Method and Device for Automatic Packing of Wood

Abstract

A method of preparing wood for packing comprises: loading wood lengthwise into a conveyor system; conveying the wood pieces one-by-one onto a loading hatch in a predetermined orientation; when a wood piece is fully on the loading hatch, opening the loading hatch and dropping the wood piece in the predetermined orientation into a measuring compartment; repeating the conveying and dropping process so that multiple wood pieces are stacked in the same orientation in the measuring compartment; and, when a required amount of stacked wood is within the measuring compartment, dropping the stacked wood pieces into a packing area.

Claims

1. A method of preparing wood for packing, wherein the wood consists of wood pieces having a length and a cross-section with smaller dimensions than the length, the method comprising: loading wood lengthwise into a conveyor system; conveying the wood pieces one-by-one onto a loading hatch in a predetermined orientation; when a wood piece is fully on the loading hatch, opening the loading hatch and dropping the wood piece in the predetermined orientation into a measuring compartment; repeating the conveying and dropping process so that multiple wood pieces are stacked in the same orientation in the measuring compartment; and, when a required amount of stacked wood is within the measuring compartment, dropping the stacked wood pieces into a packing area.

2. A method as claimed in claim 1, including determining when the required amount of wood pieces is stacked in the measuring compartment by using one or more sensors.

3. A method as claimed in claim 1 or 2, including sliding the wood pieces lengthwise along a channel to load the conveyor system, wherein the channel is shaped to guide the wood pieces and prevent them from leaving the lengthwise orientation.

4. A method as claimed in claim 3, wherein the channel is a downwardly sloping V-shaped channel.

5. A method as claimed in claim 3 or 4, wherein the channel is a V shaped conveyor channel wherein one wall of the V is a static wall and the other wall of the V is a conveyor wall.

6. A method as claimed in claim 3 or 4, wherein the channel has a first downwardly sloped section, followed by flatter, less sloped section, and then followed by a second downwardly sloped section.

7. A method as claimed in any preceding claim, comprising using the conveyor system for maintaining a lengthwise alignment of the wood pieces and for separating the wood pieces from one another so that there is a gap between the trailing end of a first wood piece and the leading end of a second wood piece.

8. A method as claimed in claim 7, comprising conveying wood pieces with a relatively small spacing on a first, loading, conveyor operating at a first speed, and transferring the wood pieces onto a second, separating, conveyor operating at a second, higher, speed, such that the wood pieces have an increased spacing on the second conveyor compared to on the first conveyor.

9. A method as claimed in claim 7 or 8, comprising using a or the downwardly sloping channel to load wood pieces one-by-one onto a conveyor that is slanted at an upward angle in the direction of travel.

10. A method as claimed in claim 7, 8 or 9, comprising using a or the downward sloping channel to load a first, loading, conveyor, and then passing the wood pieces from the loading conveyor to a second, separating conveyor that is operated at a higher speed than the loading conveyor in order to increase the spacing between the wood pieces.

11. A method as claimed in any preceding claim, including using a buffer compartment beneath the loading hatch and above the measuring compartment, wherein the buffer compartment provides a buffer for temporary storage of any wood pieces that are passed along the conveyor system and through the loading hatch after the required quantity of wood is stacked in the measuring compartment.

12. A method as claimed in claim 11, comprising closing a buffer compartment hatch when the measuring compartment has been filled with the required amount of wood, and then opening the buffer compartment hatch when the measuring compartment has been emptied and is ready for the next batch.

13. A method as claimed in any preceding claim, wherein the predetermined orientation for the wood piece relative to the loading hatch is a lengthwise orientation such that a door of the loading hatch opens along a hinge that is generally parallel with the length of the wood piece.

14. A method as claimed in any preceding claim, wherein the loading hatch has a door comprising two flaps opening in a V-shape.

15. A method as claimed in any preceding claim, including using a waste extraction machine to receive the wood pieces from a hopper, to remove waste material, and to load the wood pieces onto the conveyor system, wherein the waste extraction machine is also used to provide a preliminary separation of the wood pieces to allow them to be loaded in a lengthwise orientation without risk of jamming.

16. A method as claimed in claim 15, wherein the waste extraction machine comprises a conveyor with voids along the conveyor for waste material to fall through, and wherein the method includes agitating the wood pieces as they travel along the conveyor of the waste extraction machine.

17. A method as claimed in claim 15 or 16, wherein the waste extraction machine uses non-circular rotors spaced apart along a sequence of axles, where the rotors rotate to propel the wood pieces along the machine from axle to axle, and also act to bounce the wood pieces up and down due to their non-circular shape.

18. A method as claimed in claim 15, 16 or 17, wherein the waste extraction machine uses rotors spaced apart along a sequence of axles and the speed of rotation of the axles is increased for axles further along in the direction of travel compared to the speed of rotation of axles further back in the direction of travel.

19. An apparatus for preparing wood for packing, wherein the wood consists of wood pieces having a length and a cross-section with smaller dimensions than the length, the apparatus comprising: a loading mechanism for loading wood lengthwise onto a conveyor system; a hatch for receiving wood pieces one-by-one from the conveyor system; and a measuring compartment for receiving wood pieces dropped through the hatch; wherein the conveyor system is for conveying the wood pieces one-by-one onto the loading hatch in a predetermined orientation; wherein the apparatus is arranged so that when a wood piece is fully on the loading hatch, then the loading hatch is opened and drops the wood piece in the predetermined orientation into the measuring compartment; such that the measuring compartment can be filled with multiple wood pieces stacked in the same orientation when the conveying and dropping process is repeated; and wherein the measuring compartment is operable so that, when a required amount of wood is stacked within the measuring compartment, the stacked wood pieces are dropped into a packing area.

20. An apparatus as claimed in claim 19, comprising a channel for lengthwise sliding of the wood pieces to load the conveyor system, wherein the channel is shaped to guide the wood pieces and prevent them from leaving the lengthwise orientation.

21. An apparatus as claimed in claim 20, wherein the channel is downwardly sloping V-shaped channel.

22. An apparatus as claimed in 20 or 21, wherein the channel is a V shaped conveyor channel wherein one wall of the V is a static wall and the other wall of the V is a conveyor wall.

23. An apparatus as claimed in claim 20 or 32, wherein the channel has a first downwardly sloped section, followed by flatter, less sloped section, and then followed by a second downwardly sloped section.

24. An apparatus as claimed in any of claims 19 to 23, wherein the conveyor system is arranged for maintaining a lengthwise alignment of the wood pieces and for separating the wood pieces from one another so that there is a gap between the trailing end of a first wood piece and the leading end of a second wood piece.

25. An apparatus as claimed in claim 23, wherein the conveyor system includes a first, loading conveyor operating at a first speed, with a second separating conveyor operating at a second speed, the second speed being higher than the first speed.

26. An apparatus as claimed in any of claims 19 to 25, wherein a or the downwardly sloping channel is provided for loading the conveyor system, wherein the wood pieces are slid along the channel and wherein the conveyor system begins with a conveyor that is slanted at an upward angle in the direction of travel.

27. An apparatus as claimed in any of claims 19 to 25, wherein a or the downward channel is provided for loading lengthwise wood pieces onto a first, loading, conveyor, wherein the loading conveyor is for passing the wood pieces to a second, separating conveyor in order to increase the spacing, and wherein the separating conveyor operates at a higher speed than the loading conveyor.

28. An apparatus as claimed in any of claims 19 to 27, including a buffer compartment beneath the loading hatch and above the measuring compartment, wherein the buffer compartment is for temporary storage of any wood pieces that are passed along the conveyor system and through the loading hatch after the required quantity of wood is stacked in the measuring compartment.

29. An apparatus as claimed in claim 28, wherein the apparatus is arranged so that the buffer compartment stores wood pieces when the measuring compartment has been filled with the required amount of wood, and releases the stored wood pieces from the buffer compartment into the measuring compartment once the measuring compartment has emptied the previous batch of stacked wood pieces into the packaging area.

30. An apparatus as claimed in claim 28 or 29, wherein the buffer compartment includes a hatch for opening and closing the compartment and the apparatus is arranged to close the buffer compartment hatch when the measuring compartment has been filled with the required amount of wood, and then to open the buffer compartment hatch when the measuring compartment has been emptied and is ready for the next batch.

31. An apparatus as claimed in any of claims 19 to 30 wherein the predetermined orientation of the wood pieces is a lengthwise orientation such that a door of the loading hatch opens along a hinge that is generally parallel with the length of the wood piece.

32. An apparatus as claimed in any of claims 19 to 31, wherein the loading hatch has a door comprising two flaps opening in a V-shape.

33. An apparatus as claimed in any of claims 19 to 32, comprising a waste extraction machine for removing waste from the wood pieces before they are loaded onto the conveyor system, and a hopper for supplying wood to the waste extraction machine; wherein the waste extraction machine is for supplying wood pieces to the conveyor system, and wherein the waste extraction machine is arranged to provide a preliminary separation of the wood pieces to allow them to be loaded in a lengthwise orientation without risk of jamming.

34. An apparatus as claimed in claim 33, wherein the waste extraction machine comprises a conveyor with voids along the conveyor for waste material to fall through, wherein the conveyor is arranged to agitate the wood pieces as they travel along it.

35. An apparatus as claimed in claim 33 or 34, wherein the waste extraction machine comprises non-circular rotors spaced apart along a sequence of axles, and wherein the rotors rotate to propel the wood pieces along the machine from axle to axle, and also act to bounce the wood pieces up and down due to the non-circular shape.

36. An apparatus as claimed in claim 33, 34 or 35, wherein the waste extraction machine comprises rotors spaced apart along a sequence of axles and the axles further along in the direction of travel rotate more quickly than the axles further back in the direction of travel.

37. An apparatus for preparing wood for packing substantially as hereinbefore described with reference to FIGS. 1 to 3, FIG. 4 or FIGS. 5 and 6 of the accompanying drawings.

38. A method for preparing wood for packing substantially as hereinbefore described.

Description

[0042] Certain preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

[0043] FIG. 1 shows an example apparatus for automatically preparing a bundle of wood for packing;

[0044] FIG. 2 is a diagram illustrating the arrangement of a waste extraction/wood cleaning machine used with the apparatus of FIG. 1;

[0045] FIG. 3 shows the interaction of the downward channel and the upward conveyor in the apparatus of FIG. 1;

[0046] FIG. 4 shows another example apparatus for automatically preparing a bundle of wood for packing;

[0047] FIG. 5 is a perspective view of a V shaped conveyor channel that may be used in place of the V shaped channel in the FIG. 1 apparatus or the FIG. 4 apparatus; and

[0048] FIG. 6 is a view of the V shaped conveyor channel of FIG. 5 shown end on.

[0049] The wood packing apparatus is shown in elevation in FIG. 1. The wood in an example consists of split logs of roughly the same length, as typically provided for use as firewood intended for domestic wood burners and the like. It will be appreciated that the cross-sectional shape and size of the split logs can vary greatly. The wood packing apparatus is designed to allow for variation in cross-section whilst packing the wood efficiently into a defined volume. The apparatus works most effectively if all of the wood pieces are the same length. The apparatus can however cope with variations in length within the same batch of wood. The apparatus can also be arranged to have an adjustable mechanism so that to can handle batches of wood with larger or smaller maximum lengths of the wood. The wood will in general be roughly prismatic, although as it is a natural product then the shape will not be perfectly regular in a geometric shape. References below to the length of the wood pieces and to a lengthwise orientation are a reference to the longest dimension of the wood piece and to wood pieces aligned along the direction of this longest dimension. In general this will be the length of a roughly prismatic shape, which in the case of a split log will often be a prism with a cross-section that is roughly a sector of a circle.

[0050] The wood is supplied to the apparatus via a channel/slide/conveyor 1 or similar, which feeds logs into the waste extraction/wood cleaning machine 2. The waste extraction/wood cleaning machine 2 is for separating waste material, such as bark, dirt and wood chips, from the wood pieces. The waste extraction/wood cleaning machine 2 comprises of a sequence of axles 16 with rotors 17 that propel the wood pieces along whilst also agitating them with an up-and-down motion. FIG. 2 shows an example arrangement. The axles 16 are aligned generally horizontally and hence form a roughly horizontal surface along which the wood pieces are moved. This is in the direction of the arrows X in FIG. 2. The rotors 17 have an irregular (non-circular) shape, which in this example is an octagonal shape. Loose material that is attached to the logs is shaken off by the up and down motion. There are gaps between the rotors allowing the loose material to fall though the rotors 17 and axles 16 in the direction Y in FIG. 2 and into a container 3, which is beneath the waste extraction/wood cleaning machine 2 as shown in FIG. 1. The collected loose material, which might be predominately bark and small wood pieces, may be discarded or recycled. The rotors 17 in a preferred arrangement take the form of plates with irregular diameter, for example rotating octagonal plates as shown or alternatively hexagonal plates. The shape of the rotors 17 is not particularly limited but it may be an advantage to have sharp external corners, to help propel the wood pieces along, and it is also preferred to avoid internal curves or corners, since this can create a risk of jams. Circular rotors could be used and these would minimise the risk of jams. However, circular rotors will not generate such a large up-and-down motion for the wood and hence may not so effectively remove waste material.

[0051] In the preferred arrangement the wood pieces are aligned lengthwise across the axles, so that the axles are perpendicular to the length of the wood pieces and the wood pieces are transported along the length direction. It is also preferred for the rotational speed of the rotors to increase in the direction of travel. This can aid by increasing the separation of the wood pieces.

[0052] Referring again to FIG. 1, the waste extraction/wood cleaning machine 2 transports the wood pieces to a channel 4, where they are aligned lengthwise one-by one. A guide plate may be present to guide the wood pieces from the waste extraction/wood cleaning machine 2 into the channel 4. The channel 4 is angled downwards from the waste extraction/wood cleaning machine 2 so that the logs slide down the channel 4. The cross-section of the channel 4 in a preferred arrangement is a V shape, with the width of the V being considerably less than the length of the wood pieces. This ensures that the wood pieces are correctly aligned. The channel 4 acts both to transport the wood pieces and also as a buffer to ensure that the next part of the apparatus is continually fed with wood. The channel 4 in this Figure allows sliding movement powered only by gravity and by the speed of the wood pieces entering the channel 4 from the waste extraction/wood cleaning machine 2. This channel 4 could however be replaced by a channel 4 using a conveyor mechanism as shown in FIGS. 5 and 6, for example.

[0053] The channel 4 leads to a loading conveyor 5 with sidewalls 6. The conveyor 5 might use a belt or similar. The sidewalls 6, or equivalent rail or guide parts, ensure that the wood pieces remain in the lengthwise orientation whilst they are on the loading conveyor 5. The wood pieces are picked up one-by-one from the bottom of the channel 4 by the loading conveyor 5. Since the channel 4 is angled downward and the loading conveyor 5 is angled upward then the wood pieces are separated from each other as they are picked up by the loading conveyor 5. The separation is illustrated in FIG. 3 in the sequence (A) to (F) with schematic drawings that illustrate how a gap G is formed between consecutive wood pieces. When a first wood piece A is picked up by the conveyor 5 then the following piece B is blocked from contact with the loading conveyor 5 until the first piece A is fully loaded onto the loading conveyor 5 and has moved up the conveyor 5 to clear the height of the next piece B. The following piece B can then slide down the channel 4 and when it is picked up by the loading conveyor 5 there is a gap G between the first piece A and the subsequent piece B. A gap will be formed between all wood pieces in a similar way, since in each case a first piece will block a second piece until the first piece has moved up the conveyor. This gap is useful since it allows for separation of the wood pieces when they are passed to the next stage. With reference again to FIG. 1, the loading conveyor transports the wood pieces one by one up to a separating conveyor 7. Again this conveyor 7 has sidewalls 6 or similar in order to maintain the alignment of the wood pieces. The separating conveyor 7 operates with a greater speed than the loading conveyor 5 and consequently it increases the distance between the wood pieces. The wood pieces are transported one by one along the separating conveyor 7 and onto a loading hatch 9. The loading hatch 9 is part of a vertical packing machine for preparing a stack of wood pieces ready for bagging.

[0054] It should be noted that since the distance created as shown in FIG. 3 will vary dependent on the height of the wood pieces, then it can be important, when seeking to have a controllable time period between wood pieces to set the speed of the first conveyor accordingly. The minimum time interval between the wood pieces which are entering the packing machine is not dependent on the measured distance (length) between the wood pieces, but on the velocity of the loading conveyor 5. For example, assuming that there is no distance between the wood pieces then if the speed of the belt is 0.3 m/s and the wood pieces are an average of 0.3 m long, then one wood piece will reach the loading hatch every second. Decreasing the speed to 0.15 m/s would result in one wood piece reaching the loading hatch every 2 seconds. The greater velocity of the separating conveyor will increase the spatial distance between the wood pieces, but of course this does not affect the time period between the wood pieces.

[0055] The loading hatch 9 has a door preferably in the form of a pair of flaps opening downward and having a truncated V shape when closed. When a wood piece is slid onto the loading hatch 9 by the conveyor 7 and is detected by sensors, then the loading hatch 9 opens. The wood piece is dropped in a stable orientation into a buffer compartment 10. The buffer compartment 10 can hold several wood pieces acting as a buffer to temporarily store wood pieces whilst a lower stage of the vertical packing machine (described below) is unloading wood pieces into a bag. This avoids the need to stop the conveyors 5, 7 when a hatch 13 of the lower stage (measuring compartment) is opened.

[0056] The buffer compartment 10 is provided with a buffer compartment hatch 11 operating in a similar manner to the loading hatch 9. The buffer compartment hatch 11 is closed when the hatch of the lower stage is opened. As with the loading hatch 9, the buffer compartment hatch 11 enables the wood pieces to be dropped in a stable orientation. The buffer compartment hatch 11 preferably has a similar door with a pair of flaps opening downward with a V-shape.

[0057] Below the buffer compartment 10 is a lower stage having a measuring compartment 12 with room for typically 7.5 kg or 20 litres of wood pieces. The volume of wood packed using the example embodiment might be 75% wood and 25% air. Sensor(s), such as for example a weight sensor, detect when the measuring compartment 12 contains the required amount. This stops the buffer compartment hatch 11 from opening and opens a measuring compartment hatch 13. The measuring compartment hatch 13 may be similar to the hatches 9 and 11. The wood pieces are dropped in a stable orientation with the length of the wood pieces horizontal, and they fall into a bag rack 14. A net bag 15 or the like is fitted to the bag rack 14 and when this is disengaged and slid downwards off the bag rack 14 then it will be filled with the specified quantity of wood pieces, which will all be correctly oriented and which will be efficiently packed into the bag 15. The bag 15 can be filled in one step or in some cases the bag 15 may be filled in two stages. For example, with the measuring compartment mentioned above the apparatus may fill the bag with two 20 litre batches to reach 40 litres (approximately 15 kg of dry wood).

[0058] The bag 15 can be fitted and removed manually, or it can be done automatically.

[0059] The apparatus includes a controller or multiple separate controllers to receive inputs from sensors and to control the various mechanisms of the apparatus. Thus, the controller(s) may receive data from the sensor(s) at the measuring compartment 12 and from the sensor(s) at the loading hatch 9; and the controller(s) may control the loading hatch 9, the buffer hatch 11 and the measuring compartment hatch 13 so that the apparatus operates as described above. The controller(s) may also be connected to other systems in order to permit control of the conveyors 5, 7, the waste extraction machine 2 and so on during operation of the machine.

[0060] FIG. 4 shows another example of a wood packing device. This has the same basic parts and stages as the apparatus of FIG. 1. A loading hopper 18 is added, which ideally has sufficient capacity to keep the machine supplied for an hour or more before refilling is required. The loading hopper 16 supplies wood via a conveyor to the waste extraction/wood cleaning machine 2, which can be of similar design to that described above with reference to FIG. 2. The cleaned wood exits the waste extraction/wood cleaning machine 2 onto a channel 4.

[0061] The channel 4 of FIG. 4 has a different design to that of FIG. 1. In order to decrease the risk of multiple wood pieces sliding down the channel 4 together, and to provide additional spacing between wood pieces, the channel 4 has a first downwardly sloped portion followed by a flatter (less sloped, and optionally horizontal) section and then a second downwardly sloped portion. The flatter section and the second downwardly sloped section have lower sidewalls than the first downwardly sloped section. Should it occur that two wood pieces exit the waste extraction/wood cleaning machine 2 together and slide down the first downwardly sloped part of the channel 4 together, then these wood pieces will become separated at the flatter section, and all but one piece will fall off the sides. A hopper 19 and conveyor 20 return any falling pieces to the main hopper 18. Whilst this design cannot absolutely guarantee that the wood piece will slide down the second downwardly sloped section one-by-one, and arrive at the loading conveyor 5 one-by-one, it has been found that the risk of two wood pieces descending the channel 4 together is greatly reduced when the flatter section is introduced. The reduced height of the sidewalls in the flatter section and the second downwardly sloped section also increase the likelihood that the wood pieces will be aligned lengthwise one-by-one as they reach the loading conveyor 5.

[0062] As for FIG. 1 the channel 4 in FIG. 4 allows sliding movement powered only by gravity and by the speed of the wood pieces entering the channel 4 from the waste extraction/wood cleaning machine 2. Again, however, this channel 4 could be replaced by a channel 4 using a conveyor mechanism as shown in FIGS. 5 and 6, for example.

[0063] In the example of FIG. 4 the loading conveyor 5 interacts with the second downwardly sloped section of the channel 4 as shown in FIG. 3 for the channel 4 of FIG. 1. The loading conveyor 5 and the subsequent conveyor 7 are also similar to FIG. 1, and they supply the wood pieces one-by-one to the loading hatch door 9. In the example of FIG. 4 the device for filling the bags has a slightly different design to that of FIG. 1. The buffer compartment is dispensed with so that there are just two sets of hatches, the loading hatch 9 and the measuring compartment hatch 13. In this example the device for filling the bags has a side door 21, which can be opened for maintenance or to clear blockages if necessary. The wood pieces, when measured, are dropped into a bag (no shown in FIG. 4) held by the bag rack 14. The measuring compartment and/or the bag rack 14 advantageously taper outward toward the base, in order to minimise the risk of wood pieces becoming jammed. The bag rack 14 may have one hinged side to make it easier to but on an new bag, by pressing the hinged side towards the fixed side to make a cone as you pull up the bag. When the wood drops down, both the hatch moving to vertical position and the falling wood itself will help open the bag holder to full depth. The hinged side is also useful for avoiding jams and could be arranged to open beyond vertical so that there is an outward taper toward the base when the bag is filled.

[0064] It will be appreciated that these features of the device for filling the bags could be used, individually or in combination, with the FIG. 1 example. Likewise, the three-part channel 4 could also be used with the apparatus of FIG. 1.

[0065] FIGS. 5 and 6 show another alternative design for the channel 4 that conveys the wood pieces from the waste extraction/wood cleaning machine 2 to the upwardly sloped conveyor 5. In this case the channel 4 is a V shaped conveyor channel 4 comprising a static wall 22 and a conveyor wall 23 at an angle to each other meeting at the vertex of the V shape. The use of an arrangement where the wood pieces are partly supported by the static wall 22 and partly supported by the conveyor that forms the conveyor wall 23 has been found to give low enough friction not to force wood pieces onto the subsequent upwardly sloped conveyor 5 before a gap is formed, whilst also acting to move the wood pieces along as they exit the waste extraction/wood cleaning machine 2 in order to thereby ensure that the logs stack end-to-end. By providing some mechanical assistance to movements of the wood pieces along the V shape channel 4 it can also become possible to increase the speed at which the wood pieces pass through the system, which allows for quicker packing of the wood pieces. As noted above the V shape conveyor channel 4 of FIGS. 5 and 6 can be used with the apparatus of FIG. 1 or the apparatus of FIG. 4.