US2475225A - Reversible screw feeder and crusher mechanism with means to automatically eject indestructible oversize foreign matter - Google Patents

Description

July 5, 1949. R. N. DULANEY 2,475,225

REVERSIBLE SCREW FEEDER AND CRUSHER MECHANISM WITH MEANS TO AUTOMATICALLY EJECT INDESTRUCTIBLE I OVERSIZE FOREIGN MATTER Filed May 24, 1944 3 Sheets-Sheet 1 11. I l I f I I I W {H 13 15 60 38 J7 41 m T l7 lg 07 59 3/ 23 7 2/ .52 3

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July 5, 1949. R. N. DULANEY 2,475,225 REVERSIBLE SCREW FEEDER AND CRUSHER MECHANISM WITH MEANS TO AUTOMATICALLY EJEC'I' INDESTRUCTIBLE OVERSIZE FOREIGN MATTER 3 Sheets-Sheet 2 Filed May 24, 1944 awe/whom FoM f/VT 17a @2744 y 1949. R. N. DULANEY 2,475,225

REVERSIBLE SCREW FEEDER AND CRUSHER MECHANISM WITH MEANS TO AUTOMATICALLY EJECT INDESTRUCTIBLE OVERSIZE FQREIGN MATTER Filed May 24, 1944 5 Sheets-Sheet 3 m n m M 7 m R Patented July 5, 1949 UNITED STATES PATENT OFFICE REVERSIBLE SCREW FEEDER AND CRUSHER MECHANISM WITH S TOLAUTOM ATI- CALLY EJECT INDESIRUCTIBLE OVER SIZE FOREIGN MATTER;

Robert N. Dulaney, Chattanooga; Tenn: Eliza-.- beth M. Dulaney, executrixof said Robert N. Dulaney, deceased, assignor of one-half to Ralph Burch, Washington, D. C.

Application May 24, 1944;Serial' No; 537,130

12 Claims.

The invention relates to a material feeding mechanism, and more especially to a'feeder and ejector mechanism for a screw-feed type of conveyor,-such for exampleas a-coal stoker, directing soft, semi-lumpor other fuel material to a furnace, or the like; for the burning thereof.

The primary object of the invention is the provision of mechanism of this character, wherein stoppageor damage thereto by foreign objects will-be prevented, during the operation thereof in conveying coal or other material thereby, the mechanism being novel in its construction, and unique in the workingofthesame, as the presence of any foreign matter inthematerial will be ejected from the mass. without damage to the said mechanism or the stoppage in the operation of the same when conveying material thereby.

Another object of the invention isthe provision of mechanism ofthis character,wherein thefull power of its driver will be utilized to-crush foreign matter presentin the material when conveyed thereby,without'endangering-the power unit or driver, while indestructible foreign matter contained in the material will be automatically ejectedfromthe mechanism, and thereby relieving the driver and adjuncts thereto from disablementtherefrom, and with resultant continuity of operation ofthe mechanism.

A furtherobjectof the invention is the provision of mechanism of this character, wherein the ejected matter can-bereadily and easily removed, and such mechanism does not require constant attendance,as the ejectedmatter need not beremovedimmediately, for the continued operationofthemechanism. Other devices, such as shear pins,-throw-ou-t means,.etc., are presently used to protect such conveyor mechanism, but these require that the impeding object be removed before the-operation-of the conveyor can be resumed, and often, as in the case of stokers, there isno one inconstant attendance, so that inconvenience andsometimes damage results.

A'still further objectof the invention is the provision of mechanism of=this character, which issimple in construction, thoroughly reliable and efficient in operatiomstrong, durable, entirely automatic-in the work-ing'thereof, requiring little or no attention, theparts being readily accessible for repairs or inspection, and inexpensive to manufacture and install.-

With these andother' objects in view the invention consists'in'th-e features of construction, combination and arrangement ofpartsas will be hereinafter more fully" described, illustrated in the accompanying drawingsy-which disclose the 2. preferred embodiment of the invention, and pointed out in the claims hereunto appended.

In the accompanying drawings:

Figure 1 is a fragmentary vertical longitudinal sectional view through a coal stoker showing the mechanism constructed in accordance with the invention installed therewith.

Figure 2- is a sectional view taken on'the line 2--2 of Figure 1- looking' in the direction of the arrows. u H W V H 7 I Figure 3 isa fragmentary side view feed screw and the crusher head inassociated relation to each other, of the mechanisrmthese being on an enlarged scale. J r V Figure 4 is a diagrammatic view of a developed profile of part of'the face along the periphery of the crusher head and helically shaped screw rib ofthe' feed screw'of the mechanism.

Figure' 5 is a detail-side view of the ratchet drive means of the mechanism.

Figure 6'is a view similarto Figure 5 showing the drivemeans in reverse.

Figure (is a plan view thereof.

Figure 8 is a side view of the spreader jaws in spread relation to each other of the drive means.

Figure 9 isa diagrammatic view of the feed control device-for the mechanism.

Figure 10; is a detail elevation of the reverse stop device of the mechanism.

Figure 11 is a detail'elevation ofthe calibrating device for the spreader jaws of the mechanism.

Similar reference characters indicate correspondingparts throughout'the several views in the drawings.

Referring'to the drawings in detail A designates generally a portion of-a coal stoker, and B denotes generally the screw-feed mechanism, respectively, the latter constitutingthe present invention, and hereinafter fully described.

Thestoker A in this instance is shown merely to;illustrate the application and manner of use ofthe mechanism B, as the latter is susceptible of use on other conveyor machines orapparatuses, and comprises a hopper shaped body NJ for containing soft coal oro ther like fuel for stok ing a furnace or other like structure. At the lower smaller-delivery mouth I l of the body I0 is a horizontally; arranged cylindrical or tubular shaped neck I2, which atone end portion I3 extends be yondthe body! 0 into abutting relation to and casting M, the latter having a coupling sleeve formation l5; centrally aligned with the longitu dinal axis of the neck [2, and inconformity with this alignment is a feed screw conduit lawman delivers material from the body Hi to the furnace or the like not shown.

coextensive with the neck l2 and the conduit l5 and working within the same is a rotatable feed screw or worm rib shaft it Working through a clearance therefor in the crusher head l8 removably fitted snugly within the sleeve formation l5 of the stand casting I 4. The crusher head l8 at its face confronting the neck I2 is divided into a number of crushing teeth or projections l9, each of which is helically shaped, so as to approximate extensions of the screw rib 2a! of the screw or shaft so that any object enterin the clearance 2| in the head l8 for the said screw or shaft H, but partly outside of such clearance, will be subjected to direct right-angle shear between the screw rib and one of the teeth or projections l9 for crushing action on the object. This construction prevents any wedging action, and leaves the worm, if stalled by a bolt or other hard object, free to turn backward. This overcomes a common occurrence, that is, objects being tightly wedged between the worm-rib and the entrance to the conduit l6, so that it is difficult to turn the worm or screw backward, and impossible to turn it forward.

The stand casting l4 next to the head If; has created therein below the neck l2 a pit 22 for receiving uncrushed objects from the neck, the communication between these being had by a drop door 23 which is vertically swingable on a hinge 24 and supported in closed position by a lip 25. The hinge 24 is supported in slotted ways 26 so that the door 23 can slide back to clear the lip and fall open, as best seen by dotted lines in Figure 1 of the drawings. A ratchet shaped lug 2'! made from any suitable springy material, is secured to the door 23 at its uppermost side, and is shaped to be depressed by large pieces of coal, etc., which may be dragged over it by the worm rib or screw shaft l1. However, if the worm rib or screw i'l turns backward, the coal in the space between the lug 21 and the head l8 will force the lug 2! together with the door 23 back, and when the door clears the lip 25 the said door will fall open. A. door or removable panel 28 is provided in the side of the casting M for access to the pit 22 so that material may be removed therefrom, and the door 23 reset closed.

At the end of the neck l2 remote from the end portion I3 is a stand casting 29 forming a housing in which is horizontally journaled in any suitable manner a driving shaft 3| having a coupling 32 connected with the screw or shaft designed to resist thrust, or longitudinal movement of the worm in either direction.

In association with the shaft 3| is a ratchet drive mechanism for the shaft l1, and comprises a toothed wheel 33 keyed or otherwise secured to the shaft 3|. A connecting rod 34 is pivoted to a crank 36, which latter is adapted to transmit a reciprocating motion to the ratchet drive mechanism and such crank is formed with an elbow arm 31 carrying the latter back and forth in an are about the shaft 3|. The said mechanism further involves a block 38 which is pivotally mounted on a pin 39 connecting the rod 34 with the arm 37. Within the block 38 are ratchet plungers 40 and 4|, respectively, these being workable in suitable slots in the said block 38, and are urged outward by springs 42. The plunger 40 is the forward ratchet and the plunger 4| is the reverse ratchet, in the operation of the ratchet mechanism.

ill

On the block 38 are closely arranged stud jour nals 43 carrying rollers 44 which fit into notch like seats 45 closely spaced apart from each other and formed in the inner edges of opposed jaws 45, pivoted at 4'! to the arm 31, as best seen in Figure 8 of the drawings. These jaws 46 are forced together by a spring 48 carried on an adjustable coupling pin 49 loosely fitted in the ends of the jaws 46 remote from the pivoted ends thereof. The jaws 46 are spread apart by the rollers 44 passing from one pair of seats 45 to the other pair thereof, as will be apparent from Figures 6 and 7 of the drawings.

Cooperatin with the ratchet mechanism is a feed control device, comprising a segmentalshaped shield wing 50 formed at the periphery of a mutilated gear 5| freely or loosely mounted on the shaft 3|, and this gear meshes with a gear 52 fixed to an axle 53 which is extended outside of the housing 3|), while at the outer end of this axle is a pointer hand 54 having a latching pin 55, which is spring controlled, to engage in holes 55 in a dial area having identification markings 51, and in this manner the hand is held in any selected or desired adjusted position, as will be best seen in Figure 9 of the drawings.

On the plunger 4|] is a striker lug 58 which extends over the shield Wing 5|] and prevents this plunger from engaging in any of the teeth in the wheel 33 as covered by the said shield wing 5|]. By changing the position of the shield wing 50 it will be seen that the amount of material fed by one revolution of the power crank 58 can be varied, or entirely out off. The setting of the shield wing 50 is indicated by the numeral identification markings 51 on the dial area toward which the pointer hand 54 points. It will be noted that there is no lug on the reverse plunger 4|, so that the shield wing 50 does not affect the reverse motion or movement.

On the shaft 3| is a reverse stop device, which includes a collar 59 secured to the said shaft and carrying a pin 60, while next to the collar 59 and freely movable on the shaft is a ratchet wheel 6|, which is free to turn in the normal forward direction of the worm 2|] of the screw ll, but is prevented from turning in the opposite direction by a ratchet dog or pawl 62 which acts as a ratchet in association with the said wheel. The wheel 6| is provided with a radial pin 63, which engages the pin 60. The collar 59 can revolve freely in the direction shown by the arrow in Figure l6 of the drawings, pushing the pin 63 and with it the wheel 6|; but in reverse, the pin 6|! leaves the pin 63 and makes approximately a full revolution before engaging it On the other side, as shown by dotted lines, in said Figure 10, when the mechanism will be stalled by the ratchet dog or pawl 62 acting through the wheel 5| and the pin 63.

In the normal operation, the crank 58 revolved by a power unit, not shown, imparts, through connecting rod 34, a reciprocating motion to the crank 36 carrying the block 38, which latter in the extreme positions are shown in Figure 9 of the drawings. The ratchet plunger 4| will move to the left, sliding over the teeth of the wheel 33 without turning it, but on the swing to the right it will engage the first tooth not covered by the shield wing 50 and revolve the wheel 33 and through it the worm 20, in an are equal to 2, 4 or 6 spaces depending on the setting of the shield wing 50. This cycle is repeated over and over, and this constitutes the normal action of the mechanism.

If a foreign object, for example a bolt, comes amazes between the rib of the worm 20 and the crusher head 19 the worm will be stopped. Then the connecting rod 34 pulling on the pin 39 will force the block 38 to revolve about the said pin 39, moving such block over into reverse position as shown in Figure 6 of the drawings. This change in position is resisted by the pins 44- with the rollers 43 thereon, having to spread the jaws 46 to pass from one position to the other as shown in Figure 8 of the drawings. The amount of resistance is accurately adjusted as hereinafter described.

When the drive is reversed, the ratchet plunger 60 drives the wheel 33 in a counter-clockwise direction, thus turning the worm backward. The pressure of coal against the lug 21 causes the door 23 to move back and fall open, spilling the part of the coal nearest the head it! and with it the impeding object, into the chamber 22. Atapproximately one reverse revolution of the worm, the reverse stop device becomes active, under its construction as before set forth, changing the position of the block 38 to that as shown in Figure 5 of the drawings, and normal operation of the worm is resumed. If it should happen that a second impediment occurs before the chamber 22 is cleaned out and the door reset, it is probable that the impeding object will be worked down into the coal in the said chamber 22 by the repeated back-and-forth movement of the worm, since these objects are usually heavier than coal; but if this does not happen, no damage would result, since the mechanism would change from one position to the other until the impeding object is removed.

To calibrate the resistance in the jaws 46 so that the amount of force required to change the position of the block 38 would be near the safe limit of the motor or power unit, but would not endanger it there has been provided a calibrating device. For example, assume that it has been calculated that the block 38 should move from one position to the other when the torsion about the pin 39 is between 100 and 110 inch-pounds. This calibrating device comprises an arm 64 with a hole 65 to slip over the pin 39 and a pin 66 to engage the hoie 61. On the arm 64 is a weight 98 to slide from one position shown by full lines to that position shown by dotted lines, best seen in Figure 11 of the drawings. It is designed so that the torsion about the pin 39 with the weight 68 in one position is 100 inch-pounds, and with the weight in the other position, 110 inch-pounds.

With the arm 64 in the position and the worm resisted against turning, the pressure exerted by the spring 43 to hold the jaws 46 together is adj usted by turning the nut 69 on the coupling member 49 so that the weighted arm 64 will not turn the block 38 with the weight in the first position, but will render it quicker acting into reverse if the weight is shifted to the second position, but this adjustment can be checked from time to time, after the stoker is in service, so that any change in the elasticity of the spring 48 can be compensated. The exact amount of torsion at which the change should occur can be calculated from the known factors, and it can be readily seen that the motor or power unit will be fully protected, but will use its full power to attempt to crush any impeding object before rejecting it.

What is claimed is:

1. Driving mechanism of the character described comprising a screw conveyor, driving means having a shiftable portion for rotating said screw conveyor in alternate directions, power means for reciprocating said driving means to 6 normally drive said conveyor in a forward direction, and automatic means for shifting said driving means to alternate driving positions when the movement of said conveyor is retarded.

2. A mechanism as described in ciaim 1 including means actuated by the reverse movement of said conveyor to shift said driving means to a forward drive position after limited reverse movement or" the conveyor.

3. Driving mechanism of the character described comprising a screw conveyor, a ratchet drive having a shiftabl'e portion for rotating said conveyor either forward or backward, power means for reciprocating said ratchet drive to normally drive said conveyor in a forward direction, and automatic means for shifting said ratchet drive to alternate driving positions when the movement of said conveyor is retarded.

4. Driving mechanism of the character described comprising a screw conveyor, .a drive wheel for rotating said conveyor, a drive having a shiftable portion for rotating said Wheel in alternate directions, power means for reciprocating said drive to normally rotate said conveyor a forward direction, and automatic means for shifting said drive to alternate-driving positions when the movement of said conveyor is retarded.

5. Driving mechanism of the character described comprising a screw conveyor, a gear wheel for driving said conveyor, a shiftable double acting driving member for rotating said gear wheel in alternate directions, power means for reciprocating said driving member to normally drive said conveyor in a forward direction, and automatic means for shifting said double acting driving member to alternate driving positions when the movement of said conveyor is retarded.

6. Driving mechanism of the character described comprising a screw conveyor, a gear wheel for driving said conveyor, double acting pawls shiftably mounted for alternate driving engagement with said gear wheel for driving the same in alternate directions, power means for reciproeating said pawls to normally drive said conveyor in a forward direction, and automatic means for shifting said pawls to alternate driving positions when the movement of said conveyor is retarded.

7. Driving mechanism of the character described in claim 6 including adjustable means for resisting the shifting movement of said pawls.

8. Driving mechanism of the character described in claim 6 including means actuated by the reverse movement of said conveyor to shift said pawls to a forward driving position after limited reverse movement of said conveyor.

9. Mechanism of the character described comprising a material conveyor, means for moving said conveyor in a forward and backward direction, a crusher head at the forward end of said conveyor, a depository beneath and communicating with said conveyor adjacent said crusher head, a movable cover normally closing said depository, and depressible means cooperating with said cover and disposed in the path of the flow of material moved by said conveyor adapted to move said cover to an open position upon reverse flow of the material.

10. Mechanism of the character described comprising a material conveyor, means for moving said conveyor in a forward and backward direction, a crusher head at the forward end of said conveyor, a depository beneath and communicating with said conveyor adjacent said crusher head, a horizontally movable cover normally closing said depository, and depressible means 00-.

operating with said cover adapted to project into the path of the material upon backward movement of said conveyor whereby said cover is moved to an open position to allow the material to discharge into said depository.

11. Mechanism of the character described comprising a material conveyor, means for moving said conveyor in a forward and backward direction, a crusher head at the forward end of said conveyor, a depository beneath and communieating with said conveyor adjacent said crusher head, a sliding drop door for said depository normally supported in a horizontal closed position, and means associated with said door actuated by the backward flow of material to move said door to an open position and allow the material to discharge into said depository.

12. A mechanism of the character described comprising a screw conveyor, reciprocating driving means having a shiftable portion for rotating said conveyor in alternate directions, power means for reciprocating said driving means to normally drive said conveyor in a forward direction, automatic means for shifting said driving means to alternate driving positions when movement of said conveyor is retarded, a crusher head at the forward end of said conveyor, a depository beneath and communicating with said conveyor adjacent said crusher head, a movable cover normally closing said depository, and depressible means cooperating with said cover and disposed in the path of the flow of material adapted to move said cover to an open position upon reverse flow of the material.

ROBERT N. DULANEY.

REFERENCES CITED The following referenlces are of record in the file of this patent:

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