Note: Descriptions are shown in the official language in which they were submitted.
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CANADA
Applicant: Machinery Development Company Pty. Ltd.
Title: WORKHEAD WITH JAW ASSEMBLY FOR TI1VIBER
PROCESSING
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FIELD OF THE INVENTION
The present invention relates generally to an apparatus for timber processing
and
more particularly, to a timber processing workhead suitable for use in various
processing
operations such as the harvesting, debarking and carriage of trees.
BACKGROUND OF THE INVENTION
There are currently a number of known workheads used in forestry which are
each
specifically designed for one or more particular functions involved in timber
processing.
For example, there are certain workheads which are adapted for use in the
felling of trees,
others for removing the bark or for removing the limbs from felled trees,
others for the
"bucking" or cutting of felled trees to length, and yet others for the loading
or carriage of
processed logs into storage regions or onto transport vehicles. It is also
often necessary to
design such workheads so that they are specifically capable of use with either
hardwood or
softwood, or particular tree species.
An example of a prior art timber processing device specifically adapted for
tree
felling is provided by International Application No. PCT/SE93/00601, published
on January
12, 1995 in the name of Widegren. The device according to Widegren includes a
pair of
shearing elements together with a sawing device, so as to effect tree felling
either by sawing
or shearing. Another dedicated cutting and sawing unit is exemplified by
International
Application No. PCT/SE91/00606, published on April 2, 1992 in the name of
Jansson. The
unit according to Jansson includes a saw rotatably mounted on a motor stand
and knives
which project from a hub part of the saw. The knives co-act with a toothed
device on the
motor stand, such as to obtain a cutting action in addition to a sawing
action.
Devices intended for dedicated tree delimbing are exemplified by the teachings
of
Australian Patent Application No. 76409/91, published on November 14, 1991 and
identifying Wingate-Hill et al. as inventors, Australian Patent Application
No. 29636/92
published on November 26, 1992 in the name of Milbourn, and Australian Patent
No.
618,679 granted January 2, 1992 in the name of Milbourn. The Wingate-Hill et
al. device
comprises a milling head having helical cutters, the milling head being
mounted on support
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means such that the axis of rotation of the head is substantially parallel to
the longitudinal
axis of the trunk or log being delimbed. The first Milbourn device mentioned
above
consists of a workhead housing having a circular cutter wheel mounted thereon
to rotate
about a vertical axis. A chain saw is mounted by a swivel device on the
housing and above
the wheel. The second-mentioned Milbourn device consists of a workhead mounted
on an
articulated boom that can move vertically along a tree to trim the branches
thereof.
Some known timber processing workheads provide a debarking roller assembly
which engages the trunk of a felled tree and is configured so that when the
rollers are
activated, the trunk is drawn between the roller assembly. By their
compressive action
against the trunk, the rollers of the assembly cause the tree bark to loosen
or separate from
the truck, thereby at least partially debarking the trunk of the tree. This
technique of timber
debarking is known to those skilled in the art as compression debarking.
Because of the
nature or construction of compression debarking rollers currently in use, the
debarking
capability of some such rollers is limited. This deficiency may require
supplementing the
debarking action of the rollers, for instance by providing fixed or rotating
knife edges to cut
through bark which becomes loosened from the tree trunk, but which is not
entirely
removed by the rollers, or by arranging as many as six compression debarking
rollers in an
apparatus to ensure adequate circumferential coverage of a tree trunk drawn
therebetween.
An example of a prior art debarking apparatus is found in U.S. Patent No.
4,875,51 l,
issued on October 24, 1989 in the names of Wingate-Hill et al. This patent
teaches the use
of a plurality of pairs of concave rollers which are mounted in a spaced apart
configuration
along the linear passage of the log through the apparatus. The rollers in each
pair have
respective axes of rotation substantially parallel to each other. One pair of
rollers is
grooved or otherwise roughened or provided with welded-on bars, spikes or the
like for
gripping the surface of the timber being debarked, and for compressing the
timber and bark
such that the bark remains as a tube of enlarged section around the body of
the tree. A
second pair of rollers, including one or more knife blades, is provided
downstream of the
first pair of rollers, the second pair of rollers being arranged with their
axes of rotation
substantially perpendicular to the first pair of rollers. In another
embodiment according to
Wingate-Hill et al., a total of six rollers arranged in three pairs is
provided, each pair having
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parallel axes of rotation substantially at 60° relative to the
respective axes of the rollers in
each other pair. The Wingate-Hill et al. patent teaches that unless separate
bark cutting
means are provided, each of the six rollers will have respective blades
attached to or formed
on their outer surfaces. Another example of a debarking apparatus providing
compression
rollers, with circumferential knives on their outer surfaces to cut through
loosened bark, is
found in U. S. Patent No. 5,111,860 issued on May 12, 1992 and also in the
names of
Wingate-Hill et al.
Some prior art devices do combine several tree processing operations, such as
felling and bucking, delimbing and bucking, or felling, delimbing and bucking.
Examples
of prior art devices intended for various combined operations of tree felling,
bucking or
delimbing are found in United States Patent No. 3,981,336 issued on September
21, 1976 in
the name of Levesque, Soviet Patent No. 946,458 issued on July 30, 1982 in the
names of
Samodov et al., and International Application No. PCT/SE88/00338 published on
December 29, 1988, and identifying Westlund as the inventor thereof. The
Levesque device
comprises a harvester head having a cutting mechanism consisting of a pair of
shear-like
cutting edges and delimbing knives mounted to a support member. The head can
be
positioned vertically by a boom against a tree to be severed and then rotated
into a
horizontal position for the delimbing and further severing of the tree into
bolts. The Soviet
device mentioned above consists of a jib mounted onto a turnable, the jib
providing drive
rollers for translating a tree trunk through branch stripping blades. A saw
attachment for
felling trees may also be provided at the terminal end of the jib. As for the
Westlund
device, it consists of a delimbing tool having knives and a gripper which are
moveable
relative to one another in the axial direction of a trunk located in the
gripper, such as to
delimb the trunk as it is translated. A pivotable saw attachment is provided
for felling and
bucking of timber. None of these combined processing devices provides
integrated means
for debarking the processed timber.
An example of a prior art device which is intended for the combined functions
tree
felling and bucking is found in International Application No. PCT/SE90/00042
published
on July 26, 1990 and identifying Keller as the inventor thereof. The harvester
according to
Keller provides for two pairs of grapple arms, a feeding device in the form of
a driving belt
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or driving wheel, and a cutting device having a pivotable guide bar around
which a saw
chain is rotatable at high speed. The grapple arms of Keller serve to seize
the tree trunk and
to delimb the trunk as it is longitudinally fed through the harvester by the
feeding device.
The Keller device does not provide for a debarking function.
Other devices providing for various combined tree processing functions are
found in
U. S. Patent Nos. 4,194,542 and 5,219,010 issued respectively on March 25,
1980 and June
15, 1993, each in the name ofEriksson, U.S. Patent No. 4,766,939 issued on
August 30,
1988 in the name of Forslund, and International Applications Nos.
PCT/FI92/00027 and
PCT/FI92/00227 published respectively on September 3, 1992 and March 4, 1993,
each in
the name of Moisio. The Eriksson patents disclose tree processing devices
which include
cooperating grabbing arms or delimbing members, drive rollers to feed the tree
through the
devices and a pivotable severing device to cut the tree. The first-mentioned
Eriksson patent
provides a device wherein the drive rollers are arranged on the grabbing arms
in order to
follow the grabbing arms towards and away from a tree. The Forslund device
comprises
cooperating jaw arms, feeding units for the trunk and delimbing tools moveable
with the
feeding units in a common plane. The Moisio devices have cooperating grapple
arms, drive
rollers for the trunk and articulating delimbing cutters. None of the
foregoing devices
provides for the capability to debark a tree being processed.
Yet other devices providing for various combined tree processing functions are
found in International Application No. PCT/FI90/00147 published on December
13, 1990 in
the name of Ketonen, and Australian Patent No. 534,473 issued on February 2,
1984 in the
names of Barnett et al. The Ketonen apparatus consists of a frame, two feed
tracks disposed
opposite one another for translating a tree, front and rear stripping blades
for delimbing, and
a pivotable saw for cutting bolts to length. The Australian patent to Barnett
et al. discloses
a head member for tree processing which includes delimbing means, a clasping
arrangement
of arm members and a pair of shear knives for felling of a tree. As the head
member
according to Barnett et al. is caused to gravitate down a tree to its base,
the momentum of
the head member during the downward movement is such as to cause delimbing of
the tree.
The same patent also teaches that the clasping arrangement of the arm members
provides
for removal of at least some of the bark from the tree during its delimbing.
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Many workheads of these known types are typically adapted for use with
machines
having a boom or beam to which the workhead is securable. Generally, workheads
which
are used in tree felling and processing operations are secured to a boom
through an
uncoupled grapple or swinging link, known in the art as a dangle connection.
For instance,
Canadian Patent No. 1,083,016, issued on August 5, 1980 in the name of Hagan,
teaches a
delimbing and loading head which is articulated on the end of an arm by means
of a
universal joint. The joint is connected to the head at approximately its
center of gravity so
that it can swivel freely on two axes and automatically remain in a
substantially horizontal
position throughout delimbing and loading operations. Such prior art links
provide for
limited control of the processing head during a felling operation. Other prior
art links,
while providing for enhanced control of the workhead, may not achieve an
appropriate
range of motion for the workhead in all required directions of movement. Yet
other prior
art connections do not provide for ready maintenance access to electrical or
hydraulic
control lines, or may not be configured in a compact design.
It is therefore an object of the present invention to provide a timber
processing
workhead which is intended to alleviate or overcome one or more of the
aforementioned
disadvantages or problems associated with known timber processing workheads.
It is another object of the present invention to provide a versatile
processing
workhead which may serve in a plurality of timber processing functions, such
as felling,
delimbing, debarking, bucking, carriage and loading of trees.
It is a further object in another aspect of the present invention to provide a
feed
roller for use in a feed roller assembly of a timber processing workhead,
which feed roller is
also suited for compression debarking of felled timber.
It is a further object in another aspect of the present invention to provide a
rotatable
and pivotable coupled wrist connection between a processing workhead and a
beam or
boom to which it is connected, which is intended to provide an appropriate
range of motion
and a sufficient degree of control for the workhead operator involved in
various timber
processing activities.
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It is a yet further object of the present invention to provide the rotatable
and
pivotable coupled wrist connection of the kind mentioned above, wherein the
connection is
associated with a fluid delivery manifold that is configured in a relatively
compact design,
and which is intended to provide for a sufficient degree of access to
electrical and hydraulic
control lines for maintenance purposes.
BRIEF DESCRIPTION OF THE INVENTION
According to one broad aspect of the present invention, there is provided a
workhead for timber processing, the workhead comprising:
(a) a main body;
(b) mounting means for attachment of the main body to a support structure;
(c) wrist means for pivotal movement of the main body relative to the support
structure about a pivot axis and for dewing movement of the main body relative
to the
support structure about a slew axis;
(d) hydraulically powered timber processing means provided with the main body;
(e) fluid delivery means for supplying hydraulic fluid to the powered timber
processing means, the fluid delivery means comprising a swivel hydraulic
manifold
extending externally of the main body along the slew axis and a fixed
hydraulic manifold
attached to the main body, the swivel manifold comprising a substantially
cylindrical rotor
portion and a corresponding sleeve portion in sealed rotational engagement
therewith, the
rotor portion being attached to the fixed manifold, the sleeve portion
providing a fluid inlet
port and the rotor portion providing a corresponding fluid receiving channel
disposed
circumferentially along an outer surface thereof, the fluid receiving channel
being in
constant fluid communication with the fluid inlet port of the sleeve portion
throughout
relative rotational movement of the rotor portion and the sleeve portion, the
fluid receiving
channel being in fluid communication with a corresponding fluid through
passage provided
in the fixed manifold, the fixed manifold providing an outlet port on an
external surface
thereof in fluid communication with the fluid through passage thereof; and
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wherein the outlet port of the fixed manifold supplies hydraulic fluid
received from
the inlet port of the swivel manifold to the powered timber processing means
of the main
body of the workhead.
According to another broad aspect of the present invention, there is provided
a feed
roller for use in timber processing for compressive removal of bark from a
felled tree, the
feed roller comprising:
(a) a base portion providing a cylindrical outer surface and opposed terminal
ends, the base portion being rotatable about a longitudinal axis thereof; and
(b) a plurality of engaging means for engaging the surface of timber, the
engaging means projecting generally radially from the base portion and
extending along the
outer surface thereof between the opposed terminal ends of the base portion in
a generally
helical configuration, each engaging means being spaced apart from an adjacent
engaging
means in a substantially parallel relationship with respect thereto, each
engaging means
having a contacting edge to engage the surface of timber, the contacting edge
providing
blunt longitudinally extending projections thereon.
According to yet another broad aspect of the present invention, there is
provided a
workhead for timber processing, the workhead comprising:
(a) a main body;
(b) a jaw assembly for grappling timber, the jaw assembly including first and
second cooperating pairs of jaw arms, the jaw arms each having a free end and
a connected
end, the connected ends of the jaw arms each being pivotally mounted to the
main body for
relative movement of the jaw arms of each cooperating pair between an
operative position,
wherein the free ends of the jaw arms thereof are brought towards each other
to grapple
timber therebetween, and a release position, wherein the free ends of the jaw
arms thereof
are spaced apart from each other to surrender said timber, a jaw arm in each
cooperating
pair of jaw arms being mounted adjacent a jaw arm of the other cooperating
pair along the
same side of the main body of the workhead;
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(c) a timber delimbing means associated with the first cooperating pair of jaw
arms, the timber delimbing means comprising cutting blades provided
respectively on each
of the jaw arms thereof; and
(d) a feed roller assembly having: a plurality of feed rollers driven in
cooperative
rotation for translating a felled tree along a longitudinal axis thereof
through the delimbing
means when the jaw arms thereof are actuated to the operative position to
encircle the felled
tree about its circumference, the cutting blades being positioned on the jaw
arms of the
delimbing means to effect delimbing of the felled tree as it is axially
translated
therethrough; first and second feed rollers of the feed roller assembly each
being associated
with the respective jaw arms of the second cooperating pair of jaw arms of the
jaw
assembly, the first and second feed rollers each engaging the felled tree when
the jaw arms
associated therewith are actuated to the operative position, the feed rollers
each having a
respective axis of rotation substantially parallel to respective planes of
pivotal motion
corresponding to the jaw arms associated therewith; and a third feed roller of
the feed roller
assembly being rotatably mounted on the main body, for pivotal movement
relative thereto,
between an operative position wherein the third feed roller engages a tree
trunk being
grappled by the jaw assembly and a retracted position wherein the third feed
roller
disengages the tree trunk.
With reference to preferred embodiments of the present invention, there is
provided
a workhead suitable for use with an apparatus having a beam or boom
operatively
connected to a support or carriage, the workhead comprising a main body,
mounting means
operatively connected to the main body for attaching the workhead to the beam
or boom,
coupling means for permitting pivotal movement of the workhead about a pivot
axis relative
to the boom, stewing means for permitting rotation of the main body about a
slew axis, the
pivotal movement about the pivot axis and the rotational movement about the
slew axis
permitting at least limited universal movement of the main body relative to
the beam or
boom when the workhead is operatively connected thereto, and a jaw assembly
comprising
at least two cooperating jaw arms which are each pivotally mounted to the main
body for
movement between an operative position and a release position.
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When in use in the operative position, the jaw arms are adapted to hold or
engage
one or more tree trunks therebetween, and in the release position, the jaw
arms are spaced
apart relative to one another to release any tree trunks held when the jaw
arms are
previously in the operative position.
According to one particular embodiment of the present invention, the workhead
is
adapted to perform a series of varied processing operations. According to
another particular
embodiment of the invention, the workhead is adapted for a lifting and
carrying function.
For example, in the first mentioned embodiment, the processing head may be
able to
perform two or more of the following operations: it may be adapted to grip the
tree during
the felling operation and be capable of lowering it to the ground; it may be
adapted to
remove the bark from the felled tree; it may be adapted to remove limbs from
the felled tree;
it may be adapted to cut to a selected length the trunk of the tree; and/or it
may be adapted
to load, deposit or carry the processed logs in or to a desired position,
known to some
skilled in this art as "hoe-chucking" or "shovel logging".
The main body of the workhead according to either of the aforementioned
embodiments may be in the form of a support structure or frame to or by which
the
mounting means, coupling means, stewing means and a jaw assembly all may be
operatively supported. The mounting means may be in the form of a bracket
which is
operatively connected by coupling means to the beam or boom of the support
structure or
carriage for the workhead.
The coupling means for operatively connecting the mounting bracket of the
workhead to the beam or boom of the support structure or carriage includes an
actuating
means which is preferably in the form of a hydraulic actuator mechanism. One
end of the
actuator mechanism is connected to the boom and the other end is connected to
a guide
linkage mechanism for interconnecting of the boom and the bracket. The
reciprocating
motion of the actuator mechanism acting through the guide linkage mechanism
will cause
pivotal movement of the mounting bracket and thereby the main body of the
workhead.
Preferably, two guide links are provided, one being connected between the boom
and the
hydraulic actuator and the other being connected between the actuator and the
bracket.
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Preferably, the dewing means for the workhead comprises a slew bearing adapted
to
be disposed between the mounting bracket and the main body of the workhead.
Drive
means associated with the slew bearing are provided for causing rotation of
the main body
about the slew axis. Such drive means may be in the form of hydraulic motors,
although it
will be appreciated that other forms of drive means could be utilised for the
slew bearing.
In the embodiment discussed above for which the workhead is particularly
adapted
as a lifting and carrying mechanism, the jaw assembly may comprise two sets of
spaced
apart cooperating jaw arms, each of the arms having one end pivotally
connected to the
main body so that the cooperating arms in each set can pivot towards or away
from each
other between respective operative and release positions. The jaw assembly may
further
include cross-members extending between respective adjacently disposed arms in
each set.
In the embodiment referred to above for which the workhead is adapted to
perform
varied functions, the jaw assembly may comprise two sets of jaw members. One
set of jaw
members consists of a pair of cooperating jaw arms pivotally connected to the
main body
and having associated therewith a plurality of feed rollers which form part of
a feed roller
assembly. The feed rollers are each adapted and are preferably together
configured to rotate
and draw the tree trunk therebetween when the feed rollers are rotated. A
second set of
cooperating j aw arms may be provided, the second set being arranged in a
spaced apart
relationship to the first set. The arms of the second set have delimbing means
thereon, for
instance blade sections with knife edges, so that in their operative position
and when the
tree is translated through the jaws by the feed roller assembly, the blade
sections with knife
edges are positioned to remove limbs from the tree trunk. A delimbing knife
may also be
provided in the main body of the workhead to provide for greater
circumferential coverage
of a trunk during its delimbing by the second set of arms of the workhead.
The feed roller assembly may further include one or more additional rollers
located
in the main body of the workhead, which are adapted to cooperate with the feed
rollers in
the jaw arms to define the feed roller assembly. There is at least a single
feed roller
mounted in the body of the head. Preferably, this feed roller is a retractable
cushion roller
mounted on a swinging arm which may, for example, be controlled by a hydraulic
actuator.
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When the workhead is in its processing mode, the hydraulic actuator is
activated and the
cushion roller is pushed forward to engage the log. During all other modes of
operation, the
hydraulic actuator is not activated and the cushion roller remains in a
retracted position.
The purpose of retracting this feed roller is that during felling, the tree
will be in contact
only with the feed rollers on the arms and with portions of the main body of
the head, such
as the delimbing knife provided thereon. This ensures maximum clamping
stability during
felling as well as when handling processed logs, such as when timber is being
carried or
loaded onto a transport vehicle. Additionally, a relief valve may be provided
in the
hydraulic supply line for the hydraulic actuator which activates the swinging
arm of the
cushion roller. The relief valve may be set to a preselected pressure so as to
reduce the
supply of hydraulic fluid to the swinging arm actuator in the event of
excessive radial load
to the roller, for instance, as may occur during the processing of crooked
trees.
The processing head may further include a severing means such as a saw
attachment
which may be pivotally mounted to the main body. In operation, the saw
attachment can be
pivoted in order to cut across the trunk of a tree or log, for felling or
bucking purposes.
Other severing means may be adapted for use with the workhead according to the
present
invention, as will be apparent to those skilled in this art.
A measuring device may be provided with the processing workhead to measure the
length of logs to be cut. The measuring device may be mounted on a mechanism
forming
part of the main body which allows the measuring device to be held in a
protruding position
whilst in a processing mode. During all other modes of operation, the
measuring device is
in a retracted position to avoid damage. Preferably, the measuring device is
resiliently
mounted on the main body to accommodate dimensional variances and surface
discontinuities encountered along the length of processed logs. Those skilled
in this art will
appreciate that other measuring devices may be incorporated for use with the
workhead
according to the present invention.
The particular design of the feed rollers for the workhead described above
forms
another aspect of the present invention. The design of the feed roller may
permit it to be
used in the debarking of a wide variety of tree species.
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With reference to embodiments pertaining to this aspect of the present
invention,
there is provided a feed roller for use in a feed roller assembly of a
processing workhead,
the feed roller comprising a base section having a generally cylindrical outer
surface, and a
plurality of engaging bars which are secured to or formed integral with the
outer surface to
project generally radially therefrom. The engaging bars are spaced apart and
generally
parallel to one another, each engaging bar extending in a generally spiral
configuration from
one end of the feed roller base section to the other.
Preferably, each of the engaging bars is of greater height dimension towards
the end
portions of the base section of the feed roller, and is arranged to taper
inwardly as the bar
approaches an intermediate portion thereof. The outer edges of each of the
bars, taken
along a parallel plane running between the end portions of the base, trace a
generally
concave or fluted engaging edge. Furthermore, it is desirable that the top
surface of the
engaging bars, when viewed in longitudinal cross-section, be generally concave
in shape so
as to provide a generally concave envelope surface to the feed rollers.
Preferably, the feed rollers of the processing head are driven by a load
sensing
pressure compensated hydraulic system which is fitted with a flow dividing
valve to give
positive drive to all rollers under all conditions. As well, hydraulic fluid
is supplied and
returned through the workhead wrist connection via a combined swivel manifold
and block
manifold, which results in a compact design.
The processing workhead according to the present invention is capable of
cutting a
tree off its base, holding the felled tree in an upright position, moving the
tree while in this
position to various other desired positions, and lowering or raising the tree
in numerous
desired directions. Such manipulation of a felled tree may be made prior to,
during or after
delimbing, debarking and bucking of the tree by the processing workhead. In
addition, the
processing workhead is also advantageously capable of grappling, bunching,
shovel-logging
and loading a plurality of processed logs.
BRIEF DESCRIPTION OF THE DRAWINGS
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For purposes of illustration and understanding of the invention, but not of
limitation,
reference will be made to the following drawings in describing various aspects
and
embodiments of the present invention, in which:
Figure 1 is a schematic perspective view of a timber processing workhead
according
to a first embodiment of the present invention;
Figure 2 is a side elevation of the workhead according to the present
invention,
being operatively connected to the articulated boom of an associated all-
terrain vehicle;
Figure 3 is a detail of the coupling mechanism by which the workhead is
coupled to
the vehicle boom of Figure 2, showing a hydraulic actuator of the boom in a
fully extended
stroke position;
Figure 4 is a similar view to Figure 3, with the hydraulic actuator of the
coupling
mechanism being shown in a fully retracted stroke position;
Figure 5 is an end elevation of the timber processing workhead according to
the
embodiment of the present invention shown in Figure 1;
Figure 6 is an underside plan view of the workhead of Figure 1;
Figure 7 is a side elevation of the workhead of Figure 1;
Figure 8 is a side elevation of a feed roller according to another aspect of
the present
invention;
Figure 9 is an end elevation of the roller shown in Figure 8;
Figure 10 is a side elevation of a portion of an engaging bar which forms part
of the
feed roller according to the present invention;
Figure 11 is an end elevation of the working bar portion of Figure 10, viewed
along
direction "A" of Figure 10;
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Figure 12 is a partial cross-sectional view of the fluted outside edge of the
working
bar of Figure 10;
Figure 13 is a schematic side elevation of two engaging bar portions of Figure
11,
showing their helical placement along the outer surface of a feed roller
according to the
present invention;
Figure 14 is a schematic cut-away section of a feed roller and housing
according to
another aspect of the present invention;
Figure 15 is a partial cross-sectional end view of a retractable cushion
roller
assembly located in the main body of the workhead according to Figure 1;
Figure 16 is a partial cross-sectional side view of the cushion roller
assembly of
Figure 15;
Figure 17 is a partial cross-sectional view of the main body of the workhead
of
Figure 1, showing a retractable length measuring device for use with the
present invention;
Figure 18 is a schematic end elevation of the workhead according to a second
embodiment of the present invention;
Figure 19 is a schematic underside plan view of the workhead shown in Figure
18;
Figure 20 is a schematic side elevation of the workhead of Figure 18;
Figure 21 is a schematic layout of a hydraulic circuit adapted for operating
and
controlling the various powered devices of the workhead according to Figure 1;
Figure 22 is an exploded cross-sectional view of a dewing means according to
yet
another aspect of the present invention, the stewing means being suited for
use with the
workhead of the present invention;
Figure 23 is a top plan view of the stewing means of Figure 22; and
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Figure 24 is a detailed partial cross-sectional view of drive means for the
dewing
means of Figures 22 and 23;
Figure 25 is a schematic cross-sectional view of a swivel manifold and
underlying
block manifold provided in the main body of the workhead of the present
invention; and
Figure 26 is a schematic perspective view of the manifolds of Figure 25,
showing
the relative dewing movement thereof.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
With particular reference to Figure 1 and Figures 5 to 7, the timber
processing
workhead 10 according to a first embodiment of the present invention includes
a main body
11 and a wrist connection 5 which permits at least limited universal movement
of the main
body of the workhead relative to a boom 71 or other support member thereof.
This
particular embodiment of the invention is intended to be suitable for carrying
out a variety
of timber processing operations, including controlled felling, delimbing,
debarking,
bucking, carriage, and transporting from one site to another. The main body 11
of the
workhead 10 is preferably in the form of a support structure or frame to or by
which the
wrist connection 5, a jaw assembly 30 consisting of two pairs of cooperating
jaw arms 21
and 31, and timber feed means in the form of driven feed rollers 36 to 39 are
operatively
supported. Details of the specific features of workheads according to various
embodiments
of the present invention are explained more clearly herebelow with reference
to Figures S to
7 and Figures 18 to 20.
Referring now to Figures 2 to 4, the timber processing workhead 10 according
to the
present invention is shown connected to an articulated boomset 71 of an
associated all-
terrain vehicle 70 of the kind well known to those skilled in this art. As
shown in Figure 2,
the boomset 71 is pivotally supported by the vehicle 70, the boomset having an
inner
section 72 and an outer section 73, the inner and outer sections being capable
of pivotal
movement relative to one another about a pivot connection as at 76. The
vehicle further
includes an operator cabin 74, an endless track drive system 75 and a stewing
ring 77, also
well known to those skilled in this art.
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The wrist connection 5 of the workhead comprises a mounting bracket 12 to
which
is connected a coupling means 13 for pivotal motion of the workhead, as
explained below.
The workhead is pivotally connected, as at 12a, by means of the mounting
bracket 12 at the
terminal end of outer section 73 of boomset 71. Coupling means 13 for the
workhead
comprises an actuator means, which is preferably a hydraulic actuator
mechanism 14 well
known to those skilled in this art. The actuator 14 is pivotally mounted at
its cylinder end to
outer section 73 of boomset 71, as at 14c. The coupling means further includes
a pair of
guide links 15 and 16, each of which have an end thereof pivotally connected,
as at 14b, to
the terminal end of ram 14a of the actuator 14. The end of guide link 15
opposite the
actuator ram 14a is pivotally connected to the terminal end of outer section
73 of boom 71
adjacent the mounting bracket 12, as at 73a. The end of guide link 16 opposite
the actuator
ram 14a is pivotally connected to the mounting bracket 12, as at 12b.
The coupling means 13 operatively connect the workhead to the boom 71 so that
it
can pivot about an axis extending through pivot connection 12a, denoted as AA'
in Figure
5. The configuration of the coupling means 13 with the hydraulic actuator 14
placed
beneath the outer section 73 of boom 71, rather than above, advantageously
results in the
actuator being in a state of compression during many timber handling
manoeuvres in which
gravity will contribute to additional dynamic loading of the actuator
mechanism, such as in
timber handling operations.
The wrist connection S of workhead 10 also includes a dewing means, preferably
in
the form of a slew bearing 80 which is disposed between the main body 11 and
the
mounting bracket 12. Drive means associated with the slew bearing, preferably
in the form
of twin reversible hydraulic motors 108, cause rotation of main body 11 about
a slew axis,
denoted as BB' in Figure 4. Together, the operation of the coupling means 13
and slew
bearing 80 provide for an appropriate degree of universal movement of the main
body
relative to boom 71, as previously mentioned. Details concerning the features
and operation
of slew bearing 80 are provided herebelow.
Turning more specifically to Figures 5 to 7, the jaw assembly 30 of the
workhead 10
comprises two sets of jaw members or arms 21 and 31. As will be best noted in
Figures 6
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and 7, the jaw arms of each set are slightly off set with respect to one
another. The first set
of jaw arms 31 comprises two cooperating arms 32, 33 which again are arcuate
in shape and
are mounted for pivotal movement relative to the main body 11 of the workhead.
Each arm
32, 33 has a feed roller 36, 37 attached thereto, these rollers forming part
of a feed roller
assembly. The feed roller assembly further includes a pair of rollers 38 and
39 which are
disposed in the main body of the workhead. All of the feed rollers are
configured so that
when activated, they will translate and cause rotation of the tree trunk as it
passes between
the rollers. The feed rollers are described in greater detail herebelow, and
effect
compression debarking of a tree truck processed by the workhead 10.
The second set of jaw arms 21, which are disposed upstream with respect to the
direction of travel of a tree trunk through the jaw assembly during delimbing,
comprises
two cooperating arms 23 and 24, which are also generally arcuate in shape and
mounted for
pivotal movement towards or away from one another. Each of these arms has a
blade
section with knife edges 25, 26 associated therewith, which can trim limbs
from the tree
trunk as it is translated through the jaw members 21 by the feed roller
assembly. The arms
23, 24 provide flat surfaces 19 (Figure 6) thereon which trail the knife edges
of the blade
sections. However, those skilled in this art will appreciate that the surfaces
19 may be
sloped outwardly away from the knife edges, if desired, so as to prevent any
accumulation
of wood chips, branches or other cut material produced by the delimbing action
of the arms.
Each set of jaw arms 21 and 31 may be independently activated into a closed
operative position, wherein the free ends of the arms are brought towards each
other, or into
an open release position, wherein the arm ends are brought away from one
another. Each
set of jaw arms 21 and 31 is activated by a separate actuating means,
preferably in the form
of a hydraulic actuator 148 (shown schematically in Figure 18) well known to
those skilled
in this art.
A knife 27 is mounted on the main body 11 of the workhead to provide a more
complete circumferential coverage during delimbing together with the action of
blade
sections 25, 26. Those skilled in this art will appreciate that the knife 27
may be provided
as a fixed knife or as a retractable and outwardly biased floating knife, as
is well known.
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Area 20 of the main body (Figure 5), which trails the cutting edge of knife
27, may be
provided with a sloped deflecting surface (not shown) to prevent accumulation
of cut
material produced by the delimbing action of the knife. As well, a severing
means in the
form of a pivotally mounted hydraulic saw 6 is provided at one end of the main
body for
cutting processed logs to length and for tree felling.
Referring next to Figures 8 to 14, the feed roller 50 for use as a roller 36
to 39 of the
workhead comprises a base section 57 having a cylindrical outer surface 51 and
a plurality
of engaging means in the form of engaging vanes or bars 52 attached to or
formed integral
with the outer surface of the base section to project generally radially
therearound. The
engaging bars are adapted to extend from one end surface 58 of the roller to
the other in a
generally spiral or helical configuration, such that each engaging bar extends
180° around
the circumference of outer surface 51, as best shown in Figure 13. Each
engaging bar 52 is
preferably disposed on the outer surface 51 to form a helix angle of
approximately 40° with
respect to the longitudinal axis of the roller S0. Eight such engaging bars
are preferably
provided in an evenly spaced circumferential arrangement on each roller 50.
The engaging bars 52 may be formed from two bar portions 52a, placed end-to-
end
on the surface 51 of roller S0. Each bar portion 52a is generally arcuate in
shape, and may
be formed from a plate section provided with two thin slots 58, 59 through its
cross-section.
The slots are located adjacent the base edge 60 of the bar portion which is
intended to attach
to the outer surface 51 of roller 50. The slots 58, 59 may be formed in a
plate section for
bar portion 52a by means such as flame cutting, or other means known to those
skilled in
this art.
The provision of slots 58, 59 results in the bar portion 52a being divided
into three
sections, namely an inner section 61 a, an intermediate section 61 b and an
outer section 61 c,
each being angularly disposed with respect to the other. The outer section 61c
is located
adjacent an end face 58 of the roller S0, when the bar portion 52a is attached
to its outer
surface 51. Intermediate section 61b is located between the thin slots 58, 59.
The inner
section 61a of the bar portion 52a is located between the end faces 58 of a
roller 50 when
bar portion 52a is attached to outer surface 51 thereof. As best shown in
Figure 11, inner
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section 61 a extends from the bar portion at an angle a of approximately 15
° with respect to
intermediate section 61b. Likewise, outer section 61c ofbar portion 52a
extends angularly
from the bar portion at an angle a' of approximately 15° with respect
to the height
dimension of intermediate section 61 b of the bar. The angular relationship
between each of
the sections 61 a, 61b and 61 c of bar portion 52a may be obtained by bending
of the sections
once slots 58, 59 have been formed in the plate section for bar portion 52a.
Other means of
constructing or forming the bar portions will be apparent to those skilled in
this art.
As best shown in Figure 10, bar portion 52a has a greater height dimension
towards
the end portion 61 a, and is shaped to taper longitudinally to a lesser height
dimension
towards inner section 61 a. When two bar portions 52a are placed end-to-end on
the surface
51 of roller 50, this height tapering results in a generally concave envelope
surface for the
feed rollers 50 when viewed in longitudinal cross-section. The base edge 60 of
bar portion
52a is fixedly attached to the outer surface 51 of roller 50 preferably by
welded attachment.
Other means for constructing the roller 50 and its engaging bars 52 will be
apparent to those
skilled in this art.
The outer or contacting edge 54 of the bar portion 52a is intended to engage a
tree
trunk and cause rotation thereof as it passes through the feed roller assembly
of workhead
10. As best seen in Figure 12, outer edge 54, when viewed along a plane
parallel to the end
portions 58 of base 57 of the roller S0, traces a fluted or concave engaging
edge 62 to form
projecting and spaced apart lands 62a. The shape of the concave engaging edge
62 and the
provision of flat engaging surfaces at the outer edge 54 of bar portion 52a
produces an
engaging bar 52 for the feed roller which is intended to achieve only partial
penetration of
the bark of a felled tree while avoiding appreciable penetration of the
engaging bar into the
wood fibre portion thereof. In this manner, radial shearing of the bark is
lessened and the
compressive action of the engaging bar 52 required for compression debarking
is enhanced.
As well, damage to the wood fibre of a log is thereby averted or minimized.
Thus, the outer
edge 54 of an engaging bar 52 presents blunt longitudinally extending
projections thereon,
such as the lands 62a which constitute means for applying compressive force to
the bark of
the felled tree without substantially effecting the radial shearing thereof.
Preferably, the
blunt projections are disposed along substantially the entire length of each
engaging bar 52.
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Other blunt profiles of the outer edge of the engaging bars for achieving the
foregoing
purpose will be apparent to those skilled in this art.
With reference to Figure 14, each feed roller 50 is rotatably mounted in a
roller
housing 63. Base section 57 of the roller 50 is provided as a hollow cylinder
containing an
internal drive hub 65 and end bearings 66 to enable rotational movement of
roller 50 with
respect to end axles 67, 68 which are fixedly attached to housing 63. Seal
plates 64 are
provided at each end of base section 57 of the roller to contain a bearing and
hub lubricant
and to prevent its contamination. The seal plates provide peripheral seats 64a
for receiving
a sealing means therein (not shown) in contact with the end axles 67, 68. The
drive means
for the roller 50 preferably consists of a reversible hydraulic motor 69, such
as the OMTS
400 low-speed high-torque orbital motor supplied by Danfoss A/S of Denmark.
Hydraulic
motor 69 provides a splined drive shaft 169 for engagement with a
corresponding splined
surface of the drive hub 65.
The feed roller, housing and motor assembly described above results in a
relatively
compact arrangement, due to the hollow nature of the feed roller base section,
which serves
as a lubricant containment means. In this manner, the motor 69 need not be
provided with
an additional casing extension for lubrication of its drive shaft 169, as the
feed roller base
section itself houses the necessary lubricant therefor. As such, the roller,
housing and motor
assembly is rendered more compact, along the direction of the rotational axis
of the feed
roller, than would be the case if the motor were required to have a dedicated
casing
extension surrounding its drive shaft.
With reference to Figures 15 and 16, one of the feed rollers of the workhead
10 may
be provided as a retractable cushion roller 39 in the main body 11 of the
workhead. The
cushion roller is mounted on a housing or swinging arm 156 which is pivotally
connected to
the main body 11 as at 157. Swinging arm 156 is biased to a retracted position
by way of
one or more coil springs 158 or other like means. One end of each coil spring
158 is
attached to the free end 160 of the swinging arm 156, whereas the other end of
each spring
is attached to the main body 11 as at 162. The movement of swinging arm 156
between an
operative position, in which the cushion roller 39 engages a log, and a
retracted position in
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which the log is not engaged, may be achieved by means of a hydraulic actuator
164 or the
like. When the workhead 10 is in a processing mode, such as during delimbing
and
debarking operations, the hydraulic actuator 64 is activated and the cushion
roller 39 is
pushed forward to engage a log being processed. In all other modes of
operation, such as
during felling and grappling, hydraulic actuator 164 is not activated and the
cushion roller
remains in a retracted position due to the biasing effect of coil spring 162.
The mechanism of the retractable cushion roller discussed above ensures
maximum
clamping stability of a tree during felling, handling and carriage, since
retraction of
swinging arm 156 will cause a log held by the jaw arms of the workhead 10 to
be clamped
against portions of the main body of the head, such as the fixed delimbing
knife 27. Thus,
when cushion roller 39 is retracted, the reaction to the forces produced on a
tree stem by the
closed jaw assembly 30 of the workhead is through the tree and onto the frame
of the head,
instead of onto the cushion roller 39. This improves the grappling stability
of the workhead,
especially when a tree is in a vertical position such as immediately following
felling.
Turning now to Figure 17, the details of a measuring device 2 which may be
mounted in the main body 11 of the workhead for measuring the length of logs
to be cut
during bucking operations is next discussed. The measuring device 2 consists
of a toothed
wheel 3 mounted onto the rotatable shaft 4 of a measuring transducer 7 well
known to those
skilled in this art. The transducer 7 is mounted onto a resilient biasing
means, such as a leaf
spring 8 fixedly mounted to an inside surface of main body 11 of the workhead.
This
resilient mounting mechanism is intended to cause the wheel 3 to maintain
contact while
accommodating dimensional variances and surface discontinuities encountered
along the
length of a processed log. A hydraulic actuator 9 may be provided with the
measuring
device 2, and the actuating ram 17 thereof may be extended as shown in Figure
20 against
leaf spring 8 so as to cause the wheel 3 of the measuring device 2 to extend
through
corresponding slot 1 provided in main body 11. This enables the measuring
device 2 to be
retracted when not in use, and a coil spring 18 or the like may be used to
bias the measuring
device to its retracted position. Other measuring devices may be incorporated
for use with
the workhead according to the present invention, for instance, devices which
provide
information as to the diameter or circumference of processed logs along their
length.
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Referring to Figures 18 to 20, the workhead in this second embodiment of the
present invention is particularly suitable for lifting and carrying one or
more logs from one
site to another. The workhead includes a jaw assembly 40 comprising two sets
of
cooperating arms, the first set denoted 41, 42 and the second set denoted 43,
44. The arms
in each of the cooperating sets are slightly off set from one another, with
arms 42, 44 being
shorter in length than arms 41, 43 as best seen in Figure 20. Thus, the arms
42, 44 can
pivotally move within arms 41, 43. Cross-members 45 and 46 join respective
adjacent jaw
arms 42 and 44 and 41 and 43 of each of the sets of arms. The workhead
according to the
embodiment illustrated in Figures 18 to 20 provides the same wrist connection
5 as the first
embodiment of the workhead discussed above. However, the device of Figures 18
to 20
need not be provided with feed rollers 50. The arm arrangement of this device
is such that a
shearing action is produced when closing the arms, the shearing action being
provided by
the relative movement and positions of the cross-members 45 and 46. This
permits the
severance of unwanted plant material such as vines which may need removing
prior to
felling.
A preferred hydraulic circuit for the workhead of Figure 1 of the present
invention is
described with reference to Figure 21. Those skilled in this art will
appreciate that
alternative hydraulic circuit layouts may also be used in order to operate and
control the
various workhead devices mentioned above. The preferred circuit for use with
the present
invention is a load sensing pressure compensating circuit. The circuit
comprises a pressure
compensated hydraulic fluid supply in the form of two main hydraulic pumps
120, each
having a maximum displacement of 2501/min and maximum pressure of 325 Bar. The
pumps 120 are connected through a bank of primary hydraulic valves 122 and
secondary
hydraulic valves 124 to provide preselected rates of maximum fluid flow to
individual
hydraulic circuits associated with each powered device of the workhead. For
instance, the
hydraulic circuit 126 for powering the respective hydraulic motors 165 to 168
associated
with the feed rollers 36 to 39, and the circuit 128 for powering the hydraulic
actuator
mechanism 14 of the coupling means 13 for the workhead, may each be supplied
at a
maximum rate of fluid displacement of 250 1/min. Hydraulic circuit 130, which
serves to
power the cushion roller hydraulic actuator 164, the drive arms 31 and
delimbing arms 21 of
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the jaw assembly 30 and the saw attachment 6, may be supplied at a maximum
rate of fluid
displacement of 180 1/min. Finally, hydraulic circuit 132, which serves to
power the
hydraulic motors 108 which constitute the drive means of the slew bearing 80,
may be
supplied at a maximum rate of fluid displacement of 120 1/min.
A pilot hydraulic pump 121 or the like may be used in the preferred circuit as
a
charge pump to operate the primary hydraulic valves 122 and secondary
hydraulic valves
124 in a manner well known to those skilled in this art. The pilot pump line
includes a
check valve 123. A fluid return line through hydraulic filter 134 to drain 135
is also
provided from the secondary hydraulic valves 124.
Hydraulic circuit 126 for powering the feed roller motors 165 to 168 is
provided
with a four-way flow divider 136 to equalize fluid flow to the roller motors
and thereby
maintain a synchronized rotational speed of the feed rollers, irrespective of
torque demand.
The four-way divider 136 therefore prevents fluid runaway to the feed roller
having the
lowest pressure demand of the feed roller assembly. This ensures that when one
or more
drive rollers momentarily lose contact with a log due to surface
discontinuities or abrupt
dimensional variances as may be caused during the processing of a crooked
tree, the
remaining drive rollers in contact with the log will continue to be
operational at the intended
rate of hydraulic fluid supply. The four-way divider may be in the form of a
single unit, for
instance the Type MH 4 FA supplied by Mannesmann Rexroth GmbH of Germany.
Those
skilled in this art will appreciate that other means may be employed to
accomplish the
equalized flow to the feed roller motors, such as the use of pressure-
compensated
directional control valves, the provision of multiple two-way flow dividers to
achieve the
same four-way equalized flow, or the use of a dedicated hydraulic circuit
furnished with
individual equal displacement pumps for each feed roller motor.
The hydraulic circuit 130 is designed to provide for two distinct and
selectable arm
clamping pressures for various timber processing operations. For instance, in
its higher-
pressure "hard clamp" mode, the drive arms 31 and delimbing arms 21 of the jaw
assembly
may be used to hold a tree in an upright position during felling with the saw
attachment
6, or to grapple one or more processed logs. In its lower-pressure "soft
clamp" mode, the
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arms may be used for delimbing and debarking operations. Each drive arm set
and
delimbing arm set is provided with its own circuit leg, such that the operator
can select a
soft clamp for the delimbing arms and a hard clamp for the drive arms, for
instance, as at
the beginning of the delimbing process to facilitate the required axial
translation of the tree
being processed.
Each circuit leg for the jaw assembly 30 provides a downstream pressure
compensated flow control valve 138 followed by a directional flow valve 140
which is used
to selectively encounter or bypass a pressure reducing valve 142. When
directional valve
140 enables flow to pressure reducing valve 142, the particular arm pair of
the circuit leg
will operate in its soft clamp mode. When the directional flow valve 140
diverts flow from
the pressure reducing valve 142, the particular arm pair will operate in its
hard clamp mode.
A further directional valve 144 is provided downstream of the pressure
reducing valve 142
to enable return flow of hydraulic fluid in each leg of the circuit associated
with an arm pair.
Further downstream of the valves 140 and 144 is an arm actuating valve 146 to
effect the
opening and closing of a particular jaw arm pair by means of hydraulic
actuator 148. A
pressure relief valve 150 is also provided for each circuit leg of the jaw
arms, and a single
check valve 151 is provided for both circuit legs.
Hydraulic circuit 130 further provides a directional flow valve 152 for
extending and
retracting hydraulic actuator 164 associated with cushion roller 39. The
presence of a relief
valve 150 in the circuit 130 allows for the actuator 164 to retract upon an
excessive radial
load being applied to the cushion roller, for instance, as may occur during
the processing of
crooked tree.
A saw attachment actuating valve 154 completes the hydraulic circuit 130. The
valve 154 controls fluid flow to the saw motor 155 and to a hydraulic actuator
(not shown)
for causing pivotal movement of the saw attachment 6 during felling and
bucking
operations. Those skilled in this art will appreciate that where a measuring
device 2 is
employed with the workhead 10, hydraulic supply lines and control valves will
also be
required to activate the extension and retraction of hydraulic actuator 9
associated with the
measuring device. The manner of making such additions to the schematic
hydraulic circuit
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illustrated in Figure 21 will be apparent to those skilled in this art. As
well, it will also be
apparent to those skilled in the art to adapt the hydraulic circuit of Figure
21 for use with the
more simplified workhead according to its second embodiment, as shown in
Figures 18 to
20.
The various actuating, directional, compensating, pressure reducing and relief
valves
provided in hydraulic circuit 130, and shown circumscribed by the rectangle
153 of Figure
21, are preferably disposed on a block manifold located in the main body 11 of
the
workhead, as explained in greater detail herebelow.
Details of the dewing means for the wrist connection 5 of the timber
processing
workhead according to another aspect of the present invention are next
explained with
reference to Figures 22 to 24. The slewing means comprises a slew bearing 80
having a
inner ring 82 and an outer ring 84. The inner and outer rings of the slew
bearing are
concentrically arranged for relative rotational movement, by means of roller
bearings 86 or
the like disposed circumferentially between the respective mating surfaces of
each of the
inner and outer rings. The inner ring 82 is fixedly attached by means of bolts
88 or the like
to a bottom slew plate 90, itself fixedly attached to the main body 11 of the
processing
workhead. The outer ring 84 of the slew bearing is fixedly attached by means
of bolts 92 or
other like fastening means to a top slew plate 94, to which mounting bracket
12 is fixedly
attached, for instance, by means of welded engagement.
The bottom slew plate 90 and top slew plate 94 each respectively provide
centrally
disposed apertures 96 and 98 to enable passage of hydraulic and electrical
control lines for
the various powered devices of the processing workhead, such as the jaw arm
pairs 21 and
31, feed rollers 36 to 39, or saw attachment 6. The preferred means of
supplying hydraulic
and electrical control lines through the wrist connection 5 of the workhead is
that of a
swivel manifold combined with a block manifold, as described in greater detail
herebelow.
The top slew plate 94 further provides two additional apertures 100 to
accommodate
passage of drive means for the slew bearing 80 as next discussed.
The inside surface 102 of inner ring 82 of the slew bearing is toothed for
driven
engagement with the pinion 104 provided at the terminal end of drive shaft 106
of a motor
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108. A second such arrangement of pinion, drive shaft and motor is provided
radially
adjacent the first drive arrangement, the first and second motors 108 being
mounted in their
respectW a apertures 100 provided on top slew plate 94. Preferably, the motors
108 are in
the form of reversible hydraulic motors, which may be of the same type of
hydraulic motors
described above for driving the feed rollers 36 to 39 of the processing
workhead. Those
skilled in this art will appreciate that other forms of drive means could be
utilized for the
slew bearing 80.
A radial protrusion or tab 110 is provided on the top slew plate to prevent
the
continuous rotational movement of the dewing means by acting as a stop means
in
conjunction with a corresponding fixed engaging surface (not shown) located on
the main
body of the workhead. The purpose of the stop means is to prevent the undue
entanglement
or the outright severance of electrical control lines which pass through the
stewing means
by an unchecked rotation of the workhead in the same given direction. Other
stop means for
the stewing means of the workhead will be apparent to those skilled in this
art.
With reference to Figures 25 and 26, the wrist connection 5 of the processing
workhead 10 is associated with a fluid delivery means consisting of a swivel
manifold 170
for through passage of hydraulic supply lines and electrical wiring for
controlling and
driving the various powered devices of the workhead. Swivel manifold 170
comprises an
internal substantially cylindrical rotor portion 171 whose outer surface is
provided with a
plurality of circumferential fluid receiving or fluid egress channels 172a to
172d. Each of
the channels 172a to 172d is sealed by adjacently disposed pressure seals (not
shown)
located in circumferential seats 173. The channels 172a to 172d are each in
respective fluid
communication with corresponding through passages 174a to 174d which direct
fluid flow
to or from the circumferential channels to respective interface ports 175a to
175d provided
on the underside of the rotor 171.
The rotor 171 is encased with an outer cylindrical sleeve portion 176, whose
lower
terminal end 178 provides a peripheral seat 180 therearound for receiving a
sealing means,
such as an O-ring seal (not shown). To the upper terminal ends 182 of the
sleeve 176 is
fixedly attached an end plate 184. The end plate 184 provides respective top
and bottom
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annular channels 186 and 188 for receiving thrust bearings (not shown), well
known to
those skilled in this art. The end plate 184 has a central opening therein
which provides a
seal seat 190 for receiving a sealing means (not shown), such as an O-ring
seal. Sleeve 176
is secured against the rotor 171 by means of an end plug 192 which may be
threadedly
engaged to the rotor. End plug 192 provides a seal seat 194 on its outer
surface
corresponding to seal seat 190 of end plate 184. A cap plate 196 is removably
attached to
rotor 171 by means of screws 198 or the like to complete the swivel manifold
assembly.
Sleeve 176 is provided with fluid inlet or outlet ports 200a to 200d which are
in
respective fluid communication with the circumferential channels 172a to 172d.
Each of
the circumferential channels of the rotor portion is in constant fluid
communication with its
respective port of the sleeve portion throughout relative rotational movement
of the rotor
and sleeve. Hydraulic fluid supply or return hoses 202a to 202d are connected
to the
respective ports 200a to 200d (Figure 26). The swivel manifold 170 is
associated with a
fixed or block manifold 206 and is mounted thereon by means of mounting screws
208 or
the like provided through a bottom annular connecting flange 210 of the rotor
171. The
block manifold 206 is itself fixedly mounted within the main body 11 of the
workhead 10,
such that the swivel manifold 170 extends outside of the main body 11 of the
workhead
along slew axis BB' (Figure 4) through the respective apertures 98 and 96 of
the bottom
slew plate 90 and top slew plate 94 (Figure 22).
Manifold block 206 is provided with appropriate internal passages in fluid
communication with the interface ports 175a'to 175b of rotor 171. One such
passage 225 is
shown in Figure 25. The internal passages are in turn in fluid communication
with a desired
number of manifold inlet or outlet ports, as at 212 and 214, for hydraulic
connection to the
various devices of the workhead. For instance, outlet port 212 of the block
manifold 206 is
connected to the four-way flow diverter 136, itself connected to a plurality
of hydraulic
supply hoses 216 for each of the feed roller motors 165 to 168 of the workhead
10. Inlet
port 214 is for returning hydraulic fluid from the feed roller motors.
Various actuating valves 146 and 154, flow control valves 138, directional
valves
140 and 152, pressure reducing valves 142 and relief valves 150 of the
hydraulic circuit for
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the workhead 10, collectively denoted as hydraulic control valves 224 in
Figure 25, may be
mounted directly onto the underside 218 of the manifold block 206 in fluid
communication
through the manifold block with the appropriate interface ports 175a to 175d
of the swivel
manifold 170. Where the hydraulic control valves 224 of Figure 25 are mounted
directly
onto the manifold block as mentioned above, those skilled in this art will
appreciate that the
various hydraulic fluid supply and return lines traced in the hydraulic
circuit of Figure 21,
and shown bounded by rectangle 153 thereof, are provided as respective
internal passages
within the manifold block 206. For instance, inlet and outlet passages will be
provided in
the manifold in respective fluid communication with inlets and outlets of the
hydraulic
valves, so as to avoid the need for hose connections to the valves.
A wiring passage 204 is provided in the rotor 171 and end plug 192 for housing
and
transmission of electrical wiring 226, which is introduced through the swivel
manifold 170
by means of an aperture 220 (Figure 25) provided in cap plate 196 along slew
axis BB'
(Figure 4). As well, electrical wiring received from passage 204 of the swivel
manifold
may be passed through the manifold block 206 for connection to an electrical
terminal strip
222 which may also be mounted on the underside 218 of manifold 206.
By furnishing a larger surface area for the various hydraulic and electrical
connections, accessibility for maintenance purposes is enhanced by use of the
manifold
block 206. As well, by providing a swivel manifold in conjunction with a block
manifold,
hydraulic supply hoses to the workhead 10 may be shortened, since there is no
need for the
rotational movement of the wrist connection to be accommodated by slack in the
supply
hoses. This results in a compact design which minimizes hose chaffing and
snagging
during field use of the workhead 10.
Finally, those skilled in this art will appreciate that the inventive concept
in any of
its foregoing aspects can be incorporated, adapted or modified in many
different
constructions, so that the generality of the preceding description is not to
be superseded by
the particularity of the attached drawings. Thus, various alterations,
modifications and/or
additions may be incorporated into the various constructions and arrangements
of parts and
devices described herein without departing from the spirit or scope of the
present invention.
20652408.1
