US3383898A - Continuous rolling mill - Google Patents

Description

May 21, 1968 l. PROPERZI CONTINUOUS ROLLING MILL Filed March 21, 1967 3 Sheets-Sheet 1 C INVENTOR.

May 21, 1968 1. PROPERZI CONTINUOUS ROLLING MILL 5 Sheets-Sheet Filed March 21, 1967 INVENTOR r f i BY a k jimka z May 21, 1968 l. PROPERZI CONTINUOUS ROLLING MILL Filed March 21', 1967 5 Sheets$heet 3 m v N w m 8 m /u f. E .L g I H n gt United States Patent 3,383,898 CONTINUOUS ROLLING MILL Ilario Properzi, Via Cosimo del Fante 19, Milan, Italy Fiied Mar. 21, 1967, Ser. No. 624,955 5 Claims. (Cl. 72-249) ABSTRACT OF THE DISCLOSURE A rolling mill assembly is disclosed, in which all idle gears have been dispensed with for transferring the motive force, thus affording the advantage of having gears of a larger diameter than in the prior art mills and of transmitting thereby larger amounts of motive power than heretofore practicable.

This invention relates to a continuous rolling mill, and more particularly to a train of rolls for metal rods and wires.

Several kinds of rolling mills for rods and wires are known in the art, which comprise a sequential array of adjacent rolling stands which contain the individual rollers, the individual stands being driven by shafts (one for each stand) arranged in alternation and at even distances above and below the rolling line and rotating in alternately inverted directions. In the conventional trains of rolls, the transfer of the drive from one of said shafts to the preceding or the next shaft is effected by inserting idle gears which engage spur gears keyed onto said shafts: the shafts are driven by a motor through a plurality of parallel axles carrying beveled gears which act on as many discrete gears fixed to said shafts.

Such a train of rolls is affected by serious shortcomings which emanate, in the first place, from the presence of the idle gears intended for transferring the drive from an actuating shaft to another of the adjacent roll stands. It is apparent, indeed, that, inasmuch as the distance between an actuating shaft and the next has a fixed and well defined magnitude, the diameters of the spur gears keyed onto the shafts can be but a fraction of the distance existing between two adjacent shafts or, stated alternatively, said idle gears and spur gears have, of necessity, small diameters. Since the rotational speed of the rolling cylinders (and thus of all the idle and active gears connected thereto is a fixed design datum for the rolling mill), the idle and active gears are rotated at a low surface speed on account of their small diameter, and are enabled to transfer small amounts of power only. The teeth of the idle and active gears should have a diametral pitch corresponding to the gear diameters, and thus are, of necessity, of reduced size, this fact being an additional reason why high stresses cannot be transferred from a gear to another gear coming in engagement there-with. With the conventional trains of rollers it is not possible, therefore, to transfer high powers (i.e., over 1,000 HP) as requested by the present-day technology in the production of metal rods and wires.

Another shortcoming of the rolling trains of conven tional make lies in that the multiplicity of idle drivetransferring gears requires a corresponding multiplicity of axles for supportng said idle gears and bearings therefor, thus having a negative influence on the initial cost of said trains of rollers.

A further shortcoming which isa result of the multiplicity of idle gears in the conventional rolling mills for metal rods and wires lies in that it is extremely awkward to place said trains in working order so as to obtain correct meshing of the gears with one another.

Still another shortcoming is a consequence of the fact that in the conventional trains of rollers, the drive is Patented May 21, 1968 transferred from the motor to the cylinders of the roller stands via bevelled gears (which are expensive and diflicult to set) borne by a plurality of axles actuated by the motor and acting, each, on a bevelled gear of a shaft which is an integral part of a set of roller stands. Thus, a train of rollers is made up by a sequential array of sets of roller stands, and the rollers are not all directly connected to the preceding and the next rollers, respectively.

An objective of the present invention is to overcome the drawbacks enumerated above, to provide a train of rollers for metal rods and wires (wherein a large number of roller stands is employed) which is capable of trans ferring powers over 1,000 HP and, more precisely, in the order of magnitude of 2,000 HP.

Another object is to provide a train of rollers which is adapted to be cheaply constructed and requires only a quick and convenient setting operation.

The foregoing and other objectives are achieved by a train of rollers comprising a driving motor and a plurality of sequentially arranged roller stands in which every one of said stands receives its drive from a single shaft and in which said shafts are arranged alternately at equal and opposite distances with respect to the rolling line, said train being characterized in that on said individual shaft of at .least each of the two end roller stands of said set of roller stand is keyed a single gear and that on said single shaft of the other stands is keyed a pair of gears of different diameters, one of the gears of said pair of gears of a shaft being in engagement with a gear of the next shaft, the other gear of said pair of gears of said shaft being in engagement with a gear of the shaft which immediately precedes said first named shaft, the gears being such that the roller stands have continuously increasing speeds in the direction of rolling, the motor shaft being connected to an axle which also has a pair of gears, one of said gears meshing with a gear of one of said shaft next thereto and the other gear meshing with a gear of one of said preceding shafts.

In order that the features of this invention may be better understood, an exemplary, non-limiting embodiment of the inventive continuous rolling mill for metal rods and wires will be described with reference to the accompanying drawings, wherein:

FIG. 1 is a front view of said train of rollers.

FIG. 2 is a partial plan view of said train of rollers, and

FIG. 3 shows a cross-sectional view of said train of rollers, taken along the line Ill-III of FIG. 2.

With reference to the drawings, said train of rollers comprises a driving motor 1, equipped with a fan 2 for cooling it, and a plurality of sequentially arranged roller stands 3, which are akin to stands known in the art and whose detailed description is omitted, each of said stands receives the drive through a joint 11 from a single shaft 4, the individual single shafts of each stand being arranged in alternation and equally spaced apart :but on opposite sides of the rolling lines. To each single shaft 4 of each of the two end stands of rollers is keyed a single spur gear, whereas to said single shaft 4 of the other stands of said plurality of stands is keyed a pair of spur gears 5 and 6 having different diameters. One of the gears of said pair of gears of each single shaft meshes with a gear of the pair of gears keyed to the next shaft downstream of said single shaft, whereas the other gear of said pair of gears of said single shaft is in engagement with a gear of the pair of gears keyed to the next preceding shaft.

The gears are such that the stands have speeds which continuously increase along the direction of rolling. This occurs because the cross-sectional area of the roller bar is decreased during progress of rolling so that the RPM of the roller stands should be increased so as to keep the rate of flow in the unit time, that is the volume of metal processed through each stand, a constant. The motor 1 is connected, by a joint 7, to an axle 8, placed in correspondence with the shaft 4 of one of the stands 3 and below it, two gears 9 and 10 being keyed to said shaft 4. One of said gears 9 and It) is in engagement with a gear of the pair of gears keyed to the shaft which is adjacent to and precedes the shaft placed above said axle 8, while the other of said gears 9 and 10 is in mesh with a gear of the pair of gears of the shaft adjacent and following the shaft placed above said axle 8. To the shaft placed above the axle 8 is keyed one gear only, this being in engagement with the other gear of the pair of gears of the shaft which is adjacent and on the left as viewed in FIG. 2, with respect to the shaft placed above the axle 8. The axle 3 is positioned in correspondence with the shaft of any stand of the plurality of stands 3, providing that said stand is not one of the end stands. In this latter case, it would be necessary to change the mode of meshing between said axle and the adjacent shafts. Furthermore, if the axle 8 of the motor 1 is placed at a point midway between the two ends of the train of rollers, the drive is transferred both upstream and downstream of said axle, As shown in FIG. 1, the stands 3 are assembled in a unit 12 and the shafts 4 with their gears 5 and 6 are assembled in a block 13, said blocks 12 and 13 being borne by a single bedplate 14. The block 12 has a perforation 15 through which the rod to be rolled enters or a rolled bar is delivered. If the axle of the motor 1 is rotated in the clockwise direction, the shafts 4 of the stands 3 are rotated in alternately reversed direction as shown by the arrows of PEG. 3 and the rod to be rolled enter-s through the hole 16 (FIG. 2), passes through the subsequent stands 3 and is then delivered, as rolled, from the hole 15. As shown in FIG. 2, all the gears are arranged on three parallel vertical planes.

A primary advantage which is obtained with the inventive rolling mill as compared with any conventional mill is to have done away with the idle gears. Since there is now more room available, the gears keyed to the single shafts 4 of the stands 3 can be made of a diameter larger than before, so that much more power is transferred than heretofer practicable with the conventional trains of rollers. As a matter of fact, the greater is the diameter of the gears, the greater is the surface speed thereof and consequently the transferred power is increased. Moreover, by increasing the diameters of the gears, the teeth can also be made thicker, which permit a further increase of the transferred power, In addition, by eliminating the idle gears the number of necessary gears is reduced, so that a safer operation is obtained together with an easier setting: in fact, if a great number of gears is involved, it is difficult to obtain that all of them may mesh perfectly. Lastly, elimination of the idle gears results in a considerable reduction of the initial cost of the rolling mill.

Another advantage is that in the train of rollers described above, the gears are not keyed to overhanging shafts but to shafts which are supported at both ends. This fact entails a greater simplification of the entire mechanism and thus a safer and long-lasting operation.

A further advantage is that only cylindrical gears are used, both spur gears and helical tooth gears which can be ground and replaced at a low cost. Thus, if a gear is broken, it is removed from its shaft and honed and, if the defect is serious, it is replaced without disturbing the train of rollers.

Finally, the fact that all the gears are arranged in three substantially vertical parallel planes gives a ready accessibility to the interior of the block 13 and thus the maintenance of said block is facilitated.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A rolling mill comprising, in combination, a plurality of consecutively arranged roll stands comprising each a -riven roll mounted on a single driven shaft and an idler roll, the driven shafts of successive stands being arranged parallel to each other and respectively to opposite sides of the rolling plane equally spaced therefrom; a single drive motor having a drive shaft parallel to said driven shafts and arranged intermediate the stands at opposite ends of said rolling mill; at first gear train for transmitting a drive from said drive shaft to the driven shafts on stands between said drive shaft and one end of said rolling mill; and a second gear train for transmitting a drive from said drive shaft to the driven shafts on the stands between said drive shaft and the other end of said rolling mill, each of said gear trains including successive pairs of meshing gears arranged alternately on opposite sides of said rolling plane mounted on said driven shafts of successive driven rolls and the gears of said first and said second gear train being constituted exclusively by gears respectively fixed to said drive shaft and said driven shafts for rotation therewith.

2. A rolling mill as defined in claim 1, wherein all said gears are spur gears.

3. A rolling mill as defined in claim 2, wherein said spur gears have different diameters arranged in such a manner that the rotational speed of said driven shafts increases from one to the other end of said rolling mill.

4. A rolling mill as defined in claim 1, wherein said gear trains comprise a single gear fixed to the driven shafts of the stands at opposite ends of the rolling mill and to the driven shaft on a further stand intermediate said opposite ends, a pair of gears fixed to each driven shaft of the remainder of said plurality of stands, a pair of gears fixed to said drive shaft, one meshing with one gear on the shaft of the stand preceding said further stand and the other meshing with one gear on the shaft of the stand following said further stand, and each of the pair of gears on the driven shafts of one stand, with the exception of said one gear on the shaft of the stand following said further stand, meshing with a corresponding gear on driven shafts of stands respectively immediately preceding and following said one stand.

5. A rolling mill as defined in claim 4, wherein the planes of symmetry of said gears normal to the axes thereof are respectively located in three parallel vertical planes.

References Cited UNITED STATES PATENTS 1,379,181 5/1921 Gore 72279 2,789,450 4/1957 Properzi 72-249 3,299,685 1/1967 Kooks et al 72-249 CHARLES W. LANHAM, Primary Examiner. RICHARD I. HERBST, Examiner.

H. D. HOINFES, Assistant Examiner.

. 323 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Datmi May 21, 1968 Patmm No. ,383,898

1 Ilario Properzi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, after the fourth line, the following line is inserted:

Claims priority, application Italy March 26, 1966, 16055 SIBNID AND RIM-ED mm mm GHQUQ .Auam

Ed a M. Fletch wmnu 1:. sum, :22. Attestlng Officer 0om1ss1oner of Patents

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