Note: Descriptions are shown in the official language in which they were submitted.
I
1 DRIVE FOR VERTICAL EDGER
BACKGROUND OF THE INVENTION
The present invention relates to vertical edger
machines used in sawmills, and in particular to improvements
in a saw blade drive for a vertical edger machine.
Typically, a vertical edger is located in a
sawmill line immediately ahead of the large circular head
saw. The vertical edger includes two vertically spaced
circular saw blades that cut horizontally into the face of
the log in order to produce the narrow edges of a board or
plank. The trailing head saw then severs the edged plank
from the remainder of the rough tree stock. A sawyer controls
the vertical spacing of -the saw blades as required for the
particular board dimensions being cut. A vertical edger may
optionally carry three vertical spaced circular saws in
order to cut edges for two vertically s-tacked boards
simultaneously.
Vertical edgers commonly include a support frame
on which is mounted a motor drive unit and appropriate
controls. The motor drives an elongated vertical shaft upon
which either two or three saw blade assemblies are slid ably
mounted. In order to vary the size of the boards produced,
a separate hydraulic or mechanical placement arm individually
slides each saw blade assembly axially along the length of
the rotating drive shaft.
Heretofore, vertical edger saw blades have been
mounted upon the drive shaft by a hub assembly. The
assembly permits the saw blade to rotate with the shaft
and permits the blade to be slid vertically along the length
of the drive shaft by the placement arm. Typically with
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1 such an assembly, the drive shaft includes a kiwi that
extends along its length. An elongated 9 rectangular key
is fixed therein. Each saw hub also includes a mating
kiwi or slot on its central opening. ennui mounted on
the shaft, the hub may slide along the shaft and key, while
the key forces the hub to rotate with the shaft.
For a vertical edger machine to operate correctly
the say blades must be rigidly maintained in a horizontal
plane. If a blade is angled or allowed to wobble on the
drive shaft the saw blade will float away from the desired
cutting line and produce inaccurate edging cuts. One problem
experienced with all vertical edgers is that after extended
use the mounting hub-shaft key assemblies become worn. This
wear permits the hub and saw blade to wobble slightly upon
the drive shaft instead of being rigidly held in a horizontal
orientation as required, resulting in inaccurate edging
cuts.
In order to correct the wobbling problem noted
above, as the hub assembly wears the vertical edger must be
taken off-line and the worn parts replaced. Normally, in
vertical edgers having a kiwi mounting arrangement, the
wear takes place on both the key and the kiwi of the saw
hub. Therefore, the key and the hubs must be periodically
replaced. The drive shaft is received in bearing assemblies
at each end. The bearing assemblies must be removed and the
saw mounting hub assemblies slid of-f of the shaft. The key
is then replaced, and if the hubs Casey show sufficient
wear the hubs are also replaced. This replacement is an
involved procedure and requires a substantial amount of down
time -for the vertical edger machine. Replacement normally
results in the loss of use of the vertical edger for an
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1 entire day.
Therefore, the need exists for a more reliable
and durable means of mounting vertical edger saw blades that
will permit rapid repair or maintenance as the saw mounting
assembly experiences wear. This mounting assembly must
provide a horizontally rigid mounting on the drive shaft,
but still allow vertical positioning of the saw assemblies
along the length of the drive shaft.
SUMMARY OF THE INVENTION
With the invention of the present application the
problems and objects described above relative to other
prior devices are alleviated.
The present invention is embodied in a vertical
edger machine that includes a saw blade drive which
provides for mating recesses spaced about the vertical
edger drive shaft and saw mounting hub. The saw blade
drive includes locking members inserted within these
mating recesses and provides for the locking members to be
urged outwardly and forwardly as the drive shaft rotates.
This outward and forward pressure locks the saw mounting
hub on the drive shaft.
As a result of the present invention, down time
for vertical edger repair is dramatically reduced, since
the machine may be maintenance while the saw mounting
hub remains on the drive shaft. Rather than loss of the
machine for an entire day, such routine maintenance can
usually be performed in a matter of minutes. This obviates
the need for an additional machine that often is used
during this periodic wear repair.
With the present device, not only does the
majority of wear take place in softer, replaceable locking
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1 members, but the load and wear is distributed over a larger
number of wear points. This permits extended use of the
vertical edger machine before repair is required.
These and other features, advantages, and objects
of the present invention will be further understood and
appreciated by those skilled in the art by reference to the
following specification, claims and appended drawings.
BRIEF DESCRIPTION OF THE DRYNESS
. _ . . . _ _
Fig. 1 is a perspective view of a vertical edger
machine embodying the present invention;
Fig. 2 is an exploded, fragmentary perspective
view of a drive shaft-mounting hub assembly embodying the
present invention;
Fig. 3 is a fragmentary, side sectional view of the
mounting hub assembly of Figure 2 with a saw blade mounted
thereon;
Fig. 4 is a bottom, plan view of the mounting hub
of Figure 2,
Fig. 5 is a bottom plan view owe the drive shaft of
Figure 2;
Fig. 6 is a fragmentary, side elevation Al view of
the drive shaft of Fig. 2; and
Fig. 7 is a fragmentary, schematic view of a drive
shaft and mounting hub interface with locking dowels inserted
therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the preferred embodiment shown in Fig. 1, a
vertical edger machine 10 is provided for use in conventional
sawmill operations. vertical edger 10 includes a support
frame 12 on which is mounted a motor drive unit 14 as well
as suitable controls (not shown. Motor drive 14 rotates a
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1 splinted, vertically oriented drive shaft 16. Slid ably
mounted on drive shaft 16 are a pair of saw assemblies 18.
Each saw assembly 18 includes a saw mounting hub 20,
Pig. 3, upon which a circular saw blade 21 is mounted.
As shown in Fig. 7, each hub 20 includes a number of arcuate
hub recesses 22 spaced about its inner surface. flub recesses
22 are spaced so that each recess lies radially opposite an
arcuate splint recess 24 on shaft 16. A cylindrical dowel
or pin 26 is received in the chamlel -formed by each hub
recess 22 and splint recess 24. Dowels 26 are held in place
by a pair of end collars 28 and 29, Fig. 2, which are secured
to either end of mounting hub 20. Hub recesses 22 and
splint recesses 24 are dimensioned so as to force dowels 26
forwardly and outwardly against hub recesses 22 as shaft 16
rotates, as described in detail below. This forward and
outward force causes hub 20 to lock rigidly onto shaft 16
and prevent wobbling of saw blade 21.
As shown in Fig. l, frame 12 is of conventional
design and includes four corner uprights 30 that are joined
by a flat, rectangular top plate 32 and a bottom plate 34.
Secured to top plate 32 is a motor support frame 36. Extending
between the lower ends of the two forward corner uprights 30
is a cross piece 38 used in mounting shaft 16.
Motor drive unit 14 is also of conventional design
and includes a motor mount 40, Fig. 1, secured to motor
support frame 36. An electric motor 42 is supported by
motor mount 40 and includes suitable controls of a conventional
type (not shown). The controls are connected with instrumentation
which allows a sawyer to manually adjust the operation of
vertical edger 10, as described below. Motor 42 is connected
by a coupling 44 to drive shaft 16. Drive shaft 16 extends
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I
1 through an upper bearing 46 down to a lower bearing 48.
Upper bearing 46 is supported on top plate 32 while bearing
48 is secured to cross piece 38. Bearings 46 and 48 can be
of any conventional type known in the art, such as ball or
roller thrust bearings.
As shown in Fig 1, upper saw assembly aye includes
a circular support bracket 60 within which saw mounting hub
20 is mounted. Support bracket 60 includes suitable bearings
which permit rotation of mounting hub 20 within bracket 60.
Bracket 60 is carried on a horizontally extending arm 62.
Arm 62 also supports a saw guard 64 of conventional design
that is used to prevent sawdust and wood chips from being
thrown out o-f the machine toward the sawyer. Guard 64 may be
interconnected with a dust removal system if so desired. A
hydraulic cylinder 66 is mounted on top plate 32 and includes
a piston rod 68. Arm 62 is connected to piston rod 68
so that cylinder 66 raises and lowers arm 62, sliding and
positioning hub 20 along the length of shaft 16. Hydraulic
cylinder 66 is of conventional design and includes suitable
controls (not shown) which allow the sawyer to accurately
position saw assembly aye on shaft 16. Although cylinder 66
is preferably a hydraulic cylinder, other apparatus could be
effectively used, such as a mechanical screw jack or the
like.
Lower saw assembly 18b is mounted upon drive
shaft 16 similarly to upper saw assembly aye, with the
exception that lower saw assembly 18b is inverted. Lower
saw assembly 18b includes a circular support bracket 70
carried on a horizontal arm (not shown), to which is attached
a saw guard I Lower saw assembly 18b is shifted vertically
along shaft 16 by a piston rod 78 and a hydraulic cylinder 76.
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1 Hydraulic cylinder 76 extends lower than cylinder 68 in
order to position lower saw assembly 18b beneath upper
saw assembly aye as is known in the art.
As shown in Fig. 1, elongated, cylindrical drive
shaft 16 has a vertically oriented, longitudinal axis.
As shown best in Figs. 2 and 5, twelve arcuately shaped
splint recesses 24 are spaced circumferential about shaft
16 and extend along substantially its entire length.
Recesses 24 form twelve raised splints 90 on shaft 16.
Splints 90 have curved outer edges, giving shaft 16 a circular
outer periphery.
Each mounting hub 20 has a generally cylindrical
body 100, Figs. 2 and 3, which is received and secured
within bracket 60. Axially offset from the median line of
hub 2Q is a radially outwardly extending circular -flange 102
that encircles cylindrical body 100. Hub 20 has an enlarged
diameter end 104 on the shorter side of flange 102. Flange
102 includes three bolt holes 105 in the surface -facing
enlarged end 104. jolt holes 105 are used in the mounting
of saw blade 21 as described below. Hub 22 has an inner
surface 106 that forms a central opening 108 through hub 20.
Central opening 108 has a generally circular periphery,
but inner surface 106 includes six arcuately shaped hub
recesses 22 spaced circumferential thereabout (Fig. 4).
Hub recesses 22 are spaced so as to be radially opposed to
alternating splint recesses 24 when hub 20 is mounted on
shaft 16, as shown in Fig. 7. Central opening 108 widens
within enlarged end 104 into a collar seating area 109,
which receives collar 28, Figs. 2 and 3. Collar seating area
109 forms an annular shoulder 110 within central opening
108. Three bolt holes 112 are used in the securing of
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1 collar 28. On the end of hub 20 opposite seating area 109
is an annular groove 113, Fig. 3, used to seat collar 29.
Dowels 26 are elongated cylindrical pins manufactured
from a material softer than either shaft 16 or hub 20.
Dowels 26 have a length equal to that of hub recesses 22 and
a diameter sufficient to be received between a radially
opposed hub recess 22 and splint recess 24 with a slight
amount of clearance to permit slid able insertion therein,
as shown in Fig. 7.
End collar 28 is a circular ring having a circular
opening 120 therethroughg Fig. 2. Opening 120 has a diameter
equal to that of the inner periphery of central opening 108.
Collar 28 has an outside diameter slightly less than that o-f
collar seating area 109 so that the collar may snugly seat
in seating area log. End collar 28 includes three bolt
holes 122 corresponding to bolt holes 112, by which collar
28 is bolted into hub 20. when bolted into collar seating
area 109, end collar 28 abuts shoulder 110 and covers hub
recesses 22. End collar 29 is a circular snap ring and has
an opening 130 with a diameter equal to that of the inner
periphery of central opening 108. The outside diameter o-f
collar 29 is equal to the outer diameter of groove 113 on
hub body 10n. Collar 29 is snapped into groove 113 and
held in place by the resilient tension of collar 29 against
hub 20.
As shown in Fig. 7, when hub 20 is mounted on
shaft 16, hub recesses 22 mate with six of the twelve splint
recesses 24 in order to for six circular channels 140
between shaft 16 and hub 20. Dowels I are received within
the circular channels 1~0 so as to lock hub 20 onto shaft
16. The diameters of dowels 26 are slightly less than those
Lowe
1 of channels 140, so that hub 20 may still slide axially
along shaft 16 with dowels 26 sliding within splint recesses 24.
Also shown in Fig. 7, channels 140 each have a
center 142 which lies outside of the inner periphery of
central opening lQ8 and the outer periphery of shaft 16.
Since the arc radius of both hub recesses 22 and splint
recesses 24 is the radius of each channel 140, these arc
radii also lie outside of the inner periphery of central
opening 108. Therefore, the arc depth of hub recesses 229
i.e. the distance between the hub inner periphery and the
deepest point of each hub recess 22, is greater than the arc
depth of splint recesses 249 i.e. the distance between the
outer periphery of shaft 16 and the deepest point of each
splint recess 24. Hub recesses 22 each circumscribe more
than 180 of dowels 26. Preferably hub recesses 22 circumscribe
in the range of 180 to 220 of dowels 26, and most preferably
circumscribe an arc of 200 about dowels 26. Preferably,
the arc depth of hub recesses 22 are in an approximate ratio
to the arc depth of splint recesses 24 ranging between 1.4
and 1.5. Most preferably this ratio is approximately 1.48.
Preferably, in a vertical edger having a drive
shaft outer periphery diameter of 2.468 and a mounting hub
inner periphery diameter of 2.471, dowels 26 will have a
diameter of .375 inches. Channels 140 will haze a clearance
around dowels 26 of between 0.002 and 0.003 inches. Center
142 of channels 140 will be offset 0.0365 inches from the
inner periphery of hub 20.
In the preferred form, shaft 16 is fabricated
from 60 Rockwell hard steel and each hub 20 is formed from
cast iron. The dowels or pins 26 are formed from bronze.
As shown in Fig. 3, saw 21 is of conventional
g
1 design and has a central aperture that fits over enlarged
end 104. A saw mounting ring 15Q is also of conventional
design and fits over enlarged end 104. Ring 150 presses saw
21 into abutment with flange lQ2. Bolts 152 pass through
ring 150 and saw 21, then into bolt holes lQ5 in flange 102.
So secured, saw 21 will rotate with hub 20.
Operation
In operation, hubs 2Q are mounted in the conventional
manner in upper and lower support brackets 6Q and 7Q. Hub
lo recesses 22 are radially aligned with six of the twelve
splint recesses 24 and six dowels 26 are received within
channels 140, Fig. 7. End collars 28 and 29 are bolted and
snapped into hub 2Q in order to hold dowels 26 in position.
As shaft 16 rotates in a counterclockwise direction
shown as arrow A in Fig. 7, splints I push against dowels
26. Since centers 142 of channels 14Q are offset from the
outer periphery of shaft 16 and inner periphery of hub 20,
splints 90 force dowels 26 forwardly and outwardly in hub
recesses 22. This causes dowels 26 to lock against hub 20
2Q at a somewhat forward location within recesses 22, shown
generally in the vicinity of arrows B in Fig. 7. This
forward and outward movement of pins 22 causes hub 2Q to
rigidly lock on shaft 16 and prevent wobbling of saw blade
21. It has been noted that if centers 142 of channels 140
lie Oil the inner periphery of central opening lQ6, then the
same locking action will not take place and saw blade 21
will haze a tendency to wobble during operation. Such wobbling
causes saw blade 21 to plane ajar from the desired horizontal
cut.
3Q After extended use the mounting elements of saw
assemblies 18 will begin to wear. Since dowels 26 are
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1 manufactured from a material that is softer than that of
shaft 16 or hub 20, the majority of such wear takes place on
dowels 26. If this wear becomes excessive dowels 26 must be
removed and replaced in order to avoid the wobbling problem
noted above. To replace dowels 26, end collars 28 and 29
are unbolted and slid along shaft 16, exposing dowels 26.
Dowels 26 are then tapped out of channels 140. New dowels
26 are inserted into channels 140 and end collars 28 and 29
are resecured to hub 20. Hub 20 is not required to be
removed from shaft 16 during this routine maintenance.
After an extensive period of operation splints 90
on shaft 16 will wear to the point that proper hub locking
action will not be experienced, even with new dowels 26.
When this occurs, collars 28 and 29 are unbolted and dowels
26 are removed. Hub 20 is then rotated about shaft 16 until
hub recesses 22 are adjacent the six previously unused
splint recesses 24. New dowels 26 may then be inserted and
end collars 28 and 29 resecured. By shifting hub 20 in this
manner the life of shaft 16 may be greatly increased. It
will be noted that in both of the routine maintenance operations
described above, hub 20 is not required to be removed from
shaft 16 and therefore may be performed with a minimal
amount of down time for vertical edger 10.
It is to be understood that the above is merely a
description of the preferred embodiment and that one skilled
in the art will recognize that various changes or modifications
may be made without departing from the spirit of the invention
disclosed herein. The scope of the protection afforded is
to be determined by the claims that follow and the breadth
of interpretation that the law allows.
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