CHAINSAW FOR LUMBER MAKING

SCIE A CHAINE POUR DECOUPAGE EN PLANCHES

English Abstract

A chainsaw consists essentialy of a motor driven chain
with cutting teeth. Chainsaws are widely used for
felling trees and for cutting long pieces of wood into
shorter pieces. There are devices to guide a chainsaw
axially along the grain, to make lumber from trees. All
of these devices cut across the end grain of the wood.
It is well known that cutting across end grain is slow
and energy consuming. The sawdust produced is a powder.
It is also known that a chainsaw held with the cutting
edge parallel to the grain cuts a great deal faster,
tearing out thin strips of wood instead of fine sawdust.
This invention is a means for presenting the cutting
chain substantially parallel to the wood grain, and
guiding it so as to cut flat surfaces of any length.
Tests have shown that my invention cuts lumber from
three to ten times, (depending on the type of wood),
faster than previously available chainsaw devices of
equal power. This is achieved by a novel bar of
approximately triangular shape carrying the cutting
chain, and means to guide the bar to form a flat surface
as long as any log. The novel bar and guide apparatus
are described in the following specification.

Claims

CLAIMS
The embodiments of the invention in which an exclusive
property or privelege is claimed are defined as follows:
1. An approximately triangular chainsaw bar
which comprises a first apex designed to accomodate a
sprocket driven by driving means, and an opposite side
defining a cutting portion which is thinner than the
width of a cutting chain mounted thereon, a guiding
holder attached to the bar, and a carriage on which the
holder slidably guides the bar, said cutting chain
guided by grooves in the edges of the chainsaw bar and
driven by said sprocket, said cutting portion being free
of any attachment which could prevent any part of the
cutting portion from entering into a kerf cut by the
chain, a means of attachment of the bar to a chainsaw
motor driving said sprocket, and a means of attachment
of the bar to the guiding holder, said holder designed
to slide on the carriage, permitting penetration of the
cutting portion of the bar into a log, said carriage
suitable for mounting on any flat surface, or on tracks,
to facilitate consecutive plunge cuts connecting to each
other, along the axis of the chainsaw bar, to produce a
straight kerf of any length and of a maximum depth equal
to the height of the cutting portion of the bar normal
to the cutting edge of said bar.
2. The chainsaw bar of claim 1 which comprises
idler sprockets in the edges of the bar to guide the
chain, in combination with grooves or without grooves.
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3. The chainsaw bar of claim 2 which comprises a
holder with at least two bushings or guides parallel to
the plane of the cutting portion of the bar and at an
angle, usually, but not necessarily, ninety degrees, to
the cutting edge of the bar.
4. The chainsaw bar of claim 3 which comprises a
carriage with at least two posts, upon which the holder
of claim 3 is slidably mounted with the cutting edge of
the bar approximately parallel to the base of the
carriage, suitable for mounting on a log or a bed, to
which it may be screwed or clamped in a series of
positions so that consecutive plunge cuts may make a
continuous straight kerf.
5. A bed in the form of a symmetrical track to
receive a carriage as defined in claim 4, so that the
chainsaw bar cutting portion may be plunged first on one
side of the bed to form a kerf of a desired length and
then on the other side of the bed, to cut a cant of a
given width with one position of the bed on a log.
6. A wedge shaped slider to adapt a carriage as
defined in claim 4 so that it can be slid along a bed
with the cutting edge of the chainsaw bar at a small
angle to the plane of the bed.
7. Means such as clamps or spacers for fixing
the holder at different heights on the carriage so that
cuts of chosen depth may be made using a slider as
defined in claim 6.
8. A carriage as defined in claim 4 comprising a
stop near the base of the carriage, against which the
cutting portion of the bar will slide when it is exactly
parallel to the posts of the carriage.
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Description

20534q8
SPECIFIC~TION
This invention relates to a chainsaw for making lumber.
chainsaw is a common hand held tool for cutting wood.
The cutting chain i5 driven by a small engine.
Inexpensive adapters are available to hold and guide the
chainsaw to make boards~ but all of these devices
present the chain to the end grain of the wood, a slow
and energy consuming way of cutting. Commercial
sawmills use thin bandsaws which remove less than one
quarter as much wood as does a chainsaw~ and hence use
1ess power and cut faster. Portable bandsaws are
available to compete with lumber making chainsaws~ but
they are heavy and expensive, mainly suitable for full
time c~mmercial operation. My invention is suitable for
people making their own lumber~ -
I have found that if the chainsaw chain is pressed into
the wood with the cutting edge substantially parallel to
the grain it cuts up to ten times faster than currently
available chainsaw devices. The efficiency of the
method is obvious when the resulting long thin shavings
are compared with the fine sawdust produced by present
devices which cut across the end grain of the wood.
An explanation follows of some words used in this
specification: The "bar" of a chainsaw is a thin
grooved steel plate which guides the chain. The
"holder" of the present invention is apparatus for
slidably attaching the chainsaw to a "carriage" which
can be attached to a "bed". ~n "idler sprotket" is a
sprocket in the bar groove which reduces the friction
between the bar and the chain. ~ "kerf" is a cut~ or

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2053498 ~ -
the space left by the passage of the chain in cutting.
"cant" i5 a log of which at least one side has been
flattened. "Lagging" is attaching an object to wood by
means of lag screws, which are self-tapping screws.
In drawings which illustrate embodiments of the
invention,
Figure 1 is an elevation of a chainsaw with a
triangular bar! and with a holder attached. The
conventional chain is inJicated by dotted lines.
Figure ~ is an end elevation of the embodiment shown ;~
in Figure 1~ with the chain removeJ for clarity.
Figure 3 is an end elevation of a carriage.
Figure 4 is a side elevation of the carriage.
Figure ~ is a plan view of the carriage.
Figu-e b is an end elevation of the carriage lagged
to a bed, which i5 clamped or lagged, by conventional
means not shown~ to the roughly flattened side of a log.
Figure 7 is an end elevation, on Section B - B of
Figures 8 and 9~ of a carriage designed to be clamped to
a bed~ to which it is shown fastened.
Figure 8 is a plan view of the carriage and bed of
Figure 7.
Figure 9 is a side elevation of the carriage of
Figures 7 and 8. The bed is omitted for clarity.
Figure 10 is a side elevation of a saw and holder on
a carriage mounted on a wedge shaped board called a
slider~ the slider being mounted on a bed only part of
which is shown.
Figure 11 is a partial end elevation on view ~ -
of Figure 10.

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C ~
2053498 ~
The invention illustrated comprises a triangular bar 1
attached to a motor 2 by conventional means 3 and
carrying a conventional cutting chain 4 driven by motor
sprocket 5. Idler sprockets 6 are conventional though
not essential parts of the invention. The working or
cutting length of the chain is from point 7 to point 8.
In operation, the edge 7 - 8 is approximately parallel
to the wood grain and is pressed into the wood by holder
9 sliding on bushings 10 on posts 11 of carriage 12.
Holder q is bolted by bolts 23 to bar 1 and spaced from
it to clear the chain~ by spacers 24. Spacers 24
position bar 1 parallel to the posts 11 and parallel to
the side 25 of carriage 12. Stop 22 forms additional
support to maintain alignment of bar 1, the side of
which rubs against it. Bar 1 i5 pushed through the
thickness of the tree or cant, or until stopped at
maximu,n depth of cut by bottom 13 of holder 9 touching
the top surface of carriage 12 at 14.
In the embodiment shown in Figure 6, the carriage 12 may
be bolted by two lag screws 15, in counterbored holes -
2~ to the bed. a flat board 16~ which is clamped or
lagged, by conventional means not shown, to a log 30.
Log 30 may be~ but is not necessarily, partly flattened
to support bed 16. Bed ~6 has a straigh~ guide strip
17. Carriage 12 may be successively lagged at intervals
not greater than the length of the cutting edge 7 - ~,
with side 25 against strip 17~ to form a continuous kerf
18, as wide as the thickness of the chain 4, which is
not shown in Figure 6. Bed 16 may be made of any flat
board. lt will usually be a board cut by means of thi~
invention. A chalk line may be substituted for guide
strip 17.

20534q8
In the embodiment shown in Figures 7~ 8, and 9, an
alternative carriage lq is arranged to slide on a bed
21~ and be clamped to it at intervals by clamping means
20. the quick acting clamping means 20 saves a few
seconds at each movement of the carriage 19 compared
with driving the two lag screws 15. The embodiment
shown in Figures 7 to 9 is particularly useful for
cutting a number of cants, or timbers, of a given width.
This is achieved by cutting a kerf with the saw bar on
one side of the bed, which is fixed to a log, and then
reversing the carriage to cut a second kerf on the other
side of the bed. The width of the carriage and matching
bed may be chosen to give different widths of cant.
~lternatively, clamping means 20 may be laterally
adjustable! by conventional means not shown, on bed 19
to give different overhangs of stop 22, and of bar I
with chain 4~ past the edge of bed 21~ and hence can be
made adjustab'e for different widths of cant with one
width of carriage and matching bed.
The embodiment shown in Figures 10 and 11 may also be
used. Carriage 12 is clamped or screwed to slider 26~
which can be pushed along a bed 27. ~ bed such as bed
21 shown in Figure 7 is also suitable~ but the clamping ;~
means is left free to slide. ~The wedge angle of slider ~'G
26 is small~ for example ten degrees~ so that the
cutting edge ~ - 8 of the chain is at a small angle to
the grain. The depth of cut is controlled bylstops 28
which regulate the height of holder q at a given height `
on carriage 12. ~epeated cuts with lower positions of -
the stops may be made for deeper kerfs.

` 2053498
While a triangular bar is shown~ the essential feature
of my invention is a bar with the cutting edge remote
from the apex where the motor is attached~ and with no
width of the bar with chain wider than the cutting edge.
The phrase on page 1 of this specification! "cutting
edge substantially parallel to the grain", is for
contrast with conventional lumber making devices which
use a cutting edge substantially normal to the grain.
In practice~ conventional devices may well be used about
twenty degrees off the normal to the grain, while my
inven~ion may be used in the order of twenty degrees
away from parallel to the grain. For best results it
will be close to parallel to the grain while plunging,
and between eight and twenty degrees away from parallel
when using the slider.
While Figure 1 shows the cutting edge 7-8 at ninety
degrees to the axes of the bushings 10, the angle could
be as low as seventy degrees, for example. If that
angle is between eighty-two and seventy degrees, with
the end ~ closer to the holder than end 7~ no special
adapter such as slider 26 is needed for the sliding
method of cutting.
Figures ~ 4~ 5! 6~ 8 and 9 show stop 22 as a simple
button against which one side of bar I can slide. This
stop can also be a bolt with a loosely fitting washer on
each side of bar 1, which in this case must have a long
vertical slot to accomodate the bolt. This will help to
keep the bar 1 parallel to the carriage posts 11,
compensating for play and flexibility in the system.

2053498
The slider of Figures 10 and 11 is one way of holding
the cutting edge 7-~ at an anqle to the grain. ~ny
other simple way of holding the bottom of carriage 12
free to slide at an angle on a bed such as 21, would be
suitable. For example~ a base hinged and suitably
supported to the bottom of carriage 12 could be used to
change the angle for different types of wood.
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Representative Drawing