CA2851910A1

CA2851910A1 - Aligning lug loader

Info

Publication number: CA2851910A1
Application number: CA2851910A
Authority: CA
Inventors: Darryl Kujat; Douglas Foster; Darren Ross
Original assignee: USNR Kockums Cancar Co
Current assignee: USNR KOCKUMS CANCAR HOLDINGS ULC
Priority date: 2007-02-07
Filing date: 2007-02-07
Publication date: 2008-08-07
Anticipated expiration: 2027-02-07
Also published as: CA2577656A1; CA2851910C; CA2577656C

Abstract

A virtual lug loader includes a lug loader for loading workpieces in a flow direction into the spaced apart lugs on a lugged conveyor, wherein the workpieces are transversely oriented relative to the flow direction. The lug loader includes an array of overlapping pairs of endless conveyors for conveying the workpieces downstream, wherein each pair of endless conveyors in the array include first and second endless conveyors spaced laterally apart across the flow direction and aligned substantially in the flow direction. The array forms a continuous upper surface in the flow direction for supporting the workpieces. At least one pair of endless conveyors in the array includes independently actuable first arid second drives independently operable to drive the corresponding first and second endless conveyors to advance an upstream end of a workpiece relative to a downstream end of the workpiece to correct workpiece skew.

Description

ALIGNING LUG LOADER
Field of the Invention This invention relates to an apparatus for the singulation or allocation of lumber into lug spaces on a lugged transfer, or other lumber conveying device, and in particular relates to an apparatus capable of collecting, singulating, straightening, allocating and consistently spacing, rough sawn lumber or planed finished lumber, or sticks of varying widths, thickness and lengths into consecutive spaced-apart lugs, or allocated spacings onto a transfer, or lugged transfer, or to a stick placing device, at high speeds.
Background of the invention Conventional lug loaders or singulators (hereinafter collectively referred to as either lug loaders or singulators) have been found to be inadequate at higher feed speeds.
They are also limited in their ability to both singulate and allocate lumber.
When lumber is of varying widths and varying in thickness, or bowed, as may be predominant in curve sawing mills, cupped or crooked, and/or skewed on the transfer, it becomes increasingly difficult to handle the lumber at desirable higher speeds.
An example of a conventional lug loader is that taught in U.S. Patent No.
3,923,142 which issued to Rysti on December 2, 1975. In particular, what is being taught is singulating boards by use of supporting arms rotating around a closed loop, the orientation of the supporting arms controlled by curved deflectors. Pressing arms in opposed radial pairs, are rotatably mounted above the supporting arm to synchronously clamp a board onto a supporting arm. Downstream flow of the mat of boards is arrested by a stop on each supporting arm. Rysti does not disclose a mechanism for straightening lumber which is skewed on the infeed transfer in the lug loader.

Applicants are also aware of U.S. Patent No. 5,518,106, which issued to Allard on May 21, 1996. Allard discloses using fixed pick-up shoes mounted onto rotating discs for engaging and supporting boards being singulated. Fixed shoes however, have the disadvantage that they may mark the underside of the board as the board is translated over the top of the disc and as the board is released. If a board is finished, for example destined for cabinet making or the like, then any marks from the shoe or overhead clamp will reduce the value of the board. Allard also discloses a speed-up belt to pull the board away from the fixed shoes at the top of the disc to prevent the board from being flipped over as the board is released from the shoes. In some mills the boards have been marked for trimming and grading before the lug loader.
Thus if the board has been flipped over by the singulator, as may occur in the case of the Allard device, the board must be flipped back by hand to read the mark. This can be difficult in a high speed application.
Many lug loaders in the prior art, particularly those operating at slower feed speeds, require that, in order to stop the delivery of boards to the singulator, the board mat moving downstream into the singulator device must be pushed back upstream by the stopping means, that is forced away from, for example, the fixed pick-up shoe and clamping device.
Worse yet, in some prior art devices the board delivery mechanism must be brought to a complete stop. Both pushing the mat of boards back upstream, and stopping the board delivery mechanism, can be impractical at high speed.

2 C
In the prior art applicant is also aware of U.S. Patent Nos. 5,921,376 and 6,199,683 which issued to Michell et al for, respectively, a High Speed Revolving Lug Loader With Retracting Heel and Hook and a High Speed Revolving Board Singulator With Retracting Shoe and Variable Dwell Duckers, both of which describe the mechanical manipulation of boards to load the boards into individual lug spaces in a lugged outfeed transfer.

Applicant is also aware of the following U.S. Patent Nos. in the prior art relating to the present invention: 4,077,524; 4,144,976; 4,330,055; 4,638,440; 4,869,360;
5,419,425;
5,662,203; and 5,813,512.
Summary of the Invention The proposed invention is a transfer system. The transfer system makes use of conveyors such as chains or belts to move lumber pieces downstream while oriented traversely across the flow path. The lumber pieces enter the virtual lug loading system according to the present invention moving transversely. The lumber pieces may enter as a tightly spaced sheet or mat of pieces with no gaps, or the lumber pieces may be randomly spaced and oriented.
Within the system a first grouping of transfers create consistent gaps between individual lumber pieces. The speed with which the lumber pieces are translated downstream is varied to create spaces between the lumber pieces. The first group of transfers may be driven individually or ganged together. In one embodiment individual transfers or pairs of transfers arc selectively and independently actuable to vary their speeds so that the gaps may be created, for example, by increasing the velocity of successive transfers in the downstream direction.
The transfers in the second grouping of transfers are individually driven.
They maintain the gapping, that is the spacing between lumber pieces, and allow a surge capacity.
Being individually driven, these transfers also provide for skew correction should the lumber pieces arrive skewed or skew during a transition from one transfer to another.
These transfers gap and straighten the pieces as required so that one piece is positioned into each lug space on downstream lugged transfer chains. Thus, individually driven belts within this second grouping of transfers provide skew correction to correct the orientation of skewed lumber pieces on the infeed to the lugged transfer being loaded. Keeping the lumber pieces straight, that is oriented traversely across the flow path on the infeed, helps deal the lumber pieces into the lug spaces.

3 Dealing the boards directly into lug spaces without a mechanical lug loader simplifies the loading of the lug spaces in the lugged transfer as compared to the prior art. It improves operator access, and reduces the amount of mechanical components requiring maintenance.
In one aspect of the present invention, servo controlled decks singulate the lumber pieces and position them directly into a lugged chain.
In summary the virtual lug loader according to one aspect of the present invention includes a lug loader for loading workpieces in a flow direction into the spaced apart lugs on a lugged conveyor, wherein the workpieces are transversely oriented relative to the flow direction.
The lug loader includes an array of pairs of endless conveyors for conveying the workpieces downstream, wherein each pair of endless conveyors in the array include first and second endless conveyors. The first and second endless conveyors are spaced laterally apart across the flow direction. Each are aligned substantially in the flow direction. The array forms a continuous upper surface in the flow direction for supporting the workpieccs translating downstream in the flow direction. Each pair of endless conveyors in the array overlap adjacent pairs of endless conveyors in the array. At least one pair of endless conveyors in the array include independently actuable first and second drives independently driving their corresponding first and second endless conveyors.
When a skewed workpiece, that is one which is skewed from its transverse orientation, is translating on the first and second endless conveyors, the first or second drive corresponding to one of the pair of endless conveyors advances the upstream-most end of the workpiece relative to its downstream-most end to correct the workpiece to an un-skewed position oriented transversely to the flow direction.

4 The array may include an upstream gapping section and a downstream lug loading section. Advantageously, the first and second endless conveyors, that is the pair or pairs of conveyors which are independently actuable so as to correctly orient skewed workpieces. is or are found within the lug loading section. However, it is not intended as limiting the scope of the present invention to have only gapping sections followed by skew correction sections. It is intended that in the present invention also to interleaf gapping sections with skew correction pairs.
Further, skew correction could be done anywhere within the transfer system instead of j ust the lug loading section.
The pairs of endless conveyors in the gapping section may translate the workpieces in the flow direction at increasing downstream velocities between an upstream end of the gapping section and a downstream end of the gapping section. The increasing downstream velocities may be successively increasing downstream velocities corresponding to successive pairs of endless conveyors between the upstream and downstream ends of the gapping section.
The number or proportion of endless conveyors either overall to the system, or within the lug loading section, which are the independently actuable pairs of endless conveyors may be for example, not intended to be limiting, substantially half of the number of pairs of endless conveyors.
The independently actuable pairs of endless conveyors each have corresponding selectively actuable drives so that each of those pairs of endless conveyors is asymmetrically actuable to drive one endless conveyor ahead of another endless conveyor to correct skew of a workpiece on any one of those endless conveyors.
The adjacent pairs of endless conveyors in the array may overlap at adjacent ends thereof by one endless conveyor of the adjacent pairs being inset laterally across the flow direction relative to a corresponding second endless conveyor of the adjacent pairs.

5 The present invention also is intended to include within its ambit a method of virtual lug loading corresponding substantially to the use of the above described apparatus.
Brief Description of the Drawl=
Figure 1 is a side elevation view of the virtual lug loader according to the present invention shown in an elongated view having component views in Figures 1A. I B
and 1C intended to be viewed side-by-side in sequence.
:0 Figure 2 is a plan view of the virtual lug loader of Figure 1 shown in an elongated view having component views in Figures 2A, 2B and 2C intended to be viewed side-by-side in sequence.
Figure 3 is the lug loader of Figure 2 showing, diagrammatically, sensors and controls.
Detailed Description of Embodiments of the Invention As seen in the accompanying figures wherein similar characters of reference denote corresponding parts in each view, the Virtual Lug Loader according to the present invention includes a gapping section 10 immediately upstream, relative to a direction of flow A, of lug loading section 12. Workpieces 14 arrive in direction A so as to form a mat or blanket 16 of workpieces 14 on infeed transfer 18. Workpieces 14 arriving at the upstream end of infced transfer 18 may be fed from, for example, a tilt hoist, a landing table, an unscrambler, or other wood handling machinery.

6 Mat 16 is formed on infeed transfer 18 as the workpieces are slowed on transfer belts 20. At the downstream end of infeed transfer 18, workpieces 14 are urged onto the upstream ends 22a of a first pair of belts 22 for progressively faster translation of each workpiece 14 in direction A as the workpicces are transferred from the downstream end of infeed transfer 18 onto sequentially and progressively faster successive pairs of belts 22, 24, 26, 28, and 30 within gapping section 10. Gapping section 10 may, alternatively, may be thought of as a lumber separation zone. Thus, a workpiece 14 having a velocity Vo in direction A on infeed transfer 18, will, once handed off to the first pair of belts 22, have a downstream velocity VI, and then sequentially increasing velocities V2, V3, V4, Vs thereby sequentially increasing the separation between individual work pieces 14 by reason of the progressive acceleration of the boards between pairs of belts.
Advantageously, the separation between individual workpieces 14 is increased as the length of the gaps, distance g between adjacent workpieces is increased for example to approximately one hundred twenty-five per cent of the length of each lug space, distance 1, between lugs 32a of lugged outfeed chains 32. It is understood that, although five pairs of belts 22-30 are illustrated, it is not intended to limit the present invention to five pairs of belts in gapping section 10 as more or fewer pairs of belts will suffice so long as sequential workpieces 14 are separated in direction A so that gap distance g is at least equal to lug space distance 1.
The pairs of belts 22,24, 26, 28 and 30 in gapping section 10 may each be driven by variable frequency drives or induction motors 34 along with associated gear heads. In the illustrated example, not intended to be limiting, each of the five speed-up zones corresponding to the five belt pairs are approximately sixteen inches long so that the length in the downstream direction of gapping section 10 is approximately six foot, eight inches.
In a preferred embodiment, lug loading section 12 is immediately downstream, and cooperates with, the downstream end of gapping section 10 so that workpieces 14 are smoothly

7 handed off from belts 30, being the downstream most pair of belts in gapping section 10, to the first pair of control zone belts 36 located immediately downstream of the interface B between gapping section 10 and lug loading section 12. Lug loading section 12 is a workpiece control zone wherein skew may be corrected such as the skew of a workpiece 14' illustrated in dotted outline on control zone belts 38. Skew correction is accomplished by each belt in each pair of control zone belts 36, 38, 40, 42, 44, and 46 being able and adapted to selectively operate at different speeds. In order to correct skew, for example a skew angle alpha (a) of a skewed workpiece 14' the two belts 38, and subsequent downstream belts as need be, are driven at different speeds relative to one another as board 14' passes over the belts, so that the lagging end of the boar catches up with the advanced end of the board until the board is correctly positioned perpendicularly across the direction of flow A.
Apart from operating to correct the skew of workpieces translating downstream in direction A, the independently actuable control zone belts in the belt pairs of lug loading section 12 also, in addition to those belts in gapping section 10, operate to selectively space the boards apart and synchronize the boards with upcoming lugs 32a as the lugged outfced chains 32 rotate in direction C. Thus the control zone belts are driven by a motion controller (not shown) to accelerate or decelerate pairs of belts 36, 48, 40, 42, 44 and 46 to simultaneously accclerate.or decelerate both belts in individual pairs of belts so as to accelerate or decelerate a workpiece which has been corrected for a skew. This is done to synchronize and match the placement of a particular workpiece into, for example, the middle of a corresponding lug space as the workpiece exits the downstream end of lug loading section 12. Thus as may be seen, the acceleration or deceleration of the sequence of workpieces 14 being translated downstream over the sequential array of pairsof belts 38, 40, 42, 44 and 46, are selectively motion controlled so as to place a workpiece 14 entering onto the upstream end of the lugged outfeed chains 32 preferably into for example the middle of a corresponding lug space or otherwise exiting off the downstream end of belts 46 just after a pair of lugs 32a rotate to the vertical as chains 32 rotate endlessly around sprockets 48.

8 In the illustrated embodiment, not intended to be limiting, lug loading section 12 has six control zone belt pairs may be thought of as six belt modules each approximately sixteen inches long in the downstream direction for a total downstream length of eight feet. In one preferred embodiment, the motors 50 which selectively individually drive each belt in each belt module, may be servo motors having corresponding gear heads.
It is understood that sensors 52 such as seen in Figure 3 and known in the prior art, and as would be known to one skilled in the art, would be provided to detect the position of individual boards and that the information from the sensors is processed by a digital processor 54 cooperating with the sensors and that the digital processors also cooperates with a programmable logic controller (PLC) 56 via network 58 which in turn cooperates with the motors for selectively driving the belts 22, 24, 26, 28 and 30 in gapping section 10 and belts 36, 38, 40, 42, 44 and 46 in lug loading section 12.
In interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps maybe present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention.
Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.

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Claims

CLAIMS:

1. A lug loader for loading workpieces, the lug loader comprising:
an array of pairs of endless conveyors, each pair of endless conveyors including a first and a second endless conveyor spaced laterally apart across a flow direction and substantially aligned in said flow direction, wherein said array forms a continuous upper surface for supporting a workpiece translating downstream in said flow direction, the pairs of endless conveyors overlapping in said flow direction, wherein at least some of the pairs of endless conveyors form a section configured to adjust a gap distance between the workpiece and a next consecutive workpiece, the section including a first and a second of the pairs of endless conveyors, the first of the pairs of endless conveyors selectively operable to accelerate or decelerate the workpiece from an initial velocity to a first velocity and the second of the pairs of endless conveyors selectively operable to accelerate or decelerate the workpiece to a second velocity different from the first velocity, wherein the second of the pairs of endless conveyors is downstream of, and overlaps, the first of the pairs of endless conveyors.

2. The device of claim 1 wherein at least one of the one or more pairs of endless conveyors includes independently actuable first and second drives operable to independently drive corresponding said first and second endless conveyors, respectively.

3. The device of claim 2 wherein said at least one of the one or more pairs of endless conveyors is configured to be selectively asymmetrically driven by the independently actuable first and second drives to adjust a skew angle of the workpiece.

4. The device of claim 3 wherein said least one of the one or more pairs of endless conveyors is configured to be selectively symmetrically driven by the independently actuable first and second drives to cause acceleration or deceleration of the workpiece.

5. The device of claim 1, wherein substantially half of the first and second endless conveyors have corresponding selectively actuable drives.

6. The device of claim 1 wherein the pairs of endless conveyors in said array overlap at adjacent ends thereof by one endless conveyor of said adjacent pairs being inset laterally across said flow direction relative to a corresponding second endless conveyor of said adjacent pairs.

7. A method for loading workpieces onto a lugged conveyor from a transfer having an array of pairs of endless conveyors, each pair of endless conveyors including a first and a second endless conveyor spaced laterally apart and substantially aligned in a flow direction, wherein said array forms a continuous upper surface in said flow direction for supporting the workpieces translating downstream in said flow direction, the method comprising:
placing the workpieces onto the array of pairs of endless conveyors; and creating gaps between the workpieces by driving a first of the pairs of endless conveyors at a first speed to accelerate or decelerate the workpieces to a first velocity and driving a second of the pairs of endless conveyors at a second speed to accelerate or decelerate the workpieces to a second velocity different than the first velocity as the workpieces are translated downstream on the array, wherein the acceleration or deceleration of the workpieces creates the gaps between the workpieces.

8. The method of claim 7, further including driving a third of the pairs of endless conveyors asymmetrically to correct a skew angle of at least one of the workpieces, wherein the third of the pairs of endless conveyors includes independently actuable first and second drives independently driving corresponding said first and second endless conveyors, respectively.

9. The method of claim 7 wherein said array includes a gapping section and a lug loading section, wherein said first and second of the pairs of endless conveyors are within said gapping section, and wherein creating gaps between the workpieces includes driving the first and second of the pairs of endless conveyors in said flow direction at increasing downstream velocities between an upstream end of said gapping section and a downstream end of said gapping section.

10. The method of claim 8 further including symmetrically driving at least one of the pairs of endless conveyors in the lug loading section at a selected speed to accelerate or decelerate said at least one of the workpieces after correction of the skew angle.

11. The method of claim 7 wherein at least half of all said first and second endless conveyors of said pairs of endless conveyors have corresponding selectively actuable drives.

12. The method of claim 7 wherein the pairs of endless conveyors in said array overlap at adjacent ends thereof by one endless conveyor of said adjacent pairs being inset laterally across said flow direction relative to a corresponding second endless conveyor of said adjacent pairs.

13. A workpiece transport system comprising:
a plurality of conveyor modules arranged sequentially in a flow direction, each of said conveyor modules having a corresponding pair of endless conveyors spaced laterally apart across the flow direction and substantially aligned in the flow direction, the pairs of endless conveyors collectively forming a continuous support surface, wherein a first one of the pairs of endless conveyors is configured to accelerate or decelerate a workpiece to a first velocity, and a second one of the pairs of endless conveyors is selectively operable to accelerate or decelerate the workpiece to a second velocity, and wherein said first and second ones of the pairs of endless conveyors are selectively operable to adjust a gap between successive workpieces on the continuous support surface.

14. The workpiece transport system of claim 13, wherein at least one of the conveyor modules includes a drive configured to drive the corresponding pair of endless conveyors synchronously.

15. The workpiece transport system of claim 13, wherein at least one of the conveyor modules includes two or more drives selectively operable to drive the corresponding pair of endless conveyors asynchronously to thereby adjust a skew angle of at least one of said workpieces.

16. The workpiece transport system of claim 15, wherein two or more of the conveyor modules independently include two or more drives selectively operable to drive the corresponding pairs of endless conveyors asynchronously, and wherein said corresponding pairs of endless conveyors overlap along the continuous support surface.

17. The workpiece transport system of claim 13, further comprising:
a plurality of drives coupled to corresponding ones of the conveyor modules, the drives configured to drive one or more of the endless conveyors;
one or more sensors configured to detect positions of the workpieces on the continuous support surface;
a processor operatively coupled with the one or more sensors, the processor configured to process workpiece position information from the one or more sensors; and a controller coupled with the processor, the controller configured to operate at least some of the drives to adjust said gap.

18. The workpiece transport system of claim 17, wherein the workpiece position information includes skew information, a first and a second one of the drives being operable to drive one of said pairs of endless conveyors asynchronously to adjust a skew angle of at least one of the workpieces on the support surface.

19. The workpiece transport system of claim 17, wherein the controller is configured to synchronize placement of the workpieces onto a transfer downstream of the conveyor modules.

20. The workpiece transport system of claim 19, wherein the transfer comprises a lugged conveyor and the controller is configured to synchronize placement of the workpieces into corresponding lug spaces of the lugged conveyor.

21. A method for transporting workpieces in a flow direction, wherein the workpieces are oriented transverse to the flow direction, the method comprising:
providing a plurality of conveyor modules arranged sequentially in a flow direction, wherein each of said conveyor modules includes a corresponding pair of endless conveyors spaced laterally apart across the flow direction, and the pairs of endless conveyors of the conveyor modules collectively form a continuous support surface; and coupling a plurality of drives with corresponding ones of the conveyor modules, wherein each of the drives is selectively operable to drive at least one of the endless conveyors of the corresponding pair at a different velocity than an adjacent one of the pairs of endless conveyors to thereby adjust a gap between the workpieces.

22. The method of claim 21, wherein coupling the plurality of drives with corresponding ones of the conveyor modules includes coupling a first one of the drives with the endless conveyors of a first one of the conveyor modules, and wherein said first one of the drives is operable to drive said two or more of the endless conveyors synchronously.

23. The method of claim 21, wherein coupling the plurality of drives with corresponding ones of the conveyor modules includes coupling a first and a second one of the drives with a first and a second one of the endless conveyors of a first one of the conveyor modules, respectively, and wherein said first and second ones of the drives are operable to drive said first and second ones of the endless conveyors asynchronously to thereby adjust a skew angle of at least one of said workpieces.

24. The method of claim 21, further comprising:
providing one or more sensors configured to detect positions of the workpieces on the continuous support surface;
providing a processor operatively coupled with the one or more sensors, the processor configured to process workpiece position information from the one or more sensors; and providing a controller coupled with the processor, the controller configured to operate the drives to adjust said gap.

25. The method of claim 24, wherein the workpiece position information includes skew information, and wherein coupling the plurality of drives with corresponding ones of the conveyor modules includes coupling a first and a second one of the drives with a first and a second one of the endless conveyors of a first one of the conveyor modules, respectively, said first and second ones of the drives are operable to drive said first and second ones of the endless conveyors asynchronously to thereby adjust a skew angle of at least one of said workpieces.

26. The method of claim 24, wherein the controller is configured to synchronize placement of the workpieces onto a transfer downstream of the conveyor modules.

27. The method of claim 26, wherein the transfer comprises a lugged conveyor and the controller is configured to synchronize placement of the workpieces into corresponding lug spaces of the lugged conveyor.