Earth working – Lawn aerator or perforator – or plug remover
Reexamination Certificate
2000-02-14
2002-11-26
Novosad, Christopher J. (Department: 3671)
Earth working
Lawn aerator or perforator, or plug remover
C172S123000, C172S542000, C172S545000, C172S550000, C172S553000
Reexamination Certificate
active
06484811
ABSTRACT:
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 of Related 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. Pat. No. 5,813,792 herein incorporated by reference in its entirety.
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 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.
4
A. The main difference is that the cutting hammer
26
′ is double-ended and includes first and second cutting elements
32
A and
32
B. Thus, when one of the cutting elements
32
A is spent, one or both of the end plates
22
(
FIG. 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
32
A, rather than the spent cutting element
32
B, 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
32
B (as well as the cutting element
32
A) 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
32
B results in excessive frictional contact with 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 cutting assembly 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 support rod 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.
According to yet another preferred embodiment of the present invention, a 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 to the first and second support element halves, respectively.
These and other aspects of the invention will be described in or apparent from the following detailed description of preferred embodiments.
REFERENCES:
patent: 502301 (1893-08-01), Kime
patent: 1196954 (1916-09-01), Huebsch
patent: 1362409 (1920-12-01), Forker
pa
Edwards John W.
Novosad Christopher J.
Oliff & Berridg,e PLC
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