Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: BOARD E`EEDER FOR LUMBER HANDLING SYSTEMS
The present invention relates to lumber handling ap-
paratus in which boards are moved successively from a single
feed station to a plurality spaced delivery station.
Handling of boards, especially small elongated boards
or "stickers" that are used for spacing layers of lumber apart
in a stack, is a difficult task. This is especially true where
the "stickers" are warped or twisted. Some positive gripping
action must be provided if the stickers are to be moved auto-
matically from one location to anotherl as when successive
stickers are to be moved from a feed conveyor in an orderly man~
ner onto a delivery conveyor.
U. S. patent Mo. 3~904/044~ granted to Sidney L. Lunden on
September 9, 1975, discloses a lumber stacking apparatus that
makes use of a sticker pla~ing mechanism where successive stick-
ers are delivered from a feed conveyor to a delivery conveyor.
The stickers are lifted or moved by engagement of single side
sur~aces. The sticker handling device operates well on straight
stickers, but i9 not ef~ective with twisted or warped stickers.
The present invention operates well even with warped,
twisted stickers by gripping the successive stickers along op-
posed side surfaces as they move to shi~t the successive stick-
ers from a feed station over a stationary stop to a delivey
station. The stickers are gripped while on the feed conveyor
and the grip isnlt released until the sticker has been moved
to the delivery conveyor.
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Fig. 1 is a fragmented diagrammatic side ~iew illus-
trating the present mechanism;
Fig. 2 is a pictorial vie~ of the linkage mechanism
and associated members of the present invention;
Fig. 3 is an enlarged detail view of a sticker gripped
between two clamp members of the present invention;
Figs. ~ through 7 are schematic representations of
the operational sequence involved with the present invention;
and
Fig. 8 is a diagrammatic representation of the paths
followed by the sticker gripping members of the present invention.
A feeder embodying a preferred form of the present
invention is indicated in the accompanying drawings by the
reference numeral 10. The present feeder 10 is to be used in
lumber handling systems for feeding a board 11 from a feed sta-
tion 12 to a delivery station 13.
For purposes of this application, the term "board"
is to be taken broadly as meaning any elongated wood member hav-
ing opposed elongated parallel side surfaces. The "boards" ll
shown in the drawings (Figs. 1 and 3) include elongated top side
surfaces 15 and parallel elongated bottom side surfaces 16.
A "sticker" is a small board that is used primarily
in the lumber industry. Thus the term "sticker" will be used
in this application interchangeably with "board" and referred
to with the same reference number.
The present feeder 10 has broad application to many
areas of the lumber handling industry but finds particularly
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beneficial use in conjunction with lumber stacking machines for
the purpose of delivering "stickers" ~rom a~hopper and feed con-
veyor 17 (Fi~. 13 at the f~ed station 12 to a delivery conveyor
18 at the delivery sta.tion 13. Only a portion of the hopper
and feed conveyor assembly 17 is shown, along with a portion
o:E a delivery conveyor 18. Such mechanisms are shown i.n sub-
stantially more detail by United States Patent 3,904,044.
The present feeder 10 may inclu~e a supportive frame-
work 20 that may be separate from or integral with the adjacent
framework of the remaining lumber handling system. The frame-
work 20 defines the feed station 12 preferably along a horizontal
plane, with the delivery station 13 (delivery conveyor 18) situated
along a horizontal plane spaced ~rom the feed station by a
stationary stop 23. The stop 23 may be provided as a simple
upright dog ~ixed to the framework 20.- It is preferable also
that the two stations be situated at the same or similar eleva-
tions~
The stickers 11 are delivered in a direction trans-
verse to their lengths across the feed conveyor 17 to the stop
23. The ~eed conveyor 17 may be operated constantly to con-
tinuously urge t~e successive stickers forwardly against the
stop. A single sticker will therefore always be present at the
feed station so long as there remains any stickers on the feed
conveyor 17.
The present feeder 10 includes a first clamp means
24 and a second clamp means 25 -that are operated in coordina-
tion with each other to: (1) grip successive stickers at the
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feed station; (2) move them over the stop to the delivery sta-
tion; and subsequently ~3) release the stickers at the delivery
station. The first clamp means engages the top side surfaces
15 and reciprocates in an arcuate path 57 (Fig. 8) ~etween the
delivery and feed stations. The second clamp means 25 engages
the bottom side surfaces 16 of the boards and moves in a closed
arcuate path 58 from one station to the other. A linkage means
27 is provided to move the clamps in unison between the stations
while a drive means 28 (Fi~. 1) operates the linkage means to
cause movement of the two clamp means.
The first clamp means 24 is shown in substantial de-
tail by ~igs. 2 and 3. The first clamp means includes an elon-
gated cross bar 30 that is positioned above the hopper feed con-
veyor 17 and delivery conveyor 18. It extends longitudinally
with respect to the stickers on the conveyors and projects be-
yond opposite ends t~ereof. The cross bar 30 is mounted to a
pair of rocker arms 31 that extend between opposed ends of the
cross bar and the framework 20.
A pivot shaft 32 extends between rocker arms 31 and
framework 20 to define a fixed horizontal pivot axis for the
first clamp means 24 that is preferably parallel to the stickers
on the feed conveyor 17. The pivot axis defined by shaft 32
is preferably sit~ated directly below the stop 23 so the arcuate
path 57 defined by the cross bar 30 will assume the configura-
tion shown in Fig. 8. Specifically, the opposite ends of the
reciprocating path are situated closely adjacent to the top sur~
faces of the stickers at the two s-tations. The path 57 extends
above the stop 23 between the two stations 12, 13.
Connecting links 34 are provided -to join the first
clamp means 24 to the second clamp means 25. The links 34 are
mounted by pins 35 -to upper ends of the rocker arms 31. Oppo-
site ends of the connecting links 34 are connected to a shaft
36 that mounts the links to the second clamp means 25. The pins
35 and shaft 36 define horizontal pivot axes that are parallel
to the axis of shaft 32. Links 34 are included as part of the
linkage means 27 in that they transmi~ motion from the second
clamp means 25, directly to the first clamp means 24. In addi-
tion, the links 34 serve to control the angular orientation of
the arcuate reciprocating path of the first clamp means with
respect to the function of the first clamp means. The links
34 also guarantee simultaneous motion of the two clamp means
24, 25.
A sprin~ means 37 (Fig. 3) is provided on the cross
~ar 30 for yieldably engaging the top surfaces 15 of succes-
sive stickers. The spring means 37, it may be noted, can be
provided on either or ~oth of the clamp means 24 or 25 for use
generally in ~iasing an engaged sticker against the opposite
clamp means. The spring means 37 is preferably a form of "leaf"
spring having a free end for resiliently engaging the top sur~
face of the s~icker to firmly grip the sticker.
The second clamp means 25 is provided for the purpose
of: (1) engaging the bottom surfaces 16 of the individual stick-
er; (2) lifting the sticker against the first clamp means; (3)
together with clamp means 24~ moving the stickers over the stop
23; and t4) releasing the sticker onto the delivery conveyor.
The second clamp means 25 includes a pair of clamp
supports 40 provided as integral parts of substantially hori-
zontal clamp arms 41. The clamp supports 40 and clamp arms 41
are mounted to the frame by the linkage means 27 to move in a
closed arcuate path 58 as shown by Fig. 8 The clamp supports
40 move upwardly at the feed station to engage the bottom sur-
face of a sticker that is positioned against the stop 23. The
supports 40 then continue on upwardly, lifting the sticker into
engagement with the 9pring means 37 on the cross bar 30. The
sticker is therefore positively gripped while being moved from
the feed station to the delivery station.
The linkage means 27 has already been described to
a limited extent. It includes the connecting links 34 and rock-
er arms 31. In addition, the linkage means includes a pair of
crank arms 45 that are pivotably joined to forward ends of the
clamp arms 41 by pivot pins 47. The crank arms 45, in turn,
are rotatably mounted on a crank shaft 48 below the feed and
delivery station. The sha-ft 48 is rotated by the drive means
28 to rotate the crank arms 3~0 about the crank shaft axis.
The crank shaft axis, as well as the axis of the pins 47 are
parallel to the rocker arm pivot axis.
Rearward ends of the clamp arms ~1 are connected to
the frame 20 by rocker links 51. The links 51 are attached by
pivot pins 52 to the clamp arms 41. Opposite ends of the rocker
links 51 are connected at pivots ~3 to the framework defining
a fixed horizontal axis. The distance between the pivots 53
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and pins 52 represents a radius about which the rearward end
of the clamp arms 41 are free to travel about the fixed hori-
zontal axis of pivots 53.
Rotation o~ the crank arms ~5 about the shaft axis
will cause rocking motion of the links 51. The combined motion
(the rocking motion of the rearward end of clamp arms ~1 about
the fixed horizontal axis along with the circular motion of the
forward clamp arm ends) produce the substantially eliptical path
58 made by the clamp supports 40 (Fig. 8). Such path 58 is so
arranged that approximately one half of the path (o-f the clamp
brackets) is situated above the working surfaces of the feed
and delivery conveyors. The bottom half of the arcuate path
is situated below the conveyors and in a direction returning
to a Eeed station.
Drive means 28 includes a chain linkage 50 connecting
the crank shaft ~8 to a drive mechanism 54. This mechanism may
be operated independently or dependen-tly upon drive m~chan~sms
for the associated machinery. It may also be operated intermit-
tently by appropriate controls to ~acilitate spacing of successive
stickers along the delivery conveyor 18. Such spacing control
can be manually or automatically controlled. Two alternate methods
showing sticker spacing may be found in the above referenced
patent.
Prior to operation, a load of stickers is delivered
to the feed station 12. The feed conveyor 17 may operate con-
tinuously, sliding under the stickers when they come into engage-
ment and halt the stickers against the stop 23. ThereEore, when
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one sticker is lifted from engagement with the stop, -the re-
maining stickers will index forwardly with the succeeding skicker
moving into engagement with the stop.
A sticker at the feed station is situated elevational-
ly between the two clamp means 2~ and 25. Upon actuation of
the drive means, the clamp means 24, 25 will be moved together
simultaneously clamping -the sticker and lifting it up and over
the stop 23. The sticker 11 is then lowered onto the delivery
conveyor where it is released. The two clamp means 24, 25 then
separate from one another and move back to their original posi-
tion at the f eed station.
The first and second clamp means move simultaneously,
with the top or first clamp means 24 moving in the reciprocating,
arcuate path 57 in Fig. 8. The bottom or second clamp means
25 moves through the closed curve 58. An upper portion 59 of
the curve 58 is at an elevation higher than the surfaces of the
conveyors 17 and 18. Furthermore, the peak elevation is higher
than the stop 23 so t~e sticker can be lifted upwardl~ off the
feed conveyor, over the stop, and deposited onto the delivery
conveyor.
The upper curved portion 59 is complementary to the
arc 57. The curved portion 59 is more sharply arcuate at its
ends than the arcuate path 57 of the first clamp means. The
second clamp means 25 will move sharply upward at the beginning
of its forward stroke, lifting the sticker into engagement with
the first clamp means beore it moves over the stop (Fig. 5).
Similarly, the second clamp means will descend sharply at the
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end of its forward stroke to release the gripping force
against the sticker and lower the sticker on-to the delivery
conveyor (Fig. 6~. A lower curved portion 60 of curve 58 is
provided in the return path of the clamp means 25 and is below
the stations to clear the stickers and frame as it returns.
The positive gripping of successive stickers between
the two clamp means assures that even badly warped or twisted
stickers can be moved from one station to the other. Other varia~
tions such as minor size differential among stickers is accomo-
dated by the above described device.
The above description and attached drawings are given
by way of example to set forth a preferred form of the present
invention. Additional forms may fall within the scope of the
following claims, which more precisely define my invention.
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