CA1285291C - Process and an apparatus to feed tree trunks to a processing machine - Google Patents
Process and an apparatus to feed tree trunks to a processing machineInfo
- Publication number
- CA1285291C CA1285291C CA000532683A CA532683A CA1285291C CA 1285291 C CA1285291 C CA 1285291C CA 000532683 A CA000532683 A CA 000532683A CA 532683 A CA532683 A CA 532683A CA 1285291 C CA1285291 C CA 1285291C
- Authority
- CA
- Canada
- Prior art keywords
- centering
- tree trunk
- groups
- rolls
- trunk
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Abstract
ABSTRACT OF THE DISCLOSURE
Tree trunks that are to be fed into processing machinery pass through a plurality of groups of centering rollers that can be positioned symmetrically. The centering rollers that are located at the start and the end of the trunk are moved into position on the tree trunk.
Subsequently arranged milling heads produce guide surfaces on the tree trunk, on which the tree trunk is supported and guided by guide bodies immediately thereafter.
Tree trunks that are to be fed into processing machinery pass through a plurality of groups of centering rollers that can be positioned symmetrically. The centering rollers that are located at the start and the end of the trunk are moved into position on the tree trunk.
Subsequently arranged milling heads produce guide surfaces on the tree trunk, on which the tree trunk is supported and guided by guide bodies immediately thereafter.
Description
The present invention relates to a process for feeding tree trunks to a processing machine by means of centering elements, each of which can be adjusted to be arranged symmetrically to the centre line of the processing machine, a plurality of guide surfaces that are opposite each other being milled on the trunk before it enters the processing machinery, these then immediately engaging with guide elements.
Tree trunks that are to be processed into beams, s~uare lumber, boards and, in some cases, into usable chips and shavings, in processing machinery such as sawmills and shaping machinery, must be fed into said processing machinery in a straight line, such that the centre line of the feed path coincides precisely with the centre line of the tree trunk, so as to permit optimum utilization of the wood. Any oscillation of the tree trunk has to be prevented as far as possible, for otherwise the cuts are not made in an accurate, straight line.
In order to permit such precise, rectilinear feeding of tree trunks into a processing machine, it is known that guide surfaces can first be milled on the tree trunk; these guide surfaces are rectilinear and make it possible to guide the tree trunk in a straight line along such surfaces as it is being fed into the machinery. This means that the difficulties that result from using the conical and usually curved shape of the outer surface of the tree trunks as guide surfaces can be overcome in the immediate vicinity of the processing machinery; in actual fact, this difficulties are only set aside, for the tree trunk must be guided in a straight line in alignment with the centre axis of the tree trunk in order to mill the guide surfaces.
In a known process (DE-PS 29 21 458), in order that this can be done the tree trunks are picked up in the central area and at the ends by centrally positionable grippers, each of which is supported on a slide that can be moved along a rail. The tree trunks that have been so picked up are moved to milling machines that mill the processing surfaces on which the tree trunks are then guided by means of guide rollers. As soon as the start of the tree trunk i8 picked up by these rollers, the centre gripper opens; the tree trunk is then guided between the guide rollers and the rear gripper. The trunk that is so guided and partially processed is passed to a processing system in which the tree trunk is milled to a cylindrical shape.
There is a further support on this cylindrical surface, while the tree trunk, processed on all sides, is passed to a plurality of feed rollers that are arranged at the input to a subsequent processing machine, such as a saw, for example.
The installation required for this known process is relatively complex. The slides that bear the grippers and which can be moved along the rails have to be returned to their starting positions once a tree trunk has passed and then be loaded before they can move the next tree trunk into the system. This means that that very close limits are i285~91 imposed on the operating rates that can be achieved. Using the known process, in order to permit precise guidance of the tree trunk at the intake of the processing machinery two guide surfaces must be milled on one after the other in two processing stages, which is to say, one for the initial guidance of the start of the trunk, and the other to achieve the cylindrical outer surface prior to entering the group of guide rollers at the start of the processing machinery.
For this reason, it is the task of the present invention to create a process of the type described in the introduction hereto and which permits a rapid operating cycle and precise feeding of the tree trunks into a processing machine at very little cost and in a labour-saving manner.
In addtion, the present invention is intended to create an apparatus that is suitable for carrying out the aforesaid process.
According to the present invention, this task has been solved in tht a plurality of groups of centering rollers--at least some of which can be driven--arranged sequentially in the direction in which the tree trunks are moved are so controlled when a tree trunk is fed in that the centering rollers of the groups through which the start and the end of the trunk is moving are adjusted symmetrically, whereas the centering rollers of the remaining groups remain in their withdrawn or unloaded position, respectively.
~.28529~
In contrast to the grippers that move with the tree trunk, in the process according to the present invention the individual groups of centering rollers remain fixed in place. The only locations that move forward with the tree trunk are those at which the centering rollers support the tree trunk symmetrically to its centre line. This support is effective at the ends of the tree trunk during the whole of the feed process, i.e., all the groups of centering rollers through which the end of the trunk moves in sequence guide and support the end of the trunk. The front of the trunk is supported and guided by the group of centering rollers through which it is passing only until it is introduced into the machine that mills on the guide surfaces, which are then supported immediately afterwards by the guide elements.
In this feed movement the tree trunk can be fed to the processing machinery, for example, a saw, immediately afterwards, without any need to support it between guide rollers. The whole operating cycle can be continuous, for the start of a subsequent trunk can abut directly on the end of a preceding trunk. This permits very high operating speeds.
It is known that in order to feed tree trunks to processing machinery, centering rollers that can be positioned centrally from opposite sides (DE-OS 16 28 866).
Here, however, the centering rollers are arranged in two ` 128S~L
fixed groups through which the trunk moves. If the trunk is curved, it will oscillate.
It is also known to use a roller bed in feed systems for wood processing machinery, said bed supporting the tree trunk (DE-OS 32 46 969). Here, however, the tree trunk is guided along its lower surface line, so that in general it is impossible to align lt centrally with the centre feed line of the processing machinery.
According to a broad aspect of the invention there is provlded, in a process of feeding tree trunks to a processing machlne, the process including the step of cutting guide surfaces into the tree trunk at a cutting station disposed upstream of the processing machlne whereafter the guide surfaces are engaged and supported by guide elements disposed between the cutting station and the processing machine, the improvement comprising centering the tree trunk along a centering line of the processing machine during the delivery of a tree trunk to the cutting station by the steps of:
providing groups of centering rolls upstream of said cutting station, said groups being spaced along said centering line, centering rolls of each said group being adjustable symmetrically between trunk centering and trunk non-centering modes, at least some of said centering rolls being driven to advance a tree trunk, and advancing the tree trunk along said centering line successively through said groups of centering rolls while successively adjusting said groups between their centering ar;d 6a non-centering modes such that groups thereof located to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group disposed therebetween is in a non-centering mode.
According to another broad aspect of the invention there is provided apparatus for processing tree trunks comprising a processing machine defining a centering line, cutting means disposed upstream of said processing machine for cutting guide surfaces into a tree trunk, guide elements disposed between said cuttlng means and said processing machine for engaging and supporting the guide surfaces durlng travel of a tree trunk to said processing machine, the improvement comprising centering means for centering a tree trunk along said centering line during the delivery of the tree trunk to said cutting means, said centering means comprising:
groups of centering rolls disposed upstream of said cutting means, said groups being spaced along said centering line, centering rolls of each sald group being adjustable symmetrically between trunk centerlng and trunk non-centering modes, means for driving at least some of said centerlng rolls for advancing a tree trunk successively through said groups of centering rolls, and means for successively adjusting said groups between thelr centerlng and non-centering modes such that groups ~: thereof arranged to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group : disposed therebetween is in a non-centering mode.
B
` ~ ~85291 6b An advantageous systeln ~or carrying out the process is described in greater detail below on the basis of the drawings appended hereto. These drawings are as follows:
Figure 1: A side view of an apparatus for feeding tree trunks to a saw;
Figures 2 to 4: The apparatus as in Figure 1, in sequential steps of the feed process;
Figure 5, An enlarged partial cross-section on the line V-V in Figure 4;
Figure 6: A partial view in the direction indicated by the arrow VI in Figure 5.
The feed apparatus shown in the drawings has a chain bed 2 ~hat can be raised by means of the parallel arms 1 and can 1.28529~
be driven, the tree trunk 3 that is to be processed is moved on this chain bed 2. Above the exit end of the chain bed 2 there is a follower roller 4 that is so arranged that it can move vertically; this roller is connected to a measuring system (not shown herein). As soon as a tree trunk 3 lies in the position on the chain bed 2 that is shown in Figure 1 it is raised until a signal that is emitted from the follower roller 4 indicates that the centre of the tree trunk 2 is close to the centre feed line. The chain bed 2 is fixed at this level, while the tree trunk 3 is moved ahead. As is shown in Figure 2, the tree trunk 3 passes through a plurality of groups 5 - 10 of centering rollers 11 arranged in sequence one after the other, each of which can be arranged symmterically to the centre feed line 12.
Figure 5 shows that each group 5 - 10 of centering rollers 11 is has two centering roller 11 pairs that are opposite. The centering rollers 11 that can be driven individually from the drive motors 13 are in each instance supported on a pivot arm 14 arranged in turn on a pivot shaft 15. In each instance, the pivot arms 15 of the centering rollers 11 that are opposite each other are connected to each other through crank arms 16 and a common arm 17. A pressure operated cylinder 18 drives the centering rollers 11 that are so connected and opposite to each other to opposing adjusting movements symmetrically to the centre feed line 12 (Figure 6).
.../8 1.28~291 A control system (now shown herein) receives a signal that indicates the position of the start and the end of the trunk. This signal can, for example, be sent from a plurality of light barriers (not shown herein) arranged alson the path followed by the tree trunks. In place of this, it is also possible to determine the positions of the start and the end of the tree trunk by computer, once the initial position of the tree trunk 3 has been determined.
The control system controls the cylinder 18 for the positioning movement of the centering rollers in such a manner that each centering roller 11 of the group 5 to 10 that i8 located at the start and the end of the trunk is moved into position, whereas the remaining centering rollers 11 are in the position in which they are withdrawn and not on contact with the tree trunk.
Thus, one can see that in Figure 2 the centering rollrs 11 of group 8 are in position on the start of the tree trunk. In addition, the centering rollers of group 10 are still in position; they are guiding the end of the preceding trunk. The centering rollers of group 5 are still positioned because they are taking over the tree trunk 3 from the chain bed 2.
In the position that is shown in Figure 2, the tree trunk 3 is between the centering rollers 11 of the forward group 10 at the start of the tree trunk and between the centering rollers 11 of the rearmost group 5 at the end of the trunk. In this position, the tree trunk moves into a . . ./9 1 ~85291 _9_ processing station 19, within which a plurality of milling heads 20 that are located opposite each other mill opposing guide surfaces 21 on the tree trunk 3 (Figure 4).
Immediately after passing through the milling heads 20 these guide surfaces 21 are supported and guided on the guide bodies 22.
Immediately after this, the tree trunk 3 enters a processing machine 23 which, in the embodiment shown incorporates a group of circular saws 24, by means of which the tree trunk is cut intD;square timbers or boards. Whilst the tree trunk is moving through the processing machine 23, immediately prior to this it is guided by the guide bodies 22 and at its trunk end by the centering rollers that are positioned there.
The milling heads 20 can be so arranged and designed that they mill four lengthwise edges on the tree trunk 3, these serving as guide surfaces for the subsequent guide bodies 22 and at the same time form the edges of the side boards in the subseguent sawing process.
As can be seen from the drawing, the tree trunk 3 is moved into position root-end first. The top end that forms the rear end of the trunk is, in most cases, straight, whereas the root end is very often curved on one side.
Thus, the tree trunk 3 is centred at the straight top end, while the preceding root end has had its sides milled by the milling heads 20 at the start of the feed process.
. . .~1 .... - : . ~ , , - ., .-; .. -., - , . -:
~.~85291.
The guide bodies 22 can be replaced by guide rollers if the forces that are generated by the subsequent processing machinery are almost balanced out. In the case of greater processing forces that act on one side, the guide bodies 22 are more suitable for guidance and for providing lateral support.
In the description of the embodiment it was stated that the centering rollers 11 that carry out no guiding function for the tree trunk 3 are withdrawn. In place of this, it can be arranged that these centering rollers are only unloaded; the centering rollers then still rest on the tree trunk 3, although they exert no significant lateral forces on the tree trunk and for this reason fulfill no guiding function.
In place of the arrangement shown for the present embodiment, of four centering rollers 11 in each of the groups 5 to 10, another number of centering rollers 11 can be selected, for example, three centering rollers 11 spaced at equal intervals about the periphery of the tree trunk.
It is also possible to provide for centering in one plane only, preferably in the horizontal plane, there being in each group 5 to 10 only two opposing centering rollers 11, while the tree trunk 3 lies and is transported on a roller bed, a chain bed, or on a similar horizontal guide surface.
. . ./11
Tree trunks that are to be processed into beams, s~uare lumber, boards and, in some cases, into usable chips and shavings, in processing machinery such as sawmills and shaping machinery, must be fed into said processing machinery in a straight line, such that the centre line of the feed path coincides precisely with the centre line of the tree trunk, so as to permit optimum utilization of the wood. Any oscillation of the tree trunk has to be prevented as far as possible, for otherwise the cuts are not made in an accurate, straight line.
In order to permit such precise, rectilinear feeding of tree trunks into a processing machine, it is known that guide surfaces can first be milled on the tree trunk; these guide surfaces are rectilinear and make it possible to guide the tree trunk in a straight line along such surfaces as it is being fed into the machinery. This means that the difficulties that result from using the conical and usually curved shape of the outer surface of the tree trunks as guide surfaces can be overcome in the immediate vicinity of the processing machinery; in actual fact, this difficulties are only set aside, for the tree trunk must be guided in a straight line in alignment with the centre axis of the tree trunk in order to mill the guide surfaces.
In a known process (DE-PS 29 21 458), in order that this can be done the tree trunks are picked up in the central area and at the ends by centrally positionable grippers, each of which is supported on a slide that can be moved along a rail. The tree trunks that have been so picked up are moved to milling machines that mill the processing surfaces on which the tree trunks are then guided by means of guide rollers. As soon as the start of the tree trunk i8 picked up by these rollers, the centre gripper opens; the tree trunk is then guided between the guide rollers and the rear gripper. The trunk that is so guided and partially processed is passed to a processing system in which the tree trunk is milled to a cylindrical shape.
There is a further support on this cylindrical surface, while the tree trunk, processed on all sides, is passed to a plurality of feed rollers that are arranged at the input to a subsequent processing machine, such as a saw, for example.
The installation required for this known process is relatively complex. The slides that bear the grippers and which can be moved along the rails have to be returned to their starting positions once a tree trunk has passed and then be loaded before they can move the next tree trunk into the system. This means that that very close limits are i285~91 imposed on the operating rates that can be achieved. Using the known process, in order to permit precise guidance of the tree trunk at the intake of the processing machinery two guide surfaces must be milled on one after the other in two processing stages, which is to say, one for the initial guidance of the start of the trunk, and the other to achieve the cylindrical outer surface prior to entering the group of guide rollers at the start of the processing machinery.
For this reason, it is the task of the present invention to create a process of the type described in the introduction hereto and which permits a rapid operating cycle and precise feeding of the tree trunks into a processing machine at very little cost and in a labour-saving manner.
In addtion, the present invention is intended to create an apparatus that is suitable for carrying out the aforesaid process.
According to the present invention, this task has been solved in tht a plurality of groups of centering rollers--at least some of which can be driven--arranged sequentially in the direction in which the tree trunks are moved are so controlled when a tree trunk is fed in that the centering rollers of the groups through which the start and the end of the trunk is moving are adjusted symmetrically, whereas the centering rollers of the remaining groups remain in their withdrawn or unloaded position, respectively.
~.28529~
In contrast to the grippers that move with the tree trunk, in the process according to the present invention the individual groups of centering rollers remain fixed in place. The only locations that move forward with the tree trunk are those at which the centering rollers support the tree trunk symmetrically to its centre line. This support is effective at the ends of the tree trunk during the whole of the feed process, i.e., all the groups of centering rollers through which the end of the trunk moves in sequence guide and support the end of the trunk. The front of the trunk is supported and guided by the group of centering rollers through which it is passing only until it is introduced into the machine that mills on the guide surfaces, which are then supported immediately afterwards by the guide elements.
In this feed movement the tree trunk can be fed to the processing machinery, for example, a saw, immediately afterwards, without any need to support it between guide rollers. The whole operating cycle can be continuous, for the start of a subsequent trunk can abut directly on the end of a preceding trunk. This permits very high operating speeds.
It is known that in order to feed tree trunks to processing machinery, centering rollers that can be positioned centrally from opposite sides (DE-OS 16 28 866).
Here, however, the centering rollers are arranged in two ` 128S~L
fixed groups through which the trunk moves. If the trunk is curved, it will oscillate.
It is also known to use a roller bed in feed systems for wood processing machinery, said bed supporting the tree trunk (DE-OS 32 46 969). Here, however, the tree trunk is guided along its lower surface line, so that in general it is impossible to align lt centrally with the centre feed line of the processing machinery.
According to a broad aspect of the invention there is provlded, in a process of feeding tree trunks to a processing machlne, the process including the step of cutting guide surfaces into the tree trunk at a cutting station disposed upstream of the processing machlne whereafter the guide surfaces are engaged and supported by guide elements disposed between the cutting station and the processing machine, the improvement comprising centering the tree trunk along a centering line of the processing machine during the delivery of a tree trunk to the cutting station by the steps of:
providing groups of centering rolls upstream of said cutting station, said groups being spaced along said centering line, centering rolls of each said group being adjustable symmetrically between trunk centering and trunk non-centering modes, at least some of said centering rolls being driven to advance a tree trunk, and advancing the tree trunk along said centering line successively through said groups of centering rolls while successively adjusting said groups between their centering ar;d 6a non-centering modes such that groups thereof located to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group disposed therebetween is in a non-centering mode.
According to another broad aspect of the invention there is provided apparatus for processing tree trunks comprising a processing machine defining a centering line, cutting means disposed upstream of said processing machine for cutting guide surfaces into a tree trunk, guide elements disposed between said cuttlng means and said processing machine for engaging and supporting the guide surfaces durlng travel of a tree trunk to said processing machine, the improvement comprising centering means for centering a tree trunk along said centering line during the delivery of the tree trunk to said cutting means, said centering means comprising:
groups of centering rolls disposed upstream of said cutting means, said groups being spaced along said centering line, centering rolls of each sald group being adjustable symmetrically between trunk centerlng and trunk non-centering modes, means for driving at least some of said centerlng rolls for advancing a tree trunk successively through said groups of centering rolls, and means for successively adjusting said groups between thelr centerlng and non-centering modes such that groups ~: thereof arranged to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group : disposed therebetween is in a non-centering mode.
B
` ~ ~85291 6b An advantageous systeln ~or carrying out the process is described in greater detail below on the basis of the drawings appended hereto. These drawings are as follows:
Figure 1: A side view of an apparatus for feeding tree trunks to a saw;
Figures 2 to 4: The apparatus as in Figure 1, in sequential steps of the feed process;
Figure 5, An enlarged partial cross-section on the line V-V in Figure 4;
Figure 6: A partial view in the direction indicated by the arrow VI in Figure 5.
The feed apparatus shown in the drawings has a chain bed 2 ~hat can be raised by means of the parallel arms 1 and can 1.28529~
be driven, the tree trunk 3 that is to be processed is moved on this chain bed 2. Above the exit end of the chain bed 2 there is a follower roller 4 that is so arranged that it can move vertically; this roller is connected to a measuring system (not shown herein). As soon as a tree trunk 3 lies in the position on the chain bed 2 that is shown in Figure 1 it is raised until a signal that is emitted from the follower roller 4 indicates that the centre of the tree trunk 2 is close to the centre feed line. The chain bed 2 is fixed at this level, while the tree trunk 3 is moved ahead. As is shown in Figure 2, the tree trunk 3 passes through a plurality of groups 5 - 10 of centering rollers 11 arranged in sequence one after the other, each of which can be arranged symmterically to the centre feed line 12.
Figure 5 shows that each group 5 - 10 of centering rollers 11 is has two centering roller 11 pairs that are opposite. The centering rollers 11 that can be driven individually from the drive motors 13 are in each instance supported on a pivot arm 14 arranged in turn on a pivot shaft 15. In each instance, the pivot arms 15 of the centering rollers 11 that are opposite each other are connected to each other through crank arms 16 and a common arm 17. A pressure operated cylinder 18 drives the centering rollers 11 that are so connected and opposite to each other to opposing adjusting movements symmetrically to the centre feed line 12 (Figure 6).
.../8 1.28~291 A control system (now shown herein) receives a signal that indicates the position of the start and the end of the trunk. This signal can, for example, be sent from a plurality of light barriers (not shown herein) arranged alson the path followed by the tree trunks. In place of this, it is also possible to determine the positions of the start and the end of the tree trunk by computer, once the initial position of the tree trunk 3 has been determined.
The control system controls the cylinder 18 for the positioning movement of the centering rollers in such a manner that each centering roller 11 of the group 5 to 10 that i8 located at the start and the end of the trunk is moved into position, whereas the remaining centering rollers 11 are in the position in which they are withdrawn and not on contact with the tree trunk.
Thus, one can see that in Figure 2 the centering rollrs 11 of group 8 are in position on the start of the tree trunk. In addition, the centering rollers of group 10 are still in position; they are guiding the end of the preceding trunk. The centering rollers of group 5 are still positioned because they are taking over the tree trunk 3 from the chain bed 2.
In the position that is shown in Figure 2, the tree trunk 3 is between the centering rollers 11 of the forward group 10 at the start of the tree trunk and between the centering rollers 11 of the rearmost group 5 at the end of the trunk. In this position, the tree trunk moves into a . . ./9 1 ~85291 _9_ processing station 19, within which a plurality of milling heads 20 that are located opposite each other mill opposing guide surfaces 21 on the tree trunk 3 (Figure 4).
Immediately after passing through the milling heads 20 these guide surfaces 21 are supported and guided on the guide bodies 22.
Immediately after this, the tree trunk 3 enters a processing machine 23 which, in the embodiment shown incorporates a group of circular saws 24, by means of which the tree trunk is cut intD;square timbers or boards. Whilst the tree trunk is moving through the processing machine 23, immediately prior to this it is guided by the guide bodies 22 and at its trunk end by the centering rollers that are positioned there.
The milling heads 20 can be so arranged and designed that they mill four lengthwise edges on the tree trunk 3, these serving as guide surfaces for the subsequent guide bodies 22 and at the same time form the edges of the side boards in the subseguent sawing process.
As can be seen from the drawing, the tree trunk 3 is moved into position root-end first. The top end that forms the rear end of the trunk is, in most cases, straight, whereas the root end is very often curved on one side.
Thus, the tree trunk 3 is centred at the straight top end, while the preceding root end has had its sides milled by the milling heads 20 at the start of the feed process.
. . .~1 .... - : . ~ , , - ., .-; .. -., - , . -:
~.~85291.
The guide bodies 22 can be replaced by guide rollers if the forces that are generated by the subsequent processing machinery are almost balanced out. In the case of greater processing forces that act on one side, the guide bodies 22 are more suitable for guidance and for providing lateral support.
In the description of the embodiment it was stated that the centering rollers 11 that carry out no guiding function for the tree trunk 3 are withdrawn. In place of this, it can be arranged that these centering rollers are only unloaded; the centering rollers then still rest on the tree trunk 3, although they exert no significant lateral forces on the tree trunk and for this reason fulfill no guiding function.
In place of the arrangement shown for the present embodiment, of four centering rollers 11 in each of the groups 5 to 10, another number of centering rollers 11 can be selected, for example, three centering rollers 11 spaced at equal intervals about the periphery of the tree trunk.
It is also possible to provide for centering in one plane only, preferably in the horizontal plane, there being in each group 5 to 10 only two opposing centering rollers 11, while the tree trunk 3 lies and is transported on a roller bed, a chain bed, or on a similar horizontal guide surface.
. . ./11
Claims (9)
1. In a process of feeding tree trunks to a processing machine, the process including the step of cutting guide surfaces into the tree trunk at a cutting station disposed upstream of the processing machine whereafter the guide surfaces are engaged and supported by guide elements disposed between the cutting station and the processing machine, the improvement comprising centering the tree trunk along a centering line of the processing machine during the delivery of a tree trunk to the cutting station by the steps of:
providing groups of centering rolls upstream of said cutting station, said groups being spaced along said centering line, centering rolls of each said group being adjustable symmetrically between trunk centering an trunk non-centering modes, at least some of said centering rolls being driven to advance a tree trunk, and advancing the tree trunk along said centering line successively through said groups of centering rolls while successively adjusting said groups between their centering and non-centering modes such that groups thereof located to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group disposed therebetween is in a non-centering mode.
providing groups of centering rolls upstream of said cutting station, said groups being spaced along said centering line, centering rolls of each said group being adjustable symmetrically between trunk centering an trunk non-centering modes, at least some of said centering rolls being driven to advance a tree trunk, and advancing the tree trunk along said centering line successively through said groups of centering rolls while successively adjusting said groups between their centering and non-centering modes such that groups thereof located to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group disposed therebetween is in a non-centering mode.
2. A method according to claim 1, wherein said groups are adjusted to their non-centering modes by being displaced out of contact with the tree trunk.
3. A method according to claim 1 including the step of measuring the diameter of a tree trunk before introducing the tree trunk to the groups of centering rolls.
4. A method according to claim 1, wherein a force is applied to said groups for adjusting said groups to their centering modes, said groups being adjusted to their non-centering modes by releasing said force.
5. Apparatus for processing tree trunks comprising a processing machine defining a centering line, cutting means disposed upstream of said processing machine for cutting guide surfaces into a tree trunk, guide elements disposed between said cutting means and said processing machine for engaging and supporting the guide surfaces during travel of a tree trunk to said processing machine, the improvement comprising centering means for centering a tree trunk along said centering line during the delivery of the tree trunk to said cutting means, said centering means comprising:
groups of centering rolls disposed upstream of said cutting means, said groups being spaced along said centering line, centering rolls of each said group being adjustable symmetrically between trunk centering and trunk non-centering modes, means for driving at least some of said centering rolls for advancing a tree trunk successively through said groups of centering rolls, and means for successively adjusting said groups between their centering and non-centering modes such that groups thereof arranged to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group disposed therebetween is in a non-centering mode.
groups of centering rolls disposed upstream of said cutting means, said groups being spaced along said centering line, centering rolls of each said group being adjustable symmetrically between trunk centering and trunk non-centering modes, means for driving at least some of said centering rolls for advancing a tree trunk successively through said groups of centering rolls, and means for successively adjusting said groups between their centering and non-centering modes such that groups thereof arranged to support front and rear ends of the advancing tree trunk are in their centering modes while at least one group disposed therebetween is in a non-centering mode.
6. Apparatus according to claim 5, wherein said rolls of each group of rolls are adjustable away from said centering line to positions out of contact with a tree trunk to define said non-centering mode.
7. Apparatus according to claim 5 including a conveyor disposed upstream of said groups of rolls.
8. Apparatus according to claim 5, wherein said group comprises two pairs of diametrically opposed rolls.
9. Apparatus according to claim 6 including means mechanically interconnecting a plurality of rolls of each group for achieving simultaneous movement thereof toward and away from said centering line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000532683A CA1285291C (en) | 1987-03-23 | 1987-03-23 | Process and an apparatus to feed tree trunks to a processing machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000532683A CA1285291C (en) | 1987-03-23 | 1987-03-23 | Process and an apparatus to feed tree trunks to a processing machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1285291C true CA1285291C (en) | 1991-06-25 |
Family
ID=4135244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000532683A Expired - Lifetime CA1285291C (en) | 1987-03-23 | 1987-03-23 | Process and an apparatus to feed tree trunks to a processing machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1285291C (en) |
-
1987
- 1987-03-23 CA CA000532683A patent/CA1285291C/en not_active Expired - Lifetime
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