US1708185A - Plate-rolling mill - Google Patents

Description

April 9, 1929. D, MATTE] 1,708,185

PLATE ROLLING MILL feyo df fel' D. MATTE] April 9, 1929.

PLATE ROLLING MILL Filed Feb. l2, 1927 5 Sheets-Sheet /'efo Maffei April 9, 1929.

D. MATTEI PLATE ROLLING MILL Filed Feb. l2. 1927 3 Sheets-Sheet 5 INVENTOK DIEGO MATTE,

ATLOJNE Y Patented npr. 9, 1929.

UNITED STATES DIEGO MATTEI, OF GENOA, ITALY.

PLATE-ROLLING MILL.

Application led February 12, 1927. Serial No. 167,717.

The object of the present invention is an improvement in plate rolling mills.

It is known that the pressure used in rolling mills is a reaction pressure produced by the metal upon the rolls between which it is obliged to go. As this pressure depends upon the temperature of the metal and the amount of the reduction in thickness desired, if perchance the temperature is too low for that amount, fixed by regulating screws, the pressure may become so great as to cause the breaking of the rolls, and even of the housing. In order not to run that risk, the pressure is ordinarily kept low, thus impairing not only the volume of production, but

also the quality of the product, because obtained at a lower temperature as the rolling lasts longer. 'Another disadvantage of the reaction pressure in that the thickness of the plate at the rims is less than in the middle, owing to the double deflection of the rolls.

All these inconveniences may be avoided by the employment of an exterior positive pressure, instead of reaction pressure, ap-

plied to the rolls, because in the rst place no breaks are possible as the pressure on the rolls by the plate cannot exceed the positive pressure, and secondly the deiiection of the rolls being in the same direction, the thickness of the interposed plate will be the same throughout its breadth. Besides the strength of the rolls in the case of two rolls is doubled, and is very much increased if more rolls are employed, because they resist-j ointly, instead of separately as for the reaction pressure, and may be strengthened, if required, by the adoption of a bearing roll placed underneath the bottom roll. Pivots are only subjected to shearing if there is a bearing roll and therefore stronger. Regulating screws are no longer necessary and in their place is put a device that keeps the top roll always parallel. Rolls of smaller diameter may be used, which give, as it is known, much elongation and require less pressure, than the larger ones, and therefore power is spared, owing to less friction in the bearings. Finally with the adoption of a special electric devieethe rolling may take place quite automatically, under the best conditions, without fear of breaks of any kind.

The best and simplest way to give the pressure to the rolls is by a means of hydrau- 5 lic cylinders whose pistons work upon a kind of beam, which carries the bearings of two pressing rolls placed one on each side of the top roll of the mill. These rolls are made of pressing parts and of reduced portions alternately; the pressing parts of one roll must correspond with the reduced portions of the other roll, in order to avoid the formation of furrows or hollow places on the top roll. The number and position of the hydraulic cylinders is immaterial, provided that the beam be calculated and shaped in such a way as to transmit to the top roll a uniform pressure.-

In the drawings, Fig. 1 is a vertical cross section of a plate rolling mill embodying the invention; Fig. 2 is an elevation, partly 1n section of the same; Fig. 3 is a plan view of two pressing rolls as used in the rolling mill; Figs. 4 and 5 are schematic views showing the arrangement when three and four' hydraulic cylinders are employed; and Fig. 6 shows diagrammatically the means for app lying a positive pressure to the top working roll of the mill and for actuating the table reversing gear. Fig. 7 is a schematic view showing the electric operation of the pressure rolls and tables; and Figs. 8 and 9 are sections of the electromagnet-opcrated valves.

In the figures, (1) is the frame of the rolling mill in which are mounted the working rolls (2), and the bearing roll (3) as shown in Fig. 1. (4) represents a cross beam carried by the frame (1) and on which is mounted a hydraulic cylinder (5), said cross beam being secured to the connecting rods (6) of the frame (1) by means of iianges (7) and bolts (8) substantially as shown.

In the cylinder (5) is mounted a piston (9), the piston rod (10) of which engages a pressing beam (11) mounted in said frame and secured from transverse displacement by means of the guide pieces (11') contacting suitable projections on said cross beam Mounted one on each side of a vertical plane through the longitudinal axis of the top working roll (2) is a pair of pressing rolls (12) formed with portions thereof (13) reduced in diameter, the reduced portion (13) of one pressing r'oll (12) corresponding to the pressing portion of the other roll (12).

The pressing beam (11) engages the reduced portions (18) of the pressing rolls (12) and is so formed as to transmit a positive pressure, uniformly along the entire Working length of the top working roll, through the pressing rolls, when hydraulic pressure is exerted on the piston (9). (14) are toothed sectors keyed on two cross shafts (15) gearing with toothed bars .(16) fixed to the bearing of the top roll; this device has the purpose of ensuring a parallel motion of the top roll. (17) are levers carried by the lifting table of the plate, the upper end of these levers being provided with a kind of rounded head (18) projecting between two electric contacts 19) whose way of working is shown in Fig. 6. There are fourof these levers, two on each side of the rolls. (.25) is an hydraulic cylinder fixed to the housing, which through the connecting rod (26) and the crank (27) operates the cross shaft. (15) in order to bring the top roll to its higher position. l

Referring now to the Fig. 6 (20), (2O (21) and (21') are four levers as above described by (17 Fig. l; they touch the lower contacts (19) when there is no plate over them, and touch instead theupper contacts (19) when the plate passing over their heads 18) causes the levers to rotate. The levers (20') (21') must be so placed, that the plate is always at least on one of them. There are four electric circuits (I),. (II), (III) and (IV) each of them circulating in an electromagnet (I), (II), (III) and (IV) causing their respective cores, when they are closed, to be moved so as to open the communication by means of levers (20), (21) between the pressure (oil or water) and the cylinders and between the pressure and the table reversing gear by the two levers 20'), (21'). The electiomagnets (I), (II) act on the same core, therefore the pressure is shut-ofi' from the cylinders only when the plate is out of the two levers (20) (21) in other words the pressure is exerted on the cylinders a little before the plate is seized by the rolls, and removed a little after it has left the rolls. It follows that tlm plate end becomes tapered thus making the grip of the rolls easier, and allowing a greater reduction in thickness of the metal, than could be possible otherwise in respect to their` diameter. Another very simple electric device connected with a thickness indicator working in a similar way of the above described may be employed to shut-off the pressure from both the cylinders and the table reversing gear, as soon as the plate has attained the required thickness, thus i'eiidering the rolling completely self-acting.

Fig. 7 shows schematically the electric operation of the pressure rolls and the tables, the levers (17) and contacts (19) being omitted for the sake of clearness. In this figure, (42) represents a hydraulic pressure pump communicating, by means of pipes (30) with the liydraulic cylinder (5) through valve (43), and the hydraulic cylinders (40) through valves (44). The cylinders (40) actuate the tables (41) through suitable piston connections.

The construction of Valves (43) and (44) is shown in Figs. 8 and 9. Each valve is provided with a main conduit (45) and a plunger core (46) which fits in a chamber (47) and prevents the passage of liquid through said conduit when the core is in its normal position as shown in Fig. 8. Each plunger core is recessed as at (48) to permit the How of liquid through the conduit (45) when the core is in the raised position shown in Fig. 9. The core will be raised when currentl is passed through the respective electromagnet. (I), (II), (III) or (IV) as the case may be. A spring (49) is provided in each valve above the core so as to ensure the depression of the core when the electric circuit through the respective electromagnet is broken.

The making and breaking of t-he electric circuits through the electromagnets have already been explained, and it will not be understood how this making and breaking of the circuits controls the pressure of the working rolls and the action of the tables.

The use of a core of an electromagnet under the action of a current, has been given only as an example; but all the other effects due to the closure of an electric circuit, may be applied in order to obtain the above mentioned purposes; the most important thing is the arrangement of the circuits as it has been shown.

Having described my invent-ion, what I claim is 1. In a plate rolling mill, a plurality of vertically-aligned working rolls, and means for imparting a positive pressure only to the top working roll throughout its working length comprising a pair of pressing rolls located one on each side of a vertical plane through the longitudinal axis of the roll, and contacting with the roll throughout the woi'king length thereof, a pressing beam engaging said pressing rolls and adapted to exert a vertical downward pressure thereon, said pressing beam being so shaped as to receive the same deflection as the system of working iolls when the mill is in operation, a hydraulic cylinder carried by said beam a piston in said cylinder, and a piston rod connecting the piston to said pressing beam so that when hydraulic pressure is exerted on said piston, this pressure will be transmitted uniformly to' the top working roll throughout its entire woiking length.

2. rlhe structure recited in claiinl and means for raising the top working roll and to ensure the parallel motion thereof comprising a rack connected to each bearing of the said top Working roll, a toothed sector meshing with each rack, a shaft on which said sectors are keyed, a crank connected to said shaft, a connecting rod pivotally connected at one end to said crank, and a second hydraulic cylinder connected to the other end of said connecting rod for rocking said shaft by means` of said crank and connecting rod.

3. The structure recited in claim l together with electric means for exerting pressure on said piston in the hydraulic cylinder just before a plate being rolled is engaged by the Working rolls and removing said pressure just after the plate has left the working rolls, and electric means connected with said first mentioned electric means for effecting the reversing movement of the plate.

4. In a plate rolling mill, three verticallyaligned working rolls, a bearing roll below the lowest of said working rolls and Contact ing therewith, a pair of pressing rolls located one on each side of a vertical plane through the longitudinal axis of the top roll and contacting with the top roll throughout the working length thereof, a pressing beam engaging said pressing rolls and adapted to exert a vertical downward pressure thereon, said beam being of such a shape as to receive the same deflection as the system of working rolls when the mill is operated, a hydraulic cylinder carried by said beam, a piston in said cylinder, and a piston rod connecting said piston to said pressing beam so that when hydraulic pressure is exerted on said piston, this pressure will bev distributed uniformly to the top working roll throughout its entire working length, a rack connected to each bearing of the said top working roll, a toothed sector meshing with each rack, a shaft ou which the sectors are keyed, a crank on the shaft, a connecting rod pivoted at one end to the crank, and a .second hydraulic cylinder connected to the other end of said connecting rod for rocking said shaft by means of said crank and connecting rod so as to raise the top working roll as desired and ensure the parallel motion thereof, and means for exerting pressure on said piston in the firstmentioned hydraulic cylinder just before a plate is engaged by the working rolls and removing said pressure just after the plate has left the working rolls.

DIEGO MTTEIl

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