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(11) | EP 1 403 015 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Timber working unit |
| (57) The invention relates to a timber working unit for machining crib grooves in the
log and for cutting the log to size, the unit comprising at least two device frames
(1, 2) disposed at a distance from each other, the distance.between which can be adjusted.
The device frame (1) comprises a cutting tool (3) for cutting the log to be worked
and a milling tool (4) for machining a crib groove in the log to be worked (5), as
well as a conveyor chain (6) with its support arrangements for conveying the log to
be worked in the crosswise direction through the manufacturing phases of the device
frames. According to the invention, the support arrangements include in the conveyor
chain (6) a rigid pusher stop (7) for conveying the log to be worked (5) along with
the motion of the conveyor chain; in the machining area of the cutting tool (3) and
milling tool (4), a lower support (8) supporting the log; as well as in the machining
area of the cutting tool and milling tool, a tightening element (9) provided with
elasticity, pressing the log against the lower support. In addition, the machining
directions of the cutting tool and milling tool are arranged to press the log to be
worked'against a space which is open forwards in the direction of motion of the log
and defined by the lower support, pusher stop and tightening element. |
[0001] The invention relates to a timber working unit for machining crib grooves in the logs and for . cutting the logs to size.
[0002] In industrial manufacturing of timber houses the manufacturing of timber is carried out in automated production plants. In these plants the logs are conveyed length-wise into a machining area in which there are a set of various machining units. The logs are stopped at a specific machining unit for sawing, milling, drilling or making the notches, and so, having gone through all the phases in the machining area, the timber element is ready to be erected. Although these procedures are fully automated and thereby extremely accurate and work well, the disadvantage associated with them is their inefficiency. Although the log is cut to size with just one crib groove made at both ends, four different working phases and four stops are needed regardless of the log length before the next log may be conveyed into the machining area.
[0003] The aforementioned problems haven been mainly eliminated by the device as described in the earlier Finnish patent application FI20001234 of the applicant. This wood working unit comprises a frame, at least one machine tool and conveying equipment for conveying the log to be worked onto the machine tool and away from it. The aforementioned conveying equipment comprises a conveyor chain consisting of stiff loops joined together, which uses at least two chain pulleys. In this way, the conveying equipment is able to move the log to be worked substantially in a crosswise direction while the tightening elements of the conveying equipment are tightening the log to be worked relative to the conveyor chain. The tightening elements of the conveyor chain comprise support flanges placed in two different loops of the conveyor chain, which are extended perpendicularly from the conveyor chain in the direction of the radius of the chain pulley. In this way the support flanges rounding the pulley chain spread at an outward angle relative to each other, making it easy to place between them a log to be worked. When the conveyor chain moves on to the straight stretch, the support flanges become parallel and come closer to each other in such a manner that the log to be worked is pressed and tightened between them.
[0004] By using the wood working unit as described above the working of the logs may be carried out as an uninterrupted process, wherein the logs do not need to be moved back and forth or stopped or repeatedly conveyed while working them. Because the logs are constantly in motion throughout the whole process and are moved in a crosswise direction, they move relatively close to each other without taking much space, so that although the logs are moved at a relatively gentle speed, the achieved working pace is increased greatly in comparison with the prior art.
[0005] There are, however, certain disadvantages associated with the prior art, The pressing of the log in between two flanges turning towards each other for the duration of the machining is not sufficient. During the machining, the log tends to shake and thus partially become unfastened, in which case e.g. the measuring accuracy of the corner cribs is not sufficient. In the same manner, there are problems with the possibly necessary turning of the log, i.e. in case there is a wish to machine a part of the crib grooves also on the flanks of the log, the log has to be re-fed, as being turned 90° around its longitudinal axis, into a suitable machining phase. A further problem is associated with the machining of logs of different widths. When the log is pressed tight to the conveyor chain on both flanks thereof with fixed flanges, the flanges must be accurately disposed at a certain distance from each other. In this way, a certain placing of flanges is only suitable for logs with a certain width. However, there is a need for machining logs of different thickness in respect of their width.
[0006] The objective of the invention is to eliminate the drawbacks referred to above. One specific objective of the invention is to disclose an improved timber working unit in which the log is held firmly in place during the machining, in which it can be easily turned into different positions in a constant process when necessary and in which logs having different dimensions can be flexibly machined.
[0007] As for the features characteristic of the invention, reference is made to them in the claims.
[0008] The timber working unit in accordance with the invention for machining crib grooves in a log, either a planed log or a round log, and for cutting the log to size comprises at least two device frames disposed at a distance from each other, the distance between which can be adjusted. The device frames are provided with a cutting tool for cutting the log to be worked and a milling tool for machining a crib groove in the log to be worked, as well as a conveyor chain with its support arrangements for conveying the log to be worked in the crosswise direction through the machining phases of the device frames. According to the invention, the support arrangements include a rigid pusher stop in the conveyor chain for conveying the log to be worked, along with the motion of the conveyor chain, ahead of the pusher stop; in the machining area of the cutting tool and milling tool, a lower support supporting the log; as well as in the machining area of the cutting tool and milling tool, a tightening element provided with elasticity, pressing the log against the lower support. Furthermore, the machining directions of the cutting tool and milling tool are arranged to press the log being worked towards a space defined by the lower support, pusher stop and tightening element. Thus, in the timber working unit in accordance with then invention, the log is firmly pressed, i.e. firmly tightened, in the vertical direction in the space between the lower support and the upper support while the pusher stop pushes the log ahead of itself between these supports. In this space, which is forwards open, allowing the machining of logs of different thickness, the machining of the crib grooves is performed with suitable blades.
[0009] Advantageously, the conveyor chain includes several successive pusher stops. The pusher stops are preferably straight and rigid pegs or plates which are disposed at right angles relative to the conveyor chain.
[0010] Advantageously, the tightening element includes an adjustment element for adjusting the distance between the tightening element and the lower support according to the height of the log being worked. In this manner, in the rest position, the tightening element is clearly closer to the lower support than is the height of the log being worked.
[0011] Advantageously, the tightening element includes a throat oblique relative to the path of motion of the log, i.e. a surface extending obliquely downward, which, while being pushed by the pusher stop of the log, forces the log into pressure in between the lower support and tightening element, i.e. in practice lifts the tightening element upward while the log moves in between the lower support and the tightening element.
[0012] Advantageously, after the milling tool, the path of motion of the log includes a turning stop for turning the log 90° around its longitudinal axis, after which the unit includes a second milling tool with its lower supports and tightening elements for machining the crib grooves on the flanks of the log. Thus, in a successive process, the whole log, both ends thereof and all the surfaces can be completely machined.
[0013] As the turning stop, a fixed support can be used, and the log turns when colliding with it, but in that case the turning is inaccurate, and the. log can be forced into an oblique angle. Due to this, as the turning stop, a turning wheel consisting of four sectors of 90 degrees is preferably used, which as being freely rotating, is arranged in the path of motion of the log, preferably at both ends thereof. The wheel evenly turns the log 90 degrees while being pushed by the pusher stops.
[0014] In one embodiment of the invention, the timber working unit comprises, as an extension of the horizontal machining path of motion, a drilling tool which can have one or more blades. Since the log proceeds forward in its machining path of motion in an open space, the drilling tool, whose blades are disposed in the direction of the path of motion of the log, can be used to drill a necessary number of holes in the log, at desired points.
[0015] Considerable advantages are associated with the timber working unit in accordance with the invention as compared to the prior art. In the working unit in accordance with the invention, the log is held firmly in place throughout the whole working process. It is possible to accurately handle each flank of the timber. Furthermore, changes in the width of the log do not cause a need for changes in the conveying and support arrangements of the log but just the change of blades, which makes the invention considerably more versatile and fast as compared to the prior art.
[0016] In the following section, the invention will be described in detail with reference to the accompanying drawings, in which
Fig. 1 schematically represents one timber working unit in accordance with the invention as seen from the side,
Fig. 2 represents the unit of Fig. 1 as seen from the front; and
Fig. 3 represents one turning stop in accordance with the invention.
[0017] The timber working unit as shown in Figs. 1 and 2 comprises two device frames 1 and 2, the one of which is a fixed one, while the other one can be moved in such a way that the distance between the device frames is adjustable in the length-wise direction of the log 5. Both device frames 1 and 2 are provided with two machine tools, i.e. a cutting tool 3 and a milling tool 4. The cutting tool consists of a circular saw blade which is suitably disposed in the path of motion of the log for cutting the log or for trimming the end thereof. The milling tool comprises a top blade 13 and a bottom blade 14 operated by a suitable power unit for simultaneously milling the log 5 to be worked on the opposite sides, i.e. for machining a crib groove in the log.
[0018] Supported on the device frame 1 are two conveyor chains 6, and supported on the device frame 2 is one conveyor chain 6, which are arranged to be rotatable by means of a suitable power unit hinged on the chain pulleys 15. The chain pulleys of the one end are connected to the power unit and to one another by means of a cross-over shaft 16, which allows one to move the second device frame 2 to a distance from the first device frame 1.
[0019] The support arrangement by which the log to be worked is supported on the equipment is as follows. The conveyor chains to be used 6 consist of stiff loops joined together. Attached to the loops of the conveyor chain are several pusher stops 7, i.e. rigid supports or pegs disposed, at uniform intervals from one another, which are at right angles relative to the path of motion of the conveyor chain and push ahead of themselves the log 5 disposed on top of the conveyor chain 6. In the machining area of the cutting tool 3 and milling tool 4 there is a horizontal lower support 8 disposed in the direction of the conveyor chain, on top of which and supported on which the log is in motion during the working process. Furthermore, in the aforementioned machining area there is a tightening element 9 disposed on top of the log, which during the machining strongly presses the log towards the lower support. In this way, during the machining, while being pushed by the pusher stop, the log moves on top of the lower support while the tightening element strongly presses the log against the lower support. Furthermore, the machining blades of the machining area, i.e. the circular saw blade of the cutting tool 3 and the upper blade 13 and lower blade 14 of the milling tool 4 are arranged to rotate in such a manner that their machining directions to the log are opposite relative to the path of motion of the log. Thus, the log to be worked is during the machining in an upward, downward and backward closed machining space and only forward in an open machining space . In this way, the machining blades press the log being worked more firmly than before into the gap formed by the pusher stop 7, lower support 8 and tightening element 9.
[0020] The tightening element 9 consists of a shoe 17 disposed in the direction of the lower support 8, the front edge of the shoe 17 turning upward, forming a throat 11, into which the pusher stop 7 pushes the log. By means of a flexible spring structure, the shoe is supported on the frame of the device. Furthermore, the basic height of the shoe can be changed by an adjustment element 10 according to the height of the log being worked in such a manner that in a rest position, the shoe is always considerably lower than the upper surface of the log being worked.
[0021] As can be seen from Fig. 1, after the first machining phase, there is a turning stop 12 arranged in the path of motion of the conveyor chain 6, and the log turns on its side as it collides with the turning stop. After this there is a second corresponding machining phase in which suitable crib grooves are machined on the flanks of the log by pressing and holding the log in place during the machining.
[0022] In the device frame 1 of Fig. 2 there are two conveyor chains 6, and the milling tool is disposed between them because this enables one to machine also very short logs, of which e.g. corner posts are made. This enables one to use in the device a cutting tool 3 on both sides thereof at the same distance from the milling tool, or on the one side it is possible to use a suitable limiter or stop, against which the end of the log is pushed as the cutting tool cuts the log to a suitable size. In manufacturing longer logs, in practice in manufacturing logs of 1.5 meters, the device frame 2 can be placed at a suitable distance from the device frame 1 as the cutting tools disposed in the far edges cut the log to a suitable size.
[0023] Fig. 3 schematically represents a device corresponding to Fig. 1, in the which the difference is the structure of the turning stop 12. In Fig. 1, as the turning stop there is just a fixed obstacle which is arranged in the path of motion of the log 5 for turning it 90 degrees around its longitudinal axis. In the embodiment of Fig. 3 there is a more advanced solution in which the turning stop consists of a freely rotating wheel arranged in the path of motion of the log. The wheel has four flanges or bars 18 disposed at uniform intervals, i.e. the sectors of 90 degrees and the wheel shaft are disposed substantially at the level of the conveyor chain. As the log, being conveyed by the pusher stop 7, comes against the flange or bar disposed in an upright position, it starts to turn the flange ahead of itself, causing the flange underneath to rise and lift the log. In this way, while being pushed by the pusher stop, the log rises and turns forward in the sector 90 degrees in a very controlled and smooth manner. Advantageously, each device frame or at least two device frames use freely rotating wheels of this kind.
[0024] The forward open space, in which the log is held firmly in place during the machining, has the advantage that by arranging on the front side of the horizontal path of motion of the log a drilling tool 19 moving in the horizontal direction, it is possible to drill in the log e.g. dowelling holes and electrification holes with no need to make the drilling a separate working phase. This is also a significant advantage from the standpoint of the machining speed and the ease of machining. The drilling tool 19 may have even several blades side by side in the longitudinal direction of the log, so that just one push by the drilling tool is needed and all the necessary holes are made. The drilling can be carried out while the log is in normal motion in such a manner that the log need not be stopped while the holes are being drilled. In this way, the forward open space enables the drilling of the log without no need to increase the working time.
1. A timber working unit for machining crib grooves in the log and cutting the log to
size, the unit comprising at least two'device frames (1, 2) disposed at a distance
from each other, the distance of which can be adjusted, the device frame (1) comprising
a cutting tool (3) for cutting the log to be worked and a milling tool (4) for machining
a crib groove in the log to be worked (5) , as well as a conveyor chain (6) with its
support arrangements for conveying the log to be worked in the crosswise direction
through the machining phases of the device frames,
characterised in that the support arrangements comprise
characterised in that the support arrangements comprise
- in the conveyor chain (6), a rigid pusher stop (7) for conveying the log to be worked (5) along with the motion of the conveyor chain,
- in the machining area of the cutting tool (3) and milling tool (4), a lower support (8) supporting the log,
- in the machining area of the cutting tool and milling tool, a tightening element (9) provided with elasticity, pressing the log against the lower support, and
- that the machining directions of the cutting 'tool and the milling tool are arranged to press the log to be worked against a space which is forwards open in the direction of motion of the log and defined by the lower support, pusher stop and tightening element.
2. The timber working unit according to claim 1, characterised in that the conveyor chain (6) comprises several successive pusher stops (7).
3. The timber working unit according to claim 1, characterised in that the pusher stop (7) consists of a peg perpendicular to the path of motion of the
conveyor chain (6).
4. The timber working unit according to claim 1, characterised in that the tightening element (9) comprises an adjustment element (10) for adjusting the
distance between the tightening element and the lower support (8) according to the
height of the log to be worked.
5. The timber working unit according to claim 1, characterised in that the tightening element (9) comprises a throat (11) oblique with respect to the direction
of motion of the log for conveying the log in between the lower support and the tightening
element while the pusher stop keeps pushing.
6. The timber working unit according to claim 1, characterised in that after the milling tool there is in the path of motion of the log a turning stop (12)
for turning the log 90° around its longitudinal axis, after which there is in the
unit a second milling tool with its lower supports and flexible upper supports for
machining crib grooves' on the flanks of the log.
7. The timber working unit according to claim 6, characterised in that the turning stop consists of a freely rotating wheel consisting of four sectors of
90 degrees.
8. The timber working unit according to any one of claims 1-7, characterised in that the timber working unit comprises, as an extension to the horizontal working path
of motion of the log, a drilling tool (19) for drilling holes in the log during the
horizontal crosswise motion of the log.