Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02842972 2014-02-13
SAW DISK WITH IMPROVED CHIP DISCHARGE
(0001]This is a Divisional of Canadian Patent Application
No. 2,758,892 filed November 17, 2011.
TECHNICAL FIELD
(0002]The present invention relates generally to cutting
disks for rotary cutting machines, and more particularly
to a circular saw disk configured to provide improved
chip discharge therefrom.
BACKGROUND
(0003]Rotary cutting machines, such as circular saws,
brush mowers, stump grinders and the like, are used in
various applications which include, but are not limited
to, felling trees and other natural plant growth in the
forestry industry, cutting rock and/or earth in the
mining and construction industries, cutting up items such
as used tires and other man-made products in various
industrial applications, mowing brush and other material,
and in agriculture. Relatively smaller circular saws are
further used in countless other smaller-scale
applications, from home renovation to commercial
construction. Depending on the type of circular saw, the
central disk of the saw either rotates (particularly for
the smaller circular saws, for example) or remains
rotationally fixed but has teeth on linked holders which
rotate about the periphery of the saw disk, much as per
chain saws.
(0004] Regardless of the type of circular saw, a plurality
of such cutting teeth rotate, whether independently about
the periphery of the rotationally-stationary disk or
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together with the rotating disk when fixed thereto, in
order to cut into the workpiece material to be cut.
[0005] Known saw disks, particularly large circular saws
such as those used for felling trees or cutting through
large volumes of material, typically include a plurality
of saw teeth positioned about the periphery of the disk.
Often, these saw teeth are removable from an associated
holder that is mounted to the circular periphery of the
saw disk. This enables
broken saw teeth and/or teeth
with worn cutting edges to be removed for either
replacement, repair or re-conditioning. Each of these
holders project substantially radially outward from the
circular disk, as seen in Fig. 4, allowing the removable
teeth to be fastened thereon.
[0006] Such saw teeth are typically mounted to the outer
peripheral edge of the circular saw disk at an angle, for
example at an angle that is slightly greater than a
tangential axis relative to the outer perimeter of the
saw disk. Accordingly, the material chips which come off
the cutting edge or edges of each saw tooth must be
discharged from between the saw teeth and away from the
disk, such as to permit optimal cutting. While the
rotation of the saw disk tends to aid in this discharge
of material chips, it has been found that chips sometimes
remain lodged between teeth and the next adjacent tooth
holder about the outer periphery of the saw disk.
[0007]Accordingly, a disk for a rotary cutting machine
which provides improved chip discharge is sought.
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SUMMARY OF THE INVENTION
[0008] In accordance with an aspect of the present
invention, there is provided a circular saw disk
comprising a disk body having a central axis of rotation
and a circumferentially extending outer periphery, a
plurality of circumferentially spaced apart tooth holders
being disposed on the outer periphery of the disk body,
each of the tooth holders being adapted to receive a saw
tooth mounted thereto, a chip pocket being defined in the
outer periphery of the saw disk adjacent each of said
tooth holders such as to receive a tooth-produced chip
therein, the chip pocket being defined by a chip
clearance surface being curved along an entire
circumferential length of the chip pocket and extending
concavely into the disk body from the outer periphery
thereof to form a radially concave cavity in the disk
body defining the chip pocket.
[0009] In accordance with another aspect of the present
invention, there is also provided a method of forming a
more wear-resistant circular saw disk, the saw disk
defining a central axis of rotation and having a
plurality of circumferentially spaced apart saw teeth
removably mounted to an outer periphery of a disk body of
the saw disk, the method comprising: forming a plurality
of concave chip pockets in the disk body, including
forming a chip clearance surface being curved along an
entire circumferential length of the chip pocket and
extending radially inwardly into the disk body from the
outer periphery thereof to form one of said concave chip
pockets between circumferentially adjacent ones of the
cutting teeth on the cutting disk, each said concave chip
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pocket being adapted to receive a tooth-produced chip
therein.
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BRIEF DESCRIPTION OF THE DRAWINGS
(0010] Further features and advantages of the present
invention will become apparent from the following
detailed description, taken in combination with the
appended drawings, in which:
[0011] Fig. 1 is a side elevation view of a saw disk in
accordance with one aspect of the present invention;
[0012] Fig. 2 is a partial, enlarged side elevation view of
the saw disk of Fig. 1, taken from region 2 in Fig. 1;
[0013]Fig. 3 is a cross-sectional view of the saw disk of
Fig. 1, taken through line 3-3 in Fig. 1; and
[0014] Fig. 4 is a partial, enlarged side elevation view of
a saw disk of the Prior Art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
(0015] The present disclosure relates generally to a
cutting disk of a rotating cutting machine. Rotary
cutting machines as defined herein are intended to
include any cutting machine having a rotating disk, drum,
cylinder or chain, etc, which has teeth about the
circumferential periphery thereof, whether the teeth are
fixed to the disk/drum/cylinder which in turn rotates or
alternately the teeth rotate about the periphery of a
fixed disk/drum/cylinder. Such rotary
cutting machines
may include, for example only, circular saws, chain saws,
brush mowers, stump grinders, material shredders and the
like. Such rotary
cutting machines may be used in
various applications which include, but are not limited
to, felling trees and other natural plant growth in the
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forestry industry, cutting rock and/or earth in the
mining and construction industries, shredding items such
as used tires and other man-made products in various
industrial applications, mowing brush and other material,
and for cutting or grinding in agriculture.
[0016] The term "saw tooth" or "cutting tooth" is used
herein to refer to a cutting implement or tooth for use
in a rotary cutting machine as defined above.
Preferably, although not necessarily, such cutting teeth
are replaceable and therefore the cutting teeth are
removably mounted to the periphery of a disk or drum of
the machine, such as a circular saw having a saw disk
with such replaceable saw teeth mounted about the
periphery thereof, either fixed directly thereto or
through a holder. It is therefore understood that such
cutting teeth include teeth mounted to a rotating cutting
machine that is not a circular saw, such as a drum mower,
brush cutter or grinder, and that these cutting teeth can
be either removably mounted or permanently fixed to the
disk or drum.
[0017] Referring now to Figs. 1-3, a saw disk 10 in
accordance with one aspect of the present disclosure
includes a disk body 12 which defines a substantially
circular shape and has a central axis of rotation 14
about which the disk is rotated when in use in a circular
saw or other rotary cutting machine. The disk body 12 of
the saw disk 10 includes a circumferentially extending
outer periphery 16, which generally interconnects the
planar surfaces 15 on opposed sides of the substantially
flat disk body 12. A plurality of circumferentially
spaced apart tooth holders 18 are disposed on the outer
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periphery 16 of the disk body 12 and which, at least this
embodiment, protrude generally radially outward from the
outer periphery 16 and therefore also from the central
axis of rotation 14 of the disk. The tooth holders 18 are
preferably integrally formed (i.e. monolithic) with the
disk body 12, however it is also possible to separately
form the tooth holders and fasten them, likely but not
necessarily permanently, to the outer periphery 16 of the
disk body 12.
(0018]As seen in Fig. 2, each of the tooth holders 18 is
configured to receive at least one cutting tooth 20
thereon, such as to form a toothed circular saw disk. The
cutting teeth 20 are preferably removably mounted to the
tooth holders 18, thereby permitting each of the cutting
teeth 20 to be individually removed and replaced as
required. However, it is to be understood that the
cutting disk 10 may alternately have cutting teeth 20
thereon which are permanently fixed to the outer
periphery of the disk body, whether by regularly
protruding holders 18 as shown in Fig. 1, or alternately
by other fixation means. Accordingly, the cutting disk or
saw disk 10 of the present disclosure may simply include
a disk body 12 having a plurality of circumferentially
spaced apart cutting teeth 20 mounted to the outer
periphery 16 thereof.
[0019]As seen in Figs. 1 and 2, the saw disk 10 has a
plurality of large chip pockets 22 formed in the outer
periphery 16 of the disk body 12. The chip pockets 22 are
circumferentially spaced apart about the outer periphery
16 and located such that a chip pocket 22 is disposed at
least immediately in front of each tooth holder 18 and/or
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each cutting tooth 20, relative to a direction of
rotation 23 of the cutting disk 10 about the axis of
rotation 14. Accordingly, the chip pockets 22 are
circumferentially spaced apart such that at least one
chip pocket 22 is defined in the circumferential outer
periphery 16 of the disk body 12 between each of the
circumferentially spaced apart tooth holders 18. Each
chip pocket 22 may circumferentially extend, as shown in
Fig. 1 for example, substantially uninterrupted between
adjacent tooth holders 18.
(0020] Each of the chip pockets 22 is located and formed in
such a manner so as to receive a material chip therein
which is produced by the cutting teeth 20 when the saw
disk is in operation. The chip pockets 22 therefore
provide for improved chip discharge from the saw disk 10
due to the pocket or cavity which enables a chip produced
by the cutting tooth to be first smoothly received in the
pocket and subsequently discharged therefrom, by
centrifugal force, once the saw disk is free of the tree
or other material being cut.
(00211As seen in Figs. 1 and 2, the chip pockets 22 are
preferably formed by a radially inwardly curved chip
clearance surface 24 which extends inwardly into the disk
body 12 to form the chip pocket 22 between
circumferentially adjacent ones of the tooth holders 18.
Accordingly, this radially inwardly curved chip clearance
surface 24 is substantially concave to define a
substantially concave open cavity 50 which forms the chip
pocket 22. This concave
cavity 50 formed between the
tooth holders 18, and therefore the cutting teeth 20
mounted thereto, provides more room for the chip to be
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accommodated and subsequently discharged during operation
of the saw disk, which in turn reduces disk wear over the
life span of the saw disk. This may be particularly
useful for applications where the saw disk 10 is used in
an environment having sand, grit or other particulate
debris which causes wear, which have been known to create
cracks in the disk. Accordingly, the concave curved chip
clearance surface 24 helps to reduce such cracks from
occurring in the disk, while permitting the concave
pocket 22 formed thereby to receiving a chip which can
easily slide into the chip pocket once cut from the tree
by the cutting teeth 20, and then cleanly be discharged
from the chip pocket due to centrifugal force.
[0022]As best seen in Fig. 2, the concave open cavity 50
defined by the radially inwardly curved chip clearance
surface 24 is such that a radial thickness of an outer
peripheral portion 16 of the disk is non-constant between
adjacent tooth holders 18, such that the curved chip
pocket similarly defines a radial depth that is non-
constant in a circumferential direction. More
particularly, in the depicted embodiment, a first radial
thickness 52 of the outer peripheral rim 51 of the disk
16, at a substantially midpoint of the concave cavity 50,
is less than a second radial thickness 54 of the outer
peripheral rim 51 of the disk at a point therein
proximate the tooth holders 18 on either end of the chip
pocket 22. As such, as
seen in Fig. 2, the concave
cavity 50 formed in the disk outer peripheral surface is,
in at least the depicted embodiment, substantially
crescent shaped, having a greater radial cavity depth at
circumferential midpoint of the chip pocket and a small
radial cavity at opposed ends of the chip pocket.
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(0023]The curved chip clearance surface 24 has a forward
end 25 that may, in at least one possible embodiment,
integrally extend into a radially extending rear surface
29 of the next adjacent tooth holder 18, such as to form
a smooth curvature along a full length of the chip
clearance surface 24. This curved surface helps the chip
to readily slide into the chip pocket 22 at the tooth end
thereof once the chip is produced and then slide out of
the chip pocket again upon discharge by centrifugal
force.
[0024]As best seen in Fig. 2, the concave curved chip
clearance surface 24 defines a radius of curvature which
may, in at least one embodiment, be substantially
constant along a majority of the circumferential length
of the chip pocket and which substantially continuously
extends between the adjacent tooth holders. In one
possible embodiment, however, the radius of curvature of
the concave chip clearance surface 24 may become smaller
at the forward end 25 thereof as noted above.
[0025]Additionally, a chip mounting plateau surface 26 may
be provided immediately adjacent the front edge 28 of
each tooth holder 18 such as to permit the cutting tooth
20 to be securely mounted to the tooth holder. This
plateau mounting surface 26 may for example be used to
help prevent rotation of the cutting tooth when removably
mounted to the tooth holder 18, thereby supporting and
helping to locate the cutting teeth in place about the
periphery of the saw disk. Although in the embodiment
shown in Fig. 2 the cutting teeth 20 extend at least
partially beyond the plateau surface 26 such that they
overhang a portion of the curved chip clearance surface
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,
,
24 and thus extend somewhat into the chip pocket 22, it
is to be understood that this plateau surface 26 and the
tooth 20 may be so configured such that the cutting tooth
20 fits flushly on the plateau surface 26 and therefore
does not unduly protrude out into the chip pocket 22.
(0026] As best seen in Fig. 3, the concave cavity 50 formed
by the curved chip clearance surface 24 in the outer
periphery 16 of the disk is such that the chip pocket 22
formed thereby has open lateral sides. However, it is
also possible that the chip pocket 22 is at least
partially enclosed on the lateral edges thereof,
providing that the chip produced from the cutting teeth
20 can still smoothly enter the chip pocket 22 without
obstruction and subsequently be readily discharged
therefrom, for example by centrifugal force of the
rotating disk.
V027]As seen in Fig. 2, the cutting teeth 20 are
preferably removably mounted to the tooth holders 18 such
that the teeth can be removed and replaced when required,
for example when the teeth become worn.
However, as
noted above, in an alternate embodiment whereby the
entire disk is replaced when worn (for example for a
smaller circular saw disk intended for domestic or light
industrial use), the cutting teeth 20 may be permanently
fastened to the outer periphery 16 of the saw disk body
12 using either the radially projecting tooth holders 18
or an alternate mounting means, for example whereby the
teeth are permanently fastened (by welding, for example)
and/or integrally formed with the outer periphery of the
disk.
In the depicted embodiment of Figs. 1-3, each
tooth 20 is removably fastened to a tooth holder 18 using
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a fastener 30, such as a bolt, which extends through a
bore 32 formed in the tooth holder 18 which mates with
the cutting tooth 20 such as to removably fasten the
cutting tooth in place on the disk periphery. Alternate
removable fastening configurations may of course also be
employed.
WM While the chip pocket 22 which extends inwardly into
the disk body has been generally described above with
reference to the depicted embodiment whereby the chip
clearance surface 24 is curved and thereby forms a
concave chip pocket, is to be understood that chip
pockets having other shapes, such as one having a chip
clearance surface which is not necessarily curved, may
also be possible. For example, a rectangular and/or
square shaped chip pocket may also be formed between each
of the tooth holders 18. Provided that the chip pocket
so formed is configured such that it is sufficiently
large to receive therein a material chip produced by the
cutting teeth 20 during a cutting action and subsequently
discharged from the chip pocket, other shapes of chip
pockets can be used. As such, the chip discharged
surface 24 may neither be continuous nor curved, provided
that the chip pocket 22 formed thereby performs the
above-noted functions. However, having a curved chip
discharged surface 24 may help reduce the occurrence of
cracks forming in the disk, particularly when the saw
disk is employed in a high stress environment, for
example where abrasive material such as sand and grit may
be present.
(0029]Fig. 4 schematically shows a peripheral edge of a
prior art saw disk which is absent of any chip discharged
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pockets between the tooth holders and/or teeth of the saw
disk. More
particularly, the outer peripheral surface
between each of the tooth holders is not radially inwardly
curved or otherwise formed such as to define a radially
inwardly extending chip pocket.
Accordingly, in the
standard configuration of prior art disks, material chips
tend to become jammed between adjacent cutting teeth and/or
teeth holders, and do not readily discharge during
operation of the saw disk. This has been found to unduly
speed up the wear of the disk and/or cutting teeth, which
is clearly undesirable.
[0030] The embodiments of the invention described above are
intended to be exemplary. Those skilled in the art will
therefore appreciate that the forgoing description is
illustrative only, and that the scope of the claims should
not be limited by the preferred embodiments set forth
herein, but should be given the broadest interpretation
consistent with description as a whole. Accordingly, the
present is intended to embrace all such alternatives,
modifications and variances which fall within the scope of
the appended claims.
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