Note: Descriptions are shown in the official language in which they were submitted.
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10545
IMPROVED FEEDING AND DATA ENTRY SYSTEM
FOR LUMBER TRIMMER
BACKGROUND OF THE INVENTION
This invention relates generally to trimmers for lumber and more
particularly to an improved feeding and data entry system for a trimmer.
In most lumber mills~ one of the last steps in the manufacturing
process is grading, trimming and sorting. Typically, when grading and
trimming dry lumber, stacks of lumber coming from dry kilns will be
disassembled and the pieces transversely conveyed to the grading station.
Usually several graders will visually observe each piece of lumber on one or
both sides and mark the piece with a trim indication and a grade indication.
The marks are most typically made with chalk on the ends passing by the
10 graders which can then be read by the trimmer operator.
The marked boards are then conveyed to a lug loader. The lug
loader acts as a stop for the boards that are randomly entering the system.
Then the loader will cycle, causing one board at a time to be placed onto a
chain that has lugs affixed at a specific spacing. As the board moves with
15 the fixed lug chain, it will pass through a specific area known as the data
entry zone. As the board moves through the data entry zone, the trimmer
operator must read the grader's chalk marks and input this information into
the trimmer and sorting control system. The fixed lug chain is a continu-
ously moving chain and, therefore, the operator has only a limited (based on
20 drive speed of the lug chain) time to make the entry. If the entry is
completed while the board is in the data zone, then when the board reaches
the trimmer the appropriate saws will cut the board to length. After being
cut to length, the board will be sorted (placed with other boards of similar
length and quality).
With most automatic trimming and sorting systems, the data
entry zone is at a location downstream of the lug loader and, of course,
upstream from the trimmer. The lug chain is set at a speed determined by
the supposed capability of the trimmer operator to view and then input the
data for each board. ~oth thc trim data and grade must be correctly
30 determined and then correctly input, all while the boards travel through the
data entry zone at a high rate. The lug loader continuously feeds boards to
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10545 2
open lugs on the lug chain and the operator must keep up with the flow past
the fixed data entry zone. Inherent in this state~f-the-art feeding and data
entry system is pressure on the trimmer operator. With boards moving past
at up to one per second, oftentimes a late entry is made with the
consequence bein8 that two boards can be mistrimmed and missorted; once a
board moves out of the entry zone and data entered, supposedly for it, it
will be trimmed and sorted according to the previous set while the next
board within the zone will have improper data entered for it. Then the
operator must "catch up" and oftentimes makes erroneous entries under the
pressure just to catch up.
In present systems, the trimmer operators try to compensate for
the inherent problem by looking at boards upstream from those in the data
entry zone in order to memorize the grade and trim marks and then attempt
to stay ahead by entering correct data when the particular board is in the
data entry zone based on the operator's sense of timing. Once the speed of
the lug chain is set, for example at sixty lugs per minute, then the lug loader
will kick boards from the upstream chain into each set of lugs sequentially
on a continuous basis. If the operator fails to make an entry, than at least
one board is erroneously handled and if the operator, as previously men-
tioned, is in a "catch up" mode, the errors can be compounded.
ln the past, if an operator came under such pressure that
significant cumulation errors were bein8 made, the only alternative was to
slow down the lug chain. This alternative is not a desirable one since overall
mill production is then lowered. Usually the trimmer operator would be
replaced. In short, the trimmer operator has an extremely stressful job, one
that is improved significantly by the present invention.
Accordingly, from the foregoing, one object of the invention is
to offer a trimmer operator more flexibility in data entry.
Another object is to reduce the number of mistrimmed and
missorted boards coming from the trimmer.
Yet a further object is to reduce the mental pressure and fatigue
on the operator.
Still a further object is to provide a surge monitoring capacity
through a memory means.
These and many additional objects will become more apparent
upon reading the detailed description in combination with the drawing.
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10545 3
SUMMARY OF THE INVENTION
Briefly stated, the present invention is practiced in one form by
a trimmer feeding and data entry system having a lug loader feeding
individual boards to a lug chain. Boards will not be transferred until after
5 the trim and grade data has been entered into a programmable logic
controller or other suitable control means. The control means has a first-in,
first~ut memory means whereby the data for a number of boards can be
stored and then output at the appropriate time to activate selected trim
saws and sorting bin means.
DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic block diagram depicting the improved
trimmer feeding, data entry and control system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the figure, the feeding and transport system is
substantially state-of-the-art equipment and will be well understood by
those skilled in the art. Briefly, a smooth chain 10 will bring individual
boards, each indicated at 12, from the grading station (not shown) with the
near end of each board having the trim and grade marks on the top surface.
The boards come at a rate whereby they tend to back up when stopped at
the lug loader 14. A suitable hold down member 16 serves to maintain each
board in its proper orientation at the lug loader. When each board 12 is just
upstream from lug loader 14, it is stopped and held until the trim and grade
data is entered into the control system. The data entry zone 18 is,
therefore, upstream from the lug chain 20 and the boards are examined and
data entered while they are at rest rather than traveling. The operator's
location will be substantially adjacent entry zone 18 or at least clearly
visible from the location. By being adjacent zone 18, not only can the
boards be observed, but if boards 12 become stuck or otherwise a problem,
the operator can quickly correct the error.
Lug chain 20 is also typical in that a plurality of laterally spaced
individual lugs 22 are mounted on the chain and are uniformly spaced apart
in the longitudinal direction or the direction of travel of the boards. An
encoder 24 is a part of lug chain 20 and may be of any suitable type, such as
a shaft encoder, for tracking each lug position. Between the infeed and
outfeed ends of lug chain 20 are the trim saws, one of which is depicted
graphically at 26. Saws 26 are also state of the art and are mounted in a
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10545 4
suitable frame means so each can be lowered into the path of the traveling
boards upon being activated. The boards 12 are even ended so the saws are
all located with respect to a predetermined lateral distance from one end of
each board~ thereby providing for accurately located trim cuts.
The lug loader 14, as is well known, is a mechanical device that
moves one board 12 at a time from smooth chain 10 to lug chain 20. The
cycle of lug loader 14 is controlled by a cam and follower (not shown) that
time the feed of boards 12 between lugs 22 of lug chain 20. Cycling of the
loader 14 can be interrupted by activating a solenoid (not shown) that
removes the cam follower.
The trimmer operator has before him for inputting data into the
saw control and sorting system an operators' panel 28 having a plurality of
touch keys 30 to generate signals indicative of his decisions with respect to
which saws to activate and where the particular board will be deposited
according to its grade. As each board 12 is stopped ahead of lug loader 14
at data entry zone 18 awaiting feed onto lug chain 20, the operator observes
the board and inputs data via keys 30. As the data is entered, signals flow
via line 32 to a programmable logic controller 34 or other suitable data
; processing and control device, such as the "Modicon 384 Programmable
20 Logic Controller." Also flowing into controller 34 are signals via line 36
from encoder 24. As the grade and trim data is entered, it is first stored in
position one of a typical first-in, first-out memory unit 38, with the next
data for the next board in line going into position two and the next data for
the third board waiting at lug loader 14 within entry zone 18 going into
25 position three. Additional positions could be provided in memory unit 38 if
desired. If data exists in position one, then the lug loaders cam and follower
are engaged enabling the first board in line at loader 14 to be loaded into
the next set of lugs 22. Lug chain 20 is set to travel at a constant relatively
high rate of speed. If data is in position two of the memory unit, the second
30 board (although since the preceding board has left, it will in fact be first in
line) will then be immediately kicked into the next incoming set of lugs 22
and the same with position three for the next board. Each loader enabling
signal is sent to lug loader 14 via line 40.
Within controller 34 is a typical shift register unit 42 which
35 accepts data from memory unit 38 and is transferred from one position (A
through J corresponding to the lugs along the top run of lug chain 20) to the
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next by the signals received from encoder 24 via line 36. The output signals
from shift register 42 serve to control the saws and the sorting system (not
shown).
It is important to note that while the lug chain 20 travels at a
5 continuous high speed, the data is entered into the control system at a rate
determined by the operator and not solely by the machine. The present
invention provides more flexibility to the operator in his decision making
and data entry, thereby reducing mistakes and actually increasing produc-
tion through the trim and sorting system.
It will thus be appreciated that a significantly improved feeding
and data entry system for a lumber trimmer has been disclosed that is a
great advance over the state of the art. It is intended that all obvious
modifications to the preferred embodiment, as well as the preferred
embodiment, be included within the scope of the appended claims.
