US3546915A - Drives for multistand universal rolling mills - Google Patents

Description

Dec. 15, 1970 J. sEvERlN E TAL y 3,546,915

DRIVES FOR MULTISTAND UNIVERSAL ROLLING MILLS Filed Oct 21, 1966 muil] l H mi llllll [lll IIHIIIUItI IIIIIIIIII| INVENIORS Jose Severin' 'B mm 2 A g. .n

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United States arent 3,546,915 DRIVES FOR MULTISTAND UNIVERSAL RLLDJG MILLS J ose Severin, Mulheim (Ruhr)-Speldrf, and Helmut Holthoi, Dusseldorf, Germany, assignors to Kommanditgesellschaft Friedrich Kocks, Dusseldorf, Germany, a corporation of Germany Filed Oct. 21, 1966, Ser. No. 588,367

Int. Cl. B211: 35/00 U.S. Cl. '72-249 2 Claims ABSTRACT F THE DHSCLOSURE A drive is provided for multistand universal rolling mills having successive roll stands in which the rolls are driven from a driving gear assembly adjacent the roll stands and extending the length of the mill, wherein the driven speed of each succeeding stand is developed from the speed of the preceding stand in one gear step and both parts of the continuous gear train are interconnected through an intermediate shaft.

This invention relates to drives for multistand universal rolling mills and particularly to wire rod or tube reducing rolling mills. Multistand universal rolling mills are not per se new, nor are -drive mechanisms for driving such rolling mills new in general terms. However, presently existing mills and their corresponding drives have been characterized by certain problems, particularly in the drive area, which the present invention successfully eliminates.

Multistand universal rolling mills for rolling e.g. wire rod and tube material are centrally driven in many cases. Driving power and speed of the rolling stands are imparted from a mechanical gear arranged e.g. by the side of the stands and covering the length of the rolling mill, the roll speeds of the subsequent stands corresponding at least essentially to the elongation of the rolling stock. The direction of rotation of the exit shafts to the stand changes from exit shaft to exit shaft. The exit shafts in such larrangements are arranged on a zigzag line or in a plane surface.

Rolling mills of this type are used for example, as the finishing train in a small section mill for rolling wire rod of g mm. The large total deformation on such a mill in connection with the entry speed of the rolling stock which must not be `diminished for cooling reasons necessitates in general a multistand rolling in the finishing train. It is intended to reach a delivery speed of the rolling stock as high as possible while working with as few as possible rolling strands, preferably with one rolling strand only, thus improving the exactness and regularity of the finished rolling stock and reducing the investment outlay-referred to the obtained production.

It is known to provide exit shafts for universal rolling mills equipped with a spur gear step from exit shaft to exit shaft, the gear ratio being equal in all steps or increasing from step to step in rolling direction. They are of simple construction and enable on each gear ratio in all steps a uniform elongation of the rolling stock in ice all roll passes, which is desirable in many cases. However, in such drive arrangements the highest obtainable exit speeds of the rolling stock are limited by the circumferential speed of the gear wheels of the exit end of the drive since the diameter of the gear wheels is dependent upon the spacing of the stands and the diameter of the rolls.

Drives for universal rolling mills are also known having a longitudinal shaft from which the exit speeds are taken through a bevel gear step. 4Since the bevel gear wheels cannot be manufactured with the same accuracy as spur gears such a drive does not permit a higher eXit speed of the rolling stock than is possible in case of the above spur gear drives.

Furthermore there is known in the prior art a wire rod drive with two -gear steps from exit shaft to exit shaft, thus the gear wheel diameter can be kept smaller than the spacing of the stand. In order to effect the reversion of the direction of rotation necessary from exit shaft to succeeding exit shaft, each second exit shaft is driven through an additional idler gear step Without a change in speed gear ratio. The expenditure of gear wheels and bearings is almost doubled as compared with the rst described drive.

Finally, it is proposed in a not yet published application to provide in the continuous one-step gear a speed ratio of 1:1 in all steps and to drive the driving shafts through a gear step gearing down on the entry end of the mill and gearing up on the exit end. Such a drive enables higher exit speeds of the rolling stock to be reached and the expenditure of gear wheels is less as compared to the case of two-step gears, but on the other hand it is not possible to reach with the same ratio of the number of teeth the same increases in the speed from one stand t0 the next. This drive is especially expedient for wire rod rolling mills.

An analysis of the known drives shows that high exit speeds of rolling stock necessitate the use of an excessive number of gears. In all of the above described drives, the gear step cycle is retained throughout the whole rolling mill so as to not disturb the position of the drives and the change of the direction of rotation in the successive exit shafts. Thus with the drives using more gears we have also more expenditure of gears with the exit shafts at the entry side of the mill without the speed of the rolling stock necessitating this.

lt is the purpose of the invention to provide a drive for universal rolling mills, especially wire rod and tube reducing rolling mills having several rolling stands arranged one behind the other in rolling direction for achieving higher exit speeds than can be reached with the use of a single one-step gear while avoiding the considerable constructional expenditure of gears of known drives.

We have solved the problem of prior art drives by providing a drive with a gear train extending the length of the rolling mill and arranged below, above or beside the rolling stands, from which the speed of the exit shaft of each subsequent stand is derived in one gear step from that of the preceding shaft the speeds of the last exit shafts in rolling direction being taken from the continuous gear train through an additional gear step gearing up the number of rotations, and both parts of the continuous gear train being interconnected through an intermediate gear particularly a common intermediate gear.

-In the drive according to our invention the gear drive is simplified by a single step gear arrangement at each shaft at the entry end of the mill. As to the exit part of the train Where the speeds are conveyed through a gearing up transmission, either the gearing up steps used in the entry side can be continued or the gear ratio in all steps can be 1:1. The additional gear step of each exit shaft has in one case the same gear ratio for all exit shafts or in another case is geared up from exit shaft to exit shaft.

The connection of both continuous entry and exit trains, especially by an intermediate gear, make possible the changing direction of rotation of the successive stands at the spot of transition and also makes it possible that the rolling mill can be driven centrally.

The shafts can be arranged either in a single plane or in a zigzag line as on two spaced parallel planes. Also the position of the intermediate gear is arranged in the division of the distances of the shafts when corresponding gear diameters are selected.

For a wire rod mill in which the roll diameter is large as compared with the diameter of the rolling stock and in which the elongation of the rolling stock in all roll passes is selected in general to be of equal size, an especially favorable execution of the drive can be obtained. All gear ratio jumps from exit shaft to exit shaft in the exit end part of the continuous gear train are selected to be equal and in accordance with the entry end part. Both gear trains are interconnected through an intermediate gear and the ratio of the number of teeth of the gears of the parts of the train meshing with this intermediate wheel is selected reciprocal to the exit end part of the drive.

This enables that the step jump from exit shaft to exit shaft, especially on the spot of transition, can be kept exactly since the efficient gear ratio of the both steps with the intermediate `wheel compensates that of the additional step. Also the number of wheel types is reduced to a minimum.

In a preferred embodiment of our invention, a drive for a multiple stand rolling mill is provided having generally parallel driving shafts driving the mill rolls in generally equally spaced vertical planes, a plurality of parallel shafts spaced from the said parallel driving shafts, said parallel driving shafts and plurality of parallel shafts lying in two parallel spaced apart generally parallel planes, one of said driving shafts being connected to an external drive means, at least one gear on each said parallel driving shafts and said parallel shafts, said gears being in mesh with one another to form a continuous gear train along the mill, the transmission being such that the speeds of rotation of each of the mill rolls increases in the direction of passage of material through the mill in rolling in proportion to the elongation of the material in the next preceding roll. Preferably the driving parallel shafts preceding said one shaft are provided with an identical driven gear and each such shaft other than the iirst is provided with an identical driving gear meshing with the preceding driven gear. The driving parallel shafts following said one shaft are provided with identical driven gears meshing with driving gears on said parallel shafts identical to the driven gears of the driving shafts preceding said one shaft and driven by a gear on the next preceding parallel shaft identical with the driving gears on the driving shafts preceding said one shaft.

A rolling mill can include several drives according to the invention, each drive driving only rolls of the same direction of the axis of each stand.

The invention will be better understood by reference to the following description and the accompanying drawings in which:

FIG. l is a schematic side elevational drawing of exit shafts on a zigzag line according to our invention;

FIG. 2 is a horizontal section through a drive according to FIG. l

FIG. 3 is a schematic side elevational drawing of exit shafts showing the arrangement of exit shafts on a straight line; and

FIG. 4 is a horizontal section through a drive according to FIG. 3.

Referring to the drawings, we have illustrated a housing 1 having an input coupling K through which driving power is introduced into the housing. Output shafts and couplings A-G inclusive extend out of the opposite side of housing 1 from input shaft K. The rolling direction is from left to right viewing FIGS. l and 2.

The first four output shafts and couplings A-D are driven directly from the continuous gear train made up of gears 11, 12, 13, 14, 15 and 16 in which gears 11, 13 and 15 are of the same size and gears 12, 14 and 16 are identical. The couplings E-G are driven through additional identical gear steps 31, 33, 35 along 'with direct gearing 2, 3, 4, 21,-22, 23, 24, 25. Gear 2 is identical with gears 31, 33 and 35, gears 3, 21, 23 and 25 are identical as are gears 4, 22 and 24. The axes of the output shafts are marked in full circles on the drawing, those of the auxiliary shafts by open circles.

The continuous gear train is formed in the entry end part by the gear ratios 11/12; 13/14; 15/16 and in the exit end part by the gear steps 21/22; 23/ 24; 25/ 26. The gear ratio jump is equal in all steps. Therewith also that of the additional steps in the exit end part 21/31; 23/33; 25/35 is equal in all steps.

The two continuous part trains are connected through the gears 2, 3, 4. In the illustrated drives the gears 11, 13, 15, 21, 23, 25, the wheels 12, 14, 16, 22, 24, and the gears 31, 33, 35 are equal among themselves, and the gears 2, 3, 4 are available only once each.

The step jump corresponds to the ratio of the number of teeth of the wheels 12 to l1 and is equal from output to output. The ratio of the number of teeth of the gears 4/2 meshing with the intermediate wheel 3 becomes equal to the reciprocal value of the ratio of the additional steps 33/22, the latter are not meshing. Actually, the speeds of the outputs D and E differ exactly by a step jump. This applies for the illustrated example in which the pinion of the additional step is driven by the large gear of the continuous sequence.

In FIGS. 3 and 4 we have illustrated a modification of our invention in which the exit shafts are on a straight horizontal line. The gear ratios, drive arrangements and the like are identical with those of FIGS. 1 and 2 and like parts 'bear like numbers with the suix a.

In the foregoing specification we have set out certain embodiments of our invention, however, it is to be understood that this invention may be otherwise embodied within the scope of the following claims.

We claim:

1. A drive for a multiple stand rolling mill ea-ch having mill rolls comprising generally parallel output shafts driving the mill rolls in generally equally spaced vertical planes, a plurality of parallel auxiliary shafts spaced from the said parallel output shafts, said parallel output shafts and plurality of parallel auxiliary shafts lying in two parallel spaced apart generally horizontal planes, one of said output shafts being connected to an external drive means, at least one gear on each said parallel output shafts and said parallel auxiliary shafts, said gears being in mesh -with one another to form a continuous gear train along the mill, said gear train being such that the speeds of rotation of each of the mill rolls increases in the direction of passage of material through the mill in rolling in proportion to the elongation of the material in the next preceding roll, said parallel output shafts preceding the said one shaft in the direction of rolling are driven by a single gear step of driving and driven gears and those following said one shaft being driven by a two gear Step connection of driving, and driven gears and an intermediate gear on one of said auxiliary shafts.

2. A drive for a multiple stand mill as claimed in claim 1 wherein each of the output shafts preceding the said one output shaft connected to an external drive lmeans is provided with an identical driven gear having an equal number of teeth and each such shaft other than the rst in the direction of rolling is provided with an identical driving gear meshing with said driven gear, each output shaft following the said one shaft is provided with an identical driven gear and each of the parallel auxiliary shafts except the r-st in the direction of rolling is provided with a driving gear identical with the driven gears of said output shafts preceding the said one shaft and engaging a driven gear on a parallel auxiliary shaft following said first parallel auxiliary shaft.

References Cited UNITED l/19l5 1l/1924 4/1957 12/1961 9/1964 1/-1967 STATES PATENTS Quast 72-249 Talbot 72-249 Properzi 72-249 Hornbostel 72-249 Hunter 72-234 Kocks et al. 72-249 l0 MILTON S. MEHR7 Primary Examiner UNITED STATES PATENT OFFICE CERTIFICATE 0F CRRECTION Patent No. 3 546 9l5 Dated December 15L 1970 Inventods) Jose Severin et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as show-n below:

Column 2 line 28 after "end" insert of the mill Column 4 line 35, after "ll" insert a comma.

Signed and sealed this 27th day of April 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, J] Attesting Officer Commissioner of Patent:

I FORM PO-1050 (1D-59) USCOMNMDC 60376 Uil. GOVIINHIIIT PRINTING OFFICE t Illl O-Sl

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