U.S. patent number 3,768,382 [Application Number 05/112,558] was granted by the patent office on 1973-10-30 for stacker.
This patent grant is currently assigned to Zerand Corporation. Invention is credited to Norman C. Abler, Peter Zernov.
United States Patent |
3,768,382 |
Zernov , et al. |
October 30, 1973 |
STACKER
Abstract
An apparatus for automatically providing a gap or space in the
movement of one or more files of carton blanks conveyed in a
shingled relation on a delivery conveyor to an infeed conveyor or a
carton blank stacker or similar carton handling device, the
apparatus including a first member positioned in a transverse
relation to the direction of travel of the file of carton blanks to
engage the files and momentarily stop or hold the blanks while the
speed of the infeed conveyor is increased to provide a gap in the
file. The gap in the file of shingled carton blanks should be of
sufficient length to allow for removal of the carton blanks stacked
in the stacker. The first member can take the form of a clamp or
brake shoe, a catch plate, or a gripper wheel. Continuously driven
drive wheels can be provided to remove any loose, skewed or canted
blanks gripped between the first and second members and to feed the
carton blanks into the stacker.
Inventors: |
Zernov; Peter (Wauwatosa,
WI), Abler; Norman C. (Menomonee Falls, WI) |
Assignee: |
Zerand Corporation (New Berlin,
WI)
|
Family
ID: |
22344574 |
Appl.
No.: |
05/112,558 |
Filed: |
February 4, 1971 |
Current U.S.
Class: |
271/216;
271/69 |
Current CPC
Class: |
B65H
29/66 (20130101); B65H 33/12 (20130101); B65H
2701/176 (20130101) |
Current International
Class: |
B65H
33/00 (20060101); B65H 33/12 (20060101); B31b
001/98 (); B65h 029/68 (); B65h 033/06 () |
Field of
Search: |
;93/93DP
;271/63,68,75,76,49,50,77,78 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Simpson; Othell M.
Assistant Examiner: Desmond; E. F.
Claims
We claim:
1. A carton blank clamp apparatus for separating a file of carton
blanks being conveyed in a shingled relation on a conveyor to a
device downstream from the conveyor, said apparatus comprising,
a first member positioned above said blanks and in a transverse
relation to the direction of travel of said blanks, and
means for raising said carton blanks to a position in abutting
relation to said first member to clamp said carton blanks in a
hanging and feathered relation over the device and thereby stop the
motion of the carton blanks on the conveyor and allow the blanks on
the downstream side of the first member to fall freely onto the
device downstream from the conveyor.
2. The apparatus according to claim 1 wherein said raising means
comprises a second member positioned below said blanks in a
transverse relation thereto and being mounted for movement into
engagement with said first member.
3. The apparatus according to claim 2 including means for
maintaining said second member in a fixed relation with respect to
the conveyor.
4. The apparatus according to claim 1 including a resilient cushion
on said first member and an angle plate on said second member
positioned to engage said resilient cushion.
5. The apparatus according to claim 1 including means for
selectively setting the height of said first member with respect to
the conveyor.
6. The apparatus according to claim 1 including means for
supporting said first member for movement with said raising
means.
7. The apparatus according to claim 6 including means for biasing
said first member towards said raising means.
8. The apparatus according to claim 1 including means for pulling
loose or canted carton blanks clasped between said first member and
said raising means.
9. The apparatus according to claim 8 wherein said pulling means
comprises a drive wheel assembly supported at a distance from said
moving means equal to slightly less than the length of one of the
carton blanks.
10. The apparatus according to claim 9 including means for
adjusting the position of said drive wheel assembly with respect to
said raising means.
11. The combination of a carton blank stacker having an infeed
conveyor, a delivery conveyor for conveying carton blanks in a
shingled relation to said infeed conveyor, and an apparatus
positioned between said infeed conveyor and said delivery conveyor
for gripping carton blanks in the gap between the conveyors to
allow a stack of carton blanks to be removed from said stacker,
said apparatus comprising means for clamping the carton blanks at
the end of the delivery conveyor and elevating the clamped portions
of the blanks above said delivery conveyor whereby the clamped
carton blanks will hang in a feathered relation over the infeed
conveyor allowing the carton blanks downstream from said clamping
means to drop freely onto the infeed conveyor.
12. The combination according to claim 11 including means for
adjusting the height of said first member with respect to said
blanks.
13. The combination according to claim 11 wherein said clamping
means comprises a second cross member positioned in a transverse
relation below said blanks.
14. The combination according to claim 13 including means for
maintaining the second cross member in a predetermined relation to
the top of the delivery conveyor.
15. A carton blank clamp assembly for stopping the motion of a
number of carton blanks being conveyed in a shingled relation on a
conveyor to a carton blank stacker, said assembly comprising,
a first cross bar positioned above the blanks in a transverse
relation to the direction of motion of said blanks,
and means for moving said carton blanks into engagement with said
first cross bar to clamp the carton blanks in a hanging position at
the end of the conveyor whereby the carton blanks in the clamp
assembly are held in a feathered relation over the input end of the
stacker.
16. The clamp assembly according to claim 15 including means for
adjusting the height of said first cross bar relative to said
conveyor to accommodate the carton blanks which stack up behind the
clamp assembly when the clamp assembly is closed on the
conveyor.
17. The clamp assembly according to claim 15 including means for
maintaining the second cross bar in a predetermined relation to the
top of the conveyor.
18. The clamp assembly according to claim 15 including means for
allowing said first cross bar to move upwardly with said second
cross bar.
19. The clamp assembly according to claim 15 including means for
pulling carton blanks from said clamp assembly which are not
securely held by said clamp assembly.
20. A carton blank pulling device mounted on an infeed conveyor for
removing loose or skewed carton blanks clamped in a clamp assembly
located at the end of a delivery conveyor having a number of files
of carton blanks arranged in a shingled relation thereon, said
device comprising a drive wheel assembly corresponding to each of
said files of carton blanks, each of said assemblies including a
drive wheel for engaging any carton blanks extending outward from
the assembly a distance nominally equal to or less than the length
of a carton blank,
and means for driving said assembly at the same speed as the infeed
conveyor.
21. The carton blank pulling device according to claim 20 including
means for adjusting the distance of the drive wheel assembly from
the clamp assembly.
22. The combination according to claim 11 including means for
increasing the speed of the infeed conveyor.
23. The combination according to claim 11 including means for
positively moving carton blanks from the infeed conveyor to the
stacker.
24. The combination according to claim 23 wherein said moving means
includes a number of drive wheel assemblies mounted at the
discharge end of the infeed conveyor and positioned to ride on the
surface of said carton blanks.
25. In combination, a carton blank stacker having an infeed
conveyor,
a delivery conveyor for continuously conveying files of carton
blanks in a shingled relation to said infeed conveyor,
and means for holding said files at the end of said delivery
conveyor in a feathered relation over said infeed conveyor for a
sufficient duration to allow for the removal of the stacks of
carton blanks from said carton blank stacker before the next carton
blanks are conveyed to the stacker.
26. The combination according to claim 25 wherein said holding
means comprises a clamp assembly having a cross bar positioned
above said delivery conveyor and means for moving said blanks into
engagement with said cross bar to momentarily stop the motion of
the carton blanks on the end of the delivery conveyor.
27. The combination according to claim 25 including means for
operating said infeed conveyor at a greater speed than the delivery
conveyor.
28. The combination according to claim 11 including a machine
counter connected to actuate the clamping means.
29. Carton blank handling apparatus for separating a file of carton
blanks which are being conveyed along a path and in overlapping
shingled relationship to one another, said apparatus comprising,
means for shifting said file of shingled blanks vertically so as to
dispose a portion of said file of blanks in a hanging and feathered
relationship where the blanks in said portion hang and are
separated from one another at their rear ends in respect to the
direction of travel, and clamping means for causing said file of
carton blanks on the downstream side of said shifting means in
respect to the direction of travel along said path to be
momentarily retarded in their movement, and thereby cause said
hanging blanks to separate from said file.
30. The apparatus according to claim 29 including a delivery
conveyor and an infeed conveyor, said apparatus being located at
the end of said delivery conveyor whereby said clamped carton
blanks overhang said infeed conveyor.
Description
BACKGROUND OF THE INVENTION
Carton blank stackers of the type contemplated herein are
positioned at the end of a discharge conveyor of a carbon blank
cutting, scoring, and/or printing machine. The carton blanks are
usually conveyed from the machine in a shingled relation, and a
stacker is used to automatically stack the cartons for shipment.
Once the cutting, scoring and printing machine has been started, it
is run continuously and as a consequence the carton blanks are
conveyed continuously to the stacker. Separation of the file of
shingled carton blanks on the conveyor to allow for the removal of
a stack of carton blanks from the stacker has conventionally been
accomplished by means of a number of flat swords. The swords are
moved into the stack of carton blanks on the stacker to support the
incoming carton blanks and the stack of carton blanks below the
swords are lowered and removed from the stacker. These swords often
cause considerable damage to the carton blanks in the stack due to
the engagement of the swords with the cuts and/or openings in the
blanks. If there is printed matter on one surface of the blanks,
the swords tend to scratch or mar the printed surface of the
blanks. When blank thickness varies from one file to another, some
files will accumulate extra cartons in the stack portion that
remains above the swords, eventually choking the stacker.
Similarly, other files will become depleted of cartons above the
swords causing poor jogging action. This results in large counting
errors and an undesirable amount of operator attention to equalize
the stacking levels from file to file.
SUMMARY OF THE INVENTION
The apparatus of the present invention is used to momentarily stop
the movement of a section of a file of shingled carton blanks on a
conveyor to provide a gap therein of sufficient length to allow for
the removal of a stack of carton blanks from the stacker. This can
be achieved by using a brake bar, catch plate assembly or gripper
wheel assembly to engage the carton blanks on the delivery conveyor
while the blanks downstream are rapidly moved into the stacker. The
brake bar or clamp assembly can be moved into clamping engagement
with the shingled carton blanks to raise the clamped carton blanks
off of the conveyor to allow the carton blanks on the conveyor to
bunch up evenly behind the clamp assembly while the carton blanks
following the assembly are rapidly removed from the stacker.
The clamp assembly includes a first or upper cross member which is
biased downwardly toward the file of carton blanks on the conveyor.
A second or lower cross member is positioned below the file of
carton blanks on the conveyor and is hydraulically moved upward
toward the upper cross member to clamp the carton blanks
therebetween. The upper cross member is free to move upward with
the lower cross member to prevent the carton blanks on the conveyor
from moving over the top of the upper cross member.
The catch plate assembly includes an angularly disposed plate
supported on pivotally mounted arms above the conveyor. The arms
are rotated to move the catch plate to an angularly disposed
position with respect to the conveyor. The carton blanks on the
delivery conveyor will ride up on the catch plate while the blanks
downstream of the catch plate are moved rapidly into the
stacker.
The gripper wheel assemblies include one set of gripper wheels
located at the end of the delivery conveyor and a second set of
gripper wheels located at the beginning of the infeed conveyor.
Both sets of wheels are driven at the same speed as the
corresponding conveyor and are located to provide positive
separation of the carton blanks in each file when the infeed
conveyor is increased in speed.
A carton blank pulling device can be provided on the stacker to
prevent jamming or clogging of the stacker by a loose, canted or
skewed carton blank held by the clamp assembly. Since the spacing
between the carton blanks may be irregular, the clamp assembly may
grab only a portion of the last carton blank so that it is loose or
skewed in the clamp assembly. On release from the clamp assembly to
start a new stack, any skewed or canted carton blank will jam the
stacker. The carton blank pulling device provides for the positive
movement of the carton blanks when released from the clamp assembly
and thereby prevents jamming or clogging of the stacker.
THE DRAWINGS
FIG. 1 is a side view in elevation showing a portion of a discharge
conveyor and a stacker having an infeed conveyor spaced from the
discharge conveyor, the carton blank clamp assembly of the present
invention being shown positioned in the space between the two
conveyors;
FIG. 2 is an enlarged view of portions of the stacker and the clamp
assembly showing the clamp assembly in the open position in solid
lines and in the closed position in dotted lines, certain parts
being shown in section or broken away;
FIG. 3 is a front elevation view of the clamp assembly, certain
parts being shown in section or broken away;
FIG. 4 is a perspective view of a portion of the clamp assembly
shown closed and elevated with the carton blanks shown feathered on
the downstream side of the clamp assembly;
FIG. 5 is a front view of the carton pulling drive wheel assembly
showing one of the drive wheels, certain parts being shown in
section or broken away;
FIG. 6 is a side view in elevation of an alternate apparatus for
separating the carton blanks in a file of carton blanks;
FIG. 7 is a side view in elevation of another apparatus for
separating the carton blanks in a file of carton blanks.
DESCRIPTION OF THE INVENTION
The clamp assembly 10 of this invention as seen in FIGS. 1 and 2 is
used in combination with a carton blank delivery conveyor 12 and a
stacker 14 as a means for providing a gap or space in the file of
carton blanks by stopping the movement of a file of carton blanks
16 on the end of the delivery conveyor. This gap should be of
sufficient duration to allow for the removal of the stack of carton
blanks 16 from the stacker 14 before the blanks 16 held by the
clamp assembly 10 are released for movement onto the stacker 14.
The delivery conveyor 12 includes one or more belts 15 and is
commonly found at the discharge end of a cutting, scoring and/or
printing machine. The carton blanks 16 emerge from the machine and
are carried by the conveyor 12 in a shingled relation to the
stacker 14. One or more files of carton blanks 16 may be conveyed
on the delivery conveyor 12 at one time. Generally a counter is
provided on the machine to indicate the number of blanks 16 which
have been cut, scored, and/or printed and deposited on the conveyor
12.
THE STACKER
The carton blank stacker 14 shown in FIGS. 1 and 2 of the drawings
is also of a conventional type having an infeed single belt
conveyor 18, an elevator 20, a set of jogging or vibrating plates
22, a stack removing pusher plate assembly 24, and a stack height
control assembly 26. The infeed conveyor 18 is positioned at the
end of the delivery conveyor 12 in a spaced relation thereto to
transfer carton blanks 16 from the delivery conveyor 12 to the
elevator 20. The infeed conveyor 18 is driven at a normal speed by
means of a motor 19 and at high speed by means of a high speed
motor 21 provided on the frame of the stacker 14. Although two
motors are shown for driving the infeed conveyor, the infeed
conveyor can also be driven by means of a variable speed drive
motor. The jogging plates 22 vibrate the carton blanks 16 as they
drop onto the elevator 20 to form a vertical stack on the elevator
20.
The height of the elevator 20 is continuously changed as the level
of the stack increases so that the top of the stack is positioned
just below the delivery conveyor 12. This is accomplished by means
of the stack height control assembly 26 which is connected to
control a number of hydraulic piston and cylinder assemblies 28
which are used to support the elevator 20, as is well known in the
art. When the stack of carton blanks 16 on the elevator 20 reaches
the desired height, the stacker 14 is run through an unloading
cycle to remove the stack from the elevator 20. Briefly, this
involves the actuation of a limit switch to operate the down
solenoid valve for the hydraulic assemblies 28 to drop the elevator
20 to the bottom of the stacker 14. The elevator closes a limit
switch to actuate the pusher plate assembly 24 to push the stack of
carton blanks 16 off the elevator 20 onto a table or conveyor 23.
The return motion of the pusher plate assembly 24 is used to close
the limit switch for the elevator up solenoid valve to move the
elevator back to a position adjacent the infeed conveyor 18.
Although a jogging type stacker is shown in the drawings, it should
be apparent that other types of stackers can be used with the clamp
assembly of this invention.
CARTON BRAKE BAR OR CLAMP ASSEMBLY
In accordance with one aspect of the invention, the brake bar or
clamp assembly 10 is positioned at the end of the delivery conveyor
12 to momentarily grip or clamp the carton blanks 16 when a stack
of carton blanks is to be removed from the stacker 14. The clamp
assembly 10 stops the movement of the carton blanks 16 at the end
of the delivery conveyor 12 by displacing the carton blanks from
the file for a period of time sufficient to allow for the removal
of the stack of carton blanks from the elevator 20. Normally, this
would be for a period of approximately 3 to 5 seconds. The carton
blanks 16 are held as seen in FIG. 4 in a separated or feathered
position to allow the carton blanks on the downstream side of the
clamp assembly to move freely from the clamp assembly.
The clamp assembly 10 as seen in FIGS. 2 and 3 generally includes a
first or an upper cross member or bar 30 positioned transversely
above the carton blanks 16 on the delivery conveyor 12 and a second
or lower cross member or bar 32 positioned below the carton blanks
on the delivery conveyor 12. The upper cross member 30 is supported
by means of a pair of legs or rods 36 positioned in hollow square
posts 34 secured to each side of the frame of the stacker 14. The
cross member 30 is connected to the legs or rods 36 which are
positioned within the posts 34 for vertical movement with respect
to the conveyor 12. The cross member 32 is connected to bars 60
which are positioned for vertical movement in hollow square posts
68.
Means are provided for selectively adjusting the height of the
cross bar 30 to accommodate the carton blanks 16 which stack up on
the delivery conveyor 12 when the clamp assembly 10 is closed. Such
means is in the form of a number of pins 38 which are adapted to be
inserted into holes 40 provided in the posts 34. The rods 36 are
biased downward against the pins 38 by means of springs 42.
Means are provided for moving the lower cross member 32 into
abutting relation to the upper cross member 30 to grip or clamp the
carton blanks 16 at the end of the delivery conveyor 12. Such means
is in the form of a hydraulic piston and cylinder assembly 44 which
includes a cylinder 46 connected to the frame of the stacker 14 and
a piston rod 48 connected to the cross member 32. The piston and
cylinder assembly 44 is controlled by a solenoid actuated control
valve as is generally understood in the art. The cycle of operation
of the clamp assembly 10 can be initiated by an electric signal
provided by the counter on the cutting, scoring and/or printing
machine, a selectively positionable stack height limit switch
positioned to be engaged by the elevator 20, or a manual unload
switch, as described hereinafter. The upward movement of the cross
member 32 is used to actuate a limit switch assembly which is
connected to control the solenoid valve for assembly 44 and to
actuate a time delay relay for the high speed conveyor motor
21.
Means are provided for supporting said first cross bar 30 for
movement with said second bar 32 to prevent the carton blanks 16
from bunching up behind the clamp assembly to a height where they
pass over the top of the cross member 30 while the clamp assembly
10 is closed. It should be noted that stopping the movement of the
carton blanks 16 at the end of the delivery conveyor 12 will cause
the carton blanks 16 on the conveyor belts 15 to stack up behind
the clamp assembly 10. If the carton blanks stack up to a height
higher than the cross member 30, the carton blanks will spill over
the top of the cross bar. This is prevented by means of the
movement of the upper cross member 30 which moves upward with the
lower cross member 32 to a height where the carton blanks 16 bunch
up on the delivery conveyor 12. As seen in FIG. 3, the legs 36 are
connected to each end of the cross member 30, and are free to move
upward within the square posts 34 against the bias of springs 42.
When the clamp assembly 10 is opened, the upper cross member 30
will follow the motion of the lower cross member 32 until the bars
36 engage the pins 38.
The distance between the upper cross member 30 and the top of the
conveyor belts 15 can be varied to accommodate the contemplated
height of the carton blanks 16 which bunch up on the delivery
conveyor 12. This is accomplished by means of the pins 38 and holes
40 provided on each of the tubular support posts 34. In this
regard, the pins 38 can be positioned in any one of the row of
holes 40 which are spaced at one-half inch intervals.
Means are provided for maintaining the lower cross member 32 in a
fixed or constant relation with the conveyor 12 to assure an even
amount of pressure across each file of carton blanks 16 across the
conveyor 12. Such means is in the form of the pair of bars 60 each
having a row of ratchet teeth 62 on one side and a pair of gears 64
secured to each end of a rod 66. The bars 60 are connected to each
end of the lower cross member 32 by screws 65 and are positioned
for vertical movement in the hollow square guide posts 68 mounted
on the frame of the stacker 14. The rod 66 is journalled for
rotation in brackets 70 provided on the guide posts 68 so that the
motion of one of the gears 64 will produce an equal motion in the
other of the gears 64. Whenever one of the bars 60 moves, the
motion of the bar 60 is transferred to the other bar 60 through the
gears 64 and rod 66.
Positive gripping or clamping of the carton blanks 16 between the
cross members 30 and 32 is provided by means of an angle plate 50
provided on the top of the cross member 32 and a pad 51 provided on
cross bar 30. The angle of the pinch of the plate 50 is designed to
raise the loose ends of the carton blanks 16 which are squeezed
between the upper and lower cross members 30 and 32. In this
regard, as the lower cross member plate 50 is pushed into the
cushion 51 there is a tendency for the carton blanks to tilt to the
angle of plate 50 thus raising the outer or loose end of the carton
blanks off of the conveyor 18. The forward edge 49 of the plate 50
is rounded to cause the blank to warp because of the nip between
the plate 50 and the pad 51. The pressure or nip must be maintained
along the length of the carton blank in order to prevent the carton
blank from coming loose in the clamp assembly after the clamp
assembly 10 has been raised above the conveyor 12.
CARTON BLANK PULLING DEVICE
In the event that a carton blank 16 on the downstream side of the
clamp assembly 10 is not grasped tightly by the cross bars 30 and
32, the blank 16 may become canted or skewed slightly with respect
to the other carton blanks in the clamp assembly. On release of a
canted blank 16, the blank 16 will jam the stacker 14 if turned at
an angle which is too great to be handled by the vibrating or
jogging plates 22. This is prevented by providing means for drawing
or pulling the loose or canted carton blank 16 from the clamp
assembly. Such means comprises a number of rubber wheel drive
assemblies 71 as seen in FIGS. 2, 4, and 5 provided on the conveyor
18 for the stacker 14.
In this regard, and referring to FIG. 4, it should be noted that
the outer ends of the carton blanks 16 when clamped in the clamp
assembly 10 hang loosely in a separated or featured relation on the
downstream side of the clamp assembly. The drive assemblies 71 are
located at a distance from the clamp assembly 10 slightly less than
the length of the carton blank 16. If a blank is loose or skewed,
it will then be engaged by the drive wheel assembly and pulled
therefrom.
Each of the assemblies 71 is mounted on a common drive shaft 72
which is journalled for rotation in bearings 74 provided in support
plate arms 76. The support arms 76 are secured to a support shaft
75 pivotally mounted on the frame of the stacker 14. Each of the
assemblies 71 includes a link 78 pivotally mounted on a pulley 80
secured to the drive shaft 72 by a screw 82. A second pulley 84 is
mounted for rotation on a pivot pin 86 located at the other end of
the link 78 and is connected to the first pulley by a belt 88. A
drive wheel 90 having a rubber friction belt 91 on its outer
surface is secured to the second pulley 84 in a position to ride on
the conveyor 18. Means are provided for driving the drive shaft 72
in the form of a V-belt 92 mounted on a pulley 94 provided on shaft
72 and a pulley 96 journalled on the end of support shaft 75. The
pulley 96 is connected to a sprocket 97 which is driven
continuously by means of the drive chain 98 for the infeed conveyor
18 as described below.
The distance of the drive roller 90 from the end of the clamp
assembly 10 is adjusted by means of a screw 100 and gear 102
provided on the end of shaft 75. In this regard, the gear 102 is
secured to the end of the shaft 75. The screw 100 is journalled for
rotation in bearing blocks 104 and 106 provided on the stacker
conveyor 18. A hand crank 108 is secured to the end of the screw
100. It should be noted that the distance a from the periphery of
the drive wheel 90 to the axis of shaft 72 is greater than the
distance from the axis of shaft 72 to the surface of the conveyor
18 when the support arms 76 are perpendicular to the conveyor 18.
With this arrangement, the drive wheel 90 will always be located on
the downstream side of the arms 76 as the support arms are pivoted
about shaft 75. The belt 88 also provides a means for directing the
blanks 16 downwardly toward the drive wheel 90. As seen in FIG. 2,
the loose ends of any carton blank that happens to extend outward
from the clamp assembly 10 will engage the belt 88. Since the belt
88 is moving downward, it will direct the end of the carton blank
toward the drive wheel 90.
The drive wheel 90 is positioned to ride on conveyor 18 in the line
of travel of one of the files of carton blanks 16 and at a distance
from the clamp assembly 10 substantially equal to the length of a
carton blank 16. If a carton blank 16 is skewed or canted it will
extend outward from the clamp assembly a distance greater than the
length of a carton blank 16 and will be engaged by the wheel 90.
Since the wheel 90 is driven continuously, it will pull any loose
or canted blank 16 out of the clamp assembly 10. Any securely held
carton blank will be pulled backward from under the wheel by the
clamp as it raises.
FEED OR DRIVE WHEEL ASSEMBLY
The carton blanks 16 are fed directly into the jogging plates 22 by
means of a number of positively driven drive wheel assemblies 110
provided on the end of the infeed conveyor 18. Each of the drive
wheel assemblies 110 is pivotally supported on a drive shaft 112
journalled for rotation in support plates 114 which are secured to
each side of the stacker 14. Each assembly includes a link 116
pivotally mounted on a pulley similar to pulley 80 which is secured
to the shaft 112. A second pulley 120 is supported on a pin 122
secured to the other end of link 116 and a drive wheel 124 similar
to wheel 90 is secured to the pulley 120. The second pulley 120 is
connected to the pulley 118 by a belt 126.
The drive shaft 72 for the drive wheel assemblies 71 and the drive
shaft 112 for the drive wheel assemblies 110 are both driven by
means of the infeed conveyor drive chain 98. In this regard, the
drive sprocket 97 is secured to pulley 96 on shaft 75 and a drive
sprocket 130 is secured to the drive shaft 112. Idler sprockets
132, 134, 136, and 138 are provided on support plate 114 to guide
the chain 98 around drive gear 130. Idler sprockets 140 and 142 are
provided on each side of sprocket 97 to guide the chain 98 around
sprocket 97. The drive chain 98 is trained around a drive sprocket
144 driven by means of motors 19 and 21, an idler sprocket 146, the
idler sprockets 132 and 134, drive sprocket 130, idler sprockets
136 and 138, conveyor drive sprocket 148, idler sprocket 140, drive
sprocket 97, idler sprocket 142 and back to drive sprocket 144. It
should be noted that the direction of peripheral motion of the
conveyor 18 and the drive wheels 90 and 124 is always in the same
direction.
The speed of the infeed conveyor 18 is increased to rapidly clear
the carton blanks 16 from the stacker by means of high speed motor
21. In this regard, the high speed motor 21 is connected to the
drive gear 144 by a conventional overrunning clutch assembly 146.
As soon as the clamp assembly 10 reaches the upper position with
the carton blanks 16 gripped tightly therein, the infeed conveyor
18 as well as the drive wheel assemblies 71 and 110 are speeded up
to clear the infeed conveyor rapidly.
CATCH PLATE ASSEMBLY
Referring to FIG. 6, an alternate means is shown for providing a
gap in the files of carton blanks 16 being conveyed on a delivery
conveyor 12 to an infeed conveyor 18. Such means is in the form of
a catch plate assembly 150 mounted above the conveyor 12 for
movement into engagement with the files of carton blanks 16. In
this regard, the catch plate assembly 150 includes a plate 152
supported by lever arms 154 for pivotal movement about pivot shaft
156. The pivot shaft 156 can be rotated by a hydraulic cylinder
assembly 44 as described above. The piston 48 being connected to a
lever arm 160 connected to the shaft 156 as is generally
understood. The hydraulic cylinder assembly 44 can be actuated by
any known counter system to move the plate 152 into engagement with
the carton blanks on the file.
Separation of the carton blanks 16 in the file to produce a gap of
sufficient duration to clear the stacker magazine 162 is aided by
increasing the speed of the infeed conveyor 18. This is
accomplished by means of a variable speed motor 164 connected to
drive the conveyor 18. The variable speed motor 164 normally
operates at the same low speed as the drive motor 166 for the
delivery conveyor 12. The variable speed motor 164 is switched to
high speed operation at about the same time as the plate 152
engages the carton blanks 16. The infeed conveyor 18 is driven at
an accelerated speed for a short period of time to move the carton
blanks 16 on the conveyor 18 rapidly into the stacker magazine
162.
GRIPPER WHEEL ASSEMBLY
In FIG. 7, another means is shown for providing a gap in the files
of carton blanks 16. Such means is in the form of a pair of gripper
wheel drive assemblies 170, 172 which are operatively connected to
be driven at the same speed as the corresponding conveyors 12 and
18. In this regard, the drive wheel assembly 170 includes a number
of resilient friction wheels 174 which can be similar to the wheel
assemblies 71 described above. Wheels 174 are mounted on the ends
of arms 176 which are connected to a shaft 178 supported by arms
180. The wheels 174 are driven in the same direction as the
conveyor 12 and at the same speed off of the drive motor 166. The
drive wheel assembly 172 includes a number of resilient wheels 182
mounted on arms 184 which are secured to a shaft 186 secured to
support arms 188. The wheels 182 are driven in the same direction
and at the same speed as conveyor 18 by a variable speed motor
164.
The carton blanks 16 on the conveyor 18 are separated from the
carton blanks on the conveyor 12 by means of the motor 164 which is
operated at high speed to increase the speed of the conveyor 18.
The carton blanks on conveyor 18 will be moved at a high speed into
the stacker thus creating a gap between the last blank on the
conveyor 18 and the next blank on delivery conveyor 12. The gripper
wheel assembly 170 will continue to operate at the same speed as
conveyor 12 and the gripper wheel assembly 172 will operate at the
same speed as the conveyor 18. The gripper wheels 174 will prevent
or positively hold the carton blanks 16 on the conveyor 12 in the
file until the blanks 16 clear the wheel 174. The gripper wheels
182 will increase in speed with conveyor 18 assuring that the
blanks do not slip on the conveyor 18 as the speed of conveyor 18
increases.
THE OPERATION (FIGS. 1 AND 2)
Unloading of a stack of carton blanks from the elevator 20 of the
stacker 14 follows a conventional cycle of operation. The down
solenoid valve for the elevator 20 is actuated by an electric
signal to move the elevator to a down position. A normally open
limit switch for the pusher plate assembly 24 is closed by the
final downward motion of the elevator 20 to actuate a pusher plate
extension solenoid valve to push the stack off of the elevator 20
onto the table or conveyor 23. When the pusher plate reaches the
end of its stroke, a limit switch is closed to actuate the pusher
plate return solenoid to retract the pusher plate. The final
movement of the return motion of tthe pusher plate is used to close
a limit switch to actuate the up solenoid for the elevator 20. The
final motion of the elevator 20 is used to re-actuate the height
control assembly 26. The cycle of operation of the stacker 14 can
vary depending on the type of stacker being used, however,
regardless of the type of stacker used, a control signal must be
provided in order to initiate an unloading cycle.
Prior to initiating the unloading cycle for the stacker 14, the
carton blanks 16 on the conveyors are stopped to allow time to
unload the stack of carton blanks. This is accomplished by the
clamp assembly 10. The cycle of operation for the clamp assembly 10
can be initiated by means of a signal provided by the machine
counter, a stack height limit switch on the elevator 20 or by a
manual switch. The signal from any one of these sources is used to
actuate the up solenoid valve for the hydraulic assembly 44 and to
close a relay for a holding circuit for the unloading cycle for the
stacker 14. The lower cross member 32 is moved upward by the
hydraulic assembly 44 pushing the carton blanks 16 against the
upper cross member 30. Both members 30 and 32 continue to move
upward until they reach their upper position, as described above.
The final motion of the cross member 32 is used to actuate the
limit switch assembly which has a first switch to actuate a time
delay relay, a second switch to open the circuit to the up solenoid
valve for assembly 44, and a third switch to start the high speed
conveyor motor 21. The high speed motor 21 drives the conveyor 18
at high speed to move the carton blanks 16 which are still on the
infeed conveyor 18 rapidly into the stacker 14.
The time delay relay, at the end of the preset time period,
performs four functions: a) opens a limit switch for the high speed
motor 21 stopping high speed operation; b) opens a limit switch for
the height control assembly 26; c) closes the limit switch for the
down solenoid valve for the hydraulic assembly 44; and d) provides
the signal to start the unloading cycle for the stacker 14. The
conveyor 18 should be clear at the end of the preset time
period.
The final return motion of the elevator 20 is used to actuate a
limit switch assembly that includes limit switches for: a) opening
the holding circuit for the unloading cycle; b) opening the circuit
for the time delay relay; and c) closing a circuit for the height
control assembly.
At approximately the same time that the elevator 20 reaches its
upper position, the carton blanks which were released from the
clamp assembly 10 will start to drop onto the elevator 20. If an
infeed conveyor for the stacker is not used, the clamp assembly 10
should be left in the upper position at least until the elevator up
solenoid is actuated on the return movement of the elevator 20. The
clamp assembly 10 will then open and release the carton blanks
directly onto the elevator 20.
RESUME
The clamp assembly 10 described herein provides a simple but
effective means for delaying the movement of a file of carton
blanks while a stack of the carton blanks is being removed from the
stacker. Elevating of the carton blanks during the delay period
prevents the bunched up carton blanks from moving over the top of
the clamp assembly and at the same time maintaining the carton
blanks in an orderly arrangement behind the clamp assembly.
The carton blank pulling device reduces the possibility of jamming
of the stacker. This is achieved by removing any loose or canted
carton blanks from the clamp assembly. The carton blank pulling
device is provided with a positive drive so that it operates at the
same speed as the infeed conveyor to the stacker.
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