Note: Descriptions are shown in the official language in which they were submitted.
CUT'I'ING ELEMENT FOR SOLID WASTE COMMINUTOR
This inventio]l relates generally to solid waste
comminutors and more particularly to an improved cutting
element therefor.
Various apparatus are known for the comminution
of solid waste material into minute particles. One such
comminuting apparatus is described in U.S. Patent No.
4,046,324 issued to Chambers, the inventor herein, and
includes a comminution chamber within which is located a first
and a second shreading stack. Each shreading stack includes a
shaft that carries a plurality of laminar cutting elements
which are separated in an axial direction by a plurality of
laminar spacers. The shreading stacks are disposed within
the comminution chamber such that the cutting elements of a
first stack are in an interspaced relationship with the cutting
elements of the second stack to thereby perform the comminution
function.
The cutting elements of the above-described apparatus
are generally configured in the form of a disc from which
a plurality of teeth radially project. Each tooth has a
first and a second concave surface which lie along an axis
generally parallel to the central axis of the cutting
element. Although these cutting elements may accomplish
the comminution of solid materials whether or not the
materials are entrained in a liquid, it has been
- 1-
found that in the absence of liquid, particles resulting
from the comminution of solid dry material frequently
become entrapped by the concave surfaces of the cutting
element teeth. This build up of material dulls the
cutting surfaces associated with the cutting elements
and may cause the teeth to be broken from the cutting
element, thus decreasing the efficiency and effectiveness
of the apparatus.
Another cutting element that is known for use in
10 comminuting apparatus is disclosed in U.S. Patent No.
3,664,592 to Schweigert et al. The cutting element there
described includes a single filleted or beveled tooth
having a cutting edge which lies in a plane perpendicular
to the axis of the cutting element for shearing the
material introduced into the apparatus. The tooth,
however, is not self-cleaning and thus the cutting
element must also include a back tooth which combs the
free space between adjacent cutting elements to help
remove granulated material therefrom. Additionally, this
20 cutting element is effective only for operation in a
single direction of rotation and thus may not be reversed
to prolong its useful life.
The cutting element of the present invention over-
comes the limitations described above and provides a
cutting element having self-cleaning teeth which are
effective for the comminution of dry solid materials and
which further result in a substantially more efficient
operation of the comminuting apparatus. Accordingly, the
cutting element of the present invention includes a
30 generally disc-shaped body portion which is adapted to
receive the shaft of a comminuting apparatus. Projecting
from the body portion are a plurality of teeth members
which each include oppositely facing lateral cutting
edges and a filleted portion including concave surfaces
connecting the cutting edges and the body portion. The
lateral cutting edges define a cutting path coaxial with
the body portion and the concave surfaces are angled with
respect to this cutting path. The lateral cutting edges
and the curve of the concave surfaces cooperate to cut or
10 slice the material introduced into the apparatus into
generally tightly formed curls or balls producing rela-
tively uniformly sized particles. The angled concave
surfaces then discharge the particles thus created to
the side of the cutting element and thus prevent the
particles from accumulating or packing into the filleted
portions. The cutting edges are similarly angled with
respect to the cutting path, both features resulting in a
more efficient comminution of solid materials and thereby
increasing the operating efficiency of the comminuting
20 apparatus by approximately 70%.
It is thus an object of the present invention
to provide an improved cutting element for a comminuting
apparatus.
It is another object of the present invention
to provide a substantially self-cleaning cutting element
for use in a comminuting apparatus.
It is yet a further object of the present invention
to provide a more efficient cutting element that may be
used in a comminuting apparatus.
~ ~s~
These objects as well as other objects and advan-
tages of the present invention will become apparent
through a consideration of the following detailed
description when taken in conjunction with the accompany
ing drawings.
Figure 1 is a plan view of a cutting element accord-
ing to the present invention.
Figure 2 is a side view of the cutting element taken
substantially along the line 2-2 of Figure 1.
With reference now to the drawings, a cutting
element 10 includes a generally disc-shaped body portion
12. Formed centrally within the body portion 12 is a
hexagonal-shaped opening 14 that is adapted to receive a
shaft of a comminuting apparatus such as the shaft of the
shreading stack previously described. The hexagonal
opening 14 is formed coaxially with a central axis 16 of
the body portion 12.
Projecting from the body portion 12 are a plurality
of teeth members 18. Although the cutting element 10 of
20 Figs. 1 and 2 includes three teeth members 18a-c, it will
be understood by those who are skilled in the art that
the number of teeth members 18 may be varied but prefer-
ably a minimum of two teeth members are provided. It
will be further understood that the number of teeth
members is determined according to several factors,
including the material to be introduced into the appa-
ratus, the fineness of the resulting particles, and the
power and gear reduction employed by the apparatus.
Each of the teeth members 18a-c includes a fille~ed
30 portion 20 extending from the body portion 12, the
filleted portion 20 defining a peripheral surface 22.
The peripheral surface 22 of each of the teeth members 18
in turn defines a portion of a cylindrical surface which
is coaxial with the central axis 16 of the body portion
1~.
The filleted portion 20 further includes a first
and a second concave surface 24 and 26 which smoothly
join the outer surface of the body portion 12 and which
intersect the peripheral surface 22 to define first and
10 second cutting edges 28 and 30.
The cutting edges 28 and 30 lie generally along
a portion of a circular helix that is coaxial with the
axis 15 and which is inclined preferably approximately 30
degrees therefrom. The concave surfaces 24 and 26 are
generally parallel to the cutting edges 28 and 30.
Although this helical relationship is described here to
provide a complete and detailed description of Figs. 1
and 2, it is to be noted that this particular relation-
ship is not critical to the present invention. Thus the
20 cutting edges 28 and 30 may be generally considered to
define a cutting path designated 32 in Fig. 1 and 2. The
cutting path 32 is coaxial with the axis 16 and the
concave surfaces 24 and 26 and the cutting edges 28 and
30 are angled approximately thirty degrees from a posi-
tion across the path and parallel to the axis 16. The
thirty degree angle is to be considered exemplary and
variations therefrom will provide the benefits associated
with the cutting element of the present invention.
It will be recognized by those skilled in the
30 art that the thickness of the cutting element 10 may be
varied along with the number of teeth members 18 to vary
the particle size. Thus the cutting element 10 thickness
may be decreased or increased to correspondingly decrease
or increase the resulting particle size.
In use, a pl~rality of the cutting elements 10 may,
for example, be installed in the comminuting apparatus
described in Patent No. 4,046,324 and may be rotated
about the central axis 16. If the cutting element 10
were rotated clockwise with respect to Figure 1, the
10 cutting edge 30 of each of the teeth members 18 will cut
or slice generally tightly wound curl- or ball-shaped
particles from the material introduced into the apparatus
and these particles will be in turn deflected or guided
away from the cutting element 10 by the concave surface
26 of each of the teeth members 18 into the area provided
between adjacent cutting elements 10 by the previously
described laminar spacers. Once the cutting edge 30 of
each of the teeth members 18 has dulled or has otherwise
become inoperative, the cutting element 10 may then be
20 reversed and the cutting edge 28 and the concave surface
24 will then cooperate as just described.
While an exemplary embodiment of the invention
has been described, it is to be understood that the
invention is not limited to the details herein described.
It is expected that those skilled in the art will recog-
nize numerous variations and equivalents which co~e
within the spirit of the invention and which are intended
to be included herein.
