Note: Descriptions are shown in the official language in which they were submitted.
CA 02383651 2002-04-24
WOOD COLLECTION AND REDUCING MACHINE
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention pertains to machines for collecting, reducing,
compacting and
removing wooden materials, and more particularly to drum chippers and
shredders.
II. Description of the Background
Urban removal of wood and debris at the curbside is presently accomplished
using a
number of labor intensive or environmentally unfriendly methods. These methods
include
burning, bundling at curbside with rope or twine, and collection by city crews
using portable
shredders.
Burning, although less used today than years past, results in smoke and
pollutants being
discharged into the air. This method is particularly a problem during days of
high pressure,
which forces smoke to hover at low altitudes and create a nuisance. As a
result, bun:iing has
been banned by law in many communities.
Most urban collection of wood is currently done by bundling twigs and branches
with
rope or twine and setting then at the curbside for collection. The bundles are
collected by crews,
placed in trucks and transported to land fills or compost piles for disposal.
One problem with
bundling is that compliance with proper collection rules is low. Conlpliance
problems typically
arise when people bundle branches in excess of the size or weight designated
by collection
crews. Problems can also arise when people fail to properly tie the bundles.
Bundles that fail to
comply with collection rules are typically left at the curbside by collection
crews and may sit for
weeks thereby becoming an eye sore and a road hazard.
Another method of removing wood debris is with portable high-speed shredders.
To
remove curbside debris, crews hand-feed branches into a shredder. The hand-fed
branches are
quickly reduced and blown into the back of a truck, often with the aid of a
high-power blower
system. Although this method is fairly effective at reducing wood debris, the
method fails in
many other respects. First, the method provides an inefficient use of labor,
as it requires multiple
crewmembers to drive the truck and handle the branches. Secondly, present day
chippers and
CA 02383651 2002-04-24
shredders generate large amounts of noise pollution. Excessive noise pollution
arises from both
the high speed cutting implements and from the high power blower systems.
Noise pollution
also arises from high speed impacting of the cutting implements upon the
material being
shredded.
Present day shredders also are very dangerous. When branches are hand fed into
rotating
high-speed blades, the blades quickly grab and pull the branches. If an
operator fails to pay close
attention to the job at hand, the operator can be pulled into the shredder and
severely injured.
Another hazard arises from flying debris. Flying debris occurs from splintered
wood being
ejected back towards the operator from the high-speed cutting blades. Because
of the dangers
involved in using high-speed portable shredders, the inefficient use of labor,
and the excessive
noise pollution generated, methods of urban wood removal are in need of
improvement.
Therefore, what is needed for effective urban collection of wood debris is a
quieter,
lower-speed shredder that is safer and needs only a single.person to operate.
SUMMARY OF THE INVENTION
The present invention addresses the above mentioned problems and others by
providing a
machine for collecting and shredding wood which includes: a prime carrier; a
debris collector
operatively attached to the prime carrier; a shredder assembly attached to the
prime carrier, the
shredder assembly having a wood input and an output; a storage bin for holding
reduced wood,
the storage bin attached to the prime carrier; and a conveyor disposed between
the output and the
storage bin for moving reduced wood away from the output of the shredder.
In another aspect of the invention, there is provided a machine for collecting
and
shredding wood as described above which further includes a compactor for
receiving wood from
the conveyor and compressing the wood into the storage bin.
In still another aspect of the invention there is provided a tapered drum
shredder for
reducing wood. A preferred drum shredder includes a housing; a tapered cutting
drum rotatably
mounted within the housing; an anvil adjacent to the cutting drum; at least
one cutting blade
disposed about an outer surface of the cutting drum to provide a compound
cutting angle; and a
drive connected to the drum to provide rotation. The cutting drum is
preferably tapered with a
nose or nose end and a back or butt end which forms a cone, frustum or cone
like shape, e.g. a
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CA 02383651 2002-04-24
-r ,
cutting cone. A cutting cone provides a cutting surface with a plurality of
cutting speeds and
variable torque. The cutting drum preferably includes a plurality of cutting
cones connected in
series. The drum shredder preferably includes a plurality of cutting drums.
Preferably the drum shredder has an anvil; a variable torque, rotatable
cutting drum,
which cooperates with the anvil to form an acute cutting angle; at least one
cutting blade
disposed about an outer surface of the cutting drum; and a drive operatively
connected to the
drum for rotation.
In a preferred embodiment, the drum shredder has a gravity feed chute with
substantially
vertical walls and a floor. In another embodiment, the feed chute is
substantially horizontal. In
still another embodiment, the feed chute is a side feed.
In one embodiment of the invention the at least one cutting blade is a
plurality of cutting
blades. In a preferred embodiment of the invention, each cutting cone, or each
section of the
cutting drum, has at least one cutting blade, which may extend along the
length of the associated
cutting cone or section. In another embodiment of the invention, each cutting
blade may be a
removable hammer with a reversible cutting edge.
In a preferred embodiment of the present invention there is provided a drum
shredder
liaving more than one cutting drum rotatably mounted in the shredder. The
drums may share the
same drive and be connected together or alternatively may have separate
drives. In a preferred
embodiment a plurality of cutting drums are mounted side by side. In a more
preferred
embodiment, a plurality of cutting drums are mounted coaxial with one another.
In a most
preferred embodiment the plurality of cutting drums are mounted coaxial with
one another and
fixed nose to nose.
In one aspect of the present invention, there is provided a shredder having a
discharge
assembly adapted to receive at least two major streams of chips having
different discharge
directions and deposit then efficiently into a storage bin, or away from the
shredder assembly. In
a preferred embodiment hereof, the discharge assembly includes a bellyband, a
transition in
communication with the bellyband, and a discharge port in communication with
the transition,
wherein the bellyband conforms to and follows with the cutting cirum for
guiding reduced
material to the transition.
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CA 02383651 2002-04-24
For a more complete understanding of the present invention, reference is now
made to the
accompanying drawings and following detailed description of the preferred
embodiments.
'fhroughout the several figures and views, like symbols refer to like
elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side view of a machine for collecting and shredding wood in
accordance with
the present invention;
Fig. 2 is a side view of a rear portion of a machine for collecting and
shredding wood in
accordance with the present invention;
Fig. 3a is a partial top view of a variable torque shredder;
Fig. 3b is a cross-sectional, partial side view of a variable torque shredder;
Fig. 4 is a partial side view of a variable torque shredder having coaxial
cutting cones in
accordance with a preferred embodiment of the present invention;
Fig. 5 is a partial top view of a variable torque shredder having coaxial
cutting cones in
accordance with a preferred embodiment of the present invention;
Fig. 6 is a partial side view of a variable torque shredder having coaxial
cutting cones in
accordance with a preferred embodiment of the present invention;
Fig. 7 is a side view in perspective of a cutting blade in accordance with a
preferred
embodiment of the present invention;
Fig. 8 is a rear view of a cutting drum with a bellyband in accordance with
the present
invention; and
Fig. 9 is a side view in perspective of' a drum shredder with a discharge
assembly in
accordance with the present invention.
1)ETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now with more particularity and with reference to Fig. 1, generally depicted
therein at 10
is a preferred embodiment of a machine for collecting and shredding wood.
The machine includes a prime carrier 12; a debris collector 14 operatively
attached to the
prime carrier 12; and a shredder assembly 16. The shredder assembly 16 has a
wood input 18
and an output 20. A storage bin 22 for holding reduced or shredded wood is
attached to the
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CA 02383651 2004-12-29
prime carrier 12. A conveyor 24 may be disposed between the output 20 and the
storage bin 22.
The conveyor 24 is for moving reduced wood away from the output 20 of the
shredder assembly
16 to the storage bin 22.
The prime carrier 12 is a motorized vehicle having an engine 26 and an
operator
compartment or cab 28. Preferably the prime carrier has wheels, as opposed to
tracks, to allow
for street travel at posted speeds and for fuel economy. The prime carrier 12
provides support,
mobility and may provide power to heavy accessories, including the shredder
assembly of tlle
present invention and other accessories. The prime carrier 12 may also have a
universal adapter
30 or universal connection, which provides convenient interchangeability of
accessories for varied
uses. The universal adapter is preferably a ledge or flange that mates with a
recess in an accessory
and is strong enough for support. Accessories which may be attached via the
universal adapter 30
and operated by the prime carrier 12 include: a snow blade or a snow blower
for snow removal;
a brush sweeper or rotating brushes for street cleaning; rotating rakes for
leaf collection; lawn
mower for grass cutting, stump grinder, or road grader, etc. Preferably, the
prime carrier 12 is
adapted for interchangeability of the shredding assembly 16, as described
herein, with a leaf
collection system, as described in U.S. Patent No. 6,263,649, erititled "Leaf
Gathering and
Compressing Machine and Method", by Gross et al., which issued July 24, 2001.
The collector 14 is a device for gathering debris, such as wood, brush, twigs,
branches etc,
and delivering the debris to the shredder assembly. As shown, the collector 14
is a movable arm,
such as a knuckle arm, with a grapple. The collector 14 may be controlled
electrically or may be
controlled with hydraulics. The collector 14 is preferably attached at a front
end of the prime
carrier 12 and is preferably operated from within the cab 28. By placing the
collector 14 at or near
the front of the prime carrier, the view of the operator when gathering debris
on the ground or at
curbside can be substantially improved.
The shredder assembly 16 may be any wood reducing, cutting, or shredding
device. The
shredder assembly 16 has an input 18 for feeding wood to a reducing or cutting
element and an
output or discharge 20 for discharging reduced material. Wood reducing,
cutting and shredding
devices are generally known and include both shredder type and chipper type
machines. Suitable
shredder assemblies include disk type chippers, drum type chippers, rotor type
chippers,
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CA 02383651 2004-12-29
shredders, hammer mills, etc. Preferably the shredder asseinbly 16 is a
variable torque, drum
shredder, as described in detail below or shown in Figs. 3a-6 and 8. Examples
of other types of
shredder assemblies that may be adapted for use with the machine 10 of the
present invention and
attached to the prime carrier 12 include those described in: U.S. Pat. Nos.
5,836,528; 6,082,644;
5,469,901; 4,077,450; 5,692,548; 6,032,707; 5,961,057; and 3,436,028.
The shredder assembly 16 preferably has a feed hopper 32 and a low-speed, high-
torque
cutting implement. A low-speed, high-torque cutting implement reduces flying
debris, lowers
noise levels, and improves safety. Preferably the low-speed cutting implement
rotates about a
cutting axis at a speed of less than 1,200 RPM, more preferably at a speed of
less than 700 RPM,
and most preferably at a speed of 400 RPM or less, but preferably at a speed
of 100 RPM or
greater. A shredder assembly with a feed hopper 32 and a low-speed, high-
torque cutting
implement provides an urban debris collection machine with reduced hazards and
noise. For
example, wood may be placed in the hopper where it can be slowly but
continuously shredded as
the prime carrier moves from location to location. Because the loading of the
shredder can be
spaced over intervals, the time between loads allows slower but continuous
grinding between
collection sites. The slower grinding reduces noise levels and flying debris
thereby making the
device more suitable for urban collection than present day high-speed
shredders, which provide
only immediate wood reduction.
The machine 10 may also have a conveyor 24 for transporting reduced wood away
from
the discharge path of the shredder assembly output 20. The conveyor is
disposed between the
output 20 and the storage bin 22. Preferably the universal adapter of the
prime carrier 12 supports
the conveyor 24 so that the conveyor may be used with attachments other than
the shredder
assembly as described above. Preferably the conveyor 24 is a non-blower
conveyor system, such
as a screw, band system, roller system or gravity feed chute, or combination
of the above, all of
which provide transportation of wood chips and debris without the high noise
levels typically
associated with blower or thrower type systems.
Referring now to Fig. 2, depicted therein at 50 is a partial, side view of a
prime carrier
having a shredder assembly output 52, a conveyor 54, a compactor 56 and a
storage bin 58. The
conveyor 54 is preferably a conveyor band. The conveyor band may have
projections or paddles
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CA 02383651 2002-04-24
extending from the band for enhancing material movement in the direction of
band travel. The
conveyor 54 may be in direct communication with the storage bin or may be in
communication
with other devices which can further process the reduced debris, such as the
compactor as
describe below.
Preferably, the machine includes a compactor 56 for compressing debris into
the storage
bin. The compactor 56 may be integral with the conveyor, such as when the
conveyor is a screw;
or the compactor may be a system separate from the conveyor. As the storage
bin 58 fills, the
compactor 56 reduces the volume of incoming material to enhance space
utilization.
Preferably, the compactor is a screw 60 rotatably mounted downstream from the
conveyor 54. As shown, the conveyor 54 is mounted upwardly at an angle to
deliver debris to
the top of the screw 60. By mounting the conveyor 54 upwardly at an angle to
deliver debris to
the top of the screw 60, jamming of debris at the output/conveyor interface or
at the
conveyor/compactor interface can be greatly lessened while at the same time
accentuating spatial
displacement of the system. The screw 60 collects debris and forces it into
the storage bin 58
through an opening 62. Preferably, the debris is forced in at a bottom portion
of the storage bin
58 or at a point below 1/2 the volume height of the container. Preferably, the
opening in the bin
is above the very bottom of the bin and may be adjustable, such that the
opening can be shifted
over a number of locations from the bottom of the bin to about the 1/2 volume
height. By
forcing debris into the bin at a bottom portion thereof, enhanced compaction
utilizing the force of
incoming material against the weight of stored material can be obtained
without jamming the
compactor. If jamming occurs the opening of the feed can be raised to reduce
the amount of
compaction. If the amount of compaction desired is greater, the opening can be
lowered,
towards the bottom of the bin. Hence, compaction can be adjustable.
The storage bin 58 is a container for holding reduced wood and debris. The
storage bin
58 is preferably mounted at a back portion of the prime carrier. Mounting the
storage bin at a
back portion of the prime carrier provides improved operator sight during
collection and
shredding operations, especially at curbside in urban locations. The storage
bin 58 has an
opening 62 for receiving reduced material. The opening 62 is preferably
provided below the 1/2
volume height of the storage bin and above the bottom of the bin as described
above. The
storage bin 58 may also be adapted for dumping or discharging stored material.
Dumping may
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CA 02383651 2002-04-24
be to the rear or at the side opposite curb. As shown, the storage bin is
hinged 64 upon a frame
66 and operatively couple to a series of hydraulics 70 (one of which is
shown). The hydraulics
and hinge provide means for emptying the bin by dumping reduced material and
restoring the bin
to the original position. In practice, the prime carrier is driven to a
curbside location where
removal of wood and/or debris is necessary. From within the cab, an operator
activates the
shredder assembly, conveyor and compactor, then gathers debris from the
curbside using the
collector. The gathered debris is dropped into the shredder input or hopper.
The debris is slowly
reduced and expelled through the output to the conveyor. The conveyor
transports the reduced
rnaterial to the compactor, which in turn moves the material into a lower
section of the storage
bin. As the storage bin fills, the weight of previously stored material
presses against the
incoming material to provide compaction. The prime carrier then drives to the
next collection
site. During travel to the next collection site, wood in the hopper may be
continuously, but
slowly shredded. When desired, such as when the bin is full, the prime carrier
may be driven to
a dumping location and emptied. Wood can also be dumped into a packer truck or
open top
truck at the site to allow the prime carrier to continue operation. Thus, what
has been described is
an method of wood collection and reduction which is suitable for single person
operation along
urban streets and roads with reduced noise and improved safety.
Referring now to Figs. 3a and 3b, therein is generally depicted therein at 100
a variable
torque shredder for reducing wood in accordance with a preferred embodiment of
the present
invention. Fig. 3a is a partial top view and Fig. 3b is a partial cross-
sectional side view. The
shredder 100 has a housing, a drive 122, and a tapered cutting drum 114
supported in the housing
and connected to the drive 122. At least one of cutting blade 116 is disposed
about an outer
surface of the cutting drum 114. The shredder 100 also has an anvil 112, which
preferably
cooperates with the cutting drum 114 to form an acute cutting angle. An acute
cutting angle
provides means for capturing and pulling material into the cutting blade(s).
The shredder 100 also has an input 124 and an output 126 where wood or debris
may be
fed into the input 124, reduced, and expelled through the output 126. The
input 124 may be a
gravity feed chute. The gravity feed chute is preferably a collection hopper
(as shown in Fig. 1)
suitable for holding wood while the cutting drum/blades/anvil slowly reduce
the wood. The
hopper preferably has substantially vertical walls 128, 130. Substantially
vertical walls 128, 130
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CA 02383651 2002-04-24
decrease problems associated with incoming debris bridging over the cutting
drum and
interrupting the shredding process. If a hopper is provided, the anvil 112 and
the cutting drum
114 form at least part of a floor 132 of the hopper where material sits until
it is shredded or
reduced. Hence, the floor 132 separates the shredder input 124 from the output
126.
Alternatively, the input may be a side feed. If a side feed is provided, a
feed roll may be added
to the input to regulate the flow of incoming material to the cutting drum and
reduce debris fly-
back. To increase cutting efficiency, the side feed may have a sloping floor
that angles toward
the cutting blades for improving material delivery to the cutting implernents.
As mentioned briefly above, the anvil 112 preferably cooperates with the
cutting drum to
form an acute cutting angle. The anvil 112 may be connected to the housing or
formed integral
therewith. The anvil 112 is adjacent the cutting drum 114 along a cutting axis
and is separated by
a gap to allow drum rotation. As shown, the anvil 112 is a plate which may be
mounted to the
housing or other support. The anvil 112 acts to regulate chip size and
prohibit large pieces of
debris from passing by the cutting drum without reduction. The cutting drum
rotates about a
center point of rotation. Preferably the anvil 112 is positioned adjacent the
cutting drum below
the center point of drum rotation. Positioning the anvil adjacent the cutting
drum below the
center point of drum rotation provides the acute cutting angle. By having an
acute cutting angle,
a pinch point for pulling material into the cutting blades may be provided
that improves cutting
and reduces the amount of ejected material. In a preferred embodiment, the
anvil may be
translatable or movable. By translating the anvil, the distance between the
anvil and cutting
drum may be adjusted to regulate the size of reduced material.
The anvil is preferably slotless. A slotless anvil reduces the chance of
material becoming
lodged at the anvil / cutting drum interface. Alternatively, the anvil may
have a plurality of slots
or notches to enhance material reduction. The slotted anvil is preferably
matched with a cutting
drum having a plurality of cutting blades that mesh with the slots of the
anvil. In such case, the
slots not only allow a cutting/ripping action but also provide a breaking
action. Thus, the anvil
1.12 may not onlyprovide means for adjusting the size of reduced material but
may also provide
an enhanced reducing mechanism.
The cutting drum has two ends and a middle section. The cutting drum is
preferably a
tapered cylinder. The cutting drum preferably tapers towards the middle
section but may taper at
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CA 02383651 2002-04-24
one end, both ends, or any combination of the above. The cutting drum is
preferably cone or
frustum shaped, diamond shaped in cross section, double diamond shaped in
cross section, or
bow tie shaped in cross section. Diamond shaped, double diamond shaped and bow
tie shaped
drums may be provided by selectively tapering the cutting drum at ends and/or
the middle
section or by combining multiple cone shapes together.
The cutting drum 114 is preferably a cutting cone or includes a cutting cone,
such as a
cone, or frustum, e.g. a cutting cone. The cutting cone has a butt and a nose
or nose end. The
nose is the tapered portion of the cutting cone. The cutting cone provides a
plurality of cutting
radii with increasing torque along the cutting axis. The cutting cone also
provides a plurality of
increasing cutting speeds along the cutting axis.
The cutting drum preferably has a solid outer surface or is solid. The outer
surface
preferably has a plurality of pockets for carrying chips. Each pocket is
preferably associated
with a corresponding cutting implement. In a most preferred embodiment, each
pocket is
disposed prior to the associated cutting implement and extends the same length
at said
implement. Preferably, the cutting drum has a substantially uniform, smooth
outer surface, other
than the cutting blades, associated hardware, and pockets. The outer surface
of the cutting drum
or the cutting drum itself may be solid, or essentially solid, such as a solid
cast alloy, forged
inachine steel, cast iron, etc. Alternatively, the cutting drum may be formed
as a plurality of
concentric disks of narrowing radii, which may also be formed of a solid cast
alloy, forged
inachine steel, cast iron, etc. The concentric disks may have a center hole
adapted to fit upon a
shaft. The disks may be pinned to the shaft to fix them in place. The shaft in
turn can be fixed to
a drive. Forming the cutting drum with a plurality of concentric disks allows
for ease of
manufacture, especially for large cutting drums, which may be heavy and
difficult to otherwise
liandle. The disks may be like a series of dumbbells of different sizes. The
disks may form a
series of steps or may form a gradually tapering surface. A Solid or
essentially solid cutting
drum provides increased stability so that the cone does not fly-apart during
operation and also
provides a flywheel effect with increased momentum so that chipping large
branches does
liamper the cutting blade. The solid cutting drum or the concentric disk-
cutting drum may then
be milled or welded to fix cutting blades in place. The cutting drum may have
a hollow center
CA 02383651 2002-04-24
portion, which may be suitable for fixing a drive shaft therein.
Alternatively, the drum and the
shaft may be a one-piece milled head and shaft.
The cutting drum is connected to a drive 122. The drive 122 provides rotation
and power
to the drum 114. The drive 122 may be a drive shaft connected to a flywheel,
which is powered
by a motor. The cutting drum may be further supported by a stub shaft at an
end opposite the
drive, which is journalled to a bearing for additional support. The stub shaft
may be supported
by the housing. The drive is preferably connected to an inner, tapered portion
136 of the drum.
The drive 122 may be connected to the most tapered portion of the drum, is
preferably connected
within 40% of the most tapered portion, more preferably within 25% of the most
tapered portion,
and most preferably within 10% of the most tapered portion. By connecting the
drive 122 to a
most tapered part of the drum 114, torque can be substantially increased.
The cutting drum has at least one cutting implement or cutting blade.
Preferably, the
cutting drum has a plurality of cutting blades disposed about the outer
surface of the drum. In a
first embodiment of the cutting blades, the cutting blades 116, 118, 120 are
incrementally
staggered about the drum surface to permit the pulling of debris toward a
higher torque-cutting
radius. The pattern may be a reverse screw or screw type pattern. Preferably,
each cutting blade
extends about 50% or less of the possible cutting axis or length of the cone,
and more preferably
extends about less than 20% of length of the cone, and most preferably less
than 10% the length
of the cone. Hence, each cutting blade cuts or impacts along a relatively
small portion of the
drum length (or cutting plane) as opposed to a long, single blade, which
extends the length of the
cutting drum. By having relatively small cutting blades, which do not extend
along the entire
length of the drum, a low speed, high torque cutting drum can be provided with
substantially
reduced jamming and blade breakage during operation.
Referring now to Fig. 7, shown therein at 300 is an embodiment of a preferred
cutting
implement 300 in accordance with the present invention. As shown, the cutting
implement 300
is a hammer. The hammer has a head 302 and a body 304. The body 304 is
preferably
cylindrical and has a depression for er-gaging a setscrew to fix the hammer to
a cutting drum.
T7ie head 302 has a sharpened upper edge 308 for cutting wood. The sharpened
upper edge 308
niay be provided by a plate 310. The plate 310 is preferably square or
rectangular, but may be
any shape that matches a front portion of the head 302. The plate 310 is
preferably rotatable
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CA 02383651 2002-04-24
with a first sharpened edge 312 at the top of the plate and a second sharpened
edge 314 at the
bottom of the plate. A rotatable plate with at least two sharpened edges
allows the first
sharpened edge, which has been dulled by use, to be quickly exchanged with a
second sharper
edge by simply loosening the plate and rotating the first edge out of
position. As shown, the
plate 310 is fixed to the head 302 with a bolt.316 that extends through the
back of the head to
engage and secure the plate in place. The hammer is preferably removably
seated within the
cutting drum and extends above the surface thereof. The hammer may be held in
place by a
setscrew that engages the depression 306 in the body 304.
In a preferred embodiment of the cutting implements, as shown in Figs. 6 and
8, the
cutting blade(s) 508, 510, 512 is (are) a long knife(s) or chisel(s) that
extends longitudinally
along the cutting axis of the cutting drum. Each knife may be connected to the
cutting drum at
an acute angel relative to the surface thereof to enhance chipping and
material draw into the
shredder. Preferably each cutting blade extends at least 50% of the length of
the cutting zone,
rnore preferably extends at least 90%, and most preferably extends
substantially the entire length
of the cutting zone, e.g. the exposed cutting region or section of a cone or
cutting plane, i.e. plus
or minus a few inches.
The drum shredder preferably includes more than one cutting drum, cutting
cone,
diamond shaped cutting drum, double diamond shaped cutting drum, or bow tie
shaped cutting
drum (the shapes being determined by cross-sectional view). When more than one
cutting drum
is provided, the cones can be positioned in a multitude of arrays as shown in
Figs. 3a-6, the
arrays including: in parallel or in series, i.e. one next to the other; one
across from the other; or
both. By adding more than one cutting drum, a larger cutting axis with
increased shredding
efficiency can be obtained.
Referring now to Fig. 4, depicted therein at 138 is a preferred embodiment of
a variable
torque shredder having multiple cutting cones 140, 142 wherein the first cone
140 is mounted
coaxial with the second cone 142. The cones 140, 142 are mounted butt to butt
with each cone
having a cutting region with a different cutting angle. The cones 140, and 142
are preferably
attached to one another, and more preferably butted together. The cones 140,
142 share a drive
144 housed in a drive shaft tube 148 for protecting the shaft. The cones 140,
142 are further
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CA 02383651 2002-04-24
supported by a stub shaft 146, which is journalled to a bearing for support.
The bearing in turn
may be supported by the housing.
Alternatively, as shown in Fig. 5, or additionally, multiple cones or cone
arrangements
may be provided, such as mounted side-by-side. Multiple cones 202, 204 that
are mounted side-
by-side may be powered by the same or separate drives 206, 208. The separate
drives may rotate
the drums in the same direction or in opposite directions as desired. Any void
space around the
drums and not directly contacted by the drums, such as on the floor, may be
filled by an inclined
island 210 or wall. The island 210 preferably tapers at the top and slopes
downward toward the
edge of the anvil to guide material towards the blades.
Referring now to Fig. 6, depicted therein at 150 is a most preferred
embodiment of a
drum shredder, the shredder 150 having multiple cutting cones mounted co-axial
and nose-to-
nose. The shredder 150 includes at least one anvil, two rotatable cuttitig
cones 152, 154 mounted
t:o at least one drive, the cutting cones cooperating with the anvil to
provide compound cutting
angles. Preferably, the anvil is mounted at or below the axis of rotation to
provide an acute
cutting angle. As shown, the cutting cones may be separated by a spacer 155,
such as a short
cirive shaft or rod. Each cutting cone 150, 152 has at least one cutting blade
disposed along an
outer surface of the cutting cone, but may alternatively have two, three or
more cutting blades
each. By adding more cutting blades, the rate at which material is drawn into
the shredder can be
increased. Each cutting blade preferably extends substantially the length of
each respective
cutting region or cone. The blades on each cutting cone may be mounted on the
same cutting
plane as the adjoining cutting cone (as shown in Fig. 6) or the blades inay be
staggered as shown
in Fig. 8.
Referring now to Fig. 8, depicted therein at 500 is a drum shredder having a
cutting drum
506 in accordance with the present invention. 'The cutting drum 506 includes a
pair of frustums
_502, 504 fixed together at their respective nose ends, which in turn forms a
single drum 506 that
tapers at a middle section. Preferably, the drum tapers evenly to the center
so that the drum is
balanced and may cut more uniformly. The angle of the tapering is preferably
adapted to be
Nvide enough to accommodate branches having a desired diameter and is
preferably in proportion
to the feed and the drive. The angle between the frustums is preferably at
least 90 degrees. Each
fiustum or region 502, 504 has at least one cutting blade 508, 510, 512
disposed along an outer
13
CA 02383651 2002-04-24
surface thereof, but may alternatively have two, three or more cutting blades
each. Each cutting
blade preferably extends substantially the length of each respective cutting
region. Each cutting
blade preferably has a pocket 514, 516, 518 associated with it for carrying
chips. The pockets
are preferably disposed in the surface of the drum. The shredder 500
preferably has a bellyband
520 that conforms with the cutting drum 506. The bellyband preferably extends
from the cutting
plan 522 to the bottom most portion 524 of the cutting drum 506.
The drum shredder 500 has a plurality of cutting zones or regions with varying
distances
f'rom the input. A first cutting zone has a speed faster than a second cutting
zone. The second
zone has a higher torque than the first zone. The first zone angles inward
toward the second
zone in the direction of material feed. For example, as two cutting cones meet
nose to nose,
rnaterial will typically contact the outer regions of the cones first, as they
have a greater radius
and are positioned closer to the shredder input. As material is shredded, it
is pulled inward by
the action of the cutting blades and the angle of the cutting cone surface to
a second cutting
region of higher torque. The nose-to-nose arrangement thereby provides
enhanced draw and
improved cutting.
In practice, wood is collected and placed in the feed where it is contacted by
the blades of
the cutting drums. Lighter materials are quickly shredded by the cutting
action of the blades.
The reduced material passes through the gap between the anvil and the drums
and is discharged
through the output. Heavier branches will tend to move progressively along the
incline cutting
cones to a higher torque portion thereof, either by gravity or by the design
of the cutting blades
and the configuration of the cutting cones, or all of the above. The high
torque, slower speed
region of the cutting cones can then be effectively utilized to reduce large
branches, even at a
slower speed.
Referring now to Fig. 9, depicted therein at 400 is a discharge assembly for
allowing
chipped material to be effectively dispelled from the shredder into an
awaiting vehicle or onto
the ground substantially clear of the unit. The discharge assembly 400
includes a bellyband 410
which forms a space that is in communication with the chipping zone 412 or
material/blade
contact plane; a transition 414 in communication with the bellyband 410; and a
discharge port
416 in communication with the transition 414.
14
CA 02383651 2002-04-24
The bellyband 410 is a housing that follows the surface of the cutting drum
418 to guide
reduced material to the transition 414. The bellyband 410 preferably begins
adjacent to the anvil
420 and follows an arc A around the cutting drum 418. The arc A is defined as
beginning where
chipping takes place (the material/blade contact plane), which is defined as 0
degrees. The point
or plane of the arc A directly opposite the cutting point is then defined
herein as 180 degrees.
The bellyband provides a space between the bellyband and the cutting drum for
chips to travel
in. The bellyband may have a front wall and a set of sidewalls. The bellyband
preferably
c:onforms with the shape of the cutting drum. In a preferred embodiment
hereof, where the
cutting drum is tapered, the bellyband is formed with a multi-sided, and/or
multi angled front
wall that conforms to the angle of the tapered drum. For example, if the drum
is 'bow tie'
shaped in cross-section, or tapered toward a middle section, the bellyband
will have a wall with
surface having a'v-shaped' cross-section. The space between the bellyband and
the cutting
clrum is preferably uniform or substantially uniform along the length and
width of the bellyband.
The clearance of the bellyband from the cutting implements is preferably 1/8th
of an inch or less
and more preferably 1/16th of an inch or less. The bellyband preferably
extends along less than
180 degrees, more preferably extends along less than 135 degrees, more
preferably extends along
less than the 120 degrees and more preferably less than 95 degrees of the arc
A. The bellyband
preferably extends along at least 90 degrees of the arc A. In relative terms,
the bellyband
preferably extends to the point (or plane) of the arc that includes the lowest
point of the cutting
drum, but is preferably less than 10 degrees past this point. The bellyband
410 terminates at the
transition 414.
The transition 414 is an enclosed housing that allows chips to be guided away
and
upward from the cutting drum and/or the bellyband to be discharged from the
machine. The
transition begins at a point where the distance from the cutting drum
increases (over that of the
bellyband, which is substantially uniform). The transition 414 ultimately
tapers along a length to
a discharge port (not shown), which may be circular, ovular, square or
rectangular. The
transition 414 may be attached to the bellyband 410 or any other suitable
structure, such as the
housing. The transition 414 preferably guides the direction of chips beginning
as close to the
bottom, most point of the arc of the chipper housing or at the point where the
bellyband ends and
away from the cutting drum. As shown the transition has a series of walls,
including sidewalls, a
CA 02383651 2002-04-24
=
f'ront wall and a rear wall. The sidewalls of the transition are slanted away
from the cutting drum
and may be slanted inward and upward so as to ultimately intersect above and
forward of the
cutting drum. The volume of the space created by the transition is preferably
greater than that of
the bellyband. Attached to the sidewalls may be a frontal wall 424 and rear
wall 422. The
frontal wall begins where the bellyband ends and preferably begins at the
bottom most point of
the cutting drum 418. The frontal wa11424 preferably extends forward and
upward on the same
plane as the sidewalls, gradually tapering so as to intersect at the same
point above and away
from the cutting head as the sidewalls. The rear wall 422 is the wall nearest
the cutting drum.
The rear wall 422 is preferable shaped to conform to the shape of the cutting
drum. The rear
wall preferably forms an extended void directly after the bellyband. The rear
wall is preferably
multi-sided, such as two-sided, circular, three-sided, or more. For example,
in accordance with a
preferred embodiment, i.e. where the cutting drum is tapered toward the center
of the drum, the
rear wall may be 'v shaped' to create a void conforming to the "v" shaped
angle of the cutting
head. The rear wall may be formed by a 2-paneled assembly, tapered upward and
away from the
cutting head to create an entry space with an extended void for chips
discharged from the center
of the tapered cutting drum to enter. The extended void is ultimately enjoined
by the 2 inclined
side-walls and tapered forward to ultimately intersect at an imaginary point
upward and forward
of the cutting drum. The discharge port is preferably provided at a point of
5" to 10" below the
intersection point of the side walls and most preferably about 8"or more below
the intersecting
point of the side, front, and rear walls.
To aid in chip discharge, the cutting drum 418 preferably has at least one fan
blade 432 attached to the side thereof. Preferably, the cutting drum has 3
blades 432, 434, 436
disposed on each outer base (one of which is shown) of the cutting drum to aid
in chip discharge
through the bellyband and into the transition.
In practice wood chips are produced at the cutting zone by cutting knives and
the anvil.
The chips are carried in the space between the bellyband and the cutting drum,
and may be
carried in one or more pockets 424, 426 disposed below each cutting blade 422,
428. The shape
of the bellyband may then act to separate or keep separate the two or more
major chip steams to
enhance forward directional momentum by reducing chip collisions. The chips
exit the space of
the bellyband 410 away from the drum into the transition 416. The extended
void 430 of the
16
____.._ ~. ._ .__ _......,,,..~........_ _ . __.,.~..,,._._- . .. __._._
CA 02383651 2002-04-24
transition allows chips traveling in the center of the chipper to be
efficiently discharged from the
bellyband with reduced chip collisions.
In a taper drum application the reduced material is expelled in at least two
major
discharge streams. The discharge streams also have at least two different
major discharge
directions or angles. By using a bellyband and a transition in accordance with
the present
invention, at least two major discharge directions can be accommodated to
reduce chip collision
and enhance chip discharge through the discharge port.
While the invention has been illustrated in detail in the drawings and the
foregoing
description, the same is to be considered as illustrative and not restrictive
in character. For
example the shredder of the present invention may be adapted for shredding
tires, appliances,
etc, with only slight or no modifications to the invention hereof. Therefore,
it should be
understood that only the preferred embodiments have been shown and described
fully and that all
changes and modifications that come within the spirit and scope of the
invention are desired to
be protected.
17
