US2167549A - Tension apparatus for reversible mills - Google Patents

Description

July 25, 1939. B HUDSON 2,167,549

TENSION APPARATUS FOR REVERSIBLE MILLS Filed Oct. 23, 1934 5 Sheets-Sheet l INVENTOR. 5pm 5. Hausa/v.

ATTORNEYS.

July E B HUDSON 2,167,549

TENSION APPARATUS FOR REVERSIBLE MILLS Filed Oct. 23, 1954 SSheets-Sheet 2 INVENTOR.

an m 11% 5mm, fi/vuasa/v.

ATTORNEYS July 25, 1939. E. s. HUDSON TENSION APPARATUS FOR REVERSIBLE MILLS Filed Ot. 25, 1954 5- Sheets-Sheet 3 INVENTOR. fflW/A/fi. Hausa/v.

BY ..-x r I ATTORNEYS.

July 25, 1939. B HUDSQN 2,167,549

TENSION APPARATUS FOR REVERSIBLE MILLS Filed Oct. 23, 1934 5 Sheets-Sheet 4 I NVENT OR. [aw/NB. #005 ON.

ATTORNEYS.

July 25, 1939. E B HUDSON 2,167,549

TENSION APPARATUS FQR REVERSIBLE MILLS Filed Oct. 23, 1934 5 Sheets-Sheet 5 film-,8, 70 as; is: n 68 I INVENTOR. fan W5. Hausa/v.

BY y

ATTORNEYS.

Patented July 25, 1939 UNITED STATES 2,167,549 TENSION Arman-res Foa REVERSIBLE mus Edwin B. Hudson, Middletown, Ohio, assignor to The American Rolling Mill Company, Middletown, Ohio, a corporation of Ohio Application October 23, 1934, Serial No. 749,591..

12 Claims.

My invention is addressed to the rolling oi metal under tension, and will find its greatest utility in the rolling of long strips of metal backwardly and forwardly in a reversible millor mill combination. For the purpose of disclosing my invention in a clear and readily appreciable manher, I shall describe it in a particular embodiment, it being understood that this embodiment is exemplary only, and that my invention is 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, Serial Number 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.

In this application I have'claimed the organization of reversible mill, tensioning apparatus and means for maintaining tension constant in spite of elongation variations. In a copending case, Ser. No. 749,592 filed October 23, 1934, now Patent No. 2,124,880, and entitled Reversible rolling under controlled tension, I have claimed the adjustable tensioning feature and the proc-,

ess incident to the use thereof.

It has hitherto been suggested to roll metal of strip length and sheet width bachwardly and forwardly 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 orpulling device as the direction of rolling is changed.

It will be clear, that a system oi this kind presents certain problems, some of which will be set i'crth. In the coiling devices, whether used as pullers or as brakes, for a given force applied to the shafts of the drums, the force 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 difierence in gauge will follow a diiierence in tension. Even if provision were made in some way that the pulling and braking coilers could exert variations in elongation which arise from nonuniformity 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 because, 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 provide 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 length of strip under a constant force. Finally, there is ordinarily desired in tension rolling a positive tension differential, 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 bemade reversible.

The solution of these problems constitute the major objects of my invention together withthe 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. i 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 exemplar 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 coiler 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 I0 and II 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 cradles and drums. The extent 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 i2 and I3, each equipped with sheaves l4 and I5. Cables i6 and I1, connected with arms on the respective cradles, pass over these sheaves and are counterweighted as at i 8 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 use in 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 l0 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 accom plished 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 I 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, 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 II on one of the cradles. A branch 35 of the line may lead to a pump for oil, water, or whatever pressure fluid is desired. A gauge 36 may be calibrated to read in pressure or in strip tension. It will be understood that the fluidpressure produced by this type of accumulator may be readily varied by tilting the cylinder 25 on its trunnions. The pressure will be greatest with the cylinder in a vertical position, and will be scaled down to zero as the cylinder is turned in either direction through an angle of 90 degrees. Accumulators of this type form a facile means of adjusting the forces acting on the take up means, speedily and accurately. The cylinders may be tilted by machinery, and the tilting of them, may, by simple and readily understandable means, he 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 la 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 5"). 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 Me (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 byhand 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 direction that coiler which is braked will not be positively driven by its corresponding driven motor, such a control amounts to a control of a dynamic instrumentality in the assembly, and may be eiiected by similar means. It is convenient to attach a switch to the corresponding cradle, say, cradle 4 in Fig. 1, so that when this of the scale beam upwardly, thereby relieving 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 5lc outwardly along the scale B 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 510 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 9 or in connection with the shaft 45, 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 end of 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 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 4a is shown as comprising side pieces 41) and transverse members 53 and. 54. The cylinder ID has a plunger assembly Illa, terminating in a yoke lob. This yoke is connected by rods 10c 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, wherein it will be seen that the drum 3 has bearing members 55 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 55. To connect and disconnect the drum from the shaft 41, I provide a power means to operate the slidable connecting member. This comprises a pressure cylinder 59, arms 8d 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 52 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. 53 represents the frame of the apparatus. The cylinder is again shown at 25 and the trunnions at 25. Segmental gear wheels 84 on the trunnions mesh with pinions 85 on a shaft 56 Joumaled in frame I extensions 53a. The shaft bears a gear 81 which In this particular em-' The weights 33 are attached to the ends of the 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 generator, indicated at C in Figures 7 and 8, with the corresponding one of the indicators b or b, which is equipped with a; selsyn motor. The connections therefore become electric rather than mechanical, and the indicators givea definite indication of the position of the accumulators. They may then be calibrated in the desired tension units.

The word constant as applied to force or tension in the specification and claims, should be construed as implying that the force or tension m for any given setting of the apparatus during the operation of the mill in a given direction, is a force or tension not characterized by substantial variations, as distinguished from forces or tensions which are characterized by sporadic substantial variations, and as distinguished from forces or tensions which, while substantially varying from time to time, nevertheless have their variations so controlled or compensated for as to have a substantial constant mean or average value.

stricted to the particular embodiments of apparatus which I have described in somedetail. My invention as claimed may be practiced with other apparatus; and modifications in my invention 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, a crook-shaped cradle adapted releasably to hold a winding drum, a winding drum in the crock of said cradle. a pivot for said cradle below said crook, and constant-force means for tilting said cradle on said pivot so as to increase the distance between said mill and said drum.

2. In combination, a mill, a crook-shaped cradle, a winding drum; in the crock of said cradle, a pivot for said cradle below said crook, and constant-force means for tilting said cradle on said pivot so as to increase the distance between said mill and said drum, said constanting means for said drum acting thereon indeperidently of the position of said cradle.

4. In combination, a mill, a cradle, a winding drum in saidcradle, said cradle being tiltable about an axis interspaced from the axis of said drum, constant force means acting to tilt said cradle so as to draw said drum further from said mill in the direction of rolling, driving means for said drum acting thereon independently of the position of said cradle, control means acting on said driving means, and actuated by changes of movement of said cradle.

5. In combination, a mill, a crook-shaped cradle, a winding drum in the crook of said cradle, a pivot for said cradle below said crook, constant-force means for tilting said cradle on said pivot so as to increase the distance between said mill and said drum, and driving means for said drum so connected thereto as to have no efiect on the tilting of said cradle.

6. In combination, a mill, a crook-shaped cradle adapted releasably to hold a winding drum, a winding drum in the crook of said cradle, a pivot for said cradle below said crook, constant- !orce means for tilting said cradle on said pivot so as to increase the distance between said mill and said drum, and driving means for said drum so connected thereto as to have no effect on the tilting of said cradle, a controller for said driving means, said controller being connected to said cradle at a point remote from said pivot.

'7. In combination, amill, a cradle, a drum, movable bearings for said drum mounted in said cradle, a pivot for said cradle, run-out means for said drum, and means for tilting said cradle within a given range to vary the distance between said mill and said drum in the direction of rolling, and beyond said range to deposit said drum on said run-out means.

8. In combination, a mill, coilers having drums on both sides of said mill, said drums being movable toward and away from said mill in the direction of rolling, and constant-force means uriging said drums away from said mill on both si es.

the direction of rolling, constant-force means urging said drums away from said mill on both sides, alternatively operable braking and driving means for said drums on both sides of said mill, and controllers for said driving means, said controllers being actuated by the positions of said drums with respect to said mill.

11. In combination, a mill, an oppositely disposed, crook-shaped cradle on each side thereof, drums mounted in said cradles, said cradles being movable in the direction of rolling to bring said drums toward and away from said mills, and constant force fluid cylinders acting to move said cradles to bring said drums away from said mill.

12. In combination, a mill, an oppositely disposed, crook-shaped cradle on each side there- 01', drums mounted in said cradles, said cradles being movable to bring said drums toward and away from said millin the direction or rolling, constant force fluid cylinders acting to move said cradles to bring said drums away from said mill, drives for said drums, controllers for said drives, and means connecting said controllers with said cradles.

EDWIN B. HUDSON.

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