Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
LATHE CUTTER AND CHIP FAN
Technical Field
The present invention relates to cutting a workpiece such as a log into a
circular
cross-sectional configuration while simultaneously discharging chips of
material removed
from the workpiece.
Background Art
Log shaping operations are known for lathe turning logs into relatively
uniform
circular cross sections. In a conventional method, logs are delivered in an
axial
direction through a cutter head that rotates about an axis. Cutters mounted
within the
cutter head are rotated about the axis and against the log to progressively
remove
material from the log as it is moved along. Large volumes of chips are removed
during this operation. Chip removal is typically accomplished using a high
volume,
high pressure vacuum system connected by duct work to an intake housing
situated
~5 adjacent the cutter head.
Chip collection vacuum systems are expensive, require a significant amount of
power, and require periodic maintenance and repair work. A need thus arises
for a
simple chip exhaust system.
This need is filled by the present lathe cutter and chip fan in which the
cutter
2o and exhaust are combined in a single unit in which cutters and impellers
are mounted
to a common rotary portion of a frame. The cutters rotate about the workpiece,
removing material in the form of chips. The impellers are mounted to the same
rotary
portion and therefor operate simultaneously with the cutters to produce an
airflow that
is effective to carry the chips in an airstream through a discharge and away
from the
25 cutters.
An objective of the present invention is thus to provide such a lathe cutter
and
chip fan whereby the same rotary motion of the cutter is used to produce a
discharge
airstream without requiring a chip removal vacuum system.
The above and still further objects and advantages will be understood from the
3o following description which, taken with the accompanying drawings, describe
preferred
forms of the present invention.
Brief Description of the Drawings
Fig. 1 is a perspective diagrammatic view illustrating a preferred form of the
present invention in operation;
35 Fig. 2 is a sectional view taken substantially along line 2-2 in Fig. 1;
and
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Fig. 3 is an enlarged sectional view taken substantially along line 3-3 in
Fig. 2.
Best Modes for Carr~ring Out the Invention and Disclosure of Invention
An example of a preferred form of the present lathe cutter and chip fan is
generally shown at 10 in the drawings. The lathe cutter and chip fan 10 is
provided
primarily for the purpose of cutting and removing chips 12 (Fig. 1 ) from
workpieces
14 such as logs or cants to produce finished logs of circular cross section.
The workpiece 14 is moved along an axis X through the present machine and
is held against rotation while cutters and chip fan impellers rotate. As the
workpiece
1o advances, rotating cutters engage and cut the workpiece to a prescribed
diameter. The
cutting action produces chips that are removed and discharged from the area in
an
airstream produced by the simultaneously rotating impellers.
Looking in greater detail to the drawings, an annular frame 18 (Fig. 2) is
shown
having a rotary portion 20 driven to rotate about axis X in a direction of
rotation
(clockwise in Fig. 2). A drive assembly 26 (Fig. 1 ) is provided for this
purpose.
The frame 18 and rotary portion 20 are annular and configured to receive a
workpiece or log fed along the axis X. Frames and rotary portions similar to
the above
are known in the log turning industry and need not be described in detail
herein. For
example, U.S. Patent 4,303,111 to the present Applicant, Richard L. Neville ;
and
4,519,429 to Dreese are exemplary of annular frames mounting annular rotated
cutter
mounting parts. Portions of these patents related to the annular frame and
cutter
mounting rotary portions thereof are hereby incorporated by reference.
Further, the
incorporated Neville patent also shows a feed mechanism used for supporting
and
delivering successive workpieces through a cutter. The present invention may
be
utilized with this or other appropriate feed mechanisms capable of delivering
and
feeding an elongated workpiece such as a log or cant along a prescribed
longitudinal
path through the present cutter and chip fan 10.
As shown in Fig. 2, the frame 18 includes an annular stationary part 22 that
may be held in a fixed position by an appropriate support structure (not
shown). The
3o stationary part 22 rotatably supports the rotary portion 20 which may be
driven to rotate
by the drive assembly 26. In the example illustrated, the drive assembly 26 is
an
electric motor and belt assembly drivingly connected to the rotary portion 20.
Another
drive mechanism such as an appropriate hydraulic motor could be used. Further,
a
different driving linkage such as a conventional chain and sprocket drive
could be used.
Appropriate gearing could also be used.
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The frame 18 and rotary portion 20 define a workpiece opening 24 through
which the workpiece may be fed. The opening 24 is selected to be larger than
the
largest diameter (or cross-section) workpiece. Also, the opening 24 is most
preferably
centered on the axis X.
In preferred embodiments, at least one and more preferably a number of
cutters 28 are mounted to the rotary portion 20. The cutters 28 project into
the
workpiece receiving opening 24, and are configured to rotate with the rotary
portion 20
and cut material from a workpiece positioned within the workpiece opening 24.
Each of the cutters 28 (Fig. 3) advantageously includes a post 30 that is
adjustably mounted for substantially radial adjustment in an guide member 32.
The
guide member 32 is substantially securely mounted to the rotary portion 20 of
the
frame. A cutting blade 34 is releasably mounted at a radial inward end of the
post 30.
Mounting bolts 38 permit removal and re-sharpening of the cutter edge 36 (Fig.
2).
The mounting bolts 38 and post end orient the cutter edge at a preferred angle
to
~5 enable the cutter edge to slice through the workpiece as the cutter is
rotated.
A preferred adjuster 40 is provided for each cutter, connecting the associated
guide member 32 and post 30 to facilitate substantial radial adjustment of the
cutter
edge 36 toward or away from the workpiece 14. The adjuster 40 is preferably
comprised of a bolt 42 captured against axial movement but freely rotatable in
relation
2o to the guide member (see Fig. 3). The bolt shank threadably engages a nut
46 that is
welded or otherwise secured to the adjacent post end such that rotation of the
bolt will
result in movement of the post and cutter blade.
It is pointed out that several cutters 28 as described above are provided. The
preferred cutters are equi-angularly spaced about the rotary portion 20 as
shown in
25 Fig. 2. In the configuration example illustrated, four cutters 28 are
mounted to the
rotary portion 20 in diametric opposition. It is possible, however that more
or fewer
cutters be used, but it remains desirable that they be equi-angularly spaced
for balance
and even application of torque through the rotary portion 20.
In preferred forms, the cutting blades 34 are positioned at differing radial
3o positions in relation to the workpiece such that the workpiece will be
progressively cut
to a desired diameter. This may be selectively accomplished by operation of
the
adjusters 40.
A plurality of impellers 52 are mounted to the rotary portion 20 for rotation
therewith. Each impeller 52 is configured to produce an airflow to carry and
discharge
35 chips 12.
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It is preferable that the impellers 52 each include a planar working surface
54
that is substantially radially oriented with respect to the axis X. It is also
preferable
that an impeller be mounted to each of the guide members 32, separately from
the
posts 30. Adjustment of the cutters is thus an operation separate from the
impellers.
That is to say the impellers are not necessarily radially adjustable with the
cutting
blades.
Each preferred impeller extends substantially radially from an inside edge 56
to
an outside edge 58. The inside edges 56 are radially outwardly adjacent the
cutting
blades 34, and the outside edges 58 are situated closely adjacent to a housing
to be
described below.
The planar working surfaces 54 extend between the edges 56, 68 and lie within
substantially radial planes that are adjacent to the cutting edges with
respect to the
direction of rotation as shown by Fig. 2. This places the impellers forwardly
of (with
respect to the rotational direction) and directly adjacent to the respective
guide
~5 members 32. In preferred forms, the impellers are bolted to the guide
members 32.
The working surfaces of the impellers will thus protect the guide members 32
and
adjusters 40 from clogging with chips during operation.
A housing 62 forms a compartment 64 about the rotary portion 20 and
cutters 28. The housing includes a central housing openings 66 that are
substantially
2o aligned axially with the workpiece receiving opening 24.
In preferred forms, the housing is substantially circular and centered on the
axis X. It includes a substantially circular outer wall 68 that is situated
slightly
outward of the outside impeller edges 58, and transverse end walls 70 that are
axially
adjacent radial edges of the impellers and define the openings 66. The housing
thus
25 substantially encases the cutters 28 and the impellers 52.
A chip discharge 72 openly communicates with the compartment 64 and is
situated substantially tangentially with respect to the rotational path of the
cutters 28.
Assuming a clockwise rotational direction of the cutters 28 and impellers, an
open
intake end 74 of the discharge 72 is positioned in the lower left quadrant of
the
3o housing as shown in Fig. 2, opening into the compartment. This position is
preferred
to take advantage of gravity since chips will naturally tend to fall from the
workpiece.
If, on the other hand, the orientation of the cutters and impellers were
reversed, and if
the rotary portion were driven in a counter clock-wise direction, the chip
discharge
would most preferably be situated in the lower right quadrant of the housing.
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The discharge 72 leads from the intake end 74 to an exhaust end 76 that is
shown in Fig. 1 discharging chips 12. However it may well be desirable to
connect
the exhaust end 76 to conventional ducting (not shown) that will lead away to
a chip
collection area (not shown).
5 The cutters 28, impellers 52 and rotary portion 20 of the frame are free to
rotate
together within the housing 62. Such rotation is assumed to be in a clockwise
direction
as viewed in Fig. 2, and is preferably within a range of about 150 and 300
RPM.
Rotational speeds within this range may be selected according to the size and
consistency of the workpiece, and the workpiece feed rate. For cutting soft
woods such
as spruce and fir, an rpm range of between 200 and 250 has been found
effective.
With the present combination cutter and fan arrangement, the rotational speed
may be determined by the material being cut and the feed rate, not by
airstream
requirements for chip removal. It has been found that with the described
impeller and
housing arrangement, the present rotational speed range is sufficient to
facilitate a
~5 smooth cutting operation and to simultaneously create enough airflow to
remove chips
from the cutting area. Chips of workpiece material removed from the workpiece
by the
cutter may be thus be removed and discharged in the airflow through the chip
discharge,
all in response to rotation of the rotary portion 20 of the frame; and thus
all in
response to operation of a single drive source 26.
2o Prior to operation, the cutters are adjusted to cut a workpiece to a
desired
diameter. This is done using the adjusters 40, preferably in a manner such
that the
cutters will take progressively deeper cuts in the workpiece as they are
rotated. Thus
it may be that only one of the cutters is set to the final diameter and the
remaining
three are set to progressively larger diameters. Once the adjustments are
made, the
25 drive 26 is activated to start the cutters 28 and impellers 52 rotating.
In operation, a workpiece 14 is fed by existing conveying mechanisms (not
shown) along the axis X and through the axially aligned workpiece opening 24
and
housing opening 66. The cutters, now rotating at a rate between 150 and 300
rpm
begin to engage and progressively cut the workpiece to the prescribed
diameter.
3o Each cutter will dislodge chips from the workpiece. At least a portion of
the
dislodged chips from each cutter will pass under the radially adjacent
impeller 52 and
strike the following impeller. This impeller will cause the chips to move
radially
outwardly due to centrifugal force. Further, the rotating impellers will
create a
substantial airflow, with intake air being drawn into the housing 62 through
the housing
35 openings 66. The in-rushing air will carry chips outwardly toward the outer
wall 68
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of the housing, and in ~an expanding circular path due to the rotating
impellers 52.
Finally the chips, traveling at high velocity in the air current will be
discharged through
the chip discharge 72. The outwardly guided chips may be carried by the
exhausting
airstream to a remote collection site, simply by force of the air current
created by the
impellers.
It is noted that the chip cutting and exhaust functions are accomplished using
the same drive. There is no need for auxiliary chip vacuum systems because the
present lathe cutter and chip fan 10 functions well to complete both cutting
and chip
removal functions. The result is a substantial savings in equipment,
maintenance and
repair.
