US2072122A

US2072122A - Rolling mill

Info

Publication number: US2072122A
Application number: US755886A
Authority: US
Inventors: Alonzo B Montgomery
Original assignee: COLD METAL PROCESS CO
Current assignee: COLD METAL PROCESS CO
Priority date: 1934-12-04
Filing date: 1934-12-04
Publication date: 1937-03-02
Anticipated expiration: 1954-03-02
Also published as: DE685904C; BE412396A; FR798109A; GB465745A

Description

March 2, 1937. A. B. MONTGOMERY ROLLING MILL Filed Dec. 4, 1954 6 Sheets-Sheet 1 R O T N E v m March 2, 1937. A. B. MONTGOMERY 2,072,122

ROLLING MILL Filed Dec. 4, 1954 6 Sheets-Sheet 2 A. B. MONTGOMERY March 2, 1937.

ROLLING MILL Filed Dec. 4, 1934 6 Sheets-Sheet 5 Q; INVENTORN March 2, 1937. A. B. MONTGOMERY ROLLING MILL Filed Dec. 4, 1934 6 Sheets-Sheet 4 INVENTOR March 2, 1937. A. B. MONTGOMERY 2,072,122

ROLLING MILL I Filed Dec. 4, 1934 6 Sheets-Sheet 5 INVENTOR ROLLING MILL Filed Dec. 4, 1934 6 Sheets-Sheet 6 6. INVENTOR Patented Mar. 2, 1937 2,072,122 ROLLING MILL Alonzo B. Montgomery, Youngstown, Ohio, as-

signor to The Cold Metal Process Company, Youngstown, Ohio, a corporation of Ohio Application December 4, 1934, Serial No. 755,886

20 Claims My invention relates to the rolling of metal and, particularly, to the hot rolling of strip and a mill therefor.

In the patents to Keeney et al. No. 1,918,968,

and Steckel No. 1,977,214, there are disclosed fourhigh reversing mills with coiling furnaces on opposite sides thereof for hot rolling strip. My invention is concerned generally with improvements in mills of this type.

Commercial use of mills of the Keeney and Steckel type has disclosed the fact that it is sometimes difiicult to cause the material being rolled to enter the rolls properly, namely, at precisely right angles to the plane containing the roll axes. The hot strip, being of comparatively small thickness in the later stages of rolling, has little or no rigidity and it has been found that the strip or the slab from which it is rolled, may become cambered or elongated more along one diagonal than the other if great care is not exercised in directing the piece properly into the mill.

Further difiiculty has been experienced in causing the leading end of the material properly to engage the coilers within the furnaces on opposite sides of the mill. It frequently happens that the leading end of the piece becomes bent at a slight angle to the main body thereof and this condition, if not corrected, makes it diflicult or impossible to cause the material properly to engage the coiler.

I have invented a rolling mill which overcomes the above-mentioned disadvantages of the known mill construction. In accordance with my invention, I provide side guides on both sides of the 5 mill and operate the guides successively to provide a parallel guiding throat on the entering side of the mill and a tapered guiding throat on the' other side of the mill. The conditions of the guides on the two sides of the mills are reversed automatically by a change in the direction of the movement of the piece. Means are provided for adjusting the guides initially to cooperate with materialof any desired width within the range of a particular construction.

My invention also includes means for flattening or leveling the leading end of the piece prior to engagement with the furnace coiler. This means takes the form of a series of flattening rolls adjacent the furnace mouth. In passing through the rolls, the end of the strip is straightened or flattened so that proper engagement with the furnace coiler is insured practically without exception.

I also provide pinch rolls for feeding the material toward the mill and, after passing through the mill, toward the coilers, between passes,

whereby the strip is properly started on the latter. These pinch rolls are automatically raised when the strip has been properly started. They are also withdrawn when the material being rolled is handled back and forth through the mill in the flat without coiling between passes.

For a complete understanding of the invention,

reference should be made to the accompanying drawingsillustrating a present preferred embodiment thereof. It is to be understood, however, that other embodiments of the invention may be constructed within the scope of my broader claims. Referring to the drawings:

Figure 1 is a horizontal section through a mill having my invention incorporated therein showing parts in plan;

Figure 1A is a partial, sectional view similar to Figure 1 showing a slightly modified form of construction;

Figure 2 is a partial side elevation with'the mill housings removed for the sake of clearness;

Figure 3 is a partial sectional view along the line IIIII[ of Figure 2, showing parts in elevation;

Figure 4 is a partial, vertical section through the coiling furnace showing other parts in elevation to a slightly enlarged scale;

Figure 5 is a side elevation similar to Figure 4 showing a modified form of construction embodying pinch rolls particularly adapted for automatic operation, as well as flattening rolls;

Figure 6 is a vertical, sectional view along the line VI-VI of Figure 5 showing parts in elevation;

Figure 7 is a partial, sectional view along the line VII.VII of Figure 5;

Figure 8 is a schematic diagram of the automatic control system for the apparatus of Figures 5 through '7; and

Figure 9 is a similar view of the system for controlling the guides of Figures 1 through 3.

Referring in detail to the drawings, a mill l0 comprises housings H having windows l2 for receiving bearing chucks adjustably positioned therein. Backing rolls l4 and working rolls l5 are journaled in the chucks, the rolls preferably having anti-friction bearings, not shown. The housings H are connected by transoms l6.

Auxiliary housings l8 are positioned on opposite sides of the mill. Roll tables l9 extend between the housings l8 for conveying material to and from the mill rolls. Furnaces 20 having coilers 2| therein are positioned at a convenient distance from the mill. Tilting guides 22 are provided on the roll tables IQ for diverting material advancing through the mill from a horithat in which the strip moves. The remainder I of the strip is then drawn around a scale-breaking roll 24 at the edge of the furnace mouth and wound up on the coiler.

A base 25 is carried between each of the auxiliary housings l8. Bottom guides 26 are pivotally supported on the bases 25 at 21. The guides 26 are also supported by flat seats 28.

Top guides 28 are pivoted at 30 to the transoms i6 and are suspended from angle bars 3| extending across the mill between the chucks |3 for the top backing rolls, by links 32. The inner ends of the

guides

26 and 29 are shaped to conform closely to and are actually in contact with the work rolls to effect a stripping action in case the piece tends to follow around the periphery of one or the other of the rolls.

In the subsequent description of the invention, I shall refer specifically to the equipment on the right-hand side of the mill only, as shown in Figures 1, 2 and 4, but it will be understood that duplicate equipment is employed on the opposite side of the mill.

Screw shafts 33 are slidably mounted in the housing l8 parallel to the axes of the mill rolls. Side guides 34 are supported on the screw shafts 33 by hinged joints 35. The guides 34 have a plane inner surface 36 with recesses into which anti-friction rolls 3'! are let. The mill ends of the guides extend to a point closely adjacent the rolls, as shown in Figures 1 and 2. The outer ends of the guides are pivotally supported on nuts 38 traveling on a screw shaft 39 journaled in the side frames of the table IS. The ends of the screw shaft 39 are oppositely threaded so that on rotation of the shaft, the outer ends of the guides are moved toward or away from the center line of the table I9.

From what has been said, it will be apparent that my invention provides side guides which may be disposed in parallel relation, as shown on the left-hand side of the mill in Figure 1; or in angular relation, as shown on the right-hand side of the mill in Figure 1, for the purposes, respectively, of definitely and positively guiding the leading end of an advancing strip into the rolls at the proper angle thereto, and providing a tapering throat for receiving the end of the piece as it emerges from the mill. I shall now describe the mechanism for operating the guide supports to bring about the proper relation of the guides at the proper time.

The outer ends of the guides may be adjusted toward or away from each other through the shaft 39, as already described. This adjustment is effected by a hand wheel 46 having a pinion 4| meshing with a gear 42 along the screw shaft 39. A suitable pedestal bearing 43 is provided for the hand wheel shaft 44. The outer ends of the guides 34 are adjusted manually to the proper spacing before commencing the rolling.

The adjustment of the inner ends of the guides 34 is effected through the screw shafts 33. Gear gamma cases 46 attached to the housings I. enclose gearwheels 46 having their bores threaded for engagement with the shafts 33, and pinions 41 keyed to shafts 48. Hand wheels 48 permit manual adjustment of the screw shafts 33. These shafts are normally driven from extensions 50 of the shaft of one of the rolls 5| of the table l3. The'rolls of the table are driven from a line shaft 52 through the usual bevel gears by a reversing motor, not shown. Between the shaft extensions 50 and the shafts 48. are positioned friction clutches 53 and law clutches 64 having operating levers 55. The purpose of the friction clutches is to permit the rotation of the shaft 48 to be arrested after a predetermined movement thereof without stopping the operation ofthe roll 5|. The jaw clutches 54 permit the shafts 33 to be freed from the table drive while being manually adjusted.

The friction clutches 53 have detents 56 thereon cooperating with stops 5'! on the housing? l8 to limit rotation of the shaft 48 to the desired extent. After the detents engage the stops, the adjustment of the shafts 33 ceases but the roll 5| continues rotating with accompanying slippage of the clutches 53.

It will now be apparent that once the outer ends of the guides 34 have been adjusted, the inner ends of the guides will be spread to form a tapering throat or moved together to parallel position with the reversal of the drive for the rolls of table IS. The detents and'stops controlling the amount of rotation of the friction clutches will determine the amount of movement imparted to the inner ends of the guides and may, if desired, bemade adjustable. It will be understood, of course, that the guide-operating mechanism is designed so that the guides will be spread at the mill end when the table rolls are driven in such a direction as to' move material away from the mill. At the same time, the guides on the opposite side of the mill will be actuated to parallel position. the material advancing toward the mill is definitely and positively alined at right angles to the plane containing the axes of the mill rolls. The

In this way,

emerging material is in no wise obstructed but be adjusted initially by hand after disengaging ment of the inner ends of the guides is determined by the location of the detents 56 and stops 51. In the construction illustrated, I have assumed that one complete revolution of the shaft 58 will produce the necessary movement of the inner ends of the guides.

Referring now particularly to Figure 4 for a disclosure of the flattening rolls, housings 66 supported on side members of the roll table l3 have bearing chucks 6| movable vertically therein by means of a pneumatic cylinder- 62. Rolls 63 and 64 journaled in the chucks 6| cooperate with adjacent rolls 65 of the table IS. A roll 66 also journaled in the chuck 6| cooperates with a roll 61 journaled in adjustable chucks 68. The chucks 68 are actuated by pneumatic cylinders 63.

The

rolls

63 and 65 may be driven and when the former is lowered into engagement with the latter, they serve as pinch rolls to feed the strip toward the mill from the coiler 2|. When the the clutches 54. Thereafter, the range of move- 55 strip has been started through the mill and engages the coiler on the opposite side thereof, the chucks 6i are preferably raised and the

rolls

83, 64 and 66 lifted oi? the strip. The chucks 88 of the rolls 61 are preferably lifted at the same time as the chucks -6I. In its normal lower position, however, the roll B'Iis effective to assist in flattening or leveling the leading'end of the material in its passage from the mill to the coiler. The pinch rolls 63 are lowered, of course, at this time. If the leading end, after. passingthrough the pinch rolls, is deflected downward, it will engage the roll 61 and then the roll 85. On passing between the rolls 64 and 65, the end will be flattened sufliciently to engage the coiler 2| without difficulty. Similar results occur if the leading end of the piece is deflected upward, in which case it will engage the

rolls

66 and 84 successively, and

after passing between the roll 64 and the roll 95 cooperating therewith, will be found to be satisfactorily flattened. The control of the fluid supplied to the

cylinders

62 and 69 has not been illustrated since it may be of any desired character, automatic or manual.

Figure 1A illustrates a modified form of actuating mechanism for the guides 36. This means takes the form of pistons 10 reciprocable in cylinders II by means of fluid pressure, hydraulic or pneumatic, supplied thereto. The pistons I have piston rods I2 attached thereto corresponding to the screw shafts 33 and functioning in the same way, under the influence of fluid pressure admitted to either side of the cylinders H for actuating the guides.

A modified form of construction of the auxiliary rolls for feeding and flattening the strip is shown in Figures through '7. A roll table I3 has side frame castings I4. Housings 15 are attached to the castings I4 and have windows 16 therein in which bearing chucks 11 are slidable. Cylinders 18 formed in the upper part of the housings I5 have pistons 19 reciprocating therein. Piston rods 80 attached to the pistons I0 are threaded.

into the chucks 'I'I whereby the latter may be lifted to the dotted line position shown in Figure 5. Piston rods 80 extend outwardly through the upper end of the cylinders I8 and are connected by cross beams 8|. Cylinders 82 carried on a transom 83 extending between the housings, also have pistons and piston rods arranged as shown in Figure 6 whereby the beams ill and, therefore, the chucks I'I, may be raised through a small distance. The piston rods of the cylinders 82 have separable, abutting engagement with bolts 8Ia. It will be apparent that the cylinders I9 and 82 provide independent means ,for lifting the chucks 11 through a long stroke and a short stroke, respectively. The object of this arrangement will become apparent as the description proceeds.

An equalizing shaft 84 extends betweenthe housings I5 and is journaled therein. Cranks 85 keyed to the shaft 84 carry trunnions 86 in slidable bearings blocks 81. The trunnions 86 are th aded into the chucks 11, as best shown in Figure 6. effect simultaneous and equal movement of both bearing chucks and prevents binding of the reciprocating mechanism.

A top pinch roll 88 is journaled in the chucks TI for cooperation with a bottom pinch roll 89, which-may conveniently be one of the rollers of the table 13. Flattening rolls 90 and 9I are also journaled in the chucks TI. The roll 9I cooperates with a roll of the table 13. A roll 92 is journaled in chucks 93 slidable vertically in the base The equalizing shaft obviously serves to portions of the housings I6. Cylinders and pistons 94, bell crank linkage 95 and struts 98 are provided, as shown in Figure 5 to effect vertical movement of the chucks 93 for a purpose which will appear later.

As best shown in Figure 7, the roll 90 is journaled inchucks 91'secured to the chucks H. A contact-actuating rod 98 is threaded into a projection 99 from one of the chucks 98. The rod 98 also passes through guides I00 projecting from one of the chucks 91. The rod 98 controls the engagement of a moving contact II" with a fixed I contact I02 on one of the chucks 11 for a purpose which will presently appear.

The chucks 93 are normally lowered so that contact IOI engages contact I02. These contacts control a circuit for stopping the main mill motor in case of breakage of the strip. When the strip is being rolled, the

rolls

88, 90 and 9| rest on .the strip and are spaced thereby from the

rolls

89 and 92. After the strip has been entered into the mill so as to separate the pinch rolls 88 and 89, fluid is admitted to the cylinders 94 to cause the chucks 93 to be raised until the roll 92 engages the lower surface of the strip. The rolling operation then proceeds. If breakage of the strip should occur, the continuing fluid pressure in the cylinders 94 causes the chucks 93 to rise until theroll 92 actually engages the roll 90. This causes the rod 98 to move upwardly and lift contact IOI out of engagement with contact I02. Separation of these contacts, through suitable auxiliary equipment, causes stoppage of the main mill motor.

The

cylinders

19 and 82 are automatically controlled to cause the pinch rolls 88 and 89 to engage the material at certain times and to release it at other times.

In rolling a slab into strip on the mill I0, it is desirable that the pinch rolls 88 be withdrawn as long as the slab being reduced has suiflcient rigidity to permit it to be fed back and forth to and from the mill by the friction .of the table rolls. When the slab has been reduced to a gauge such that it has relatively little rigidity, or to a condition in which coiling between passes is advisable, the pinch rolls are advanced to assist in threading the strip through the mill at the beginning of each pass. While both ends of the strip actually pass through the mill, the pinch roll motors are so controlled that neither end of the strip is disengaged from the pinch rolls on both sides of the mill. At least one end of the strip is always engaged by at least one set of pinch rolls. It is by these pinch rolls that the strip is then fed back to the mill for the next pass. On the exit side of the mill, the pinch rolls assist in delivering the leading end of the strip into the coiler by pushing it up the guide 22.

The system for automatically controlling the pinch rolls will be now explained with reference to Figure 8. In Figure 8, the work rolls of the mill are indicated by the same numeral as in Figures 1 and 2. A motor I03 is provided for driving the mill and the power of the motor may be applied directly to the work rolls I5 or to the backing rolls I4. The motor I03 may be controlled by any suitable control system. For simplicity, I have only illustrated a control panel I04 having incoming power leads, outgoing motor leads, and outgoing control leads extending to a controller I05. The panel I04, of course, will be provided with suitable relays and contactors effective under the control of the controller I05 to cause starting of the motor I 03.

The panel I08 alsohas a relay I08 effective when deenergized to cause stopping of the motor. The specific details of such an arrangement are known and need not be included here. The controller I05, obviously, is effective on being shifted manually in one direction or the other, to cause operation of the motor I03 to drive the mill rolls I5 and thus move the strip through the mill in the desired direction. The supply of fluid to the

cylinders

18, 82 and 98 is controlled by a master valve I01 and auxiliary valves I08 and I09. The valve I01 has operating magnets H0 and III and the valve is of such character that it remains in the position to which it was last operated until positively actuated therefrom. The valves I08-and I09 have operating magnets H2 and H8. The arrangement of these valves and their operating magnets is such that they remain in the illustrated position until the magnets are energized, and return to the illustrated position when the magnets are deenergized.

The valve I01 is controlled by a limit switch II4 operated by any convenient means, in accordance with the position of the mill screwdowns which determine the thickness of the pass between the rolls and the material itself after passing through the mill. When the space between the mill rolls I5 is greater than a predetermined value, say the limit switch Ill closes its lower contacts to energize the magnet III and move the valve I01 so that fluid under pressure is supplied from a reservoir II5 through suitable piping, to the cylinders I8 on both sides of the mill. The pistons 19 are thereby actuated full stroketo withdraw the upper pinch roll 80 and provide ample free space for the passage back and forth to and from the mill of the slab in the initial stages of its reduction to strip.

When the thickness of the slab has been reduced to a point such that, on the next pass, the mill rolls are spaced apart only or less, the partially reduced material is sufllciently thinned and elongated to permit of coiling and, at the same time, its rigidity is such that the assistance of the pinch rolls is required to manipulate it through the mill and into the coilers. The limit switch Ill then closes its upper contacts to energize the magnet H0 and operate the valve m to the illustrated position. This 'vents the cylinder 18 and the pistons 19 immediately drop to lower the pinch rolls 88 onto the material. The pinch rolls are driven by any convenient means, at the same peripheral speed as the rolls' I5, so as to cooperate therewith in moving the material back and forth.

If it is assumed for the sake of explanation that the breakdown'formed from flat rolling the slab was reduced on a pass from left to right, to a gauge'such that after the next reduction, it would be less than thick, as soon as the top roll I5 is lowered to within less than of the bottom roll, the described operation of the valve I 01 will take place and the .pinch rolls will seize the breakdown for the next pass from right to left. When'all is ready for this pass, the roller operates the handle of the conbe bridged just after the leading end of the breakdown being rolled passes between the rolls I5. The magnet II3 operates the valve I09 to admit fluid supplied through the valve I01 to the cylinders 82 on the entering side of the mill. The pinch roll 88 on that side is thus lifted from the material.

After a slightly longer time, the relay III operates to bridge its contacts II 'Ib, maintaining the circuit for the magnet II3 by reason of the fact that the bridging contact slides along the contacts Illa. The relay is adjusted so that the contacts IIIb are bridged after the material has emerged from the mill on the exit side, passed through the pinch rolls, and made one turn about the coiler. The bridging of the contacts II'Ib causes the operation of magnet III to shift the valve I 08. The cylinders 82 on the exit side of the mill thus operate to raise the associated pinch roll from the strip. The strip is thus free between the. winding and unwinding coilers, except where engaged by the mill. F

The operation of the valves I09 and I 08 described above, also causes the operation of the cylinders 94 on opposite sides of the mill. The roll 92 is thus raised into engagement with the material but is sufllciently spaced thereby from the roll 90 that the contact IOI remains in engagement with the contact I02. The fluid pressure is continuously applied to the cylinders,

94 as long as the rolling continues but, unless the strip breaks during rolling, the

rolls

90 and 92 are maintained separated and the contacts IM and I02 remain in engagement. If the strip is broken, the roll 92 is immediately lifted into engagement with the roll 90, whereupon the rod 98 lifts the contact IOI to open the circuit for the relay I08 and thereby stop the motor ,I08.

When the pass is completed, the controller I 05 is restored to neutral position so that the trailing end of the strip stops between the mill and the pinch rolls on the" exit side thereof. The relay II! is thus deenergized and substantially immediately opens its contacts to deenergize magnets H2 and H3. The cylinders 82 are thus exhausted to the atmosphere and the pinch rolls dropped. At the same time; the cylinders 94 are exhaustedthrough check valves II8, the weight of the roll 92 and chucks 98 serving to force the accumulated 'fluld out of the cylinders. The operating fluid for the cylinders 94 passes initially through expansion valves I I8 which slightly delays the lifting of the chucks 93 on starting a pass.

The next pass is accomplished in exactly the same manner. Reversal of the controller I05 energizes the relay I20 and this. in turn, causes sequential lifting of the pinch rolls 88 on the entering and exit sides of the mill. This cycle is repeated until the strip has been reduced to the desired gauge, when it is wound on a coller beyond the furnace on the exit side of the mill. The top work roll is then lifted by reversal of the screwdowns. The switch II4 closes its lower contacts and operates the valve I01 to admit fluid under pressure again to the cylinders 18, whereby the pinch rolls 88 on both sides of the mill are lifted out of the way for the next flat rolling operation.

Figure 9 shows how the side guide actuators of Figure 1A are controlled. When the controller I5 is shifted so as to cause the material to be fedfrom left to right, it closes contacts Hi. It

5 will be understood that operation of the controller also, through appropriate relays, causes the starting of the motor H13 in the proper directionr The closing of the contacts l2| energizes an operating magnet I22 for a valve I23.

10 This valve is similar to that shown at I01 01 Figure 8. The energization of the magnet I22 operates the valve to the position illustrated in Figure 9, in which it delivers fluid under pressure to the inner ends of the cylinders II on the exit I 15 (left-hand) side of the mill, and to the outer ends of the cylinders on the entering (right-hand) side of the mill. The guides 36 on the entering side are thus closed in, as indicated in Figure 9,

while-the guides on the exit side are opened to 20 permit tree passage of the'material as it emerges from the mill.

On the reversal o! the direction of rolling, for

the next pass, the controller I 05 bridges contacts its and energizes a magnet I25 to shift the valve 25 M3 to the other position. The reverse operation of the cylinder ii then takes place to close the guides on the left-hand side and open the guides on the right-hand side. It will be understood that only a single con 30 troiler m5 is employed and that it controls contacts Hit and H24, for example, simultaneously, in addition to the other contacts necessary to bring the motor Hi3 up to operating speed. The system of Figure 9 is shown separately from that 35 of Figure 8 simply because it is a diagrammatic plan, whereas the latter is a diagrammatic elevation, but it will be understood that the two systerns are combined and under the common control of the controller 9B5.

49 It will be apparent from the foregoing description that my invention provides a rolling mill having numerous advantages over known apparatus of the same kind. In the first place, the slab or strip is definitely guided into. the mill 45 along the pass line or longitudinal axis of the mill. There is thus no possibility for the strip to move into the rolls crabwise at a slight angle to the pass line. Cambering oi thestrip or slab is thus prevented. Free movement of the highly 59 flexible, thin strip from the mill is permitted without obstruction since the guides on the exit side at the mill are automatically retracted to form ataperlng guiding throat. The positions of the guideson opposite sides of the mill are re- 55 versed automatically with the reversal of the roll tables and the mill so that once the guides have been adjusted, they require no further attention until a different width ofmaterial has to be rolled. The flattening rolls insure that the leading end of the strip will always be sufficiently flat to enter and engage the coiler properly to wind the strip thereon. This avoids the delays experienced heretofore incident to'the backing up of the strip 65 and repeating the entry thereof intothe coiler after a first unsuccessful attempt.

The top and bottom guides 29 and 26 respectively, with the side guides 34, form a complete guide box and prevent any departure of the strip 70 from the pass level or the horizontal plane through the roll passf With the guides of my invention, improper entry of the material into the mill is rendered almost impossible. The top guide may be adjusted by a turnbuckle in the 75 links 32. The bottom guide may be similarly adone side ofthe mill, and means for raising one of justed by shimming up the outer end thereof which rests on the seat 28.

The automatic control of the pinch rolls on both sides of the mill insures that the strip will be advanced properly into the mill and, on emerging therefrom, into the coiler, whereupon the pinch rolls will be lifted out of the way when there is no further need for them. The automatic stop mechanism prevents loss, damage or injury in case the strip breaks during a pass. 10

The positive actuation of the side guides under the control of the main controller causes the strip to be properly started toward the mill and correctly sitioned with respect thereto before it actual enters between the mill rolls, aiter which no efiort is suflicient to correct an improper starting of the strip, because of'the great force exerted on the strip by the rolls.

The top guide 29 has an important function in preventing the coiling up of the leading end 01' the piece when rolling in the flat. I! it were not for this guide, the slab, in the early stages of its reduction, might bend up sufliciently'to escape the side guides altogether, whereupon it might be improperly entered into the mill pass on the next reversal.

Although I have illustrated and described only one embodiment of my invention, it will be ap parent that numerous changes therein may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim: l

i. In a rolling mill, side guides extendin therefrom, pivoted supports for the outer ends of the guides, means for adjusting said supports toward or away from each other, a roll table for feeding material to" and from the mill, and means driven from a roll of said table for moving the inner ends of the guides toward and away from each other.

2. in a rolling mill, a pair of side guides pivotally supported adjacent their outer ends, axialiy movable screw shafts hinged to the guides adjacent their inner ends, a roll table for moving material to or from the mill, means for shiiting said screw shafts including nuts thereon, means for driving the roll table, and means including a friction clutch whereby said drive I also actuates said nuts.

e. The combination with a hot strip mill and a collar adapted to receive stripirom the mill and wind it intoa coil, of means between the mill and the coiler for flattening the leading end of the strip passing from the mill to the coiler.

- e. The apparatus defined by claim 3 wherein" said-flattening rneans comprises a plurality of leveling rolls.

5. In a method of making strip, the steps ineluding rolling down a hot slab into an elongated strip, coiling the strip between rolling passes, o and flattening the leading end of the strip before coiling between passes.

6. In a rolling mill including a pair of housings and work rolls journaled therein, pinch rolls on the pinch rolls through a short distance, andindependent means for raising thev upper pinch rolls through a greater distance.

7. The combination with a rolling mill, of 7 pinch rolls on one side of the mill, one of said rolls being retractibie, a motor for driving the mill, a controller for the motor, and-means operated by said controller for causing retracting movement of said one oi. said pinch rolls at a predetermined time after the starting of the mill motor.

8. The combination with a rolling mill, of pinch rolls on at least one side of the mill for feeding material thereto, one of said pinch rolls being retractible, and means actuated by the setting of the mill for passes of various thickness, whereby to operate said retracting means.

9. The combination with a rolling mill having an adjustable upper roll, of pinch rolls for feeding material to the mill, one of said rolls being retractible, and means operated in accordance with the adjustment of the upper mill roll for controlling retraction of said pinch roll.

10. The combination with a rolling mill having a driving motor and a controller for the motor, of adjustable side guides on both sides of the mill, and means operated by said controller for shifting the guides inwardly on the entrance side of the mill and outwardly on the exit side of the mill.

11. The combination with a rolling mill and a roll table for feeding material thereto, a motor for driving the mill, of a pair of pinch rolls adapted to engage material on the table, at least one of said pinch rolls being movable, means for constantly urging said movable roll into engagement with the material, and means actuated by movement of said movable roll toward the other of said pinch rolls for stopping said motor.

12. The combination with a rolling mill having a driving motor, of a pair of pinch rolls adapted to engage the material moving to or from the mill, one of said rolls being movable,

- means for normally holding said movable roll in engagement with the material, and means actuated by movement of said one of said rolls into engagement with the other of said rolls for stopping said motor.

13. The combination with a rolling mill, a driving motor therefor and a controller for the motor, of pinch rolls on one side thereof, one of said rolls being movable, means tending to hold said movable roll against the material being rolled, and means responsive to movement 01' the roll on breakage of the material for stopping the mill motor.

14. The combination with a rolling mill, a driving motor therefor and a controller for the motor, of pinch rolls on one side thereof, one of said rolls being movable, means tending to hold said movable roll against the material being rolled, means responsive to movement of the roll on breakage of the material for stopping the mill motor, and means operated by movement of the controller to start the motor, for rendering said first-mentioned means efiective.

15. The combination with a reversing strip mill, and pinch rolls on opposite sides thereof for feeding material to and from the mill, of a pair of side guides on each side of the mill between the mill and the pinch rolls, means pivotally supporting the outer ends of said guides for swinging movement in a horizontal plane, and means for so moving the inner ends thereof as to dispose the guides on the entry side of the mill in parallel relation and those on the exit side of the mill at an angular relation, depending upon the direction oi' movement of the material through the mill, said first mentioned means being so spaced as to permit the strip to pass freely between the ends of the guides on the exit side and enter the pinch rolls.

16. In a strip mill, a controller for reversing the direction of rotation of the mill, side guides pivoted adjacent their outer end, and means operated by said controller for adjusting the inner ends of the guides toward or away from each other, according to the direction of rotation of the mill.

17. In a strip mill, 9. pair of side guides on each side of the mill, pinch rolls adjacent the outer ends of the guides and means controlled by the direction of movement of material passing through the mill eflective to cause the guides on the entering side to move to parallel relation, and those on the exit side to move to an angular relation forming a tapering throat with its narrowest portion adjacent the pinch rolls whereby accurately to center thematerial entering the pinch rolls and preventing cambering of the material.

18. In a rolling mill, a pair of housings having work rolls journaled therein, pinch rolls on at least one side of the'mill for engaging material being worked in the mill, means for retracting one of said pinch rolls when unused for a substantial period, and independent means for temporarily retracting-one of said rolls.

19. The combination with a rolling mill and a roll table for advancing work thereto, of pinch rolls on one side of the mill, one of said pinch rolls being retractible, and means for retracting said roll including fluid pressure-operated cylinders and pistons, one of which has a short stroke for temporarily retracting the roll and the other having a longer stroke for retracting the roll when .unused for substantial periods.

20. Strip rolling apparatus comprising a mill, pinch rolls on opposite sides thereof for feeding material to and from the mill, guides between the mill and the pinch rolls, and means for positioning the guides on the entering side of the mill parallel to the pass line whereby to guide positively the material advancing to the mill, said means being also eilective to set the guides on the exit side at a slight angle tov the pass line forming a converging throat to receive material issuing from the mill and guide it into the pinch rolls while maintaining it centered relative to the pass line.

ALONZO B. MONTGOMERY.