Conveyors: power-driven – Conveyor system for arranging or rearranging stream of items – By laterally or vertically moving successive items in...
Reexamination Certificate
1999-04-30
2001-01-16
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveyor system for arranging or rearranging stream of items
By laterally or vertically moving successive items in...
C144S245100, C144S245200, C144S242100, C144S250230
Reexamination Certificate
active
06173829
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a board positioning fence for lumber trimmers, and in particular to a circulating paddle, board positioner with a flexible fence for following the trajectory of the end of the boards as the boards are ended and positioned.
BACKGROUND OF THE INVENTION
In a typical lumber mill or planer mill, each board is oriented transversely on a lugged transfer moving laterally towards the trimmer. Typically, the lugs on the transfer are evenly spaced at precise intervals. The boards are passed through an electronic scanner which determines the shape of each board and sends the shape information to an optimizer. The optimizer in turn sends the information to a controller. The controller adjusts a positioning fence and activates saws above a trimmer saw deck to trim the board in an attempt to maximize lumber utilization. Typically saws are spaced one foot apart or conversely two feet apart, so that depending upon the particular mill setup and the physical defects of a board, two feet of each end of the board could potentially be trimmed and thus wasted if the trim target is missed, this results in considerable wastage of useful wood and loss of profits.
In order to minimize such wastage, board positioners were developed utilizing a plurality of parallel rollers, or ending rolls, which are driven in a direction at right angle to the transfer deck, thus moving the ends of the boards up to a positioning fence. When on the rollers, the boards are continually thrust laterally across the transfer deck, until the board is raised above the rollers by a plurality of lift skids to disengage the board from the rollers at a predetermined place. Such prior art devices have the disadvantage that when wet or icy boards are being ended, slippage of the boards can cause a jerking movement in a manner which will cause chattering and bouncing of the boards on the ending fence and when the lift skids lift the board at the predetermined ending position, inaccuracies result. As well, the lift skids are complex, each requiring an activation cylinder and there is an extra control system needed to raise each skid group in time with the lugged transfer chains along the length of the ending fence as needed and if applicable, extending along the stages of the ending fence.
Such devices suffer from the fact that tapered ends of boards abutting the positioning fence can be so structurally weak as to collapse or break when contacting (bouncing, chattering) and sliding along the fence. Because the board was scanned and optimized based on the inclusion of the tapered ends, if the end is broken off, the optimized lengthwise movement of the board can be overshot as the broken board is ended against the positioning fence, resulting in a board that is over trimmed.
It is therefore an object of the present invention to provide a board positioning device which can gently and accurately position selected boards for trimming at a higher rate of speed than prior art devices and without damage or collapse of the board's weak ends, so as to thus provide an improvement in accuracy for optimally trimming boards.
In another problem with most existing apparatus of the general type, the setting of each board in sequence limits the time available to reset the next piece, also as speeds increase, more stages are added to allow for greater ending. This results in a longer installed length, and is therefor more difficult to retrofit, in addition as mentioned a multiple number of lift skids, which attempt to hold the boards position after ending, are needed in most board positioners which adds to the number of moving parts and the controls needed to operate these lift skids are also increased.
It is therefor another object of the present invention to provide an apparatus that will not require additional space and to also eliminate the need for lift skids and the controls needed to operate the lift skids in sequence with the lugged transfer chains.
SUMMARY OF THE INVENTION
The circulating paddle positioning fence with an adjustable flexible track comprises a plurality of circulating positioning paddles which are slidably mounted on a pair of parallel circulating chains mounted adjacent a trimmer transfer, where the trimmer transfer has lugged transfer chains. There are a plurality of ending rolls within the trimmer transfer which urge the boards towards an ending fence. The ending fence is mounted at the upstream end of the ending rolls. A board is ended up against the ending fence and then, as the board is translated downstream, the board is handed off to a corresponding circulating paddle when the circulating paddle is at its fully extended position. The ending rolls continue to urge the board towards the positioning paddles along the length of the positioning fence.
The positioning paddles are mounted on shafts, sleeves or slides which are slidably mounted on the circulating chains to allow lateral adjustment of the paddles as the paddles move with the flow of the boards. The boards are translated in the lug spaces on the trimmer transfer chains. The positioning paddles are circulating at the same speed as the trimmer transfer chains.
The paddles mounted to the shafts are positioned by the contact of a pair of side by side followers, mounted in close proximity to each other and mounted on to the shaft, with a closed-loop track consisting of rigid and flexible segments. From an upstream position, the followers first follow along a fixed track segment as the paddles come around to meet a corresponding board. The followers then follow a flexible track segment to cause the paddles to follow an adjustable configurable displacement curve. The rigid and flexible tracks are mounted between the pair of circulating chains. The fixed track segment is mounted at the upstream end of the circulating paddle positioning fence. The upstream end of the flexible track segment is attached to the downstream end of the fixed track segment. The fixed track is mounted to coincide so that the followers on the paddle shaft and the paddles move laterally to meet and pick up boards from the ending fence at the lumberline. The paddles are extended to their maximum when the paddles take over the end of a board from the ending fence. The end of the board follows the paddle downstream to the end of the circulating paddle board positioning apparatus.
To help ensure that the end of the boards maintain contact with the paddles, as the boards are urged by the ending rolls concurrently towards the trimmer and laterally towards the paddle, the flexible track forms a specific curve that helps the boards follow the path of the paddle. To help in forming the shape of the curve the flexible track takes, there may be a fixed shaped curve form mounted behind the flexible track where the flexible track connects to the fixed track. As the flexible track is adjusted by moving its downstream end to its predetermined position, the curved form backs onto the flexible track (just below the path of the followers) to help shape the flexible track to approximate the trajectory of the end of the board as the board is ended by the paddle as the paddle is translating to follow the shape of the flexible track.
The flexible track may be made of a spring steel band or other flexible material. The second end of the flexible track is then slidably attached to a lineal actuated trolley, where the trolley is activated by a setworks so as to adjust the trolley and thus the flexible track to a predetermined position as set by an optimized system for trimming the board to the desired length. The optimizer control system tracks the board from the scanner outfeed, so that the corresponding circulating paddle may be adjusted to position the board on the lugged transfer.
The paddle is positioned to set the board end for trimming by adjusting the trolley. The paddle followers such as pairs of rollers, then follow along the flexible track which has been conformed to its desired shape and ending position. The paddle followers will first follow the fixed track, t
Hannebauer James B.
Jackson James G.
CAE Electronics Ltd.
Edwards Antony C.
Ellis Christopher P.
Shapiro Jeffrey A.
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