US2738135A - Roller mill with worm gear drive, operable through a range of adjustment positions of the rollers - Google Patents

Description

March 13, 1956 T. G. CECKA 2,733,135

ROLLER MILL WITH WORM GEAR DRIVE, OPERABLE THROUGH A RANGE OF ADJUSTMENT POSITIONS OF THE ROLLERS Original Filed Jan. 17, 1947 5 Sheets-Sheet 1 L F I I l /2 15 L4 "/3 l l I l x 2/9 rr- H [5L 7 4 I 6/ 49 i 26/ 4 52 i 44 47 J7 r-- --1 M ii 60 5 I i //05 6 I l 15:11:11" :r 90 48 "J3 H07 4-D- I 6 Z 3 INVENTOR.

c V 77/0MA$ G. CECKA M WW ATTORNEYS March 13, 1956 3 v pm 8 h 3 w II, 2W6 m m S T5 T. G. CECKA ROLLER MILL WITH WORM GEAR DRIVE A RANGE OF ADJUSTMENT POSITIONS OF THE ROLLERS Original Filed Jan. 17. 1947 INVENTOR.

77-/0MA5 G. CECKA fie. 2 By ATTORNEYS March 13, 1956 T. G. cEcKA 2,738,135

ROLLER MILL WITH WORM GEAR DRIVE, OPERABLE THROUGH A RANGE OF ADJUSTMENT POSITIONS OF THE ROLLERS Original Filed Jan. 17. 1947 5 Sheets-Sheet 3 z JO" i i I 33-" l! 6 I IG INVENTOR.

7710MA$ G. CECKA OQ Z, f d W A TTORNEYS March 13, 1956 T, CECKA ROLLER MILL WITH WORM GEAR DRIVE, OPERABLE THROUGH A RANGE 0F ADJUSTMENT POSITIONS QF THE ROLLERS Original Filed Jan. 1'7, 1947 5 Sheets-Sheet 4 m mm TC m. m M M m w W m w ,0 M m Wm B Z w wh GN N m NEW POLLS OLD ROLLS W WW March 13, 1956 CECKA 2,738,135

ROLLER MILL WITH WORM GEAR DRIVE, OPERABLE THROUGH A RANGE OF ADJUSTMENT POSITIONS OF THE ROLLERS Original Filed Jan. 17. 1,947 5 Sheets-Sheet 5 INVENTOR.

7/:2OMAS G. CEOKA fwd, WMQQKKW ATTORNEYS United States Patent "ice ROLLER MILL WITH WtC RM GEAR DRIVE, OPER- ABLE THROUGH A RANGE OF ADJUSTMENT POSITIONS OF THE ROLLERS Thomas G. Cecka, Minneapolis, Minn., assignor to inter national Milling Company, Minneapolis, Minn., a corporation of Delaware Original application January "17, 1947,'Serial No. 725,392. Divided and this application August 24, 1951, Serial No. 243,418

4 Claims. (Cl. 241-230) This invention relates to roller mills and more particularly to improvements in the construction of roller mills of the type used in the milling of dry, pulverulent material, such as grain, feeds, mill products, salts, pharmaceuticals and the like.

The present application is a division of my application Serial No. 725,392 filed January 17, 1947.

Roller mills have long been used for the breaking and milling of dry material, and in the grain milling and other industries have been widely used in batteries of many mills operating in parallel. In such installations it has been common to provide a line shaft for supplying power to a battery of mills, each mill or mill stand, as it is sometimes designated, being driven by a belt to the common line shaft, and the mills have been designed to accommodate such drives.

While these mill installations are satisfactory and have served to mill countless tons of materials, they are subject to many serious defects due to the type of installation required and due to their inherent mechanical construction.

One of the most serious defects in the common belt driven mill stand arises out of the common drive. Since all mills were of necessity belted to a common line shaft any opera tional defect necessitating servicing of one mill has frequently required a shut-down of the entire drive shaft and all mills connected toit. Furthermore, the belt drive itself, has involved relatively short belts with consequent high belt tensions in order .to deliver the required horsepower, and this has led to defects in operation occasioned by bearing failure, misalignment of the roll, damaged rolls, etc. In addition, heavy stress of the belts is transferred from the mill to the building in which it is housed.

it is an objectof the present invention to provide an improved roller mill wherein an individual drive is provided for each mill and furthermoreto provide an improved gear drive between the'motive power source and the slow and fast rolls of the mill.

Other defects of the present mills have arisen out of their construction wherein the cooperating fast and slow rolls are situated at'equal levels. .In such'roller mills the entire thrust of the rolls, occasioned by the pressure of the material being milled between them, has had to be carried by the roll shaft bearings, and this bearing load,

taken with the added load'due to belt tension of thedrive, has been the cause of frequent operational 'dificulties. It is an object of the presentinvention toprovide an improved roll mill wherein the thrust due to material pressure on the rolls while milling is at least partially cornpensated by the weight of the roll itself so as to relieve in part the excessive load on the bearings of the mill.

Another serious objection to conventional mills is the fire hazard and employee hazards occasioned by the belt drives employed for driving the. rolls. "It is an object of the invention to eliminate vthese haizards by providing a self-contained ,gear drive unitin-which the roll drive Y e ts ar assisted-s l wh h ameness. 'free q 2,738,135 Patented Mar. 13, 1956 danger due to the ignition of dust by static electricity on the belt and free from danger to employees. It is a further object to provide an improved self-contained milling unit wherein all working stresses are within the unit itself and not communicated to the building as with belt driven mills and which-is free fromthe vibration which has commonly been encountered .due to large rotating pulleys in belt driven mills.

It is also an object of the invention to provide an improved roller mill wherein'the rolls are driven by-direct .mechanical gear connection'from .a motive power source and at the same time provision made for wide variations in adjustment of the rolls to compensate for wear of the rolls with efficient geardrive connection being maintained the while.

It is a further object of the invention to provide an improved mill wherein the fast roll ispositioned above and partially overlying the slow roll so as to eliminate the necessity for tramrningthe rolls (i. e. maintaining precise parallelism) under milling conditions.

'It is a further object to provide an improved gear drive wherein shorter shafting is provided. This reduces bowing of the roll shafts and torsional strains which were common causes of failures with the rather long roll shafts needed in belt driven mills.

Other and further objects of the invention are those inherent in the apparatus herein illustrated, described and claimed.

The invention is illustrated with reference to the drawings in which- Figure l is a side elevational view of the machine with certain parts removed;

Figure 2 is an end elevational view taken in the direction of arrows 22 of Figure '1 showing the drive gears exposed and their enclosinghousing removed;

Figure 3 is a sectional view taken in the direction of arrows*3'3 of'Figure 1;

Figure 4 is *afragmentary sectional view taken along the lines and in the direction of arrows 4-4 of Figure 1 illustrating the position of the rolls when they are new;

Figured is a fragmentary sectional view corresponding to Figure-4, likewise taken along the'line and in the direction of arrows 4- 4 of Figure 1, illustrating the rolls after they have been reduced in "diameter during their service life;

Figure 6 is an enlarged detail of the adjusting mechanism for moving one of the roll shafts and is representative of the mechanism used for adjusting the ends of the rolls; and

Figure 7 is a fragmentary sectional view through the quick throw-out lever and the associated cam.

Throughout the drawings corresponding numerals refer to the same parts.

Referring to the drawings the machine comprises a frame and housing generally designated 10 having end plates 11 and 12 and back and front plates 13 and 14. The housing may be cast or fabricated of any suitable materials and is preferably provided with a'bolting flange at 15 and 16 by which the machine can be bolted to the milling floor. The upper portion of the plate 14 converges inwardly at'19 and thence is shaped in to form the'top 20 which is providedwith a supply chute 21. The upper portion of back plate 13 terminates in housing 35'. A second back plate 18 is provided whichconnects the top of housing 35 to the rear edge of top 20. Plates 13 and 18 may be integral with housing 35 or separate members therefrom.

The interiorspace. of the housingisprovided with a slantingbaffle 23 which, together with the vertical vbafile board 24, forms-a hopper. Bat- fies 23 and 24 extend from one end plate-11 to theother end plate 12 and form an interior hopper so that the material being fedxfiowsin (3 the direction of arrow onto the feed roll 26. The feed roll is of relatively small diameter and serves almost to close the bottom space 27 formed by the converging bafiles 23 and 24.

Feed roll 26 is mounted upon the feed roll shaft 29 which is journalled in the end plates 11 and 12 and extends outwardly beyond rear end plate 11 and carries a relatively large diameter pulley 30, as shown in Figure 1. Feed roll 26, its shaft 29 and pulley 30 rotatein the direction of arrow 31, being belt driven as hereinafter described. Likewise, within the housing there are pair of downwardly extending and converging balties 32 and 33. Inclined baffle 32 extends from the wall 14 and vertical bafile 33 extends from housing 35. At their awer ends bafiles 32 and 33 form a chute space 34 which is connected to a delivery chute leading to classifying machinery below the milling fioor. The converging chute formed by the baffles 32 and 33 collects the milled ma terial as hereinafter described and thus delivers it from the mill.

At the center of the machine, as shown in Figure 2, there is a motor housing enclosure or tunnel 35 which extends from end plate 11 to end plate 12. The housing has a bottom portion 36 and sides 37 and 38 which con verge upwardly at their top portions 39-39 at an angle. The inclined face 40 of side 37 is of such a surface and pitch that the milled material will not lodge thereon. The motor housing tunnel 35 is formed integrally with the end walls 11 and 12 and is suitably supported by interior bracing not illustrated. The end Walls 11 and 12 are, of course, provided with opening plates on the ends of the tunnel 35 and these plates are provided with louvers 41 so as to allow through ventilation from one end to the other for cooling the drive motor therein. The motor which is mounted in tunnel 35 is thus completely isolated from the milled material falling downwardly within the hopper space formed between the bafiles 32 and 33 and housing Wall 37. From the motor 50 there extends a shaft 43 carrying a main drive gear 42.

Within the main housing there are also positioned two milling rollers 44 and 45, each roller being provided with a shaft upon which it is journalled. The shaft 46 carries roll 44 and extends through stufling boxes 47 and 49 in the end plates and is journalled upon pillow block 51 which is mounted upon end plate 11 and pillow block 52 which is mounted upon plate 12. The bearing carrying the shaft 46 and hence the roll 44 is journalled upon fixed journals which do not move in respect to the end plates 11 and 12. Hence, the axis of rotation of the roll 44 remains fixed throughout its service life.

Roll 45 is supported upon shaft 48 which likewise extends out through stufiing boxes in the end plates 11 and 12 and is supported by journals 53, one of which is illustrated in Figure 3 and a corresponding journal at the other end of the machine. These journals are mounted upon a frame 54 having a T-slot connection to a correspondingly shaped slide 55 solidly attached to the end plates 11 and 12. The journals at each end of the machine carryng the roll shaft 48 of roll 45 is thus permitted to move in a plane transverse to the machine, the plane being at lines 56-56. Suitable sliding stuffing boxes are provided at each end of shaft 48 where it passes through the end plates 11 and 12 which keeps dust from the milling operation from passing out of the mill around the shafts. The stuifing boxes are either split diametrically or are made so as to lift from the machine frame, so as to allow removal of the rolls and their shafts and gears when the mill frame is opened as hereinafter described.

Figure 3 shows the slide 55 which is permanently fastened to end plate 12. Figure 1 also shows the slide 55 which carries journal 53 adjacent end plate 12. It is to be understood, of course, that the journal, not illustrated, adjacent end plate 11 and at the far end of shaft 48, is likewise mounted upon a slide exactly similar to that shown at 55 in Figure 3. The journal constructions for the shafts 48 and their adjustments hereinafter described are identical at each end of the machine and therefore 1t 15 only necessary to describe in detail the construction adjacent the end plate 12. v p 7 Referring to Figure 3 the slide 55 carries the frame 54 so that the frame 54 carrying the journal 53 may move in a translatoi'y motion back and forth in the direction of the double arrow 58-. Thus, journals 53 can move back and forth and hence" carry the shafts 48 in a transvets c: plane at the level of line 56-56. The degree of such movement permitted in the machine is sufiiclent to accom= moth... not only the desired opening of the mach ne for clearing any jams that may occur, but also sufiicient to permit the movement of roll 45 more closely ad acent roll 44, so as to maintain the desired close clearance for milling as the rolls are reduced in size during their service life. It may be pointed out at this juncture that m Ordl' nary milling practice for flour milling machinery, the rolls 44 and 45 are approximately nine inches in diameter as initially manufactured. The rolls may be smooth or corrugated (rough), depending upon the type of milling effect desired. As the milling takes place, there is soine wear on the roll and it is customary to remove the rolls from the machine from time to time and re-finish them to true and accurate diameter throughout their length and to re corrugate them when corrugations are desired. Th1s effects an overall i'eductidn in the diameter of the roll and compensatory adjustment must therefore be prov ded to maintain desired close clearance for milling. Figure 4: represents the position of the rolls set close as during milling when the rolls are of maximum diameter when new. Figure 5 in the full line position illustrates the position of the rolls likewise set close for milling but after they have been reduced in diameter during the SEI'VICG life. The dotted lines in Figure 5 illustrate the position of the rolls when they are new and corresponds thus to the full line showing of Figure 4.

Figure 3 and Figure 6, which is an enlarged view of mechanism for shaft 48, illustrate the mechanism for adjustment of the adjustable roll 45. For this purpose there is provided a shaft 59 and another shaft coaxial with it at the other end of the machine. Both shafts are mounted on their adjacent end plates. Upon the shaft there is mounted an oscillatable lever 60 having a handle portion 61; the lever carries an eccentric 62 to which is attached eccentric link 63, which serves to move bearing 53 and hence roll 45 back and forth in a horizontal plane. The link 63 has a threaded connection at 64 to the rod 65, and rod 65 extends through a cylindrical space 66 in the bearing frame 54 and thence to termination at the hand wheel 68 which is solidly mounted on rod 65. By turning the hand wheel 68 the rod may be threaded more or less into the threaded connect on 64. Upon the rod 65 there is mounted sleeve 69 which is threaded at 70 upon the rod 65. The threads 64 are fine threads and 70 are coarse threads. Hence, by rotating rod 65 by means of hand wheel 68 the sleeve can be moved axially in respect to link 63. A locking nut hand Wheel 71 is threaded on shaft 65 at threads 70 and by turning wheel 71 tight, any adjustment of the sleeve 69 on rod 65 can be fixed. Sleeve 69 has a nut at 73 and an internal collar at 74. Spring 75 bears against the collar 74 and against the end Web 76 of the cylinder 78 By initially turning up nut 73 the spring 75 may be ad usted to a given compression. A cover plate 79 serves as a journal around sleeve 69 and closes the cyllndncal space 66. Cover plate 79 is held onto the cylinder 78 by several cap screws.

The hand lever is first moved against right-hand stop 80 to roll closed position in which the eccentric link 63 is moved to the left with reference to Figure 6. Then by rotating the hand wheel 68, it is possible to vary the position of sleeve 69 with reference to link 63 and move the periphery of roll 45 towards the perlphery of roll 44 for proper grinding. During this adjustment, spring ram-n i 75 holds Web 76 against nut 73. "The adjustment may be locked by tightening 'handwheel 71. As' milling pressure (i. e. the pressure exerted by the'material being ground) develops, this may be sufficient to compress spring 75 further andmove the entire journal 53 outwardly from the vertical center line of the machine and along rod 65. When this occurs a'clearance will develop between nut 73 and web 76. To maintain a given vfineness of grind a readjustmentof the-wheel 68 may be required so as to changethe position of journal 53 while the mill is operating and the milling pressure is on. In any event spring 75 will compress and permit hard obstacles to be cleared by the rolls. =In-or'der to'r'nove the roll 45 quickly away from roll 44, handle 60 is moved in the direction of arrow 82 against left-hand stop 81. When the handle 60 is moved in the direction of arrow 82, the entire bearing support 53 is quickly moved towards the wall 14 of the machine by the action of eccentric 62 through link 63 and rod 65 and thus roll 45 is thus quickly moved'away from roll 44 so as to clear any obstruction that may have developed therebetween. The bearing construction on the far end of the machine (plate 11) is exactly analogous and by means of its hand-lever, the rolls 44 and 45 may be quickly moved to clear position at that end. Usually the hand levers at the two ends of the machine are connected together by linkages for simultaneous movement so that by pulling the lever on either end of the machine, therolls may be quickly separated. Since the adjustments at the two ends of the machine are independent, it is possible to maintain accurately the uniform clearance between the rolls 44 and 45, regardless of irregularities in operation of the mill. This is called tramming, i. e. maintaining the rolls parallel. Since the fixed fast speed roll 44 of the present mill diagonally overlies the adjustableslow speed roll 45 and the roll 45 is movable in a horizontal plane through the machine, muchless critical parallel adjustment or tramming is required, as compared with older mills in which the rolls are on the same level. Each end 11 and 12 is preferably provided with stops 80 for limiting the movement of lever 60 in its open and operating positions.

Within the machine housing there is provided an adjustable bafiie 84 which serves to direct the downwardly falling material directly into the nip of the rolls 14-45. The grain falls downwardly from the feed roll 26 in the general direction of arrow 85 and is directed by the baffle 84 into the nip space between the differentially revolving rolls. 6

The mechanism for rotating the rolls is illustrated in Figures 1 and 2. The motor. shaft 43 is provided with a spiral gear 42 mating with a corresponding spiral gear 86 on countershaft 87. The shaft 87 is supported in a plurality of bearings 88 and is therefore rotated by the gears 42 and 86 at approximately motor speed. Upon shaft 87 there is a herringbone gear 89 which mates with a corresponding herringbone gear 90 upon the countershaft 91 which is likewise supported by the bearings 92. Since the gears 89 and 90 are approximately the same diameter the countershaft 91 is likewise rotated at approximately motor speed. At the end of the shaft 91 there is provided a spiral gear 93 which mates with the spiral gear 94 on the end of roll shaft. The gear pair 93-94 affords approximately a l to 1 gear ratio and therefore the roll 44 is rotated'at approximately motor speed. By suitably selecting the angle of the gears 93-94, the fast roll 44 may be caused to rotate in the direction of arrow 95. With such rotation the countershaft 91 rotates in the direction of arrow 96 and countershaft 87 rotates in the direction of arrow 97, the motor being rotated in the direction of arrow 98.

Upon shaft 87 there is provided spiral gear 100 which mates with a relatively larger spiral gear 101 causing the latter and the roll shaft 48 and rolls which they drive to be rotated in the direction of arrows 102, but at a much lower speed than the rotation of roll 44. By appropriate selection'of the gear ratio of the gear pairs -401, the roll 45 can be caused to rotate at any desired speed relative to the speed of roll 44, and accordingly the desired relatively peripheral velocity for adequate grinding of various materials can be varied to suit the conditions needed in the particular grinding operation under consideration.

Gear 100 is made relatively long and since it is of uniform pitch diameter throughout its length, it mates precisely with the gear 101, regardless of the adjustment position of the latter gear as determined'by the position of its bearing block 53. Therefore, the bearing block 53 and the corresponding hearing at the opposite end of the machine may be moved by the quick opening handle 60 and their position may be adjusted by the hand wheel 68 and the corresponding adjustment wheel at the opposite end of the machine as desired, without disturbing the precise mating of the gears 100 and 101. Furthermore, as the rolls are reduced in diameter as shown in Figures 4 and 5, thus requiring the closer together setting depicted in Figure 5, this fact likewise does not affect the accurate mating of the gear 101 upon its driving gear 100, since the gear 131 simply operates at a position on gear 100 which is a little closer to the center of the mill.

Referring to Figures 4- and 5, particularly, the pressure caused by the grinding of material between the rolls 44 and 45, for example, is in the direction of arrows 103 and 104. The force of arrow 104 has an upward component 105 which'therefore merely tends to lift the weight of the roll 44, or stated another way the weight or" the roll 44 tends to maintain the milling pressure upon the cooperating roll 45. This is a distinct advantage as compared with-earlier mills whereinthe entire milling pressure had to be sustained by the bearings carrying the roll shafts. Fin-addition, the elimination of the drive belts and the provision of a geared drive reduces bearing pressure, permits the use of shorter shafts which consequently distort less under load, reduces fire hazard and employee hazard, and at the same time greatly reduces vibration and the transmission of vibratory and belt stress to the building carrying the mill.

Referring. to Figure 1 the entire gear train for driving the rolls from the motor, together with the countershafts is preferably enclosed in a suitable gear housing shown by the dotted lines 106 which is suitably supported from the end plate 12 of the mill. The housing has not been shown in detail since it will be understood adequately to enclose the gears so as to permit their complete lubrication during operation. Likewise the bearings of the various countershafts are intended merely as illustrative, it being understood that adequate bearing supports will be provided on one or both sides of each gear in order to sustain the loads encountered during service. At the rear end of the mill the shaft 46 protrudes outwardly beyond its bearing and is provided with a V-belt pulley 107 which serves to drive the belt 108 and thus propel the material feed roll pulley 30. The feed roll thus i operated at relatively low speeds whenever the mill is in operation. The main housing of the mill and also the gear drive housing 106 are provided with removable sections which separate along suitable planes, so as to permit the rolls 44 -45, their shafts and drive gears, to be lifted bodily from the mill for renewal or replacement.

As many apparently widely dilferent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments herein.

What I claim is:

1. A roller mill comprising a frame, a substantially horizontal roller journalled for rotation in said frame, a second roller journalled on said frame, the axis of said first roller being parallel to and offset from a vertical plane passed through the axis of said second roller, means mounting said second roller for movement in a transverse plane through said frame through a range of adjustment.

positions sufiicient to position the peripheries in spaced relation or close proximity regardless of reduction in the size of the rollers during their service life, a first power shaft extending horizontally across the frame and gear means connecting it to the first roller for driving the same, a second power shaft extending across the frame and gear means connecting it to the second roller for driving the same, gear means connecting the first and second shafts and a motor mounted on the frame and connected to drive the shafts for driving said shafts simul taneously at diverse speeds.

2. The apparatus of claim 1 further characterized in that the power means is an electric motor having a gear connection to the second countershaft, said second countershaft being geared to the first countershaft.

3. The apparatus of claim 1 further characterized in that said first roller is placed in an elevated position and the first and second rollers are geared so that the upper surfaces of the cooperating first and second rollers rotate towards each other with the periphery of the lower roller moving at a lower speed that the adjacent cooperating periphery of the upper roller.

4. A roller mill comprising in combination a frame, a first substantially horizontal roller journalled for rotation in the frame, a second substantially horizontal roller journalled for rotation in the frame, the axis of said first roller being parallel to and vertically spaced with reference to the axis of said second roller, a motor mounted on said frame, gear means connecting said motor to a first power shaft, gear means connecting said first power shaft to a second power shaft, gear means connecting said second power shaft to said first roller for rotation thereof, at least one end of said second roller being mounted in a horizontally slidable journal supported on a track posi tioned on said frame, gear means connecting said first power shaft to said second roller for rotating said second roller in a direction of rotation opposite that of said first roller, means whereby said second roller will rotate at a slower speed than said first roller, a lever movable from a first to a second position, said lever including a cam connected to a first link, a second link connecting said first link to said slidable journal, said second link being axially adjustable with reference to said first link, adjustable means connecting said second link to said journal, means locking said second link to said journal in adjusted position, a spring connection between said second link and said journal and means for adjusting the tension of said spring connection.

References Cited in the file of this patent UNITED STATES PATENTS 199,605 Wegmann Jan. 22, 1878 240,453 Oexle Apr. 19, 1881 255,860 Holt Apr. 4, 1882 335,257 Van Gelder Feb. 2, 1886 411,404 Wagner Sept. 17, 1889 447,951 Kapler Mar. 10, 1891 459,352 Wagner Sept. 8, 1891 1,130,365 Altheide Mar. 2, 1915 1,199,938 Sorenson Oct. 3, 1916 1,709,018 Howson Apr. 16, 1929 1,713,487 Lorrance May 14, 1929 2,022,135 Newhouse Nov. 26, 1935 2,107,214 Rechtin Feb. 1, 1938 2,254,512 Brasington Sept. 2, 1941 2,293,670 Sickman Aug. 18, 1942 FOREIGN PATENTS 1,107 Great Britain Jan 24, 1888 1,179 Great Britain Mar. 5, 1883 6,990 Austria Mar. 10, 1902 12,087 Great Britain of 1909 344,019 ltaly Oct. 21, 1936 460,505 Great Britain Jan. 28, 1937 487,759 Great Britain June 24, 1938 539,846 France July 1, 1922 542,532 France May 18, 1922

Images