Патент USA US3438628

April 15, 1969 -
‘
R, L, BmDGES ET AL
3,438,623
AUTOMATIC UNSTACKER FOR VENEER AND OTHER MATERIALS
Filed Feb‘. 27, 1967
Sheet
,
/
of 2
INVENTORS
3%? 2.
ROBERT L. BRIDGES’
BY EARL D. HAS’ENM/YME
zéagg, m k
(
i?gww-w
April ‘15, 1969
‘R. L. BRlDGEs ET AL
3,438,623
AUTOMATIC UNSTACKER FOR VENEER AND OTHER MATERIALS
Filed Feb. 27. 1967
Sheet
2
of2
@mIEF.
IN VENTO‘R3
ROBERT 1.. [SW/D653
EARL D. H/lSE/YlW/YKZE
United States Patent Office
1
2
a conventional X-frame lift table 4 having suitable pow
ered means to raise and lower the table. A photoelectric
cell 5 operatively connected to the powered means of
the lift table, is positioned adjacent the lift table as shown.
As long as the light beam is unbroken the lift table raises
the stack of veneer. Positioned above the lift table and
3,438,623
AUTOMATIC UNSTACKER FOR VENEER
AND OTHER MATERIALS
Robert L. Bridges, Kelso, and Earl D. Hasenwinkle, Long
view, Wash., assignors to Weyerhaeuser Company, Ta
coma, Wash., a corporation of Washington
Filed Feb. 27, 1967, Ser. No. 618,668
Int. Cl. B65h 3/06, 5/06
US. Cl. 271-—39
3,438,623
Patented Apr. 15, 1969
the stack of material to be transferred are a plurality of
arms 6 mounted on a main support shaft 7. Clutches 8,
4 Claims
either magnetic or other, are mounted on the arms 6
10 either above or below the arms. On the ends of the arms
overhanging the material to be transferred are attached
driving discs 27. Sprockets 11 are mounted within the
arms 6 and chains 12 connect the sprockets 11 and 13.
The disclosure shows a method and machine for un
A motor 14, or other suitable means, drives the main sup
stacking veneer or other sheet materials and transferring
them to a conveyor. The machine is operated by raising a 15 port shaft 7 which, in turn, is connected. to the clutches 8
by chains and sprockets 15, 16, and 17, and shafts 9.
stack of material supported on a powered lift table‘ to the
The outputs of the clutches on which sprockets 18 are
point where the surface layer of material is engageable
mounted are connected to sprockets 20 by chains 19. On
with a series of drive discs. These provide high horizontal
the ends of arms 6 opposite the driving ‘discs 27, counter
friction with the material yet exert a low vertical pressure.
ABSTRACT OF THE DISCLOSURE
This enables the separation of the layers of material and 20 balances 21 may be mounted as shown to control the
downward weight of the arms on the material to be trans
ferred. Above each of the arms and attached to the frame
1 are a series of rheostats 22 having ladder chain sprockets
23
attached to each of the shafts of the rheostats. Chains
Background of the invention
25 24, attached to the arms 6 and over sprockets 23, have
In the manufacture of plywood and other laminated
weights 25 attached to their free end. The rheostats are
materials it has been a conventional practice to unstack
electrically connected to the clutches for varying the volt
veneer by hand for placement on a conveyor; however,
age delivered to the clutches. A conventional conveyor 26
with high-speed automated systems, manual unstacking of
is situated at right angles to the .unstacker for further
veneer is not practical or efficient. Although several means 30 transferring the separate pieces of core to equipment (not
are known for unstacking planar materials, they are not
shown). The drive discs 27 depicted in the drawing are a
transferal thereof to a conveyor with a minimum of mul
tiple feeding.
readily adaptable to unstacking veneer layer by layer and
series of serrated discs, typically saw blades, however, any
transferring it to a conveyor because of the various sizes
con?guration disc capable of exerting ‘a high horizontal
and uneven nature of the veneer. The use of friction belts,
force on the top layer of material to be transferred may
for example, to peel off the surface layer of a stack of 35 be used.
veneer has not worked to any extent because, if suf?cient
In actual operation a stack of core is transferred onto
pressure is applied between the belts and the veneer sur
the X-lift and raised to the drive discs. The photocell
face to drive the veneer from the pile, the downward pres
situated adjacent to the lift controls the level of the
sure of the belts on the stack results in multiple feeding.
veneer. The drive discs engage the veneer and move it a
The use of a gating device in conjunction with the friction 40 few inches into the opposed rotating rolls which in turn
belts to prevent multiple feeding is unworkable because of
rapidly transfer the pieces onto the conveyor. The speed
ratio of the rolls to the driving discs, for example, may
the unevenness of the veneer to be unstacked.
range from 4:1 to 8:1.
Summary
In order to prevent multiple feeding of the material
This invention has for its primary purpose a method 45 it is essential that a signi?cantly high force be exerted
and means to unstack planar material and deliver it di
on the surface layer of material in a horizontal direction
rectly to a conveyor. Although this invention is applicable
and that a minimum of vertical pressure be exerted on
to unstacking of many different planar materials it is most
the stack of material. This is achieved by (1) control
useful in unstacking core veneer for automated plywood
of the height to which the stack of material is raised by
manufacture such as in conjunction with the wet-web 50 the lift table on which it is supported, (2) the weight
production of plywood described in US. Patent No.
of the driving discs resting on the surface layer of ma
3,247,042. The machine of this invention allows unstack
terial, and (3) the driving force exerted by the discs
ing of material with a minimum of multiple feeding by
on the surface layer of material. The height of the
use of driving discs having high horizontal friction with
the material but with minimum lvertical pressure.
Brief description of the drawings
An embodiment of the equipment is illustrated in the
drawings wherein:
FIGURE 1 is an elevation of the feed end of the ma
chine,
55
stack of material is controlled by the photoelectric cell.
The weight of the driving discs on the stack of material
is controlled and varied by the counterweight attached
to the ends of the arms opposite the driving discs. The
driving force applied to the driving discs through the
clutches is controlled and may be varied through the
60 rheostats. As the discs on the arms are lowered, the chain
and sprocket linkages over the rheostats turn the rheo
stats and increase the resistance in the clutch electrical
machine, and
circuits which, in turn, produce a lower voltage to the
FIGURE 3 is a sectional view taken along broken sec
clutches and results in a lower driving force at the driv
tion line 3-3 of FIGURE 1.
65 ing discs. As the arms are moved upward the process
is reversed and an increasing driving force results until
Detailed description of the drawings
sufficient force is attained to move the surface layer of
Referring to the drawings in detail, 1 designates the
material into the opposed rolls.
overall frame of the machine. A pair of opposed rolls 2
This machine is particularly well adapted to unstack
are attached to the frame as shown and are driven by 70 ing and transferring core veneer which is normally clipped
suitable means (not shown). The stack of planar material
in varying widths and standard lengths or uniform widths
3, which may be veneer or other material, is supported on
and standard lengths. The former is usually designated
FIGURE 2 is an elevation of the discharge end of the
3
3,438,623
“random” core and is stacked into a roughly square pack
age with the outside edges of the load uniform and the
inner portions varying and often interlaced with other
core veneer. The latter is designated “tailor made” and
normally consists of two uniform piles stacked side by
4
(g) means operatively connected to the clutches for
varying the power output of each of the clutches
r
in response to the upward and downward move
ment of the respective arm members.
2. A machine according to claim 1 wherein the de
livery means comprises a series of serrated discs.
side to form roughly a square package. The machine of
this invention is able to unstack either “random” or “tailor
3. A machine for unstacking and transferring a stack
made” core of commonly used thicknesses.
of planar material directly to a conveyor which com
The apparatus of this invention can also be operated
prises:
without the rheostat mechanism as described to control 10
(a) means for supporting a stack of material having a
the force delivered to the driving disc. In operating the
surface layer of material to be transferred,
machine in this manner the force necessary to transfer
(b) circular feeding discs mounted for movement rela
the veneer to the conveyor is controlled by the level which
tive to the stack surface and positioned normal
the veneer is raised and the downward Weight of the driv
to and engageable with the surface layer of the
ing discs on the surface layer of veneer. The driving force
stack of material,
transmitted to the driving discs through the clutches in
(c) means for moving the stack surface relative to
this instance remains constant.
the feed means, and
In summary, the method and means of this invention
(d) drive means operatively connected to the circular
provide a relatively e?‘icient and inexpensive way of
feeding discs comprising
transferring material, particularly core veneer, directly 20
(1) a series of clutches operatively connected to
to a conveyor at speeds compatible with the machine’s
each of the circular feeding discs,
use in conjunction with automated plywood systems.
(2) power means operatively connected to the
Having described my invention, what I claim is:
clutches to drive the clutches, and
1. A machine for unstacking and transferring a stack
(3) means for varying the power output of the
of wood veneer directly to a conveyor which comprises
clutches to the respective feeding discs to con
in combination:
trol
the driving force applied to each of the
(a) a lift table supporting a stack having a surface
discs, the power output of the clutches increas~
layer of veneer to be transferred,
ing on movement of the feeding discs in an up
(b) powered means operatively connected to the lift
ward direction and decreasing on movement of
table to raise and lower the table surface supporting 30
the feeding discs in a downward direction.
the stack of veneer,
(0) height sensing means positioned adjacent to and
4. A machine according to claim 3 wherein the means
operatively connected with the lift table on which
for varying the power output of the clutches comprises
the veneer is stacked so as to control the level of
rheostats operatively connected to each of the clutches
the veneer,
and arm members.
((1) feed means positioned adjacent to and engageable
with the surface layer of the veneer comprising:
(1) a shaft normal to the direction of movement
of the veneer,
(2) a plurality of arm members mounted rotatably 40
on the shaft parallel to the direction in which
the veneer is to be moved, and
(3) delivery means for engaging the veneer ro
tatably mounted on the ends of the arms over
References Cited
UNITED STATES PATENTS
2,571,942
2,819,078
10/1951
1/ 1958
Properzi __________ __ 271—-36
Durand ___________ __ 271—39
3,021,136
2/1962
Fox ______________ __ 271-36
3,062,534
11/1962
Benson et a1 ________ __ 271—36
hanging the veneer,
45
FOREIGN PATENTS
(e) magnetic clutches operatively connected to the de—
551,629
10/1956
Belgium.
livery means,
(f) power means operatively connected to the magnetic
RICHARD E. AEGERTER, Primary Examiner".
clutches to drive the clutches, and