Patent Application
20090076741
This invention relates generally to measuring cut lumber in a sawmill, and more specifically concerns a distributed system for measuring lumber which can be used in a single or multiple zones in the sawmill.
Systems for measuring lumber produced by sawmill cutting operations are known. One such known system measures every cant and board as they are produced, monitors board size in real time, and send alarms when the boards are not within specification. This provides an automatic method for monitoring sawing accuracy, generally providing higher quality and grade yields.
Because of the distance between the single centralized electrical cabinet 24 which services all of the scan zones, including the individual lasers in the scan zones, the connecting cable typically must be pulled through conduits which extend between the electrical cabinet and the scan zone locations. The installation of such a system usually requires a special crew and installation at off hours of the sawmill. The physical connections between the connecting cable and the lasers and the laser concentrator, respectively, must be done on-site, including soldering and other termination connections. In order to ensure correct connections, an installation team must be on-site for inspection of the system, in order to ensure safety of the components of the system, particularly the lasers, which can be easily damaged by incorrect wiring. All of the above makes installation expensive, time-consuming and labor-intensive, requiring specialized personnel from the provider of the system.
It would be desirable to have a measuring system for lumber (cut boards) which could be accurately and quickly installed by sawmill employees. Further, it would be desirable to be able to move a board measuring system from zone to zone in a sawmill.
Accordingly, the present invention is a system for measuring lumber in a sawmill, comprising: a local scanning system for at least one scan zone, including: a pair of lasers for imaging cut lumber in the one zone, an electrical box containing a data display, a signal converter and a power supply, the electrical box being located within a short distance of the lasers; and electrical cables for supplying power from the power supply in the electrical box to the lasers and for transmitting data between the lasers and the signal converter, the cables having pre-wired connectors on the ends thereof for connecting to mating electrical connectors on the electrical box and the lasers; and a computer for receiving and processing data from the lasers and for transmitting results of the processing for display on the data display, wherein the system permits a plug and play installation by a user without making incorrect wiring connections within the system.
One power supply 40, 7.5VDC, is connected to a large character reader board display 42 in electrical box 32. A second power supply 43, 12 VDC, is connected to a conventional four port Ethernet to RS422 multiport converter 46, also referred to generally as a signal converter, for power and data. A third power supply 45, 24 VDC, is for lasers 34, 36. The Ethernet converter 46 connects to the large character display 42, MS-style connectors 50 and 52 for laser cables 38 and 39 and to an Ethernet switch 48, to which is also connected a fourth power supply 49, 7.5 VDC. Two ports from switch 48 are connected to external RJ45 industrial connectors 51, 51A. Connector 51A connects to computer 31 by a standard CAT5 cable 53. The other connector 51 permits connection to other electrical boxes in a multi-zone arrangement, as discussed below. The computer 31 can also be part of a network. The connectors 50, 51, 51A, 52 and 54 are all mounted in a side panel 56 of electrical box 32.
In a variation of the arrangement of
Connecting each laser 34 and 36 to MS connectors 50 and 52 are laser cables 38 and 39. The laser cables 38 and 39 have MS connectors at both ends thereof. The connector on one end of each cable screws into an associated single point laser, while the connector on the other end of each cable connects to the MS connector mounted on panel 56 of electrical box 32. The laser cables are relatively short, typically less than 30 feet, because electrical box 32 is mounted nearby the lasers. The user is able to observe the board information produced by the lasers and the computer on reader board display 42, which, being in electrical box 32, is nearby the sawmill scan zone associated with the display. The display is typically color coded; for instance, green can be used for boards within tolerance results, red for below the lower tolerance limit and orange for above the upper tolerance limit. The connectors on the ends of the laser cables 38, 39 are mounted prior to shipment of the system to end users. The connectors on the laser cables are configured so that they fit in only one position to both the connectors on the lasers and the connectors on electrical box 32. This arrangement prevents connection errors and helps make installation of the system simple, straightforward and reliable.
The above system is convenient to install by sawmill personnel in normal course, without shutting down the mill operation, since there are no long cable runs and thus no need for conduits. Since the Ethernet cable and the laser cables are all pre-wired with connectors on both ends, there is also no chance of wiring errors by the customer in their installation of the cables to the lasers and to the connectors at the electrical box.
In installing the system, a sawmill customer will locate an electrical box locally to a selected scan zone, within a relatively short distance from the scan zone lasers, for instance, 30 feet. The cables provided with the system are then connected to the system computer and the two lasers. Software is provided in the system configuration to process the laser information and provide display/warning information to the display in each zone. The hardware in the system, including the lasers, the display unit and the Ethernet converter, may be tested at the manufacturer's facility and pre-configured for a specific customer. The system is ready to be powered-up and used immediately after installation, referred to as a plug and play system. No specialized installation/set-up team from the manufacturer is necessary and the installation can be accomplished during normal operating hours, if desired, with minimal interruption of normal sawmill operations.
The system of
Hence a lumber measuring system has been described which has the advantage of simple, low-cost installation, not requiring specialized installation personnel. The customer is able to take the system as delivered and conveniently install it, without risk of incorrect wiring or system connection, thus saving expense and the time of the system provider.
Although the above system utilizing local enclosures/boxes with power supplies and other elements connecting to lasers is described for measuring boards in the context of a sawmill application, it should be understood that the principles of the above system can be used in other industries and applications for monitoring of various manufactured items.
Although a preferred embodiment of the invention has been disclosed for purposes of illustration, it should be understood that various changes, modifications and substitutions may be incorporated in the invention without departing from the spirit of the invention which is defined by the claims that follow.
