Lineally scanned cutters are used throughout the lumber cutting industry. An example of a lineally scanned cutter is a lineal edger that removes the waste edges off of partially sawn logs. Another example of a lineally scanned cutter is a lineal gang saw configured to gang rip saw the work piece to create two or more sawn work pieces.
One example of a conventional forest products lineal cutter assembly is illustrated in
Work piece clamping station 6 has feed chain bed 14 and two hold down rollers 15. Feed chain bed 14 is separated from scan belt 4 by a gap 25, typically 12 to 18 inches; see
The current transport system of
The transport system as illustrated in
Sharp top roller chain 20 starts out with sharp points to hold work piece 2 firmly. After only a few days of operation, the sharp points of sharp top chain 20 widen out and get flat due to normal wear of transporting work piece 2 through cutting station 7. When this happens, the sharp top chain 20 has a greatly reduced grip on the work piece 2, and work piece 2 can actually slide a little on sharp top chain 20 causing inaccuracies in the transport of work piece 2. These transport inaccuracies can cause cutting station 7 to saw work piece 2 along lines other than the optimized saw lines as predicted by the scanner and optimization computers. Examples of conventional forest products lineal cutter assemblies are sold by CAE Newnes McGehee of Salmon Arm, British Columbia, Canada as Lineal Edge System and Lineal Gang Line System and by United States Natural Resources (often referred to as USNR) of Woodland, Wash., USA. Examples are also disclosed in the following U.S. Pat. No. 6,705,363 entitled Log Processor and Method; U.S. Pat. No. 5,870,936 entitled Edge Trimming and Board Ripping Apparatus and Method; U.S. Pat. No. 5,761,979 entitled Edge Trimming and Board Ripping Apparatus and Method; U.S. Pat. No. 5,722,474 entitled Method and Apparatus for Cutting a Cant into Boards; U.S. Pat. No. 7,017,632 entitled Position-Based Integrated Motion Controlled Curve Sawing; and U.S. Pat. No. 6,062,280 entitled Method and Apparatus for Scanning, Optimizing and Edging a Board with and an Active Edger.
Examples of conventional scanning and optimizing computer systems are sold by United States Natural Resources of Woodland, Wash., USA and CAE Newnes McGehee of Salmon Arm, British Columbia, Canada. Examples are also disclosed in the following U.S. Pat. No. 4,867,213 entitled System for Orienting Logs for Lumber Processing; U.S. Pat. No. 5,884,682 entitled Position-Based Integrated Motion Controlled Curve Sawing; U.S. Pat. No. 6,219,585 entitled Three Dimensional Log Scanning Device for a Log Positioning and Saw System; and U.S. Pat. No. 6,463,402 entitled Infeed Long Scanning for Lumber Optimization.
An example of a forest products lineal cutter assembly comprises a work piece scanning assembly, an outfeed conveyor assembly and a cutting station. The work piece scanning assembly comprises a scanning conveyor and a scanner, the scanning conveyor having a scan belt with a first entrance end and a first exit end. The scanner is located between the first entrance end and the first exit end. The outfeed conveyor assembly comprises an outfeed belt having a second entrance end. The cutting station is positioned between and adjacent to the first exit end and the second entrance end. The lineal cutter assembly also includes a first work piece hold down element above the scan belt at the first exit end and a second work piece hold down element above the outfeed belt at the second entrance end. In some embodiments the first work piece hold down element comprises a first hold down roller and the second work piece hold down element comprises a second hold down roller.
An example of a method for working on a forest products work piece is carried out as follows. A work piece is directed onto a first entrance end of a moving scan belt of a scanning conveyor. The work piece is moved on the moving scan belt past a work piece scanner and to a first exit end of the scan belt. The work piece is biased against the scan belt at the first exit end. The work piece is moved on the moving scan belt from the first exit end directly to a cutting station, the cutting station being adjacent to the first exit end. The work piece is passed through the cutting station and directly to a second entrance end of an outfeed belt of an outfeed conveyor assembly to create a modified work piece, the cutting station being adjacent to the second entrance end. The modified work piece is biased against the outfeed belt at the second entrance end. The modified work piece is moved along the outfeed belt. In some embodiments the work piece is biased against the scan belt using a first hold down roller. In some embodiments the modified work piece is biased against a second hold down roller.
Other features, aspects and advantages of the present invention can be seen on review of the Figures, the detailed description, and the claims which follow.
The present invention is directed to an improved work piece transport apparatus and method which provides a greatly simplified approach to transporting work pieces in lineally optimized cutting systems.
The following description will typically be with reference to specific structural embodiments and methods. It is to be understood that there is no intention to limit the invention to the specifically disclosed embodiments and methods but that the invention may be practiced using other features, elements, methods and embodiments. Preferred embodiments are described to illustrate the present invention, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a variety of equivalent variations on the description that follows. Like elements of the prior art embodiments and the various embodiments of the present invention are commonly referred to with like reference numerals.
One of the primary advantages of the invention is its simplicity. The invention effectively replaces the chain bed, with its sharp top roller chain 20, chain guide track 21 and sprockets 22, by extending scan belt 4 beneath hold down rollers 15. The invention also replaces bed rollers 24 by extending out feed belt conveyor 11 beneath hold down rollers 15A. The scan belt 4 of the present invention has a much higher coefficient of friction than the feed chain 20 of
An additional advantage of the invention is the increased feeding accuracy of the work piece. The elimination of transitions from the scan belt 4 to the feed chain bed 14 of conventional systems eliminates all inaccuracies associated with handing the work piece off from one feed section to another. In a conventional system there are several hand off points including the transition from the feed chain bed to the out feed work piece clamping station, and the transition from the out feed station to the out feed belt conveyor. The present invention has no transition before the cutting station 7 assuring that the work piece is in the same orientation passing through the cutting station as it had when it passed the scanner 5.
The above descriptions may have used terms such as above, below, top, bottom, over, under, et cetera. These terms are used to aid understanding of the invention are not used in a limiting sense.
While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is to be understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the following claims.
Any and all patents, patent applications and printed publications referred to above are incorporated by reference.
1. Acceleration rollers
2. Rough work piece
3. Feed direction
4. Scan belt
5. Scanner
6. Work piece clamping station
7. Cutting station
8. Waste edges
9. Finished work piece
10. Additional work piece clamping station
11. Out feed belt conveyor
12. Waste separator station
13. Top out feed belt
14. Feed chain bed
15. Hold down rollers
15A. Hold down rollers
16. Leading end of work piece
17. End of scan belt
18. Sideways motion
19. Saw cuts
20. Sharp top roller chain
21. Chain guide track
22. Sprocket
23. Acceleration station
24. Bed rollers
25. Gap
26. Gap
28. Cutter
30. Forest products lineal cutting assembly
40. Entrance end of work piece scanning assembly
42. Work piece scanning assembly
44. Entrance end of out feed belt
46. Out feed belt
This application claims the benefit of U.S. patent application No. 60/939,767 filed 23 May 2007, Attorney Docket number MGDC 1005-1.
Number | Date | Country | |
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60939767 | May 2007 | US |