US1232052A - Grading or screening apparatus. - Google Patents

Description

E.E.LANDAHL. GRADING 0R SCREENING APPARATUS.

. APPLICATION FILED DEC. I8. 1916. lh Patented my s, 1917.

E. E. LAND/RHI..

GRADING 0R SCREENING APPARATUS.

APPLICATION FILED 050.18. ISIS.

l 923%@520 Patented July 3, i917.

4 SHEETS-SHEET 2.

@TQQ/LE.,

E. E. LANDAHL.

GRADING 0H SCREENING APPARATUS.

APPLICATION FILED DEC- IIL-ISIS.

LQSQD Patented July 3, 1917.

4 SHEETS-SHEET 3A E. E. LANUAHL.

GRADING 0R SCREENING APPARATUS.

APPLICATION FILED DEC. I8. 1916.

I Q l Paten-ted July 3,1917.

4 SHEETSSHEET 4.

sg 5m 12T UNTEU STATES PATENT @lltmlhllflltdo EUGENE E. LANDAIL, OF TIFFIN, OHIO.

GRADING OR SCREENING APPARATUS.

Application filedfDeeei-nber 18, 1916.

To all eli/tom t may concern.'

Be it known that l, EUGENE E. LANDAr-IL, a citizen of the United States, residing at Tiiiin, county of Seneca, and State of Ohio, have invented certain new and useful Improvements in Grading or Screening Apparatus; and do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

llhis invention relates to grading or screening apparatus; and while the principles of the invention are applicable broadly to apparatus for grading, screening or asserting articles and materials generally, the invention has to do more particularly with apparatus for screening coal.

Coal as it comes from the mine is in lumps of various sizes admiXed with a considerable quantity of slack or fines. It is necessary to grade this run of mine coal into the various commercial sizes, such as nut, egg, and lump, and to separate from the salable coal the slack which is practically worthless except for special purposes. It is also necessary to pick out from the coal fragments of slate and the like which have no combustible value and which generally accompany the good coal as it comes from the mine.

lt is a principal object of the present invention to provide apparatus for accomplishing the foregoing operations in a thorough, complete, and systematic manner, while at the same time largely preventing the formation of additional quantities of lines or slack by guarding against unnecessary rough handling and consequent breakage of the coal during the grading or screening operations. 1t is also an object of the invention to provide apparatus of simple, rugged and compact construction which is relatively inexpensive in iirst cost and is economical in subsequent operation and upkeep. i

Broadly speaking, the improved apparatus is characterized by a screening or grading surface made up of ropes or cables extending longitudinally in parallel spaced arrangement. rlhe cables or ropes are supported on a series of rotary members, most desirably in the form of grooved cylinders Specification of Letters Patent.

Patented July 3, i917.,

Serial No. 137,828.

or drums, mounted to revolve on axes eX.- tending transversely of the cable strands; and the cable is so trained or reeved around these several rotary members that the screening surface is divided into a. number of successive sections, the width of the spaces between the strands in any particular section being uniform for that section, but diering from the corresponding spaces in the sections immediately preceding and following. At the same time the successive sections merge directly into each other, substantially without any break or interval between sections, thus affording a smoothly continuous and unobstructed screening and forwarding surface from one end of the apparatus to the other. This result can be attained in various ways, but in practice it is desirable to form the screening surface of a plurality of endless rope or cable units, the rope of each unit being reeved around the rotary supporting members in pairs, the first rotary memberof the series always constituting one member of the pair. ln this way the width of the screen apertures may be made to increase with each succeeding section in a` methodical manner, as will be more fully hereinafter explained. As many of these endless rope units are employed as may be necessary to give the desired total width of screen surface.

Having in mind the foregoing brief outline of the invention and the general purposes in view, a practical embodiment of the principles of the invention will now be described in detail and further advantages realized in the improved construction will be pointed out, it being understood, however, that the particular construction here illustrated serves merely as an explanatory example of apparatus within the scope of the broad invention, and that various changes in mechanical details and arrangement may be made without departure from the broad invention. The apparatus illustrated in the accompanying drawings is adapted more particularly for use in screening and grading coal. In these drawings Figures l and la, joined end to end, illustrate the apparatus in side elevation, portions being broken away and in section, and the view being divided in order to permit illustration on a larger scale than would otherwise be possible;

Fig. 2 is an end view of Fig. l from the left, on a larger scale than Fig. l;

Fig. 3 is a 'section on the line 3-3 of Fig. l, also on a larger scale than Fig. 1';

Fig. 4 is a plan view, more or less diagrammatic and on a reduced scale, illustrating the method of reeving the screen cables;

Fig. 5 is a fragmentary view similar to Fig. t but on a larger scale, showing how one of the cable units is reeved around its rotary supports;

Fig. 6 is a detail, partly in section, of the driving sheave member or rotary cable support;

Figs. 7, 8 and 9 are similar views of other sheave members or rotary supports;

Fig. 10 is a side elevation of half of one of the sheaves of Figs. 7, 8 and 9;

Fig. 1l is a detail and side elevation of one of the rotary agitating members.;

Fig. 12 is a side elevation showing one method of mounting and driving the rotary agitators.

Referring to the drawings, 20 indicates timber supports which may be similar to those commonly employed in coal tipple construction, and 2l designates generally a steel framework which serves to carry the operating parts` proper of the apparatus. Transversely journaled in this framework are a series of rotatably grooved cylinders or sheave members indicated generally by A, B, C and D, respectively, the axes of said members being substantially horizontal and parallel as shown. These cylinders or drums are mounted at suitable intervals along the framework to provide for successive screen sections, three sections in this instance; but it is to be understood that the number of cylinders may be greater or less than four with a corresponding variation in the number of screen sections. For reasons to be eX- plained later, the several sheave members are most desirably journaled at different levels, the first or driving sheave member A being the lowest, and sheave member C the highest; while sheave members B and D are at a slightly lower level than C.

In the specific example here shown, the screen surface is made up of four endless rope or cable units, the cable of each unit being wrapped or reeved around all of the four sheave cylinders A, B, C and D, and maintained in proper tension thereon, in a manner now to be described. Referring more particularly to Figs. 2, l and 5, and starting at the point marked 22, (Fig. 2) it will be seen that after leaving the obliquely disposed tension sheave 23, the'endless cable of the irst unit is led over sheave drums A, B and C to drum D, passes around and under D back to A; then forward again to B,

around and under B back to A; forward tension sheaves 23, 23b and 23.

over B and C, around and under C back to A; forward again to B, around and under B back to A; then forward again over B and C to D, and so on, and finally around and under D back over an idler sheave 24 journaled on the supporting frame, as shown, alt a point somewhat below and in advance of cylinder A. The cable after passing over this idler sheave goes down around the oblique tension sheave 28 and then up back to the starting point at 22, thus completing its cycle. The other cable units of the screen surface, three in this case, are reeved around the sheave members A, B, C and D in a manner similar to that j ust described, said units being provided, respectively, with idlers 24a, 24h and240, and Each of the tensionV sheaves is provided with a heavy counterweight 25 suspended therefrom and conveniently guided for vertical movement by uprights 26. It will be noted that in the particular arrangement here shown, the cable of the second unit passing upwardly from tension sheave 23L engages on the up- .per periphery of drum A the same groove engaged by the last strand of the first unit on the. underside of said drum, the relative arrangement of the tension sheaves23a and the idler sheave 24: being such as to permit this without the cable strands interfering. The same arrangement is of course provided for the succeeding units.

From the foregoing description of the cable reeving, it is apparent that in that section of the screen surface defined by the sheaves A and B, all the upper cable laps are present; that in the section between sheaves B and C, only half as many are present; and that in the third section, between C and D, only one fourth as many laps are present as in the first section. The screen apertures thus become larger in each succeeding section; and as the several sheaves are so grooved as to render the cable laps substantially parallel, the width of all the screen apertures in any one section is of course substantially the same. The variation in the number of cable laps in the succeeding sections of the series, as well as the variation in the width of the screen apertures in the succeeding sections, evidently follows a geometric progression.

Suitable means are provided for driving one or more of the drums or cylinders to adi 6 to 9 inclusive. Sheave members A (Fig.

6) and B (Fig. 7) have their grooves spaced apart the same distance, that is, the minimum distance, since all the upper cable laps are trained on sheaves A and B. On sheave member C (Fig. 8) the grooves may be twice as far apart since this sheave member is engaged by only half the total number of cable laps. Similarly the grooves on sheave member D (Fig. 9) may be four times as far apart as the grooves on A and B. The driving sheave member A is here shown constructed as an integral drum. Sheave members B, C and D may be similarly constructed but in some cases it is more desirable to build them in separate sheave sections or units as illustrated in Figs. 7, 8 and 9, and to mount the sections of each sheave member loosely on a supporting drum 29, which latter is secured to a rotatable shaft 30. The sheave sections being angularly movable on the drum 29 with respect to each other, any slack in the cable laps can be readily7 taken up and distributed by the tension devices before described. This sectional sheave construction can of course be varied in its details, but the arrangements illustrated in Figs. 7, 8 and 9 are useful in practice. Thus in Fig. 7, sheave section 31 is suitable for the end or outside she-ave sections on sheave member B, 32 being typical of the intermediate or inside sheave sections. Similarly 33 (Fig. 8) represents an outside or end sheave section of C and 34 one of the intermediate sections. In Fig. 9, 35 is one of the end sections of sheave member D, while 36 are intermediate sections. Tt will be understood that Figs. 6 to 9 illustrate only small portions of the complete sheave members A, B, C and D.

By locating the series of sheave members out of straight alinement and in such manner that the periphery of either intermediate sheave member, B or C, projects above the straight line tangent to the upper peripheries of the sheave members between which it is situated, and by providing tensioning mechanism as hereinbefore described, positive engagement of the upper cable laps with the grooves on the sheave members is insured. This is of great practical importance in view of the necessity for maintaining constant at all times the different widths of screen apertures in the several screen sections. Unless this is done, accurate grading of the coal or other material treated is impossible. As a further aid in this direction, it is desirable to provide grooved idler rolls 87 and 37a rotatably mounted in suitable bearings in the side plates 3S of the apparatus framework, several of these grooved idlers being best employed for each screen section, and the upper cable laps being trained thereover and guided in the grooves thereon. Most advantageously, these rolls project somewhat above a line tangent to the sheave cylinders between which they are situated, which causes the cable strands to engage said rolls positively. Tt will be seen that the described arrangement of sheave members and grooved idler rolls gives the upper screen surface of the cable strands a generally convex contour lengthwise. This arrangement greatly enhances the accuracy of the screen apertures and lateral rigidity of the cable laps forming the several screen sections, especially where steel wire cable is employed, as is most desirable in the type of apparatus here shown.

Tn order to secure a certain amount of agitation and stirring of the coal as it is carried forward upon the successive screen sections, it is desirable to provide, at least in the first two sections, agitators arranged to work between certain of the cable laps and to lift the material from the screen and turn it over during its travel so as to dislodge from the lumps such slack and dust as might. otherwise escape removal. In the present example such agitators comprise fingers or arms 39 carried on rotary disks or spiders 40, which latter are adapted to be secured to shafts el of the grooved idler rolls 3TH, said idler rolls beine' constructed in sections between which the agitator members may be placed. Special means may be provided for driving the rolls 3" carrying the agitator members; but as a rule the frictional engagement of the cable laps with these grooved rolls is suliicient to insure effective operation of the agitators, which of course rotate in a clockwise direction as here shown. Tn order, however, to prevent undue breakage of the coal lumps by reason of a tendency to slide or drop sharply from the agitator or lifting arms 89, when these arms are approaching and passing through their vertical positions, the forward or working edges of said arms are shouldered or notched as at a2 to provide for temporary retention of the elevated lumps, or at least to retard and check their descent to the screen.

Tn addition to favoring positive engagement of the cable laps with the rotary sheave members, the arrangement of the sheave members here illustrated provides for a gentle upward slope of the i'irst screen section in which the apertures are of minimum width. lt is at this stage of the screening operation that practically all the slack and lines should be separated from the coal; and the upward slope of this section is important in this connection because it temporarily retards the forward movement of the coal to some extent; and in conjunction with the rotary agitators, it favors a very complete dislodgment and separation of the slack. At the next screen section, between B and C, which is more nearly horizontal, opportunity is given attendants stationed on both sides of the apparatus to pick out slate, the rotary agitators provided for this section being useful particularly to stir up the mass of coal and expose the slate fragments.

Coal may be fed to the screening apparatus from a feed hopper 43 located above the main driving sheave cylinder A, the coal being retained in position on the screen surface by appropriate means such as side plates 44. Provision is also made for receiving material passing through the several scieeii sections and conducting it to separate places of discharge. The slack and fines from the rst screen section drop through a slack hopper and chute 45 and are discharged thence into a receiving car, for example. The hopper bin 46 extending under the greater part of the apparatus catches any fine material which may be carried along by the cable strands and dislodged therefrom during their return travel below the screen surface back to the main driving sheave member. Conveyer screw 47 may be provided in the bottom of this bin for convenient removal of material therefrom. Nut coal and egg coal are discharged through laterally extending hopper cliutes 48 and 49, respectively, these chutes being conveniently provided with lip screens 50 through which any small amount of dust and slack still retained by the lumps may be discharged to the slack bin 46. Lump coal too large to pass through the apertures of the last screen section is discharged from the apparatus at 51.

The mode of operation of the apparatus is sufficiently clear from the foregoing description, but will be biiefly summarized. The first sheave member A is driven as described to advance the screen surface, and coal passes from feed hopper 43 to the first screen section where it is moved forwardly and upwardly by the advancing screen surface and is at the saine time agitated and to some extent moved forward by the rotary agitator devices. These latter, operating in the spaces between the cable strands, lift lumps of coal and turn them through substantially 90 degrees, but at the same time prevent the lumps from falling sharply tothe screen surface. During its passage over the first screen section the coal is largely freed of the accompanying slack, and the comparatively clean coal then passes to the second screen section where it is further stirred by rotary agitators, slate fragments being picked out by attendants, and coal of nut size screened out and conducted away. The coal which still remains on the screen then passes to the third section where egg size is screened out, the large lumps still remaining on the screen then passing off at 51. It is to be especially noted that throughout its travel the coal has .been advanced in a smooth and continuous manner, its passage from one section to the next succeeding section being devoid of drop or j ar. This characteristic of the apparatus n is important in that it minimizes breakage of the coal lumps and formation of nes, an important factor in the practical handling of coal.

It is obvious that various changes can be made in the details of the apparatus without departure from the broad invention disclosed herein and defined in the appended claims.

What I claim is:

1. Grading or screening apparatus comprising, in combination, a plurality of rotary members supported on substantially parallel axes, said axes being spaced apart distances corresponding to the desired extent of screen sections, cable reeved around all said members in such manner that the upper cable laps form a continuous screen surface from the first axis to the last axis, the cable laps being spaced farther apart in each succeeding screen section, and means for receiving material passed through each screen section.

2. Grading or screening apparatus comprising, in combination, a plurality of rotary members supported on substantially parallel axes, said axes being spaced apart distances corresponding to the desired extent of screen sections, cable reeved around all said members in such manner that the upper cable laps form a continuous screen surface from the first axis to the last axis, the cable laps being spaced farther apart in each succeeding screen section, means for advancing the cable laps in the saine. direction, and means for receiving material passed through each screen section.

3. Grading or screening apparatus comprising, in combination, a plurality of sheave members supported for rotation on substantially parallel axes defining screen sections, cable reeved around said sheave members in pairs to form a continuous screen surface, the sheave member at one end of the series always being one-member of the pair, and the reeving being carried out in such manner that the screen apertures are substantially uniform in size in any given section, but increase in size in successive sections, means for driving the sheave members, and means for receiving material from the several screen sections.

4. Grading or screening apparatus comprising, in combination. a supporting framework, a series of rotary sheave members mounted transversely on said framework and suitably spaced apart, cable reeved around the first sheave member of the series and each one of the succeeding sheave members, in pairs, in such manner that the upper cable laps form a continuous screen surface from one end of the series to the other, the

Vreeving being such that the screen apertures are smallest between the first and second sheave members and increase in size between each succeeding pair of sheave members, means for advancing the screen surface, and means for receiving material from each screen section.

5. Grading or screening apparatus comprising, in combination, a supporting framework, a series of rotary sheave members mounted transversely on said framework and suitably spaced apart, and cable reeved around the several sheave members in pairs to form a continuous screen surface extending over the entire series, the reeving being such that the apertures in any one section of the screen between a pair of successive sheave members are substantially uniform in width, while said apertures differ in width for dierent screen sections, varying substantially in accordance with a geometrical progression.

6. Grading and screening apparatus comprising, in combination, a series of sheave members supported for rotation on axes which are substantially parallel and suitably spaced apart, an endless screen surface extending continuously over the whole series and formed by the upper laps of a plurality of endless cable units, each unit consisting of a cable reeved around all of said `sheave members, the arrangement being such that for any screen section between a pair of successive sheave members the screen apertures are substantially of uniform width, but are substantially twice as wide as the apertures in the section next preceding.

7. Grading` or screening apparatus comprising a continuous unobstructed traveling forwarding and "screening surface having closely-spaced, parallel, longitudinal, screen apertures, said surface being' composed of successive sections merging into each other without break in continuity, the apertures in any given section being all of substantially equal width but wider than those in the next preceding section.

8. Grading or screening apparatus comprising a continuous unobstructed traveling forwarding and screening surfacev having closely-spaced, parallel, longitudinal, screen apertures, said surface being composed of successive sections merging into each other without break in continuity, the apertures in any given section being all of substantially equal width but wider than those in the next preceding section, in combination with means for receiving material from the several screen sections.

9. Grading or screening apparatus comprising a series of transversely disposed elongated rotary members, and cable trained around said members, the upper laps of said cable forming a continuous screen surface,

all said upper laps starting from the first rotary member of said series but extending to and terminating at different succeeding members of the series, in such manner as to form successive screen sections of increasingly wide screen apertures, in combination with means for drivingone of said rotary members to advance the screen surface.

10. Grading or screening apparatus comprising, in combination, a plurality of rotary supports, a screen surface composed of a plurality of screen sections formed by spaced parallel upper laps of cable trained around said supports, the spacing being different for the different sections and increasing from the first to the last section, the first screen section being inclined upwardly from a point of feed, and driving means for advancing the screen surface.

ll. 1n grading or screening apparatus, a screen surface composed of spaced parallel strands of endless cable and inclined upwardly from a point of feed to a point of discharge, means for advancing said strands in the direction of discharge, and agitator means operating between said strands to lift material therefrom and to aid in advancing it.

l2. Grading or screening apparatus comprising, in combination, a traveling screen surface composed of cable strands in spaced parallel arrangement, agitator members arranged to work between pairs of said cable strands, said agitator members comprising lifting arms or fingers having their working edges shouldered or notched in a manner tending to prevent sudden dropping of material lifted thereby while permitting free release of said material at the screen surface.

13. Grading or screeningapparatus coniprising a continuous unobstructed traveling forwarding and screening surface having closely-spaced, parallel, longitudinal, screen apertures, said surface being composed of successive sections merging into each other without break in continuity, the apertures in. any given section being all of substantially equal width but wider than those in the next preceding section, in combination with means operating in certain of the screen apertures to agitate material on the screening surface.

lll. Grading or screening apparatus com? prising a series of tranverse grooved supporting cylinders suitably spaced apart in parallel arrangement, cable trained around said cylinders to form a screen surface, tensioning means for maintaining said cable taut, transverse grooved spacing or guiding rollers intermediate said cylinders and engaged by the cable strands, and agitator fingers mounted on said rollers and arranged to enter between said. strands as the rollers turn.

15. Grading or screening apparatus comprising a series of transverse grooved supporting cylinders suitably spaced apart in parallel arrangement, cable trained around said cylinders to form a screen surface of parallel cable strands, tensioning means for maintaining said cable taut, and transverse grooved spacing or guide rollers intermediate said cylinders and engaged by the cable strands, said cylinders and rollers being so mounted relatively to each other as to give a screen surface of generally convex contour lengthwise.

16. Grading or screening apparatus comprising a series of grooved cylindrical supporting` members mounted to rotate on substantially parallel axes which are suitably spaced apart and so located relatively to each other that the periphery of any intermediate member projects above the straight line tangent to the upper peripheries of the two members next adjacent such intermediate member, and cable trained around said members to form a screen surface of parallel strands, in combination with tensioning means for keeping the cable taut and in positive engagement with the grooves on said members, and driving means Afor advancing said screen surface.

17. Grading and screening apparatus comprising rotary sheave members, cable trained around said sheave members to form a longitudinally movable screen surface, driving means for advancing the screen surface, and tension means for maintaining the cable taut, at least one of said rotary sheave members being constructed of sections which are angularly movable with respect to each other about the rotation axis of said member.

18. Grading or screening apparatus comprising, in combination, a plurality of rotary members supported on substantially parallel axes, said axes being spaced apart distances corresponding to the desired extent of screen sections, cable reeved around all said members in such manner that the Y upper cable laps form a continuous screen surface from the first axis to the last axis, the cable laps being spaced farther apart in each succeeding screen section, means engaging the upper cable laps betweenpeach pair of rotary members to insure accurate spacing of said laps, `and means for receiv-` ing material passed through each screen section.

19. Grading or screening apparatus comprising a series of parallel transverse grooved supporting cylinders suitablyl spaced apart, wire cable trained around said cylinders in such manner that the upper cable laps form a continuous unobstructed screening and forwarding surface having successive sections of different sized screen apertures, tensioning means for said cables, and grooved guide rolls intermediate said cylinders, said rolls engaging the upper' cable laps and maintaining them in accurate spaced relation.`

20. Grading or screening apparatus comprisingV a V'series of parallel transverse grooved supporting cylinders suitably spaced apart, wire cable trained around said cylinders in such manner that the upper cable laps form a continuous unobstructed screening and forwarding surface having successive sections ofvdifferent sized screen apertures, tensioning means for said cables,

grooved rolls intermediate said cylinders,A

said rolls engaging'the upper cable laps and maintaining them in accurate spaced relation, and fingers or arms carried by saidrolls and arranged to enter between the upper cable laps as the rolls rotate.

21. In grading or screening apparatus, a continuous unobstructed screening and forwarding surface comprising substantially parallel laps of endless cable so arranged as to form successive screen sections havingl `elongated screen apertures of diiierent widths, but all the apertures of any given section being of substantially the same width, and meansfor advancing the cable laps in the same direction.

22. VIn grading or screening apparatus, a plurality of parallel transverse rotary supports, in combination with a single endless cable reeved around all of said supports Ain such manner that' the upper cable laps are parallel and form a continuous unobstruct` ed screen unit comprising successive sections, the screen apertures in any given section all being of substantially the same width, but diifering in width from the apertures in adjacent sections.

signature.

EUGENE E. LANDAHL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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