Note: Descriptions are shown in the official language in which they were submitted.
September 22, 1993
ZERO LEAD PLANER
BACKGROUND OF THE INVENTION
The present invention relates generally to wood processing
apparatus, and particularly to a planer producing smooth surfaced
high grade dimensioned lumber.
A planer is a crucial portion of a dimensioned lumber
manufacturing process. The planer takes rough sawed boards and
cuts each surface to provide a smooth, planed final product.
Planers operate at tremendous production levels. For example, a
typical planer will run on average 1, 400 lineal feet of dimensioned
lumber per minute. The planer feeds a downstream process including
grading, sorting and stacking stations. If the planer goes off
line, the entire operation shuts down and production is lost.
Thus, maintaining constant, high output by the planer is crucial to
overall production.
Because planers operate at such high capacity and with close
tolerance relative to board dimensions, boards sometimes become
jammed in the planer and require manual removal. Typically, the
planer operator must shutdown the planer and physically manipulate
the planer, e.g., move vertically a pressure plate opposing a
cutter head, to remove jammed or oversized wood articles. As may
be appreciated, the operator must quickly resolve any such jams to
1
maintain high production levels. Another source of production Loss
is the need to dismount cutter heads. While spare cutter head
assemblies may be available for mounting, the process of removing
supporting shafts, bearing housings, and cutter heads requires
time, operator effort, and the assistance of lifting devices, e. g. ,
a crane. Thus, the task of removing a cutter head assembly and
mounting a new cutter head assembly can significantly decrease
production levels.
Planers often introduce defects into the resulting product due
to board instability as it encounters the planer cutter heads.
Such defects devalue a given percentage of the production run.
FIG. 1 illustrates schematically a top view of a conventional
planer arrangement including a first infeed roller pair 12 and a
second infeed roller pair 14. Each roller pair l2 and 14 includes
an upper roller and a lower roller, FIG. 1 illustrating only the
upper rollers 12a and 14a, it being understood that directly below
rollers 12a and 14a are corresponding lower rollers of each roller
~ pair. Roller pairs 12 and 14 capture a board between the upper and
lower rollers and propel the board past a top cutter head 16 and a
bottom cutter head 18. Cutter head 16 cuts the upper surface of
the board as the board bears against an opposing bed plate (not
shown in FIG. 1) while slightly downstream cutter head 18 cuts the
lower surface of the board as the board bears against an opposing
top pressure plate thereabove. Planer 10 further includes
2
_ _
downstream a left side cutter head 30 and a right side cutter head
32 planing left and right sides, respectively, of the board passing
therebetween.
Thus, a board driven through planer 10 by feed roller pairs 12
and 14 passes by the cutter heads 16, 18, 30, and 32. The
rotational direction of roller pairs 12 and I4 define a feed
direction 20. To maintain the board stable throughout the planing
processing, a guidebar 34 defines the feed path. The board must be
maintained stable against the guidebar 34 to achieve a smooth
planed surface on all sides of the board and avoid planing defects.
Traditional planers maintain the board against the guidebar 34 by
providing an angled lead for the board relative to a planer
centerline. More particularly, each of the rollers 12 and 14 and
the cutter heads 16 and 18 have parallel axes of rotation 36, 38,
40, and 42, respectively. The axes of rotation 36, 38, 40, and 42
are all normal, i. e. , ninety degrees, to a planer 10 centerline 44 .
Force vectors developed by roller pairs 12 and I4 and by cutter
heads 16 and 18 and applied to the board are, therefore, parallel
to centerline 44. Guidebar 34 lies parallel to an angled datum
line 45, with datum line 45 more widely separated from centerline
44 at the infeed portion of planer 10 then at the downstream or
outfeed portion of planer Z0. The face 34a of guidebar 34 has a
given, slight angled relationship relative to the axes of rotation
36 and 38 for feed rollers 12 and 14. The force of movement
applied to the board by roller pairs 12 and 14 is, therefore, into
3
. _. .. _ _ .. .
the face 34a guidebar 34 rather than parallel to guidebar 34. As
a result, board 20 is maintained against guidebar 34 by virtue of
the angled lead established between the board and roller pairs 12
and 14.
Despite this angled lead arrangement maintaining the board
against guidebar 34, traditional planers still suffer from
instability of the board as its passes through the planer. When
the board is not well set against the guidebar 34 as it encounters
the cutter heads 16 and 18, lateral movement of the board relative
to guidebar 34 results and a defect known as a "snipe" wherein the
cutter head digs excessively into the board surface and thereby
downgrades the board. It is estimated that snipping of dimensioned
lumber can downgrade as much as five to seven percent of a
production run. As may be appreciated, five to seven percent
downgrade of processed lumber can, over time, result in significant
loss of overall product value.
To solve snipping problems in planers, prior designs have
included holdover shoes or snipe shoes positioned as additional
short guidebars creating lateral counter forces directly against
the board forcing it to maintain contact with the guidebar 34 as
the board passes the cutter heads 16 and 18. Unfortunately, force
applied to the board as it moves rapidly through the planer results
in frictional heat buildup, especially in the guidebar 34. As a
result, guidebars have required water cooling systems to dissipate
4
such heat energy and avoid the risk of f ire in the planer
machinery. Generally, prior planer designs have merely attempted
to increase the lateral forces applied directly to the board to
maintain the board stable against the guidebar 34 and thereby
reduce the occurrence of snipping defects. Such additional
snipping or holdover shoes add to the complexity of the machine and
should not be considered a solution to the problem of snipping in
a planer due to the associated frictional heat buildup.
Accordingly, it would be desirable to minimize the effect of
snipping in a planer without including such excess apparatus, i.e.,
holdover shoes and snipping shoes, while still resolving the
problem of stability of a board against a guidebar while the board
moves rapidly through a planer. It would be further desirable to
make more efficient the operation of a planer by minimizing
operator effort required to accomplish such tasks as cutter head
change over and correcting jammed or oversized wood articles.
SUMMARY OF THE INVENTION
The present invention recognizes the source of instability in
a board moving through a planer. In particular, the present
invention recognizes that instability of a board relative to the
guidebar results from the relative orientation of the board to the
cutter heads. While the feed rollers provide appropriate force
vectors to drive the board into the face of the angled guidebar,
the cutter heads in fact develop force vectors in the opposite
5
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direction and tend to kick the board away from the guidebar.
The cutter heads rotate opposite that of the feed rollers
and the angled lead arrangement normally used in a planer is
with respect to the feed rollers not the cutter heads. In
particular, as the leading corner of the board hits the
oncoming first blade of the cutter head, the blade tends to
kick the board away from the guidebar. As a result, the
board is generally unstable at this critical point and
snipping is more likely to occur.
According to a broad aspect of the present
invention, there is provided a planer for surfacing a wood
article, the planer comprising: a feed element applying a
feed force to said wood article; a guide element adjacent
said feed element and including a face slidably engaging
said wood article, said feed force being generally parallel
to said face but including a force component directed into
said face whereby said wood article is maintained against
said face when propelled by said feed element; and a cutter
element surfacing a portion of said wood article and
applying a cutting force to said wood article, said cutting
force being parallel to said guide element face.
In accordance with the present invention, an
angled lead arrangement is established with respect to the
feed rollers for driving the board into the face of the
guidebar, but a zero lead arrangement is established with
respect to the upper and lower cutter heads. Thus, the
board has a lead angle with respect to the axes of rotation
for the feed rollers, but travels generally normal to the
axis of rotation for the upper and lower cutter heads. A
zero lead relationship, i.e., ninety degrees, between the
6
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board and cutter head axes of rotation is established and
force applied to the board by the cutter heads is generally
parallel to the guidebar and to the board. As a result,
cutter head force vectors applied to the board are
longitudinal and do not disrupt stability of the board
against the guidebar. Improved processing results with
fewer occurrences of downgrading, e.g., snipping.
Accordingly, overall production is improved by recovering
more value from the processed lumber.
6a
Because the force of board instability is reduced or
substantially eliminated, i.e., by virtue of the zero lead
relationship of the cutter heads, many other sources of force
applied directly to the board to maintain the board against the
guidebar are reduced and may be set to engage only twisted or
crooked boards. More particularly, many of the additional snipe
and holdover shoes could possibly be removed. Furthermore, an even
smaller lead angle for the guidebar as it relates to the feed
rollers can be used. Normally, a one-sixteenth inch over one foot
angle is used as a lead relationship between the guidebar and the
planer centerline. Under the present invention, however, because
the board experiences less cutter head force vectors tending to
move it away from the guidebar, a smaller lead angle may be
employed, e.g., perhaps one-thirty second inch over one foot, and
thereby further reduce heat friction developed along the guidebar.
In accordance with one aspect of the present invention, a
planer remains more constantly in service by reducing the time and
effort required to service the planer during operation. In
particular, a planer cutter head is more quickly dismounted by
virtue of a hinge mounted bearing arrangement. The hinge mounted
bearing arrangement maintains a bearing housing on an articulated
hinge whereby the cylindric bore of the bearing housing may be
moved precisely co-axially along a cutter head support shaft. The
supporting hinge arrangement allows the operator to quickly
dismount the bearing housing, replace the cutter head on the
7
- _ - ~ _
support shaft, and then quickly remount the bearing housing.
In accordance with another aspect of the present invention, a
modular, stackable cutter head includes individual cutter head
modules stackable and slidably positioned upon a support shaft for
improved planer maintenance. The cutter head modules may be used
on either top or bottom cutter head assemblies, and include
overlapping cutter blades between adjacent modules to accomplish
smooth planing of dimensioned lumber. Because the cutter head
modules are each of relatively lighter weight than a traditional
cutter head, the cutter head modules may be manually mounted upon
a shaft without the aid of a crane. Accordingly, cutter head
change over is more rapidly accomplished. Furthermore, due to the
modularity of the stackable cutter head under the present
invention, cutter head modules may be moved relatively within a
given set of cutter head modules to produce more even wear of
cutter blades, i.e., move less worn blades to a position
experiencing more wear. As a result, more complete and versatile
use of cutter blades is accomplished.
'
In accordance with another aspect of the present invention, a
pressure plate opposing one of the cutter heads is air regulated
and remotely controlled. As a result, a jam condition in the
planer may be relieved by remote actuation of the pressure plate,
i.e., more widely separating the pressure plate and the opposing
cutter head to allow the jammed article to pass through, for
8
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improved overall operation. Air pressure is used as a
biasing or regulating force whereby, upon presentation of
sufficiently large jamming force, the pressure plate moves
automatically away from the opposing cutter head to reduce
the potential for damage to the planer and more quickly
relieve a jammed or oversized board condition.
According to another aspect of the present
invention, there is provided in a planer for surfacing a
wood article with a cutting element, an improvement
comprising: a pressure plate opposing said cutter element
to capture said wood article against said cutter element for
surfacing of said wood article; a slidable mounting
arrangement for said pressure plate allowing movement of
said pressure plate toward and away from said cutter
element; a planer frame; and a biased coupling between said
pressure plate and said frame whereby said pressure plate
maintains a given separation from said cutter element and
resists said slidable movement up to a given magnitude of
force along a direction of said slidable movement.
According to a further aspect of the present
invention, there is provided in a planer including a cutting
head mounted upon a shaft defining a first axis and having a
cylindric distal end and including a frame, an improved
bearing housing for support of the distal end of said shaft,
said bearing housing comprising: a bearing housing
including a cylindric sleeve for receiving and rotatably
supporting said distal end of said shaft, said sleeve
defining a second axis, said bearing housing including a
first flange; a first link rotatably coupled at a first end
thereof to said first flange; a second link rotatably
9
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coupled at a first end thereof to a second end of said first
link; a second flange fixedly attached to said planer frame,
a second end of said second link being rotatably coupled to
said second flange whereby said bearing housing is
maintained at a given vertical position maintaining said
first and second axes in a horizontal plane and said first
and second axes may be manually aligned without manually
supporting the weight of said bearing housing for sliding
said sleeve on and off said cylindric distal end of said
shaft.
The subject matter of the present invention is
particularly pointed out and distinctly claimed in the
concluding portion of this specification. However, both the
organization and method of operation of the invention,
together with further advantages and objects thereof, may
best be understood by reference to the following description
taken with the accompanying drawings wherein like reference
characters refer to like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, and
to show how the same may be carried into effect, reference
will now be made, by way of example, to the accompanying
drawings in which:
FIG. 1 illustrates schematically a prior art
planer design including angled lead arrangements.
FIGS. 2 and 3 illustrate schematically side and
top views of a zero lead cutter head arrangement for a
planer in accordance with the present invention.
9a
.. _
FIG. 4 is a more detailed side view of a planer according to
the present invention.
k
FIG. 5 is a top view of the planer of FIG.
FIG. 6 is a top view of a bottom cutter head assembly of the
planer of FIGS. 4 and 5.
FIG. 7 illustrates a hinge mounted outboard bearing housing
for quick removal and replacement of a cutter head.
FIGS. 8A-8H illustrate operation of the assembly of FIG. 7.
FIG. 9 is a side view of a quick open remote controlled
pressure plate according to the present invention.
FIG. 10 is a top view of the pressure plate of FIG. 9.
FIG. 11 is an end view of the pressure plate of FIG. 9.
FIG. 12 illustrates a modular, stackable cutter head in
accordance with the present invention as slidably mounted on the
shaft of a cutter head assembly, but without cutter blades mounted
thereon.
FIG. 13 is an axial view of a cutter head module of FIG. 12
~~.~~4a~
showing cutter blades mounted thereon.
FIG. I4 is an edge view of the cutter head module of FIG. 13
as taken along lines 14-14 of FIG. 13, but without cutter blades
mounted thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the present invention is a planer
including a zero lead relationship between the cutter heads and the
l0 article to be cut to improve stability of the article against a
guidebar and thereby reduce defects caused during the planing
processing. Also, the preferred embodiment of the present
invention includes features improving production capacity by
reducing time and effort required to change cutter heads and deal
with jammed or oversized boards. Overall, the present invention
provides sustained production capacity by avoiding or reducing down
time and by avoiding product downgrading and devaluation resulting
from planer related defects.
FIGS. 2 and 3 are side and top schematic views, respectively,
of a planer according to a preferred embodiment of the present
invention. In FIGS. 2 and 3, infeed roller pairs 46 and 47, roller
pair 46 including an upper roller 46a and a lower roller 46b and
roller pair 47 including an upper roller 47a and a lower roller
47b, capture a board 48 (FIG. 3) between upper and lower members of
each pair. In the view of FIG. 3, upper rollers 46a and 47a rotate
11
in the counterclockwise direction while lower rollers 46b and 47b
rotate in the clockwise direction. Accordingly, board 48 moves
rightward, in the view of FIG. 3, along a feed direction 49. A top
cutter head 50 and bottom cutter head 51 downstream from roller
pairs 46 and 47 cut top and bottom surfaces, respectively, of board
48. Top cutter head 50 rotates clockwise in the view of FIG. 3
while bottom cutter head 51 rotates counter clockwise in the view
of FIG. 3. Thus, cutter heads 50 and 5I apply leftward, in the
view of FIGS. 2 and 3, forces opposing the feed direction 49. Top
cutter head 50 is opposed by a main bed plate 52 and bottom cutter
head 51 is opposed by a pressure plate 53. Right and left side
cutter heads 54 and 55, respectively, downstream from cutter heads
50 and 51, complete the planing process by cutting the side
surfaces of board 48. Finally, an outfeed roller pair 56,
individually upper outfeed roller 56a and lower outfeed roller 56b
pull the board through the cutter heads and propel the board 48 out
of planer 10.
Referring now to FIG. 2, under the present invention the
r
parallel axes of rotation 57 for the roller pairs 46 and 47 are
normal to the centerline 58, the guidebar 59 is parallel to a datum
line 60 angled slightly with respect to centerline 58, and the axes
of rotation 61 for cutter heads 50 and 51 are normal to the datum
line 60. In this manner, the feed roller pairs 46 and 47 drive
board 48 into the face 59a of guidebar 59. Because the axes of
rotation 61 for cutter heads 50 and 51 are normal to the guidebar
12
- . ' _.
face 59a, however, force_vectors developed upon impact of cutter
heads 50 and 51 with board 48 are generally longitudinal relative
to board 48 and do not kick board 48 laterally away from face 59a
of guidebar 59. Finally, the axes of rotation 56c for outfeed
roller pair 56 are also normal to the datum line 60, and therefore
normal to the guidebar face 59a. In this manner, outfeed roller
pair 56 pulls the board longitudinally along guidebar 59 without
introducing any lateral forces relative to the face 59a of guidebar
59.
Planers are traditionally manufactured with one centerline
defining the orientation of axes of rotation for major rotating
components, i.e., infeed and outfeed roller pairs and cutter heads.
Modification to such traditional planer arrangements under the
present invention requires an additional reference line, i.e.,
datum line 60. To minimize alteration of traditional planer
design, it is suggested that the mounting assemblies (not shown)
for cutter heads 50 and 51 include adjustment to provide a normal
relationship between axes of rotation 60 and 61 and the datum line
60, i.e., angular positioning to set the axes of rotation 60 and 61
normal to the face 59a of guidebar 59. In this manner, the cutter
heads 50 and 51 engage the board 48 with a zero lead relationship
and, therefore, do not introduce force vectors kicking board 48
laterally away from guidebar 59. To establish such zero lead
relationship, it is suggested that the mounting of the cutter head
assemblies be established with slightly oversized mounting holes.
13
._
In this manner, prior to securing the cutter head assemblies to the
planer frame by tightening of mounting bolts, the cutter head
assemblies can be slightly rotated relative to the frame to
establish the desired zero lead relationship between cutter heads
50 and 51 and datum line 60.
While shown herein as a zero lead relationship between the
axes of rotation 60 and 61 relative to the guidebar face 59a, it
may be desirable to provide a reverse angled lead relationship
between the axes of rotation 60 and 61 and the face 59a of guidebar
59. Under such reverse angled lead relationship, force vectors
developed upon impact of cutter head blades with the board include
transverse components directed into the face 59a of guidebar 59.
In other words, an angled relationship opposite that of the infeed
roller pairs 46 and 47. Both the infeed roller pairs 46 and 47 and
the cutter heads 50 and 51 would then urge the board against the
face 59a of guidebar 59. In this manner, planer 10 produces no
force vectors urging the board away from the face 59a of guidebar
59. In contrast, traditional planer design pits the lateral force
vectors developed by the infeed rollers against lateral force
vectors developed by the cutter heads, and as a result board
instability relative to the guidebar exists in traditional planer
design.
FIGS. 4 and 5 illustrate in more detail side and top views,
respectively, of a planer 70 according to a preferred embodiment of
14
~~~~~~
the present invention. Planer 70 includes infeed roller pairs 72
according to conventional design. In particular, the axis of
rotation 74 for each roller of roller pairs 72 is normal to the
centerline 76 of planer 70. In accordance with normal operation of
such devices, roller pairs 72 force a wood article along a feed
direction 77 through planer 70. As discussed above in connection
with the schematic illustration of a planer in FIGS. 2 and 3, the
guidebar 71 of planer 70 has an angled lead relationship to the
axis of rotation 74 for each roller of roller pairs 72, i.e.,
guidebar 71 is angled relative to centerline 76 to allow roller
pairs 72 to drive a board into guidebar 71.
Planer 60 further includes a top cutter head assembly 78 and
a bottom cutter head assembly 80. Generally, cutter head
assemblies 78 and 80 are mountable upon planer 70 in conventional
fashion, but include adjustment, e.g., oversized mounting bolt
holes, to establish a given angular relationship, e.g., zero lead,
between axes of rotation 78a and 80a, respectively, relative to the
datum line 76. As previously discussed, such adjustment in angular
relationship between the axes of rotation 78a and 80a establishes
appropriate force vectors on a wood article along the guidebar 71
rather than laterally away from guidebar 71.
FIG. 6 illustrates separately the lower cutter head assembly
80 including a drive motor 82 coupled to a cutter head support
shaft 90, the axis of shaft 90 defining the axis of rotation 80a
for cutter head assembly 80. In FIG. 6, the shaft 90 is supported
at its distal end 90a by an outboard bearing housing 92. The
bearing housing 92, typically weighing on the order of 80 to 90
pounds, receives the distal end 90a of shaft 90 within a grease
locking sleeve 94. The distal end 90a of shaft 90 and sleeve 94
are cylindric and closely dimensioned to closely hold the shaft 90
in its desired position during operation of planer 60. Bearing
housings can be difficult to mount on shaft 90 due to the close
cylindric dimensioning between sleeve 94 and distal end 90a of
shaft 90 establishing a requirement of strict co-axial movement
when mounting.
In accordance with the present invention, however, housing 92
is carried on an articulated hinge assembly 96. Hinge assembly 96
maintains bearing housing 92 at a given elevation, i.e., supports
the weight of housing 92 at a specific height, whereby the operator
merely co-axially aligns the housing 92 for mounting on the shaft
90. The hinge arrangement 96 thereby greatly reduces operator
effort required to mount housing 92 on shaft 90. Prior mounting
arrangements would require the operator to manually hold the weight
of housing 90 with great difficulty in aligning the sleeve 94 co-
axially for mounting on the shaft 90.
FIG. 7 illustrates in more detail the hinge arrangement 96 and
its support of bearing housing 92 for mounting on the distal end
90a of shaft 90. FIGS. 8A-8H illustrate successive steps in the
16
~~~~4~~'
dismounting of housing 92 from shaft 90. In FIG. 7, housing 92 is
shown dismounted from shaft 90. Bearing housing 92 and sleeve 94
are generally of conventional design, except housing 92 includes a
mounting flange 98 defining a pivot point 100. A first hinge link
102 pivots at the pivot point I00 and at a pivot point 104. A
second link 106 pivotally couples to the link 102 at the pivot
point 104 and at its proximal end pivotally mounts at a pivot point
I08 of mounting flange 110 fixedly mounted, e.g., by way of bolts
112 to the frame 114 of cutter head assembly 80. Thus, the
articulated nature of the hinge arrangement 96 allows co-axial
alignment of the cylindric sleeve 94 and the cylindric distal end
90a of shaft 90 whereby bearing housing 92 may move easily under
manual mounting along the axis 80a of shaft 90 for mounting
thereon.
I5
FIGS. 9-11 illustrate a pressure plate 120 maintaining a
selected magnitude pressure against an article following planing by
the top cutter head assembly 78 and during cutting by the bottom
cutter head assembly 80. Prior pressure plate assemblies
maintained a fixed spacing between the pressure plate and the
bottom cutting head. In some cases, cam mounted top pressure
plates allowed an operator to quickly, but manually, move the
pressure plate upward to accommodate an oversized or jammed wood
article. Thus, under prior planer designs, the operator manually
manipulates the top pressure plate upon occurrence of oversized or
jammed wood articles. As may be appreciated, the need for an
17
2i3~~~
operator to enter the planer room and manually deal with a jammed
board contributes to system down time, and therefore loss of
production and loss of money. Furthermore, anytime an operator
enters a planer room there exists a risk of injury to the operator
in proximity of such equipment.
In FIGS. 9-11, the pressure plate arrangement of the present
invention establishes a given spacing between pressure plate 120
and the cutter head of the bottom cutter head assembly 80. Such
spacing, however, is not fixed absolutely. In particular, the
pressure plate 120 of the present invention maintains sufficient
magnitude pressure against a wood article to maintain such wood
article appropriately against the cutter head 80, but can
accommodate a jammed or oversized wood article by upward movement
in response thereto.
Pressure plate 120 enjoys vertical freedom of movement by
mounting to a vertically movable pressure plate mounting bracket
124. Bolts 126 attach plate 120 to mounting bracket 124. Mounting
bracket 124 slides vertically relative to a front mounting plate
128. Front mounting plate 128 is stationary relative to the body
of the pressure plate assembly. More particularly, bolts 130 mount
the front mounting plate 128 to the top cutter head yoke via
mounting brackets 131. Mounting bracket 124 includes an upstanding
plate portion 124a. Plate 124a is captured slidably, i.e.,
vertically slidably, between the front mounting plate 128 and a
18
pair of left and right guide elements 140. Spacer elements 142
(one shown in cross-section at the broken-away portion of FIG. 10)
provided between guides 140 and front mounting plate 128
accommodate the thickness of plate 124a and allow vertical movement
of plate 124a, and therefore vertical movement of the mounting
bracket 124 and pressure plate 120.
A crank assembly 150, including a handle 152 for rotating a
shaft 154, accomplishes vertical positioning of the plate 120.
Shaft 154 carries worm gears 155 which turn lifting screws 160
coupled, as described hereafter, to plate 124a. Thus, by operation
of the handle 152 the pressure plate 120 achieves a given vertical
clearance between the cutting head of lower cutting head assembly
80 and the pressure plate 120.
Mounting screws 160 couple to the mounting bracket plate 124a
by way of air pressure operated pneumatic actuators 170. Pneumatic
actuators 170 allow a given magnitude vertical movement between
screws 160 and plate 124a, e.g., one-half inch. By regulating the
amount of pressure applied to pneumatic actuators 170 a given
magnitude biasing force may be employed in maintaining the pressure
plate 122 against a wood article. Thus, by selectively adjusting
the magnitude of air pressure applied to actuators I70, actuators
170 accommodate jammed or oversized wood articles without bringing
the entire planing operation to a halt. Under such conditions
where a jam does occur, however, the operator may operate the
19
_ ~~:~44~2 : _
actuators 170 remotely to raise pressure plate 122 by, for example,
one-half inch to accommodate such oversized or jammed wood articles
and then re-engage actuators 170 to return immediately to operation
of the planer. As may be appreciated, down time is reduced by
avoiding the requirement of direct manual manipulation of a
pressure plate to relieve jammed or oversized wood articles and
operator safety is maintained by virtue of the remote operation of
actuators 170.
l0 Pressure plate 120 further includes a pneumatic actuator 180
driving a locking arrangement 190 for selectively locking the
mounting bracket plate 124a in position against the front mounting
plate 128. In particular, a bolt 192 is fixedly attached to the
piston rod 194 of actuator 180. Bolt 192 passes through a
vertically slotted aperture 196 of front mounting plate 128 and
through a cylindric, close fitting aperture in plate 124a. Thus,
by drawing the bolt 192 toward actuator 180 the plate 124a is held
by friction against the front mounting plate 128. In this manner,
the pressure plate 120 may be maintained in a given vertical
position, i.e., may be locked in position by operation of actuator
180. The slotted aperture 196, however, does permit some vertical
movement of the locking arrangement 190 in response to an oversized
wood article or jammed condition. The plate 120 can move
vertically to some extent under such extreme, i.e., non-normal
operation, conditions. If the pressure plate 120 does encounter an
oversized or jammed wood article, the magnitude of downward force
~~~~~~~
applied to the plate 124a by actuators 170 should be sufficient to
overcome friction between the plate 124a and front mounting bracket
128 established by actuator 180. Thus, the pressure plate
arrangement can survive an abnormal operating condition, i.e.,
oversized article or jammed article, and return to normal operation
without interrupting work flow. If the system does not
automatically handle such abnormal conditions, the operator need
only remotely release the actuators 170 and 180 momentarily to
clear the feed path and thereby remotely resolve any such abnormal
condition and immediately return to operation.
In FIG. 9, a remote operator control room 200 includes release
switches 202 and 204 for remote operation, i.e., release of air
pressure, of the actuators 170 and I80, respectively. Control room
I5 200 may further include air pressure regulation controls 206 and
208 for remote manipulation of air pressure applied to the
actuators 170 and I80, respectively.
With reference to FIG. 12, planer operation is improved by use
of a modular, stackable cutter head 220 comprising individual
cutter modules 222. Each module 222 mounts slidably upon a cutter
assembly shaft 224 driven by a cutter head assembly motor 226.
Each module 222 is locked in position upon shaft 24 by means of a
grease locking sleeve 228. The distal end of shaft 224 is
supported upon a bearing housing 92 as described above, i.e., with
housing 92 supported upon an articulated hinge (not shown in FIG.
21
~I~4~0~
12). The longitudinal dimension, i.e., width as seen in FIG. 12,
of each module 222 is 3 1/4 inches and modules 222 receive cutter
blades (not shown in FIG. 12) of slightly wider dimension, e.g., 3
1/2 inches. By providing radial offset between adjacent modules
222, the blades mounted upon modules 222 may be overlapped to some
extent, e.g., 1/8 inch, to provide continuous blade presentation to
the board surface.
As may be appreciated by those skilled in the art, the modular
to aspect of the cutting head 220 supports quick dismounting,
especially in conjunction with the articulated hinge mounted
bearing housing 92, and therefore supports rapid cutter head change
over during brief planer shutdown intervals.
FIG. 13 illustrates an end view of one module 222, including
cutter blades 230 mounted thereon. Each blade 230 is attached to
the body of module 222 by means of counter sunk screws 232 and
screw holes 234. Relative position between the modules 220 is
established by a set of six apertures 240 equa-angularly
distributed about each module 222. By mounting the modules 222 I
upon shaft 224 and aligning selected ones of the apertures 240, a
selected angular offset between adjacent blades 230 may be
established. The apertures 240 are suitably aligned and pins 242
are placed through aligned apertures 240 for securing the
established relative radial positioning of modules 222. To mount
the cutting head 220, the first module 222 is placed on shaft 224
22
fJ
and locked in position by means of grease locking sleeve 228. Pins
242 are then positioned in the apertures 240 of the first module
222. The second module 222 is then slidably positioned on shaft
224 adjacent the first module 222, with its apertures 240 receiving
the pins 240 as mounted in the first module 222. Once the second
module is so positioned, its grease locking sleeve 228 is engaged
to lock its position on shaft 224. This process continues until a
desired number of modules 222 are mounted on shaft 224. The pins
242 remain in place during operation and act as a backup retention
mechanism for the cutter head 220. In particular. if one of the
modules 222 should become loose, i.e., by loss of pressure in
sleeve 228, the pins 242 remain in place to secure module 222
position by virtue of the adjacent fixedly attached modules 222.
Important features of the stackable cutter head 220 are the
longitudinal overlapping of knife blades 230 and the fact that each
module 222 of the stackable cutter head 220 may be manually handled
by one individual, i.e., each module 222 is on the order of 80
pounds, so as to avoid the need, and requirement under government
safety standards, that a crane be used for articles of weight
greater then, for example, 8o pounds. The interlocking pins 242
establish selected radial offsets between adjacent heads and
thereby allow a longitudinal overlap between adjacent knives.
Other advantages include, by nature of the modularity, an ability
to swap damaged modules 222 or cycle different modules 222 out to
heavy wear portions of the head 220 to achieve more uniform wear of
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knife blades 230. Also, the stackable cutter head modules 222 are
interchangeable from top cutter head to bottom cutter head. Thus,
the individual modules 222 are all the same and can be maintained
in a given inventory without maintaining separate parts for
separate top and bottom cutter head assemblies. This allows
switching and swapping of parts and more complete use of each
component. Also, localized damage to a portion of a stackable
cutter head results in damage to only one component, and therefore,
a much reduced cost of repair or replacement, i.e., need to only
replace one module 222 not the entire cutter head or an entire
knife.
Thus, where a traditional planer would have the cutter head
more permanently mounted upon the shaft and require dismounting of
the entire shaft, cutter head, and bearing housing to accomplish
cutter head change over, the present invention proposes that
individual components of the cutter head be individually
replaceable, and by manual operation without the aid of a crane,
for more rapid cutter head change over, and therefore more
efficient overall production when cutter head change over is
required during planer operation. When the blades of a cutter head
require replacement, a traditional cutter head would, for most
efficient operation, require that the blades be individually
dismounted from the cutter head and replaced or sharpened. Under
the present invention, however, the entire cutter head is more
easily and more quickly removed then removing individual cutter
24
head blades. Accordingly, under the present invention one cutter
head module 222, or set of modules 222, may be quickly removed when
blades become dull or damaged and replaced with a new cutter head
module 222, or set of modules 222.
It will be appreciated that the present invention is not
restricted to the particular embodiment that has been described and
illustrated, and that variations may be made therein without
departing from the scope of the invention as found in the appended
claims and equivalents thereof.
