Note: Descriptions are shown in the official language in which they were submitted.
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SAW BLADE ASSEMBLY FOR A CUTTING SAW
FIELD OF THE INVENTION
The present invention relates to cutting saws. More specifically, the
invention
relates to a saw blade with removable saw tooth holders.
BACKGROUND OF THE INVENTION
Cutting saws are used to cut wood or other material. Some saws use an abrasive
disc or band for cutting while other saws use a serrated blade with a
dentated, or
toothed, outer edge.
to In the lumber industry, circular saws are used on tree-felling heads. Many
prior art
circular saws for this industry include a circular disc with tooth holders
mounted
about the periphery of the disc and supporting cutting teeth. Should a tooth
be
damaged in the process of cutting, the tooth is simply removed from the holder
and replaced. In addition, teeth of different shape and size are required for
different cutting jobs. As such, saw blades with removable saw tooth holders
provide good versatility. As the saw blade is subjected to stress and shock,
it is
important that the saw tooth holder remain securely in place not only to avoid
damaging the wood fiber and to provide a precise clean cut but also to ensure
the
safety of the operators.
Numerous saw blade assemblies are specified and known in the art.
US Patent No. 5,377,731 (Wildey) describes a saw blade of a type that is used
in
a tree felling head. The saw blade has a disc provided with tooth holders
about its
periphery that support cutting teeth asymmetrically above an inner plate of
the
disc. As shown in Figure 1 of Wildey, the tooth holders are in the form of
protrusions radially projecting from the rim of the disc. Each tooth holder
has a
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transverse central mounting bore. The mounting bore has a larger diameter_ on
one side to receive the shank of a tooth, and a smaller diameter on the other
side
to receive the shank of a bolt screwed in the shank of the tooth to hold it in
place
on the tooth holder. One problem with this tooth retaining system is that the
tooth
holders must be sufficiently spaced from one another to leave enough space for
passage of the bit used to drill the mounting bores, thereby limiting the
number of
possible teeth and tooth holders around the saw blade (e.g. to 18 teeth) and
forcing them to be undesirably remote from one another, which reduce the
cutting
efficiency of the saw blade. Also, the impact on the outer edge of the teeth
io produces a shearing force on the tooth retaining system, i.e. the shanks of
the
teeth and the bolts, causing premature wear due to the configuration of the
teeth
and of the tooth holders. The tooth holders may be separate from the disc and
are
fastened to it using bolts extending across superimposed portions of the tooth
holders and the disc. Such a mounting arrangement presents certain risks for
the
1s blade such as holders becoming loose.
US Patent No. 5,085,112 (MacLennan) describes a saw tooth and holder and
means for mounting the holder to a saw. As shown in Figure 2 of MacLennan, the
saw tooth holders straddle the arced rim of a circular disc. This requires
that the
20 surface of the tooth holder in contact with the arced rim be arced
accordingly. Any
slight differences in the arc of the rim and the arc of the tooth holder may
result in
misaligned teeth or loose tooth holders hence adversely affecting the cutting
process. In addition, the machining of the arced surfaces of the tooth holders
adds to the cost of the holders. Moreover, the arced surfaces of these tooth
25 holders render the holders saw-blade specific - the tooth holders are not
easily
interchangeable.
As such, there is a need for a saw blade assembly that alleviates at least
some of
the above-mentioned drawbacks of the prior art.
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SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a
saw
blade assembly for a cutting saw. The saw blade assembly includes a polygonal
disc having an outer edge including multiple flat sides, the outer edge
defining an
effectively circular shape, and a plurality of saw tooth holders, each being
removably mounted on a corresponding flat side of the polygonal disc. Each saw
tooth holder has a flat abutment surface abutting the corresponding flat side.
According to one embodiment, the saw blade assembly further includes fastening
io means, for each saw tooth holder, removably mounting the saw tooth holder
to the
polygonal disc. The fastening means may include a bolt extending through the
saw tooth holder and polygonal disc, and an internally-threaded bushing
cooperating with the bolt. Alternatively, the fastening means may include a
rivet
extending through the saw tooth holder and polygonal disc.
In accordance with another aspect of the present invention, there is provided
a saw
blade assembly for a cutting saw which includes a polygonal disc having an
outer
edge including multiple flat sides, the outer edge defining an effectively
circular
shape, and a plurality of saw tooth holders, each saw tooth holder removably
mounted on a corresponding flat side along the outer edge of the polygonal
disc
and straddling the corresponding flat side of the polygonal disc. The saw
tooth
holder has a body including a flat abutment surface abutting the corresponding
flat
side of the polygonal disc, a first leg extending from the body along a first
surface
of the polygonal disc, and a second leg extending from the body along a second
surface of the polygonal disc. For each saw tooth holder, the saw blade
assembly
also includes fastening means removably mounting the saw tooth holder to the
polygonal disc.
Preferably, for receiving the fastening means, the polygonal disc has at least
one
opening therethrough proximate the corresponding flat side, the first leg has
at
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least one opening therethrough, and the second leg has at least one. opening
therethrough in central axial alignment with the at least one opening through
the
first leg and the at least one opening through the polygonal disc.
According to one embodiment, the fastening means may include at least one
collared plain bushing inserted into the first leg, an internally-threaded
bushing
inserted into the second leg, and a countersink-head bolt extending through
the
collared plain bushing and threaded into the internally-threaded bushing.
According to another embodiment, the fastening means may include at least one
io rivet extending through the first leg of the saw tooth holder, the
polygonal disc, and
the second leg of the saw tooth holder.
In accordance with another aspect of the present invention, there is provided
a
polygonal disc for a cutting saw adapted for receiving a plurality of
removable saw
is tooth holders mounted thereon, each saw tooth holder having a flat abutment
surface. The polygonal disc includes an outer edge including multiple sides,
wherein the outer edge defines an effectively circular shape and each of the
multiple sides is flat for abutting the flat abutment surface of the saw tooth
holder
mounted thereon. Preferably, each of the multiple sides accommodates at least
20 one saw tooth holder.
In accordance with yet another aspect of the present invention, there is
provided a
saw tooth holder for a cutting saw that has a polygonal disc including an
outer
edge having multiple flat sides, the outer edge defining an effectively
circular
25 shape. The saw tooth holder includes a flat abutment surface for abutting a
corresponding flat side of the polygonal disc. Preferably, the saw tooth
holder is
adapted for straddling the flat side, the saw tooth holder having a body
defined by
the flat abutment surface, a first leg extending from the body, and a second
leg
extending from the body.
Advantages of the present invention include a saw blade assembly where the
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removable saw tooth holders are easily and immovably mounted onto a multi-
sided polygonal disc.
The objects, advantages and other features of the present invention will
become
more apparent and be better understood upon reading of the following non-
5 restrictive description of the preferred embodiments of the invention, given
with
reference to the accompanying drawings. The accompanying drawings are given
purely for illustrative purposes and should not in any way be interpreted as
limiting
the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
io FIG. 1 is a front view of a saw blade assembly, according to an embodiment
of the
invention, showing a plurality of saw tooth holders mounted on a polygonal
disc.
FIG. 1A is a detail view of portion A of FIG. 1, showing a mounted saw tooth
holder.
FIG. 1B is a cross-section view taken along line B-B of FIG. 1A, showing a
bolt
is mounting according to one embodiment of the invention.
FIG. 1C is a cross-section view taken along line C-C of FIG. 1A, showing a
rivet
mounting according to one embodiment of the invention.
FIG. 1 D is a top view of detail A of FIG. 1A with the flat abutment surface
of the
saw tooth holder abutting the flat side of the polygonal disc shown in phantom
line.
2o FIG. 2 is an exploded view of a saw tooth holder mounted on a polygonal
disc, in
accordance with one embodiment of the invention.
FIG. 3 is an exploded view of a saw tooth holder mounted on a polygonal disc,
in
accordance with one embodiment of the invention.
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DESCRIPTION OF PREFERRED EMBODIME-NTS OF THE INVEN-TION
The present invention will be described more fully hereinafter with reference
to the
accompanying drawings, FIGs. 1, 1A, 1 B, 1 C, 1 D, 2, and 3, in which like
numerals
refer to like elements throughout.
According to one aspect of the invention, there is provided a saw blade
assembly
for a cutting saw. The saw blade assembly is preferably intended for use in a
tree-
felling circular saw. Of course, the saw blade assembly is not limited to
being
used in wood-cutting saws - it may be used in any appropriate cutting saw, for
example a metal-cutting saw.
lo Referring more specifically to FIG. 1, there is shown a saw blade assembly
10
according to one embodiment of the invention. The saw blade assembly 10
includes a polygonal disc 12 and a plurality of saw tooth holders 22 mounted
thereon.
The polygonal disc 12 has an outer edge 18 which includes multiple flat sides
20.
Albeit multi-sided, the polygonal disc 12 is effectively circular in shape.
Each saw tooth holder 22 is removably mounted on one of the multiple flat
sides 20 of the polygonal disc 12. A saw tooth holder 22 may be mounted on
each
and every flat side 20 of the polygonal disc, or on every other flat side 20
or any
other appropriate pattern, depending on the geometry of the assembly and on
the
2o quality of the cut required (the number of saw teeth determine the quality
of the
cut). Advantageously, should the saw tooth holder 22 be damaged during use of
the cutting saw, the saw tooth holder may be removed and replaced with a new
holder. To allow for a clean and precise cut and avoid damaging the wood, a
stable and secure mounting of the saw tooth holder 22 is needed. As such, each
saw tooth holder 22 has a flat abutment surface 26 which abuts the flat side
20 of
the polygonal disc, best shown in FIGs. 1A, 1 B, 1 C, and 1 D.
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According to.the embodiments shown in the drawings, each saw tooth holder 22
straddles a flat side 20 of the polygonal disc 12 and has a body 24 which is
includes on one of its sides the flat abutment surface 26 abutting the flat
side 20, a
first leg 28 extending from the body 24 along a first surface 14 of the
polygonal
disc 12, and a second leg 30 extending from the body 24 along a second
surface 16 of the polygonal disc 12. Advantageously, the first and second legs
28
and 30 advantageously act as braces providing steady seating of the tooth
holder 22.
Of course, it is understood that the saw tooth holders 22 may be of any form
as
to long as they have a flat abutment surface 26 for abutting securely against
the flat
side 20 of the polygonal disc 12 onto which they are mounted. As any person in
the art would understand, the saw tooth holders may be further configured to
accommodate a number of specific saw teeth.
The saw blade assembly 10 may further include fastening means removably
1s mounting the saw tooth holders 22 to the polygonal disc 12. Preferably, for
ease
of assembly, the polygonal disc 12 has at least one opening 21 therethrough
proximate each flat side, and the first 28 and second 30 legs of each saw
tooth
holder 22 have at least one corresponding opening 29 and 31 therethrough in
axial
alignment with any one of the openings 21 through the polygonal disc.
2o According to one embodiment, the fastening means may include a bolt 32 and
bushing extending through the saw tooth holder 22 and the polygonal disc 12.
As
shown in FIG. 1 B and FIG. 2, the fastening means may include a collared plain
bushing 38 inserted into an opening 29 of the first leg 28 of a saw tooth
holder 22,
and an internally-threaded bushing 36 inserted into the corresponding opening
in
25 the second leg 30 of the saw tooth holder 22, and a countersink-head bolt
32
extending through the collared plain bushing 38 and threaded into the
internally-
threaded bushing 36 thereby fastening the saw tooth holder 22 to the polygonal
disc 12. Optionally, the collared plain bushing and internally-threaded
bushing may
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be replaced by a single. internally-threaded bushing inserted into the second
leg
and extending all the way through the first leg. The use of bushings allows to
minimize any damage to the polygonal disc 12 and saw tooth holder 22 due to
friction.
According to another embodiment, the fastening means may include a rivet 40
extending through the saw tooth holder 22 and the polygonal disc 12. As shown
in
FIG. 1 C and FIG. 3, the fastening means may include a rivet 40 extending
through
an opening 29 of the first leg 28 of a saw tooth holder 22, an opening 21 in
the
polygonal disc 12, and an opening 31 in the second leg 30 of the saw tooth
holder
jo 22.
According to other embodiments of the invention, the fastening means may
include a bolt (threaded or not) and some other appropriate mating lock means,
for
example a locking nut.
Although it is possible to use either one bolt 32 and cooperating internally
1s threaded bushing 36 or one rivet 40 to mount each saw tooth holder to the
polygonal disc, to increase stability and to avoid loosening of the saw tooth
holder
22, it is preferably that at least two bolts and two cooperating internally-
threaded
bushings or two rivets be used.
In accordance with another aspect of the preset invention, there is provided a
20 polygonal disc for a cutting saw having a number of removable saw tooth
holders
that have a flat abutment surface. The polygonal disc as mentioned above is
effectively circular in shape and has an outer edge with multiple sides. Each
of the
multiple sides is flat for abutting the flat abutment surface of the saw tooth
holder
mounted thereon. Preferably, each of the flat sides accommodates a single saw
25 tooth holder.
In accordance with yet another aspect of the present invention, there is
provided a
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saw tooth holder for a cutting saw that includes an effectively circular
polygonal
disc with an outer edge having multiple flat sides. The saw tooth holder as
mentioned above includes a flat abutment surface for abutting a flat side of
the
polygonal disc. Preferably, the saw tooth holder is of a form which allows it
to
straddle the flat side: the saw tooth holder has a body defined by the flat
abutment
surface, a first leg extending from the body, and a second leg extending from
the
body.
The saw blade assembly of this invention provides reliability of a one-piece
saw
io disc with the versatility of replaceable removably-mounted saw tooth
holders, but
stability and precision with its mounted saw tooth holders in flat abutment
contact
with the flat sides of the multi-flat-sided polygonal disc.
Numerous modifications could be made to any of the embodiments described
above without departing from the scope of the present invention as defined in
the
appended claims.
