Note: Descriptions are shown in the official language in which they were submitted.
;, . ..~1 : _.
July 14, 1994 - 1015-1627
IMPROVED CHIPPER RNIFE
BACKGROUND OF THE INVENTION
The present invention relates generally to wood processing
apparatus, and particularly to a wood chipping knife and associated
mounting assembly.
A chipper is a wood processing apparatus reducing wood
products or parts thereof to small articles referred to herein as
"chips." Chips may be produced by reducing completely a given wood
article, e.g., an entire log, or may be produced in the context of
surfacing a wood article, e.g., establishing a planar surface of a
log to be further processed such as by sawing.
Chips produced are useful byproducts. For example, chips are
often used in fiber based products such as paper. Important
characteristics of the chips produced, and establishing a value
therefor, relate to quality and ease of use in producing other
products. For example, chips are desirably of uniform size when
applied to paper making process to make consistent the paper
manufacturing process of breaking down the chips into a wood pulp.
More particularly, uniform chip thickness insures that the step of
"cooking" the wood chips for reduction to wood pulp can occur under
consistent operating conditions. Accordingly, an important
characteristic of a chipper is an ability to produce chips of
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consistent dimension.
A chipper generally comprises a disc structure rotating at
high speed and carrying thereon a set of chipper knives. The
subject matter of the present invention relates to such chipper
knives and the related mounting assembly therefor. Chips are
abrasive material, especially when presented to the high speed
rotating chipper knives. Chipper knives and associated support
structures undergo tremendous stress and wear during operation.
Accordingly, chipper knives and related support structures must
endure such abrasive conditions for as long as possible while still
producing acceptable output, i.e., while still producing
consistently dimensioned chips.
Each chipper knife includes a cutting edge and, given that a
plurality of such knives work in unison, each chipper knife edge
must be carefully aligned or calibrated in its mounting structure
to define a common cutting plane for a given set of knife edges.
In this manner, the chipper presents to an oncoming wood article a
single cutting plane and as the wood article feeds into the chipper
knives consistently dimensioned chips result.
A traditional "bent-knife" chipper arrangement carries on the
rotating disc structure a plurality of chipper knives each of
unitary construction, but presenting two cutting edges angled
relative to one another. One cutting edge provides a hogging
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function while the other cutting edge provides a planing function.
Elaborate mounting and maintenance methods and apparatus have been
developed for such unitary "bent-knife" chipping systems. A more
recent trend, however, has been use of dual-knife systems wherein
a pair of straight edge chipping knives mounted adjacent one
another in angled relation serve as a replacement for the complex
and difficult to maintain unitary "bent-knife" chipping
arrangements.
Thus, chipper maintenance can require a relatively high degree
of expertise when mounting, dismounting, and maintaining chipper
knives. Unfortunately, 'such expertise can be a limited resource in
many wood processing installations. Furthermore, the task of and
equipment required for grinding a unitary "bent-knife" is both time
consuming and expensive. Any time a unitary "bent-knife" is
dismounted for resurfacing, the processing of remounting within the
chipper head requires babbiting and precision adjustment to
establish the desired cutting plane.
Generally, dual-knife systems have as an objective a
simplified registration scheme for the knife blades, i.e.,
simplified relative to the unitary "bent-knife" chipping systems.
Also, these dual-knife systems seek to reduce the level of
expertise required in dismounting and remounting chipper knives.
In many cases, the chipper knives have two cutting edges, and the
knives are "reversible" whereby a single knife may be dismounted,
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reoriented, and remounted to present a new cutting edge. As may be
appreciated, in executing such dismounting and remounting of
knives, the resulting configuration must still present a unified
cutting plane to the oncoming wood article to maintain consistent
the chip output.
U.S. Patent No. 5,271,440 issued December 21, 1993 to Joseph
R. Bradstreet, Jr., et al, and entitled CHIPPER DISC ASSEMBLY
HAVING EXTENDED- LIFE REGRINDABLE DISPOSABLE KNIVES shows a chipper
knife assembly for a disc type wood chipper including a reversible _.
and disposable knife with a serrated surface. The serrated surface
provides predetermined registration of the knife relative to a
mounting assembly whereby disc mounting and remounting of the knife
requires little or no precision calibration to establish the
desired cutting plane among a plurality of such knives. The
chipper knife can be thereby dismounted and reground and, when
remounted, advanced along the serrated clamping surface to maintain
a desired edge position, i.e., to establish the desired cutting
plane.
U.S. Patent NOS. 4,771,718; 4,850,408; 4,997,018; and
5,271,442 issued September 20, 1988; July 25, 1989; March 5, 1991;
and December 21, 1993 to Charles T. Carpenter and Robert M. Bailey
show various forms and progressive development of a chipper disc
and knife assembly including a registrable mounting structure and
a reversible knife, i.e., a knife having two cutting edges with the
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advantage of reversibility and extending the useful life of each
knife between reconditioning, i.e., honing, thereof.
The chipper knife bears by far the majority of stress and wear
against the abrasive wood product. The supporting structure,
however, must also necessarily be exposed to the abrasive wood
product. In particular, an inclined surface of the support
structure adjacent the cutting edge of the chipper knife, referred
to as the "chip breaker", carries the chip away from the chipper
knife and completes the task of breaking the chip into desired
thickness. Accordingly, the chip breaker is necessarily exposed to
the abrasive wood product, and constitutes in all known chipper
systems a wear element. Typically, the chip breaker is provided as
a leading face of a clamp plate holding the knife in place.
Because this chip breaker is an important aspect of consistent chip
size, its wear during operation represents a source of degradation
in chip quality. Accordingly, the clamp plate comprising the chip
breaker must be periodically replaced to maintain chip consistency.
The subject matter of the present invention addresses the
above concerns in chipper knife construction and associated
supporting structure.
SUMMARY OF THE INVENTION
A preferred embodiment of the present invention in a first
aspect is a chipper knife comprising a chipper knife body having
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first and second face surfaces with at least one cutting
edge formed integrally to said body. A chip breaking
formation protruding from the body operates to complete chip
severing when the knife engages a wood article. In this
manner, the chipper knife of the present invention provides
a leading, and wearing, component of a chip breaking system
replaced upon replacement of the chipper knife.
In accordance with a second aspect of the present
invention, a chipper knife having first and second face
surfaces, a cutting edge, and a leading portion of a chip
breaking surface integral thereto and spaced from the
cutting edge is used in combination with a clamp capturing
the knife at the first and second face surfaces. The clamp
includes a following portion of a chip breaking surface
cooperative with the leading portion of the chip breaking
surface integral to the chipper knife body. Because the
leading portion of the chip breaking surface is replaceable
along with the chipper knife, the wearing component of the
chip breaking system may be periodically replaced and the
remaining portions may enjoy longer useful life.
According to another aspect of the present
invention, there is provided a chipper knife comprising: a
generally planar body defining first and second opposing
face surfaces, each face surface including a clamping
portion for mounting of said knife and an exposed portion; a
cutting surface terminating in a cutting edge; and a nose
formation integral to said planar body at said first face
surface and defining a border between said clamping portion
and said exposed portion of said first face surface, said
nose formation including an inclined chip breaking surface
directed toward said first face surface in a direction from
said clamping portion to said exposed portion of said first
face surface.
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According to still another aspect of the present
invention, there is provided a chipper knife comprising: a
generally planar body defining first and second opposing
face surfaces, each face surface including a clamping
portion for mounting of said knife and an exposed portion; a
cutting surface terminating in a cutting edge; and a nose
formation integral to said planar body at said first face
surface and defining a border between said clamping portion
and said exposed portion of said first face surface, said
nose formation including an inclined chip breaking surface
directed toward said first face surface in a direction from
said clamping portion to said exposed portion of said first
face surface; wherein said knife further comprises: a second
cutting surface terminating in a second cutting edge
opposite said first cutting edge; and a second nose
formation integral to said planar body at said second face
surface and including a second inclined chip breaking
surface directed toward said second face surface in a
direction from said clamping portion to said exposed portion
of said second face surface; wherein said knife further
comprises: a first registration structure having fixed
position relative to said first mentioned cutting edge; and
a second registration structure having fixed position
relative to said second cutting edge, each of said first and
second registration structures providing a predetermined
mounting position for said knife relative to and when
mounted to an associated clamping structure in corresponding
first and second orientations.
According to yet another aspect of the present
invention, there is provided in combination: a chipper knife
having first and second face surfaces, a cutting edge, and a
leading portion of a chip breaking surface integral thereto
and spaced from said cutting edge; and a clamp capturing
said knife at said first and second face surfaces, said
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clamp including a following portion of a chip breaking
surface cooperative with said leading portion of said chip
breaking surface to complete chip severing from a wood
article when said knife is captured by said clamp.
According to a further aspect of the present
invention, there is provided a chipper knife comprising: a
chipper knife body having first and second face surfaces; a
cutting edge formed integral to said body; and a chip
breaking formation protruding from said body and operative
to complete chip severing when said knife engages a wood
article.
According to yet a further aspect of the present
invention, there is provided a chipper knife comprising: a
chipper knife body having first and second face surfaces; a
cutting edge formed integral to said body; and a chip
breaking formation protruding from said body and operative
to complete chip severing when said knife engages a wood
article; wherein said chip breaking formation protrudes from
said first face surface and said knife further comprises: a
second cutting edge opposite said first cutting edge; and a
second chip breaking surface protruding from said second
face surface; wherein said knife further comprises: a first
registration structure for mounting relative to a clamp and
having fixed position relative to said first cutting edge;
and a second registration structure for mounting relative to
a clamp and having fixed position relative to said second
cutting edge.
According to still a further aspect of the present
invention, there is provided a chipper including a chipper
knife and mounting mechanism for releasably mounting the
chipper knife to a chipper body, said chipper knife
comprising a planar body defining opposed parallel face
surfaces and opposed parallel edge surfaces, said edge
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surfaces angled relative to said face surfaces whereby one
edge surface forms an acute angle with one face surface and
the other edge surface forms an acute angle with the other
face surface, said acute angles forming sharp cutting edges
at opposite faces of the knife whereby the knife can be
inverted to exchange the positions of the cutting edges and
provide the same profile configuration, and a registration
feature provided on each face surface; and said mounting
mechanism including a registration feature provided on said
chipper body and cooperative with the registration features
of both face surfaces to selectively position the
corresponding cutting edge at a desired cutting edge
location.
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
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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 a face view of a chipper head including a
plurality of knife holders and associate chipper knives mounted
thereon in accordance with a preferred embodiment of the present
invention.
FIG. 2 is a front view of a knife holder of FIG. 1 further
detailing a clamping arrangement and a pair of knives clamped
thereby.
FIG. 3 is a sectional view of the holder, clamp, and a knife
of FIG. 2 as taken along lines 3-3 of FIG. 2.
FIG. 4 is a sectional view similar to that of FIG. 3 but taken
along lines 4-4 of FIG. 2.
FIG. 5 is a back view of the holder, clamp, and a keeper bar
as taken along lines 5-5 of FIG. 3.
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FIG. 6 is a perspective view of a pair of chipper knives held
in the knife holder of FIGS. 1-5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the invention as illustrated in
the drawings comprises generally a chipper knife and associated
support structure providing the desirable characteristics of
reduced maintenance and reduced expertise in the task of
dismounting and remounting chipper knives while maintaining
consistent a cutting plane defined by a plurality of such chipper
knives. Furthermore, the illustrated embodiment of the present
invention improves prior chipper knife and support structure
configurations by incorporating a portion of the chip breaker
system into the chipper knife. In this manner, the leading portion
of the chip breaker system, i.e., the wearing portion thereof, is
replaced when replacing or reversing chipper knives. In this
manner, the support structure for the chipper knife need not wear
away and need not require periodic replacement. Overall, the
chipper knife system of the present invention provides a dual edge,
reversible, reusable, and eventually disposable chipper knife of
small mass and small cost of manufacture.
FIG. 1 illustrates a chipper system 10 including a plurality
of knife holders 12 bolted to a chipper head 14 and carrying each
a pair of knives 16 and 20. As may be appreciated, chipper head 14
rotates at high speed and a wood article is presented to the knife
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system 10. FIG. 2 shows knife system 10 with holder 12 bolted to
the chipper head 14 in conventional manner. FIGS. 3-5 show various
views of the knife system 10.
With reference to FIGS. 1-6, knife holder 12 corresponds
generally to a "bent-knife" configuration, but provides by two
separate straight cutting edge knives, i.e., hogging knife 16 and
planing knife 20, the equivalent of a "bent-knife" arrangement.
Knives 16 and 20 are each "reversible" knives, each having two
cutting edges whereby extended use may be obtained from each of
knives 16 and 20 by reverse mounting thereof without an
intermediate surfacing step. Furthermore, and as will be explained
more fully hereafter, the mounting and clamping arrangement
provided for knives 16 and 20 allows pre-registration of knives 16
and 20. A relatively less skilled worker may thereby dismount
knives 16 and 20, reverse orientation thereof, and remount knives
16 and 20 to present a new cutting edge without detailed, precise,
and time consuming calibration of knives 16 and 20 positioning.
With particular reference to the view presented in FIG. 2,
holder 12 includes an angled plate portion 17 and a vertical plate
portion 19. A unitary clamp 18 corresponds in shape to that of
plate portions 17 and 19 of holder 12 whereby knives 16 and 20 are
captured between clamp 18 and holder 12 in a "bent-knife"
configuration as illustrated. More particularly, clamp 18 captures
knife 16 against the under-surface of plate portion 17 and captures
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knife 20 against the under-surface of plate portion 19. Holder 12
includes three counter bored apertures 12b through plate portion 17
and one counter bored aperture 12b through its plate portion 19.
Clamp 18 includes four corresponding threaded apertures 18c whereby
mounting bolts 11 passing through bores 12b and threadably engaging
apertures 18c draw clamp 18 toward holder 12 and capture knives 16
and 20 therebetween.
An upper leading and inclined surface 12a (FIGS. 3 and 4) of
holder 12 angles down toward knife 16. The cutting edges 16a of
knife 16 terminate corresponding inclined cutting surfaces 16b of
the knife 16. In accordance with the present invention, knife 16
includes ridge or nose structures 16c on each side integrally
formed with knife 16 and providing, as described more fully
hereafter, a leading and wearing component of a chip breaking
system of the knife system 10. Clamp 18 provides a leading and
inclined surface 18b (FIGS. 3 and 4) directed toward the knife 16.
Surface 18b, generally co-planar with the exposed surface of one of
nose structures 16c, completes the chip breaking surface for the
knife system 10.
Planing knife 20 includes components similarly labeled, i.e.,
edges 20a, inclined cutting surfaces 20b, and noses 20c on each
side. The noses 16c and 20c are beveled as indicated generally by
reference numeral 22 (FIG. 2) to accommodate the close joining of
knives 16 and 20 to form a single corner point for the combined
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knife edges 16a and 16b to establish a "bent-knife" configuration.
Because nose structures 16c and 20c comprise the leading and
wearable components of the chip breaking system, the surface 18b of
clamp 18 does not significantly wear, and clamp 18 need not be
periodically dismounted and replaced or repaired in order to
maintain consistent chip size and quality. When knives 16 and 20
are replaced or reoriented, new leading portions, i.e., noses 16c
and 20c, of the chip breaking system are provided. Accordingly,
the present invention provides a disposable chip breaking component
for the chipper knife system 10. Nose structures 16c and 20c
eliminate opportunity for sawdust and particles to wedge also
between the knives 16 and 20 and supporting clamp 18. Such wedging
of sawdust is significant problem and can actually result in
throwing a chipping knife during operation due to the loss of clamp
force.
The following discussion will focus on the relationship
between knife 16, clamp 18, and holder 12. It will be understood,
however, that the structure and mounting of knife 20 is similar to
that of knife 16. Knife 20 may be taken as virtually identical to
knife 16 except for the lateral dimension, i.e., parallel to
cutting edge 20a. Thus, as will be appreciated by those skilled in
the art, the following description of knife 16 and its relationship
to clamp 18 and holder 12 also supports a complete understanding of
the same relationship between knife 20, clamp 18, and holder 12.
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In FIG. 3, the holder 12 is shown including one of the counter
bores 12b in opposition to one of the threaded bore 18c of clamp
18. The knife 16 is shown in cross section including cutting edges
16a and inclined cutting surfaces 16b. Also shown integral to
knife 16 are the nose structures 16c having triangular cross-
section in the view of FIG. 3 and residing on opposing sides of
knife 16. The downward facing nose structure 16c, in the view of
FIG. 3, cooperates with the surface 18b of clamp 18 to define, as
noted above, a chip breaking surface indicated at reference numeral
30. The upward facing nose 16c resides within a relief 32 of
holder 12. More specifically, relief 32 is an elongate channel
provided in the downward facing surface 12c of holder 12.
Knife 16 further includes upper and lower registration slots
16d. Slots 16d run parallel to knife edge 16a. Each downward
facing slot 16d receives a corresponding upstanding dowels 34
integral to the clamp 18. At least two dowels 34 should be
provided for knife 16 maintain appropriate registration of the
knife 16 relative to clamp 18. As may be appreciated, knife 20
includes a registration slot 20d and receives corresponding dowels
for fixed positional relationship relative to clamp 18. In the
contemplated form of the present invention, a single dowel 34 can
be used in the slot 20d of knife 20. Knife 20 may be provided with
additional registration surfaces, i.e., its side edges bearing
against a portion of holder 12, whereby a single dowel 34 fixes the
position and orientation of edge 20a relative to clamp 18. Once
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knife 20 is secured in position, knife 16 is adjusted laterally,
i.e., moved parallel to its edge 16a, to establish a desired
relative position between knives 16 and 20. Dowels 34 should not
"bottom out" in the registration slots, e.g., dowel 34 height is
less than slot 16d depth. As may be appreciated, dowels 34 may be
integrated into clamp 18 by drilling and pressing dowels 34
therein. Accordingly, dowels 34 may be of different, i.e.,
stronger and less wearable, material relative to that of clamp 18.
The upward facing slot 16d is covered by the downward facing (in
the view of FIG. 3) surface 12c of holder 12.
Thus, knives 16 and 20 have fixed position relation, i. e. , are
registered, relative to clamp 18 by virtue of the registration
slots 16d and 20d, respectively. Positional adjustment for knives
16 and 20 is further accomplished, therefore, by adjusting the
position of clamp 18. Because clamp 18 is held in place by bolts
11 threaded into apertures 18c, bores 12b of holder 12 should be
slightly oversized to accommodate slight movement of clamp 18 in
calibrating the position of knives 16 and 20. Bores 12b may be
oversized, therefore, by 1/16 to 1/8 inch relative to the diameter
of bolts 11.
A keeper bar 40 lies intermediate of holder 12 and clamp 18 at
the rear portion, i.e., most distant from knife 16, of holder 12
and clamp 18. Keeper bar 40 includes an upstanding elongate key
40a received closely within a keyway 42 of holder 12. In other
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words, a close tolerance exists between key 40a and keyway 42
whereby keeper bar 40 maintains fixed position relative to holder
12. Keeper bar 40 includes a forward protruding ear 44 of height
corresponding generally to the height, i.e., thickness, of blade
16. In this manner, by capturing ear 44 and blade 16 between
holder 12 and clamp 18 and tightening mounting bolts 11 provided in
bores 12b and apertures 18c, knife 16 is well secured between the
holder 12 and clamp 18.
Keeper bar 40 provides an adjustment mechanism defining a
cutting plane 46 relative to holder 12. As may be appreciated,
keeper bar 40 also provides adjustment to define a cutting plane
for knife 20 relative to holder 12. More particularly, with the
keeper bar 40 maintained in fixed position relative to holder 12,
i.e., by virtue of key 40a and keyway 42, clamp 18 is adjustably
positioned relative to keeper bar 40, and thereby adjustably
positioned relative to holder 12. Additionally, a set of locking
bolts 70 couples holder 12 and keeper 40 to further fix the
position of keeper 40 relative to holder 12. By positioning ~of all
clamps 18, one positions of all knives 16 and 20. Adjusting screws
50 threadably engage keeper bar 40 and protrude therefrom to abut
a rear edge 52 of clamp 18. Each of adjusting screws 50 further
include a lock nut 54. In this manner, the position of clamp 18 is
precisely adjusted relative to keeper bar 40, and therefore
relative to holder 12.
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Once the adjustment screws 50 are suitably positioned, a set
of locking bolts 60 (FIG. 4) fix the position of clamp 18 relative
to keeper bar 40. More particularly, each of bolts 60 pass through
a bore 62 of keeper bar 40 and threadably engage a tapped bore 64
of clamp 18. In other words, the locking bolts 60 draw the clamp
18 back towards keeper bar 40 and against screws 50 to lock the
relative position between keeper bar 40 and clamp 18. Clamp 18 is
thereby positioned relative to the keeper bar 40 by use of
adjustment screws 50 and locked in position by drawing clamp 18
against the adjustment screws 50 by operation of locking bolts 60.
FIG. 5 further illustrates the adjustment screws 50, locking bolts
60, and locking bolts 70.
Thus, present invention provides in its preferred form nose
structures 16c and 2oc integral to the chipping knives 16 and 20
providing a leading, wearing component of the chip breaking
surface. When the knife is reversed, i.e., other cutting edge
selected, the system also has in addition to a new cutting edge a
new leading portion of the chip breaking surface. The noses 16c
and 20c do wear, but are easily replaced and maintained
consistently over time to provide consistent chip size and
thickness important in subsequent processing of chips.
As may be appreciated, a relatively less skilled worker can
release clamp 18, grab the knives 16 and 20, flip over knives 16
and 20, and tighten clamp 18 without recalibrating knives 16 and 20
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relative to cutting plane 46. Prior chipper knife configurations,
especially unitary "bent-knife" configurations, require elaborate
adjustment or calibration in establishing the cutting plane
relative to the holder whenever a knife is dismounted. Under the
present invention, however, a relatively small amount of downtime
and expertise are required for the maintenance of the knife system
10.
Knives 16 and 20 are of significantly less mass than
traditional unitary "bent-knife" configurations. Knives 16 and 20
are not only reversible, i.e., having cutting edges on both sides,
but also are flipped-over when presenting a new cutting edge. By
such configuration, the transverse edge-to-edge dimension of each
of knives 16 and 20 is minimized. More particularly, with respect
to knife 16, and also applicable to knife 20, the slots 16d and
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noses 16c share space along the dimension transverse to edges 16a.
Prior reversible chipper knives maintain the same knife side in an
upward facing direction, i.e., are not flipped-over when reversing
edges. Under the configuration of the present invention, however,
even with the incorporation of noses 16c and slots 16d, the overall
dimension between cutting edges is minimized. By reducing the
dimension of knives 16 and 20, overall mass is reduced with
corresponding less cost of manufacture. Also, less horse power is
required to rotate a set of such knives 16 and 20.
Furthermore, the configuration of knives 16 and 20 supports
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improved registration with respect to clamp 18. In particular,
each of the cutting edges 16a has its own corresponding
registration slot 16d and each of the cutting edges 20a has its own
corresponding registration slot 20d. By providing independent
registration structures for each cutting edge, a consistent
dimension is maintained between the cutting edge and associated
registration slot. Honing procedures applied to one cutting edge
do not affect registration of the other cutting edge. Thus, the
registration structure for each of the cutting edges is independent
relative to that of the other cutting edge on the same knife.
Overall, by providing independent registration structures relative
to the wearing and periodically honed cutting edges provides more
consistent overall chip size.
The knives 16 and 20 may also be considered "disposable"
knives, after having been honed several times. This satisfies an
industry need for reusable, disposable chipper knives and also
satisfies a need for little or no expertise or precise calibration
steps when reversing chipper knives. Once the knife system 10 of
the present invention is calibrated relative to the cutting plane
46, i.e., the clamp 18 is adjusted to establish desired position
for all knives 16 and 20 on cutter head 14, no further calibration
steps are required. Thus, following initial setup of knife system
10, substantially less downtime is taken to reverse chipper knives
16 and 20.
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By incorporating the nose structures 16c into the chip
breaking surface of the knife system, the relatively more permanent
clamp 18 need not be a wear structure in the knife system, but
rather is protected by virtue of the nose structures 16c and 20c.
Accordingly, by use of the knife system 10 of the present invention
the supporting holder and clamp system have extended life, thereby
contributing to increased value in the investment in such
equipment.
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.
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