation of the motor 52, the switching arrangement will be clear to one skilled in the art.

The over-running clutch referred to, located within the drum 49 or in connection with the shaft 48, renders the brake ineffective when the corresponding coiler drum is being positively driven in a pulling direction by its motor. However, during the threading operations of the apparatus, it may sometimes be necessary to drive the coiler motor in a reverse direction, which indicates the advisability of the provision of some means to relieve the braking action. To this end I provide an ordinary thruster 52b, located under an endof the scale beam 5!. This thruster may be of an ordinary type well known in the art, and special description thereof is not required. Its function is to push the free end of the scale beam upwardly, thereby relieving tension on the cables 50, and it may be, and preferably is, actuated by a hand control, since relief of the braking action will be required only during threading operations.

The cradle 40. is shown as comprising side pieces 4b and'transverse members 53 and 54. The cylinder ill has a plunger assembly Illa, terminating in a yoke I 0b. This yoke is connected by rods Me to the cross piece 53. Below the cylinder assembly a stop means 55 may be provided, which may be resilient or not as desired.

Further details of the coiling devices are shown in Figs. 5 and 6, where it will be seen that the drum 3 has bearing members 56 and 51, which are in the form of sheaves or rollers permitting motion of the drum along the cradle members 4b when it is desired to remove the drum for loading or rewinding purposes. Suitable anti-friction bearing means are located between the sheave members and the shafts of the drum. The splined shaft 41 from the drive is connected to the drum shaft by a slidable connecting member 58. To connect and disconnect the drum from the shaft 47, I provide a power means to operate the slidable connecting member. This comprises a pressure cylinder 59, arms 50 connected to the piston thereof and also to the connecting member 58. The arms are finally connected to the frame of the coiler by a linkage 6| forming a moving fulcrum therefor. Latch means 62 may be provided to prevent accidental dislodgement of the drum from the crook of the coiler.

An exemplary form of my variable accumulator is shown in Figs. '7 and 8. 63 represents the frame of the apparatus. The cylinder is again shown at 25 and the trunnions at 26. Segmental gear wheels 64 on the trunnions mesh with pinions 65 on a shaft 66 iournaled in frame extensions 63a. The shaft bears a gear 6'! which is connected by a change speed gearing arrangement indicated generally at 68 to a motor 69.

The yoke is again indicated at 29 and the external rods at 30 and 3|. In this particular embodiment, ears l0 and II on the cylinder 25 bear wheels I2 which serve as guides for the rods. The weights 33 are attached to the ends of the rods which are connected by a yoke 14. Spring cushioning means I3 are shown in the upper yoke.

In order to give to the roller in a place ready accessible to him a definite indication of forward and back tensions, I have shown indicators b and b on the frame of the mill 1. These indicators are driven from the respective hydraulic accumulators in any way desired. Preferably they are calibrated to show tension in convenient units. Actually they indicate the angularity of the hydraulic accumulators, and may be directly driven from the trunnions 26 of the accumulators through flexible shafts. I find it more convenient, however, to connect a selsyn motor, indicated at C in Figures '7 and 8, with the corresponding one of the indicators b or b in Figure 1, which is equipped with a selsyn motor. The connections therefore become electric rather than mechanical, and the indicators give a definite indication of the position of the accumulators. They may then be calibrated in the desired tension units.

It will be clear that my invention is not restricted to the particular embodiments of apparatus which I have described in some detail.

My invention as claimed'may be practiced with other apparatus; and modifications in my inven- /tion may be made without departing from the spirit thereof.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is: 1. In combination, a mill, coilers on each side .of said mill, said coilers having drums and said drums being movable toward or away from said mill, drivers and braking means for each of said drums and means for urging said drums away from said mill under predetermined forces, and means for varying said forces inversely to each other as the direction of rolling is changed.

2. In combination, a mill, coilers on each side of said mill, said coilers having drums and said drums being movable toward or away from said mill, drivers and braking means for each of said drums and means for urging said dmms away from said mill under predetermined forces, means for varying said forces inversely to each other as the direction of rolling is changed, said urging means comprising fluid cylinders and said variable means comprising adjustable accumulators.

'3. In combination, a mill, coilers on each side of said mill, said coilers having drums and said drums being movable toward or away from said mill, drivers and braking means for eachof said drums and means for urging said drums away from said mill under predetermined forces, means for varying said forces inversely to each other as the direction of rolling is changed, said urging means comprising 'fiuid cylinders and said variable means comprising adjustable accumulators, each of said accumulators comprising a cylinder, a piston, and weight means exerting force on said piston, said cylinder being tiltable to vary said force.

4. In combination, a mill, coi1ers on each side of said mill, said coilers having drums and said drums being movable toward or away from said mill, drivers and braking means for each of said drums and means for urging said drums away from said mill under predetermined forces, means for varying said forces inversely to each other as the direction of rolling is changed, and indexing means on said varying means to facilitate rapid settings thereof to predetermined forces.

5; In combination, a reversible mill for rolling strip metal forwardly and backwardly, means on each side of said mill for exerting unequal tensioning forces on said strip as it enters and as it leaves said mill, means for inversely varying the forces exerted by said last mentioned means as the direction of rolling is changed, whereby desired relationships between the forward and back tensions on the strip may be had in spite of reversals of said mill, means on each side of said mill for making the forward and back tensions independent of sporadic variations in elongation produced by the mill so as to maintain said tensions constant during the operation of said mill in any given direction, said means operativeto take up under constant forces said variations in elongation, and means for inversely varying the forces exerted by said last mentioned means as the direction of rolling is changed.

- mill in any given direction, whereby the tensions on the strip are rendered independent of said sporadic variations, and varying said take up forces inversely when the direction of rolling is changed.

' EDWIN B. HUDSON.

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