US2727624A - Grading machine - Google Patents

Description

Dec. 20, 1955 DE WITT E. NEIBEL ET AL 2,727,624

GRADING MACHINE Q Filed July 25, 1951 2 Sheets-Sheet 1 I N V EN TOR5. 06 M77 Ne/ Ze/ Ber/7a fl fssma/efler' Dec. 20. 1955 DE WlTT E. NEIBEL ET AL 2,727,624

GRADING MACHINE Filed July 25, 1951 2 Sheets-Sheet 2 INVENTORS. 53914477 5. A e/fe/ United States Patent GRADING MACHINE DeWitt E. Neibel and Bernard H. Essmneller, Kansas City, Mo.

Application July 23, 1951, Serial No. 238,042

9 Claims. 01. 209-104 This invention relates to apparatus for grading fungible materials such as grain and the like according to the relative thickness or diameter of the individual particles, and refers more particularly to improvements in rotary grading machines of the type disclosed in U. S. Patent No. 1,898,249, dated February 21, 1933, and issued on application of John W. Hoefling.

While reference may be had to the above patent for a more detailed description of the principle upon which machines of this type depend for operation, basically they may be said to comprise at least two disks which taper in thickness from a maximum at their centers to a minimum at the periphery and which are coaxially mounted in close arrangement on a rotatable shaft. By virtue of the tapering thickness of the disks, the distance between the proximal faces increases from a minimum near the shaft to a maximum at the outer edge and as the unsized material is fed thereinto, the individual particles will come to rest at a point where the distance between the disks is substantially equal to the thickness or diameter of the particular particle. Thus the fine particles will travel inwardly to a point near the axis of rotation, and the larger particles will range outwardly therefrom, the distance from the center depending in each case on the size of the particle.

In standard machines of this type, the unsized material is fed by gravity from a hopper or other suitable feed means positioned above the disks, becoming wedged between the disks, and through rotation is carried to a point substantially opposite the hopper where it is dislodged and collected in the grades desired. The dislodging and collection is accomplishedthrough the use of stationary fingers which are positioned between the disks to lie in the path of the oncoming particles and which terminate at varying distances from the center of the disks, those designed to catch the finest particles extending substantially to the shaft and the others having their ends spaced at increasing distances therefrom whereby each finger is adapted to catch particles of a designated size. Once dislodged, the particles fall free of the disks, and are directed into suitable receptacles according to the desired grade. The operation of the machine is continuous, and since the only resistance to be overcome in rotating the disks is the friction in the shaft bearings, machines of this type offer a considerable advantage over the previously known vibrating-screen graders or similar devices.

However, while in principle machines of this type represent a marked improvement over previously known devices, a number of problems arise in constructing the machines so that their operational efficiency is at the optimum. In the first place, since the dislodgingfingers are normally rigidly positioned within the space between the disks, and since to insure that all particles traveling in the path intercepted by the fingers will be removed the fingers must necessarily fit closely with the respective faces of the disks, any imperfections either in machining the faces of the disks or aligning them with the nected to any suitable rotary drive means, such as an elec-,

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axis of rotation will cause binding between the fingers and the disks. The binding, 'of course, can be eliminated by narrowing the thickness of the fingers to appreciably less than the spacing between the disks; however, the opportunity then exists for the particles to wedge between the fingers and the disks which may result either in damage to the material being graded or jamming the operation of the machine. I

Broadly speaking, therefore, it is an object of our invention to provide a rotary grading machine of the general type describedabove in which the fingers fit closely within the space between the disks and yet which are selfadjusting to compensate for inaccurate alignment of the disks on the drive shaft or imperfections in the disk faces resulting from improper machining.

Another object is to provide a machine of this type in which the fingers extending inwardly to a point adjacent the drive shaft are separated therefrom by means of a stationary buifer, thus preventing any engagement between the end of the fingers and the rotating shaft. In this connection, it is a further object to provide a buffer which may be installed and removed from the machine with little effort.

Still another object is to provide positive means for controlling the rate at which material is fed between the disks, thus insuring optimum results both as to capacity and accuracy of grading.

Other and further objects, together with the inherent features of novelty, will appear in the course of the following description.

In the accompanying drawings which form part of the specification and are to be read in conjunction therewith, and in which like reference numerals are employed to indicate like parts in the various views:

Fig. 1 is a front elevational view of a machine embodying our inventionjp arts being broken away for purposes of illustration. 5

Fig. 2 is a sectional view taken along line 22 in Fig. 1, in the direction of the arrows.

Fig. 3 is a fragmentary section taken along line 33 in Fig. 2, in the direction of the arrows.

Fig. 4 is a detail view of the dislodging fingers as seen in Fig. 1 showing the method of attachment to their supporting structure, some of the fingers having been removed for clarity of description.

Referring now to the drawings, forming the main body of a gradingmachine embodying our invention is an enclosed casing, preferably constructed of sheet metal, having a bottom wall 10, side walls 12, a rear of back wall 14, and a sectionally canted front wall 16. A troughlike open top hopper 18, partially filled with unsized material 20, such as wheat or the like, spans the top 22 of the casing between the side walls 12, and the forward wall 18a of'the hopper extends downwardly for a short distance into the interior of the casing where it is arced upwardly to form a semicircular lip or trough 1812. P0- sitioned above and fitting closely with the curvature of lip 18b is a horizontally disposed cylindrical member 24 having a plurality of longitudinal grooves or flutes 26 around its periphery to form a star-wheel like gate for controlling the rate of feed of unsized material into the casing. Member 24 is mounted on a coaxial shaft 28 rotatably journaled on opposite sides 12 of the casing in suitable bearings 30, and, as will be discussed more fully hereinafter, is positively connected to the main drive of the machine.

Positioned substantially centrally in the casing and extending from side to side thereof parallel with hopper 18 is a second shaft 32 which is rotatably journaled in the side walls 12 of the casing in bearings 34. One end of the shaft, 32 is provided with a drive coupling 36 contric motor (not shown) and connecting shaft 32 with the star-wheel shaft 28 is a drive chain 38 which passes around toothed sprockets 40 and 42 secured respectively to shafts 23 and 32.

. Encircling shaft 32 within the walls of the casing and connected to rotate therewith by means to be presently described are a plurality of radially tapered disks 44 which are closely arranged to provide between their inwardly converging faces a plurality of annular V-shaped grooves 46. Each disk decreases uniformly in thickness radially outward from its flattened center section 44a, and separating each pair of disks is a relatively thin shim or washer 48 having a diameter substantially equal to the flattened center section 44a of the disks. The periphery 48a of each shim forms the base of each groove 46, and as may be best appreciated from Fi g. 2, the width of the groove increases uniformly outwardly therefrom by virtue of the tapered thickness of each disk.

Referring now more particularly to Fig. 3, forming the means of attachment of disks 44 to shaft 32 is a hublike member 50 rigidly secured to the shaft at one end of the disk assembly and into which are threaded a pair of elongate bolts 52 disposed on opposite sides of and parallel to the shaft. Each of the disks 44 and shims 48 is provided with a pair of diametrically opposed holes corresponding in location with bolts 52, and located at the opposite end of the disk assembly from hub member 50 is a disk-like face plate 54 which is also loosely mounted over bolts 52 and shaft 32, and which may be forced axially toward the hub 50 by means of a pair of nuts 56 mounted on ends 52b of the bolts, thus maintaining disks 44 in tight axial contact along the shaft. In effect, the disk arrangement set out above provides a compact rotor having a plurality of side by side annular V-shaped grooves, and it should be apparent that in the alternative, the same may be accomplished through suitable machining of one solid piece of material. Through the use of disks and the foregoing method of attachment, a grading machine is provided in which the individual disks may be readily detached from the shaft for inspection or replacement with minimum effort.

Returning now to Fig. 2, providing means for feeding unsized material from hopper 18 into the grooves 46 between disks 44 is a plurality of coplanar finger-like members or teeth 58, one for each groove, which are disposed below the upcurved lip 18b of the hopper and which extend downwardly and inwardly between the disks in a comb-like arrangement at an angle of substantially 45. The teeth 58 are mounted in a manner to be prescritly described on a support bar or plate 60 extending transversely through the casing and secured at its ends to side walls 12, and extending downwardly from the top 23 of the casing is a stationary deflection shield 62 for preventing particles being discharged from the hopper from passing downwardly around the support 60 into the bottom of the casing. In this connection, it will be noted from Fig. 1 that since the opposite ends of the disk assembly are spaced inwardly from the side walls 12 of the casing, the space between the end disks and the side wall is blocked off by means of filler plates 64 rigidly secured to the casing Wall and cut out around the shaft 32 and hub 50. The inner face of each filler plate 64 is faced as indicated at 66 with a soft material such as felt to prevent wear during rotation.

Positioned on the opposite side of the disk assembly from feed teeth 58, and extending upwardly and inwardly into grooves 46 between disks 44 are a plurality of dislodging teeth 68 which are arranged in three parallel banks according to length. Similarly to feed teeth 58, the teeth 68 of each bank are mounted in a manner to be presently described on a stationary support bar 70 secured at its ends to the side walls 12 of the casing, and are tapered in thickness to correspond with the tapered width of grooves 46 (see Fig. 1). The teeth 68 of each bank are of equal length, and as shown in the drawings, those in the lower bank extend inwardly substantially to the bottoms of the grooves 46 while those in succeeding banks terminate at increasing distances therefrom. Thus, the particles carried between disks 44 are intercepted by the teeth according to their radial spacing from the axis of rotation, and are directed into separate discharge passageways 72 below the support bars 60 formed by partitions 74 extending transversely through the casing.

Forming a novel feature of our invention is the means of attachment of the feed teeth 58 and dislodging teeth 68 to their respective support bars 60 and 70. As is particularly evident from Fi g. 2, provided in the lower surface of each tooth near its outer end is a small rectangular notch or slot 53a, 68a, which is slightly wider than and loosely engaged by a shoulder-like key 60a, 7%, extending lengthwise of and secured to the upper surface of the support bars as, (see Fig. 4). To hold the fingers down on the support bar, a cover plate 76 having a generally L-shaped cross-section is positioned above the teeth and secured to the support bar by bolts 78 and nuts 80. In order to prevent binding between the cover plate 76 and the teeth 58, 68, a spacing bar 82 having a thickness slightly greater than the vertical thickness of the teeth is interposed between the cover plate and the support bar outwardly of the ends 58b, 68b, of the teeth. It should be evident from the foregoing that while the teeth are prevented from longitudinal movement by key 60a, 70a, they are still free to shift axially of shaft 32 and to pivot slightly about the key 60a,70a in the channel formed by cover plate 76 and the support 70. Thus, should the disks 44 be out of alignment With shaft 32, or should there be any imperfections in machining the faces of the disks, the lateral play aflorded by the key 60a, 70a, and slots 58a, 68a, will permit the teeth to adjust themselves accordingly. The edges 76a of the cover plate 76 extend inwardly to lie closely adjacent the periphery of disks 44 to prevent particles from falling between the teeth 58, 68, as they travel to or from the grooves 46, and are slightly tapered in thickness for smooth passage of the particles thereover.

Forming another novel feature of our invention is the provision of means for providing a tight seal between the ends of the feed teeth 58 and lower bank of the dislodging teeth 68 and the periphery 48a of the rotating shims 48 carried between each pair of disks 44. As may be best appreciated from Figs. 2 and 3, hooked over the top of each shim 48 is the curved end 84a of a relatively thin J-shaped buffer plate 84 which is provided with an elongated stem extending downwardly and rearwardly away from the axis of rotation. The stems of the buffer plates 84 are attached externally of grooves 46 to a shaft-like support 86 paralleling shaft 32 and affixed at its ends to the side walls 12 of the casing. Concentric with the shaft 32, the inner edges of the buffer plates 84 rest in sliding contact with the shim peripheries 48a, and the ends of the stationary teeth 58 and 68 bear against the outer edge of the buffer plates; thus any tendency of the fingers to dig into the shims which might result from attempting to maintain them in close contact therewith is effectively eliminated.

The operation of our invention should be fairly evident from the foregoing description. As the disk assembly is rotated in the direction shown by the arrow in Fig. 2, shaft 28, driven by chain 38, rotates feed member 24 in the direction shown by the arrow, and the unsized material 20 is fed from hopper 18 into the casing and onto the surface of cover plate 76 covering feed teeth 58. Traveling down the feed teeth 58, the particles distribute themselves according to size in the tapered grooves 46 between the disks 44, and becoming wedged therein, are carried through substantially a half revolution where they are intercepted by the dislodging teeth 68. Removed from between the disks 44 by teeth 68, the particles intercepted by the respective banks fall over the ends of the cover plates 76 into passageways 72 and are collected by any suitable means. By virtue of the positive connection of feed memher 24 with the rotating disk assembly, 'the material is fed between the disks at a rate which insures against clogging of the grooves and failure to distribute properly therein. The relatively close fit between the disks and the sides of the feed teeth 58 and dislodging teeth 68 prohibits the wedging of particles therebetween, and the tight seal at the inner ends of the teeth afforded bybuffer plates 84 prevents fragments or extremely fine particles from falling into the bottom of the casing. During rotation of the disk assembly, the teeth 58 and 68 are free to adjust themselves laterally (as has hereinbefore been pointed out), thus allowing them to be more accurately fitted into the grooves than if they were held rigid. Through the self-adjusting mounting of the teeth, the accurate fitting of the teeth into the grooves, and the positive control of the rate of feed, a grading machine is provided which assures of the accurate separation of the particles according to their thickness or diameter and in which the rate at which materials may be graded is maintained at the optimum.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the invention.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illus-. trative and not in a limiting sense.

Having thus described our invention, we claim:

1. In a grading machine, a generally cylindrical rotor mounted to turn about a horizontal axis, said rotor containing a plurality of annular grooves disposed side by side along the length of the rotor, the opposite side walls of each groove converging toward the center of the rotor whereby the groove is substantially V-shaped in radial cross section, a support fixedly positioned adjacent the periphery of the rotor, a plurality of coplanar laterally spaced teeth projecting from said support into the respective ones of said grooves, said support comprising a channel having parallel side walls, said teeth having shank portions loosely confined between said side walls for sliding movement relative thereto, whereby each tooth has a side surface confronting the interior surface of one of said side walls, a slot in one of said surfaces paralleling the axis of the rotor, a key on the other of said surfaces also paralleling the axis of the rotor and projecting into said slot to substantially prevent sliding movement of the tooth in the direction of its longitudinal axis while permitting movement of the tooth parallel to the axis of the rotor, and each tooth tapering toward its tip to conform to the side walls of the groove into which it extends.

2. A machine as in claim 1 wherein said slot in each tooth is slightly wider than said key whereby said tooth enjoys limited free pivotal movement relative to said support.

3. In a grading machine, a generally cylindrical rotor mounted to turn about a horizontal axis, said rotor containing a plurality of annular grooves disposed side by side along the length of the rotor, the opposite side walls of each groove converging toward the center of the rotor whereby the groove is substantially V-shaped in radial cross section, a buffer in each groove at least partly encircling the axis of the rotor, each buffer having a bearing surface curved circumferentially of the rotor to conform with and seat against the base of the groove, means for anchoring said buffers against rotation with the rotor, a support fixedly positioned adjacent the periphery of the rotor, a plurality of coplanar laterally spaced teeth projecting from said support into the respective ones of said grooves and having their tips abutting against said butfers .in the respective grooves, each tooth tapering toward its tip to conform to the side walls of the groove into which it extends, each tooth mounted on said support for limited sidewise movement independently of the other teeth, and coacting elements on the teeth and support substantially preventing the teeth from moving longitudinally relative to said support.

4. In a grading machine, a generally cylindrical rotor mountedto turn about a horizontal axis, said rotor containing a plurality of annular grooves disposed side by side along the length of the rotor, the opposite side walls of each groove converging toward the center of the rotor whereby the groove is substantially V-shaped in radial cross section, a bufier in each groove at least partly encircling the axis of said rotor, each buffer having a bearing surface curved circumferentially of the rotor to conform with and seat against the base of the groove, means for anchoring said buffers against rotation with the rotor, and a comb-like member mounted beside the rotor with its teeth projecting into the respective grooves, the tip of the tooth in each groove abutting against the buffer in that groove.

5. A machine as in claim 4 wherein each buffer comprises a J-shaped member having a curved end concentric with the axis of the rotor and an elongated stern projecting outwardly from said end to a point beyond the periphery of the rotor, and said anchoring means comprising a stationary support beside said rotor having the projecting portion of said stems connected thereto.

6. In a grading machine, a generally cylindrical rotor mounted to turn about a horizontal axis, said rotor containing a plurality of annular grooves disposed side by side along the length of the rotor, the opposite side walls of each groove converging toward the center of the rotor whereby the groove is substantially V-shaped in radial cross section, a buffer in each groove at least partly encircling the axis of the rotor, the buffer in each groove having a bearing surface curved circumferentially of the rotor to conform with and seat against the base of the groove, means for turning the rotor, means anchoring said buffers against rotation with the rotor, a comb-like member mounted beside said rotor with its teeth projecting into the respective grooves, said teeth being inclined downwardly toward their tips and the tips of the teeth abutting said buffers in the respective grooves, means for feeding unsized material along said teeth into said grooves, and a second comb-like member mounted beside said rotor in a position substantially opposite the position of said first member, said second member having stripping teeth extending into the respective grooves.

7. A machine as in claim 6 wherein the tips of the teeth of said second comb-like member abut against said buffers in the respective grooves.

8. In a grading machine, a generally cylindrical rotor mounted to turn about a horizontal axis, said rotor containing a plurality of annular grooves disposed side by side along the length of the rotor, the opposite side walls of each groove converging toward the center of the rotor whereby the groove is substantially V-shaped in radial cross section, a buffer in each groove at least partly encircling the axis of the rotor, the bufifer in each groove having a bearing surface curved circumferentially of the rotor to conform with and seat against the base of the groove, means for turning the rotor, means anchoring said buffers against rotation with the rotor, a comb-like member mounted beside the rotor with its teeth projecting into the respective grooves, said teeth being inclined downwardly toward their tips and the tips of the teeth abutting .said buffers in the respective grooves, a hopper above said rotor adapted to receive unsized material to be graded, said hopper having above said member a discharge opening elongated in a direction parallel to the axis of the rotor and substantially coterminous therewith, a closure for said opening comprising a fluted cylinder mounted to turn about an axis parallel to the axis of the rotor, a drive connection from said rotor turning means to said cylinder whereby said cylinder is adapted to feed the unsized material from said hopper onto said comb-like member at a rate dependent upon the rate of rotation of the rotor, said material adapted to flow downwardly along said inclined teeth into said groove, and a second comb-like member mounted beside said rotor in a position substantially opposite the position of said first member, said second member having stripping teeth extending into the respective grooves.

9. In a grading machine, a generally cylindrical rotor mounted to turn about a horizontal axis, said rotor containing a plurality of grooves disposed side by side along the length of the rotor, the opposite side walls of each groove converging toward the center of the rotor whereby the groove is substantially V-shaped in radial cross section, a support member substantially parallel with the axis of the rotor and fixedly positioned adjacent the periphery of the rotor, a plurality of coplanar laterally spaced teeth extending from said support into the respective ones of said grooves and having their inner ends spaced from the bases of said grooves, the teeth being tapered to conform to the side Walls of the respective grooves into which they extend, a member cooperating with said support member and said teeth to prevent movement of said teeth transverse to the plane of the teeth while permitting free sidewise movement of each tooth in the plane of the teeth independently of the other teeth, and coacting elements on the teeth and support substantially preventing the teeth from moving longitudinally Within the grooves thereby to preserve the spacing of the inner ends of the teeth from the bases of the grooves.

References Cited in the file of this patent UNITED STATES PATENTS 110,124 Douglas et a1. Dec. 13, 1870 558,900 Dougan Apr. 21, 1896 631,093 Richards et a1. Aug. 15, 1899 836,869 Deaver Nov. 27, 1906 1,541,903 Crites June 16, 1925 1,898,249 Hoefiing Feb. 21, 1933 1,899,737 Ulrich Feb. 28, 1933 1,941,147 Hans-Joachim Jonlige Dec. 26, 1933 2,091,815 Hommel Aug. 31, 1937 FOREIGN PATENTS 442,269 Great Britain Feb. 5, 1936 600,345 Germany July 20, 1934 615,179 Germany June 28, 1935 640,610 Germany Jan. 8, 1937

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