US2616592A

US2616592A - Agitating means for wood waste hoppers

Info

Publication number: US2616592A
Application number: US39870A
Authority: US
Inventors: Guy A Boughman
Original assignee: BOUGHMAN MACHINE Co
Current assignee: BOUGHMAN MACHINE Co
Priority date: 1948-07-21
Filing date: 1948-07-21
Publication date: 1952-11-04
Anticipated expiration: 1969-11-04

Description

Nov. 4, 1952 G. A. BOUGHMAN AGITATING MEANS FOR WOOD WASTE HOPPERS 4 Sheets-Sheet 1 Filed July 21, 1948 GUY A. Bouq HMA N.

1 5 ca. A. BOUGHMAN 2,616,592

AGITATING MEANS FOR wooo WASTE HOPPERS Filed July 21, 1948 4 Sheets-Sheet 2 1952 cs. A. BOUGHMAN AGITATING MEANS FOR WOOD WASTE HOPPERS 4 Sheets-Sheet 4 Filed July 21, 1948 Patented Nov. 4, 1952 AGITATING MEANS FOR WOOD WASTE HOPPERS Guy A. Boughman, Lenoir, N. C., assignor to Boughman Machine Company, Lenoir, N. 0., a corporation of North Carolina Application July 21, 1948, Serial No. 39,870

3 Claims.

This invention relates to apparatus for burning finely divided wood particles, such as sawdust or shavings from woodworking machines, or wood chips such as are commonly produced by wood hogs or pulverizers.

This is a continuation in part of my co-pending application Serial Number 709,811, filed November 14, 1946, issued as Patent No. 2,496,146, dated January 31, 1950, and entitled Wood Waste Disposal Apparatus.

The primary object of this invention is to provide an apparatus for conveying divided wood particles to a conventional boiler or furnace with a minimum of conveying medium, such as air, and to cause these particles to essentially burn in suspension thus giving a faster and more efficient combustion than has heretofore been possible.

It is a further object of this invention to provide a storage compartment or bin into which shavings may be directed for storage and being provided with a screw conveyor in the lower portion of the storage bin for conveying and metering the wood particles from within the storage bin to the exterior of the bin and providing a plurality of intermittently rotatable agitators above the screw conveyor which are provided with a reciprocating driving means that will impart a step by step rotation to the agitators and whereby in the event that the wood particles become too closely packed to allow the agitators to move freely, the agitators will exert intermittent or pulsating pressure against the wood particles surrounding them until they have dislodged the material packed therearound or until the screw conveyor therebelow has removed suflicient wood particles to relieve the packed wood particles around the agitators, at which time the agitators will resume their step by step rotation.

From the conveyor, the wood particles are dumped into a funnel disposed on the intake end of a fuel pick-up chamber having suction and blowing means connected thereto, there being a space between the discharge end of the screw conveyor and the funnel to the pick-up chamber so that excess wood particles may fall out over the sides of the funnel without clogging the apparatus, there being no enclosure between the discharge end of the screw conveyor and the funnel to the pick-up chamber. The suction within the fuel pick-up chamber creates an inward air flow into the top of the funnel to thus assist in pulling the wood particles into the fuel pick-up chamber. 1

Itis therefore another object of this invention to provide a space between the discharge end of the screw conveyor and the funnel to thus eliminate a suction or air pressure in the screw conveyor thereby avoiding one of the former causes of wood particles becoming packed in the screw conveyor.

It is still another object of this invention to provide a vane within the fuel pick-up chamber, pivoted at one end, and the free end of which is raised slightly by the moving air from the suction means to which the pick-up chamber is connected to create a narrow opening between the lower edge of the vane and the fuel particles through which air at high velocity must pass to thus cause the fuel particles to be forced into suspension in the air and to be drawn through the suction and blowing means so as to deliver the wood particles to a fire box of a suitable furnace as an air-borne discharge characterized by a high proportion of solids to air. This novel arrangement allows a much higher ratio of fuel to air than usually is possible, or would be possible without it. The above vane is preferably provided with an adjustable weight disposed outside of the fuel pick-up chamber so as to control the ratio of wood particles to air mixture created in the fuel pick-up chamber.

Another object of this invention is to have the suction means connected to the upper side of the pick-up chamber so as to cause the air to be drawn upwardly and to thereby allow objectionable heavy pieces of wood and the like to remain in the duct where they can be easily removed.

It is still another object of this invention to provide a storage bin into which fuel particles are conducted, the storage bin having conveying means disposed therein and means disposed above the conveyor for agitating and breaking up large lumps of fuel particles within the storage bin, said means being adapted to rotate in step by step relation under a certain predetermined pressure, but also being adapted to merely serve as a pulsating means when step by step rotation is retarded to thereby knock large pieces of compressed fuel particles apart so they may be easily carried out of the storage bin by the conveyor, and providing a funnel into which the conveyor delivers the fuel particles, a fuel-air mixing chamber acting in a manner similar to that which a carburetor does with liquid fuel, connecting the funnel to the suction side of a suction and blowing means and the pick-up chamber having a vane having an adjustable weight or loading means associated therewith andclisposed thereon, the suction and blowing 3 means having a discharge pipe extending therefrom to a furnace so that the weight or loading means may be adjusted to permit a predetermined density of wood particles to enter the furnace.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which Figure 1 is a side elevation of the apparatus showing a storage bin and a portion of a furnace adapted to be associated with this invention;

Figure 2 is a top plan view, on an enlarged scale, of the central portion of Figure 1, omitting the storage bin walls and being taken substantially along the line 2-2 in Figure 1;

Figure 3 is a top plan View of the right-hand portion of Figure 1, on an enlarged scale, and being taken substantially along the line 3-3 in Figure 1;

Figure 4 is an enlarged elevation with parts in section, showing the discharge end of the screw conveyor and the means for intermittently rotating the agitating members and being taken along the line Q-: in Figure 1;

Figure 5 is an enlarged elevation of the righthand portion of Figure and is taken substantially along the line 55 in Figure l;

Figure 6 is a sectional plan view taken along the line i3-3 in Figure 4;

Figure 7 is a vertical sectional view on an enlarged scale and is taken along the line 1-1 in Figure 1; I

Figure 8 is an enlarged vertical sectional v1ew taken along the line 8- 3 in Figure 1 and showing the discharge end of the screw conveyor and the duct work associated therewith;

Figure 9 is a vertical sectional view showing the means for adjusting the position of the electric motor relative to the gear box and is taken along the line 9-9 in Figure 1;

Figure 10 is a vertical sectional view taken along the line iii-4& in Figure 1;

Figure 11 is an elevation with parts in section and is taken along the line ll|i in Figure 2;

Figure 12 is a vertical sectional view taken along the line l2i2 in Figure 11.

Referring more specifically to the drawings, the numeral I0 indicates a suitable storage bin which may be of any desired height or width and into which wood particles such as shavings, chips, saw dust, hogged fuel, and the like may be projected by any suitable means such as through a pipe 92 disposed adjacent the upper end of the bin iii. One of the walls of the storage bin it is provided with a suitable opening 13 therein through which a conveyor mechanism may extend and there is disposed above the opening l3 another smaller hole l4 through which an agitator shaft passes.

The conveyor mechanism comprises a semicircular trough 23 having angle bars 2| and 22 secured to each side thereof, by any suitable means such as spot welding, and this trough 29 also has an angle bar 23 extending longitudinally at the lower surface thereof to serve as a support for the trough 2%. This trough 29 is open its entire length above a horizontal plane passing through its longitudinal axis.

Welded to the angle bars 2!, 22 and 23 is a plurality of semi-circular supporting members 24 to thus provide a framework for supporting thetrough 2i Suitable legs are provided, in-

dicated at 26, the lower ends of which rest on the floor of the bin and the upper ends of which are welded to the longitudinally extending

angle bars

21 and 22.

The right-hand end of the trough 20, as observed in Figures 1 and 3, is closed by a plate 39 which is secured to the right-hand ends of the angle bars 2i and 22 and the left-hand or discharge end of the trough 23 has a plate 3| which is secured to the left-hand ends of the angle bars 2! and 22, as observed in Figures 1 and 2. The semicircular trough 20 does not extend the full length of the longitudinally extending angle bars 2! and 22, so as to leave an opening 40 at the discharge and of the conveyor so that the wood particles such as shavings and the like may be discharged through the opening i!) into a suitable funnel to be later described. Welded to the vertical plate 3! adjacent the opening 48 at the discharge end of the screw conveyor 3'! are projections .39 for breaking packed chips and other wood shavings and the like after they may have been compacted by movement through the screw conveyor 3'5. The wood particles indicated at 9 are omitted from all parts shown in the accompanying drawings except the duct means to be later described, for purposes of clarity.

The plates 33 and 31 have bearing blocks 33 and 34, respectively, secured thereto, by any suitable means such as screws 35. Extending Ion-- gitudinally of the semicircular trough 20 is a screw conveyor 31, having a shaft 38, the righthand end of which is rotatably mounted in the bearing block 33 and the other end of which is rotatably mounted in the bearing block 3 1. It will be noted that the screw conveyor 3'! is spaced substantially from the trough 29 to prevent packing of wood particles at that point.

The conveyor shaft 38 extends outwardly beyond the bearing block adjacent the discharge end of the conveyor, and has an eccentric cam wheel fixedly mounted thereon, the function of which will be later described.

Fixedly mounted adjacent the cam wheel $5 is one half of a sprocket wheel and sprocket chain coupling 4?, the other half of which is fixedly mounted on a stub shaft extending from a conventional speed reducer 5|. Obviously, other overload release coupling means may be used to connect the speed reducer 5| to the conveyor shaft 38.

The speed reducer 51 is fixedly mounted, by any suitable means such as screws 52, on a plate 53 welded to and spanning the distance between the angle bars 54 and 55. The angle bars 54 and 55 have bridging transverse angle bars 56 welded to each end thereof (Figure 2) and the ends of the angle bars 54 and 55 are supported by legs 5'! and 58, the lower ends of which are adapted to be secured to the floor of the buildmg.

The legs 51 and 58 have angle bars 60 extending from the lower ends thereof and these angle bars are spanned by a narrow plate 6| which is threadably penetrated by a vertically disposed bolt 82. The bolt 62 extends upwardly and loosely penetrates a pivot member 53 which is vertically adjustable on the bolt 62 by lock nuts 64 and 65 threadably mounted on the bolt 62. The pivot member 63 has stub shafts 61 integral therewith, the outer ends of which are pivotally mounted in bearing portions 68 of a motor base plate i9.

By referring to Figure 1, it may be observed 5 c that the motor base plate I extends to the left at an angle and is hingedly mounted, as at", on the vertical legs 58. This motor base plate it has a suitable electric motor 73 secured thereon by any suitable means such as screws I4 and this electric motor it has electric wires 75 and it extending therefrom to a suitable source of electrical energy, not shown.

The electric motor I3 has a shaft 11 extending therefrom on which a suitable expansion pulley comprising a fixed pulley 80 and a slidable pulley BI is mounted (Figure 10). y

This slidable pulley 8! is urged toward the fixed pulley 89 by a compression spring 82, the compression of which may be adjusted by a cap 83 disposed at the other end of the'compression spring and being threadably mounted'on the end of the shaft 'Il. This expansion pulley has a V- belt t extending upwardly therefrom which engages a pulley 86 fixedly mounted on a shaft 31 extending outwardly from the speed reducer 5| at right angles to the stub shaft 50.

It is thus seen that by lowering or raising the free end of the motor base plate 70, the tension of the belt 35 will be increased or decreased, as desired, and in the event that the free end of the plate "50 is lowered, the additional tension placed on the V-belt 05 will cause the V-belt 85 to move the slidable pulley 0! on the shaft 1'! away from the fixed pulley 00 to thereby change the ratio of speed between the pulley 86 disposed on the shaft thereabove and the expandible pulleys 80 and BI.

The plate 35 extends upwardly above and beyond the trough shaped member 2e and is rigidly supported on brace members H5 (Figure 1), the upper ends of which are secured, by any suitable means such as screws H8, adjacent the upper end of the plate 3! and the lower ends of which are secured, by any suitable means such as screws Ill, to longitudinally extending angle bars H0, the left-hand ends of which are welded to the vertical plate 3|, in Figure 1, and the right-hand ends of which are welded to one of the intermediate semicircular supporting members 24 which extend upwardly above the side rails 2! and 22.

It will be noted that the angle bars H8, the plate 3! and the associated supporting member 24, adjacent the discharge end of the screw con- I veyor 31, define an enlarged area above the discharge opening 443 and through the wall of the storage bin It to minimize any possibility of the wood particles choking up the opening It in the wall of the bin It.

Disposed above the screw conveyor 31 is an agitator shaft 90, which is rotatably mounted in bearing blocks E25 and I26, the bearing block I25 being secured in the upper end of the vertically disposed plate 3!, by any suitable means such as screws I 21 and the bearing block G20 being secured in the upper end of the plate 30, by any suitable means such as screws I30 (Figure 1).

The upper end of the plate 30 is rigidly supported by brace bars I32, the upper ends of which are secured adjacent the upper end of the plate 30 and the lower ends of which are secured to the longitudinally extending angle bars 2| and 22. Fixedly mounted on the shaft 90 is a plurality of agitator members I35, comprising a transverse plate I36 having agitator vanes I31 extending from opposite sides thereof and at opposite angles relative to each other, each of these vanes being triangular in shape and having small radius I40 at their outer ends.

By referring to Figure 4 it may be observed that the eccentric cam wheel 45 is adapted to engage a roller 95 which is rotatably mounted on a transverse stub shaft 9s fixedly mounted in a substantially U-shaped bracket 91. The U shaped bracket QI is threadably mounted on one end of a horizontally disposed shaft I00, the other end of which is slidably mounted in an externally threaded bearing screw IIlI. This bearing screw i0! is threadably mounted in a plate I02 welded between the outer ends of substantially L-shaped spaced plates I03 and I04 (Figures 4, 5 and 6). The L-shaped plates I03 and I04 have elongated slots H35 and I05, respectively, which are penetrated by the shaft 96 so that the shaft 96 may have horizontal sliding movement in the slots I 05 and I06. The plate I02 has a plate I01 welded to its uppermost surface and extending to the right in Figure 4. The plate I0! is threadably penetrated by a set screw I08 which is adapted to engage the bearing screw I01 to lock the same in adjustment against a compression spring to be presently described.

Surrounding the shaft I00 and engaging the U-shaped member 9'! at one end and the screw IOI at the other end, is a compression spring I I 0, the pressure of which may be adjusted against the U-shaped member 9'! by the adjustment screw IOI. The shaft I00 is prevented from being moved out of the bearing screw I 01 by the spring H0, by means of a retaining pin I09 which is pressed into the outer end of the shaft I00 and projects outwardly at opposite sides thereof and engages the bearing screw IN.

The L-shaped plates I03 and I04 are also held in spaced relation to each other by a plate member H2. The L-shaped members I03 and I04 are pivotally sup-ported at a point intermediate their vertical legs on a restricted portion H4 of a stub shaft H5 which extends rearwardly, or to the right in Figure 1, and is secured, by any suitable means such as welding to the vertically disposed plate 3|.

The spaced L-shaped plates I63 and I04 extend upwardly beyond the pivot point II 4 and have a stub shaft I20 (Figure 4) fixedly mounted therein, and bridging the distance therebetween. This stub shaft I20 has oscillatably mounted thereon a ratchet pawl I2I. The ratchet pawl IZI has an outwardly extending arm I22 integral therewith from which a weight member I23 depends. The ratchet pawl I2I is adapted to engage a ratchet wheel I26! fixedly mounted on the shaft and it is thus seen that rotation of the screw conveyor shaft 38 on which the cam wheel 45 is fixedly mounted will transmit step by step rotation to the shaft 90.

It is thus seen that by step by step rotation of the shaft 90, in the manner heretofore described, the agitator vanes i3! will agitate the wood particles within the bin I0 to thus stir up the wood particles and prevent their caking up and forming a cavity therein so there will always be an ample supply of the wood particles delivered to the screw conveyor 3'1.

Now, in the event that the wood particles become so tightly packed around the agitator vanes E3? as to retard rotation of the same, and the shaft 90, this would ordinarily place a heavy load on the driving means associated with the conveyor 3?. Whenever rotation of the shaft 90 is retarded in this manner, rotation of the eccentric cam wheel may continue without imparting a complete stroke to the upper end of the L-shaped plates I03 and Hi l in the manner to be presently described.

The eccentricity of the cam wheel 45 is taken up by the compression spring I I through the roller 95 engaging the periphery of the cam wheel "55 and the compression spring IIG will continue to take up this eccentricity of the cam wheel 45 until free rotation of the shaft 99 is allowed.

Although rotation of the eccentric cam wheel 55 cannot impart a full stroke to the L-shaped members Hi3 and EM, at each revolution, every time the roller 95 causes the compression spring H0 to compress, this will also cause the upper end of the L-shaped members I03 and I05 to be urged to the left in Figure l until the resistance of the compression spring H0 becomes equal to the resistance to pressure against the vanes 31, at which time the complete stroke will then be resumed with each rotation of the cam wheel 65. In the event that the resistance of the compression spring H0 is so great that it creates an undue strain on the vanes I31 of the agitator $35, the adjustment screw I0! may be loosened so the agitator I55 will not be caused to rotate until the resistance of the packed wood particles has become lessened by the screw conveyor 3? carrying away the wood particles.

Conversely, if the agitator members I31 do not rotate when the consistency of the material around them is lighter than it is believed necessary by the operator, then the adjustment screw IIiI may be tightened to increase the pressure of the compression spring IIO to thereby cause the shaft 90 to continue to rotate in step by step rotation until the vanes I31 are placed under a heavier pressure or greater resistance by the wood particles within the storage bin It. Disposed below the opening 46 at the discharge end of the conveyor 31 and on the outside of the bin I 0 is a funnel I50 (Figures 1, 4 and 8) which empties into a rectangular tube or duct Iiii comprising a fuel pick-up chamber, which has a vane I52 disposed therein. The funnel I50 is spaced below the discharge end of the screw conveyor 31 so a suction within the duct I5I will not cause the wood particles to become too solidly packed at the discharge end of the conveyor I50 and also to permit excess wood particles to spill over the edges of the funnel to prevent the funnel from becoming choked up. Also, this prevents a vacuum in the wood particles bin and. thus maintains proper metering of the fuel particles discharged from the fuel pick-up chamber.

The vane I52 is fixedly mounted at one end on a rod I554 pivotally mounted in the vertical side wall of the duct I5I. The rod I54 on which the vane I52 is mounted extends outwardly from one side of the duct I5I and is bent at right angles to form an arm I55 parallel to the side edge of the vane I52 and on which an adjustable weight member I56 is secured (Figure 4) by any suitable means such as a set screw I51. This vane I52 determines the volume of wood particles to be delivered through the duct I55, increases the proportion of wood particles to air pulled through the duct, by means to be later described, and acts as a check valve, as will also be later described.

The rectangular tube or duct I5I has an opening I60 therein which is closed by a suitable cap closure I6! which may be opened, if so desired, to clean or inspect the interior of the rectangular tube I5I.

Rising upwardly from that end of the duct I5I which is remote frOm the funnel I50, is a pipe I63 (Figure 11) which extends to a suction blower broadly designated at I10 (Figure 12) and which has an opening I1I at one side thereof for the reception of the wood particles from the pipe I63. This opening III is surrounded by the pipe I63 which is fixedly secured to the housing I10. The blower housing I10 has a shaft I12 therein on which radially disposed blades I13 are secured and the outer edges of these blades I13 define a circle when the blades I13 rotate.

The blower I10 has a discharge pipe I14 extending upwardly therefrom and from the junction point of the discharge pipe and the blower housing the radius of the blower housing is slightly more than that of the circle formed by the blades I13 for approximately 65 degrees. From this point on around the blower housing I10 in a clockwise direction in Figure 12 until the housing again meets the discharge pipe I14, the radius of the housing gradually increases to gradually leave more space between the ends of the blades I13 and the interior of the blower housing I10.

The primary advantage of using a blower having this gradual increase in area, as heretofore described, is to create a greater turbulence of the air and shavings brought into the blower housing I10 through the opening I1I as the blades rotate in a clockwise direction in Figure 12 and to thus prevent the wood particles from becoming caked within the blower housing I10.

The discharge pipe I14 rises upwardly from the blower housing I10 and leads to a suitable furnace I having a fire box I3I with grates i82 therein. The discharge end of the blower pipe I14 is substantially larger in diameter than the conveyor pipe I14, preferably about twice the diameter of the conveyor pipe I14, so as to cause the wood particles and the blast of air created by the blower I10 to decrease in velocity as the wood particles enter the fire box I8 I. This allows the wood particles to be more evenly distributed in the burning chamber so as to allow combustion of a major part of the fuel particles while they are in suspension and also prevents a strong blast on the wood particles disposed within the fire box IBI.

In the event of a sudden explosion or blowback from within the fire box I8I of the furnace I80 to where the flames from the burning wood waste would enter the discharge end of the discharge pipe I14, or, at least, a blast of air would be forced back through the duct I14 and into the duct I5I, instead of this blast of air or the flames going on through this duct I5I and blowing upwardly through the funnel I50, the blowback would force the vane I52 within the duct I5I to close downwardly at its free end to thus prevent the blast of air from passing beyond the vane I52 to thus overcome a probable fire hazard as well as preventing the wood particles Within the duct I5I from being blown upwardly through the funnel I50.

The shaft I12, on which the blower blades I13 are fixedly mounted, extends out of the blower housing H0 at the side opposite to the opening HI and is rotatably mounted in bearing blocks itfi (Figures 2 and 11) secured to the upper surface of a motor support base I80, by any suitable means such as screws I81. This shaft I12 has a pulley I fixedly mounted on the outer ends thereof which has belts I94 mounted thereon and these belts I94 extend downwardly to another pulley I95 fixedly mounted on a shaft I96 extending from an electric motor I91.

The electric motor I9'I is adjustably mounted on the vertical wall of the motor mount base I85, by any suitable means such as screws I98, and this electric motor I9I has wires 200 and 20I extending therefrom to a suitable source of electrical energy, not shown.

Now, the screw conveyor feeds the wood particles through the opening 40 into the funnel I50 and the wood particles then fall by gravity into the fuel pick-up chamber II. It may be observed in Figure 8 that the wood particles 49 store up on the right-hand side of the vane I52, which is fixedly mounted on the rod I511. The weight I56 is adjusted on the arm I55 so that the movement of air created by the blower I10 will raise the free end of the vane I52 slightly so as to maintain-a small opening between the bottom edged the vane and the top of the woodparticles 49.

It will be noted in Figure 8 that the movement of air created by the blower blades I13 must move inwardly through the funnel I50 and into the duct I5I and, consequently, the air must pass beneath the lower free edge of the vane I52 and this causes a valley indicated at 49a across the upper surface of the wood particles 49 where the wood particles are mixed with the air drawn by the blower I'II] at a predetermined consistent density throughout the operation of the blower.

It is thus seen that the main function of the vane I52 is to concentrate a particularly high velocity of air at the free end of the vane so the air passing under the free end of the vane will carry with it a much higher percentage of wood particles than would be possible by simply allowing the wood particles to pass through the duct I5I without the use of a vane.

When it is desired to increase the amount of wood particles proportionate to the amount of air drawn into the blower I10, the weight member I56 is moved downwardly away from the pivot point of the vane I52, in Figure 4, and when it is desired to decrease the amount of wood particles relative to the amount of air drawn into the blower ITO, the weight member I56 is adjusted upwardly toward the pivot point of the vane I52.

In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only, and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. An apparatus for conveying shavings and other wood waste from a storage bin, a horizontally disposed trough disposed in the bin and having one end thereof projecting to the exterior of the bin, said trough having its bottom cut away at the point where it projects to the exterior of the bin, a screw conveyor disposed in the trough for moving the shavings from the storage bin to fall through the cut away portion of the trough, means for driving the screw conveyor, agitator means disposed above the conveyor within the storage bin, means driven by the screw conveyor for intermittently imparting step by step rotation to the agitator means disposed thereabove, said agitator means comprising an agitator shaft having a plurality of agitator blades mounted thereon within the storage bin, a ratchet wheel mounted on one end of the agitator shaft and disposed outside the storage bin, a cam wheel mounted on one end of the screw conveyor and also being disposed outside the storage bin, 9'.

pair of spaced L-shaped members pivoted intermediate their ends, acam follower disposed between the ends of the'horizontal legs of the L- shaped members and adapted to be engaged by the cam wheel, spring means for urging the cam follower toward the cam wheel and being disposed between the horizontal legs of the L-shaped members, a ratchet pawl pivotally mounted between the upper ends of the L-shaped members and being adapted to engage the ratchet wheel on the agitator shaft, whereby rotation of the screw conveyor will impart rotation to the cam wheel to in turn impart step by step rotation to the ratchet wheel and to the agitator blades in normaloperation' and whereby when the shavings around the agitator blades create excessive resistance to the rotation of the agitator blades, said spring means will take up a part of the stroke transmitted from the cam wheel to the ratchet wheel through the cam follower, the L- shaped members, and the ratchet pawl.

2. Apparatus for handling wood fuel particles, comp-rising a storage bin into which the wood fuel particles are discharged, a trough disposed in the lower portion of the bin and extending to the exterior of the bin and having a hole in its bottom outside the bin through which the wood fuel particles may fall, a screw conveyor mounted in the trough and also extending to the exterior of the bin, means for imparting rotation to the screw conveyor, a rotary shaft disposed above and in alignment with the screw conveyor and having a plurality of angularly disposed blades thereon, means connecting the screw conveyor with the rotary shaft disposed thereabove for imparting rotation to the rotary shaft, said means connecting the screw conveyor with the rotary shaft comprising a ratchet wheel mounted on the rotary shaft and an oscillatable lever having a dog on its upper end for engaging the ratchet wheel and cam means on the screw conveyor for engaging the lower portion of the oscillatable member for imparting oscillation thereto to move the rotary shaft in step by step relation upon each revolution of the screw conveyor, resilient means mounted in the lower end of the oscillatable member for engaging the cam on the screw conveyor for imparting intermittent motion to the rotary shaft and whereby upon the striking of an obstruction or compacted mass of wood fuel particles by the blades on the rotary shaft, the resilient means will allow rotation of the screw conveyor without imparting undue strain on the rotary shaft and the blades carried thereby.

3. In an apparatus for handling wood shavings comprising a storage bin and having means for agitating the shavings in the storage bin, and conveyor means disposed below the means for agitating the shavings for withdrawing the shaving from the storage bin, means for imparting resilient step by step rotation to the means for agitating the shavings, the combination of said means for agitating the shavings comprising an agitator shaft having a plurality of agitator blades mounted thereon within the storage bin, a ratchet wheel mounted on one end of the agitator shaft and disposed outside the storage bin, a cam wheel mounted on one end of the screw conveyor and also being disposed outside the storage bin, a pair of spaced L-shaped members pivoted intermediate their ends, a cam follower disposed between the ends of the horizontal legs of the L-shaped members and adapted to be engaged by the cam wheel, spring means for 11 urging the cam follower toward the cam wheel and being disposed between the horizontal legs of the L-shaped members, a ratchet pawl pivotally mounted between the upper ends of the L- shaped members and being adapted to engage the ratchet wheel on the agitator shaft, whereby rotation of the screw conveyor will impart rotation to the cam wheel to in turn impart step by step rotation to the ratchet wheel and to the agitator blade in normal operation and whereby when the shavings around the agitator blades create excessive resistance to the rotation of the agitator blades, said spring means will take up a part of the stroke transmitted from the cam wheel to the ratchet wheel through the cam follower, the L-shaped members, and the ratchet pawl.

GUY A. BOUGHMAN.

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

UNITED STATES PATENTS Number Name Date 246,921 Tenant Sept. 13, 1881 374,539 Jones Dec. 6, 1887 603,076 Day Apr. 26, 1898 603,077 Day Apr. 26, 1898 730,934 Leary June 16, 1903 765,832 Hamilton July 26, 1904 1,209,790 Woodcock Dec. 26, 1916 1,583,008 Rand May 4, 1926 1,668,324 Kreisinger May 1, 1928 1,794,326 Sierer Feb. 24, 1931 2,478,079 Beasley Aug. 2, 1949 2,511,514 Rosselot June 13, 1950