Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to an improvement ln machines
for forming tiers of cartons in a predetermined pattern and
loading or stacking successive tiers on a pallet to be trans- :
ported from the machine. In one aspect this invention relates
5 to an improved machine wherein the tiers are formed con- -
tinuously and placed on the pallet or preceding tiers and
when a pallet is loaded it is moved out of the elevator but ~-
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an empty pallet is mechanically inserted into the stream of
tiers at the top of the elevator between a loaded pallet and
the tier-forming stationary plate.
The prior art is replete with devices for placing
cartons upon pallets to load the pallets automatically.
In many of the known prior art patents it is necessary
to utilize elevator means for lifting successive tiers of
cartonson to a pallet to produce a stack of cartons on said
pallet~ It has been found however to be advantageous to form
the tiers of cartons and to move the same along the continued
path to a position above the supporting pallet and then to
lower the cartons onto the pallet and onto preceding tiers to
stack a pallet with several tiers of cartons. The pallet is
lowered after each tier is placed thereon to a position to
receive a suhsequent tier. After the pallet is completely
loaded the same is moved out of the elevator and a second pallet
is inserted to receive the next tier of-cartons. If it is
necessary to wait for the loaded pallet to be removed from
the elevator and for the elevator to receive a pallet and -
raise the pallet to a loading position the continued stream
of cartons to the accumulator forming the tiers is interrupted~
` It is thus advantageous to insert the empty pallets at the
top of the elevator receiving the tiers.
One prior patent, U.S.A. Letters Patent No.
2,815,870, issued December 10, 1957 to Herman Laub discloses
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an apparatus wherein the pallets are placed at the upper por-
tion of the stacking column to receive cases placed thereon
avoiding the necessity of the pallet being placed on the
elevator and elevated to receive the first layer. The machine
construction disclosed in patent No. 2,815,870, however has
the tier forming mechanism positioned directly ove~ the
elevator making it necessary for the flow of cartons to be
interrupted as each row is formed and after each tier is
formed. Further, the elevator structure utilized flight bars
extending between endless chains such that each elevator
comprised a pair of spaced flight bars which would be bridged
by a pallet. In this construction the pallets have to be in
nearly excellent condition without splintered edges or corners
such that they could be supported only at opposite edges and
carry the full load or stack placed thereon~ The disadvantages
of the prior art devices are thus the necessary interruption
of carton flow and the lack of complete support beneath the
pallet as the height of the stack increases. The first slows
the production rate and the second means that many pallets
become rejects for fear they will not be adequate supports
in the loading elevator.
It is an ob~ect of the present invention to
provide a "palletizer" or a pallet loading machine which
will form tiers of cartons and stack the same on the pallet
without interrupting the flow of cartons from a packaging,
boxing or casing machine~ The pallet loading machine of the
present invention provides a novel pallet inserting mechan-
ism which supports the pallet in two loading positions prior
to the same being placed upon the elevator such that continued
movement of cases and tiers of cases is not interrupted.
The tiers are stacked by being wiped off a stationary plate
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onto a moving plate which is then stripped from beneath the
cartons placing them in the stack.
The pallet loading device of the present invention
comprises an in-feed conveyor which feeds cartons to a pri- ~ -
5 mary rotator or star wheel. The primary rotator is provided ~-
to receive an even number of cartons and position all of the `
cartons in a predetermined position for movement into the
tier-forming machine. The tier-forming machine receives
the cartons in two parallel paths, each path leading to a -
secondary rotator which may be raised out of the path or
which may engage and turn one or two cartons at a time to
place the cartons in a correct orientation to form the
required pattern of cartons in a tier, The secondary rotators --
are programmed and operate independently to rotate the cartons
and if it is desired not to rotate the cartons the secondary
rotators are moved vertically out of the path of the cartons. -
From the secondary rotators the cartons enter the tier-forming
: area~ The tier-forming area consists of powered rollers to
move the cartons, endless belts which converge to crowd
the cartons, and a number of air operated stops which are
properly located between the powered rollers of the roller
; conveyor to assist in forming the desired pattern for each
tier of cartons. From the tier-forming area the completed
tiers of cartons are conveyed in the loading area.
In the loading area the completed tiers are pushed
by successive flight on push bars extending between endless
chains from the powered roller conveyor onto a fixed transfer ~
plate~ Each push bar continues to move the tier across the ~ ~y
fixed transfer plate depositing the cartons onto a movable
stripping plate, moving with the push bar. The stripping
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plate receives the tier when it is poaitioned ahoYe the pallet
and the stripper plate is then retracted to a position beneath
the fixed plate and the push bar holds the cartons so the strip-
per plate will be stripped from beneath the cartons placing
them on the pallet. Upon the return of the stripper plate the
pallet is lowered with the tier of cartons. The stripper plate
is then beneath the transfer plate and another tier of cartons
is wiped from the fixed transfer plate onto the moving stripper
plate and the second tier is moved out over the elevator. When
the pallet is completely loaded it is lowered to the discharge
conveyor by the elevator and it is moved out of the stacking
chamber. The pallet is moved out of the stacking chamber on
a pair of guide rails during the receiprocatory movement of the
stripping plate into the area above the elevator with the next
tier. The empty pallet is supported by the guide rails and the
guide rails can be lowered to receive at least a second tier
of cartons allowing sufficient time for the elevator to return
to support the pallet across its entire area and to continue
lowering the pallet fixed amounts in the stacking chamber -
20 as the entire stack is completed to form a load. ~;
The palletizing machine constructed in accordance -
with the present invention comprises accumulator means for
accumulating cartons and forming a tier of said cartons, a
stationary smooth plate positioned adjacent said accumulator
means, advancing means for pushing a said tier of cartons
across at least a portion of said accumulator means and across
said stationary plate for moving a said tier of cartons onto
said stationary plate and off said stationary plate, Recipro~
cating plate means are movable in a plane generally parallel to
and closely spaced below said stationary plate from a position
beneath said stationary plate in a direction away from said
accumulator means for receiving a tier of cartons as it is '- `
moved off said stationary plate by said advancing means.
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Elevator means ad~acent said stationary plate support a
pallet to be loaded with successive tiers of cartons. In
this machine the cartons will move from the reciprocating plate
means onto a pallet on said elevator means upon return of said
reciprocating plate means to its position beneath the stationary
plate, and additional advancing means are provided for moving a
second tier of cartons onto said stationary plate. As the
pallets are loaded and removed from the elevator means, means -
are proyided for inserting empty pallets into the upper portion
of said elevator means simultaneously with the movement of said
reciprocating plate means from said position beneath said
stationary plate for positioning a pallet to receive at least
one tier of cartons while said elevator means is lowered to
a position to permit discharge of a loaded pallet. The means
for inserting empty pallets comprises conveyor means for in-
serting empty pallets seriatim ~eneath said stationary plate
and the plane of said reciprocating plate means, and movable
guide support bar means supported along the path of said
reciprocating plate means for raising a pallet off said
conveyor means to a position to be engaged by said recipro-
cating plate means for movement therewith to a position above
said elevator means and for supporting a said pallet upon
return of said reciprocating plate means and the tier of cartons
deposited thereon.
An illustrative embodiment of the present inven-
tion is described herein and shown in the accompanying drawing ;
~he~rein:
; Figure 1 is a schematic plan view of the pallet-
' izing area in a bottling, canning, or packaging plant dis-
closing the plan view of two pallet loading machines and pallet
conveyor constructed in accordance with the present invention;
Figure 2 is a fragmentary plan view of the tier-
forming section;
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Figure 3 is an elevational view of the tier-form-
ing section shown in Figure 2;
Figure 4 is a fragmentary longitudinal sectional
view of the loading station and the top portion of the
stacking chamber;
Figure 5 is a plan view of the loading section of ~- :
the machine shown in Figure 4;
Figure 6 is a fragmentary cross-sectional view
taken along the lines 6-6 of Figure 5; ~
Figure 7 is a fragmentary cross-sectional view - -
similar to that of Figure 6 showing the guide members in -~
an alternate position and appears on sheet 1 of the drawing;
Figure 8 is a cross-sectional view of the support
and drive means for the guide members; -~
Figure 9, 10, ll and 12 are schematic diagrams ~ ~ -
showing the operation of the loading station? Fig. 12 appears
:. on sheet 5 of the drawing; and
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Figure 13 is a graph of a timing chart indicating
the timing sequence of the operations of the loading station.
The pallet loading machine of the present
invention is adapted to be positioned at the end of a bottling,
canning or packaging machine which places articles in cartons,
which cartons are to be stacked on pallets for ready ship-
ment. The production requirement of the packaging machines
has increased to an extent that it is necessary to very
rapidly handle these cartons and place the cartons in tiers.
10 A machine which will handle at least 100 cartons per minute ~ -
and stack the cartons in a seven carton tier with tweleve
tiers per pallet provides equipment which will meet the
present packaging requirements. This is believed to be
fifteen to twenty cartons a minute faster than existing
15 machines for palletizing~
As illustrated in Figure 1 two pallet loading ~ -
machines generally designated lQ are positioned in a pallet-
izing area in parallel position~ The parallel positioning
of the palletizing machines conveniently reduces the number
20 of conveyors to those which are necessary to handle the empty
pallets necessary for each machine. The pallet-loading machine
10 comprises an in-feed conveyor 13 which feeds the cartons
from a packaging machine onto the powered roller conveyors of
the pallet-loading machine. Conveyor 13 may be a belt or
25 powered roller conveyor. The cartons moving along the conveyor
13 are moved in a lengthwise direction of a single file against
a primary star rotator 15 which catches two cartons at a time
and rotates the two cartons 90, separating the cartons and
discharging the cartons onto two roller conveyors 28, each
30 comprising a plurality of rollers with a true taper to separate
the two cartons to follow separate paths about an island
16. The conveyors 28 move the cartons to the tier-forming
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section~ generally designated 20, of the pallet loadln~
machine lO~ In the tier-forming section the cartons are con-
tinuously driven along the machine by powered rollers and
the separated cartons are first driven toward a set of
5 transversely spaced secondary rotators 21 and 22. The
secondary rotators are programmed such that they can turn
one or two cartons at a time and they are also powered to ~ -
be rapidly raised vertically out of the path of the cartons
if such is necessary to properly position the cartons to
10 form the required pattern of cartons in a given tier. As
the cartons pass the rotators 21 and 22 they engage a pair of
converging squeeze conveyors 24 or 25 which move the cartons
toward the center of a roller conveyor 29 in the tier-forming
section of the machines 10.
The cartons are always driven by the conventional
powered roller conveyors supported on the bed of the machine.
The cartons are moved into engagement with a number of air
operated stops 26 (see Fig. 4~ which are powered to be `
raised between certain rollers of the powered roller conveyor -
2Q 2~ StQpping the cartons to allow successive cartons or rows
of cartons to be positioned thereagainst forming the tiers.
As each row is formed it is then advanced along the machine by
dropping one stop to be caught by a succeeding stop until the : :
next row is formed by a sufficient number of cartons passing
- 25 through the secondary star wheels and feeding into the tier
from both sides of each row, A final stop 26 (Fig. 4)
indicates the tier is formed~ y
Once the tier is formed advancing means move said -~
tier across at least a portion of said accumulator and across
3Q said stationary plate. The tier i5 moved between sets of
transversely spaced sprocket wheels for a pair of endless
chains 30 between which extend flight or push bars 31,
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four bars are shown in the illustrated machine, whlch bars
successively push the completed tier from the powered roller
conveyor 29 onto a fixed transfer plate 32 (see Fig. 9)
having a continuous smooth upper surface. A push bar 31 con-
5 tinues to move the tier across the transfer plate 32 in thecontinued straight path of movement of the cartons. As
the cartons move off they are placed on a movable stripping
plate 33 having a continuous smooth upper surface which
plate 33 moves at a linear rate slightly exceeding the rate
10 of the push bar to receive a completed tier and place the
completed tier in the upper part of a stacking chamber
generally designated 35~
If a pallet 36 in the stacking chamber 35 is -
loaded, having received its top tier, the elevator 37 support- -~ ~
15 ing the pallet 36 will be lowered in the stacking chamber to -
a discharge position in the bottom of the stacking chamber. ~'
The pallet will be lowered onto a discharge conveyor 40 con-
sisting of support rollers along the sides and a central drive
chain to frictionally drive the pallet off the elevator.
2Q The elevator 37 is shaped to fit around the rollers and drive
chain to thus set the pallet onto the discharge conveyor section
within the ætacking chamber. The pallet will then be moved
by the discharge conveyor 40 out of the stacking chamber 35.
At this time it will be necessary to move an empty pallet 41
25 into the top of the stacking chamber as the stripping plate
33 moves a new tier into position over the stacking chamber.
As seen in Fig~ 10, guide means are provided for lifting an
empty pallet 41 of a pallet inserting conveyor 42. The
guide means comprise parallel axially and transversely aligned
3Q rails 43 mounted to swing to and out of the path of the pallet
to be engaged by a depending rib 44 on the stripping plate
; 33. The rib 44 will engage one edge of the pallet 41 sup-
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ported on the rails 43 and slide the pallet along the guide
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rails into a position above the stacking chamber 35.
This is most clearly shown in Fig. 10 and as the stripping
plate 33 moves from beneath the transfer plate 32 toward
the stacking chamber the cartons are placed thereon under
5 the pushing force of a bar 31. The stripping plate 33 is `
thus moving the empty pallet along the guide means and the
cartons into the stacking chamber. As the stripping plate
returns to its position under the transfer plate 32 the
cartons are stripped from the plate and drop onto the ~-
empty pallet 41 supported now on the rails 43 as shown in
Figures 6, 7 and 11. When stripping plate 33 is returned
under the fixed transfer plate 32, the guide means 94, 95
pivot about a fixed axis 107, 111 to lower the pallet 41 and
the first tier of cartons. The stripping plate 33 then ,
15 moves outward toward the stacking chamber to receive the ,
second tier as it is forced off the transfer plate 32.
The stripping plate is then pulled from under the second ,
tier as shown in Fig. 11. At this time the loaded pallet
36 has moved from the stacking chamber 35 under the transfer
20 force of the discharge conveyor 40. The elevator 37 is `~
rapidly raised to a position to support the new pallet 41
which is now loaded with two tiers of cartons. When the ~ -
elevator 37 is raised to the position to support the
second tier of cartons the stripping plate is returned to
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25 receive the third tier and the guide means supporting the
pallet 41 are lowered to a position out of the way of the
elevator 37 and of the conveyors. This is illustrated in
Fig. 12. The conYeyor 42 for inserting an empty pallet is
positioned between the guide rails and when the guide means
30 are lowered an additional pallet 51 may be moved into a posi- ~
tion on the canveyor 42 beneath the stripping plate. It is ~ `
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retained on the conveyor 42 which is at a level to permit the
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free reciprocatory movement of the stripping plate 33 and the
depending rib 44 as it moves back and forth to load the
pallet 41 in the stacking chamber without interference.
After the pallet is completely filled with cartons it will
be lowered onto the discharge conveyor 40 and the next pallet
51 will be moved with the next tier of cartons over the
stacking chamber 35 and be supported on the guide means.
The guide means for the empty pallets will be described in
greater detail hereinafter.
Turning now to a more detailed description of ;,
the machine it will be seen in Fig. 2 that the secondary
rotators 21 and 22 are supported above the roller conveyor
in the tier-forming section by a pair of frames 60 which are
- pivotally mounted to a bridge 61 which extends across the bed
, 15 of the machine and the two separating roller conveyors 28
and across the paths of the cartons., The frames 6Q position
a pair of rotatable star wheels 62 and 63 respectively in the '
path-of the cartons such that the cartons will move against
the then positioned transversely extending arm of the star -'
wheel. Motors 64 in the form of cylinders and reciprocating
pistons are pivotally connected between the bridge 61 and the
frames 60 to independently raise and lower the frames 60 and
with them, the star wheel 62 and 63, These motors 64 permit
the arms of the rotators to be rapidly raised a height suf-
, 25 ficfent to avoid contact with the cartons, Earlier known
machines utilizing vertically movable rotators for tier ,
forming have moved about a pivot axis positioned parallel ~ -
to the direction of movement of the cartons. This movement
requires movement of the rotator about an arc such that the
3a rotator has to be raised a significant amount before the
entire catch arm is raised above the path of the cartons.
In the present embodiment, when any of the arm is out of the
path the entire arm is clear. -,
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Separate motors 65 are positioned one on each of
the frames 60 to rotate the star wheels as desired. These
motors 65 will rotate the star wheels 90 upon actuation.
The rotators 21 and 22 are independently operated and they
5 may rotate oneor two cartons as the cartons move through --
the tier-forming station to produce the pattern desired for
each tier. In most instances to form a seven-carton tier
the rotators are operated independently and after a row of four
cartons is formed one rotator will rotate a pair of cartons
10 and the other will rotate one~ Then they reverse to form the
first row of a succeeding tier~ They may then raise to allow
cartons to pass without rotation to form the four carton rows
etc. The desired patterns for the tiers are formed with - ~ -
successive patterns differing such that the cartons will be --
15 stacked like bricks in a stable stack on the pallet.
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The squeeze conveyors 24 and 25 are positioned '-~
downstream from the secondary rotators 21 and 22 to gather
the cartons and place them in side-to-side or end-to-end
contact as determined by the pattern being formed.
Figs~4 and 5 illustrate the tier transfer and
stacking section of the machine. After the tier has passed
the final stop 26, the tier moves between the endless chains
30 to the edge of the stationary transfer plate 32 which -
transfers the tier to the stripping plate. The tiers are under - ~-
25 the control of the drive chains 30 and flight bars 31 after they ~
are formed. The chains 30 are driven from a set of sprockets 70 : ;
on a shaft 71. The shaft 71 is driven from a motor 73. The ;
motor 73 drives the chains simultaneously, intermittently -~
through predetermined cycles such that a bar 31 is positioned
30 and held at the downstream side of the lower idler sprocket -
74 of each chain for a time to allow the stripper plate 33
to return from the position over the stacking chamber 35 to
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its position beneath the transfer plate 32 with a bar 31 posi-
tioned to stop the return of the cartons. The chains 30 are
then driven again when a tier is formed at the stop 26 to
move a tier off the plate 32 and another tier onto plate 32
5 and allow the new tier to move between the chains 30. The
chains 30 follow a generally rectangular path around the
drive sprockets and then around four sets of idler sprockets
77, 78, 79 and 74.
The flight bar 31 to the rear of a tier positoned
on the plate 32 will serve as a stop for the tier moved past
the final stop 26 and along the rollers of the conveyor 29
toward the stationary plate 32. Positioned above the station-
ary plate 32 are guides 75 which aid in closing the cartons
to maintain a tier formed of closely positioned cartons on the
15 stationarY plate.
The stripping plate 33 is reciprocated by means
of a chain drive. A motor 8Q drives a drive chain 81 to
drive a pair of sprockets 82 on a shaft 83 around which
sprockets 82 are chains 85. The chains 85 are secured to
the stripping plate 33~ Each transverse edge of the stripping
; plate is supported by guide members 87 which guide the
stripper plate during its reciprocation from beneath the
transfer plate 32 to its position over the stacking chamber
35. The motor 80 and chains 85 drive the stripper plate in
25 a reciprocating pattern between its positions and so drives the
; stripper plate that its linear movement toward the position
oyer the stacking chamber is faster than the movement of the
.
chain driven bars 31 when it is being loaded. The movement
in the load position is slightly in advance of the drive of
3 the flight bars 31 such that the plate is moved from beneath
the transfer plate 32 a slight amount before the cartons
are placed thereon and the slight spacing of the cartons
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is corrected when the cartons are stopped by a bumper 86
placed in the path of the cartons and above the path of the
stripper plate 33 in the stacking chamber 35.
As the pallet within the stacking chamber is
5 filled and is moved to its lower position as explained here-
inabove, the nextcycle of the stacking sequence requires that ~
an empty pallet be moved into the stacking chamber. This is : -
accomplished by moving a pallet from beneath the stationary -
plate 32 to a position in the top of the stacking chamber. ~
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10 The pallet is placed beneath the plate 32 by the chain conveyor '~
42 which is operated during a stacking cycle. On transversely
spaced opposite sides of the bed for the machine are supported
guide means which will guide the pallet along a path from '
beneath the transfer plate 32 to a position in the uppermost
15 area of the stacking chamber. This guide means comprises
transversely and axially aligned rails 43 which may be swung
from a position out of the path of the pallets to a position
where they will lift the pallet from the conveyor 42 into a ;- -
position to have the pallet engaged by the depending rib 44 on
2Q the stripping plate 33. An electric eye is positioned at a
leyel an inch or so below the bottom of the stripping plate 33 :: ~
to stop the vertical movement of the guide means. The guide ~ -
rails 43 as shown most clearly in Figs. 4, 6, and 7 comprise `
bars or tubes which are circular in cross section and which ;- -
are formed at their ends with a tapered section such that the
pallet is moved easily along a straight path from one rail
to the next and will be guided onto that next rail along this
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tapered leading edge. The rails 43 comprise transversely 'i
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spaced symmetrical first supporting rails 89 positioned be~
30 tween the flights of the chain conveyor 42 and above each
support rail 89 is a guide rail 90. An additional pair of sup~
; port rails 91 are positioned between the downstram chain of ~`
the conveyor 42 and the stacking area 35~ A pair of trans- ;
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versely spaced symmetrical support rails 94 and guide rails
95 are positioned centrally within the stacking area. A pair
of stub support rails 96 and guide rails 97 are positioned
at the downstream side of the stacking chamber 35. As noted
in Figs. 6 and 7, the support rails 89 are fixed to the end
of L-shaped arms 101 which are pivoted about an axis 102 in
spaced brackets or ears 103. The guide rails 90 are supported
; at the end of T-shaped members 104 which have their opposite
ends connected to a pivot axis 105 on an arm 106, which arm
106 is pivoted at an axis 107 to a support 108. The base of
the T-shaped member 104 is connected by a pivot 109 to the
arm 101. The pivot axis 102 is provided by a pair of shafts
111 which extend one along each opposite side of the bed of
the machine. The shafts 111 are secured to the centers of
rotatable wheels or drums 112 which are driven from chains
113 which in turn are driven from the output sprockets 114
of a pair of synchronized reducers 115. The reducers 115
are driven by a suitable motor such that they can drive the
drums 112 to raise the guide rails 43 to lift the pallet off
of the conveyor 42. After the pallet is in position as deter-
mined by an electric eye sensor in the path of the pallet
the stripped plate 33 moves the pallet along the rails to its
position in the stacking chamber. The pallet as it is moved
into the stacking chamber by the stripping plate 33 is stopped
by a bumper 117 supported by a pair of extendable air cylinders
118. The air cylinders position the pallet relative to the
- cartons which are positioned by the bumper 86. This posi-
tioning of the pallet as it is moved out is necessary since
most pallet loads overhang the edges of the pallets slightly.
3 Then the cartons are stripped onto the pallet and the reducers
115 rotate the two shafts 111 to lower the pallet from the
position shown in Fig. 6 to the position shoun in Fig. 7. As
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it is moved to the position shown in Fig. 7 the pallet may
be lowered onto the elevator frame 37 whlch has returned or,
if the discharge conveyor is a little slower the pallet
may be lowered by the rails 94 within the stacking chamber
5 35 sufficiently to place a second tier of cartons upon
the pallet. The pallet is supported on the support rails
94 of the guide rail means 43 and is positioned transversely
within the stacking chamber 35 by the guide rails 95. When
the pallet and the first tier is lowered to the position
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shown in Fig~ 7, the support rails are moved toward the
outer edges of the pallet as the arms 101 swing downward
in an arc to lower the pallet~ The support rails 94 can ~ -
then be readily withdrawn from under the pallet placing
the same on the elevator 37 when it is returned to its
15 position in the top of the stacking chamber 35~ The guide
rails 43 will remain in a suspended position as the stacking
of the pallet is continued and the elevator 37 progressively
lowers the pallet sequentially by the height of a tier until
- such time as it is fully loaded and moves the pallet into -
contact with the discharge conveyor 40. The guide members will
~ then be moved back to a position as shown in Fig. 6 to re- --
; ceive a pallet and raise it to a position to be engaged by
the rib 44 of the stripper plate 33 and the cycle is repeated. ~ -
At this time the pallet has moved the stack low enough such
that there is no interference with the movement of the
support rails 94 into the top of the stacking chamber.
The operation of the stacking portion of the machine
and the sequencing of the various movements of the elements
is illustrated in Fig. 13. As will be noted on the graph,
30 the movement of the elevator follows the return of the
stripping plate 33 beneath the transfer plate 32 and this
requires approximately a half second of time. The stripper ,'
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104~5~i3
plate 33 will then move forward to position a tier over the
stack in one second. This movement is at a rate of approx-
imately 61 meters (200 ft.) per minute. The plate is again
retracted under the transfer plate 32 at the same rate. Thus,
the time ~or placing a tier on the stack requires approx-
imately 2-1/2 seconds. These three steps o~ operation are
repeated ~or each tier which may range from seven through
twelve tiers, depending on the height of the stack desired.
After the last tier is formed the elevator 37 is lowered in-
to the discharge conveyor 40 and the pallet is placed on thedischarge conveyor in a lapse time of one second and another
interval of one second is allowed then to raise the guide
rails 43 into position to accept the new pallet~ The pallet
is moved forward with a tier of cartons in the next second
of lapsed time and the plate is returned in another second.
Thus three seconds of time were allowed to load the empty
pallet into the stacking chamber and to place the first tier
on the pallet. The guide rails 43 are then lowered to lower
the first tier which requires a one-half second time interval
and the second tier is moved out and placed thereon in the
lapsed time of two seconds. During the interval of time that
the empty pallet and the first tier of cartons are moved in-
to the stacking chamber it will be noted that the elevator
may have returned or will begin to raise from its bottom
position in the stacking chamber up to a position to receive
the pallet. Itis thus in position to support the pallet
on its two transversely spaced bars and on its two longi-
tudinally positioned bars ~oined to the transverse bars. These
bars forming the elevator fit about the conveyor 40 in the
30 bottom of the stacking chamber.
The eleYator 37 is lowered to a position placing
the pallet on the discharge conveyor 40 after the elevator
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10415~;3
has been lowered stepwlse to interrupt the signal between
electric eyes positioned at the base of the stacking chamber.
The interruption of these electric eyes indicate to the
stepping mechanism of the machine that it will lower the
elevator and will also operate the guide means to lift the
empty pallet off of the elevator 42 and move it into the
top of the stacking chamber.
The timing and control for palletizing machines
are thus rather conventional electric eyes which indicate r`
10 whether a carton is in the proper position when it is de- ~ ~
sired that there be a carton in that position and to sense -
when a row of cartons has moved past a certain position
in the tier-forming area.
,
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- 17
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