US2642763A - Cross rolling mill - Google Patents

Description

June 23, 1953 F. B. ABRAMSEN 2,642,763

CROSS ROLLING MILL Filed March 26, 1947 s Sheets-Sheet 2 INVENTOR FINN B. ABRAMSEN j/fl/fino' MK-M June 23, 1953 I F. B. ABRAMSEN 2,642,763.

CROSS ROLLING MILL Filed March 26, 1947 5 Sheets-Sheet 3 INVENTOR FINN B. ABRAMSEN 4 1 afl- 7 Q 5% WWW Patented June 23, 1953 CROSS ROLLING MILL Finn B. Abramsen, Baldwin Township, Allegheny County, Pa.

Application March 26, 1947, Serial No. 737,210

1 This invention relates to a cross-rolling mill for reducing the diameter of and for sizing round bar stock. It may also be used for straightening rounds. The rolling of round bar stock by crossrolling is well known. However, the art has long sought means not only to increase the production of cross-rolling mills but also to produce a cold rolled bar which is equal to or superior than a cold drawn bar in accuracy of size and smoothness of finish.

It is obvious that the production rate of a mill can be increased by increasing the amount of reduction accomplished in each pass through a stand of rolls and also by increasing the linear speed at which the mill operates. It is also well known that large reductions per pass improve the physical characteristics of the bar by deeper working of the metal. Increasing the reduction per pass and increasing the speed, however, create several problems which have not heretofore been solved.

Large reductions require extremely high roll pressures which, in turn, require large diameter rolls both to withstand the pressures developed and the driving torque necessary to force the work through the rolls. Large diameter rolls increase work hardening and do not provide sufficient room for anti-friction bearings. High rolling pressure also creates excessive wear on bearings of the type which can be used in the space 2 Claims. (Cl. 80-22) cut practice in cross-rolling rounds is to employ reductions per pass not exceeding approximately 1%. the above problems by creating additional heat in the bearings.

I have invented a cross-rolling mill which permits large reductions and high operating speeds. I employ small work rolls thereby decreasing work hardening and the total roll force but exert on them pressures sufficient to accomplish large reductions per pass for example, in the order of High rolling speeds serve only to increase 10%. The rolls are so small that they are not I self-supporting under the pressures required to obtain the reductions just stated.- Therefore, I support each work roll with a backing roll having necks, or an arbor, of such diameter that it can withstand the rollin pressures encountered. The

backing roll itself has a diameter considerably 2 larger than the diameter of its necks or arbor so that the roll may be supported in an anti-friction mounting.

The upper work rolls of a cross-rolling mill must be adjustable in two directions; vertically,

to apply different rolling pressures to the Work and to receive work pieces of varying sizes, and by rotation about a vertical axis to vary the angle which the axis of each work roll makes with the axis of the work. Both the vertical and'rotational adjustments are made before a workpiece is inserted into the roll pass and frequently they are made while a piece is being rolled."In the mill which I have designed, it is essential that each work roll and its supporting backing roll be kept in correct alignment with each other so that the rolling forces are transmitted in a plane passing through the axis of rotation of each roll. My invention therefore also includes a structure whereby each work roll is kept in alignment with its respective backing roll at all times and regardless of the adjustments that are made to the rolls.

In the accompanying drawings I have illustrated a present preferred embodiment of my invention in which,

Figure 1 is a side elevation of my cross-rolling mill with portions broken away to illustrate interior parts;

Figure 2 is a schematic diagram showing the arrangement of the workpiece, two work rolls and their accompanying backing rolls;

Figure 3 is a section along the lines III-III of Figure l;

Figure 4 is a section along the lines IVIV of Figure 1;

Figure 5 is a section along the lines V-Vof Figure 3; and

Figure 6 is a perspective view of a chock used in mounting the backing roll.

As shown in Figure 1 a cross-rolling mill constructed in accordance with my invention cornprises a lower housing I and an upper housing 8. The lower-housing is secured to a suitable foundation. Four posts 9 support the upper housing. Those portions of the posts which are within the upper and lower housings arereduced'in diam- 'eter so as to form shoulders III which support the posts on the lower housing 1 and shoulders II which support the upper housing 8 on the posts. Nuts 12 are secured at each end of each post against an outside surface of each housing to hold the housings in their relative position against the pressures developed during rolling. The lower housing 1 also supports a workpiece entering uide 13.

Figure 1 shows two stands of rolls. Figure 2 shows schematically one of the stands with a workpiece [4 in rolling position. A stand comprises two relatively small work rolls 15 of such diameter that they are not self-supporting under the roll pressures encountered. The body of each roll has a concave work-engaging surface cut therein so that when the rolls are crossed as shown in Figure 2 a cylindrically-shaped roll pass is formed, viewing the pass along the line on which the workpiece travels. Each roll has roll necks ll, one of which is slotted so that a conventional mill drive can be connected to each roll.

As above noted the work rolls are too small in diameter to be self-supporting. Therefore, I support each work roll with a backing roll l8, mounted on an arbor [9. The diameter of this arbor must be sufiicient to withstand the rolling pressures encountered and therefore is considerably larger than the diameter of the work rolls. The backing roll shown in Figure 2 is in the form of a ring which rotates about the arbor on selfaligm'ng' roller bearings 20. Instead of the ring type of roll such as is shown in Figure 2 a backing roll may be made of conventional design with a neck at each end of its body and roller hearings or other anti-friction bearings may be mounted on the necks. Whichever type of roll is used the diameter of the roll body should be sufiiciently great to provide space for an arbor or roll necks of sufficient size to withstand the roll pressures encountered and also to provide space for an anti-friction mounting such as roller bearings for the roll.

Figure 3 shows the relative positions of a stand of rolls [5 with respect to the housings and the relative positions of two stands of rolls and their driving connections. Thus the lower work roll of the left-hand stand of rolls (viewing Figures 1 and3') is drivenby a power shaft 2| through a universal joint 22. A power shaft 23 drives the upper'work roll of the right-hand stand of rolls 'a'nd'a shaft 24 drives the lower work roll of therigiht-hand stand of rolls.

"Figures '4, 5 and 6 show the manner in which a work roll and its supporting backing roll are mountedso thatth'work roll and its backing roll maybe adjusted both vertically and rotationally as a unit thereby keeping the two rolls in proper'alignment with each other. A frame 25 ofgenerally cylindrical shape is mounted in a space of similar. contour in each housing. Avertieei'openm'g'zs generally cross-shaped in section extends, through the frame 25 and contains the backing roll. Blocks 21 (Figure 6) are fitted over each end of the arbor l9 and have tongues 28 on each side which fit into vertically extending grooves. cut in the sides of the opening 26. It should also be noted that, as shown in Figures {and 5, circular guide plates 30 are placed on the arbor between the backing roll and the blocks 21. These plateshold the backing roll in proper position "on the self-aligning bearings. 20. A screwdown 3!. of conventional design exerts a downward force against a pressure plate 32 which extendsacross both blocks 21 to exert a rolling pressure onthebacking rolls which is transmittedby that roll to the work roll and thence to the workpiece.

As shown in Figure 5, portions of the frame 25 are extended downwardly below the blocks 21 to form bearing boxes 33 which carry bearings for the work 'roll 15. The bearings 34 on the neck of the work. roll which is not connected to the mill drive are of the ball thrust type. The bear- 4 ings 35 which support the neck of the work roll adjacent to the mill drive are preferably needle bearings. The bearing boxes on both ends of the work roll are closed by caps 36 and 31.

Figure 4 shows the means whereby the angle which a work roll makes with the workpiece may be adjusted. A rack 38 extends through a hole 39 drilled horizontally in a housing. One end of the rack has teeth 43 cut therein which mesh with teeth 4| cut in the periphery of the frame 25. The outer end of the rack 38 is reduced in diameter and threaded as shown at 42 in Figure 4. A hand wheel 43 has a hub 44 which is threaded to fit the threads 42 and has a groove 45. A split retaining plate 46 secured to the housing has shoulders 4'! which fit in the groove 45 and thereby hold the wheel against the housing. Rotation of the hand wheel in a clockwise direction withdraws the rack 38 through the hole 39 and thereby rotates the frame 25 and the rolls in a counterclockwise direction (viewing Figure 4) The effect of this rotation is to draw the work roll against the workpiece. Should it be desired to open the roll pass, the wheel is turned in the opposite direction.

The area of contact between the workpiece and the small work rolls which I have provided in my cross-rolling mill is relatively small. It results, therefore, that the total rolling forces are materially reduced. This decreases work hardening and avoids the necessity of a heavy housing or a large amount of power to drive the mill. The work rolls are too small to be self-supporting particularly at the one neck, which is reduced in diameter to permit the use of ball thrust bearings. However, the rolls are supported by backing rolls having a diameter in the order of the magnitude of six or seven times the diameter of the work rolls. The large diameter of the backing rolls thus permits an arbor or a roll neck of sufficient size to withstand the rolling pressures encountered. At the same time sufficient room is provided for a suitable anti-friction mounting for the backing roll. The anti-friction mounting of both the work and backing rolls not only reduces the amount of power required to drive the mill but also reduces to almost a negligible extent the heating of the roll bearings. The rolls are not therefore unduly heated and the contour of the roll pass is not deformed. It will be appreciated, therefore, that my invention greatly increases the production of a crossrolling mill first by enabling greater reductions per pass and second by permitting increased rolling speeds.

Not only have I increased the production of a cross-rolling mill by my invention but I have improved the product. Since the roll pass contour is not affected by bending of the rolls under heavy rolling pressures or by the flow of heat from the roll bearings into the roll bodies, the bars are rolled on my mill more accurately to gauge than has been possible on mills heretofore used. Also the heavy reductions with small rolls improve the physical properties of the bar and give it a much smoother finish than has heretofore been possible.

While I have described a present preferred embodiment of my invention it is to be distinctly understood that it may be otherwise embodied within the scope of the following claims:

I claim:

1. A cross-rolling mill comprising. a pair of crossed work rolls having their axes of rotation at an angle to the axis of the workpiece, a backing roll for each work roll, means for rotatably supporting each work roll and its supporting backing roll as a unit whereby said rolls are at all times in correct alignment with each other, means for moving the work rolls towards and away from each other to exert a rolling force on the workpiece, and means for turning said roll supporting means about an axis passing through the workpiece and at right angles thereto thereby varying the angle which the work rolls make with the workpiece and maintaining the backing rolls in alignment with the work rolls.

2. A cross-rolling mill comprising a mill housing, a pair of work rolls, a backing roll for each work roll, a frame for each work roll, said frame carrying the work roll and its corresponding backing roll as a unit so that said rolls are in correct alignment with each other, bearings in each frame for rotatably supporting the backing roll carried by the frame, bearings carried by each frame for rotatably supporting the work roll carried by said frame, a support in the housing for each of said frames, means for moving the frame so as to move the work rolls toward each other and means for rotating the frames about 6 an axis passing through the path of the workpiece through the mill and at right angles thereto whereby the angle between the longitudinal axes of the work rolls and the workpiece can be varied.

FINN B. ABRAMSEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 165,927 Helm July 27, 1875 331,582 Tasker Dec. 1, 1885 334,548 Tasker Jan. 19, 1886 1,119,044 Sargent et a1 Dec. 1, 1914 1,622,744 Y Stiefel Mar. 29, 1927 1,895,607 Coe Jan. 31, 1933 1,900,032 Worthington Mar. 7, 1933 1,979,133 Abramsen Oct. 30, 1934 2,314,953 Siegerist Mar. 30, 1943 FOREIGN PATENTS Number Country Date 152,080 Great Britain Oct; 4, 1920 617,216 Germany Oct. 9, 1931 7,732 Norway Nov. 24, 1898

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