Conveyors: power-driven – Conveyor for changing attitude of item relative to conveyed... – By conveying randomly faced items and turning items to...
Reexamination Certificate
2001-05-30
2003-05-27
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor for changing attitude of item relative to conveyed...
By conveying randomly faced items and turning items to...
C198S406000, C198S400000
Reexamination Certificate
active
06568523
ABSTRACT:
Inventor
Stibbard; James S.
Citizenship
Canadian
Address
Box 2387, High Prairie, Alberta, Canada TOG 1E0
Telephone
780-523-3182
Email
stibbard@telusplanet.net
Assignee
Stibbard; James S. (High Prairie, Alberta)
REFERENCES CITED
6,189,682
Feb. 20, 2001
Hill
198/718
5,617,910
Apr. 8, 1997
Hill
144/356
4,429,784
Feb. 7, 1984
Cromeens
198/744
4,246,943
Jan. 27, 1981
Cromeens
144/245
4,039,108
Aug. 2, 1977
Hahn et al.
226/171
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
Finger jointing machines are used to mill joints in the ends of random lengths of lumber, hereafter referred to as “blocks”. Glue is applied to the joints and the blocks are pressed together to form longer pieces of lumber. This is an oversimplification of a precise, complicated process known as finger jointing, but the focus of this invention is the accurate feeding of finger joint machines with blocks, not the process of finger jointing blocks.
This invention relates generally to an apparatus that requires no human operator and that accepts a random and haphazard delivery of blocks from a supply conveying means, ensures that every block has an acceptable moisture content and delivers a consistent, correctly aligned and correctly orientated supply of blocks at precise intervals to the finger joint machine's lug or slat chain at any lineal speed that is determined by that finger joint machine.
This invention applies to finger joint machines which use either a chain with lugs spaced at regular intervals thereon or a plurality of chains connected by slats at regular intervals to push a block through the said machine's shaper head or heads. The former type of finger joint machine is referred to as a lug chain finger joint machine and the latter is known as a slat chain finger joint machine. The phrase “lug chain” includes the “finger joint lug chain” and the “finger joint slat chain”, but the phrase “finger joint slat chain” may be used herein when necessary. Lugs or slats attached to the lug chain are referred to as “lugs” herein, ignoring the difference between a lug and a slat. The means to supply either type of finger jointing machine with raw material is known as a lug loader by those knowledgeable in the art. Placing a block ahead of a lug is referred to as placing a block “on lug” herein. For clarity, the longitudinal left hand end of any apparatus is defined herein as the infeed, where blocks are deposited to be eventually fed to the finger joint machine. The right hand end of the same apparatus is defined as the outfeed where blocks are deposited on the finger joint machine. The direction of travel is assumed herein to be from left to right and upstream refers toward the infeed and downstream refers toward the outfeed. The words “sprocket” and “chain” may sometimes refer to a multiplicity of sprockets and/or chains, but the singular is generally used.
Historically, finger joint machines were supplied with blocks manually.
FIG. 1
illustrates the steps required to place blocks on a lug chain manually. A supply means
1
deposits blocks
2
on an accumulation table
4
, where a person
3
picks up a block
2
, aligns and places it on the finger joint machine's
6
lug chain
7
. Human dexterity became incapable of placing a block in each lug
5
of the lug chain
7
as lug speed and operating speed increased. Empty lugs represent lost production, increased costs and less profit. Workers also suffer injuries while placing blocks manually on lug, thereby increasing production costs with production down time, employee sick leave, various forms of compensation, new operator training and rehabilitation of the injured worker.
Mechanical lug loaders were invented to supplement or replace manual lug loading and work with varying degrees of success. Some individuals, such as Hill, U.S. Pat. No. 6,189,682, U.S. Pat. No. 5,617,910, Cromeen, U.S. Pat. No. 4,429,784, U.S. Pat. No. 4,246,943, Hahn et al., U.S. Pat. No. 4,039,108, and others, were awarded patents for their inventions. Others put their inventions to work in their own manufacturing operations without patent protection.
Lug loaders have generally comprised four separate means to accomplish the task of placing blocks on lug: a supply means, a powered accumulation means, a control means and a powered transfer means.
FIG. 2
illustrates the steps required to load a finger joint machine's lug chain
7
with blocks
2
using a prior art lug loader (sensors and electronic means required to control the prior art lug loader have not been shown).
A supply means
1
, which may be a vibrating conveyor, belt conveyor, or some other means, deposits blocks
2
in a haphazard and random fashion on an accumulation means
9
, where a person
3
manually picks up a block
2
, orientates it in a side-by-side, parallel manner with other blocks
2
with its widest face down and one of its ends aligned to a fence
8
, which represents a datum line that continues to the finger joint machine's own fence. A fence
8
may be understood as an obstruction that runs longitudinally along one side of the accumulation means
9
from its infeed to its outfeed in a more or less straight line. Workers must ensure that blocks
2
always maintain contact with the fence
8
and that blocks
2
remain at right angles to the fence
8
, because block ends may not be milled correctly by the finger joint machine
6
, if they are placed on the lug chain
7
at some distance from the fence
8
.
The block is then moved under the powered brush hold down
12
on the accumulation means
9
and is pushed in the direction of travel until it is stopped at the control means
10
. The control means
10
releases blocks
2
onto the transfer means
11
at intervals synchronized with the lugs
5
. Synchronization may be achieved by electrical or mechanical means and various means, such as levers or pinch rolls employing pressure cylinder means, are used to release blocks from the accumulation means
9
to the transfer means
11
.
The transfer means
11
, that bridges the gap between the accumulation means
10
and the lug chain
7
, is often comprised of two features: a form of table that blocks lie on and an overhead conveying means. The table generally has a low coefficient of friction and may be comprised of sheet metal, skate wheels, or synthetic materials such as UHMW, which encourage the overhead conveying means
12
to push the block
2
across the transfer table
11
smoothly. The overhead conveying means
12
, which may be comprised of a powered brush hold down or a powered, narrow polyethylene belt conveyor, applies pressure against the block
2
and pushes it across the transfer table
11
. Overhead conveying means
12
usually require precise adjustment for block thickness to work satisfactorily, otherwise malfunctions may occur.
The transfer means
11
, assisted by the powered brush hold down
12
, deposits the blocks
2
on the lug chain
7
.
Problems often occur when block lengths vary significantly, for example 5½ ″ to 55″, because the longer length blocks tend to push around the shorter blocks on the accumulation table and under the powered hold down. Problems also occur on the transfer table because one end of a block is controlled better than the other. In each case, this causes one end of the block to lag behind the other, which may cause the block to move away from the right angled orientation required by the finger joint machine. Various means, such as powered hold down brushes, have been developed to remedy this problem, with limited success, and manual intervention is usually required to ensure satisfactory block alignment for the control means.
A finger joint machine may tolerate some poor orientation and misalignment, but mismanufacture and/or damage may occur if blocks become seriously disturbed, especially if a block jams between the finger joint machine's lugs.
Lug loading means do not normally include a means to determine block moisture content and a means
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