US2840225A - Automatic actuating mechanism for capacity control gates and the like - Google Patents

Description

June 24, 1958 c. s. JONES 2, AUTOMATIC ACTUATING MECHANISM FOR CAPACITY CONTROL GATES AND THE LIKE Filed Jan. 9, 1957 3 Sheets-Sheet 1 CGAW/N 5.. JONES June 24, 1958 c. s. JONES 2,840,225

AUTOMATIC ACTUATING MECHANISM FOR CAPACITY CONTROL GATES AND THE LIKE Flled Jan. 9, 1957 SSheets-Sheet 2 C. S. JONES June 24, 1958 2,840,225 AUTOMATIC ACTUATING MECHANISM FOR CAPACITY CONTROL GATES AND THE LIKE 3 Sheets-Sheet 3 Filed. Jan. 9. 1957 AY E LEE fizz? Comw/v 6. LA NES AUroMA'nc ACTUATING MECHANISM FOR CAPACITY CONTROL GATES AND THE LIKE Corwin S. Jones, Tifiin, Ohio, assignor to Webster Manufacturing, Inc., Tilfin, Ohio, a corporation ofOhio Application January 9, 1957, Serial No. 633,308 9 Claims. (Cl. 19s-s4j The improved actuating mechanism comprising the present invention has been designed for use primarily in connection with under bunker coal conveyors wherein the conveyor is variously fed from the bins above the same in orderthat coal may selectively be withdrawn from one portion ofthe bunker and deposited in another portion thereof, or otherwise disposed of, in accordance with well known principles of operation in connection with compartmented coal bunkers.

Coal bunkers of thisgeneral character are ordinarily provided with a series of gravity feed chutes on the bottom wall thereof, usually one for each bin, the chutes extending downward and into the trough of the conveyor which is common to and underlies all of the bins and 'is substantially coextensive with the length of the bunker.

Such under bunker conveyors are usually covered and, in order to prevent piling up of the coal in the upper run of the conveyor and consequent flooding of the conveyor under the influence of the entire static head of coal issuing from the bunker above the same with the attendant danger of rupturing the conveyor trough or damaging of the moving conveyor drag parts, each chute is provided with a capacity control gate which operates in the manner of a levelling device or strickle to spread to coal, so to speak, at a predetermined level below the ,plane of the top wall of the conveyor trough so that the mass of coal issuing from the gate will pass along the conveyor trough at a safe level and at a rate well within the capacity of the conveyor to handle it. The control gate is movable between a retracted elevated position wherein it is out of thepath of movement of the coal passing therebeneath and issuing from a preceding station along the conveyor run to a lowered operative position wherein its levelling action is effective to maintain the coal issuing from the feeding gate associated with the adjacent bin at'a safe operating level as 'previously described. The present invention, relates specifically to a novel means for automatically actuating such capacity control gates in timed relation to the movement of the feeding gate in such a manner that the control gate will be moved to its effective or operative position during the initial opening movements of the feeding gate and, conversely, moved to its inoperative out-of-the-way position during the final closing movements of the feeding gate.

The invention is not limited to the feeding of under bunker coal conveyors and numerous other uses therefor are contemplated. For example, the present control gate actuating mechanism will be found useful with or without suitable modification, in foundry installations in connection with the movement of sand and gravel; in'mining installations for the movement of crushed ore or the like; in mills or granaries for'the movement of grain and the like in the feeding of grinders; in bituminous or other mixing plants for the proportionate feeding of pulverized or powdered material; in portable or stationary installations for unloading railway dump cars or the like, and in numerous other installations whereincrushed or ground minerals, grain, flour, prepared foodstuff and other loose 2 r or comminuted materials, commonly handled in bulk are transported by conveyor means from one location to another. Irrespective, however, of the particular use to which the invention may be put, the essential features thereof are at all times preserved.

In carryingout the principles of the present invention, there is contemplated the provision of a novel form of linkage mechanism which operatively connects the feeding gate associated'with a bin, hopper, chute or the like and the capacity control gate, levelling device, metering gate, slide or the like associated with the upper run of a conveyor positioned beneath the feeding gate, in such a manner that the movements of the former are transmitted to the latter to render the same effective during the first few inches of opening movement of the feeding gate and to render the same ineffective during the last few inches of closing movement of the feeding gate. This being among the principal objects of the invention, it is a further object to provide a linkage mechanism of this character which is positioned exteriorly of both the feed chute or hopper and the conveyor trough'so that its operation will not be interfered with by movement of the material undergoing handling and so that it will not become contaimnated thereby.

A further object of the invention is to provide a linkage mechanism of this character which will be effective to perform its intended function, without modification, for operatively connecting such feed andcontrol gates regardless of the direction of relative movement between the two movable gates. For example, whether the feed gate of a particular installation is shiftable in a horizontal plane which is parallel, transverse or at an inclineto the axis of swinging movement of the control gate, substantially the same linkage mechanism may be employed for operatively connecting the two movable members.

The provision of a linkage mechanism of the character briefly outlined above which is extremely simple in its construction yet which is effective in its operation; one which is comprised of a minimum number of moving parts and which therefore is unlikely to get out of order; onewhich is readily applicable to existing hopper and conveyor installations; one which is rugged and durable and which, therefore, will withstand rough usage; and one which otherwise is well adapted to perform the services required of it, are further desirable features which have been borne in mind in the production and development of the present invention.

Other objects and'advantages of the invention, not at this time enumerated, will become more readily'apparent as the following description ensues. A y

In the accompanying three sheets of drawingsforming a part of this specification, a preferred embodiment-of the invention, showing the same operatively associated with an under bunker coal conveyor has been shown.

In these drawings:

Figure l is a fragmentary perspective view ofan under bunker coal conveyor in the vicinity-of one ofthe feed chutes associated therewith and showingthe improved linkage mechanism of the present invention operatively appliedto'thebunker feed gate and the'capacity control gate .associatedwith the conveyor installation;

Figure 213 a sectional view taken substantially along the vertical plane indicated by the line 2-2 of Figure 1; Figure 3 is an enlarged detail side elevational view of the bunker feed .g'ate showing a cam member employed in connection with the present invention operativelyi 'ap plied thereto; and

Figure 4 is a side elevational view, partly in of the structure shown in Figure 3.

Referring now to the drawings in detail'and in particular to Figure 1,'the invention'has, purely "forillustrativepurposes, been illustrated in connection with the section,

L i 3 feeding of coal from an overhead bunker to an under bunker conveyor, the former being designated in its entirety at and the latter at 12. On a fragmentary portion of the bunker 10 hasbeen shown herein in the vicinity of one of the feeding stations wherein one of the a sheet metallcasing 22 which is'rectangular in vertical cross section including a bottomwall24, inside and outside sidewalls26 and 28 respectively and a top wall 30. The casing 22 is divided by a, horizontalpartition wall 132 into an upper compartment and a lower compartment 35, the upper run or straightaway portion of the moving conveyor instrumentalities passing through the compartment 34 and the'lower ,orreturn run thereof passing through the compartment 35. The conveyor proper includes theusual chain link assemblies 36 the upper run of the conveyor being 'slidably supported on the partition wall 32 and the lower run of which is slidably supported on the bottomwall 24. Transverse drag bars or flights 38 extend across the link assemblies 36 in spaced relationship and constitute the principal coal impelling members of the conveyor assembly.

At each feeding station, the conveyor casing 22 is provided with a hood portion 40 including inner and outer sidewalls 42 and 44 respectively which are coplanar with the side walls 26 and 28 of the conveyor casing, a top wall 46, a front wall 48 and a rear wall 50. An access opening 52 and closure member 54 therefor may be provided in the rear wall 50. The casing top wall 30 is discontinued in the vicinity ofeach feeding station to permit registry of the lower end of the feed chute with the interior of the casing 22.

The feed chute 20 is formed of sheet metal and may assume any desired configuration, the present illustrated form of chute comprising inner and outer side walls 56 and 58 respectively, and front and rear fwalls 60 and 62 respectively. The inner wall 56 and portions 64 and 65 of the front and rear walls 60 and 62 may be inclined inwardly of the chute as shown and suitable gusset plates 66 may be employed wherever desired to strengthen the structure. An access opening 68 which is closed by a plate- ,70 is formed in the outer wall 58. The chute assembly 20 just described may assume forms other than that illustrated herein and, for convenience of assembly, the illustrated form of chute assembly may be bolted or otherwise secured at its lower rim to an upstanding short rectangular. chute extension: 72 which communicates directly with the conveyor casing 22.

.Rcferring now to Figures 1 and4, the chute 20 is secured. to the underneath side of the floor 18 of the bunker 10 by marginal channel members 74 which may bebolted 'as at 76 or otherwise secured to the floorl8.

Extending across the upper end of the chute 20 is a plate 78 which may be welded in position within the upper rim of the chute and bolted as at 80to the'underneath side of the bunker floor 18. The plate 78 is.provided with a medial depending apron 82 in vertical register with the rectangular opening 16 in the bunker floor and the nature and function of which will be made clear presently.

The opening 16 is adapted to be effectively closed by means of a horizontally reciprocable or slidable feed gate member 84 which may be of one-piece welded construction and which is in the form of a generally rectangular plate having a shallow longitudinally extending trough- 4 operative position on the rollers 88, the depending apron 82 projects downwardly into the trough portion 85 of the gate member 62 with the side walls of the apron in close proximity to'the side walls of the trough portion 85 to inhibit the egress of coal or other particles of the granular material undergoing handling from the trough portion and thus prevent spilling of the material over the gate sides and consequent contamination of the operative gate-impelling mechanism.

Still referring to Figures 1 and 4, the gate proper 84 is shiftable laterally of the opening 16 between a closed 7 position wherein the trough portion 85 thereof is in regissides of the flange portions 86 respectively of the gate member 84 and which mesh with respective pinions 94 carried on a transverse shaft 96 which extends across vand is journalled in bearing blocks 97 secured as at 99 to the side walls 60 and 62 of the chute assembly 20. A hand wheel 98 is mounted on the end of the shaft 96 exteriorly of the chute 20 and, by proper manipulation thereof, the gate member 84. may be moved from its open to its closed positions and vice versa.

Each of the hood portions 40 of the conveyor 12 in the vicinity of one of the feeding stations is provided with a capacity control gate assembly such as has been designated in its entirety at 100 in Figures 1, 2 and 4, the gate assembly operating in the manner of a metering strickle or levelling device to prevent piling up of the coal or other granular material within the conveyor casing 22 and thus clogging the same with the attendant danger of rupture of the casing 22 or of damage to the operative moving conveyor parts. Thecontrol gate assembly inproper 102 which is in the form of a transversely extending strickle plate of L-shape cross sectional configuraclamp the gate member 102 to the 'shaft'108 so that the latter is constrained to follow the rocking movements of the formeix. The effective height of the gate member 102 may bevaried by means of an adjustable extension 112 secured to the flange 104 by pin and slot connections 114 (Figs. 1 and 4); The rock shaft 108 projects outwardly through the outer wall 44 of the hood portion 40 and carries thereon a gate actuating lever 116 by means of which the gate assembly may be operated and the gate member moved between its operative dotted line advanced position as shown in Figure 4 and its retracted inoperative full line position. In the former position thereof wherein the flange 104 and its extension 112 extend downwardly into the trough portion of the con veyor casing 22, this being the normal position of the control gate when the feed gate 84 is open, the lowermost edge of the extension plate 112 serves to control the level of the stream of coal or other granular material which may pass beneath the gate. In the elevated or retracted position of the control gate member 102, the free edge of the extension plate 112 remains above the level of the upper or top wall 30 of the conveyor casing 22 so that-the normal flow of material along the conveyor is unobstructed;

' The arrangement of parts thus far describedis purely conventional and no claim is made herein to any novelty associated with the same, the novelty of the present invention consisting rather in the novelmeans for automatically actuating the'capacity control gate mechanism 100 in timed relationto the movements of the .feed gate 84 under the control of the handwheel 98and whichwill now be described indetail. .C I

Referring now to Figures 21and-3, the rack 92 which is disposed at the rear sideot the chute assembly30, i. e., therack which is nearer the .wall 62, has welded or otherwise secured thereto a cam"block .120. which is formed with a relatively long dependingcam finger122 adjacent the leading edge ofthe block in'the path of travel of the same during opening movement s ofthe gate 84, and with a somewhat shorterdependingcam finger124 adjacent thetrailing edge of the block. The free end of the finger 124 is generally rounded as indicated at.126 for purposes which will become clear presently. The cam block 120 preferably is secured to the rack 9 2-at or near the trailing end of the gate '84which is opposed .to the outer chute wall 58 and isdesigned for cooperation with a train of linkage elements which constitutes the novel linkage mechanism of the present invention and'which serves to operatively connect the feed gate 84 and ,control gate assembly 100so that the latter may followthe movements of the former according to. a predetermined manner. I I I I The linkage mechanism is designated in its entirety at 130 in Figures 1,2 and 4 'and'includes a train of linkage elements extending generallyvertically upwardly from the free end of the lever116 and including, essentially, an upper bell crank lever U assembly132, a lower bell 6 under the influence of the camming action of the dependingfinger 124 formed on the cam block 92 and the lever arm 146 of .the' bell crank lever assembly 132 is swung 144, the free link 136 will be pulled to the right to impart clockwise swinging movement to thebell crank lever 134, thus lowering the outer end of the lever arm 1 60 associated therewith and consequent bodily lowering of the link 162, asiwell as of the outer end of the operating arm 116.. Such lowering of the arm 116 causes clockwise turning movement of the capacity control gate member to bring the same to the lowered operative position wherein it is illustrated in Figure 1. Continued movement of the feed gate member 84 toward its open position, i. e., to the leftas viewed in Fig.2, will, after a relatively short extent of movement of the feed gate member, cause the finger 124 to move over the pin 148 as shown in dotted .lines in Fig. 2 and thereafter move in a horizontal direction away from the pin 148, thus leaving the linkage mechanism in the position likewise shown in dotted lines and wherein the control gate 102 is completely lowered and in its operative position. Furopen position Will have no effect on the linkage mechacrank lever 134 and an intermediate connecting link 136.

The upper bell crank lever assembly 132'is designated for cooperation with the cam block'120 during the initial opening movements of the gate '84 and during the final closing movements thereof, while the bell crank lever 134 is designed for continuous cooperation with the operating lever 116. V

The upper bell crank lever assembly-132 includes a horizontal transverse pivotshaft 140 the ends of which 7 are respectively 'journalled for rocking movement in the wall 62 of.the chuteassembly 20' and inan internal bracket 142 welded or otherwisesecured. to the inner face of the wall 62. The shaft 140'has fixedly mounted on its outer end a depending lever arm 144 and on its inner end an upstanding lever arm 146 'as seen in Fig. 2. The free end of the arm 146 carries an actuating pin 148 which, when the feed gate 84 is in its closed position, extends into the interstice or void 150 existing between the two fingers-122 and 124 as shown in Figure 2. The bell crank lever 134 is pivotally mounted on a bracket 152 by means of a stud 154-which projects from the medial regions of the lever and is rotatably supported in the bracket 152, the latter being welded or otherwise secured to the lower regions of the chute casing 20. A cotter pin 156 orthe like may be employed to maintain the stud 154 in position on the bracket 152. The lever 134 includes a pair of diverging arms 158 and 160 respectively, the former 'arm being connected atits end to one end of the freelink 136 and the latter arm-being connected at its end tozone end of a relatively loose eyelet type of link 162 which link, in turn, has its other end connected to the free end of the operating lever 116. An adjustable counterweight 164 is slidably mounted on the rear end of the operating lever 116 and is designed for cooperation with a series or row of notches 166 for selective placement of the counterweight along the lever to counterbalance the unbalanced force of gravity on the lever and its associated gate structure 130.

In the operation of the linkage mechanism 130, when the feed gate member 84 associated with the bunker bin 14 is initially movedfrom its fully closed position to the left asvviewed in Figure 2 under the influence of the hand wheel 98, the pin 148 (which may be of the anti-friction.roller type if desired) ,is carried to the left nism. which will remain stationary until such time as the ,feed gate member 84.is moved toward its closed position and approaches its completelyclosed position beneath the feed opening 16.

fDuring such return or closing movement of the gate member 84, the relatively short finger 124 will pass to the right as viewed in Fig. 2 over the pin 148 and, thereafterrth e relatively long finger 122 will operate in the manner of a catch and engage the pin and swing the lever 146 of the bell crank lever assembly 132 in a clockwise direction to reverse the movements of the linkage mechanism and elevatethe free end of the operating lever 116 so as to restore the control gate member 102 to its elevated out-of-the-way position above the level of the top wall 30 of the conveyor casing 22.

It is to benoted that, due to the specific nature of the linkage mechanism 130, the control gate will be moved from its elevated inoperative position to its lowered advanced 'operativeposition during the first few inches of opening travel of the feed gate. Conversely, the control gate will be moved from its operative lowered position to its inoperative elevated position during the last few inches of closing travel of the feed gate. By such an arrangementthere is no opportunity for the conveyor casing 22 It is to be further noted that inasmuch as the eyelet typeof link 162 is capable of limited turning movement about its own longitudinal axis and relative to the ends of the lever arms to which it is connected, the linkage mechanism as a whole is readily applicable without modification to feed and control gate assemblies which assume different angular positions relative to each other and wherein the reciprocable feed gate may travel in a linear path of movement which is not necessarily parallel to the axis of turning movement of the control gate.

In compliance with Title 35, U. S. Code, Section 22, a preferred embodiment of the invention has been shown in the drawings and described herein, but it should be understood that the invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in the specification, and that the appended claims should be construed as broadly as the prior art will permit.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. In an apparatus for handling loose comminuted or tion,: a bin having a bottom wall provided with an opening therein-for thedischargeby gravity of the material ,therethrough, a horizontally reciprocablefeed gate movable between a closed position wherein it"closes said t opening and an open positionfwherein it uncovers said opening, a trough-like conveyorcasing extending below said opening and having a'trough bottom, side walls and an open top in vertical register with said opening, a movingconveyor having an upper 'run supported on the trough bottom and movable therealong in one direction for conveying the material discharged into the casing from 'said opening along-the casing in saidone direction, a ca pacity control gate including a strickle plate pivoted within the casing in thep ath' of movement of the material di scharged into the casing from said opening, said plate being capable of swinging movement about aflhorizontal axis between a ,loweredyoperative position wherein it limits the flow of material passing along the casing to an elevated inoperative position wherein it is'out of the pathof such material, an operating lever positioned exteriorlyofthe casing and operatively connected to the strickle plate, for swinging movements in .unison therewith, a cam finger mounted on said feed gate and movable bodily therewith, a bell crank lever mounted for swinging movement about a fixed horizontal axis normal to the direction of movement of said feed gate and 'having an actuating pin on one arm thereof positioned in the path of movement of saidfinger .and adapted to be dis-' placed by the latter during the initial opening movements of said feed gate, and means operatively connecting the other arm of said bell crank lever to said operating lever for translating the movements of the former into movements .of the latter.

2. In an apparatus for, handling loose comminut'ed other materials commonly handled in'bulk, in combina tion, a bin having a bottom wall provided with an opening thereinxfor the discharge by gravity of'the material therethrough, a horizontally reciprocable feed gate movable between a closed position wherein it closes said open ing and an open positionfiwherein it uncovers saidopen charged into the casing ,from said opening, said plate being capable of swinging movement abouta horizontal axis between a lowered operative position whereinit limits the flow of material passing along the casing to an elevated inoperative position wherein it is out of the path of such material, an operating lever positioned exteriorly of the casing and operatively connected to the strickle plate forswinging movements in unison therewith, a cam finger mounted on said feed gate and movable bodily therewith, a first bell crank lever mounted for swinging movement about a fixed horizontal, axis normal to the direction, of movement of said feed gate and having ,an actuating pin on one arm thereof positioned in the path of movement of said finger during the initial opening movements of ,said feed gate, a second bell crank lever mounted for swinging, movement about a fixed'axis normal .to the direction'of movement of said feed gate and spaced from said first axis, a link connecting the other arm of'said first bell crank lever to one arm of the second bell crank lever, and a link connecting the other iarm of said second bell crank lever to said operating ever.

, 3. In an apparatus for handling loose comminuted or other materials commonly handled in bulk, the combination set forthin claim 2 wherein the extent of said cam finger on the feed gate is of less extent than the effective "radial extent of one arm on thefirs t ibell crank lever whereby continued opening, movements of t the feed gate a t r Sa d ini i cvs s th re wi l pau e h m fi er 1 1o r p: over said actuating pin. and; move. away therefrom;

14; 'In an apparatus for handling loose comminuted or other materials commonly handled in ,bulk,'the combinationset forth in claim 2 wherein the extent of saldcam whereby continued opening movements of the feed gate after said initial movements thereof will cause the cam finger to trip over said actuating pin and move away therefrom, and a catch finger mounted on said feed gate and positioned to engage said actuating pin during the closing movements of said'feed gate.

5. In an apparatus for handling loose comminuted or other materials commonly handled in bullcthe combination set forth fin'claim 4 wherein said catch finger and cam finger are disposed on opposite sides of the actuating 'pin when 'theifeed gate is in its .closed positionand wherein said fingers are spaced from each other a distance substantially equal to the'width'of said actuating pin.

6 In an apparatus for handling loose comminuted or other materials commonly handled in bulk, in combination, aibin having a bottom w all provided with an opening therein for the discharge by gravity of the material therethrough, a horizontally"reciprocablefeed gate movable between a closed position whereinit closes said opening andjan open position wherein it uncovers said opening, a trough-like conveyor casing extending below said opening and having a trough bottom, side walls and an open top in vertical register with'said opening, a

moving conveyor having an upper run supported on the trough bottom and movable therealong in one direction for conveying/the material discharged'into the casing from said openingalong thecasing in said one direcabout a horizontal axis between a lowered operative position wherein it limits the flow of material passing along the casing to an elevated inoperative position wherein it is outjof the path of such material, a cam finger mounted on said feed gate and movable bodily therewith, a first bell crank lever mounted for swinging movement about a fixed horizontal axis normal to the direction of movement of said feed gateand having an actuating pin on one arm thereof positioned in the path of movement of said finger and adapted to be displaced by the latter during the initial opening movements of said feed gate, a second bell crank lever mounted for swinging movement about a fixed axis parallel to and spaced from said first axis, a link' connecting the other arm of said first bell crank lever to one'arm of the second bell crank lever, and a'link connecting the other arm of said second bell crank lever to said strickle plate.

7. In an apparatus for handling loose comminuted or other materials commonly handled in bulk, the combination set forth in claim 6 wherein said last mentioned link is in the'forrn of an eyelet loosely connected at its ends to said other arm ofthe second bell crank lever and to said strickle plate for limited turning movement relative to the same. i i

8. In an apparatus for handling loose comminuted or other materials commonly handled in bulk, in combination, a bin having a bottom wall provided with an opening therein for the discharge by' gravity of the material therethrough, a horizontally reciprocable feed gate movable between a closed position 'wherein it closes said opening and an open position wherein it ,uncovers said opening, a trough-like conveyor casing extending below said openmg'andhaving a trough bottom, side walls andfan open topjn vertical register with said opening, a

moving conveyor having an upper run supported on the trough bottom and movable therealong in one direction for conveying the material discharged into the casing from said opening along the casing in said one direction, a capacity control gate including a strickle plate pivoted within the casing in the path of movement of the material discharged into the casing from said opening, said plate being capable of swinging movement about a horizontal axis between a lowered operative position wherein it limits the flow of material passing along the casing to an elevated inoperative position wherein it is out of the path of such material, an operating lever positioned exteriorly of the casing and operatively connected to the strickle plate for swinging movements in unison therewith, a cam finger mounted on said feed gate and movable bodily therewith, a bell crank lever mounted for swinging movement about a fixed horizontal axis normal to the direction of movement of said feed gate and having an actuating pin on one arm thereof positioned in the path of movement of said finger during the initial opening movements of said feed gate, means operatively connecting the other arm of said bell crank lever to said operating lever for translating the movements of the former into movements of the latter, the extent of said cam finger on the feed gate being less than the effective radial extent of said one arm of the bell crank lever whereby continued opening movements of the feed gate after said initial movements thereof will cause the cam finger to trip over said actuating pin and move away therefrom, and a catch finger mounted on said feed gate and positioned to engage said actuating pin during the closing movements of said feed gate.

9. In an apparatus for handling loose comminuted or other materials commonly handled in bulk, in combination, a bin having a bottom wall provided with an opening therein for the discharge of material therethrough by gravity, a horizontally reciprocable feed gate movable between open and closed positions with respect to said opening, a relatively narrow shallow conveyor trough extending below said opening and having a trough bottom, side walls and a top wall, there being an opening in said top wall in vertical register with said discharge opening in the bin, a chute establishing communication between said openings, a conveyor proper having flights of less height than the full height of the trough and mounted to operate on said trough bottom in one direction, a capacity control gate including a strickle plate pivoted within the conveyor trough in the path of movement of material discharged into the casing through said chute, said strickle plate being movable between a lowered operative position wherein it limits the flow of material passing along said trough to an elevated inoperative position wherein it is out of the path of movement of such material, an operating arm positioned exteriorly of the trough and operatively connected to the latter for movements bodily therewith, a cam finger mounted on said feed gate and movable bodily with the latter, a first bell crank lever mounted on said chute for swinging movements about a fixed horizontal axis normal to the direction of movement of said feed gate, and having an actuating pin on one arm thereof positioned in the path of movement of said finger and adapted to be displaced by the latter during the initial opening movements of said feed gate, a second bell crank lever mounted on said chute for swinging movements about a fixed axis parallel to and spaced from said first axis, a link connecting the other arm of said first bell crank lever to one arm of the second bell crank lever, and a link connecting the other arm of said second bell crank lever to said operating arm.

References Cited in the file of this patent UNITED STATES PATENTS 2,389,566 Thomas Nov. 20, 1945 FOREIGN PATENTS 319,219 Germany Feb. 28, 1920

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