US2080977A - Mechanism for screening and transferring coal and the like - Google Patents

Description

May 18 1937. 2,080,977

MECHANISM FOR SCREEN ING AND TRANSFERRING COAL AND THE LIKE J. A. ALBRECHT Filed March 6, 1955 4 Shets-She et} I Eva-W912 2; O Wm J. A. ALBRECHT 2,080,977

May 18, 1937,

MECHANISM FOR SCREENING AND TRANSFERRING COAL AND THE LIKE 4 Sheets-Sheet '-Filed March 6, 1933 Q I dINVENTOR BY o m ATTORNEYS May 18, 19 37.

.1. A. ALBRECHT Filed March 6, 1933 4 Sheets-Sheet 3 l ATTORNEYS 4 Sheets-Sheet 4 VII/IIII/IllI/IIII INVEZTEZ;

BY v

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JIATTORNEYS J. A. ALBRECHT FiledJ March a, 1953 MECHANISM FOR SCREENING AND TRANSFERRING COAL AND THE LIKE May 18, 1937.

Patented May 18, 1937 MECHANISM FOR SCREENING AND TRANS- FERRING COAL AND THE LIKE Joseph A. Albrecht, Buffalo, N. Y., assignor to Bettinger Coal & Coke Corp, Buffalo, N. Y., a corporation of New York Application March 6, 1933, Serial No. 659,728

4 Claims.

This invention relates to a mechanism for conveying or transferring loose material from one point to another and, at the same time, screening said loose material while in transit,-and relates more particularly to a mechanism for discharging loose, lump material, such as coal, from a storage bin or silo and loading the same into a truck.

The principal object of the invention is to discharge the coal or other loose material at a high, constant rate of speed, with a minimum of coal breakage, and with the coal so screened as to be of uniform size and entirely free of coal dust fines (coal breeze). Numerous other objects of the invention and practical solutions thereof are disclosed in detail in the herein patent specification, wherein:

In the accompanying drawings:

Fig. 1 is a fragmentary, vertical, longitudinal section through a coal storage silo provided with one form of my improved screening and transferring mechanism.

Fig. 2 is a fragmentary, vertical section thereof taken on line 22, Fig. 1.

Fig. 3 is a diminutive, vertical section showing a modification of the invention with the screening and transferring mechanism located partially within the silo.

Fig. 4 is a diminutive, vertical section showing another modification of the invention with only the stationary shelf located within the silo.

Fig. 5 is a diminutive, vertical section showing the invention applied to a silo in which the opening thereof is considerably above the screening and loading mechanism.

Fig. 6 is a diminutive, vertical section of a simple form of the invention provided with a one-piece discharge boot.

Fig. 7 is a diminutive front elevation (with parts broken away) of another modified form of the invention in which two screening and transferring mechanisms are fed by a single silo opening.

Fig. 8 is a schematic horizontal section of another modified form of the invention similar to that of Fig. 7 but showing threeinstead of two screening and transferring mechanisms fed by a single, silo, side opening.

Fig. 9 is a schematic horizontal section of another modified form of the invention showing two pairs of screening and transferring mechanisms fed by a. single central opening in the bottom of the silo.

Fig. 10 is a fragmentary vertical section showing means for cutting off the flow of loose material at a point above the sizing screen.

Fig. 11 is a similar fragmentary, vertical section but showing a somewhat modified means of effecting the same result, namely to enable the flow of loose material to be out off at the outer edge of the adjustable shelf.

Fig. 12 is a fragmentary vertical section showing a construction similar in general to that of Fig. 11 but with the upper end of the sizing screen disposed somewhat closer to the silo.

Fig. 13 is a fragmentary frontelevation of a silo equipped with my invention and provided with a form of discharge boot which enables the operator to distribute the loose material evenly in the truck or other Vehicle body.

Similar characters of reference indicate like parts in'the several figures of the drawings.

My invention may be embodied in various forms and in screening and loading mechanisms of different constructions, and the presentapplications are therefore to be regarded merely as a few of the organizations which satisfactorily carry out the invention in practice. here shown, and referring for the present toonly Figs. 1 and 2, the same is'constructed as followsz The numeral It] indicates anordinary vertical bin or silo in which coal (or other loose, lump material) is stored, and from which the coalis adapted to be discharged into a truck H or other conveyance. I

The problem which has been solved by the present invention is to load the truck in the shortest possible space of time with clean and uniformly sized coal loaded in an evenbed in said truck and without breaking the coal during the loading operation. In general, these results are obtained by causing the coal to flow at a high but constant speed over the sizing screen l2 and thence to exact desired portion 4 out of the silo through a large, rectangular opening l4 formed in the front wall of said silo. In the present invention, this opening I4 is of sufficiently large size to prevent any archingor bridging of coal across said opening, and hence also sufiiciently large to prevent any stoppage of coal flow as a consequence of said arching.

In explanation of this tendency of the coal to arch, it should be stated at the outset that the size of opening in which any certain loose material is apt to arch depends upon the kind and size of the material passing through or attempting to pass through said opening. In the case of anthracite coal, for instance, it has been found that anthracite coal of chestnut size is apt to arch-many opening 12" or less inwidth; stove coal in any opening 14" or less in width;-

and egg coal in any opening 16" or less in width,

etc. In the actual practice of the presentinvention, the opening M for coal silosis made about 24" in width so as to provide an ample factor of safety against any possibility of arching.

The coal passing throughsaid opening "i4 flows down upon a horizontal, stationary shelf [5 which is preferably overlaitlionrits .upper surface with a protective sheet of iron l6. tionary shelf is secured in any suitable 'manner tozthe walls'of the silo 10, andmerges atits-inner end into the lower edge of-the inclined false, silo bottom it aforementioned. Secured to said sil at'opposite longitudinal sides of and just below theistationar ycshelf 'lfi thereof is a pair of guide rails 7" which are constructed .in any suitable manner, for instance (as shownzin the'di'awings) by :ben'dingihorizontally inward the lower edges of a pair of vertical, longitudinal, sheet-metal, sidewalls [:8 whichaare secured to the side faces of the opening Id-and have the function of preventing coal from spilling oii the side of the shelf *5.

hn-anged to slide longitudinally in these guide rails =11isan adjustableshelf Ha which, similar 1y to the stationary shelf I5, is preferably protected-omits uppenhorizontal surface with a sheet of iron ll. Secured'to and-projectingdownwardly from said adjustable shelf 45a is a lug 2B which -is provided with an -internally threaded hole to receive the externally threaded shank of 'a longitudinal, horizontal adjusting screw 21. The latter is 'rotatably journalled in a bracket 22 which is secured by stud screws -23to the "outer front-face of the silo. Suitable annular shoulders are formed-onsaidadjusting screw 2i so as to prevent "longitudinal movement thereof relatively 'tot'he bracket 22 "in which it is 'journaled. 'The'ou'ter end of said screw is provided with a squared head or is "otherwise suitably arranged to permit of its being readily rotated in the one 'or'other-direction.

Attention is directed to the imaginary line 2% *whichrepresents the angle-of-rep'ose line of the 'c oarwh'ichflows out of the silothr'ough its opening II. "This angle-of-reposeline is substantially constant for any certain size and -kind of coal or other loose material and represents the upper boundary of the body of loose 'coalwhich'isrestingupon the stationary and adjustable shelves "i5 and Ilia-either when the coal is "flowing or is static.

It will'be noticed that the front transverse edge of the adjustable shelf 15a is situated some distance 'rearwardly of the adjacent part of said angle-of-reposeline 24. This means that, in the .position of tire-parts as shown in the drawings, the coal is being allowed to flow over -the front, transverse "edge o'fsaid adjustable shelf 15a. The amount of the "flow is substantially constant for any certain size and kind of coal or other loose material and for any certain longitudinal position of the adjustable shelf 'li5'a. This is due to the fact that the coal at all times tries to maintainaposition 'onsai'd shelves i5 and 15a corre- This staspending to its angle-of-repose line 24. Hence as fast as the coal falls over the front edge of the adjustable shelf [5a, it is replaced by an equal amount of coal flowing from the silo I0 through the silo opening l4 and onto said shelves I5 and [5a. In other words, the rate of flow of the coal over the outer edge of the adjustable shelf l5a is uniform because of the fact that the angleof-repose line 24 is constant, and is, in addition, uninterrupted because the size of the opening I4 is'too large to permit of any accidental arching 'of the coalflatssaidopening.

The rate of now of the coal over the front edge of said adjustable shelf I5a depends upon the distance of said front edge from the angle-ofrepose line 2%. Hence, by providing means for longitudinally moving said adjustable shelf l5a. -either inwardly or outwardly as may be desired), the rate of flow of the coal may be adjusted'to most efiiciently suit the particular characteristics of the coal 'beingdischarged from the silo as regards both the rate at which the 'truck is loaded and also -the freedom from dust or fines of the coal delivered to said truck.

'Theifront edge of said :adjustable-s'helf 15a is vpivotally connected by a hinge 25 with the 'upper end of the downwardly :and forwardly inclined sizing screen l2, the same being constructed either of -a'plurality of longitudinal screen bars 26,.as shown in Figs. 1, -2, a, s, and 9 or or wire mesh, as shown in Figs. 3- 6. 'This'sizing screen I2 'is not necessarily thus hinged to said shelf but may vbeentirelyseparate therefromor other- :wisearranged in any suitable manner. -Said sizing screen tz'is so constructed as to allow any certain size of coal to fall through its openings and, if desired, it may -be made in a series of screens having progressively larger sized openings so as to segregate or screen the coal into a plurality "of sizes. The particular sizing screens illustrated in the h'erein "patent application are used merely to size the coal to the extent of screening out the coal fines (coal breeze and coal screenings), which latter fall through said screens and are collected in a storage compart- Trient -21from which they may be periodically removed by manually raising a vertically slidable door 28 which is arranged at the extreme lower end of '"said compartment.

The screening of either coal or of any other loose material can only be properly effected if the stream of loose material moving upon said screen isimaintain'ed at or below *a certain'definite depth. For instance, ordinary, anthracite, chestnut coal flowing over a screen must have a 'thickness of not over 3%" if said "chestnut coal is to be entirely-relieved of its coal fines. For stove coal the stream should be '5 or less thick,for :egg :coal 6 1 etc. In other words, the larger the size of the lumps of coal, the thicker the optimum depth of 'the coal istream flowing over :its sizing screen l2, the optimum depth being that depth which will provide the maximum loadingnrate and will, at the same time, enable the objectionable .fines or screenings to be completely removed from the coal. (There are, of course, other factors involved in this question, such as the length, shape and slope of the screen and whether or not it is vibrated, etc. but no useful purpose is to be obtained by discussing such questionshere.)

From these considerations it follows that, to discharge a quantity of clean coal from a silo or other bin at the highest rate of speed, it is necessary'that the flow of coal over the sizing screen 12 be substantially constant and of a certain definite amount per unit of time. This is so because, if the layer of coal which is flowing over said sizing screen drops in thickness below its allowable optimum (for instance 3 then the rate of discharge of the coal is lowered;whereas, if the thickness of the layer of coal flowing over said sizing screen is too thick, then the result is a dirty and improperly screened product. It is because of this desirability of an uninterrupted, even rate of flow of the coal or other loose material that renders great value to the arrangement of the shelf I51; and the opening l4, whereby such a flow is obtained.

It has been found desirable to have said siz ing screen i2 arranged at an angle somewhat smaller (flatter) than that of the angle-of-repose line 24. This is due both to the fact that the loose material which flows down upon said sizing screen has an initial velocity as it starts its travel over said screen, and also to the fact that the angle of repose of said loose material, when lying upon said sizing screen, is less than the angle of repose when lying upon itself (i. e. upon the adjustable and stationary shelves I5,,l5a). Exactly what the angle of said screen l2 and consequently what the angle of its flow line 29 ought to be for maximum efliciency depends upon the size and kind of the coal or other loose material being handled. To properly take care of whatever particular kind of coal happens at the time to be stored in the silo, said sizing screen is rendered angularly adjustable by the provision of a row of adjustment holes 30 formed in the opposite side walls of the coal dust storage compartment 2'1. Engageable with any desired horizontally-disposed pair of said holes 30 is a supporting, adjustment bar 3! upon which rest the longitudinal depending skirts $2 of the sizing screen I2. Said skirts ensure that the coal dust falling through said sizing screen l2 will fall without any leakage into the dust storage compartment 21 irrespective of which pair of adjustment holes 38 is supporting the adjustment bar 3!. Said sizing screen I2 is also provided with a pair of upstanding, longitudinal, sheet metal flanges 33 which prevent the descending stream of coal (sliding down on the upper surface of the sizing screen l2) from spilling off the side of said sizing screen.

Pivoted at St on the front, upper part of said upstanding flanges 33 is a bail to the upper, central part of which is secured a flexible cable 36. The latter passes vertically upward and around a suitably grooved pulley or sheave 31 and is connected at its opposite end to a counterweight 38. Said sheave is suitably journaled in a bearing ii! secured to the outer end of a bracket 41 which is arranged on, and suitably braced to, the silo l0. By reason of this counterweight 3B, the entire sizing screen i2, together with its skirts 32 and upstanding flanges 33, may be readily raised or lowered manually about the hinge 25 as a pivot. This permits the operator to cut off the flow of coal from the silo Hi without the employment of any of the coal flow gates which are ordinarily used for this purpose,said sizing screen I2 being merely raised until it is approximately horizontal, whereupon all flow of coal ceases.

When it is desired to again resume the coal screening and transferring operation, said sizing screen I2 is merely depressed until it rests upon the adjustment bar 3|. When said screen is in this position, the coal is caused to flow in an in Fig. 1) the same is held in this lower position by a bell crank latch 42 which (see Fig. 2) is centrally pivoted at 43 to one vertical side wall of the coal dust compartment. The nose of said latch is adapted to engage with the horizontal and outwardly projecting flange of a latch plate 44 which is secured by bolts 45' to one of the upstanding flanges 33 of the screen l2. As the latter descends, said latch 42 is caused to engage with the latch plate M of said screen by the provision of a suitable, arcuate or curved spring 46 which resiliently urges the latchin a counter-clockwise direction (as viewed in Fig. 2). Disengagement of said latch 42 (in the construction of Figs. 1 and 2 at present being described) is effected by a pull cord 49 which depends from the horizontal arm of said latch and has its lower end disposed within convenient reach of the operator who is ordinarily at this time stationed on or adjacent to the truck i l which is being loaded. Whenever the adjustment bar 3| is placed in a different pair of horizontally disposed adjustment holes 30, a corresponding change in the position of the latch plate 44 relatively to screen I2 is required. Such a change is effected by providing a pair of curvilinear rows of holes 4?, 4'ia,-each hole in each row being matched by a companion hole in the other row disposed horizontally with respect to said first named hole. Thus the bolts 45 may be placed in any desired pair of horizontal holes 4?, 41a and the latch plate 44 thereby located in a position suitably to engage with the latch 42 for any particular one of the positions of the adjustment bar 3|.

Projecting downwardly and forwardly from opposite sides of the sizing screen l2 are a pair of arms 48 to the extreme front ends of which is pivoted, at 50, the upper end of an upper boot section 5|. The upper part 'of said upper boot section is of funnel shape so as to properly rew ceive and concentrate the stream of coal falling off of the sizing screen i2,said funnel portion consisting of the vertical, longitudinal side wings 52 (which embrace the upstanding flanges 33 of the sizing screen) and the inclined side walls -i 53 (which slide the coal toward the axis of the upper boot section and avoid the necessity of constructing the latter of undue width).

The lower rectangular portion of said upper boot section 5| is, at its lower end, peripherally flanged outwardly and is received within the bore of a lower boot section 54. The upper edge of the latter is inwardly flanged so as to both prevent the same from moving downwardly below the position of Fig. 1, and also to reduce the area of frictional contact between the upper and lower boot sections 5i and 5t.

Said lower boot section 54 is adapted to move vertically (either up or down) relatively to the upper boot section 5!. To enable this to be accomplished without undue manual effort in either direction. said lower boot section 54 is counterweight supported upon said upper boot section 5i,a pair of suitable cords or cables 55 being secured at their lower ends to said lower boot section 54 and extending up and over a pair of companion pulleys 56 journaled on said upper boot section 5!, the free ends of each cable 55 being provided with a companion counterweight 51.

The lower boot section 54. is provided at its expartition 58 which prevents the descending stream of coal from falling directly down through both of the boot sections and 54 and thence down into the body of the truck H. Instead, the descending stream of coal isv prevented from descending directly and is caused to be deflected laterally through a pair of rectangular discharge vents 65 which are formed in the vertical side walls of said lower boot section 54. The speed of coal flow through each of said discharge vents is regulated by a companion shutter 5| which is vertically slidable on the companion outer face of said lower boot section 541 and is provided with a suitable handle 62 to permit of its being conveniently raised or lowered by the operator. Whenever the operator desires to shut off the flow of coal from said lower boot section 54 he pushes down and thereby completely closes each of said shutters 6|. The amount to which he is able to open either of said shutters is, however, limited by an adjusting screw 63, which is suitably threaded in a flange 64 of the lower boot section and is adapted to bear with its lower end against the upper edge of its companion shutter 6| (as shown in the position of Fig. l) at which time said shutter is in itsextreme elevated position. This adjusting screw 63 is adapted to be turned up or down until the rate of discharge of the coal throughihe discharge vents 6|) is equal to or slightly less than equal to the rate at which the coal is fed into the upper boot section 5| from the sizing screen l2. When thus adjusted, a generous head of coal may be maintained in the upper boot section 5| at the same time that the coal is descending from the sizing screen 12 and passing down into and through said boot sections. This prevents the coal from freely falling any considerable height from the tail end of said sizing screen l2. The coal then descends at a slow rate of speed through the upper and then through the lower boot sections 5| and 54, and then is discharged with substantially no initial vertical velocity from the discharge vents 50 into the body of the truck The reason why the coal has substantially no vertical velocity as it emerges from said discharge vents B5 is because its direction of movement at this time has a relatively large horizontal component, which latter helps to spread the coal out over the truck body and also causes the descending lumps to strike more or less obliquely (and hence without fracturing) against the flow of the truck, and against the surface of the pile of coal which has piled up thereon. It is the vertical velocity component which is chief ly the cause of coal breakage and this arrangement whereby the coal is deflected horizontally, so as to partially convert what would otherwise be vertical movement into horizontal movement very considerably reduces coal breakage.

Operation When the truck arrives at the silo ID for its quota of screened, clean coal, the sizing screen It. is at this time held in its upper (and more or less horizontal) position by its counterweight 38, while the lower boot section 54 is held in its extreme upper position relatively to the upper boot section 5| by its counterweights 5?. The operator now pulls down the sizing screen I2 about its hinge 25 as a pivot until it rests upon the adjustment bar 3| and is automatically locked in this position by the latch 42 in the position of Fig. 1.

treme lower end with a horizontal or transverse The coal lying upon the stationary and the adjustment shelves l5 and |5a more or less definitely retains its upper surface at the angle-ofrepose line 24, but, at the same time, now starts to spill over the outer edge of the adjustment shelf |5a and to slide in an even and uninterrupted stream down the sizing screen l2. The thicknessof this moving layer is substantially constant for any certain setting of the adjustment shelf |5a and angle of the screen |2,-this featureof the invention being highly desirable in that it renders possible the loading of coal at the highest rate of speed consistent with the complete removal therefrom of the coal fines and screenings, which latter fall into the compartment 2'! and are periodically removed therefrom through a door 28.

At this time the lower boot section 54 is in its upper telescoped position relatively to the upper boot section 5|, with the shutters 6| of said lower boot section closed. Ordinarily at this time said upper boot section 5| would be more or less filled with coal from a previous coal loading operation, but for purposes of explanation, it will be assumed that there is no coal at this time in either of said boot sections 5|, 54.

As the coal now starts to flow into the lower boot section 54, it first piles upon the transverse partition 58 of said lower boot section, and then commences to fill the hollow interior of said lower boot section. This causes said lower boot section to be forced downwardly against the resistance of its counterweights 51, the coal continuing to fill up said lower boot section and, when this operation has been completed, then filling the upper boot section 5|. All of the parts are now in the position of Fig. l and the coal flow is as indicated by the dash lines 24, 29, etc. The speed of the coal flow out through the discharge vents 50 (the speed being adjustably regulated by the adjustment screws 63) is adapted at this time to be such that the level of coal in the upper boot section 5| is a small distance below the front or bottom end of the sizing screen |2 (as shown by the dash lines), thereby preventing the coal from freely falling a sufiicient distance at this point to cause breakage. If the flow through said boot sections 5| and 54 is too slow to take care of the coal being discharged from the sizing screen l2, the flow of coal over the sizing screen I2 is automatically stopped by being dammed back,-the angle of the line 29 being less than that of the angle-of-repose line 24. The coal when either sliding upon or resting upon said sizing screen is prevented from spilling off from said sizing screen by reason of the upstanding flanges 33 of said screen.

The quantity of coal ied per unit of time from the silo ill to the sizing screen I2 is regulated by the screw 2|, while the slope of the sizing screen i2 is adjusted by the position of the adjustment, supporting bar 3|.

As the bottom of the truck becomes filled with the clean (screened) coal, the lower boot section 54 may be pushed upwardly by the operator with the help of the counterweights 51. Finally when the coal has filled the truck with the desired quantity of coal, the operator closes the shutters 6| and pulls down the pull rod 49 (thereby tripping the latch 42) and pushes up the sizing screen l2 with the help of its counterweight 38. This causes all flow of coal from the silo H] to cease. All of the parts are now in their elevated position so as to properly clear the cab of the next arriving truck which latter is then supplied with the desired amount of clean coal in the same manner as just described, except that now the upper boot section BI is more or less filled with coal, with everything in readiness for the next arriving truck.

It is obvious that the present invention is applicable to the loading of a great variety of loose,

lump materials. In this connection it should be pointed out that the invention has four different and independently desirable characteristics:- A. It provides an even, uninterrupted flow of any solid lumpy material which is apt to arch, B. It provides for a uniform and thorough screening of such lump material at the highest rate of speed, C. It enables the material to be discharged from a low point of discharge into the very bottom of the body of a truck or other conveyance, and at the same time is so organized as to be easily pushed up out of the way so as to clear not only the sides of the truck body, but also the truck cab or any other objects which are above and in the path of portions of the loading mechanism at the time when the loading operation is being consummated.

In Fig. 3 is shown one modification of the invention, particularly suited to conditions where the truck must drive in as close as possible to the silo IIlI. To accomplish this result the stationary and adjustable shelves I5! and I5Ia and also the upper part of the sizing screen I2I are arranged within the silo. This construction, while it decreases somewhat the capacity of the silo, has the advantage that rain, snow or sleet are prevented from falling on the coal when the loading mechanism is not in use. In this construction, an opening I4! is artificially formed by the provision of an inclined deflecting wall 65 and a pair of side walls '69. This construction renders desirable a different means of shifting the adjustable shelf I5Ia,the lug ZIlI in this case being provided with a horizontal and outwardly projecting, adjustment rod 66, the handle 67 of which is adapted to be moved inwardly or outwardly by the operator so as to control the rate at which the coal passes out through the opening MI.

Fig. 4 shows a construction which may be considered as midway between that of Figs. 1 and 3. In this case only the stationary shelf I52 is located within the silo I02, it being provided with an inclined deflecting wall 652 similar to that shown in Fig. 3.

Fig. 5 shows a method of using the present invention in connection with an already existing silo I03 which has been previously provided with a spout opening 68 located a considerable distance above the ground. In this case said spout opening feeds the coal into a vertical conduit Iii which conveys the coal downwardly into an opening I43 at its lower end. The coal from this point is handled in substantially the same manner as that disclosed in the previously described constructions.

In Fig. 6 is shown a simplified form of the invention in which a simple, non-collapsible boot 5 is employed instead of the collapsible boot 54, 5| of Figs. 1-5. With this form of the invention there is apt to be a certain amount of coal breakage when this boot 544 is first being filled, but it is to be remembered that the force of momentum of freely falling coal is proportional to the square root of the height which it falls, and that, therefore, the transverse partition 584, by breaking the fallof coal from the tailjof the sizing screen I24 to the floor of the occurring with the collapsible boots of Figs, 1-5.

When it is desired for any reason to use the sizing screen I24 without its non-collapsible boot 544, the latter may be thrown back about its pivot 564 into the position shown by dotted lines in the drawings.

In this construction of Fig. 6 is also shown a modified means of moving the adjustable shelf ltd-a, the opposite sides of which are provided with a pair of downwardly facing, longitudinal racks l I. Each of said racks is engaged by a companion gear I2 which is secured to a common, horizontal, transverse shaft 13. The latter is suitably jcurnaled on the silo I04 (or upon the walls of its coal breeze storage chamber 214) and is conveniently rotated manually by the provision of a hand wheel II -l at one of its outboard ends. Such a construction has the advantage that the adjustable shelf is positively restrained against any cocking tendency, i. e., tendency to twist out of alignment.

In Fig. 7 is shown a pair of sizing screens and telescoping boots fed from a single silo opening 685, thus permitting a pair of trucks tobe loaded simultaneously from a single silo opening. The organization in general of the screens, telescope boots 5|, 54, etc. is substantially the same as that shown in Fig. 1, except that said single silo opening 685 feeds the loose material to a pair of openings hi5 disposed at to each other. This arrangement furthermore permits of so placing the shelf adjusting screws 2I5, that they are very accessible, being disposed in the open space intermediate of the screenings storage compartments 215, which in this case are drained through a common discharge spout I5. This construction has the further advantage (similar to that of Fig. 3) that the trucks can drive in close to: the silo without interference from the screenings storage bins 215.

In Fig. 8 is shown a schematic representation of an arrangement whereby three sizing screens and their appurtenances are supplied with loose material from a single silo opening 686. Except for this feature, the arrangement of the parts is substantially like that of Fig. 7.

In Fig. 9 is shown a modified form of the invention in which four sizing screens with their 'ap-fl purtenances are fed from a single silo opening 681 located centrally in the bottom of the silo. Such an arrangement permits of the loading of four trucks simultaneously from a single silo opening.

Just exactly which form of the invention is preferable for any certain installation depends entirely upon the exact use to which that particular installation is to be put and the amount of capital expense which is warranted. For instance, where expensive and massive silos are already in place, the number of trucks, which can be loaded simultaneously, may have to be deemeda subordinate feature. If a number of silos are ar-v ranged in close juxtaposition, then it is impracti-' cable, for instance, to use the construction of Fig. 9, which is chiefly ofv value where the silos are. somewhat separated from each other. But thisv cuts down the overall storage capacity for a given. area, and that is the chief consideration in some layouts. Then again the factors involved may require (for maximum efficiency) a form or com-:. bined forms ofthe invention notshown at all in the accompanying illustrations; 'For instance,.

where aplurality of expensive silos in good condition and arranged close together and are already in situ, and where furthermore weather conditions call for a mechanism which is protected from snow and rain and still open for inspection, it may be desirable to have each silo (except possibly the end silos) provided with the central opening 68? of Fig. 9, but eliminating the necessity of one of the pairs of sizing screens with their appurtenances. It is obvious that numerous other such modifications may be made within the scope of the presentinvention and yet having an appearance considerably different from any of the layouts illustrated herein.

In Fig. 10 is shown a convenient means of shutting off the flow of coal without requiring any change in the position of the sizing screen I28. Horizontally and transversely journaled in the outer end of the sheet-metal side walls I88 is a rock shaft 18 adapted to be manually turned by a hand lever 88. Secured to said rock shaft and extending horizontally clear across the space between the side walls I88 is a shut-off valve 8|. The latter is adapted to be positively held in either its fully open or its fully closed position by a suitable counterweight 82.

The principal feature of this construction is that the flow of coal may be easily shut off without disturbing the sizing screen I28 or its discharge boot. This shutting off of the flow of the coal requires very little effort by reason of the fact that the thickness of the coal stream at the outer end of the adjustable shelf 158w is very small so that the actual arcuate movement required by the shut-off valve 8| to shut off the coal flow is very small.

Fig.'11 illustrates a construction similar to that of Fig. 10 but more desirable in that the straight valve 8| 9 moves vertically upward in its guides 83 and 84 and thereby effects a cutting off of the coal flow without the possibility of lumps of coal becoming jammed against the leading edge of the valve and preventing its complete closure. The actuation of this straight, shut-off valve BI!) is manually effected by a suitable hand lever 889 pivoted to the sizing screen casing at 189 and slidably connected with the valve at 85.

Fig. 12 illustrates a construction analogous to that of Fig. 11 but showing the straight valve 8| I0 mounted at the outer end of the adjustable shelf I 5| 8a. In this construction, also, the pivotal connection 2510 between the front edge of said adjustable shelf and the sizing screen I 2| 8 is located above the floor of said adjustable shelf. This reduces the distance from the outer end of the sizing screen to the adjacent face of the silo;

Fig. 13 illustrates a modified form of loading boot 51H whereby the operator is enabled to easily load the coal in an even bed in the truck or other vehicle. As in the previous constructions this boot is pivoted at 50 to the lower or outer end of the sizing screen l2. Just below its pivot 58, the boot is flared out transversely on its opposite sides at 86, 86. Pivoted at 81, 81 to said boot 5| H and adjacent the upper ends of said flared out portions 86, are a pair of downwardly hanging deflecting plates 88. The lower ends of said plates are held at all times in parallelism and caused to move transversely in unison by a horizontal tie bar 90 which is pivoted at its opposite'ends at 9|, 9| to said deflecting plates 88 and is preferably provided at its central part with a handle 92 to facilitate its manual manipulation.

Byithe use of such a loading boot 5!, the stream. of coal may be directed 'to any desired part of the truck or other vehicle body." To difvert the flow of coal transversely of the truck (toward or away from the silo l0) said loading boot is swung horizontally about its pivots 50 in the one or other direction'as far as is desired, this being preferably accomplished by the operator grasping the handle 92. To divert the stream of coal longitudinally of the truck, the operator moves said handle 92 in the desired Ion-'- gitudinal direction and to the extent desired. It is obvious that the stream of coalmay be diverted simultaneously both transversely and longitudinally and to any desired extent in either of the said directions independently of the diversion of the coal stream in the other direction. For instance,- the operator may pull the handle 92 outwardly any desired amount (swinging the boot about its pivot 58) and simultaneously push said handle 92 any desired amount toward the right (swinging the deflecting blades about their pivots 81). This causesthe flow of coal to be diverted to a certain desired area in the right forward corner of the truck. By this means the coal can be loaded into the truck in a bed as even as may be desired.

I claim as my invention:

1. A mechanism for transferring solid, friable fuel comprising: a bin adapted to contain said friable fuel and having a vertical side wall in which is an opening; a horizontally disposed adjustable shelf arranged below said opening and extending laterally therebeyond and adapted to receive on its upper face the friable fuel emanating from said opening, the outer edge of said shelf being adapted to be disposed inwardly of the line of repose of said friable fuel flowing from said opening; and an inclined screen pivoted to the outer edge of said shelf.

2. A mechanism for transferring solid, friable fuel comprising: a bin adapted to contain said friable fuel and having a vertical side wall in which is an opening; a horizontally disposed and horizontally adjustable shelf arranged below said opening and extending laterally therebeyond and adapted to receive on its upper face the friable fuel emanating from said opening, the outer edge of said shelf being adapted to be disposed inwardly of the line of repose of said friable fuel flowing from said opening; an inclined screen pivoted to the outer edge of said shelf; and means for adjusting the angular position of said angular screen.

3. A mechanism for transferring solid material comprising: a bin adapted to contain said material and having a relatively large opening in its lower portion; a horizontal shelf arranged below said opening and adapted to receive on its upper face the material emanating from said opening, the outer edge of said shelf being adapted to be disposed only slightly inwardly of the line of repose of said material flowing from said opening; and a screen having its inner end connected with the outer edge of said shelf.

4. A mechanism for transferring solid material comprising: a bin adapted to contain said material and having a relatively large opening in its lower portion; a horizontal shelf arranged below said opening and adapted to receive on its upper face the material emanating from said opening, the outeredge of said shelf being adapted to be disposed only slightly inwardly of the line of repose of said material flowing from said opening; and a screen having its inner end pivoted to the outer edge of said shelf.

. JOSEPH A. ALBRECHT.

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