AU653396B2 - Debarking apparatus - Google Patents

Description

AUSTRALIA

Patent Act COMPLETE SPECIFICATION

(ORIGINAL)

Class I 53 96 nt. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: Names(s) of Applicant(s): cc PATRICK RANSLEY KIM RANSLEY and R.R. L.A. FENTON Actual Inventor(s): PATRICK RANSLEY Our Address for service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street MELBOURNE, Australia 3000 Complete Specification for the invention entitled: DEBARKING APPARATUS The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 0804N 0804N DEBARKING APPARATUS The present invention relates generally to an apparatus and a method for the debarking of trees, and more particularly to the debarking of trees that utilises the impact energy from rotating flails to remove bark and small limbs from the trunks of fallen trees. The present invention also resides in a chain flail that is suitable for use in the debarking appratus of the invention.

As used herein, the term "debarking" refers to removal of material from a tree trunk and is primarily concerned with the removal of bark, but it should be understood that it includes the removal of small limbs or other growths that may occur on such tree trunks. It will be convenient to refer to such tree trunks as "logs" throughout the description and claims, and to use this term for all stages of processing.

Typically, logs are debarked before undergoing any subsequent conversion process, regardless of whether the log product is to be used for lumber, veneer for plywood manufacture or chips for pulp manufacture. Preliminary steps such as debarking and delimbing are both time consuming and expensive yet are a necessary part in the processing of forestry products to ensure quality products.

Various processes and apparatus have been used both for the debarking and delimbing of logs. For example, when delimbing large logs, workmen may continue working with chainsaws to simply cut the limbs while still in the forest.

Logs may then be hauled to a debarking site for further processing.

Various forms of debarking processes and apparatus have been used in the forestry industry. For example, the use of high pressure water jets has been used in areas where an ample water supply is available. Water may be used from such sources as lakes, rivers or the sea, and although it may be recirculated, it is ultimately returned to the original source. This will lead to ultimate contamination of the water supply.

Further types of debarking apparatus and processes 39 include ring type debarkers having a rotating ring with WDN 2 knives scraping the bark from the logs, or flail type debarkers, where rotating flails, which are most commonly a metallic chain or rope, remove the bark by high energy impact on the bark. Both the ring type debarker and flail debarkers usually utilise a conveyor belt to pass the tree longitudinally through the debarking mechanism of the machine, with only a portion of the tree being worked on at any particular time. This is generally a slow process and difficulties may arise as the bark fibre must be broken during the removal process, particularly if the bark is fibrous or string like.

It would be convenient if an apparatus and a process could be used where the length of the log is worked upon at the same time thus allowing for a quicker debarking process.

It is an object of the present invention to overcome or at least alleviate one or more of the difficulties associated with the prior art.

•The present invention resides in a debarking S. .apparatus including; 20 a housing having an inlet and exit means; at least one rotatable member located centrally defined orientation; and a plurality of laterally spaced flail members i 25 arranged around the rotatable member, wherein the housing is formed to; receive a plurality of logs in an orientation substantially parallel to the orientation of the axis of the rotatable member, allow said logs to fall from the inlet means, to strike the rotatable member and/or flail members, and maintain said logs in said orientation when the logs strike the rotatable member and/or flail members, and allow the logs to fall to the exit means.

The defined orientation of the logs and the axis of the rotatable member, may generally be considered a "lengthwise orientation. Such an orientation will allow .1,1 the log to strike the flails of the rotatable member in a t 9 manner such that the entire length of the log will strike t-3at once.

log.

That is, there will be a "total strike" of the *9 6 a a.

a Most preferably, the housing consists of two chambers forming the interior of the housing, each chamber having a centrally located rotatable member, each having a plurality of laterally spaced flail segments, with the flails being arranged in a plurality of rows. With such an arrangement, t WDN 3cthe housing is such that each rotatable member may be placed so that they are substantially vertically adjacent each other. In a preferred configuration, each rotating member m:iy be slightly offset from a vertical alignment. It should be understood however, that depending upon the need, ie.

size, thickness of bark and quantity of logs the housing may contain more than two rotatable members, however it would be convenient to describe the invention simply in these terms.

The flail members may be formed from any suitable material, such as rope, steel wire or chain segments.

Preferably each of the laterally spaced flail members are chain segments and may be any suitable chain commonly used for such purpose such as a standard linked chain. The length of each flail member, the number of flails in each row, and the number of rows arranged around each rotatable member may vary depending on the needs. Typically, the length of each flail member will approximate the diameter of the log to be deb-rked but may typically vary from 10cm to 2m. Each flail member may typically be approximately 5-20cm apart and the rotatable member may typically have up to 30 rows arranged on it, preferably between 15 and 30. Any number of flail members may however be used to suit the type of log and size of the apparatus.

The rotatable member itself, may be a drum surrounding :'25 a central axle with the flail members anchored to the exterior of the drum. Typically, a drum may be approximately 2 metres long, however, it is prefered that the apparatus is arranged such that additional drums, with flail to tmembers may be added. A typical arrangement for the apparatus when processing large logs may be to have up to 7 or 8 drums, preferably between 6 to 9, arranged around a centzal axle, so the rotatable member has a combined length of approximately 12 to 18 metres, preferably 14 to 16.

Alternatively, a single drum of an extended length, preferably up to 12 metres long may also be used.

The flail members may be anchored to the drum in any manner such as by direct welding or connection through a hook to the outer surface of the drum. As an alternative, the 39 drum may have associated with it a band, preferably made of WDN 4 steel, that is formed around the circumference of the drum.

The band may serve two major roles. Firstly, by use of a pin means, such as a bolt or piece of dowell or like object through the band it may be used to anchor the flail member to the rotating member. The anchor site may be between two bands in such a manner that the site of anchor is protected from contact with the log. This may have the effect of extending the life of the flail member. The bolt or dowell may easily be removed and replaced if suffering from excessive wear. Secondly the band itself may assist in debarking the log as it forms a working surface on the drum to act upon the log.

In operation, the rotatable member may rotate at between 100 to 1000 revolutions per minute. The chain flails themselves that may be used are generally from 20 cm to 2 metres long. It has been found that during operation, the chain is subject to many stresses due to the high intensity of revolution and the volume of logs that may be processed through the debarking apparatus. As a result, the chains are subjected to wear, particularly at those links of the chain that will strike the log most.

It is envisaged that the most preferred flail member used in the debarking apparatus would be a linked standard chain. In a most preferred form, each link of such a chain 2: 5 may simply be described as a substantially flat oval shaFr having a particular plane of orientation. The chain is so formed so that each link connects to the next link and its rounded end. By the very nature of this formation, the rientation of each consecutive link may be considered to be at 900 to its neighboring link.

When used in the debarking apparatus during operation, the chain is usually utilised in such a manner so that the chain provides a working surface to act upon the log to be debarked. That working surface will consist of the chain in one particular orientation. The links of the chain may be considered to be in the distinct planes of orientation. For ease of description, it should be considered that one plane of orientation is parallel to the surface of the log, while 39 the other plane is at 900 to the surface of the log. During WDN 5 use, it is only those links that are in a plane of 900 to the surface of the log that will actually strike the log. Those links that are in a parallel plane, will be protected from striking the log due to the nature of the chain configuration.

Although, standard linked chains are contemplated for use with the debarking apparatus, trials have found that during the rotation of the standard linked chain flails, that the log is first struck by the corner of a particular link that is closest to the rotational centre. This constitutes a small surface area of a particular link that initially strikes the log and it has been found that this may lead to damage or bruising of the log during processing.

Further, as only a small section of the chain segment provides the working surface of the log, it has been found that the chains tend to wear relatively quickly at this striking point.

Still further, as a result of only a relatively small portion of each chain that may strike a log, the stripping time of a log has not been maximised.

A most suitable flail member, that is suitable for use in an apparatus according to the present invention comprises a standard linked chain having a plurality of substantially planar links; each consecutive link having a plane of orientation 5 substantially perpendicular to its neighbour, said links in a first orientation providing a working surface; said links in a second and perpendicular orientation having at least one abutment member associated with one or more links; said abutment member being of a size and orientation to increase the working surface of the flail member.

Most preferably, each link is of a substantially oval shape having straightened sides and a particular plane of orientation. The chain may generally be formed as a standard linked chain such that each consecutive link may be considered to be at a 900 orientation to its neighbor.

A working surface is generally provided by the links in a first particular orientation of the chain, the working 39 surface being that surface of the chain that will strike the WDN 6 log during operation in the debarking apparatus. It may be considered that those links that lie in a plane of approximately 900 to the plane of the surface of a log, will provide the working surface as they will strike the log, while those links that lie in the plane parallel to the surface of the log will be prevented from striking the log 1 to the protection provided by the orientation of its •.ghboring links.

The abutment member of the present invention is formed so as to increase the working surface of the chain that is presented to the surface of the log in operation. It is most preferred therefore that the abutment member is associated with those links that during operation in the debarking apparatus will lie in a plane substantially parallel to the plane of a log, to enable these links to be utilized during the debarking operation.

:"!The abutment member itself may be either integrally formed with a link or may be welded to the link. The abutment member should be of such a shape and size so that it provides a surface for the link that will lie substantially flush with the working surface of its neighboring link. It has been found that an abutment member that is of a similar cross sectional dimension to the material that is used to form the links is most suitable.

It is preferred that the abutment member be formed or connected to straightened side edges of a particular link.

If formed or connected in this position, the abutment member will not interfere with the connection between each link and therefore will not interfere with the inherent flexibility of the chain.

It is further preferred that the abutment member be bevelled or rounded at one end, most preferably the end closest to the rotatable member of the debarking apparatus in use as it has been found that in operation, it is this point that will strike the log first. It is preferred to round or bevel this part of the abutment member so as to at least minimize the damage or bruising that may be caused to a log during stripping.

39 Most preferably the chain segment includes a sleeve WDN 7 member at one end to which a first link may be integrally formed or attached. The sleeve member provides a means to anchor the chain segment to the rotatable member, by use of a removable pin passed through the sleeve member and adjacent body surrounding the rotatable member. The pin may be readily removed, so as to allow for replacement of the chain segment.

The orientation of the chain segment within the debarking apparatus should be such so that when in operation the abutment members associated with one orientation of links and a surface of the remaining links will all be capable of striking a log during processing. The increase in the working surface of the chain should be capable to increase the efficiency of the debarking of the logs.

The invention further resides in a process of debarking logs, wherein said process includes; orientating a log in a lengthwise orientation and allowing the log to strike a rotatable member having a plurality of laterally spaced flail members mounted on said rotatable m nber, S. said orientation of the log allows for a total strike of the log along substantially its entire length.

The term "total strike" as used herein and in the .2:'25 claims refers to the entire length of the log, or a o substantial proportion thereof, being struck by the flail members at substantially the same time.

The construction of the housing is generally reinforced steel plate, able to withstand stresses associated with movement of the logs during the process.

As the apparatus allows for gravity feeding of the logs, a number of logs may be inserted at a single time.

This also improves the speed in which logs may be debarked and convenience allowing for ease of processing if the logs are transported for example by road to the debarking site.

Restrictions, such as suitable bevilles within the interior of the chambers may be added to slow down the processing of a log. The flails and the drum size themselves 39 may also be adjustable to suit any sort of log to be

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-8processed. Typically, the flail length and the log and drum diameters are approximately the same size.

The apparatus may be accomodated to debark any size and shape of a log. Preferably, there is sufficient flexibility in the flag's to cope with bends in the log. The flail length may also be adjusted if smaller logs are to be debarked.

In the following description the invention will be more fully described with reference to the accompanying drawings. It should be understood that the drawings are merely illustrative and should not be taken in any way as a restriction of the generality of the invention described above.

Figure 1 illustrates a cross section of a debarking apparatus according to the present invention.

Figure 2 illustrates an arrangement between two rotatable members that may be used in the apparatus of the present invention.

Figure 3 illustrates an arrangement of individual flail members around the rotatable member.

Figure 4 illustrates a further embodiment of a cross section not drawn to scale of a rotatable member, having flail members segments attached to a steel band.

Figure 5 illustrates a view of a preferred chain segment with anchoring member.

Figure 6 illustrates a perspective view of a partial segment of the chain of figure Figure 7 illustrates a cross-section through line III-III of figure 6.

Figure 8 illustrates a side view of a partial segment of a chain in accordance with the invention.

It will be convenient to describe the apparatus in general terms with reference to figure 1. Figure 1 illustrates a debarking apparatus having an inlet means The apparatus is substantially arranged in a vertical manner such that the inlet means is located above the working mechanism. The inlet means may be of any suitable arrangement but preferably such that it assists in aligning 39 the logs so that they are able to drop through the WDN 9 debarking station in a length-wise orientation. For example, the inlet means may consist of a "trap door" type arrangement that releases the logs when aligned in a correct orientation.

As an alternative to such an inlet means, the logs may be orientated by the housing means itself. For example, once the log has reached the working mechanism, that is the rotable member with flail members, the impact of the flail members combined with the internal walls of the housing may orientate the log in a suitable lengthwise orientation. The force of the rotating flail members will force the logs to rebound off the interior wall of the housing assisting in the correct orientation.

The apparatus illustrated in figure 1 shows two separable debarking chambers and defined by the walls of the housing Orientation of the logs is .:particularly prevelant in the area designated as in figure 1. Each chamber contains a centrally located rotatable member and (11) in a substantially vertical orientation consisting of a drum (17) and (18) with flail members and (10) conencted to the drums. Only one flail member is illustrated, however the drum of a rotating member may contain up to 30 rows of such flail members surrounding the drum. Such an arrangement is best illustrated in Figure 3.

It is most preferred that the rotable members are slightly offset for ease of passage of the logs past both rotatable members. The rotatable members may be driven by an axle means connected through the drums and connected to any suitable drive mechanism. This is best illustrated in figure 2 with axle (15) and (16) passing through drums (17) and (18) connecting to a drive mechanism. The drive mechanism (not illustrated) may be any suitable means, such as diesel or electrically powered motor. Most preferably the drive mechanism is portable and qelf generated for use in remote areas. A typical suitable revolution for the rotatable member is between 100 to 1000 revolutions per minute when at full operable speed. The rate of revolution may vary depending upon the drum diameter, so as to maintain an optimum 39 revolution rate.

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10 A log may fall into the first debarking chamber where, as illustrated in figure 1 the rotatable member rotates in a clock wise direction. The rotatable member should be rotating at sufficient revolutions, such that when in operation, upon meeting the flail member the high impact removes substantially all the bark in a single total strike.

A single total strike of the entire length of the log assists in removing the bark as the flails act on the complete bark fibre, and do not have to tear or break the bark fibre. The outward force acting upon the log may cause some rotation of the log assisting in overall removal of the bark.

The apparatus may be adapted so that the log leaves the apparatus aftcer passing through a single debarking chamber, however it is most desired that at least two chambers be arranged in substantially vertical orientation.

Further chambers may also be used. It is most preferred that the two rotatable members are of such a distance apart to both assist in maintaining the movement of the log. A desired relation between the flail members of two rot-atable members is best illustrated in figure 2. The shape of the housing may also assist the movement of tho logs passing to the second debarking chamber, where a ramp type means (12) assists in directing the logs. Upon reaching the section between the two rotatable members, the second rotatable member is illustrated rotating in an anti-clock wise direction. The force of the flail members is sufficient to maintain the momentum of the logs and continue it on a path *through section of the second debarking chamber S. within the apparatus. Removal of the bark may be substantially completed in this section as the reverse side to the log may be worked upon given the different rotation of the second rotatable member. The log may then pass out through exit means and removed in any convention manner.

The removed bark and small limbs will eventually pass out the same exit.

Figure 2 illustrates a preferred arrangement between the two rotatable members. Most preferably, the flail members are offset in a longitudinal manner to avoid striking 39 each other and assist in maintaining the momentum of the WDN 11 logs. Any arrangement of flail members is however suitable. Each drum may be rotated by axle (15) and (16) respectively.

Figure 3 illustrates a typical arrangement of flail members upcn the rotating member. A sufficient number of rows of flail members should surround the rotatable member to ensure that the log does not cause the flail members to collap-a. In a sence, it is most desired that there are sufficient flails, rotating at a sufficient speed to act substantially as a solid wall against a log.

Figure 4 illustrates an alternative arrangement for the flail members surrounding a rotatable member. Drum surrounds axle with drum (20) having a band (22), surrounding its outer perimeter. The flail members (23) are attached to the band by a bolt By this means the connection between the chain and rotatable member is Sprotected from contact with the log The band may also assist in stripping the bark from the log as surface (26) may act as a working surface.

Figure 5 illustrates a preferred chain (31) for use in the present invention. This chain consists of interlocking link members (32) and each having a planer orientation perpendicular to each other. The relationship between each link member is probably best illustrated in figure 7, where a link member (32) is at a 90° angle to link member The planer orientation of each link is illustrated by lines 2' and 3' respectively. By the very nature of the chain, some rotational movement will exist between the respective link members (32) and The chain segment itself can be of an indeterminent length and as illustrated in figure 5, is attached to an anchoring member The anchoring member provides the first link 5 in the chain.

An abutment member (36) is associated with each link member in the 3' planer orientation. In use, the abutment member should be associated with those link members that will lie in a planer orientation substantially parallel to the surface of log that is being processed by the debarking apparatus.

39 The abutment member is illustrated as being formed

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12 integrally with the link member. The abutment member has a similar cross section dimension to the cross section dimensions of each link member. This is again best illustrated in figure 7. It is preferred that the abutment member is of such dimensions so that its positioning in association with the link member creates a relatively level plane with the neighboring link member. Again, this can best be seen along line V-V in figure 7 and in figure 8.

The abutment member may however be welded to an already existing chain segment. For ease during construction, the weld is usually associated with the outside edge of each link member.

The abutment member is bevelled (37) at one end to eliminate sharp edges associated with the abutment member.

1 5 In use, the bevelled end is close to the rotatable member of the debarking apparatus, as due to the rotational forces, it has been found that it is at that point that the chain will strike the log first.

The chain segment may be attached to the debarking apparatus by an anchoring member (34) illustrated in figure The anchoring member consists of the first link member associated with a sleeve The first link member (35) may be of a slightly wider cross sectional dimension as it has been found that there is relatively rapid wear at the connection between this link and its neighboring link (39).

A pin may be inserted through thz sleeve member (39) to attach the anchoring member to the debarkinc apparatus. The anchoring member may be attached to a band (22) of the debarking apparatus.

The apparatus and process of the present invention allows for a suitable substantially non-polluting and quick means by which bark may be removed from a log. The logs themselves may be processed by gravity feeding the logs into the apparatus. This means little energy is required to drive the logs through the apparatus providing substantial savings in energy. The logs, once debarked may be removed by conventional means, ready fLr transportation and further processing.

39

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13 The above description illustrates the preferred embodiments of the invention and any modification or alteration thereto without departing from the spirit of the invention should also be contemplated.

S

o 39 39

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14

Claims (16)

1. 3. A debarking apparatus according to claim 1 or claim 25 2, wherein the flail members are arranged around the rotatable member in rows extending longitudinally around the outer perimeter of the rotatable member, and are ""*anchored to the rotatable member.
2. 4. A debarking apparatus according to any one of claims 1 to 3 wherein the length of each flail member is approximately the length of the diameter of the log to be debarked, and the flail members are spaced between 5 to cm apart. A debarking apparatus according to any one of the preceding claims wherein the rotatable member has between to 30 longitudinal rows of flail members arranged around S39 the outer perimeter of the rotatable member. WDN 15
3. 6. A debarking apparatus according to any one of the preceding claims wherein said rotatable member consists of a plurality of drums arranged end to end around a common longitudinal axis.
4. 7. A debarking apparatus according to claim 6 wherein the rotatable member includes between 6 and 9 drums having a combined length of from 12 to 18 metres.
5. 8. A debarking apparatus according to any one of the preceding claims wherein the flail members are formed from rope, steel wire or chain segments.
6. 9. A debarking apparatus according to any one of the preceding claims wherein the rotating member further includes a plurality of bands, formed around the circumference of the rotating member; said flail members include an anchoring means to S• anchor said flail members between two adjacent bands. 02 A debarking apparatus according to claim 9 wherein said anchoring means is provided by a removable pin passed between two adjacent bands; and a sleeve member associated with one end of said 25 flail member. S.
7. 11. A debarking apparatus according to any one of the preceding claims wherein the rotating member, in use, is able to rotate at between 100 to 1000 revolutions per minute.
8. 12. A debarking apparatus according to any one of the preceding claims wherein the apparatus includes two rotatable members, arranged in said housing to be substantially vertically adjacent to each other.
9. 13. A debarking apparatus according to claim 12 wherein each of the rotatable members are arranged slightly ofset from vertical from each other. WDN 16
10. 14. A debarking apparatus according to claim 12 or 13 wherein each rotating member in use will rotate in an opposite direction.
11. 15. A flail member, when used in a debarking apparatus according to any one of the preceding claims, wherein said flail member consists of a standard linked chain having a plurality of substantially planar links; each consecutive link having a plane of orientation substantially perpendicular to its neighbour, said links in a first orientation providing a working surface; said links in a second and perpendicular orientation having at least one abutment member associal with one or more links; said abutment member being of a size and orientation to increase the working surface of the flail member.
12. 16. A flail member according to claim 15 wherein said links in said second orientation include two abutment 20 members, arranged in parallel and on opposite parts of said link; each abutment member being of a size and shape to provide a surface for the link that is substantially flush with the working surface of a link in said first •t 25 orientation. 00
13. 17. A flail member according to claims 15 and 16 wherein the abutment member is of a cross-section substantially the same to the cross-section of the material that is used to form the link.
14. 18. A flail member according to any one of claims 15 to 17 wherein the abutment member is substantially cylindrical shaped and is bevelld at one end, which in use, in conjunction with the debarking apparatus according to any one of claims 1 to 12, is the end that is positioned to first strike a log. 9" 1't9. A flail member according to any one of claims 15 to WDN 17 18 wherein a sleeve member is formed integrally with the first link of said chain segment. A flail member according to claim 19 wherein said chain segment is anchored to a debarking apparatus according to any one of claims 1 to 14 by a removable pin that is passed through said sleeve member and adjacent band to anchor said chain segment to said bands.
15. 21. A process of debarking logs, wherein said process includes; providing an apparatus according to any one of claims 1 to 14, orientating a log in an orientation substantially 15 paralle. to tne orientation of the longitudinal axis of the rotatable member, and allowing the log to strike the rotatable member and/or said flails in said orientation. e9
16. 22. A debarking apparatus according to claim 1 substantially as hereinbefore described with reference to any one of the drawings. **b *g 23. A chain segment acccrding to claim 16 substantially as hereinbefore described with reference to any one of the 999 25 drawings. 9. DATED: 11 July 1994 PHILLIPS ORMONDE FITZPATRICK Attorneys for: PATRICK CHARLES RANSLEY KIM RANSLEY and R.R. L.A. FENTON 7448N 39 WDN 18 ABSTRACT A debarking apparatus comprising; a housing having an inlet and exit means; at least one rotatable member located centrally within the housing; and a plurality of laterally spaced flail members arranged around the rotatable member, wherein the apparatus is adapted to receive a plurality of logs in a lengthwise orientation and to allow a passage for the logs from the inlet means to strike the rotatable member in a lengthwise orientation. S. 39 5972N WDN