Note: Descriptions are shown in the official language in which they were submitted.
FLEXI BLE PLAT~N PLANER
_ackground of the Inventio
Field of the Invention
The present invention relates to lumber planing
devices of the two-way thicknessing type which plane a piece of
lumber on two opposite sides to produce a smooth finished piece
of a predetermined thickness~
Description of the Prior Art
A typical prior art device for planing both sides of a
rough sawn piece oE lumber has an infeeding mechanism Eeeding
the workpiece across a lower platen which supports it as it
travels beneath an upper planing head which surfaces the top of
the workpiece~ The workpiece then continues on toward a lower
planing head which surfaces its bottom. If ~he workpiece is not
: held up against an overhead plate, too much may be planed off
the lower surface of the workpiece or the lower surface may be
planed only in intermittent patches. Up to now, the only way to
avoid ~hese occurrences, both of which will adversely affect the
grade of the lumber, was to hold the workpiece against an upper
platen as it moves over the lower planing head by a hinged end
portion of the lower platen which is urged upward by pneumatic
or other means.
However, the provis.ion of a hinged segment on the
lower platen is in itself a source of problems. First, the
hinge creates a crevice in which splinters and pitch accumulate
causing the workpiece to bend and stick as it passes over the
lower platen. Accumulated debris also interEeres with the
setting of the desired lower to upper platen distance~ resulting
in inaccuracy in the dimensions of the fini.shed product.
Furthermore, the debris can scratch the lower surface of a
workp.iece~ reducing the grade of lumb~r produced from it.
Another problem associated with a hinged ancl segmented
lowPr platen is exce~ive wear caused by platen ch~tter as
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uneven portions of a workpiece move over the hinged segment,
causing its parts to rattle and impact against one another.
This also results in a~l undesirable noise level. Furthermore,
horizontal deflection of the lower platen, causing shifting of
the workpiece and strain on the lower platen, results from the
hinged mounting of the lower platen~
Summary of the Invention
The present invention provides a planing device in
which the problems inherent in prior art segmented platen
devices are eliminated, resulting in a smooth operating, quiet,
and highly accurate planer, which will produce the maximum
number of full thickness boards possible. The invention has, in
place of a hinged and segmented lower platen, a flexible and
continuous lower platen which is cantilevered from the frame of
the planing ~pparatus. The platen has its end flexed upward by
a pneumatically actuated lever, and cooling means are provided
on the end o~ the platen to dissipate heat due to Eriction
between the lower platen and workpiece.
The novel structure eliminates the problem oE debris
accumulation and the inaccuracy caused thereby. The invention
has increased durability, since the resiliency oE the lower
platen allows it to respond to unevenness in a workpiece without
a rattling and impacting of parts against one another, thus
eliminating the excessive wear and noise caused by platen
chatter. Horizontal deflection of the lower platen is
eliminated by the can-tilevered mounting of the platen, ensuring
an accurate and smooth finish on a workpiece.
The invention essentially provides an appara~us Eor
holding a workpiece against a fixed platen during surEace
treatment of one side thereoE by a surEace treatment element
spaced a first predetermined distance from said fixed platen
comprising an elonga-ted body having a workpiece contact surface
extending parallel to said fixed platen and adjacent said
surface treatment element; means connected to one end portion of
said elongated body remote from saicl surface treatment element
for locating the workpiece contact surface a second
predetermined distance from said fixed platen. The apparatus
includes an elongate body having the other end thereof adjacent
said surface treatment element free flexing for movement
relative to said one end; biasing means connected to said free
flexing end for applying pressure thereto to bias said free
flexing end against the workpiece to maintain contact between
the workpiece and said fixed platen to accommodate variations in
the thickness of the workpiece; and means for driving the
workpiece from said one end portion toward said Eree flexing end
of said elongated body to effect surface treatment thereof.
Brief Descriptiorl of the Drawings
Fig. 1 is a side elevational view of a planer using
the present invention.
Fig. 2 is a schematic representation of the operation
of a planar using the present invention.
Fig. 3 is a side elevational view, partially broken
away, of the ~lexible platen oF the pre~ent invention.
Fig. 4 i~ a sectional view taken along line 4-4 in
Fig. 3~
Fig. 5 is a perspective view of the end of the
flexible platen.
_etailed Description of the Drawin~s
Referring to Fig. 2, a planing device using one
embodiment of the present invention has infeed rol]ers 11
feeding a workpi~ce 12 o~ a thickness indicated by the arrows 13-
13 under a chip breaker shoe 14 which holds the workpiece 12
a~ainst a steel roller 1l6O Both the chip breaker shoe 14 and
the steel roller lfi are adjustable in a vertical direction as
indicated by arrows.
The worlcpiece 12 then passes over a platen 17 while
its top surface i5 planed by an upper planing head 18 oE a
conventional type. The upper planing head 18 will remove a
predetermined thickness indicated by the arrows 19 19 from the
top of the workpiece 12, which will then pass under an upper
platen 21 which is adjustable in a vertical direction relative
to the lower platen 17; as indicated by the arrow. A lower
planing head 22 of a conventional type will remove a thickness
from the bottom of the workpiece 12 indicated by the arrows 23-
23. If the workpiece has a sufficient initial thickness, theresulting product will be a board smooth on both sides and
having the desired predetermined thickness indicated by the
arrows 24-24.
In the present invention, the lower platen 17 is
Elexible at the end near the lower planing head 22, and can flex
upward in the direction indicated by arrow 26 to hold the
workpiece 12 firmly against the upper platen 21. This flexing
is shown in exaggerated form in Fig. 3. If the initial
thicknecss of the workpiece 12 is insufficient, the workpiece 1~
will be held against the upper platen 21 by the lower platen 17,
thus resulting in a finished product having the m~ximum possible
thickness. In some cases, a woxkpiece 12 will be rough and
thick enough for the lower planing head 22 to partially plane in
intermittent patches, but the workpiece 12 will remain rough on
the bottom side. However~ a finished product of full thickness
with some roughness on one side is preEerable to one which is
smooth huk too thin. Thus, the flexible platen of the present
invention results in the optimal planing of each workpiece.
Referring now to Figs. 1, 2 and 3, the invention will
be described in more detail. The lower platen 17 and adjacent
mechani~3ms are covered by a housing 20 to protect the machinery
and to prevent the escape of wood chips and dust into the
workplace. Out~3ide oE the housing are the infeecl rollers ll
which include, instead oE one continuous upper roller, three
upper rubber rollers arranged side-by-side and powerecl by
conventional means. The use of a resilient material like
rubber, as well as the use of three rollers rather than one
continuous roller, accommodates rough or bent workpieces without
cracking or splitting them. The lower infeed rollers, which are
idle, also include three side-by-side rubber rollers. Inside
the housing 20 i9 a chip breaker shoe 14, to which the infeed
rollers 11 ~eed the workpiece 12, of a conventional type known
in the art. The chip breaker shoe 14 serves the Eunction of
holding the workpiece 12 firmly down as it passes under the
upper planing head 18, as well as en~uring that the workpiece 12
does not split as its upper side is planed
Prior to being planed by the upper planing head 18,
the workpiece 12 moves onto the lower platen 17. The lower
platen 17, from its Eirst end near the upper planing head 18 to
its opposite end adjacent the lower planing head 22, is one
continuous piece which, for most app:Lications, will have a width
of between 6 to 1~ inches and a length of about four feet. The
lower platen 17 is mounted on a platen frame 27 by bolts 28 only
at the end near the upper planing head 18, leaving the opposite
end cantilevered from the frame. This cantilevered portion 29
is about 18 inches long and is thin enough to ensure adequate
flexibility. Typically~ the cantilevered portion 29 will be
about two-thirds inches thick, compared to about one and one-
third to one and two-fifths inch thickness for the rest of the
lower platen 170 The top surface of the lower platen 17
preferably will be plated witll industrial hard chrome, and the
tip oE the cantilevered portion 29 will have a carbide insert
31, to protect against excessive wear.
As is best seen in Fig. 5, mounted to the unclersicle oE
the lower platen 17 a-t the tip of the cantileverecl portion 29 is
triangular tube 32 closecl at both ends which can ba Eormed,
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for ~xample, from an angle iron. A block 35 welded to the
e~terior of tube 32 near its vertex runs the length of khe
triangular tube 32, and an inlet pipe 33 inside the triangular
tube 32 extends substantially the length of the tube 32 and
through one end wall. To cool the edge of the lower platen 17,
coolant fluid such as a glycol/water mixture is pumped in
through the inlet pipe 33, and exits through a suitable outlet
opening 34 in the triangular tube 32. Since a planing device
using the present inventicn will typically process 120G board
feet per minute, the cooling system is utilized to prevent
damage to lumber and equipment from frictional heat buildup in
the platen~ The use of parallel inlet and outlet fluid flow
passages across the width of the lower platen 17 provides
subs~antlally even cooling, eliminating the warpage which uneven
cooling may cause.
The height of the lower platen 17 can bQ adjusted in a
diagonal direction indicated by arrows in Fig. 2. Diagonal
adjustment is preferred over vertical adjustment to maintain
proper clearance between ~he tip of lower platen 17 and the
curved lower planing head 22. Pairs oE interlocking wedges with
diagonal edges parallel to the direction of movement of the
lower platen 17 are used in the adjusting of lower platen
height. The platen ~rame 27 includes on each side a vertical
side support 36 near the ends of which a pair of upper wedges 37
and 38 are mounted. The main frame 39 of the planing device has
corresponding lower wedges 41 and 42 on each side.
As seen in FigO ~ I upper wedge 38 has on its outside
face a groove 43 parallel to the direction oE movement of the
lower platen l7, which receives a ~lange 44 on the inner face of
a locking plate 46 having a width less than that of the groove
43. Lower wedge 42 has on its outside face a groove 47 parallel
to the groove ~ in the upper wedge 38. While the groov~ ~l4 in
the upper wedge 38 has a rectangular cross ~ectionl the groove
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P~
47 in the lower wedge 42 has a trapezoidal, or wedge-shaped,
cross section, with the sidewall nearer the upper wedge 38
sloping downward and back from the outside face oE the lower
wedge 42. The trapezoidal groove 47 receives a correspondingly
wedge-shaped flange 48 on the inner face of locking plate 46~
When the wedge-shaped flange 48 abuts the sloping sidewall of
the gxoove 47, inward movement of the locking plate 45 brings
the flange 44 into abutment with the sidewall of yroove 43
nearer the lower wedge 42. The two flanges 44 and 4B th~n serve
to hold the upper wedge 38 and lower wedge 42 together in a
longitudinal clirection. A flange 4g extending upward from the
inner face of the lower wedge 42 engages a mating slot 51 in the
adjacent lower edge of the upper wedge 38 to keep the two wedges
properly positioned in the lateral direction. It will be
understood, of course, that the wedge structure on the opposite
side of the platen may be identical.
A rod 52 which i5 threaded at both ends extends
transverse to the lower platen 17 through the locking plate 46
and lower wedge 42, and through an identical lower wedge 53 and
locking plate 54 on the opposite side of the platen 17. A nut
55 is secured to one end of the rod 52 by a cotter pin 56 and is
provided with a washer 57 which may be welded or otherwise
affixed thereto. The nut is locked against rotational movement
relative to the plate 54 by means of a pin 58 which extends
through the washer 57 and into the locking plate 54. The other
end of the rod 52 is threadedly engaged with an extension 59 to
which a handcrank may be attached. The handcrank, or any other
means commonly known, can be used to rotate the extension 59~
which abuts against the lockiny plate 46, to clamp the locking
plates 46 and 54 into engagement with the correspondiny upper
and lower wedges with the desired deyree of pressure in a wel.l
known manner.
q~
The height of lc>wer platen 17 is ad~usted by first
rotating the extension 59 on rod 52, and the identical extension
60 associated with wedges 37 and 41, with a handcrank or other
means to loosen the locking plates. The upper wedges are then
free to slide diagonally upon the lower wedges. Using a
handcrank or othex power source, the operator then rotates a rod
61 extending frc~m a worm 62 meshed with a pinion 63. This
causes rotation of a threaded rod 64, coupled with the pinion 63
for rotation therewith in any well known manner, within a
threaded bore 66 extending from the platen frame 27 parallel to
the direction of movement of the platen Erame. Since the
threaded bore 66 is affixed to the lower platen frame 27,
rotation of the rod 64 therein will effect cliagonal movement of
the lower platen 17. When the lower platen 17 is in the desired
position, the locking plates ars tightened against the we~dges by
rotation of the extensions 59 and 60v to lock the platen 17 in
position.
Extending from the side support 36 of the platen frame
to an identical support on the opposite side of the platen 17
are transverse beams 67, 68, 69 and 70 which serve to add
rigidity and strength to the platen fxame ~7. The numb~r of
beams can be varied according to the structural needs of a
particular embodiment of the invention. An air bag 72 is
mounted on the side of beam 67 nearest the end of the lower
platen 17, which is about ten inches from th~ end of the lower
platen 17, and can be pressurized through an air line 71
connected to a conventional source of pressurized air well known
in the art, for a purpose described below.
Pivoted from each side support oE the platen frame 27
is a V-shapecl lever 73 extending downward from the pivot point
74 and then turning diagonally upward toward the end of the
lower platen 17. Lever 73 and an iclentical lever on the
opposite side of the Erame are connected at their lowest points
a
73
by a crossbar 75 ad~acent a contact plate 79, afEixed to the air
bag 72 in a conventional manner, against which the air bag 72
expands when pressurized, and at their distal ends by a second
connecting crossbar 75 abutting against block 35 which may be
welded or otherwise affixed to the angle iron 32. When the
device is in use, the air bag 72 is pressurized through the air
line 71 and expands against the contact plate 79, exerting
pressure on the crossbar 75 to urge the levers upward. The
second crossbar 76 pushes upward against the block 35, tending
to deflect the end of the lower platen 17 upward. In Fig. 3,
the deflection of the lower platen 17 is shown in phantom. For
clarity, this flexing movement is exaggerated in the drawing; in
actual use, a maximum platen flexure of about l/8 inch measured
in the verticcnl direction is sufficient. The pressurized air
bag has sufficient resiliency to absorb the force of downward
deflection of the lower platen 17 when a thick or rough
workpiece 12 passes over it.
On either side of the leve!r 73 near its pivot point 74
are adjustable ~tops 77 and 78 limiting its range oE travel.
The stops 77 and 78 include plates 81 and 82, respectively,
extending down from the platen frame 27 and having set screws 81
and 82~ respectively engaged therethrough for blocking movement
of the lever 73. An identical pair of stops limits the movement
of the lever on the opposite side of the device. The first stop
77 limits the extent oE upward pivoting of the lever 73 to
prevent the platen 17 from flexing to such a degree that it is
permanently bent or cracked, while the second stop 78 limits
backward pivoting of the lever 73 to prevent the tip of the
lower platen 17 from hitting the lower cutting head 22 if an
exceptionally thick workpiece 12 were to pass over the lower
platen 17.
In operation, the height oE the lower platen 17 i3 set
in the manner described above, and the height oE the chip
breaker shoe 14, upper planing head 18 and upper platen 21 are
adjusted by means well known in the art.
Rough lu~ber workpiece~ 12 are then fed sequentially
between the infeed rollers 11. As one workpiece 12 exits the
inEeeding rollers 11 and passes onto the lower platen 17, the
workpieces which follow it through the infeed rollers 11 will
push it through the planing device.
As the workpiece 12 passe~ under the upper planing
head 18, its top surface will be planed smooth, with the chip
breaker shoe 14 bearing down on the workpiece 12 to prevent
splitting of the wood. The workpiece 12 then passes under the
stationary upper platen 21. Unevenness in the bottom surface of
the workpiece 12 is accommodated by the flexibility of the
cantilevered portion 29 of the lower platen 17, ~hich allows
portions of the workpiece 12 of greal:er thickness to urge the
free end of the lower platen 17 slightly downward against the
pressure of the air bag 66. The wor)cpiece is thus held against
the upper platen as it progresses. 'rhe workpiece 12 passes from
the lower platen 17 over the lower p.Laning head 22, which
surfaces the bottom side, ana then exits the housing 20~
Workpieces having a thickness lass than the target thickness
after the upper side is planed will be likewise held against the
upper platen 21 by the deflected lower platen 17 and pas~ over
the lower planing head 21 without having their lower sides
planed. Workpieces of a thickness about equal to target
thickness after their upper sides are planed will have their
lower qides planed only to the degree possible while maintaining
desired thickness.
Concurren-tly with the feeding of workpieces through
the planer, coolant is circula-ted through the tube 3? and inlet
pipe 33 from a reservoir not shown by conventional means.
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While the invention has been described with reference
to a preferred embodiment, variations are possible without
departi.ng from the scope of the invention.
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