US2911864A - Rolling mill - Google Patents

Description

Nov. 10, 19594 E. A. NELSON 2,911,864

ROLLING MILL Filed June 5, 1956 2 Sheets-Sheet 1 Nov. 10, 1959 E. A. NELSON 2,911,864

ROLLING MILL Filed June 5, 195e 2 sheets-sheet 2 7 a2 [nreryr Emil Nelson,

nited States Patent O M ROLLING MILL Emil A. Nelson, Oklawaha, Fla.

Application June 5, 1956, Serial No. 589,510

Claims. (Cl. 80-16) This invention relates to mills capable of cold rolling steel plates and particularly to mills for work plates or pieces in the form of steel discs operative to taper the disc in thickness toward the edges of the disc.

Mills in accord with this invention find particular utility in the forming of steel wheel discs for automobiles and other vehicles.

In the forming of steel discs for wheels, it is desirable that the discs be of maximum thickness throughout a center portion and that the thickness decrease gradually toward the rim or edge of the disc, and various mills have been developed in the past for accomplishing such tapering of wheel discs. This invention relates to an improved mill for accomplishing the above operation.

In the tapering of steel plate by cold rolling, high roll pressures are required, of the order of 100,000 pounds per roll, for example, while precision is'also necessary. The conflicting requirements of heavy pressures, rolling and moving parts, precise control and rapid operation make for large size, complexity and high cost of suitable machines.

It is a general object of this invention to provide a mill for cold rolling steel plate of improved simplicity of construction and capable of greater precision of operation, and operative to complete the tapering of the plate more rapidly than prior art machines.

It is desirable in disc tapering Imills that the untapcred disc work piece be quickly and easily loadable in or on the mill and as readily removable therefrom following the tapering operation, and mills wherein the disc is placed on a tapered table and subjected thereon to rolling by an overhead pressure roll have been heretofore suggested which have the advantage of relatively rapid loading, although unloading thereof tends to be difficult. It has also been known to bring two similar rolls into contact with opposite faces of a disc, the disc being held, usually in vertical position, by a rotatable center clamp', the two rolls squeezing the discl therebetween. In mills of the latter type, loading and unloading are slow and the application of suiiicient pressure to the rolls is diiiicult, requiring very heavy construction.

In accord with this invention the work piece is supported in horizontal position on a simple spincHe and is tapered by the action of relatively narrow rolls engaging the under surface of the work, and movable radially thereof, working against broad overhead idler rolls so positioned that the work-contacting idler roll surfaces are inclined at substantially the desired angle of taper.

The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

Fig."1 is a partially sectional front elevation of a mill in accord with this invention; f

Patented Nov. 10, 1959 Fig. 2 is a partially sectional end View of the mill, taken along line 2-2 of Fig. 1;

lFig. 3 is a fragmentary front elevational view of the mill illustrating the operation thereof;

Fig. 4 is an exploded view showing details of a portion of the adjustable thickness regulating mechanism of the mill;

Fig. 5 is a perspective view of a finished tapered disc work piece, shown partially broken away; and

Fig. 6 is a schematic diagram of a control mechanism for controlling the operating cycle of the mill.

As seen in Fig. 1, the mill 1 comprises a base l2 having smooth horizontal tracks -3 and 4 extending radially outwardly from opposite sides of the base 5 of a vertical fixed spindle y6. The spindle comprises an upper flanged portion 7 adapted to receive and rotatably to support in horizontal position an untapered steel plate work piece 8,

the work piece being preferably centrally apertured and preferably of ilat disc shape.

Two identical driven roll units 9 and 10 are provided to roll horizontally along respective tracks 3 and 4. Driven roll unit 9, to which unit 10 is identical, cornprises a carriage 1,1 supported on heavy wheels 12 which roll on track 3. A heavy roller bearing block 13, having bearing rollers I14 therein, and a roller drive motor 15 are rigidly attached to the upper surface of carriage 11, and motor 15 is coupled, through coupling 16, to drive a roller shaft 17 supported in 'bearing block 13 by bearing rollers 214. Shaft 17 carries a narrow forming roller `18 in position to engage the under surface 19 of the work piece I8 adjacent spindle 6 and, as unit 9 is moved outwardly along its track, the roller 18 moves outwardly across the surface of the work in a horizontal direction axially of the shaft .17 and roller 18. Inward and outward movement of unit 9 is obtained by means of a hydraulic liquid or compressed air ram or motor 20 fixed to base 2 'by bolts, such as bolt 21, and connected, as by drive rod 22, to the carriage 11. Pressure fluid is supplied through tubes 23 and 24 alternatively to operate ram 20 in the desired direction.

Ram 25 and rod 26 are arranged to roll lunit 10 toward and away from spindle 6, thereby to move `driven roller 27 in the direction of its axis across the under surface 19 of the work piece in the manner described in connection with ram 20, unit 9 and roller 18.

Base 2 desirably comprises a pair of side wall portions 28, '29 serving as track guides and shields for the' rollers of the carriages 11. Four upstanding guide and overhead frame supporting posts, such as posts 30, 31

and 32, are rigidly aflixed to and extend vertically up-` wardly from base 2. The posts rigidly support an overhead frame or assembly 33 above the work-supporting portion 7 of the spindle, being attached to the frame by suitable nuts, such as nut 35, which are threaded on the posts.

The four posts are approximately equally spaced about the axis of spindle 6,-and about the work piece 8,

and serve as vertical guides for an idler roll carrier member 36. A shaft 37 extends horizontally through ing rollers, such as roller 40. Idler roll 38 is seenl to be disposed in opening 41 in the carrier in which the roll fits suiiiciently closely to prevent appreciable end play of the roll. End play may also'be minimized by utilizing a bearing designed in a known manner to have little end play and to take end thrust.

The lower surface portion of roll 38 which contacts the upper surface 42 of work piece 8 is upwardly and inwardly inclined toward the axis ofV spindle `6 at substantially 'the desired taper angle of the finished disc.'

Thus the lower surface portion of the roll may be at an angle to the horizontal of from a fraction of 1 to as much as about 3 or 4. In the preferred embodiment illustrated herein, the upward inclination of the lower idler roll surface is obtained by utilizing frusto-conical idler rolls rotatable about the horizontal axis of journal shaft 37. It will be apparent that the roll surface may depart slightly from a true conical surface if desired to provide a varying final taper of the work piece. It will also be apparent that the inclination of the lower roll surface is dependent on the orientation of the axis of the roll, with respect to the horizontal.

Roll 39 is preferably identical to roll 38 and is identically arranged on journal shaft 37. Roll 39 contacts work piece 8 directly opposite the portion contacted by roll 38 since the rolls are preferably coaxially disposed on an axis intersecting the vertical axis of spindle 6. The axis of roll 39 and the axis of roll 38, in the arrangement shown in the drawings, are in a vertical plane including and defined by the vertical axis of spindle 6 and the horizontal aligned axes of the driven rolls 18 and 27. However, slight departures from such alignment may be desired in certain applications of the mill.

Carrier 36 is mounted to a piston rod 43 by means of rod flange 44 and bolts, such as bolt 45. Rod 43 extends upwardly from the carrier and carries a piston 46 disposed in a hydraulic fluid or air cylinder 47. Cylinder 47 is preferably formed as a part of frame 33 and has a lower packing arrangement 48 for sealing rod 43. Rod 43 comprises a preferably reduced diameter externally threaded upper portion 49 which extends, through packing or seal arrangement 50, upwardly through the upper wall or top 51 of the cylinder.

It will be apparent that forced downward movement of carrier 36 may be accomplished by introduction of pressure fiuid through upper tube 52 into cylinder 47, while the carrier may be raised by introduction of fluid through lower tube 53. The limit of downward movement of carrier 36 is established by an adjustable preset split nut 54 threaded on the upper end portion 49 of the piston rod, and by adjustable annular cam collar members 55 and 56. 'Ihe lower collar member 55 rests on the upper end wall 51 of the cylinder and upper collar 56 has a lower circular cam face 57 adjustably engaging and in register with upper circular cam face 58 of collar 55. Upper collar 56 has a projecting tab 59 so disposed in a vertical slot 60 of an outer annular frame portion 61 as to be attached or keyed to the frame in a manner to prevent rotation of the collar, while arm 62 extending laterally outwardly from collar 55 through horizontal slot 63 permits limited rotation thereof by means of a hydraulic expansible chamber adjusting mechanism indicated generally at 64.

Rotation of collar 55 by means of mechanism 64 through interaction of cam faces 57, 58 raises or lowers the upper face 65 of collar 56 in accord with direction of rotating of collar 55, and nut 54, which extends outwardly or laterally from the rod, in meeting face 65, functions as a stop to limit the downward travel of rod 43'and, accordingly, of carrier 36. Coarse adjustment of the limit of downward travel of carrier 36 is accomplished by rotaating nut 54 on rod portion 49 in a direction to raise or lower the nut thereon as desired.

Handle 66 of nut 54 provides a convenient means for rotating the nut, and, as shown in Fig. 2, the nut 54 is preferably split and provided with a clamping bolt 67 by which it is locked against inadvertent turning on rod portion 49.

lFig. 2 further discloses details of the mechanism 64 for making fine adjustments of the lower travel limit of carrier 36. The adjusting mechanism is mounted on an extension 68 of the upper frame assembly 33 and comprises a double acting hydraulic uid or air ram or motor 69 having two pressure fluid'inlets 70 and 71 and a piston rod 72 connected to arm 62 of cam collar 55. The ram is anchored to frame extension 68 by means of a small post 68a. Rod 72 is threaded to carry suitable lock nuts 73 as stops cooperating with suitable bosses, such as boss 74, to limit the permitted travel of rod 72 or, if desired, to lock rod 72 in a predetermined adjusted position.

The several elements and assemblies of the mill are similarly identified throughout the figures of the drawings to assist in comparisons between the several views, and the description of each figure will be understood to be equally applicable to the similarly identified portions of the mill in other figures.

By comparing Figs. l and 2 it will be noticed that idler rolls 38 and 39 are disposed for rotation about respective axes which lie in the respective vertical plane passing through the axis of the respective underlying driven roll 18 and 27. Thus roll 39 contacts the work piece directly above roll 27. Since shaft 37, in the disclosed embodiment, provides a journal for both of rolls 38 and 39, these idler rolls are coaxially arranged, as are driven rolls 18 and 27, and it will be apparent that all of the rolls rotate about axes which lie in a single vertical plane, and that this plane further includes the coincident axis of rotation of the work piece and axis of spindle 6.

Tracks 3 and 4 are horizontal and bounded by upstanding edge portions 28, 29 and the units 9 and 10 are movable in the horizontal directions of the common driven roll axis.

Fig. 3 shows the mill in operation to taper work piece 8. Carrier 36 is in lowered position, with nut 54 engaged with cam roller 56 and with idler rolls 38 and 39 in contact with the upper face 42 of the work. Pressure of rolls 38 and 39 on the Work may be determined in accord with the differential pressure between tubes 52 and 53 and thus, if the degree of taper and hardness of the work piece material are such as to make impractical the complete tapering function in one outward pass of rollers 18 and 27, the rollers 38 and 39 may be forced upwardly from the lower limit position as rollers 38 and 39 progress outwardly.

It is preferred, when more than one pass is necessary, to remove some or all of the downward pressure of rolls 38, 39 on the work piece, by appropriately adjusting the cylinder pressures through tubes 52 and 53 during the inward travel of the driven rolls and again to increase the pressure during the working travel of the drive rolls in the direction of arrows 75 and 76 respectively.

It is also possible to adjust cam collar 55 in progressive steps to progressively lower the limit position of the idler rolls for each working pass of the driven rollers until on -a final pass the work piece has the appropriate desired taper.

The operating surfaces of driven rolls 18 and 27 are sufficiently narrow to contact only a limited radial portion of the work and, for example, may be one-half or less of the width of the idler rolls. The driven rolls are slightly bevelle'd or rounded along the outer edges as at '77 to reduce marking or grooving of the undcrsurface of the work.

Cam collars 55 and 56 are shown in detail in Fig. 4, and it will be seen that cam surface 57 of collar 56 is .arranged to fit against cam surface 58 of collar 55, with each inclined surface portion, such as portion 78, of surface 57 adapted to lie against `a corresponding inclined surface portion, such portion 79, of surface 58.

A finished tapered disc work piece 8 is shown in Fig. 5, having an upper surface portion 42 inclined to the horizontal flat under surface 19 at substantially the same angle as the angle of inclination of the lower working surface of the idler rolls of the mill. The finished work piece will have an overall diameter somewhat greater than the original diameter of the original untapered work piece. Central aperture of the finished work piece would be originally formed in the blank to permit support of the work piece on the mill spindle.

A suitable control arrangement for the mill is shown in Fig. 6 and operation of the mill through a typical cycle is controlled by this arrangement in response to momentary closure of starting switch 81 to apply energizing current to coil 82 of control relay 83 from electric power bus 84. Timing motor 85 is started in response to actuation of relay 83 and the motor initiates rotation of switch cams 86, 87, 88 and 89. Cam 86 closes its switch 90 establishing a holding circuit in shunt with starting switch 81 to maintain relay 83 in energized condition through the cycle. Substantially simultaneously switch 91 is closed by cam 89 causing energization of the coil 92 of an idler roll pressure control valve 93. Valve 93 operates in response to energization of coil 92 to admit pressure fluid from a pump 94 into tube 52, thereby to force carrier 36 downwardly, and simultaneously to relieve pressure in tube 53 through exhaust or return line 95. A pressure relief valve 96 may be connected to pump 94 to limit the maximum applicable to the controlling rams and cylinders of the mill and its control system.

Shortly after carrier 36 is lowered as a result of the actuation of valve 93, cam 88 closes its switch 97 energizing solenoid valves 98 and 99 to admit pressure iluid from pump 94 into line 23 of ram 20 and line 100 of ram 2S to provide outward movement of the driven roll carriages. Adjustable regulating valves 101 and 102 are arranged in the branch lines 103 and 104 connecting pump 94 with the respective carriage control Valves 98 and 99 to permit speed control and balancing of oper-ation of the carriage transporting rams.

The first outward traverse of the driven rolls may be accomplished with the cam collars in a first position co1'- responding to the position shown in Fig. 2, for example. The upper collar surface, in this position, stops the nut 54 with the idler rolls at what may be termed -a first pass Working level, while movement of arm 62 to the right as seen in Fig. 2 will lower the limit position of the idler rolls, whereby they may assume a second pass working level which is, for example, la small fraction of an inch lower than the rst pass Working level.

Referring again to Fig. 6, it will be seen that cams 88 and 89 open switches 97 and 91 after a predetermined period of operation, which should be timed to permit the driven roll carriages to have reached the desired outer limit position. Each of valves 98 and 99 may be identical to valve 93 and provided with a return spring such as spring 105 of valve 93, and, as energizing current for the valves 93, 98 and- 99 is interrupted by the opening of switches 91 and 97, the valves return to rest position, permitting pressure iluid to enter line 53, to raise the idler roll carrier, and lines 24 and 106 of rams 20 and 25, respectively, thereby to cause transporting of the driven roll carriers to their inward limit positions. Simultaneously, fluid may exhaust, if air, or return, if a liquid, through lines 52 and 107 of the carrier pressure cylinder and valve 93, through lines 23 and 108 of the ram 20 and valve 98, and through lines 100 and 109 of ram 25 and valve 99.

As carrier 36 starts to rise in response to opening of switch 91, cam 87 closes its switch 118 to energize the solenoid 111 of a spring return valve 112, thereby acting to supply pressure fluid through pressure pump line 113 and adjustably preset reduction valve 114 to line 70 of ram 69, and, simultaneously, to relieve pressure in line 71 to exhaust or return line 115. Motion of rod 72 which results from actuation of valve 112 steps the lower cam collar into position to establish the second pass working level limit for the idler rolls.

Following completion of the movement of rod 72, cam 89 again closes switch 91 to energize coil 92 and actuate the valve against the bias of spring 105, reestablishing the pressure fluid connection to line 52 and the pressure relief connection from line 53 to line 95. Thereafter, the carrier 36 having reached its second pass limit posi'- tion, cam 88 again closes switch 97 to actuate valves 98 and 99, permitting escape of uid from line 106 to return or exhaust line 116 and from line 24 to return or exhaust line 117, and application of pressure fluid to lines 23 and 100.

Toward the end of the cycle, after the second working traverse of the driven roll carriages, switches 91, 97 and 110 are all opened by their respective associated cams, thereby causing spring return of each of valves 93, 98, 99 and 112 into positions to raise idler roll carrier 36, to move the driven roll carriages inwardly toward the Work supporting spindle and to rotate the lower cam collar into position to reestablish the first pass limit position for the idler roll carrier. Cam 86 finally returns with the other switch cams to the positions shown in Fig. 6, switch 90 opens and relay 83 drops out. The tapered work piece may now be replaced by a new work piece on which the mill is to operate through the next cycle.

It is assumed in the above described sequences of an exemplary operating cycle that pump 94 shown in Fig. 6 is constantly operating, and that the motors for driving rolls 18 and 27, such :as motor 15, are also constantly operating.

Various modifications of the control arrangement will occur to persons skilled in the art to accord with the number of passes of the driven rolls across each disc, the extent of taper desired and other factors.

It will be seen that the mill of this invention comprises driven rolls movable on their carriages directly backwardly and forwardly, or outwardly and inwardly, from and toward the spindle, and further comprises a pair of idler rolls each rotatable on an axis fixed with respect to a carrier and the carrier need be moved only vertically upwardly and downwardly. The mill, accordingly, requires only simple motions of the main movable parts, the parts are of relatively simple design and may be easily constructed with sufficient sturdiness to withstand the high forming pressures required for rapid forming of the work piece. It will also be apparent that the machine is readily adjustable, for example, to compensate for wear of the rolls, i.e. by adjusting nut 54 or by adjusting the positions of nuts 73 on rod 72, and parts subject to wear are k readily replaceable when necessary with a minimum of mill disassembly.

While only certain preferred embodiments of this invention have been shown and described by way of illustration, many modifications will occur to those skilled in the art and it is, therefore, desired that it be understood that it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of this invention.

What is claimed as new and what it is desired to secure by Letters Patent of the United States is:

1. A mill for cold rolling steel plates comprising a base, a spindle fixed in position relative to said base, a plurality of vertical members fixed to and extending upward from said base and spaced about said spindle, an overhead frame assembly supportedly affixed to said vertical members and disposed above said spindle, said base having a pair of tracks extending horizontally outwardly on opposite sides of said spindle, a pair of units, rollers supporting one of said units on one said track and thek other said unit on the other said track, each said unit comprising electric motor power means, a roll driven by said power means, and means supporting said roll at a xed distance above said rollers, force means for moving said units along said tracks toward and away from said spindle, said spindle comprising means to -support a work plate generally in a horizontal plane with its lower surface engaging the upper surface of said rolls, a pair of idler rolls disposed above said horizontal plane and adapted and arranged to bear against the upper surface of said work plate, an idler roll carrier member, axle means engaged in said carrier member supporting said idler rolls on said carrier member for free axial rotation, each said idler roll having a lower work-contacting surface, said axle means being oriented to dispose the rotational axis of each said idler roll substantially vertically above the axis of rotation of a respective one of said driven rolls and to dispose the lower work-contacting surface of each said idler roll in an inwardly and less than 4 upwardly inclined position, said `frame comprising a vertical operating cylinder, said cylinder having a piston connected to said carrier member and operative to force said carrier member vertically downwardly, said carrier being in guided engagement with said vertical members.

2. in a rolling mill having rolls of lixed height for rolling against one face of the work, the combination of a movable carrier having rolls rotatably carried thereon for rolling against the opposite face of the work, a piston rod connected to said carrier, a piston on said rod, means to apply hydraulic pressure to said piston in a direction to force said carrier toward the work, a stop element affixed to said rod and extending laterally outwardly therefrom, a fixed frame having a portion spaced in said direction from said stop element and disposed adjacent said rod, a pair of annular cam collars surrounding said rod disposed between said frame portion and said stop element, each said collar having a respective circular cam face and said faces being in registering contact with each other, and means connected with said collars for adjusting the rotational position of one with respect to the other said collar.

3. The combination of claim 2 wherein the means connected with the collars for adjusting the rotational position of one with respect to the other said collar comprises an expansible chamber device having a portion connected to the frame means and a second relatively movable portion connected to said one collar and further comprises means interconnecting said frame means and said other collar, selectively operable means for supplying pressure fluid to said expansible chamber device, and stop means engageable by said second portion of said expansible chamber device.

4. A metal disc tapering mill comprising a base, an upstanding spindle carried by said base, at least two vertical members fixed to and extending upwardly from said base and disposed outwardly of and on opposite sides of said spindle, an overhead frame assembly supportedly affixed to said vertical members spacedly above said base and including an upright cylinder, said base including a first xed track extending generally horizontally outwardly from said spindle in one direction therefrom and a second fixed track extending generally horizontally outwardly from said spindle in the opposite direction, a rst carriage unit having supporting rollers engaged on said first track and a second carriage unit having supporting rollers engaged on said second track, each said carriage unit comprising a respective work-engageable narrow faced roll, respective means rotatably mounting said roll thereon at a fixed distance above the suppoiting rollers and respective motor means carried thereon for driving the respective roll thereof, force means for moving each said carriage unit along its respective track toward and away from said spindle, said spindle comprising means for supporting a work piece disc above said rolls to be contacted on its lower face by said rolls, a carrier member, means disposed above said spindle mounting said carrier member on said overhead frame assembly, said mounting means comprising a piston disposed in said cylinder and means fixing said carrier member to said piston and disposing said carrier below said cylinder and above said spindle-supported work piece disc, two idler rollers rotatably mounted on and having work surfaces wider than the work faces of said rolls protruding below said carrier member and adapted and arranged t0 engage the upper face of the work piece disc, each said roller being generally aligned above a respective one of said rolls, amd means for introducing pressure fluid into said cylinder above said piston to force said carrier member downwardly thereby forcedly to engage said carrier member rollers against the upper face of the work piece disc.

5. In a steel plate disc tapering mill, a pair of narrow driven rolls of equal diameters, driving means supporting said rolls for driven rotation about respective predetermined horizontal, generally aligned axes, said means comprising means for moving each said roll axially inwardly and outwardly toward and away from the other between respective predetermined limits of travel, a pair of idler rolls, each said idler roll having an elongated surface between said limits of travel, of a respective corresponding one of said driven rolls, each said idler roll being freely rotatable on an axis vertically displaced above the axis of the respective driven roll, each said idler roll having a lower surface portion facing the respective driven roll and the axis of each idler roll being oriented to dispose said lower surface portion thereof at an angle of less than about 4 degrees to the horizontal and extending downwardly at such angle in a respective outward direction, a carrier member, said idler rolls being rotatably mounted on said carrier member for rotation about their respective said axes, a hydraulic cylinder having a substantially vertical axis, a piston vertically movable in said cylinder, a piston rod connecting said carrier to said piston, said cylinder having a top above said piston, said rod extending upwardly of said piston and through and above the top of said cylinder and having an externally threaded portion above said cylinder, a nut threaded on said threaded portion, two collars interposed between said nut and the top of said cylinder, each said collar having a respective circular cam surface and said cam surfaces being in registering engagement, and adjustable means connected to said collars operable to adjust the rotational position of one said cam surface with respect to the other.

References Cited in the le of this patent UNITED STATES PATENTS 1,350,057 Bell Aug. 17, 1920 1,588,146 Schlumpf June 8, 1926 1,698,373 Nelson Jan. 8, 1929 1,788,551 Smith Jan. 13, 1931 2,091,578 Batie Aug. 31, 1937 2,379,840 Stuhlman July 3, 1945 2,406,219 Hight et al. Aug. 20, 1946 2,647,423 Horn Aug. 4, 1953

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