Brush chipper

[57] ABSTRACT

Apparatus for reducing material such as limbs, branches, brush and the like to chips wherein a reversible powered feed mechanism moves the material in a longitudinal feed path to a statically balanced, rotary chipping mechanism having a chipping disc mounting only a single, generally radially disposed, chipping knife which is angularly disposed relative to the feed path to draw the material forwardly. The apparatus also includes drive mechanism operating the feed mechanism and disc at a correlated rate which considers the angular disposition of the single knife to move material to the disc at an optimum rate causing the knife to reduce the material to chips.

Claims, 5 Drawing Figures

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PATENTED JAN 211975

SHEET 1 OF 3

3,861,602

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PATENTED JAN 211975

SHEET 2 OF 3

3,861.602

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FIG.3

PATENTED®?! 1975

3,861.602

SHEET 3 OF 3

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FIG.5

3,861,602

Another object of the present invention is to provide

BRUSH CHIPPER

BACKGROUND OF THE INVENTION

This invention relates to chippers mounted on portable, wheeled frames which may be drawn behind a 5 truck or the like and which are intended for use by municipalities, for instance, in reducing such material to saleable chips. Chipping machines constructed according to the present invention are particularly adapted to be manually fed. ¹⁰

In prior art drum-type machines the knife drum rotates at a high velocity, i.e. in the neighborhood of 3000 r.p.m., causing the material being chipped to be drawn into the chipping disc at a high feed rate, i.e., 250 to 600 feet per minute. When an individual manually ¹⁵feeds limbs to such a machine, he cannot satisfy this high rate of feed, and thus the machine cannot be operated efficiently. Moreover, the horsepower available in such machines substantially exceeds that required to accommodate manual feeding. Further, if a workman’s clothing, gloves, or the like, become inadvertently caught in the material being fed at the high rate, i.e. in excess of 100 feet per minute, it is difficult for the workman to react sufficiently quickly to avoid being drawn with the clothing into the chipper.

Another safety factor to consider in manually fed chippers is the possibility of “material backfire”. Before the chipping disc commences to cut brush, it sometimes causes the brush to “backfire”, forcing it toward the workman. If the chipping disc is traveling at a very high rate, the material is backfired at a very high rate and may cause serious injury.

Accordingly, it is an object of the present invention to provide apparatus for reducing limbs, brush, and the 35 like to chips, which can be safely, manually fed.

It is another object of the present invention to provide chipping apparatus of the type described which utilizes a feed rate matching the work rate of an ordinary workman and will efficiently operate when being 40 manually fed.

Revolving chipper members which travel at high rotational velocities, i.e. 3000 r.p.m., require dynamic balancing. It is an object of the present invention to provide chipping apparatus which need not be dynamically balanced.

Prior art machines are also known in which chipping discs mount a plurality of circumferentially spaced, radially disposed cutting or chipping knives and include a plurality of radially disposed slots extending axially through the disc to axially pass the chips. Such discs are normally keyed on precision machined drive shafts. Because of the manner in which such prior art shafts and discs are Coupled, the slots and cutting knives cannot intersect the central axis of the chipping disc. Moreover, if the rotational velocity of a multi-blade disc is decreased so that the feed rate at which the material is drawn into the machine matches the manual feed capability of an individual, the knives cut through the wood at such a low speed that they tear and crush the fiber edges of the chips, rather than cleanly cutting the wood into chips. Such crushed chips are unacceptable for many applications and are not saleable for them.

It is a further object of the present invention to provide a rotary cutting disc mounting a single cutting knife having a leading cutting edge which can extend to intersect the rotational axis of the disc.

apparatus of the type described having a rotary chipping disc with a generally radially disposed cutting knife extending along an axial slot which extends through the disc for passing chips cut by the knife.

With apparatus constructed according to the present invention, the disc includes a radially disposed, axial slot intersecting the rotational axis of the disc and a chipping knife having a leading edge extending through the rotational axis, thus permitting a smaller diameter disc to be utilized than has been previously required.

It is still another object of the present invention to provide chipping apparatus of the type described having a vertically inclined chipping disc, a downwardly, forwardly inclined feed chute upstream of the disc, and a feed roll supported above the chute for feeding the material to be chipped in a downwardly, forwardly inclined path of travel to the disc to crowd the material toward the disc. The crowding of material into the chipping disc prevents brush and the like from bouncing back, or “backfiring,” toward the operator, thus resulting in a safer operation.

These, and other objects of the present invention, will become apparent to those of ordinary skill in the art as the description thereof proceeds.

SUMMARY OF THE INVENTION

Apparatus for reducing trees, brush, branches, and. the like to chips wherein material to be chipped is fed toward a chipping disc having a single, generally radially disposed cutting knife thereon, which is rotated at such a speed that material being chipped will be drawn toward the chipping disc at a rate of feed which will match the working feed rate of an ordinary workman.

The present invention may more readily be described by reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view of chipping apparatus constructed according to the present invention, parts of the frame being broken away to more clearly illustrate other portions of the apparatus;

FIG. 2 is a partly sectional, rear elevational view of the chipping apparatus, taken along the line 2—2 of FIG. 1, part of a feed apron for supporting material to be chipped being broken away to more clearly illustrate ⁴³ an overhead feed roll;

FIG. 3 is a rear end view particularly illustrating the chipping disc, taken along the line 3—3 of FIG. 1;

FIG. 4 is a top plan view, taken along the line 4—4 of FIG. 1; and ⁵⁰ FIG. 5 is a schematic diagram of a fluid control circuit for controlling the operation of the apparatus illustrated in FIGS. 1-4.

Apparatus constructed according to the present invention is mounted on a portable frame, generally des⁵⁵ ignated F, supported for movement by groundengaging wheels 10 mounted on a frame supported axle 11, as usual. The frame F includes a hitch (not shown) for attachment to a draft vehicle, such as a tractor or the like. The frame F mounts a chipper housing or cas^J ing, generally designated 12, including a pair of axially spaced, front and rear end walls 14 and 16 spanned by a generally cylindrical side wall 18. A chip discharge spout 20 is mounted atop the wall 18 for directing chips ₆₅ S to a discharge location.

A cutter head or chipper assembly, generally designated 26 and disposed in the chipper housing 12, is mounted on a drive shaft, generally designated 22,

3,861,602 which extends through an opening 14a in the front end wall 14 and is journaled for rotation about an axis a by frame supported bearings 24. The chipper head assembly 26 includes a cylindrical chipper disc 32 having its forward face 32α welded, at 34 (FIG. 3) to the drive shaft 22, and a plurality of equiangularly spaced fan blades 28 welded at 29 to the shaft 22 and to the forward face 32α of the chipper disc 32. It is important to note that the shaft 22 is fixed to the fan blades 28 and to the disc 32 and does not journal the disc 32 or the ¹fan blades 28.

The chipper disc 32 includes a single, radially disposed chip passing slot 36 located substantially equiangularly between a pair of the fan blades 28. The slot 36, which passes axially through the disc 32, extends radially from the periphery of the disc, and terminates a slight distance d radially beyond the rotational axis a of the disc. The weld 34 between the chipping disc 32 and the shaft 22 is interrupted by the slot 36. A radially dis- , posed, axial recess 39 is provided in the chipping disc 32 adjacent the slot 36 and receives a radially disposed wood cutting or chipping knife 40, which is fixed to the disc by a plurality of bolts 42, for cutting brush, trees, branches, and the like, generally designated B, into . chips S that axially pass through the slot 36. The leading edge 40α of the wood cutting knife 40, which is axially upstream or rearward of the upstream or rearward face 32Z&gt; of the cutting disc 32, intersects the rotational axis of the disc 32. The radially inner end of the leading cutting edge 40α projects a small distance d, i.e. onefourth inch, beyond the rotational axis a of the disc 32. The chip size can be varied by varying the width of the cutting knife 40.

The rear end wall 16 of the chipper housing 12 includes an axial opening 27 which, for a 3 foot diameter cutting disc 32, may typically be 16 inches wide and 10 inches high. The lower border surface 27α of the opening 27 is generally horizontal and positioned approximately 1 Ά inches below a horizontal plane p intersecting the rotational chipper disc axis a. As the cutting knife 20 moves downwardly, it will force the material B being chipped against the border surface 27α which acts as an anvil. If the border surface 27α is spaced more than 1 '/a inches above or below a horizontal plane intersecting the axis a, the material B will be thrown sidewisely, either toward or away from the axis a depending on the relative positions of the various parts and the material being chipped.

Apparatus for rotating the cutterhead drive shaft 22 and the cutterhead assembly 26 comprises a belt 43 which is trained around a pulley 44, fixed to the end of the drive shaft 22, and a pulley 46 fixed to the end of a shaft 48 journaled in frame supported bearings 49. The shaft 48 is coupled to a drive shaft 49α via a universal coupling member 52 which is driven by a frame supported, gasoline powered engine, schematically designated 50.

Provided upstream or rearward of the cutter head assembly 26 is a feed assembly, generally designated 54, comprising a pair of axially spaced apart mounting plates 56 (FIGS. 2 and 4), spanned by a pair of side plates 60 and 62. The feed assembly 54 is swingably mounted on a shaft 58 having a rotational axis b positioned at one side of, and extending generally parallel to, the chipping disc axis a. The shaft 58 is journaled by frame supported bearings 61.

A feed roll, generally designated 66, is mounted for rotation on the side plates 60 and 62 by a shaft 68. The feed roll 66 is driven by a gear wheel 70 meshing with a gear wheel 72 fixed to the output shaft 71 of a hydraulic motor 74, carried by one of the frame plates 56. The feed roll 66 includes a cylindrical drum 76 having a plurality of circumferentially spaced, toothed or serrated blades or plates 78 on its periphery. The feed roll 66 is driven in the direction represented by the arrow c (FIG. 1) about the axis x of the shaft 68 to feed limbs, branches, and small diameter trees, all of which are under about ten inches in diameter, brush, and the like, generally designated B, toward the chipper assembly 26. The feed roll 66 is so mounted or extends to a position in which it is positioned on the side of disc axis a opposite axis b and overlies the center o of the branch B being chipped so that it will be generally longitudinally aligned with the opening 27 in the rear housing wall 16. Since the rotational velocity of the chipping knife portion intersecting the disc axis a is zero, this portion of the knife does not effectively cut large diameter material B. It will, however, sever and dislodge small branches which tend to jam in the radially inner portion of opening 27. The material B tends to be urged radially away from the disc axis a to a position between the periphery and rotational axis of disc 32, by the feed roll 66 which is upwardly, outwardly inclined when it is feeding the material B.

The feed assembly 54 also includes a curvilinear chute or support apron 80 for supporting and guiding material B to be chipped for movement, in the direction of the arrow g, toward the chipper disc 32. The apron 80 has a portion 81 adjacent the chipping disc 32 which is forwardly inclined at a 15° angle e to a horizontal plane p and the chipping disc 78 is forwardly inclined at a 30° angle f relative to a vertical plane v. The included angle between the cutting disc 32 and the terminal portion 81 of the chute 80 thus is 60 and the knife edge will accordingly always avoid taking a pcr¹ pendicular cross grain cut.

Counterweights, generally designated 82, are fixed to one of the feed assembly side plates 62 to normally downwardly bias the feed assembly 54 to the position illustrated in FIG. 2 against a pair of stops 86 and 88 ’ mounted on the frame F. If the material B being chipped increases in diameter, the feed assembly 54 automatically rides up over it, pivoting the entire feed assembly 54 upwardly to the chain line position illustrated in FIG. 2. A wall 89 is welded between the pair of fan blades 28 which substantially border chip slot 36 and functions as a static balancing device. It is situated directly axially behind the slot 36 and is of comparable weight to the material removed to form slot 36.

Referring now more particularly to FIG. 5, the control circuit is illustrated and includes a hydraulic pump 90 which is driven by the diesel engine 50 driving the chipping unit 26. The pump 90 is connected in circuit with the hydraulic motor 74 for driving the feed roll 66 of the unit 54. The hydraulic motor 74 may be of the type manufactured by Charllynn Company, of Minneapolis, Minnesota, as Model No. 3000. The pump 90 pumps fluid from a reservoir 92 through a line 93 to a pilot-operated valve, generally designated 94, including a main valve 95 and a pilot valve 96. The valve 94 may be of the type manufactured by Rivett, Inc., of Pewaukee, Wisconsin, as Model No. 6656. When the valve 94 is deenergized, fluid flows from the line 93

3,861,602 through the main valve 95 to a line 97, and then to a reservoir 98. The pilot valve 96 is connected between a reservoir 99 and the pump 90 by a line 100, which is connected to the output of the pump 90. A relief valve 101 is connected between the line 93 and a reservoir 106 for relieving the pressure in line 93 when it builds to a predetermined pressure.

A solenoid 103 for moving the fluid control spool of the pilot valve 96 to the “flow-through” position is connected with a suitable source of power, such as a D.C. battery 131, which causes the spool of the pilot valve 96 to move to the “flow-through” position. When this happens hydraulic fluid will flow from the line 100 through the line 107 to move the control spool of the main valve 95 to the “flow-through” position so that fluid will flow from the line 93 through the hydraulic motor 74 and then to the reservoir 98 through the line 97. A solenoid 110 on the pilot valve 96 is adapted to be connected across the source of power via a switch 133. When energized, the solenoid 110 moves the spool of the pilot valve 96 to the “cross-over” position so that the hydraulic fluid flows from the line 100 through the line 108 to move the main valve 95 to the “cross-over” position. When this happens, fluid from the pump 90 passes through the line 93 and the motor 74, in a reverse direction, to drive the feed roll 66 in the opposite direction. The reversely flowing fluid then passes to the reservoir 98 via a line 93. By selectively connecting the solenoids 103 and 110 in circuit, the feed roll 66 can be selectively operated in the forward or reverse directions. Both the chipper disc 32 and drive roll 66 are directly responsive to the speed of rotation of the diesel engine 50 and thus the speed of rotation of the drive roll 66 is timed with the rotation of the chipper disc 32. If rotation of the disc is halted by a foreign object, the diesel engine 50 will stop, and thus the feed roll 66 will also stop. The feed roll 66 can be manually independently stopped if desired by manually closing the switch 133 to energize the solenoids 103 and 110.

THE OPERATION

Material B to be chipped, such as branches, limbs, brush and the like, are manually fed to the feed wheel 66 which is rotating in the direction of the arrow c to propel it into the rotating chipper disc 32 where it is cut into chips S by the chipping or cutting knife 40. The chips axially pass through the slot 36 into the enclosure defined by the disc 32, the counterweight rear wall 89, and the fan blades 28 bordering the slot 36. The chips S will be discharged radially outwardly through the discharge chute 20 by the fan blades 28, as they pass the chute 20, into the airstream created by the rapidly rotating fan blades 28. The cutting disc 32 and the feed plate 40 are relatively inclined such that the cutting blade 40 will not cut directly cross-grain, but will cut longitudinally forwardly at an inclined angle not normal to the grain to pull the tree trunks B downwardly and forwardly toward the chipper disc 32 as it cuts therethrough. If the butt end of the limb of a tree B is first inserted, the “draw” of the vertically inclined disc 32 alone will cause the machine to be self-feeding. If non-condensed material, such as branches, brush, and the like, constitute the material B to be cut, the feed roll 66 will tend to bunch the material and cram it toward the disc 32. The rotational speed of the disc 32, which has the single elongate cutting edge 40α, is timed to produce a linear material feed rate in the range 20-85 feet per minute. It has been found that in making standard three-fourth inch length chips, approximately 150 horsepower is required to rotate in a 3-foot diameter chipping blade at a rotational velocity of 1,000 r.p.m. so that a 10-inch diameter “green” branch or the like, which is about maximum diameter for the machine, is drawn in at a feed rate of 85 feet per minute. If the chipper disc 32 is driven at 900 r.p.m., an optimum feed rate of 51 feet per minute is achieved, the feed rate reducing proportionately with the r.p.m. If the rotational velocity of the disc is lowered such that a feed rate of 20 feet per minute is achieved, only 50 horsepower is required.

When a jam-up occurs and the disc or wheel 32 is halted or appreciably slowed, the operator can reverse the direction of feed of wheel 66 to back the material sufficiently away from the disc 32 to permit full speed forward feeding movement to again be achieved. The lever operated switch 133 provided for this purpose is shown in FIG. 5 and is connected to valve 94 to accomplish this.

Because the radial wall 89 spanning the set of fan blades 28 axially opposite the slot 36 is of a weight to balance out the material which has been removed to form the slot 36, the disc structure is in axially static balance and wall 89 also is operative to trap chips in view of its position in back of the slot 36.

Finally, because the rotational axis of the feed wheel 66, in operation, is disposed at an angle relative to the edge 27α of the opening 27, when a limb or branch is disposed below it and being fed toward disc 32, the feed wheel 66 tends to crowd the limb or branch being fed radially outwardly relative to the disc axis a and the pivot axis b, to a position in which the branch B is positioned between the periphery and axis of the disc 32, centered in the opening 27. Of course, this camming increases as the diameter of' the limb being fed increases and the angularity of disposition of wheel 66 increases.

It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.