US1814354A - Metal rolling mill screw down control - Google Patents

Description

July 14, 1931. w. R. WEBSTER ET AL 1,814,354

7 METAL ROLLING MILL SCREW DOWN CONTROL Filed Dec. 15, 1928 2 Sheets-$heet l WM Q M MIMI' July 14, 1931. w. R. WEBSTER ET AL METAL ROLLING MILL SCREW DOWN CONTROL 2 Sheets-Sheet 2 Filed Dec. 15, 1928 Patented July 14, 1931 WILLIAM R. WEBSTER AND WALTER R. GLARK, OF BRIDGEPORT,

CONNECTICUT METAL ROLLING- .MILL SCREW DOWN CONTROL Application filed December 15, 1928. Serial No. 526,333.

Our invention relates to a method of and of uniform hardness and temperature, and apparatus for rolling metal, and more parthe temperature of the rolls remains conticularly to a method of and apparatus for stant, then the size of the pass can be adreducing metals and other materials to justed to bring about the desired reduction v sheets or strips of uniform gauge or thickand no changes or adjustments thereafter ness. will be necessary. We have found, however,

The usual means for reducing metals and that when material of greater or less thickother materials to sheets or strips comprises ness or gauge, or of variable hardness, is dea plurality of mills arranged in tandem, livered to the mill the gauge of the material 0 each mill consisting of two or more metal delivered by the mill varies regardless of reducing rolls, the metals or other materials the fact that no apparent change takes being passed between the reducing rolls of place in the size of the pass between the rolls the mills successively, each mill reducing the of the mill. This is chiefly due to the fact thickness or gauge of the materials a certhat in rolling materials the spring or elas- 15 tain amount until the sheet or strip emerges ticity of the mill itself is such that variafrom the last or final mill with the desired tions in the gauge of the material entering thickness or, gauge. persist, in like variations of gauge in the The gauges of sheets or strips of material material leaving the mill in a more or less delivered by a final mill of a series must be fixed percentage rate, while where the ma- 20 kept constant within very narrow limits in terial is of variable hardness the resistance order to meet the standard gauge variations offered to the rolls of the mill varies, with allowed by the trade, and in order to bring resulting changes in the gauge of the mathis about the several causes of gauge variaterial delivered.

tions must be kept constantly under control. It is, in general, an object of the present There are four major causes of gauge variainvention to provide a method and means for tions in the rolling of materials in a rolling controlling the amount of reduction brought mill; first, that due to variations in the about by a rolling mill, in0rde r to deliver gauge of the materials entering between the material from the mill having a uniform and rolls of the mill; second, that due to variaconstant gauge or thickness. 7

tions in the hardness of the material being In a more specific aspect, it is an object rolled; third, that due to variations in the of the present invention to provide a methroll temperatures; and fourth, that due to 0d andmeans for compensating for changes changeskin roll contours during the rolling in the amount of spring ta 'ng place in a processes. mill due to differences in the amount of re- Of the several causes of gauge variations, duction which takes place in the material we shall concern ourselves chiefly in the prespassing through the mill. ent application with those due to variations A further object of the invention is to in the gauge of material entering between provide means for constantly gauging the the rolls of a mill and to variations in the material acted on by a rolling mill and open 40 hardness of the materia ing or closing the pass between the rolls ac- In the usual mill for rolling metal there is cording to the gauge of the material.

provided means for varying the size of the A still further object of the invention is pass or opening between the metal reducing to provide a mill in which the size of the rolls, and the mill operator constantly pass or opening between the metal reducing measures the thickness of the material derolls may be adjusted when the material livered by the mill and adjusts the size of starts to pass through the mill, and in which the pass or opening, in order to correct any the gauge of the material will thereafter be variations which take place in the gauge of kept C n n Without further lltiOIl 011 the material delivered. If the material dethe part of the operator.

livered to the mill is of a constant gauge and T0 t ese and other ends, the invention 1m novel features and combinabe hereinafter described and consists in the tion of parts to claimed.

In the drawings,

Fig. 1 is a side elevation of a rolling mill showing a preferred form of our invention used in connection therewith;

Fig. 2 is an end view of the same Fig. 3 is a view of a device used for gauging the material acted on by the mill; and

Fig. 4 is a view of an electric circuit used in connection with the controlling device.

In the above description of the nature and objects of our invention, we have referred to the usual arrangement of mills in a tandem in metal reducing, and while our invention may be carried out with such an arrangement of mills it is by no means limited thereto but is of equal utility in instances where but a single reduction of the material takes place, as for example, where it passes through a single mill.

It will be also understood that our invention is not limited to a mill or mills having any particular type or arrangement of rolls therein, and thus while we shall describe our invention in connection with a two-roll mill, which is one of the simplest forms of mills in use, it will be understood by one skilled in the art that the invention may be carried out with cluster mills, four-high mills, and various other forms.

Referring then to the drawings in which we have shown a preferred embodiment of our invention, the reference numeral 10 indicates, in general, a mill stand or frame, having mounted therein a lower rollijll and an upper roll 12, the lower roll being mounted in relatively fixed bearings 13, while the upper roll is mounted in adjustable bearings 14.

The material being acted on by the rolls 11 and 12 enters between these rolls at A with an initial thickness T and emerges from between the rolls with a final thickness T the amount of reduction being the difference between these two thicknesses. It will be understood that in practice a plurality of mills, such as that shown in Fig. 1, may be provided and arranged in tandem, and that the material may pass successively through these mills, each mill reducing the material a predetermined amount. The amount of reduction brought about by each mill depends primarily upon the size or opening of the pass between the metal reducing rolls of the mill, and where a tandem of mills is used the operator adjusts the rolls of the various mills of the tandem by hand to bring about a desired amount of reduction in each mill, being guided in controlling the amount of reduction by the character of the material being acted on by the mills and the desired guage in the material emerging from the mills.

In order to ensure that the material passes from each mill with the desired gauge, and in order to avoid the usual hand controlled methods for controlling the amount of reduction which depend for success of an operator, we propose to control the size of the pass or opening in the mill, or tandem of mills, by suitable means, the operation of which is controlled by the thickness or gauge of the material acted on. \Ve prefer to control the size of the pass of a mill by means which is controlled by the thickness or gau e of the material as it leaves the mill. I n carrying out our invention, we provide power means for adjusting the sizes of the passes in a mill or mills, which may be in the form of hydraulic motors, electric motors, or other suitable prime movers, and control the operation of these means by a device which gauges the material passing from the mills. As a suitable and preferred means for carrying out our invention, we shall now describe a mill in which the size of the pass is controlled electrically.

Referring again to the drawings, the reference numerals 15 and 16 indicate adjusting screws mounted in threaded openings in the upper ends of spaced frame parts 17 and 18, screws 15 and 16 being provided with noncircular ends 19 and 20, for the reception of a wrench, by means of which the screws may be adjusted in frame 10 to move the roll 12 towards oraway from roll 11. Mounted on the upper ends of frame parts 17 and 18 are brackets 21 and 22, provided with bearings 23 and 24 for screws 15 and 16, bearings 23 and 24 being spaced from the upper ends of frame parts 17 and 18.

Between bearing 23, on bracket 21 and the adjacent upper end of frame part 17, is a rotatable sleeve 25 mounted on and surrounding screw 15, sleeve 25 being provided with a screw 26 having an inner end 27, received in a longitudinally extending slot 28 in screw 15. On the lower end of sleeve 25 is a worm wheel 29 having in engagement therewith a worm 30 mounted on the shaft 31 of reversible electric motor 32, shaft 31 of motor 32 extending transversely of frame 10 and having mounted on the opposite end thereof from motor 32 a second worm 33 in engagement with a worm wheel 34 mounted on the lower end of sleeve 35, which is received on screw 16, below bracket bearing 24 and is provided with a screw (not shown) similar to screw 26 in sleeve 25, which similarly engages a longitudinally extending slot in screw 16. It will be readily understood without further description that upon rotation of motor 32, sleeves 25 and 35 are rotated, thus producing rotation in screws 15 and 16, through the medium of screws 26 and longitudinally extending slots 27, the connection between sleeves 25 and 35 and upon the skill screws 15 and 16 by means of screws 26 and slots 27 permitting longitudinal movement of screws 15 and 16 relatively to sleeves 25 and 35.

Generally speaking, we propose to provide means for constantly gauging the material passing from the mill or mills, and controlling the operation of the motor provided for adjusting the rolls by suitable connections with the gauging means.

A suitable and preferred arrangement for this purpose is shown in Figs. 1, 3 and 4 of the drawings, being designated generally by the reference character 36, and comprising gauging device 37, which controls the operation of switch 38, the latter being connected by suitable electrical connections 39- to motor 32.

Gauging device 37 comprises a pair of arms 40 and 41 pivotally connected together at 42, and having on their opposite ends from pivot 42 a pair of gauging rolls 43 and 44, between which the strip or sheetof material passes as it emerges from between the rolls of the mill. Mounted on'arm 40 is a collapsible bellows or sylphon 45 filled with a suitable liquid which will conduct electricity, such as a salt water solution, and bellows 45 being connected by means of pipe 46 to liquid switch 38 which, in general, may be made of a tube 47 of glass or other suitable insulating material, and which is provided with oppositely disposed sealed-in contacts 48 and 49, above which are mounted another pair of oppositely disposedsealed-in contacts and 51. Arms 40 and 41 are urged together by relatively stiff tension spring 52, which is connected to arms 40 and 41 in any suitable or preferred manner. Mounted in a threaded opening in arm 41 is an adjusting screw 53, having a ball point 54 bearing against the upper part of sylphon 45, sylphon 45 being provided with a filling plug 55. y

In order that the gauging device maybe sensitive to small changes. of the material passing between the gauging rolls, it is proposed toprovide a sylphon which has a cross-sectional area may times greater than the cross-sectional area of the liquid switch. For example, if the area of the bellows is one thousand times the area of the bore of the tube 47, a movement of the top of the bellows of .001 of an inch will move the surface of the liquid in the tube one inch. Accordingly, if the terminals 48 and 49 are spaced a distance of one inch from terminals 50 and 51, a very small movement of roll 43 relatively to roll 44 will produce suflicient movement on the part of the liquid column to control the passage of an electric current between the terminals. Normally, when contacts 48 and 49 are submerged in the liquid and contacts 50 and 51 are above the liquid, the motor will be at in the thickness rest and the rolls of the mill will remain at a constant relative adjustment.

If the material discharged by the rolls of the mill becomes of increased gauge, it is apparent that rolls 43 and 44 will be separated from one another, permitting the level of the liquid in tube 47 to drop and opening the circuit in which the contacts 48 and 49 are connected, this circuit being such that through a relay the main switch controlling the operation of motor 32 is closed, bringing the motor into rotation, and through the medium of sleeves 25 and 35 producing rotation in screws 15 and 16 and movement of the rolls towards one another, thus reducing the gauge of the material as it emerges from the rolls and permitting the rolls 43 and 44 to approach one another, whereupon the liquid rises in tube 47 until it again closes a circuit in which contacts 48 and 49 are placed, opening the main switch and stopping the motor. In case the, gauge of the material becomes less than it is desired, the rolls 43 and 44 approach one another, thus forcing the liquid out of sylphon 45 and into tube 47 until it bridges the gap between contacts 50 and 51, which through a suitable relay close another main switch, which causes the operation of motor 32 in a reverse direction, and finally the'separation of rolls 11 and 12 to bring about a greater gauge of the material discharged from between the rolls.

The mill may be set to deliver material of a particular thickness by placing a piece of material of the desired thickness between rolls 43 and 44, and then adjusting screw 53 until the liquid in tube 47 is midway between contacts 48 and 50.

When the area of the sylphon is one thousand times the area of the bore of the tube and the terminals are placed one inch apart in tube 47, a variation in the material pass ing between the rolls 43 and 44 above or below a desired thickness sufficient to bring about a movement of .0005 at the top of the bellows will cause the actuation of motor 32 to readjust the pass between rolls 11 and 12 to bring the thickness of the material back to that desired.

Any suitable form of relays and-main switches for causing the actuation of the motor in reverse directions may be provided, that shown in Fig. 4 forming an etlicient means for this purpose. Referring then to Fig. 4, the reference numerals 56 and 57 indicate a pair of main line wires leading to anysuitable source of electrical energy, wire 56 being connected by lead 58 to terminal 59 of switch 60, and to terminal 61 of switch 62. Main line wire 57 is connected by lead 63 to terminal 64 of switch and terminal 65 of switch 62. 66 of switch 60 and terminal 67 of switch 62 are connected by a common lead 68 to Terminal flow of current throug voltage line wire 88,

motor 32, while terminal 69 of switch and terminal 70 of switch 62 are connected by a common lead 71 to motor 32. Switches 60 and 62 are operated by means of solenoids 72 and 73, respectively, and are each normally maintained in open posit-ion by means of springs 74 and 7 Solenoid 72 is provided with a lead 76 connected to one wire 77 of the low voltage line, while solenoid 7 3 is supplied with a lead 78 connected to lead 76, and likewise to low voltage wire 77. The other lead 79'from solenoid 72 is connected to a terminal 80 of relay switch 81, while the other wire 82 of solenoid 73 is connected to a terminal 83 of relay switch 84.. Terminal 85 of relay switch 81 and terminal 86 of relay switch 84 are connected by a common lead 87 to wire 88 of the low voltage line. Relay switch 81 is normally held in open position by means of spring 89, while relay switch 84 is normally urged into closed position by means of spring 90, relay switch 84 being held in open position by means of solenoid 91, which is connected to contacts 48 and 49 in switch 38, these contacts being normally bridged by the liquid in switch 38, and permitting the lead 92 connected to wire 77 and through the lead 93 connected to wire 88, lead 93 passing to switch contact 49, while contact 48 is connected to solenoid 91 by means of lead 94. Relay switch 81 is closed by means of solenoid 95, which is connected to low voltage line wire .7 7 by means of lead 92 and to contact 50 by means of lead 96, contact 51 being connected to the low voltage line wire 88 by means of lead 97 It will be readily understood that, when the liquid in tube 47 is of sufficient height to bridge the gap between contacts 48 and 49, current flows from lead 93 from low through the switch 38 and lead 94 to solenoid 91, and thence through lead 92 to low voltage line wire 77, thus energizing solenoid 91 and holding switch 84 in open position. WVhen the level of the liquid in tube 47 falls below contacts 48 and 49, the circuit leading to solenoid 91 is opened, thus permitting spring 90 to close switch 84 and permitting the flow of current through solenoid 73, energizing the latter and causing switch 62 to close, thus permitting current to fiow through motor 32 and to produce rotation in screwslzi and 16 to cause an approaching movement between rolls 11 and 12.-

If the liquid level in tube 47 rises high enough to bridge the gap between contacts 50 and 51, the circuit leading to solenoid 95 is closed, thus energiznig solenoid 95 and causing the closing of switch 81, which permits current to flow through solenoid 7 2 to close switch 60, which in turn permits the flow of current into motor 32, the flow of current in this case being in the reverse direction and producing movement in motor 32 in the reverse direction to cause rotation in screws 15 and 16 to bring about the separation of rolls 11 and 12 until the gauge of the material delivered by the mill becomes normal, whereupon the level of the liquid in tube 47 falls and opens the circuit. esired, a double throw double pole reversing switch 98 may be provided in the main line for causing the actuation of motor 32 by hand, while a single throw double pole switch 99 may be provided in the low voltage line for interrupting therethrough.

From the above description of the nature of our invention and the preferred means for carrying it out, it will be seen that we have provided a means for constantly gauging the thickness of material emerging from between the rolls of a mill, together with means for causing adjustment of these rolls to correct variations in the gauge of the material as these variations may occur. The preferred embodiment disclosed herein is capable of working within varying limits, it being possible with a large ratio between the areas of the sylphon and liquid to correct extremely small variations in the gauge of the material. Thus it will be seen that we have provided a method and means whereby a rolling mill may be set to deliver material of a particular gauge, and in which variations in the thickness or hardness of mate-' rials delivered to the mill are automatically compensated for, so that the material emerges from between the rolls of the mill with a constant gauge.

While we have shown a ment of our invention, it is to be understood that the same is not to be limited to all the the flow of current details shown but is capable of modification and variation within the spirit of the invention and the scope of the appended claims.

What we claim is:

1. In a gauge controlling system for a rolling mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by a reversible electric motor, the combination of means for engaging the material being. rolled on opposite sides thereof, a fluid chamber on said means, a liquid level operated reversing switch for said motor connected to said fluid chamber, and means on said material engaging means cooperating with said fluid chamber for controlling the liquid level in said switch.

2. In a gauge controlling system for a rolling mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by a reversible electric motor, the combination of a pair of arms pivotally connected together, means on said arms for ena 'ing the material on opposite sides thereswitch, and a connection between said bel-' with the liquid .level operated reversing switch for controlling said electric motor, a connection between said fluid chamber and reversing switch, and means on said arms cooperating with said fluid chamber for varying the liquid level in said reversing switch.

3. In a gauge controlling system for a rolling mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by a reversible electric motor, the combination of a pair of arms pivotally connected together, material engaging rolls on the ends of said arms, means for urging said rolls into contact with opposite sides of the material, a collapsible bellows on one of said arms, an adjustable element on the other of said arms in contact with a part of said bellows, a liquid level motor controlling lows and switch.

4. In a gauge controlling system for a rolling mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by power operated means, the combination of liquid level means for controlling the operation of the power means, and means for varying the liquid level in accordance gauge of the material acted on by the rolls.

5. In a gauge controlling system for a rolling mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by a reversible electric motor, the combination of a liquidlevel controlled switch forcontrolling the operation of said motor, and means for varying the liquid level in said switch according to the gauge of the material acted on by said rolls.

6. In a gauge controlling system for a rolling mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by a reversible electric motor, the combination of a pair of relatively movable members between which material may be received to be gauged, a liquid chamber on one of said members, means on the other of said members cooperating with the liquid contents thereof according to the gauge of the material received between the members, and a second liquid chamber connected to said first named chamber, the liquid level in said second named chamber being controlled by the amount of liquid retained in the first named chamber, and means controlled by the liquid level in said second named chamber for controlling the operation of the motor.

7 In a gauge controlling system for a 1 011% ing mill wherein the size of the pass between a pair of metal reducing rolls is adjusted by a reversible electric motor, the combination of a pair of relatively movable members between which material may be received to be gauged, a collapsible liquid chamber on one of said members, said chamber being of relativcly large cross-sectional area, means on the other member cooperating with the liquid chamber to collapse the same to vary the liquid contents thereof according to the gauge of the material received between the members, and a second liquid chamber connected to said first named chamber, said second liquid chamber being of relatively small cross-sectional area, the liquid level in said second named chamber being controlled by the amount of liquid retained in the first named chamber, and means controlled by the liquid level in the second chamber for controlling the operation of the motor.

In witness whereof, we have hereunto set our hands this 13th day of December, 1928. WVILLIAM R. WEBSTER. WALTER R. CLARK.

Images