US3169797A

US3169797A - Material collecting means for continuous mining machine

Info

Publication number: US3169797A
Application number: US231096A
Authority: US
Inventors: Richard C Lundquist
Original assignee: Goodman Manufacturing Co LP
Current assignee: Goodman Manufacturing Co LP
Priority date: 1962-10-17
Filing date: 1962-10-17
Publication date: 1965-02-16
Anticipated expiration: 1982-02-16

Description

1965 R. c. LUNDQUIST 3,169,797

MATERIAL COLLECTING MEANS- FOR CONTINUOUS MINING MACHINE Filed Oct. 17, 1962 3 Sheets-Sheet 1 INVENTOR, Richard C lunoqulsf ATTYS.

Feb. 16, 1965 R. c. LUNDQUIST 3,169,797

MATERIAL COLLECTING MEANS. FOR CONTINUOUS MINING MACHINE Filed Oct. 17, 1962 s Sheets-Sheet 2 INVENTOR. Pic/70m 6. Zunoyw'sl Feb. 16, 1965 R. c. LUNDQUIST 3,169,797

MATERIAL COLLECTING MEANS FOR CONTINUOUS MINING MACHINE Filed Oct. 17, 1962 3 Sheets-Sheet 3 F5 .4 L I7 7 INVENTOR. k/b/zaro C Zunogzw'sf ATTYS.

United States Patent 3,169,797 MATERIAL CGLLEE'I'ING MEANS FUR CON- TINUGUS MINING MAQHINE Richard E. Lnndqnist, Palos Heights, Ill assignor to Gcodinan Manufacturing tlompany, Chicago, IIL, a corporation of Illinois 7 Filed Oct. 17, B62, Ser. No. 231,096 11 Claims. ((13. 299-64) This invention relates to improvements in continuous mining machines and more particularly relates to an improved means for collecting and transferring the mined material to the conveyor of themachine.

A principal object of the invention is to improve upon the continuous mining machines heretofore in use by providing a simplified and improved cuttings collecting device following the mining head during mining and forming a material collecting and transferring hopper of substantially uniform width in all vertical positions of the mining head, for transferring the mined material onto the conveyor of the machine.

A further object of the invention is to provide an improved means for collecting the material mined by ripper type mining heads and transferring the material to the conveyor of the machine in the form of aprons extending laterally from opposite sides of the conveyor of the machine and longitudinally pivoted thereto to be extended for substantially thewidth of the working place when the mining head is in position to be sumped into the working face along the ground and following the mining head during upward cutting movement thereof and extensible during the operation of following the mining head to present a material collecting area extending substantially to the ribs of the working place during the entire operation of mining a working place.

A still further object of the invention is to provide an improved form of continuous mining machine having a transversely pivoted boom extending in advance of the main frame of the machine over a material collecting conveyor, and having a transversely extending mining head supported at its forward end to mine by rotational movement of the mining head and upward feeding movement thereof effected by upward swinging movement of the boom, in which aprons longitudinally pivoted to opposite sides of the conveyor of the machine form a material collecting means transferring material to the conveyor-of the machine and are moved vertically about their longitudinal pivotal axes upon vertical movement.

of the boom under the control of the boom, and have side boards extending along and pivotally connected to the outer ends thereof extending the aprons during upward pivotal movement thereof to maintainthe material collecting areas of the aprons into positions at substantially the ribs of the working place during the entire scope of vertical feeding movement of the boom.

These and other objects ofthe' invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein FIGURE 1 is a top plan view of a continuous mining machine constructed in accordance with the principles of the invention;

FIGURE 2 is an enlarged partial fragmentary view in side elevation of the forward end portion of the machine, showing the boom supporting the mining head in position to be sumped into a working face;

FIGURE 3 is a fragmentary plan view of one side of the machine, showing a material collecting apron and side board in the position shown in FIGURES land 2;

FIGURE 4 is a transverse sectional view taken substantially along line 44 of FIGURE 2; and

FIGURE 5 is a diagrammatic view showing an illusice movement of the material carrying aprons of the machine.

' In FIGURES 1 and 2 of the drawings, I have shown a continuous mining machine 10 mounted on laterally spaced continuous traction tread devices 11. The traction tread devices 11 serve to transport the machine from working place to working place and to sump a rotary mining head 12, extending transversely of a main frame I3 of the machine into the working face of a mine. The mining head 12 is a drum type of mining head having cutter bits 14- projecting from the periphery thereof and isfed vertically along the working face from the floor to the roof of the mine by a boom 15 supporting the min-v ing head at its forward end, and transversely pivoted to the main frame 13 of the machine on transverse pivot pins 16. v

The continuous mining machine It is commonlycalled a ripper type of mining machine and operates on principles similar to those shown and described in my application Serial No. 67,267, filed November 4, 1960, now forfeited. 7

As shown in FIGURES -1 and 2, the boom arm 15 is transversely pivoted to the main frame of the machine along opposite sides of a conveyor 17 and extends over the top of said conveyor in advance of the forward end thereof and supports the rotary mining head 12 at its forward end for rotation about an axis extending transversely of the main frame of the machine,

Motors 19 extend along opposite sides of the boom 15 and have speed reducer housings 20 at the forward ends thereof, formingcontinuations of the motor housings. The speed reducer housings 26 contain conventional speed reduction gearing (not shown) therein.

The speed reduction gearing contained in the housing 20 forms a means for driving flexible and universal drive connections 21, driving the mining head 12 through bevel geared drive connections (not shown) in a manner similar to that shown and described in my application Serial No. 67,267, and no part of the present invention so not herein shown or described further. I i I The boom 15 and mining head 12 are elevated by hydraulic jacks 22 extending along opposite'sides of an in the form of a piston rod 26, pivotally connected between .to discharge trative form of fluid system controlling vertical swinging connector ears 27 on a transverse pivot pin 29. The connector ears 27 depend from an upper plate portion 3t) of the boom 15. The inclined elevating frame structure 23 of the conveyor, includes parallel spaced side plates SLtransversely pivoted at their rear ends to the main frame 13 on transverse pivot pins 32 shown in FIGURE 2 as being disposed above the pivot pins 16 and in general vertical alignment therewith. The side plates 31 slidably extend within side plates 33 of the conveyor'17, extending along the main 7 frame 13 in parallel relation with respect .to each other. The side plates 33 terminateint-o flexible sidewalls 34, connecting the side plates 33 ton; rear laterally swingable discharge trough section 35 of the conveyor, positionable like. a

The material moving structure of the conveyor 17 is 2 the mined material into shuttle cars and the forward end thereof.

wardly of the'main frame 13, on pivot pins 41. The jacks 39 are pivoted at their opposite ends between connector brackets 42, space-d outwardly of the side plates 31 of the:

frame structure 23, on pivotpins 43. The jacks 39 are provided to elevate the inclined elevating frame structure 23 abovethe ground when it is desired to tram the Inachine from working place to-working place and toaccommodate a ground engaging shoe45 extending transversely of the inclined frame structure 23 along the bottoms of the side plates 31 and laterally beyond said side plates to Tslid- .ably engage the ground during the operation of mining.

ends to saidrnain frame, between ears as extending for- 'Referringnowin particular to the extensible material collectingand transferring hopper of the invention, collooting and transferring the material mined by the mining head12gbnt0the conveyor '17, an apron 47 extends along :the upper end portion of each sidepla-te 3l,"for a portion of the lengththereof. 1 Each apron interleaves the upper end portion of an associated side plate and is pivotally connected thereto as by a' hinge pin 49 extending generally parallel to the sideplatefil. Each apron 47 has an inclined shovel-like plate fi lforrning a continuation of the clined downwardly toward the ground at a steeper angle than the angle of the apron 4'7 and engages the ground at its forward end when the apron is in the position shown 7 in FIGURE 2. The shovel-like plates 5 tl overlap the outer end portions of an inclined shovel-like plate 51, extending across the front of the conveyor and connected to the shoe 45 at its lowerend. c y c The inclined shovel-lilre plates 50; 50 and 51, provide a'widejfront shovel edge to beforced under the pile of loose coal mined, when the mining head 12 is in position ,to be sumped along theground and issumped into the mine face to initiate a vertical mining operation from the 7 floor to the-root of the mine.

Each apron" 47 is interleaved at-its outer side by aside Each shovel-like plate: 50 is inhasan intale line 71 leading from afluidstorage tanlc 72. i

The output of the pump 76 is connectedwith a variable pressure relief valve 73 through a pressure line '74. The variable pressure relief valve 73 governs the pressure in a pressure line 75 leading from said relief-valye and connected with a four way valve '76. A return line 77 leads a from the relief valve 73 tothe tank 72.

The four way valve 7s isconnected with the head ends 7 of the cylinders 56by pressure lines 78." The four way valve 76 is operable to raise and lowertheaprons 47 by 'manual operationof :the valve; 'The valve 76' also may continuously supply fluid under pressure to the head ends of the cylinders 56 2\nd. bias the aprons '47 into upwardly extended relation withrespecttothe conveyor 17 into the positions shown by dot dash'lines in FIGURE 4. The

relief valve '73 is set to govern the pressure'in the cylinders 56 and to accommodate downward movement of the aprons 47 upon engagement of thetop surfacesof said aprons with stop legs 79 depending from opposite sides of the'boorn l5 whenthe operator may neglect to turn the valve '76fto supply lluid under pressure to the piston rod ends of the cylinders 56, to lower the aprons'47, or where a it may be desired to have the aprons automatically follow the boom and mining head. Pressure lines lead from the valve 76' to the pistonrod ends of the cylinders 56, to V retract aprons by operation ot-the valve '76.

Duringthe operation of surnping the mining head 12 into the working face'when positioned to'cut along the board 53 pivotally connected to said apron by a pivot pin 54-, extending parallel to the pivot pin 49. a

The

aprons

47, 47 are raised and loweredtogether by f

hydraulic jacks

55, 55. As shown in'FlGURE 4, "each hydraulic jack 55 includes a cylinder 56 having an ea; 57 extending from the'headend thereof between parallel splacejd brackets -591exten'ding' laterally of the {side plate" 7 31 andpivotally connected theretoasibya pivotpin 6t). A piston rod 61 extensible from the cylinder 56 ex- 1 tends between connector brackets fil depending from'the "underside ,of the apron 47 and is 'pivotally connected there to 'as'byapivot pin.63. I r

The sideboards 53 are moved from the upwardly extended positions shown in FIGURES l, 2, 3 and 4 to the outwardly extended positions shown by broken lines in links 65 are pivotally connected to rigid arms s7 welded *or}.otherwise secured' to the undersurfaces' of the side boards 53 and extending downwardly therefrom, when the axes of the hinge pins 49, the; side boards 53 will be pivoted material mined by veyor 17 the mining: headll onto, the conground, there will be a space between the bottoms of the stop legs v 79 and the ap'ron's 47. As, however, the mining head is :surnpedinto the working face and upward feeding movement thereof is started, the valve 76' may be turnedto supply fluid under pressure to the head ends a of the cylinders 55 and move the, aprons 4+7 upwardly about the hinge pins 49 into engagement with the stop 7 legs '79. The hand may then be taken from the controls I of the valve 76 and the aprons 47 may move upwardly with the boom '15 following the stop legs 79 to their extended positions shownin FIGURE 4, limited by the strokes of the hydraulic jacks 55. If required, the boom may then move away from the aprons 47 to feed'the mining head 12 upwardly to the roof of the mine.

Upon" downward'rnovementof the boomlithe stop

legs

79,79 engaging the

aprons

57, 47 Willrnove said yaprons downwardly about the axes of the hinge pins 49 against the hydraulic bias of the cylinders controlled by the'relief valve 73. 5 7 Durin'g the operation of surnping the mininghead 12V vinto the working face, the aprons 47 and Sideboards 53 may be retainedin the upright positions shown in FIG- :URE 4. As the mining head is sumped into the working i v 'taceito the required depth and the hydraulic jacks 22 are i FIGURE -'4 by links connected to the outer sides of the side walls 31, on pivot pins 66a The outer ends of the a side boards are in their upwardly extended positions {shown in FIGURE 4. Pivotjpins 69 pivotallyconnect the ,;"-links 65'to the-arms67.

" Thus, as the aprons 47 are pivoted upwardly aboutthe V putinto. operationto feed the boorn'ls and mining head vl2, upwardly towards the roof of the'mine, the vaive '76 w may beturned'by the operator of'the machine to admit fluid underpressureto the head endsof the cylinders 56 and move the aprons 47 upwardly to follow the boom 15 and to effect opening of the sideboardsl 53 as the aprons '47 move upwardly. The relief valve 73 may be set to ,supply just enough pressure to cause the aprons to fol low the stop legsfik The operator of the machine. may

. thus remove'hishand fromthe control lever'for the valve 1.76 and the aprons'47 will be swung upwardly under con- An'illustrative form of fluid pressure diagram showing a a 7 part of the'fluid' pressure system of the machine and the VI fluid pressure connections to the hydraulic 'jacks 55, is

shown in FIGURE 5. As shownwin this figure a pump 7% trol of the stop legs- 79' until they'reach their limit of upward travel.

Upon lowering movement of-the boom, the stops 79 en- V gaging the aprons 47 will pivot said aprons downwardly against the hydraulicibias in the cylinders 56, until the f stops 7 reach the lower ends of their travel. Where desired the valve 76 may then be operated to admit fluid underpressureto the pistonrod ends of the cylinders 56 and lower the aprons 47 to the positionsshown'in FI URE 4.

The boorn arm ls also has a stop depen di'rigfrom itstorward end portion just rearwardly Qf'lhfi mining head 12. This stop is engageable with a stop 82 on the shoveliike plate 51, to limit downward movement of the mining head 12 and to prevent the mining head from cutting into the shovel-like plates 50 and 51.

It may be seen from FIGURE 2 that when the mining head 12 is cutting along the ground the stop 81 is spaced above the abutment 82. This spacing is provided to enable the mining head 12 to be adjusted to out below the floor line, when desired.

The aprons 47 and side boards 53 thus form an extensible hopper of a substantially uniform width in all positions of the aprons with respect to the conveyor 17, for collecting and transferring the material mined onto said conveyor.

It should here be noted that while the aprons 47 and side boards 53 usually follow the mining head during the mining operation, that said aprons and side boardsneed not follow the mining head, but may remain in their lowermost positions shown in FIGURE 4 and allow the mined material to be deposited thereon, and then may be periodically raised to cause the material deposited thereon to flow onto the conveyor.

While I have herein shown and described one form in which my invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from the spirit and scope of the novel concepts thereof as defined by the claims appended hereto.

I claim as my invention:

1. In a continuous mining machine,

a main frame,

a boom transversely pivoted to said main frame and extending in advance thereof,

a rotary mining head supported on said boom for rotation about an axis extending transversely of said main frame,

means for vertically moving said boom with respect to said main frame and feeding said mining head vertically along a mine face,

a conveyor extending along said main frame and having an inclined elevating forward end portion extending in advance of said main frame in a downwardly inclined direction into engagement with the ground,

inclined aprons extending along opposite sides of said conveyor and laterally therefrom and mounted on said conveyor for angular movement with respect thereto about axes extending longitudinally of said conveyor and parallel to the plane of travel thereof and engaged by said boom when said boom is in a lowermost position, a

and fluid pressure operated means pivotally connected between said conveyor and aprons, pivotally moving said aprons upwardly to follow said boom and form an inclined hopper terminating at said conveyor.

2. A continuous mining machine in accordance with claim 1 wherein side boards are'pivotally connected to and extend along the outer sides of said aprons and cooperate with said aprons to form a movable hopper of uniform width for transferring the mined material to said conveyor, and wherein linkage connections are provided between opposite sides of said conveyor and said side boards to extend said side boards outwardly with respect to said aprons upon upward pivotal movement of said aprons.

3. In a continuous mining machine,

a main frame,

a rotary mining head supported by said boom for rotation about an axis extending transversely of said main frame,

a conveyor extending along said main frame and having an inclined elevating trough portion extending in advance of said main frame downwardly into position to engage the ground, the inclined elevating trough portion of said conveyor having a steeply inclined shovel plate extending across the forward end thereof to a position adjacent the ground,

material retaining aprons extending along opposite sides of said elevating trough portion and pivotally connected thereto for movement about axes extending longitudinally of said trough portion,

hydraulic jack means connected between said trough portion and said aprons for pivoting said aprons upwardly,

and engaging connections between said boom and said aprons accommodating said aprons to follow said boom upon angular upward movement thereof upon the admission of fluid under pressure to said hydraulic jack means to pivot said aprons upwardly, and moving said aprons downwardly upon downward movcment of said boom upon the release of pressure in said hydraulic jack means.

4. In a continuous mining machine,

a main frame,

a conveyor extending along said main frame and having an inclined elevating trough portion extending in advance of said main frame downwardly into position to engage the ground, and having parallel spaced side walls extending therealong having an inclined shovel-like plate extending across said side walls in advance thereof in position to engage the ground,

material collecting and transferring aprons extending along the upper end portions of said side walls and laterally therefrom,

means pivotally connecting said aprons to said side walls for upward movement about axes extending longitudinally of said walls,

hydraulic jack means pivotally connected between said side walls and aprons for raising and lowering said aprons about their axes of connection to said side walls,

side boards extending along the outer sides of said aprons and pivotally connected thereto for movement about axes extending parallel to the axes of connection of said aprons to said side Walls,

and linkage connections between said side walls and said side boards, pivoting said aprons outwardly upon angular upward movement of said aprons to extend said aprons laterally to maintain a uniform cuttings collecting surface upon upward feeding movement of said mining head.

5. A continuous mining machine in accordance 'm'th claim 4 wherein a hydraulic circuit is provided to said jacks including a control valve and a relief valve to bias said aprons into angular upward extended relation with respect to said conveyor, and wherein an engaging connection is provided between said boom and said aprons to pivot said aprons downwardly upon downward travel of said boom and mining head and to accommodate said aprons to travel upwardly with said boom.

6. A continuous mining machine in accordance with claim 5 wherein the engaging connection comprises a pair of stop legs depending from said boom and having controlling engagement with said aprons.

7. In a continuous mining machine,

a main frame,

a conveyor extending along said main frame and having an inclined elevating trough portion extending in advance ofsaid main frame downwardly into position to engage the ground, and having parallel side walls having a plow plate extending across the forward ends thereof and in advance thereof for collecting the material mined by said mining head and transferring the material onto said conveyor including inclined aprons extending along said side walls and pivotally connected thereto for movement about axes extending longitudinally thereof generally paral lel to the plane of said conveyor,

hydraulic jack means pivotally connected between said side walls and aprons for pivoting said aprons upwardly to follow said boom upon upward movement thereof,

side board extends along the outer sides of said aprons and longitudinally pivoted thereto,

control arms extending downwardly of the outer sides of said side boards, said side boards with said aprons forming a vertically movable hopper transferring the mined material tosaid conveyor,

and control links connected between said control arms and side walls and maintaining said side boards in generally upright positions when said conveyor is in engagement with the ground and moving said side boards angularly outwardly with respect to said aprons upon upward pivotal movement of said aprons.

8. A continuous mining machine in accordance with claim 7, wherein said boom has stop legs depending therefrom and having controlling engagement with said aprons for moving the said aprons outwardly upon downward movement of said boom and accommodating upward movement of said aprons upon upward movement of said boom to feed said mining head vertically along a mine scams 9. A continuous mining machine in accordance with claim 8 wherein a fluid pressure circuit is provided to supply fluid under pressurerto said jack means and bias said aprons to follow said boom upon upward movement thereof and wherein a relief valve loaded to maintain said aprons into engagement with said stops is provided in said circuit.

10. In a conveyor having an inclined elevating forward end portion having parallel spaced side walls extending therealong andan endless chain and flight conveyor movable along said side walls in the space therebetween,

a hopper for said inclined elevating forward end portion of said conveyor for transferring the mined material onto said conveyor comprising aprons extending along opposite sides of said in clined elevating forward end portion of said conveyor and longitudinally pivoted to said side walls,

5% hydraulic jack means connected between said side Walls and aprons for raising and lowering said aprons about their axes of connection to said conveyor,

side boards extending along the outer sides of said aprons and pivotally connected thereto for movement about axes extending parallel to the aboom transversely pivoted to said main frame and extending in advance thereof, a rotary mining head supported on said boom for rotation about an axis extending transversely of said main frame, means for vertically moving said boom with respect to said main frame and feeding said mining head vertically along a mine face, a conveyor extending'along said main frame and having an inclined elevating forward end portion extending in advance of said main frame and inclined downwardly from said main frame toward the ground, said inclined forward end portion having a shovel-like plate extending across the forward end thereof to the ground, a inclined aprons extending along and outwardly of op posite sides of said inclined elevating portion of said conveyor and pivotally connected thereto for 'movement about axes extending longitudinally of said conv y means for pivoting said aprons upwardly about said axes to form a vertically movable hopper to collect and transfer materiai onto said conveyor, .said aprons each having a forward shovel-like extension overlapping said shovel-like plate and forming lateral continuations thereof when said aprons are in their lowermost positions of adjustment, side boards extending along said aprons and longi tudinally pivoted to the outer sides thereof and extending upwardly therefrom when said mining head is positioned along the ground, and links pivotally connected between the. undersides of said side boards and opposite sides of said inclined elevating portion of'said conveyorto effect movement of said side boards outwardly toward the ribs of a working piace upon angular iupwardmovement of said aprons toward each other.

References Cited inthefile of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE (1F CORRECTION Patent No. 3,169,797 February 16, 1965 Richard C. Lundquist It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patentshould read as corrected below.

Column 7, line 23, for "board extends"'read boards extending Signed and sealed this 17th day of August 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Altesting Officer Commissioner of Patents

Claims

1. IN A CONTINUOUS MINING MACHINE, A MAIN FRAME, A BOOM TRANSVERSELY PIVOTED TO SAID MAIN FRAME AND EXTENDING IN ADVANCE THEREOF, A ROTARY MINING HEAD SUPPORTED ON SAID BOOM FOR ROTATION ABOUT AN AXIS EXTENDING TRANSVERSELY OF SAID MAIN FRAME, MEANS FOR VERTICALLY MOVING SAID BOOM WITH RESPECT TO SAID MAIN FRAME AND FEEDING SAID MINING HEAD VERTICALLY ALONG A MINE FACE, A CONVEYOR EXTENDING ALONG SAID MAIN FRAME AND HAVING AN INCLINED ELEVATING FORWARD END PORTION EXTENDING IN ADVANCE OF SAID MAIN FRAME IN A DOWNWARDLY INCLINDED DIRECTION INTO ENGAGEMENT WITH THE GROUND, INCLINED APRONS EXTENDING ALONG OPPOSITE SIDES OF SAID CONVEYOR AND LATERALLY THEREFROM AND MOUNTED ON SAID CONVEYOR FOR ANGULAR MOVEMENT WITH RESPECT THERETO ABOUT AXES EXTENDING LONGITUDINALLY OF SAID CONVEYOR AND PARALLEL TO THE PLANE OF TRAVEL THEREOF AND ENGAGED BY SAID BOOM WHEN SAID BOOM IS IN A LOWERMOST POSITION, AND FLUID PRESSURE OPERATED MEANS PIVOTALLY CONNECTED BETWEEN SAID CONVEYOR AND APRONS, PIVOTALLY MOVING SAID APRONS UPWARDLY TO FOLLOW SAID BOOM AND FROM AN INCLINED HOPPER TERMINATING AT SAID CONVEYOR.

10. IN A CONVEYOR HAVING AN INCLINED ELEVATING FORWARD END PORTION HAVING PARALLEL SPACED SIDE WALLS EXTENDING THEREALONG AND AN ENDLESS CHAIN AND FLIGHT CONVEYOR MOVABLE ALONG SAID SIDE WALLS IN THE SPACE THEREBETWEEN, A HOPPER FOR SAID INCLINED ELEVATING FORWARD END PORTION OF SAID CONVEYOR FOR TRANSFERRING THE MINED MATERIAL ONTO SAID CONVEYOR COMPRISING APRONS EXTENDING ALONG OPPOSITE SIDES OF SAID INCLINED ELEVATING FORWARD END PORTION OF SAID CONVEYOR AND LONGITUDINALLY PIVOTED TO SAID SIDE WALLS, HYDRAULIC JACK MEANS CONNECTED BETWEEN SAID SIDE WALLS AND APRONS FOR RAISING AND LOWERING SAID APRONS ABOUT THEIR AXES OF CONNECTION TO SAID CONVEYOR, SIDE BOARDS EXTENDING ALONG THE OUTER SIDES OF SAID APRONS AND PIVOTALLY CONNECTED THERETO FOR MOVEMENT ABOUT AXES EXTENDING PARALLEL TO THE AXES OF PIVOTAL MOVEMENT OF SAID APRONS, AND LINKAGE CONNECTIONS BETWEEN SAID SIDE WALLS OF SAID CONVEYOR AND SAID SIDE BOARDS PIVOTING SAID SIDE BOARDS OUTWARDLY UPON ANGULAR UPWARD MOVEMENT OF SAID APRONS TO MAINTAIN THE WIDTH OF SAID HOPPER SUBSTANTIALLY UNIFORM IN ALL VERTICAL POSITIONS OF SAID APRONS WITH RESPECT TO SAID CONVEYOR.