Note: Descriptions are shown in the official language in which they were submitted.
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1MPROVEMENTS FOR MULCHING UNIT
FOR USE IN MULCHING APPARATUS
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to an industrial mulching apparatus for use in mulching
vegetation such as brush, trees, etc., or stump grinding. In particular, this
invention
relates to improvements to a mulching unit including a plurality of cutting
assemblies
that serially engage and mulch the intended vegetation in rapid fashion.
2. Description gRelated Art
Figs. 1-4C show a related art mulching apparatus 10. The mulching
apparatus 10 includes a tractor 12 supported on a set of wheels 14. The
tractor driver
can sit within a protected cage 16 positioned on a frame of the mulching
apparatus 10.
A hydraulic unit 18 connected to the tractor 12 provides a means by which a
mulching
unit 20 is positioned, e.g., laterally shifted, raised and lowered. The
tractor 12 is
commercially available from Barco, a manufacturer of tractors. Also, many
details of
the mulching apparatus 10 shown in Fig. 1 are described in U.S. Patent No.
5,813,792
which may be referred to for further details.
The tractor 12 is provided with one or more power sources, e.g., motors,
sufficient to drive the tractor at a desired speed and to rotate the mulching
unit 20 in
the direction of arrow A. The mulching unit 20 can rotate at a speed of about
1,700
rpm, for example. The mulching unit 20 includes a plurality of cutting
assemblies or
hammers 26 that are axially spaced along the length of the mulching unit 20. A
plurality of spacers 27 are provided between each of the cutting hammers 26.
The
spacers 27 define sector shaped portions in which each of the hammers 26
pivots over
a limited range. Movement within the sector shaped portion is in addition to
the
overall rotation of the mulching unit 20 in the direction of arrow A shown in
Fig. 1.
Centrifugal force causes each of the cutting hammers 26 to pivot radially
beyond the
limits of each spacer 27 to thereby engage brush, trees or other vegetation.
Fig. 2 is an enlarged view of the mulching unit 20. The cutting hammers 26
alternate with the spacers 27, and the hammers 26 pivot within each sector
shaped
portion defined by the spacers 27. The hammers 26 in one row are staggered
with
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respect to the hammers 26 in adjacent rows to obtain a substantially
continuous
cutting profile.
Fig. 3 schematically shows the mulching unit 20 to include a pair of end
plates 22 and a plurality of support rods 24. Each support rod 24 includes a
plurality
of cutting hammers 26. For example, each support rod 24 holds 10 to 12 cutting
hammers 26. The cutting hammers 26 are freely rotatable about the support rods
24,
and are sometimes referred to as "flail" mulchers or mowers.
Fig. 4A shows an enlarged view of the cutting hammer 26. In Fig. 4A, the
cutting hammer 26 includes a through hole 28 defining an inner support surface
that is
slidably and rotatably mounted on one of the support rods 24 shown in Fig. 3.
The
through hole 28 is partly defined by a collar 30 on which a cutting element 32
is
formed. In operation, a distal end portion of the cutting element 32 wears
away or
erodes due to repetitive high speed impact with vegetation, the ground, etc.
As such,
it is necessary to replace the cutting element 32, which also requires
replacement of
the collar 30 since it is formed in one piece with the cutting element 32.
Generally,
this is done by disassembling one or both of the end plates 22 from the
support
rods 24, as shown in Fig. 3, and then sliding the collar 30 until the cutting
hammer 26
disengages with the support rod 24. In this manner, one or more of the spent
cutting
hammers 26 can be replaced with new cutting hammers 26.
Fig. 4B shows another example of a related art cutting hammer 26' that is
similar to the cutting hammer 26 shown in Fig. 4A. The main difference is that
the
cutting hammer 26' is double-ended and includes first and second cutting
elements 32A and 32B. Thus, when one of the cutting elements 32A is spent, one
or
both of the end plates 22 (Figure 3) can be detached from the support rods 24,
and the
cutting hammer 26' can be removed from the support rod 24 and reassembled in
an
opposite orientation such that the fresh or unspent cutting element 32A,
rather than the
spent cutting element 32B, engages with the intended vegetation. Otherwise,
the
cutting hammers 26 and 26' are identical in operation.
Fig. 4C is representative of a right side elevation view of either of the
cutting
hammers 26 or 26'. The cutting elements 32 and 32B (as well as the cutting
element 32A) are generally flat and blade-like and are roughly equal in width
to the
width of the collars 30, 30'. This is disadvantageous because the flat and
blade-like
shape of the cutting elements 32 and 32B results in excessive frictional
contact with
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the intended vegetation or the ground during the mulching operation. In
particular,
any dirt or other debris that comes in contact with the blade member must be
directed
completely around each cutting element 30 or 32', which causes undue strain on
the
motor or power source of the tractor 12.
Another disadvantage with the related art structure shown in Fig. 1 is that
the
mulching unit can become misaligned if the mulching unit impacts various
obstacles
during operation. For example, the assembly of the end plates 22 and support
rods 24
may not sufficiently resist deformation when impacting obstacles during the
mulching
operation.
Another related art mulching apparatus includes a rotatable drum having
bullet-like cutting elements fixedly attached to the outer surface of the
drum. These
cutting elements are made from tungsten or carbide and are commonly used in
asphalt
grinding machines. However, deformation of the drum unit is problematic
because it
has a relatively fragile structure not well suited to resisting impact.
SUMMARY OF THE INVENTION
One aspect of the invention relates to providing a mulching apparatus
including a mulching unit and/or cutting assembly with improved cutting
efficiency
and cost-effectiveness for labor and/or replacement parts. Another aspect of
the
invention relates to retrofitting mulching units of the related art with a new
and
improved cutting assembly that improves cutting efficiency and cost-
effectiveness for
labor and/or replacement parts. Another aspect of the invention concerns
reducing the
amount of labor required to replace spent parts.
According to one preferred embodiment of the present invention, a mulching
apparatus comprises a tractor and a mulching unit coupled to and receiving
power
from the tractor. The mulching unit includes at least one cutting hammer
having a
rotatable support element and at least two cutting elements spaced apart from
one
another to define a predetermined gap. The cutting elements may be welded or
otherwise attached to the support element, or they may be formed in one piece
with
the support element.
According to another preferred embodiment of the present invention, a
mulching apparatus comprises a tractor and a mulching unit coupled to and
receiving
power from the tractor. The mulching unit includes at least one cutting hammer
having a rotatable support element and at least one cutting element releasably
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mounted on the support element. The support element may include a base member
and a cutting element holder member integrally formed with the base member.
The at
least one cutting element may include a shank having a first end including a
first
shaped cutting tip and a second end, opposite the first end, having a
fastener. The
fastener may be a quick release mechanism for facilitating removal of the at
least one
cutting element from the support element.
Preferred embodiments of the invention include several different mulching
units. One version of the mulching unit may include a plurality of rows of
support
rods, and the cutting hammer on one of the support rods may be offset or
staggered
from the cutting hammer on another one of the support rods. Another version of
the
mulching unit includes a rotating tube assembly having an outer tube member
and an
inner tube member. The inner tube member is coupled to a drive shaft of the
mulching unit, and the outer tube member includes at least one cutting
assembly, the
cutting assembly including a support element fixedly connected to the outer
tube
member and at least one cutting element freely supported on and movable with
respect to the support element.
The cutting element or elements may take on a number of different
configurations according to preferred embodiments of the present invention,
some of
which configurations have already been mentioned. The shaped cutting tip of a
cutting element may have many different shapes configured according to the
particular cutting needs. For example, the shaped cutting tip may be tapered,
symmetrical, square or triangular in cross-section. The shaped cutting tip may
be
made from tungsten, carbide or another suitably hard material that is
resistant to wear
and abrasion. First and second ends of a cutting element may include first and
second
shaped cutting tips, which may or may not have the same shape.
According to another preferred embodiment of the present invention, a cutting
hammer for use with a mulching unit of a mulching apparatus comprises a
support
element having a collar defining an inner surface rotatably and slidably
mounted to a
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support rod of the mulching unit, and at least first and second cutting
elements
provided on the collar and being spaced apart from one another by a
predetermined
gap.
According to yet another preferred embodiment of the present invention, a
5 cutting hammer for use with a mulching unit comprises a support element
having first
and second support element halves independently rotatable on a support rod of
the
mulching unit, and first and second cutting elements provided on the first and
second
support element halves, respectively.
According to an aspect of the present invention, there is provided a mulching
apparatus comprising a tractor and a mulching unit coupled to and receiving
power
from the tractor, the mulching unit including at least one cutting assembly
having a
freely rotatable support element and at least one cutting element releasably
mounted to
the support element.
According to another aspect of the present invention, there is provided a
cutting
assembly for use with a mulching unit of a mulching apparatus, comprising a
support
element having a collar defining an inner surface rotatably and slidably
mounted to a
support rod of the mulching unit, and a cutting element holder member
integrally
formed with the collar, the holder niember including at least first and second
through
holes and at least first and second cutting elements releasably mounted within
the first
and second through holes, respectively.
According to another aspect of the present invention, there is provided a
mulching apparatus comprising a tractor having a power source and a mulching
unit in
communication with the power source, the mulching unit including a rotating
tube
assembly having inner and outer tube members, the inner tube member being
connected to a drive shaft of the power source and the outer tube member
including at
least one cutting assembly, the cutting assembly including a support element
fixedly
connected to the outer tube member and at least one cutting element freely
supported
on the support element so as to be movable with respect to the support
element.
According to another aspect of the present invention, there is provided a
cutting
assembly for use with a mulching unit comprising a support element having a
collar
defining an inner surface rotatably and slidably mounted to a support rod of
the
mulching unit and at least first and second cutting elements extending away
from the
collar and being spaced apart by a predetermined distance to define a gap
therebetween.
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According to another aspect of the present invention, there is provided a
cutting
hammer for use with a mulching unit of a mulching apparatus, comprising a
support
element having a collar defining an inner surface freely rotatably and
slidably mounted
to a support rod of the mulching unit, the support rod being offset from an
axis of
rotation of the mulching unit; and at least first and second cutting elements
provided to
the collar and being spaced apart from one another by a predetermined gap.
These and other aspects of the invention will be described in or apparent from
the following detailed description of preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will be described in
conjunction
with the following drawings, in which like reference numbers refer to like
parts, and
wherein:
Fig. 1 illustrates a mulching apparatus according to the related art;
Fig. 2 is an enlarged view of the mulching unit shown in Fig. 1;
Fig. 3 is a schematic view of the mulching unit shown in Fig. 1 and 2;
Fig. 4A shows a first embodiment of a cutting hammer according to the related
art;
Fig. 4B shows a second embodiment of a cutting hammer according to the
related art;
Fig. 4C shows a right side elevation view of the cutting hammer shown in
Figs. 4A or 4B;
Fig. 5 shows a cutting assembly according to a preferred embodiment of the
present invention;
Fig. 6 is a left side elevation view of the cutting assembly shown in Fig. 5;
Fig. 7 illustrates the support element shown in Fig. 5, without the cutting
element;
Fig. 8 is a top elevation view of the support element shown in Fig. 7;
Fig. 8A illustrates an alternative preferred embodiment of a support element
according to the present invention;
Fig. 9A illustrates a cutting element and fastener according to a preferred
embodiment of the present invention;
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Fig. 9B illustrates a cutting element and fastener according to another
preferred embodiment of the present invention;
Fig. 9C illustrates yet another preferred embodiment of a cutting element and
fastener according to the present invention;
Figs. 10-12 illustrate yet another preferred embodiment of a mulching unit
according to the present invention; and
Figs. 13-17 illustrate other preferred embodiments of cutting elements
according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Figs. 5 and 6 illustrate a cutting assembly or hammer 50 including a support
element 100 and a cutting element 200. Figs. 7, 8 and 8A illustrate the
support
element 100 without the cutting element, and Figs. 9A-9C illustrate various
embodiments of the cutting element 200, 200', 200" without the support
element.
With reference to Fig. 5, the support element 100 includes a base member in
the form of a collar 102 that defines a through hole having an inner support
surface 104. The inner support surface 104 is slidably and rotatably mounted
one of a
plurality of support rods 24 (shown in Fig. 3). Approximately 10 to 12 support
elements 100 (weighing 8-10 lbs. each) are provided on each support rod 24.
The
collar 102 is integrally coupled to a cutting element holder member 106. The
collar 102 and holder member 106 may be welded together, or they may be cast
of
molten metal in a single mold and formed as a single piece. The holder member
106
includes at least one through hole 108.
As shown in Fig. 6, for example, the holder member 106 includes two through
holes 108. Each through hole 108 is intended to releasably and/or rotatably
receive
one of the cutting elements 200. A gap G is formed between two cutting
members 204 of the cutting elements 200. Each cutting member 204 includes a
shaped cutting tip 207. The gap G is beneficial because it allows dirt and
other debris
to flow between the cutting elements 200, as distinguished from the blade like
cutting
hammer 26 shown in related art Figs. 4A-4C. It is also beneficial to allow the
cutting
elements 200 to rotate within the through holes 108 to further facilitate
movement of
the debris past and between the cutting members 204. The cutting assembly 50
allows
a 30% reduction in the amount of time required for mulching vegetation, e.g.,
large
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trees having a diameter of 24"-36" or larger, as compared to the cutting
blades 26 of
the related art.
Each cutting element 200 includes a shaft 202 defining first and second ends.
The first end of the shaft 202 includes the shaped cutting tip 207, which is
preferably
made of a hard material such as tungsten and/or carbide which is resistant to
abrasion
and frictional contact. The shaped cutting tip 207 should also be resistant to
impact as
well. A second end of the shaft 200 includes a fastening element, such as a
nut 206,
that is threaded onto a threaded portion 202A of the shaft 202 (Fig. 9A). It
is not
necessary to thread the entire length of the shaft 202-a portion 202B of the
shaft 202
may remain smooth and unthreaded, as shown in Fig. 9A. The cutting element 200
is
releasably mounted to the support element and therefore can be easily replaced
without requiring replacement of the support element 100 or undue labor.
Fig. 7 illustrates the support element 100 shown in Fig. 5, but the cutting
element has been removed for clarity of illustration. Fig. 8 is a top
elevation view of
the support element 100 of Fig. 7.
Fig. 8A is an alternative preferred embodiment of a support element 100'
according to another preferred embodiment of the invention. In Fig. 8A, the
support
element 100' includes first and second through holes 108A and 108B. The
through
hole 108A is offset from the through hole 108B such that the a cutting element
positioned within the through hole 108A contacts the vegetation slightly
before the
cutting element positioned within the through hole 108B contacts the same
vegetation.
In this manner, energy drain to the power source of the tractor can be
stepwise
applied, which reduces shock to the energy source. Thus, the mulching unit 20
can
run smoothly and with less interruption required to power up to the proper
rpm.
Fig. 9A shows the cutting element 200 shown in Figs. 5 and 6. In Fig. 9A, the
nut 206 is threadably attached to the threaded portion 202A of the shaft 202
of the
cutting element 200. In an arrangement not shown, a standard bolt can be used
if the
cutting member 204 is suitably threaded. To reduce the possibility of the nut
206
becoming detached from the threaded portion 202 during high speed operation,
it is
also possible to additionally tack weld the nut 206 onto the shaft 202.
Alternatively,
the nut 206 can be replaced with a locking nut or a locking pin arrangement,
so that
the cutting elements 200 can be easily replaced. The cutting element 200 shown
in
Fig. 9A is the type commercially available for use in an asphalt grinding
machine.
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Fig. 9B shows an alternative embodiment of a cutting element 200' according
to the present invention. The cutting element 200' shown in Fig. 9B is similar
to the
cutting element shown in Fig. 9A, but includes a square ended shaped cutting
tip 207'
that is particularly useful for cutting vegetation. The cutting tip could also
have other
polygonal or symmetrical cross sections, such as triangles, hexagons, etc.
Fig. 9C shows yet another embodiment of the present invention. The cutting
element 200" includes first and second shaped cutting tips 207A and 207B. The
first
shaped cutting tip 207A may be similar to the shaped cutting tip 207 shown in
Fig. 9A, while the second shaped cutting tip 207B may be similar to the shaped
cutting tip 207' shown in Fig. 9B. The second shaped cutting tip 207B may
include a
threaded assembly (not shown) which is threaded onto the shank 202", like the
nut 206 or 206' in Figs. 9A and 9B, respectively, or an alternative fastening
mechanism can be used, such as a quick release mechanism that facilitates
removal or
reversal of the cutting element 200". For example, the second shaped cutting
tip 207B may include a blind bore 205 that can receive the shaft 202". When a
hole 206A on the shaped cutting tip 207B aligns with a hole 206B formed on the
shank 202", a separate pin member 209 can be inserted into both holes 206A
and 206B, thus forming a mechanical lock. Additionally, the holes 206A and
206B
can also coincide with another hole (not shown) formed in the holder member
106,
106' of the support element 100, 100'. Also, although different shaped cutting
tips are
shown in Fig. 9C, the shaped cutting tips 207A and 207B may also be identical.
The use of the cutting elements 200, 200' or 200", especially if used in
conjunction with the support element 100' of Fig. 8A, can enable significant
improvements in cutting speed as well as the ability to cut large trees up to
24"-36" in
diameter or larger.
Figs. 10-12 show an altemative embodiment of a mulching unit 20'. The
mulching unit 20' includes a rotating tube assembly 40 including an inner tube
member 42 and an outer tube member 44. The inner tube member 42 passes through
a series of bracing rings 46 connecting the inner and outer tube members 42
and 44.
The bracing rings 46 help improve the structural integrity of the mulching
unit 20'.
The relationship between the inner and outer tube members 42 and 44 and the
bracing
rings 46 is shown in Fig. 11, which is a cross-sectional view along section XI-
XI of
Fig. 10. A shaft 48 is supplied with power from a power source for the
mulching
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unit 20'. A bushing 54 is interposed between the shaft 48 and at least the
outermost
bracing rings 46.
The outer tube member 44 includes a plurality of rows of cutting
assemblies 50'. In the example shown, each row includes about 12 cutting
assemblies 50'. In addition, although not shown in Fig. 10, the cutting
elements in
one row are staggered from the cutting elements in the adjacent rows so that a
substantially continuous cutting profile can be formed as the mulching unit
20' is
rotated.
Each cutting assembly 50' is fixedly mounted on an outer surface of the outer
tube member 44. As such, each cutting assembly 50' is not mounted on a support
rod 24, as shown in Fig. 3. Rather, the support element 100' includes a base
member
in the form of a substantially flat or slightly curved plate member 101 that
is fixedly
mounted onto the outer surface of the outer tube member 44. The plate member
101
can be welded or otherwise bolted to the outer tube member 44. In Fig. 12, the
cutting
elements are not shown for clarity, but can be similar to those shown in Figs.
9A-9C
and Figs. 13-17, described below. Although the through holes 108" are shown as
being uniformly spaced from the outer surface of the outer tube member 44,
they also
may be offset in the manner shown in Fig. 8A.
The structure shown in Figs. 10-12 is advantageous since there is no
requirement to form a collar or to assemble the collar onto the support rod
24, as in
the embodiments of Figs. 5-8A. Also, like the earlier described embodiments,
it is not
necessary to remove the base member (plate member 101) from the mulching unit
20'
to replace the cutting elements. The double walled tube assembly 40 also
improves
resistance to warping or bending when the mulching unit 20' encounters
obstacles that
tend to bend or otherwise warp the mulching unit 20'.
Figs. 13-17 illustrate other preferred embodiments of cutting assemblies
according to the present invention. Figs. 13-15 illustrate a cutting hammer 80
having
a collar 84 with a through hole 88 and cutting elements 82A and 82B. The
cutting
hammer 80 is similar to the cutting hammer 26' shown in Figs. 4B and 4C.
However,
the cutting hammer 80 includes a cutout portion defined by a backwall 86 and
sidewalls S (Figs. 14 and 15). In contrast with the embodiments of Figs. 5-9C,
the
embodiments of Figs. 13-17 do not require a separate holder member 106 and/or
the
additional assembly steps for cutting elements 204. However, a gap G in Figs.
13-15
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serves the same purpose as the gap G shown in Fig. 6, and therefore will not
be
explained further. In Fig. 14, the gap G appears to be fairly shallow, whereas
Fig. 15
is a cross-sectional view of Fig. 13 and shows the sidewalls S as having a
depth that is
fairly significant.
5 Fig. 15A shows representative modifications of the cross-sectional view
shown in Fig. 15. For example, the cutting hammer in Fig. 15A may include
cutting
tips Tl-T4 having various shapes and dimensions. For example, cutting tip T1
may
have a substantially conical shape, whereas cutting tip T2 may have a
substantially
annular shape in cross section, with appropriate spacing between adjacent tips
along
10 the circumference of the collar. The cutting tip T2 may also have a first
wall that is
coplanar with the side surface of the cutting hammer and a second wall that is
angled
with respect to the first wall. Moreover, the cutting tips Tl and T2 may be
molded or
cast as a one piece unit with the collar and remaining elements of the cutting
hammer.
Furthermore, the cutting tips T1 and T2 can be coated with a layer L of
protective
material, such as tungsten and/or carbide. The layer L may also be formed in
the
region between the cutting tips T 1 and T2.
Cutting tips T3 and T4 are similar to those shown in Figs. 9A-9C. The
cuttings tips T3 and T4 have shapes that are selected depending on the type of
vegetation to be mulched and/or mowed. In addition, the cutting tips T3 and T4
can
be attached to the main body of the cutting hammer by any conventional
fashion, such
as by welding, gluing, screwing, mechanical lock, etc. It is to be understood
that all
of the cutting tips for any one cutting hammer preferably have the same shape,
but
that Fig. 15A shows a single cutting hammer having four different cutting tips
for
illustrative purposes. However, cutting tips, e.g., cutting tips T3 and T4,
can be
combined in various fashions if the type of vegetation involved proves to be
more
efficiently cut using a combination of different types of cutting tips rather
than a
single type of cutting tip.
Figs. 15B and 15C show further preferred embodiments of cutting hammers
according to the present invention. Figs. 15B and 15C are cross-sectional
views
similar to those shown in Figs. 15 and 15A.
Fig. 15B shows a cutting hammer 300 having cutting tips 302 that are spaced
apart to define a predetermined gap G therebetween. Each cutting tip 302 is
formed to
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have a triangular or tapered shape, as shown. However, cutting tips 306 may
have a
generally rectangular cross section, as shown.
Moreover, the cutting tips 302, 306 are mounted on support elements halves
304 that are independently rotatable with respect to one another. The total
thickness
of the combined support element halves 304 is roughly the same as the
thickness of
the support element shown in Fig. 15. Also, the support element halves 304 may
be
rotatably fastened to one another using a rotary coupling member (not shown)
that
allows the support element halves 304 to rotate with respect to one another as
well as
on a support rod, e.g., support rod 24 (Fig. 3).
Fig. 15C shows a cutting hammer 400 having cutting tips 402, 404 and 406,
with gaps G formed between tips 402 and 404 and tips 404 and 406. The tip 404
may
be larger than the tips 402 and 406. The tips 402, 404, 406 have a
substantially
triangular or tapered shaped, as shown. Further, rather than a series of three
tips, the
cutting assembly may employ a single cutting tip 408 that has a substantially
tapered
or triangular shape.
Figs. 16, 16A and 17 show additional embodiments of other preferred cutting
hammers according to the present invention. For example, Figs. 16 and 16A show
a
cutting hammer 95 including cutting elements 96 that include a cutout portion
defined
in part by a backwall 98 and sidewalls S, shown in Fig. 16A, which is a side
elevation
view of Fig. 16. The dimensions, shape and orientation of the backwall 98 can
be
determined based on experimental testing. The primary difference between the
cutting hammer 95 in Figs. 16 and 16A and the cutting hammer 80 in Figs. 13-15
resides in the size and shape of the cutting elements 96 versus the shape of
the cutting
elements 82A and 82B in Figs. 13-15. In addition, Fig. 17 shows a cutting
hammer 90 including cutting elements 92 that are spaced apart a predetermined
amount to form a gap (not shown) defined in part by backwall 94. In contrast
with the
cutting hammer 95 of Fig. 16, the cutting hammer 90 of Fig. 17 only includes a
single
row of cutting elements rather than two rows of cutting elements. Further,
other
features described in combination with other embodiments can be used in
connection
with the embodiments of Figs. 13-17. For example, the cutting tips/elements
can be
structured to contact a cutting surface in stepwise fashion, as described in
conjunction
with Fig. 8A.
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While the invention has been described in conjunction with preferred
embodiments thereof, it is evident that many alternatives, modifications and
variations
may be apparent to those skilled in the art. For example, while the cutting
assemblies
according to the preferred embodiments described are shown to include two
cutting
elements, the present invention also contemplates cutting assemblies including
a
single removable or non-removable cutting element. In addition, while the
shafts of
the cutting elements preferably include a circular cross section, which allows
rotation
of the cutting elements within the holder members of the support elements, the
shafts
may also be of a non-circular cross section that allows the cutting elements
to
reciprocate but not rotate. Accordingly, preferred embodiments of the
invention as set
forth herein are intended to be illustrative, not limiting. Various changes
may be
made without departing from the spirit and scope of the preferred illustrated
embodiments.
