US2101266A - Rolling mill - Google Patents

Description

Dc.7,1937. J, "2,101,266

ROLLING MILL Filed Jan. 12, 1935 3 Sheets-Sheet 1 INVENTOR J. J. MUNSON ROLLING MILL Dec. 7, 1937.

Filed Jan. 12, 1935 3 Sheets-Sheet 2 J. J. MUNSON Dec. 7, 1937.

Patented Dec. 7, 1937 UNITED STATES PATENT orrrca 11 Claim.

This invention relates more especially to that type of rolling mills in which so-called floating pressure rolls are employed in opposition to one or more fixed axis rolls for operating upon material of varying bulk passing through the mill. My present invention is illustrated on the accompanying drawings in its adaptation to a sugar cane mill. In mills of this character, a top pressure roll is usually suitably mounted for an upward and downward movement with respect to one or two other rolls which usually rotate about fixed axes, the bearings for said top pressure roll being constructed and arranged Ind to permit a relative tilting of the rolls axis of rotation with respect to the fixed axis or axes of the roll or rolls cooperating therewith.

The primary object of my invention is to provide an improved construction, combination and arrangement of parts in rolling mills of the character referred to for the purpose of overcoming certain inherent drawbacks related to the transmission of high pressures to the floating roll under non-uniform and irregularly applied stresses imposed upon slidably contacting parts of rolling mills commonly employed at the present time.

Another object of my invention is to provide a hydraulic system of improved construction whereby a variable pressure load may be applied to a floating bearing without the acceleration or deceleration of heavy masses which render the operation unsteady and uncertain.

Specific features of construction and arrangement will be pointed out in the specification, refr erence being had to the accompanying drawings which illustrate a preferred embodiment of my invention.

. In the drawings-- Figure 1 is a side elevation of one section of a sugar cane rolling mill with attached hydraulic system, parts being broken away, parts shown in section, and with the accumulator or pressure receiver detached and arranged below its true position for economizing space on the drawings. Figure 1a is a side elevation on a reduced scale of the right-hand portion of Figure 1, with the accumulator shown in its true position raised above the piston chamber.

Figure 1b is a diagrammatic side elevation of a modified form of the hydraulic pressure connections.

Figure 2 is an enlarged side elevation of the 5 left end of Figure 1 with the nearer roll-supi ing frame removed and the roll journals shown in section.

Figure 3 is an enlarged transverse section of one of the upper roll bearings and parts contiguous thereto.

Figure 4 is a vertical transverse section on an enlarged scale of a modified form of one of the bearing members for the floating roll, contiguous portions of the frame being shown in elevation.

Figure 5 is a detail transverse section on a somewhat reduced scale of another form of pressure-equalizing bearing member.

Figure 6 is a view similar to Figure 5 showing the movableparts in changed positions.

Figure 7 is a transverse section on a somewhat larger scale of a modified form of the bearin member shown in Figures 4 and 5, portions being broken away and parts being shown in elevation.

According to present day practice, roller mills of the conventional type are subject to serious drawbacks due in large measure to excessive friction in the bearings and by reason of binding between bearings andhousings as well as to the effects of inertia in heavy moving parts.

These untowardconditions are especially bad on that side of the mill adjacent to the intermeshing spur gears commonly termed crown wheels". I

It is usual with roll mills of this character to employ hydraulic accumulators and. due to the construction. of accumulators commonly employed for loading the floating or top rolls of these mills, the free movement of these floating rolls is greatly retarded by-the large mass of iron which is .usually supported by a rod of small cross-section by means of which said mass of iron must be raised hydraulically by the upward displacement 'of the pistons through which the roll bearings .are loaded. This relatively small rod which supports as much as 10,000 to 30,000 pounds of weight has a very small area ccmpared with the total area of both pistons used to load the top roll; therefore, a very small movement of the roll causes a very much larger movement of the small rod and accumulator weights, for the purpose not only of starting the mass from rest at times but also for rapidly accelerating the movements of the several masses which must respond to upward displacements of the top roll and hence oifer high resistance to the rolls accommodation to increasing thickness of the mat and also producing severe shocks when downward movements of the roll along with the falling accumulator weights are suddenly checked.

'Ihe friction between the top roll bearing and the housing frequently corresponds to a 200,000 pound horizontal pressure on the top roll journal. Where gears or crown wheels are used on both sides of the mill, that is to say, two .crown wheels to each roll, the force which causes friction in the top bearing is more evenly distributed but may readily correspond to 100,000 pounds horizontal pressure on each journal of the'roll in large mills. According to common practice'at the present day, the bearing boxes for the journals of mill rolls are parted along a horizontal plane through the axis of the mill roll and quite commonly an open space is left between the upper and lower bearing boxes. In view of the explanation given above, it will be seen that a force of 200,000 pounds, say, operating upon the roll journals in substantially a horizontal plane in the direction in which the mat passes between the rolls, produces a tremendous turning moment on the upper bearing block and by its tendency to revolve said bearing block in a clockwise direction, produces a powerful binding action between the bottom forward and rearward upper corners of the bearing block and the front and rear guide surfacesrespectively of the housing. For the purpose of overcoming these drawbacks,- the present invention contem- 1 plates an improved bearing box construction whereby the forwardly directed pressure on the roll journals may be more uniformly distributed and applied over a wider area of contact while at the same time localizing the pressure in such away as tocounteract in large measure the turning moment referred to above. As an alternative device for overcoming these drawbacks, my invention contemplates abearing box of improved construction according to which an upper portion of said bearing box or the bearing box entire may be relieved of all frictional engagement with the housings by a pivotal anchorage distant from and to the rear of the roll.

While the drawings illustrate my invention in an adaptation to a rolling mill having the same general characteristics as that shown in U. S.

Patent No. 1,978,218 which was granted to Carl S.,

unhampered movement of the top roll of a rolling mill Referring to Figures 1 and 2 of the drawings,

one of the rolling mill sections of a sugar cane.

crushing and rolling mill is shown for the purpose of illustrating my invention. According to these drawings, a main bed plate I serves to mount axially spaced side frames or standards of such a mill, only one of said side frames being shown at 2. Journalled within said side frames, are front and rear cane crushing rolls 3 and 4 with their axes 3a and la of rotation arranged substantially in a common horizontal plane. Said front and rear crushing rolls are journalled in suitable bearings to be presently described, which are maintained in suitable relative positions by means of bearing caps 5 and 6 which are bolted to the oppositely arranged side frames or standards. Mounted above and substantially cenblock 9,'said pressure block being provided with an upper cylindrical bearing surface iii to adapt said pressure block to adjust itself angularly over the concave lower perimetral surface of a chambered cap H which is jointed to the bottom end of a hydraulic plunger i2. During the rising and falling movements of the floating pressure roll l, the bearing members or blocks 8 are in slidable engagement with guide surfaces formed in the side frames 2 and, by reason of their construction and arrangement, operate to counterbalance the binding effects as hereinafter explained. Said plunger I2 is reciprocably mounted within a cylinder l3 and closed above by a plunger block it arranged below a mill housing cap i5 which is bolted to the side frame or pedestal, as shown in Figure 2 of the drawings. The hydraulic pressure chamber in cylinder l3 may be sealed-above and below by leather packing cups i6 and H within which circular plates [6a and Ila respectively are seated. Interposed between the circular plates i611. and Ila, is a compression spring to the present invention, however, I preferably employ a hydraulic system of improved construction for this purpose to be hereinafter described. Patentee. Nadler, in his above-identified patent,

has disclosed a rolling mill construction whereby any desired portion of the heavy pressures which are usually transmitted through contacting metal surfaces of the plunger and pressure block, may be transmitted by the direct application of hydraulic pressure to the pressure block. For this purpose, the plunger l2 may be provided with an opening or passage 19 extending therethrough to an auxiliary pressurefiuid chamber 20 formed between the lower end of the plunger l2 and the top wall of the pressure block 9. By means of this device, the contacting metal surfaces may be relieved of any desired portion of the friction.- creating stresses transmitted through the oscillatably contacting portions of the hydraulic plunger and pressure block. As shown in Figure 1 of the drawings, the main pressure fluid chamher 2| which communicates through the passage I9 with auxiliary pressure fluid chamber 20, is supplied with oil through a pipe 22. The pipe 22 leads from the bottom end of a hydraulic cylinde'r 23 through a T-fitting' 24, one branch of the pipe fitting 24 being connected up to a supply pipe 25 from a hydraulic pump (not shown). A hand valve 26 may be included in the supply pipe 25 for controlling the admission of oil to the hydraulic system from the pump. A hydraulic plunger 21 which operates vertically in the cylinder 23 is'surmounted by a piston 28 arranged above the upper end of cylinder 23. said piston being reciprocably mounted in a cylinder 29 of relatively larger diameter than the cylinder 23 .and forming a movable wall of anoil chamber 30 which is always filledwith oil. The oil cylinder 29 is supported by columns 3i from the bednlate 32 of the hydraulic cylinder 23. Leading from a cylinder head 33 on the up er end of cylinder 29, is a large pipe 36 which is connected to the lower end of a pressure receiver 35 which extends upwardly from a level above the upper end of the cylinder '29. as shown in Figure 1a of the drawings. In Figure 1, said pressure receiver 35 is shown in a depressed position to permit its representation on an enlarged scale. In the upper right-hand portion of Figure 1 of the drawings, is shown a compressor air receiver 36 connected by a pipe 31 to the upper end of receiver 35, a pressure reduction valve 38 being interposed between compressed air receiver 36 and pressure receiver 35 for a purpose. to be hereinafter explained. A safety valve 39 and a check valve 40 are preferably connected up in pipe 31, the former being constructed to limit the rise of pressure in said pipe and the latter being constructed to retain a predetermined pressure in the pressure accumulator cylinder 35. Leading from the upper end of the pressure accumulator 35 is a pipe 4| which is connected to a housing 42 for a diaphragm (not shown) by means of which the pressure reduction valve 30 is operated against the resistance offered by a compression spring 38*. Connected to the pressure accumulator 34 near the top is a T-pipe fitting 43 to one branch of which is connected a safety valve 44, a release valve 45 being connected to the other branch of said T-fitting. A pressure gage 46 may be connected to the pressure accumulator above the surface of the oil therein. For the purpose of explaining the utility of the parts described above, let it be assumed that the hydraulic plunger 21 is in its lowermost position within the cylinder 23. By opening a valve 41 which is arranged above the upper end of the oil cylinder 22, light oil is permitted to flow from any suitable source through a pipe 43 into the pipe 34 until the oil chamber 30, pipe 34, and pressure receiver 35 are filled up to a predetermined level K in said pressure receiver. Valve 41 is then closed, after which the valve"26'in the oil supply pipe 25 is opened to admit oil to the lower end of cylinder 23 for raising the hydraulic plunger 21 to a desirable operating level. By means of this movement, sufiicient oil is forced from the chamber 30 to raise the oil in pressure accumulator 35 to a new level such as M. After closing-the valve 26, compressed air from compressed air receiver 35 is permitted to flow past the pressure-reduction valve 38 and through the pipe 31 into the upper end of pressure accumulator 35 to any desired pressure under which the mill rolls are to be--operated, this pressure being transmitted through the oil chamber 30, piston 28, and hydraulic plunger 21 which transmits the same unit pressure through pipe 22 to the main pressure chamber 2| above each of the top-roll bearings.

As cane is supplied to the mill rolls, the top mill roll is displaced upwardly and thus produces a back pressure through pipe 22 anda corresponding displacement of oil from chamber 30 and a consequent rise of oil in pressure-accumu lator 35. Under these conditions, the check valve 40 prevents any displacement from 'the pressure accumulator 35 so that the pressure of the air is automatically raised by each upward movement of the roll journal and piston i2 corresponding thereto. Thus, with an increase in the amount of cane fed to the mill, the upward movement of the top roll produces an automatic increase of pressure applied to the cane at a rate-which may be governed by regulating-the. a-mountbf oil in the pressure accumulator 35; From the foregoing description of my improved form of .accumu- 76 lator, it willbe readily understood that various to be concentrated at a lower line R.

drawbacks inherent in old typeaccumulators will be overcome in the new form described above. Thus, in accumulators of the old type, a great mass of metal must be supported on and accelerated by a hydraulic plunger of relatively small cross-section with resultant shocks, unsteady operation and high frictional resistance, whereas an accumulator of the form contemplated by the present invention operates smoothly under pressure changes which respond automatically and with an unbroken continuity to changes in load imposed upon the mill. At the same time, the total load imposed upon any top roll hearing may be changed at will by the optional change of the predetermined pressure of the compressed air in the-upper end of the cylinder 35.

As stated above, in efiect. there may be as much as 200,000 pounds horizontal pressure on the floating top roll journal in the direction in which the sugar cane passes through the rolling mill. As usually constructed, the top bearing box extends less than half way around the journal and has its.

oppositeedges spaced from the horizontal axial plane of the journal. The central line of the contacting surface of this bearing block lies in' the vertical axial plane of the journal. The reaction pressure on the old form -of bearing'block, due to its contact with its guide, may be considered as concentrated along a line midway be.- tween its top and bottom side edges as indicated by the broken line arrow R in Figure 3, the bottom edge of said old form of bearing block being indicated at X: Under these. conditions, a journal pressure of 200,000 pounds in the horizontal axial plane of the journal would in conjunction with the reaction pressure R constitute a couple and produce a tremendous turning moment tending to revolve the bearing block in a clockwise direction. It is readily seen thatthe tendency for the hearing block to bind in its guides is tremendously increased by the turning moment referred to above. In consequence, a force of great intensity is required to make the bearing block slip in its guides.

The present invention contemplates simple and effective means .for overcoming the drawbacks alluded to above. and for this purpose an improved construction and arrangement oif the bearing member whereby the above described defects usually inherent in the bearings for floating mill rolls, may be eliminated. One form of my improved bearing is illustrated in Figure 3 of the drawings wherein it is shown in combination with block which formerly terminated at the broken line X, is provided with an integrally formed extension terminating below the 'horizontal axial plane at a line R. In consequence, the pressure reaction on the bearing block which formerly was considered to be concentrated at B, may in my improved form of bearing block, be considered This construction therefore greatly reduces the moment arm of the clockwise turning moment and at the same time produces a counterclockwise turning moment acting on the bearing block and consisting ofthe force F and an additional reaction pressure R the latter being directed to the lower lefthand corner or edge of the bearing block. In this way, the binding eifects between the bearing block and its guides may be reduced to such a degree 7 that by offsetting the vertical axis iii of the plunger i 2 (see Figure 3) the proper distance from the vertical axial plane of the journal, the bearing or bearing block 8 is readily brought into equilibrium with respect w. the turning moments referred to above in such a way as to uniformly distribute the pressure over the contacting surface of the bearing block 8 with the vertical guides within which it slides. In consequence, there will be a large reduction in friction as well as a reduction in the amount of pressure required for overcoming said friction during theuup and down movements of the top bearing block.

Referring now to Figure 4 of the drawings which shows another embodiment of this form of my invention, the bearing member may be constructed as a closed box bearing comprising a bottom bearing block 52 jointed to an upper bearing block 553 at 5% and completely housing the journal 55 of a floating mill roll, said bearing blocks being rigidly united by threaded bolts 5% and slidably mounted in the frame guides as indicated. A pressure block 5i maybe interposed between the bearing block and the lower end of a hydraulic plunger 58 of the Nadler type.

According to the embodiment of my invention shown in Figures 5 and 6 of the drawings, sliding friction as well as binding between bearings and guides may be entirely eliminated by constructing the bearing member to comprise an upper bearing block 59 of suitable form and size for un;

encumbered vertical movements and a rearwardly presented rocker arm to which carries a rocker at for oscillatably engaging a frame portion 53 in the form of, a'bracket mounted on the side frame 66. A suitable opening $5 in the side frame permits the rocker arm 66 to swing freely and provides for an untrammeled up and down movement of the bearing block 59, the raised position of saidbearing block 59 being shown in Figure 6'. Suitable means for preventing a down ward displacement of rocker ti in the absence of pressure thereon, may be provided in the form of a pin 62 which interengages pivotally with the rocker ti and frame portion t3 without interfer ing with a free oscillatory movement of one upon the other. It will be understood that this embodiment of my invention may be employed with or without the expedient of offsetting the center line of hydraulic plunger 02 with respect to the vertical axial plane of the journal in'the manner shown in Figures 3 and 4.

As shown in Figure 7 of the drawings, the journal 65 of the floating roll may be completely boxed in a bearing member comprising maring sections at and 88 jointed along planes G9 and it offset from the vertical, axial planeof journal 56 and secured together by bolts H which also secure a socket plate 12 thereto. Said socket plate may be provided with a rocker-arm it having a rocker it in oscillatable engagement with a flat bearing surface on the outerend of a bracket 85, which forms a portion of the side frame, a retaining pin Ma being arranged to pivotally interengage between rocker la and bracket le'for preventing a downward displacement of the former when no pressure is brought to bear thereon.

Referring nowto Figure l'b-of the drawings, my invention also contemplates a hydraulic press of the character shown inv Figure 1 with the pipe as leading from the oil compartment of the compressed air hydraulic accumulator'35 connected directly to the pipe 22 leading into the hydraulic pressure chamber of the hydraulic amassepress. In places where high air pressures are available, an assembly of this character provides an improved system in which the regulation of applied pressures is more directly and rapidly accomplished and wherein changes in pressure in one part of the system are instantaneously transmitted to other parts of said system.

I claim:

1. In a device of the character descri, the combination with a fixed frame provided with spaced vertical guide surfaces, of'a mill roll rotatable about a. tiltable axis, a bearing block rotatably engaging said mill roll and slidably engaging said spaced parallel guide surfaces, said mill roll being in journalling rotatable engagement with said bearing block and subject to a lateral journal pressure substantially normal to one of the guide surfaces, and means operating downwardly on said bearing block between said guide surfaces for counteracting the upward tilting movements of said ll roll, said bearing block being provided on the side exposed to said journal pressure with a downward extension in slidable engagement with said one of the guide surfaces above and below the axis of said mill roll.

2. In a device of the character described, the combination with a fixed frame provided with spaced vertical guide surfaces parallel to each other, of a mill roll rotatable about a tiltable axis, a bearing block slidably engaging said spaced parallel guide surfaces, said mill roll being in rotatable engagement with said bearing block and subjecting said block to upward and lateral stresses, and means operating downwardly on said bearing block between said guide surfaces for counteracting the upward tilting movements of said mill roll, said bearing block being-provided on the side of lateral stress with a downward extension appreciably below the roll axis'and be-; ing arranged in slidable engagement with one of said vertical guide surfaces above and below the -3. In a deviceof the character described, the" combination with a fixed-frame provided with spaced vertical guide surfaces parallel to each other, of a mill roll rotatableabout a tiltable axis, a bearing block slidably engaging said. spaced parallel guide surfaces, one end of said mill roll being in journalling rotatable engagement with said bearing block and subject to a lateral journal pressure substantially normal to one of said guide surfaces, "and means operating downwardly on v said bearing block between said guide surfaces for counteracting the upwardtilting movements of said mill roll, said means including a pressure block in oscillatable engagement with said hearing block, said bearing block being provided on the side of said journal pressure with a downward extension appreciably below the roll axis and arranged in slidable engagement with said one" of the guide surfaces of said mill roll for mentioned pressure above and below the axis of said mill roll.

4. In a device of the character described, the combination with a floating mill roll rotatable about an axis which is tiltable in a vertical plane and subject to lateral pressure, of abearing box and a floating bearing in said box for rotatably and 'fioatingly upporting said roll, means for applying, pressu e to said bearing for counteracting the vertical axis-tilting movements of said;

above and below the axis counteracting the second-.

mill roll, and a radial arm connected at one end to said bearing and having its other end anchored at a fixed point to support said roll against lateral movements due to said lateral pressure.

5.In a device of the character described, the combination with a fixed frame, of a floating mill roll rotatable'about an axis which is tiltable in a vertical plane and subject to lateral pressure, fixed bearing boxes in said frame and floating hearings in said boxes for rotatably and floatingly supporting said roll and arranged to partake of the axis-tilting movements of said roll, means for applying downward pressure to each of said bearings, and laterally-spaced arms pivotally anchored in said fixed frame and connected to said bearings respectively, said bearings being constructed and arranged to rotatably engage the mill roll journal above and below its axis in all positions of said mill roll to support said roll against lateral movements due to said lateral pressureQ '6. In a device of the character described, the combination with laterally spaced side frames, of a floating mill roll rotatable about an axis which is tiltable in a vertical plane and subject to lateral pressure, said mill roll being provided with axially spaced journals movable vertically in said side frames, bearing blocks constructed and arranged to bear downwardly on said journals respectively in a direction to counteract the axis-tilting movements of said roll, means for applying a downward pressure to each of said bearing blocks, each of said bearing blocks being provided with a bearing surface contacting with one of said journals over an are extending around and below the axis of rotation of said floating roll, and means for movably connecting said journal to the side frame corresponding thereto, said connecting means comprising a shank having one end trunnioned in said side frame, said journal being mounted on the other end of said shank to support said roll against lateral movements due to said lateral pressure.

7. In a device of the character described, the combination with a floating mill roll rotatable about an axis which is tiltable in a vertical plane, and subject to lateral pressure, journals for said roll and bearing blocks constructed and arranged to bear on said journals and to partake of the axis-tilting movements of said roll, means for applying pressure to each of said bearing blocks, said pressure applying means including a pressure block oscillatably contacting with each of said bearing blocks in a surface formed and arroll to support said roll against lateral move-- ments due to said lateral pressure.

8. In a sugar cane mill, the combination with a fixed frame, of a mill roll journalled about a fixed axis in said frame, a floating mill roll rotatable about an axis displaceable automatically towards and away from the fixed axis mill roll rigid member. movably interposed between the two sides of said fixed frame and one end of the floating mill roll, said member being constructed and arranged to transmit pressure from a loadapplying means to said roll end and to transmit the resultant stress due to said load and the reactionary pressure of, the passing mat on said roll to one of the sides of the fixed frame, said member being in normal abutment with the pressure receiving side of said fixed frame along a movable line of contact extending in a plane normal to the frame sides and substantially including the axis of said floating mill roll end said member being in rotary bearing contact with said roll end on opposite sides of said normal plane.

9. In a roll mill of the character described, the combination with a fixed frame, of a pair of rolls journalled about fixed parallel axes in said frame, a third roll rotatable about an axis displaceable towards and away from the common axial plane of the fixed axis rolls under changing thicknesses of the passing mat while the mill is running, a combined guide and bearing for constraining one end of the third roll to movement in a predetermined path, said guide and bearing being in normal sliding bearing engagement with said fixed frame, and said bearing having an upper brass extending on one side of said frame an appreciable distance below the axis of the third roll end, for transmitting lateral pressure components, occurring on that side at right angles to the direction of roll displacement, to said fixed frame in normal and displaced positionsof said roll end.

10. In a sugar cane mill, the combination with a fixed frame, of a roll journalled about a fixed axis in said frame, a second roll rotatable about an axis displaceable automatically towards and away from the first-mentioned roll under changing thicknesses of the mat passing between said rolls while the mill is running, a combined guide and bearing for constraining one end of the second roll to movement in a predetermined path, said bearing and guide being in slidable contact with said fixed frame to transmit to said frame lateral pressures resulting from forces displacing said second roll end in said path and directed in a plane extending normally to the frame sides and substantially including the axis of said end of the second roll, said guide and bearing being on the lateral, pressure side of the roll end in rotary contact with said roll end on opposite sides of said plane, to transmit said.lateral pressures to said frame in every position of the second roll in said predetermined path.

11. A journal for a fioating mill roll, having a vertical and a lateral stress component, comprising a. fixed journal box, a lower brass fixed in said box and an upper brass disposed to move vertically to follow the normal upward movements of said roll, said upper brass extending on the side at which the lateral roll stress is exerted an appreciable distance below the axis of the roll, means for supporting said upper brass against said lateral stresses, and movable pressure means vertically applied against said brass for counteracting the upward stresses of said roll to permit a limited vertical movement of said roll at a desired downward roll pressure.

JOSEPH J. MUNSON.

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