Note: Descriptions are shown in the official language in which they were submitted.
6~g~ `
The presen-t invention relates to a method of, and apparatus for,
feeding corrugated blanks from a stack in which the lowermost
blank is advanced to processing machinery on a feed bed which ~,
comprises rollers mounted above a vacuum source in such manner
as to enable the advancing blank to be held flat while mi~imizing
Wh; ~
friction between the advancing blank and the feed bed~h~e the
subject invention has utility in any sheet feeding system, it ~'
.,relates primarily to corrugated blank feeding equipment utilized ~ ,'
in the corrugated paper industry wherein blanks are stacked and
must subsequently be fed to processing equipment such as folding, ,~
cutting, creasing, and coating machines.
More particularly, the subject invention relates to
feeding equipment wherein the lowermost blank is advanced from
beneath the stack as contrasted to top sheet feeding .
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1~699~8
which ls utilized in some systems.
The pri,or art discloses many systems for feeding
blanks which have featured various ways to apply suction to ~,
prevent the warped edges of advancing blanks from causing jam-
ups which result in machine down time. Standard feed beds of
the type disclosed in U. S. Patent 3,754,752, issued August 28,
1973, to William S. Thayer, have utilized a perforated base
plate to enable the suction to be applied to the lowermost
blank to flatten warped or curled blanks during advancement.
In addition to the perforated plate type of structure,
elongated rib-like vacuum chambers have also been used for the
purposes of "flattening" or holding down warped blanks. Of
detrimental consequence in both of these systems is the creation
of friction between the blank and the table surface which must
be overcome by the kicker device or other means used to
advance the boards to the processing machinery. If the vacuum
is too strong, inordinate friction is created between the
advancing blank and the feed table surface requiring extreme ~;
force from the kicker device to push the sheets into the ~ ,~
processing machinery where they are normally received by feed
rolls. If the vacuum is relieved, then the front edge of the
advancing blank may lift off the table causing jam ups, par- ~,
ticularly if the blank is warped somewhat. In most standard
processing ,
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~a369~
machinery in the corrugated box industry, gates are positioned
adjacent the feed rolls to prevent more than one blank from
being fed to the processing machine simultaneously. It is
against these gates that jam ups will occur when the vacuum
is not sufficient to prevent the curling up of edges of warped
board.
Additional types of suction assist devices have been
utilized such as disclosed in U. 5. Patent 3,391,926, issued ~
July 9, 1968 t~ Per Arno Jaatinen, in which a top feeding system ;
is disclosed. A suction chamber is utilized in combination with
power driven wheels to enable the uppermost sheet to be driven
by the wheels in the direction of the ~orking machine where the
sheet is fed onto a conveying belt or other means. The suction
is not utilized to flatten warped board but rather, has the
obvious purpose of enabling the uppermost board to be drawn into
contact with the rotating wheels so that the board may be driven
laterally by the wheels. ``
Powered wheels have also been used in combination with
suction for alignment purposes as disclosed in U. S. Patent
3,677,537, issued July 18, 1372, to William C. Hawthorne. In
this case, the wheels or friction rollers 20 are axially dispos~
ed i~ the direction of the advancing sheet. The purpose of the
frlction ro~lers 20 is to power drive the sheet that is to be
advanced by feeder bar 32 to the desired aligmnent position
against side guide structure 36.
Despite many different utilizations of suction assist
techniques in the sheet feeding s-tate of the art, the efficiency
of all systems in use today leaves much to be desired. While `~
generally, the most efficient way of advancing sheets has been
the utilization of feed or kicker bar means,
_3_
1069948
there has been lacking an effective way of supporting the advancing
sheets whereby curling up of warped board and the like can be
~lattened while at the same time, the use of extreme suction,
which serves to diminish the effectiveness of ~he feeding
unit, can be avoided.
~.
Accordingly, it is an-object of the subject invention
to provide in corrugated blank feeding equipment, an improved
~eed bed and improved means of applying vacuum to advancing
blanks to enable maximum efficiency to be achieved.
It is a related object of the subjec~t invention to
provide an improved combination blank advancing means coupled
with improved feed bed means whereby advancing blanks which may
be warped may be held down or flattened to prevent jamming.
It is another object of the subject invention to
provide improved means of channeling vacuum against the lower- ~ -
most board to prevent warped boards from curling, leading to -
subsequent jamming.
It is an overall object of the subject invention to
provide improved operating efficiency in feeding blanks while
at the same time, preventing jamming which results in costly
down time.
It is yet another object of the subject invention to
provide a method and means of feeding blanks from the bottom
where friction between the board to be advanced and the remainder
of the stack of boards can be significantly reduced.
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It is still another ~bject of the subject invention to
provide structural improvements whereby higher vacuum can be
utilized to prevent warped boards from jamming without creating
friction problems with respect to the power necessary to drive
the boards forward to the processing machinery.
It is still another object of the subject invention to
provide structural modifications whereby blanks may be fed at a
substantially level plane to at least the close proximity of the
processing machinery.
It is a related object of the subject invention to
; provide improved kicker bar structure whereby the kicker bar need
not support the weight of the stack of boards causing the weight
e,D ,
of the stack to be shifted forwardly thus creating friction
problems for the advancing board.
It is yet another object of the subject invention to
provide means of creating vibration to lessen the friction be- ~
tween the stack of blanks and the advancing blank. ~;
It is a more specific object of the subject invention to
provide a method of advancing blanks and structural improvements
whereby a sliyht ripple is caused in the advancing sheet to create
air pockets between the stack of blanks and the advancing blank
to reduce friction.
According to the present invention there is provided an
apparatus for feeding blanks of sheet material to proc~ssing
machinery comprising: roller members axially positioned to rotate ~ ~
in the direction of travel of said blanks as said blanks are ~ -
moved to said processing machinery, said roller members serving as ~ -
-` a feed bed for supporting a stack of blanks and extending -
successively in the direction of travel of the blanks; hold down
means for said blanks including a vacuum source for providing
negative pressure to be applied substantially throughout the
space between said successive roller members against said lowermost
.. . .. .. .. .. .. .......
~6~69~
blank of said stack; means to move the lowermost blank of said
stack toward said processing machinery, and means for preventing
movement of all blanks but the lowermost blank of said stack
towards said processing machinery. The present invention also
provides a method of singularly feeding blanks from a stack into
processing machinery, comprising the steps of: supportiny said
stack of blanks on supporting elements of feed bed structure;
engaging the bottom blank of said stack with an advancing means
comprising at least one member along the side of said blank most r
remote from the processing machinery, said at least one member
being reciprocable toward and away from said processing machinery
along a path of travel which does not extend into a vertical
plane above said supporting elements; advancing the bottom blank
~ D
into the processing machinery and preventing movement of all the
blanks but the bottom blank towards said processing machinery;
keeping the surface area of the advancing blank flat during
advancement to the processing machinery during the time said
advancing blank is engaged by said advancing means; and, maintain- -
ing level guidance during advancement to the processing machinery
by utilizing air pressure against said advancing blank.
The present invention thu3 provides an improued
method of, and apparatus for, feeding sheets or blanks of
material from stacks is disclosed herein. ~he invention is '
utilized with processing machinery which performs operations such
as cutting, printing~ embossing and the like, the machinery
usually comprising a main frame with a feed platform at one end
thereof which supports a stack of the blanks to be fed F
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~6999L8
into the machine. There is included feeder bar means for
advancing the lowermost blank from the stack to a pair of pull
rolls which in turn a~vance each blank through the processing
machine.
In the improved apparatus of this invention, a vaccum
chamber is utilized in which there are disposed a plurality of
rotatable rollers axially mounted in a direction perpendicular
to the travel of the blanks of material. The mounting of the
rollers is critical to provide suction paths which effectively
hold down the sheet material during its travel which is
facilitated by the rotating rollers. In one embodiment, the
roller nearest the pull rolls and processing machinèry is to be
either larger than the other rollers or mounted with its center
line at a higher vertical position to create a favorable
pneumatic path in which warped blanks can effectively be
controlled to prevent jammin~. In another embodiment, the
rollers are placed at varying heights to create a ripple-like
effect in the advancing blank which helps to reduce friction
between that blank and the remainder of the stack.
An air cushioned kicker feed bar such as disclosed
in my U. S. Patent No. 3,675,918, issued July 11, 1972, may be
utilized to advance the single sheets to the feed rollers over
the rolling vaccum feed base herein disclosed. However, it is
preferable to mount the kicker feed bar with its pivotally ~
mounted plate member and feed clip depressed in relation to the `
feed -~
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rollers. This may be effectively accomplished by utilizing
alternating chambers of first a suction chamber with the feed
rollers followed by an empty chamber in which a feeding member
is positioned and so forth across the width of the machine.
By such structure, the stack of blanks and the advancing blank
may be maintained in a relatively horizontal position compared -
with prior designs where the kicker feed bar was mounted on top
of the feed bed causing the stack and advancing sheet to tilt.
The present invention will be illustrated by way of
10 the accompanying drawings in which:
Fig. 1 is a partial top view disclosing a rolling
~ .
vacuum feed bed in which an air cushioned kicker feed bar is
placed with its fingers in alternate strips across the width~
of the feed bed area;
Fig. 2 is a side sectional view taken along the lines
2-2 of Fig. l;
Fig. 3 is a cross sectional side view showing the
sheets being fed to the feed rolls on a feed bed which utilizes
an enlarged end roller and a vacuum relief valve;
Fig. 3A is a cross sectional side view similar to Fig. ~ r
3, however, which utilizes a modified vacuum relief valve;
Fig. 4 is a cross sectlonal end view taken along the
lines 4-4 of Fig. 3;
Fig. 5 is a cross sectional view of an end roller with
center line above the axis of remaining rollers;
Fig. 5A is a cross sectional view of a series of roll- -
ers with center lines of alternating rollers offset in the
manner of the roller of Fig. 5;
~ .
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~96~94~3
Fig. 6 is an end cross sectional view showing a
means for mountlng rollers in a feed table lay out where the
alternate strips of Fig. 1 are not utilized;
Fig. 7 is a cross sectional view taken along the lines -
7-7 of Fig. 6;
Fig. 8 is a schematic illustration of electrical
circuitry which may be utilized for the feeding system;
Fig. 9 is a side view of the type feed table of Fig.
1 in which an adjustable back stop is shown;
Fig. 10 is a side view of a modified back stop; and ~ ;
Fig. 11 is a partial plan view of the back stop and
feed table of Fig. 10.
With reference to Fig. 1, a preferred embodiment of
the feed bed is shown. Positioned across the width of the
machine are strip-like divisions to house alternating vacuum
; chamber strips 10 with feed advancing means disposed within the
remaining strip chambers 12 hereinafter referred to as feed
strips. The feed advancing means comprises a feed bar 14 which
extends widthwise across the feed bed and below the
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- ~69~L8
alternating vacuum chambers 10. Air cushioned kicker members
16 are shown mounted on the feed bar 14 and protrude upwardly
in each of the alternating feed strips 12 to engage the lower-
most sheet of the stack.
The feed bar 14 reciprocates by means of linkage
schematically shown by members 15 which are driven by drive
shaft 17 to produce the reciprocating movement. Thus, feed bar
14 reciprocates in the same manner as feeder bar 30 of my U. S.
Patent No. 3,709,483, issued January 9, 1973. ~ -
10Disposed between side walls 1~ of the vacuum chambers
10 are rollers 20 which are mounted so as to be freely rotatable
as will be described. A vacuum manifold 22 is shown as extend-
ing widthwise across the feed bed to provide suction capability
via orifices 24 which lead into each of the vacuum chambers 10.
The feed bed may comprise any number of strips such
-
as eight vacuum chambers 10 and one less number of feed strips
12. By control means (not shown) the vacuum supply to the
outer vacuum chambers may be turned off to conserve energy when ;-
small size blanks are processed which do not reach the outer
chambers when centered.
With reference to Fig. 2, a stack of blanks B are ;~
shown with the lowermost blank LB being advanced to the process-
ing equipment as will be described. A back stop member 26 whlch
need not be supported on the rollers 20 provides a guide for
the stack of blanks B and may comprise a single bar or a
plurality of individual members positioned along the width of
the feed table. Side guides (not shown) may also be utilized
~' .
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to maintain the alignment of the stack in a desired position
with respect to the processing equipment.
The air cushioned kicker feed assembly has been fully
described in my U. S. Paten~ No. 3,675,918 and utilizes a
feed bar 14 upon which is mounted actuator mechanism 28 which
may be identical to the actuator mechanism 59 disclosed in
the aorementioned patent. A piston projection 30 which is
the top portion of a piston (not shown) engages member 32
which is joined to rear roller 34 and overlies the piston
projection 30. This rear roller 34 engages plate member 36
of the spring inger which is pivotally mounted as shown at
38 on mounting member 40 which in turn is xigidly secured to
feeder bar 14. A feed clip 42 is mounted on the curved extremity
of plate member 36 and is the engaging means for each of the
feed fingers. While in principal, the air cushion f8eed assembly
operates as di~closed in my aforementioned patent~3,675J918
(as well as~Patent No. 3j709,483) it should be noted that the
mounting arrangement is different to improve the feed assembly's
. .
performance and permit its utilization in depressed araas
along the width of the feed bed. Thus, the plate member
36 is pivotally mounted on the inter~ediate block member 40 ~;
, and not directly on the feed bar 14.
`3 As shown in Fig. 3, on most standard processing
equipment, feed rolls 44 are utilized to draw the advanced
sheet into the equipment where the creasing, cutting, folding,
etc. takes place. A front gate 46, which is also standard,
is shown wh_-ch serve9 to pre~ent any sheets other than the
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~69~8
lowermost blank of material from being drawn into the feedrolls 44, since more than one blank would cause jamming. The
bottom and side walls of the vacuum chamber are shown as 48 and
50, respectively. Extension 52 to vacuum manifold 22 is shown
e~tending into chamber 12 to provide the vacuum source. It
will be noted that in this embodiment, the roller 54 which is
closest to the feed rolls 44 and the processing machinery is
enlarged in comparison to the other rollers. While roller 54
is shown enlarged, it may be identical in size to rollers 20
only have its center line raised in the manner as roller 70 is
shown in Fig. 5. Regardless of whether the end roller is
,
enlarged as roller 54 or raised as roller 70, it serves to l!`,
raise the level of the board as it approaches the feed rolls 44
and is advantageous in that it increases the suction effect
against warped boards and results in improved performance.
Below roller 54, a leaf-like vacuum relief deflection
member 56 is shown secured to the encl wall 50 by attachment
means 5~. This leaf-like member 56 may be a strip of ultra
high molecular weight (UHMW) material .020 inch thick which
; ,
terminates slightly beneath roller 54. When the suction is
applied and the lowermost blank LB is advanced, the deflection
member 56 serves as a valvable member so that when the blank `~
LB passes over the top of the rollers cutting off the vacuum
between the rollers, the increased vacuum will be applied to
pull the leaf-like member 56 downwardly to enable pressure
release.
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With reference to Fig. 3A, the end wall 50 of the
embodiment illustrated in Fig. 3 is replaced by a shortened
end wall 51 and a vertical leaf-like flexible member 57 which
may be constructed of spring steel and serves to prevent
the escape of vacuum at the front edge of the vacuum chamber.
With reference to Fig. 4, the construction and
moun~ing of roller 54 is show~ but it is to be understood
that this is the construction used as well for typical rollers r'~
designated 20. Thus, the rollers 54 may include a central
~J shaft 60 which is mounted at each extremity in antifriction
retainers 62 disposed along side walls 18 and positioned
on base member 48 of the vacuum housing. Bearings 68 support
the outer roller tube-like member 54 as shown with plate-like
thrust bearings 72 being positioned between bearings 68
and the retainer member 62. This outer tube-like member 54
may be constructed of stainless steel, plastic or suitable -
.
material.
~! With reference to Fig. 5, a cross section of a roller
is shown comprising the shaft 60 and outer roller member 70 ~ -
--:
with the center line of shaft 60 raised a distance of A ~;
over that of adjacent rollers 20. Thus, roller 70 may replace
roller 54 as the last roller in the embodiment of Fig. 3.
In place of the hollow rollers 30, 54, 70, solid
rollers 71, 73 as shown in Fig, 5A may be utilized. Further,
the alternating rollers 71 may be mounted with their center
lines positioned above the center lines of rollers 73 so
that the random rotating of the rollers will cause an eccentric
-l2-
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~ot6~9~8 -
path as the blank is advanced. In such a manner, a ripple
will be created along the advanclng blank LB producing air
pockets between the advancing blank LB and the succeeding
stack of blanks to minimize friction therebetween. While
not to'be deemed limiting, one in~h rollers may bé used with
alternating center lines .05 inches apart.
With reference to Figs. 6 and 7, an alternate embodiment -
is disclosed in which in place of the alternating strips of
rollers, the rollers extend widthwise across the feed bed.
As shown in Fig. 6, bottom vacuum chamber wall 74 supports
anti-friction retaining members 76 which are positioned a~
intervals along the width of the machine. Hollow rollers 78
secured to solid end walls 80 may be utilized with pins 82
being rotatably mounted in the retaining members 76. Tube '
member 84 leads from the vac~um source to the vacuum chamber
formed by members 74, 75, ~.
The positioning of the rollers 78 of Fig. 6 is shown
in Fig. 7 and as few as three roll'ers may be utilized to provide -
support for the advancing blank LB. It can be ~isualized in
Fig, 7 tha~ a warped blank with a curled end C may be in-
fluenced by the suction as shown in phantom so that the end
C is brought down or flattened to'clear the front gate 46
as shown. '
In the embodiment of Figs. 6 and 7, the feed'bar 14
wi.th the kicker member 16 may either be depressed and to
the left of the rollers 78 (see Fig. 7) or in the alternative
' -13-
~69~
positioned in a plane above the rollers 78 or directly above ~,
the ro~lers 78 assuming there are additional rollers to the
series of ~hree shown in Fig. 7.
A suitable type of circuitry such as shown in Fig. 8
may be utilized to provide a skip-feed operation as disclosed
~,S.
,in my aforementLoned~Patent No. 3,~75,918. A suitable source
of positive pressure 86 supplies each of the kicker actuator
assembly mechanisms 28 through line 88 which passes through , ,~
valve member 90. The valve may be controlled by a solenoid
92 from which control leads 94 and 96 extend to power line ,
ter~inals 98 and 100 respectively when the feed control switch ,,
102 is in its "regular f~ed" position as shown in Fi8. 9
The feed control switch 102 has two other positions, ~;~
i.e., those shown in phantom with the switch at switch contact
104 for the off position and 106 for the "skip position". In
the off position, since ~he c,onnection between power line
terminal 98 and the control lead 94 is opened, the solenoid
92 is deactuated and the valve 90 closed with the feed bar , ~ ,
14 remaining deactuated.
In the "skip position" the terminal 98 is connected
to control lead 94 by way of control terminals 108 and 110
of flip-10p relay 112 of a commercially-availa~le stable
state type. The flip-flop relay 112 includes a pair of
control terminal,s, 114 and 116 so~that a control pulse
supplied between these terminals Ls effective to change the
flip-flop relay from either of its conduction states to the other
and the next subsequent pulse,is operated to flip the relay
back to its first conduction state. These control terminals
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1~6~9gL8
114 and 116 are connected between power line terminals 98 and
100, with terminal 116 being connec-ted directly to terminal 100
while control terminal 114 is connected to power line terminal
98 through the impulse switch sensor 118 and the switch when it -~
is set at contact 106 or is in its "skip" position. When the
machine is operating a control pulse is applied between the
relay control terminals 114 and 116 each time the impulse switch
sensor 118 is closed. This switch sensor 118 is closed when the
feed bar 14 moves forward during its normal cycle of operation.
When the feed control switch 102 is in its "skip" position ;
current will be supplied through flip-flop relay 112 to hold
the valve 90 open during a given cycle of operation of the feed ~ ~ ;
bar 14. The operation of the feed bar 14 will then close the
impulse switch sensor 118 thereby to apply a control pulse
between control terminals 114 and 116 of relay 112 and change
it to a non-conductive state. During the successive cycle of
., .
operation of the feed bar 14, no current will be supplied to ~;
valve 90 and accordingly, valve 90 will be closed so that` the
actuator mechanisms 28 will be deactuated. During the next
stroke of feed bar 14 the impulse switch sensor 118 will agaln
be ope~rated and will cause a voltage pulse to be applied between
control terminals 114 and 116 of the relay 112 to return the
flip-flop re]ay to a high-conduction state, thus opening
solenoid valve 90 and reactuating the actuator mechanism 28
so as to feed the next subsequent sheet into the feed rolls 44.
~.
.: :
With reference to Fig. 9, back stop members 120 having
rotatable guide rollers 122 positioned across the width of ~
each back stop member 120 are used to provide the rear support '
against which ~he blanks B are positioned. Thus, the blanks
will normally be positioned in the hopper type arrangement
between back stop 120 and the front gate structure 46 (see
Fig. 3) and further secured between side-gates (not shown~. ; -
A back stop member 120 may be provided above each of the vacuum
~ : -
chambers 10 which extend along widthwise across the machine
as shown in the embodiment of Fig. 1. The back stop members
120 are joined by plate member 123 which extends widthwise `
across the machine and which may be provided with means to
secure the plate members 123 and back stop members 120
firmly in place. In the particular arrangement disclosed in
Fig. 9, the vacuum access means leading to the chamber below
xoller 20 is designated as 124 and is positioned forward of
the probable positioning of the back stop 120.
It is to be noted that the back stop member 120 is ~ -
adjustable and may be slid forward or to the rear along the
roller members 20 as required to accommodate blanks of different
:: ;::.
sizes. The back stop member may also be provided with a ,
vacuum close-of~ member 126 which as shown in Fig. 9, is
lowered to within the chamber to restrict the vacuum to that
portion of the chamber above which blanks are being transported.
As shown, vacuum close-off member 126 may be a plate-like
member ex~ending widthwise across the chamber and having a
handle 128 which also serves as a locking member when the close~
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~LOG994!3
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off member 126 is positioned in its position of non- use, as
shown in phantom in Fig. 9. The vacuum close off member
126 may also be utilized as a stop or locking member to
prevent movement of the back stop assembly during operation.
Automation me~ns may be utilized to control the vacuum close-
off member 126.
With respect to Fig. 10, modified back stop members
]30 are provided each having a blank positioning roller 122
as disclosed in the embodiment of Fig 9. The back stop
assembly which includes multiple back stop members 130 also
includeæ widthwise member 131 which extends across the machine
as shown in Fig. 11. In place of the vertical close off
member 126, an extendable roll~out curtain member 132 such
as an industrial window shade is shown in Fi.gs. 10 and 11 as
being extended from its storage roll 134. A handle type
; member 136 may be utilized or in the alternative, automation
means may-be provided to extend the roll-out curtain member
132 as desired. Thus,- in the embodiment of Figs. 10 and 11,
the access 138 to the vacuum chamber from the vacuum manifold
may be positioned a~ any place along~the chamber 10 to provide ;
the negative pressure without regard to the positioning of
back stop member 130. The roll-out curtain member 132 serves
to prevent the loss of pressure through the rollers 20 which
are not in use when blanks of a small size are being processed
at the time the back stop 130 is positioned in a forward position.
The roll out curtain member may be constructed of light gage
spring steel or from plastics,such as reinforced nylon.
17-
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~ 6~ 8
: ,:
Thus, when large blanks are being processed, the back
stop members 120, or 130, will be positioned as far to the
left as is necessary to position the blanks B on the rollers.
Corresponding adjustments will be made to feed bar 14 and the
machine will be placed on a skip-feed setting. The air
cushioned kicker eed bar assembly ensures a positive gripping
action of each of the kicker members 16 during the feeding
operation to minimize the possibility of malfunction. The
vacuum chambers whether in alternating position such as
chambers lO of Fig. 1 or of the widthwise construction dis-
closed in Fig. 7 provide sufficient negative pressure to hold
down at least the forward portion of the advancing blank LB
to ensure that it is properly received by the feed rolls 44.
When small blanks are processed the back stop members
].20, 130 are adjusted to the right as necessary.
In the embodiment generally shown in Figs. l and 2,
the depressed position of the kicker feed bar 14 and its kicker
members 16 permits the stack of blanks to be retained in a
horizontal 1at position substantia1ly as shown in Fig. 3.
This is essentially truP despite the use of an enlarged
roller 54 or a raised roller 70 at the proximi~y of the front
gates 46. In addition, the horizontal position as contrasted
; to an inclined position is maintained despite the use of
rollers 71 and 73 as shown in Fig. 5A which are utilized .
to provide an eccentric path for the advancing blank LB.
Thus, in this embodiment of Fig~s.l and 2, the feed bar l~
is not positioned on the top p:E the feed bed as in conventional
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~36~8
.
sheet feeding systems and which causes the sheet to be not
fed in a flat plane but always dimensionally in a fore
shortened plane and never in per~ect register with.subsequent
machine cycle. However, in the embodiment of Figs. 1 and 2, wi~h
the feed bar 14 depressed as shown in Fig. 2, only the air ~:
cushion kicker members 16 protrude in alternate strips
and the blank may be fed in a flat plane to the feed rolls
In the embodiments of Figs. 3 and 5, by raising the
roller surface beneath the gates 46 by either enlarged roller
member 54 or the roller 70 whose center line is raised,
the lead edge of the advancing blank seeks a definite reference
point permitting the sheets to be. fed free of jam-ups. This
advance roller is preferably.positioned at least partly under .
the front gate 46 and when the sheet has a small curl on its
lead edge, it is extremely difficult to flatten even with
high vacuum when the en~ire bed is in a flat plane. :~
The use of the rolling vacuum eed table described ~ - ;
herein allows ~he utilization of much higher vacuum than used ~ ~
on most systems such as 100" of ~2 to ensure that warped ~.
sheets are brought down to a flat plane elminating the problem
of previous systems whereby an increase of vacuum would create
friction between the blanks and the table to the extent that
~he kicker device could not push the blank into the feed
rolls 44. Thus, the rollers 20 which are shown as being
freeIy rotatable, but ~hich could conceivably be power driven
.
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~6~948
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in register with the feed bar 14 serve to.eliminate the
friction which was a cause of jam-ups previously.
It will be readily appreciated that the entire feed
bed construction shown in Figs. 1 and 2 may be utilized to
replace the feed bed of an existing machine or in the
alternative, the standard perforated plate feed bed commonly .
in use in industry today may be replaced by the chamber-like ~::
construction shown in Figs. 6 and 7. In the latter situation,
the kicker bar assembly of the existing machine may be utilized. : : .
While it is preferable to use the air cushioned feed bar
kicker assembly, other kicker bar structures may also be
advantageously used with the rolling vacuum feed table.
While various embodiments of the :invention have
been shown and described, it will be understood that other
modifications may be made. The appended claims, therefore, ::
are intended to define the true sco~e of the invention.
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