Note: Descriptions are shown in the official language in which they were submitted.
10~2563
The present invention relates to apparatus for
introducing stacks of paper sheets or the like into containers,
e.g., into boxes made of thick paper, cardboard or similar
material.
It is already known to fill containers (hereinafter
called boxes for short) in an apparatus wherein a receptacle for
stacks of paper sheets has an open side for introduction of stacks
into its interior and is vertically movable between a raised
position in which it receives a stack of sheets from a suitahle
conveyor or the like and a lower position in which it is ready to
dischaxge its contents into a box therebelow. A.s a rule, the ~
conveyor which supplies stacks delivers successive stacks into a ~ -
position of abutment with a stop, whereupon a pusher transfers -
the arrested stack into the receptacle. The bottom of the
receptacle consists of two flaps which are pivotably secured to
the respective side walls and can be moved between substantially
horizontal positions in which they support the stack from helow
and substantially vertical positions in which they extend into
the interior of an empty box when the receptacle is moved to its
lower position. The flaps constitute a gate and further serve
to guide the descending stack into the interior of the box which
is located below and registers with the receptacle.
A drawback of the just described apparatus is that it
cannot be used for introduction of stacks into boxes which are
dimensioned to receive the stacks without any or with negligible ;
clearance. Furthermore, many types of boxes are rather unstable
and tend to undergo pronounced deformation during introduction of
stacks. If the side walls of the boxes are deformable, such side
walls tend to bulge outwardly during introduction of stacks
whereby the upstanding corners of the box move inwardly and prevent
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1~9~563
the corners of the stack from entering the box. The flaps reduce
the likelihood of excessive bulging of at least two side walls ~
because they extend into the interior of the box below the -
.
receptacle. However, they interfere with immediate removal of
a filled box from a position of register with the receptacle.
Furthermore, the receptacle cannot receive a fresh stack prior to
return movement to raised position to thereby extract the flaps
from the filled box therebelow and prior to subsequent pivoting -
of the flaps back to their normal stack-supportingpositions. The -
filled box can be replaced with an empty box when the receptacle
is raised and its flaps returned to stack-supporting positions.
Therefore, the output of the just described apparatus cannotbe
increased to the extent which is necessary to warrant economic
operation of a modern production line wherein the sheets are
severed and stacked at an extremely high speed.
The invention is embodied in an apparatus for
introducing stacks of sheets or the like into containers. The
apparatus comprises a receptacle which serves for temporary
; storage of stacks and has a bottom including a plurality of
sections movable between first positions in which the sections
provide a base for the lowermost sheet of a stack in the
receptacle and retracted positions in which the stack is free
to descend by gravity, means for feeding stacks into the
receptacle, a support for containers below the receptacle, means
for delivering empty containers onto the support, one after the `
other, to a position of register with the receptacle, means for
removing filled containers from the support, and means for
simultaneously moving the sectionsof the bottom from the first
positions to the retracted positions whiIe the receptaclecontains
a stack and an empty container on the support registers with the
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iO9;~563
receptacle.
In accordance with a presently preferred embodiment,
the bottom comprises two sections which are movable toward and
away from each other. Such sections are preferably coplanar or
substantially coplanar in each of their positions.
The novel features which are considered as character-
istic of the invention are set forth in particularin the appended
claims. The improved apparatus itself, however, both as to its
construction and its mode of operation, together with additional
features and advantages thereof, will he best understood upon
perusal of the following detailed description of certain specific
embodiments with reference to the accompanying drawing.
FIG. 1 is a plan view of an apparatus which embodies
one form of the invention;
FIG. 2 is a vertical sectional view as seen in the
direction of arrows from the line II-II of FIG. l;
FIG. 3 is a sectional view as seen in the direction of
arrows from the line III-III of FIG. 2;
FIG. 4 is a plan view of a second apparatus;
FIG. 5 is a vertical sectional view as seen in the
direction of arrows from the line V-V of FIG. 4;
FIG. 6 is a sectional view as seen in the direction of
arrows from the line VI-VI of FIG. 5;
FIG. 7 is an enlarged fragmentary sectional view of a
modified bottom section which can be utilized in the receptacle
of the apparatus of FIGS. 1-3 or 4-6; and
FIG. 8 is a similar enlarged fragmentary sectional view
of a different bottom section. ~ -
The apparatus of FIGS. 1-3 comprises a stationary
receptacle 1 for stacks 2 of paper sheets which are to be
~:
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1092S~3
transferred into empty containers 6 ~e.g., boxes made of
cardboard or the like). The means for feeding successive stacks
2 to the receptacle 1 comprises a conveyor 3 which transports the
stacks 2 in the direction indicated by arrow A ~see FIG. 3). The
receptacle l is located at a level above a second receptacle 4
which comprises a stationary support or platform 37 for boxes 6.
An endless chain or belt conveyor 7 serves to deliver empty boxes
6 to the receptacle 4, and a further endless belt or chain
conveyor 8 serves to receive filled boxes 6' from the receptacle
4. The conveyor 7 is in line with the conveyor 8 and the platform
37 of the receptacle 4 is located between these conveyors. ~.
The second receptacle 4 further comprises an advancing
and locating unit 9 for empty boxes 6; the purpose of this unit
is to insure that an empty box 6 on the platform 37 is`in a ~ -
position of exact or nearly exact register with the receptacle 1. -
.:
The moving parts are connected with a drive 11, preferably a ~ -
variable speed transmission, which is mounted in or on the main
frame 12 of the apparatus. The transmission 11 receives torque
from a main prime mover in a production line which includes the
improved apparatus.
The first receptacle 1 comprises a stationary upright
end wall 13 and has an open side which is located opposite the
end wall 13 and allows for admission of stacks 2 which are fed
by the conveyor 3. A stack 2 is properly introduced into the
receptacle 1 when its front end face abuts against the end wall
13. The receptacle 1 further comprises a novel and improved
bottom which resembles a door with a plurality of slidable panels
or sections. The bottom of the receptacle 1 comprises two
~ 30 sections 14a and 14b which can perform translatory movements
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toward and away from each other between first positions which
are shown in FIGS. 1 and 2 and in which their panels 16a, 16b
constitute a base or table for a stack 2 in the receptacle 1, -
and second or retracted positions in which the panels 16a, 16b
are spaced apart to establish a gap which is wider than the
corresponding dimension of a stack 2 so that the latter can
descend by gravity into an empty box 6 on the platform 37 of the
second receptacle 4. As shown in FIG. 2, the panels 16a, 16b
are substantially but not exactly coplanar; this cuases the
median portion of a stack 2 in the receptacle 1 to bulge downward-
ly and to assume a substantially V-shaped configuration. Such
mounting of the panels 16a, 16b is often desirable because it
renders it possible to properly fill a box 6 which is not in
exact alinement with the receptacle 1. The sheets of the
descending stack 2 slide along one wall of the box 6 in fanwise
fashion and find their way into the box, even in the absence of
exact registry between 1 and 6. Furthermore, the central portion ~- .
of the descending stack 2 expels air from the center toward the
side walls of the box 6 therebelow and enables such air to escape ~: -
from the box while the latter is in the process of receiving the
stack.
The sections 14a, 14b of the bottom of the receptacle
1 further comprise upstanding portions 17a, 17b which constitute
two side walls of the receptacle 1 and flank the end wall 13 when
the sections 14a, 14b assume the first positions which are shown : :
in FIe. 2. In such positions of the sections 14a and 14b, the
panels 16a, 16b constitute the bottom, the wall 13 constitutes one :
end wall, and the portions 17a, 17b constitute two side walls of
the receptacle 1. The other end wall is absent to provide the ~
aforementioned opening for introduction of successive stacks 2. ~ :
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~09Z563
Those parts of the side walls 17a, 17b which are nearest to the
conveyor 3 flare outwardly to form a convergent inlet for
admission of stacks 2 into the receptacle 1.
The means for moving the sections 14a, 14b hetween
first and second or retracted positions comprises two motors each
of which preferably constitutes a fluid-operated (most preferably ,!
pneumatic) cylinder and piston unit. The drawing shows two piston
rods 18a, 18b which are respectively connected with the sections
14a, 14b and are further connected to pistons (not shown) in
double-acting cylinders l9a, l9b mounted in the frame 12. The
chambers of the cylinders l9a, l9b are connected with a
solenoid-operated valve 23 by conduits 21 and 22 in such a way
that they move the sections 14a, 14b toward each other when they
receive compressed fluid via conduits 21 and that they abruptly
retract the sections 14a, 14b in response to admission of
compressed fluid via conduits 22. The conduits 21 then
communicate with the atmosphere. The source of compressed fluid
is shown at 24. The valve 23 is actuated in synchronism with
movements of various conveyors of the apparatus and with moving
parts of other units of the production line to effect abrupt
retraction of the sections 14a, 14b when the receptacle 1
accommodates a stack 2 and the platform ~7 supports an empty box
6 below the receptacle 1, and to immediately return the sections
14a, 14b to first positions as soon as the stack 2 has descended
from the receptacle 1 into the box 6 therebelow. The means for
actuating the valve 23 comprises a control unit 26 which is
connected thereto by conductor means 25. The control unit 26
may comprise a conventional pulse generator including a disk
which is driven by the transmission 11 or by the main prime mover
of the production line and has one or more magnets which travel
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1092563
past a proximity detector whose output is connected with the
valve 23 via conductor means 25.
The feeding conveyor 3 is an endless conveyor which
comprises several endless belts 29 disposed in parallel vertical
planes and trained over pulleys 27, 28. The manner in which the
stacks 2 are delivered to the upper reaches of the belts 29 forms
no part of the present invention. The belts 2~ are continuously ~ -
driven by the pulley 27 which receives torque from the transmis~
sion 11. This is indicated by a phantom line llA which is shown
in FIG. 3.
The discharge end of the conveyor 3 is not immediately
adjacent to the open end of the receptacle 1. As shown in FIG.
3, successive stacks 2 must advance along the upper side of a
horizontal bridge 30 which is mounted in the frame 12 and extends ~-
between the pulley 27 and that end of the receptacle 1 which is
remote from the end wall 13. The means for transporting succes- ~ -
sive stacks from the discharge end of the feeding conveyor 3 into
the receptacle 1 comprises a transfer conveyor 31 having a first
pair of endless chains 32a at one side of the bridge 30 and a
second pair of endless chains 32b at the other side of the bridge.
The upper chain 32a is disposed in a common horizontal plane with ~ ~;
the upper chain 32b, and the lower chain 32a is disposed in a
common horizontal plane with the lower chain 32b. These chains
are respectively trained over sprocket wheels 33a, 34a and 33b,
34b. The chai~ 32a are connected to each other by a vertical
entraining element 36a, and the chains 32b are connected to each
other by a vertical entraining element 36b. These entraining
elements are disposed in a common vertical plane which extends ~ -
transversely of the path of stacks 2 on the feeding conveyor 3.
Thus, when the entraining elements 36a, 36b approach each other
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~09~563
while moving around the rear sprocket wheels 34a, 34b, they
engage the rear side of a stack 2 on the belts 29 and push the
stack over the bridge 30 and into the receptacle 1. The elements
36a, 36b then move away from each other while travelling around
the front sprocket wheels 33a, 33b and thereupon move rearwardly
toward the sprocket wheels 34a, 34b with the outer stretches of
the respective chains 32a, 32b. ;
The means for driving the transfer conveyor 31 is
indicated by the phantom line llB. As shown in FIG. 3 for the
sprocket wheels 34b, the sprocket wheels 34a and 34b receive
torque from the pulley 27 for the belts 29. The operative
connections may include shafts, bevel gears and similar conven-
tional torque transmitting elements.
The lower receptacle 4 comprises the aforementioned
platform or support 37 and two side walls which are spaced apart
by a distance corresponding to the width of a box 6. One of these
side walls is the lower portion of the end wall 13 of the upper
receptacle 1, and the other side wall of the receptacle 4 is
shown at 38. The wall 38 is stationary, the same as the wall 13.
It is clear that the wall 13 can be replaced with two discrete
walls one of which constitutes the end wall of the receptacle 1
and the other of which constitues one side wall of the receptacle
4.
The aforementioned advancing and locating unit 9 is
arranged to move stepwise or continuously between a front end
position (shown in FIG. 2) and a rear end position. This unit
comprises a carriage 43 which is mounted on wheels 41 guided ~y
rails 42 which are mounted in the main frame 12. The rails 42
extend at right angles to the direction of travel of stacks 2 on
the belts 29 of the feeding conveyor 3. The carriage 43 is
1092563
provided with pivotable pushers 46 which are secured thereto by
shafts 44 and can move between the upright positions shown in FIG.
1 and horizontal positions in which thev are located at a level
below the platform 37. The latter is formed with suitable slots
37A to allow for pivoting of pushers 46 between upright and
horizontal positions. The mechanisms which cause the pushers to
move betweèn their end positions are schematically indicated at
45; however, the exact nature of such mechanisms forms no part of
the invention. For example, each such mechanism may comprise a
rotary electromagnet which is energized or deenergized by limit
switches which are adjacent to the path of movement of the
carriage 43 and are actuatable by trips on the carriage to cause -~
the pushers 46 to rise or descend in predetermined position~s of
the carriage.
The means for moving the carriage 43 back and forth
comprises a crank drive 47 which derives motion from the trans- ~ ~
mission 11 and a link 48 which is articulately connected to the `
carriage. The purpose of the carriage 43 is to accept emptv hoxes
; 6 from the delivering conveyor 7, to locate such empty boxes
below the receptacle 1 prior to movement of the sections 14a, 14b
to retracted positions, and to transfer filled boxes 6' onto the
receiving conveyor 8.
As mentioned above, the transmission 11 can be driven
by the main prime mover of the production line which embodies the
apparatus of FIGS. 1 to 3. Such production line can sever large
sheets of paper lengthwise and crosswise to form blanks or
smaller sheets of desired size, and the blanks are thereupon
stacked prior to delivery into the range of the feeding conveyor ;
3. The conveyor 8 can deliver filled boxes 6' to a station where - ~-
the boxes are provided with covers or to another destination.
-- 10 --
lO9ZS~;3
The unit 9 can be said to form part of a composite
means for delivering empty boxes 6 to a position of register with
the receptacle 1. By the same token, the unit 9 can be said to
form part of a composite receiving means which further includes
the conveyor 8. The side walls 13, 38 of the receptacle 4 define
an elongated path along which empty and filled boxes 6 and 6' can
advance from the conveyor 7 onto the conveyor 8.
The operation: -
The transfer conveyor 31 is in the process of advancing
a fresh stack 2 into the receptacle 1 (see particularly FIG. 3),
and the carriage 43 maintains an empty box 6 in a position of
register with the receptacle 1, i.e., below the sections 14a, 14b
which are held in their first positions. As the conveyor 31
continues to advance the stack 2 into the receptacle 1 (i.e.,
toward abutment with the wall 13), the mechanisms45 cause the
pushers 46 to pivot to a level below the platform 37 so that the
carriage 43 is free to move backwards without shifting the
properly positioned empty box 6 which rests on the platform 37.
The pushers 46 are erected again when the front pushers are
located behind the box 6 on the platform 37 and when the rear
pushers are located behind the foremost empty box 6 on the
delivery conveyor 7.
The stack 2 which is pushed over the bridge 30 reaches
the end wall 13 when the entraining elements 36a, 36b begin to
travel around the front sprocket wheels 33a, 33b of the transfer
conveyor 31. The control unit 36 then transmits a signal which
causes the valve 23 to admit compressed fluid into the conduits
22 and to connect the conduits 21 with the atmosphere. The
pistons in the cylinders l9a, l9b cause the respective piston rods
18a, 18b to abruptly retract the sections 14a, 14b whereby the
-- 11 --
1092S63
panels 16a, 16b slide from below the lowermost sheet of the stack
2 in the receptacle 1 and allow the stack to descend by gravity
into the empty box 6 on the platform 37. The carriage 43 there-
upon moves forwardly and its front pushers 46 advance the filled
box 6' along the platform 37 and onto the receiving conveyor 8.
At the same time, the rear pushers 46 of the carriage 43 advance
the foremost empty box 6 from the delivery conveyor 7 onto the
platform 37. The walls 13 and 38 of the lower receptacle 4 are ;
adjacent to the outer sides of two side walls of the box 6 on the
platform 37 so that such side walls of the box cannot bulge
outwardly during entry of a stack 2. The other two walls of the
box 6 are assumed to be twin walls so that they are less likely
to bulge outwardly during introduction of a stack. Furthermore,
by properly propping two side walls, the likelihood that the
other two walls of the box 6 will or might undergo pronounced
deformation during admission of a stack 2 is very remote.
The solenoid of the valve 23 is deenergized immediately
after the stack 2 descends into the box 6 on the platform 37.
Thus, the sections 14a, 14b reassume the positions of FIG. 1 and
the receptacle 1 is ready to receive the next stack 2. Such ;
stack is delivered by the transfer conveyor 31 in the same way
as described above. The sections 14a, 14b can be moved apart as
soon as the oncoming stack 2 reaches the end wall 13 of the upper
receptacle 1. As mentioned above, the movements of all conveyors
are synchronized with movements of the carriage 43, pushers 46 ~ -
and sections 14a, 14b to insure that the length of intervals -
between filling of successive boxes 6 depends primarily on the
length of that interval which is required for gravitational
descent of a stack 2 from the receptacle 1 into a box 6 on the
platform 37.
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1092563
The apparatus of FIGS. 1-3 is susceptible of many
modifications without departing from the spirit of the invention.
For example, the transfer conveyor can be omitted if the discharge -
end of the conveyor 3 extends all the way to the open side of the
receptacle 1 so that the conveyor 3 can advance stacks 2 into
abutment with the end wall 13. Furthermore, the advancing and
locating means 9 can be replaced with an endless conveyor with
pushers which descend to a level below the upper reach of the
conveyor 8 as soon as they complete the delivery of a filled
container 6' and rise above the upper reach of the conveyor 7
when they return to a position behind the foremost empty box 6
on the conveyor 7. Still further, the end wall 13 can be omitted
if thè conveyor 3 or 31 is designed to advance successive stacks
2 to a predetermined position of accurate register with an empty
box 6 on the platform 37. Also, the conveyors 7 and 8 need not
transport empty and filled boxes in a direction at right angIes
to the direction of transport of stacks 2 on the conveyor 3.
The output of the apparatus of FIGS. 1-3 greatly exceeds
the output of the aforediscussed conventional apparatus. It has
been found that the apparatus of FIGS. 1-3 is especially suited
for boxing or crating of stacks which consist of relatively small
sheets, leaves or plates. Problems could arise when the sheets,
leaves or plates are relatively large, e.g., corresponding in size
to German DIN A 1 or DIN A O norms. Such problems develop mainly
during movement of the bottom sections to their retracted
positions because the orientation of relatively large sheets,
leaves or plates (hereinafter called sheets) is likely to change
during gravitational descent into an empty container or box below
the first receptacle. One of the reasons for such change in
orientation is that the flexibility of a relatively large stack
- 13 -
lO9ZS~;3
:
(namely, a stack consisting of leaves having a pronounced length
and/or width) greatly exceeds the flexibility of a relatively
compact stack consisting of overlapping sheets having a relativelv
small width and/or length. In order to ade~uately support the
lowermost sheet of a stack of large leaves, the sections of the
bottom must constitute a large table which presents a practically
continuous upper surface for the lowermost sheet of the stack.
Consequently, the sections must cover a substantial distance
during movement to retracted positions wherehy the median portion
of the stack of large sheets begins to bulge downwardly as the
width of the gap beteeen the sections increases. In other words,
the median portion of the lowermost large sheet forms a loop while
the marginal portions of the lowermost sheet still contact the
respective sections during movement of sections to their retracted
positions. Moreover, the upper layer of the stack exhibits a
tendency to roll while the median portion of the stack bulges ;
downwardly in the gap between the sections during movement of
sections to their retracted positions. This, in turn, prevents
the stack from descending into the box therebelow in the form of a
solid block-shaped body or slab, i.e., certain sheets (especially
the uppermost sheets) exhibit a tendency to come to rest by
abutting with one of their major sides against a side wall of the
box.
The just discussed problems can be avoided by resorting
to an apparatus which is shown in FIGS. 4-6. All such components
of this apparatus which are identical with or clearly analogous
to corresponding components of the first apparatus are denoted by
similar reference characters plus 109 and are not described again.
One of the main differences between the apparatus of
FIGS. 1-3 and 4-6 is that the panels 116a, 116b of the sections
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lO9Z~
114a, 114b comprise downwardly extending guide portions in the
form of vertical or substantially vertical plates or strips 115a,
115b which are parallel or nearly parallel to each other and are
relatively thin, at least in the region of their lower ends which
are remote from the lowermost sheet of a stack 102 in the
receptacle 101. The sheets of the stack 102 are assumed to be
relatively long and/or wide so that the stack 102 is readily
flexible, especially if its sheets consist of relatively thin
paper. The guide portions or strips 115a, 115b need not be very
long, as considered in a direction toward the open upper end of
a box 106 below the receptacle 101.
The apparatus of FIGS. 4-6 further comprises two
arresting devices 125a, 125b which are respectively located in
the paths of movement of the sections 114a, 114b to their retracted
positions and serve to arrest the sections when the strips 115a,
115b are located at a predetermined distance from each other,
namely, at a distance which equals or approximates the width or
length of sheets constituting a stack 102. The arresting devices
115a, 115b are secured to the end wall 113, preferablv in such a
way that they can be adjusted in order to conform the maximum
distance between the strips 115a, 115b to the width or length of
sheets of successively supplied stacks 102. To this end, the end
wall 113 may be formed with several sets of tapped bores (not
specifically shown) for the screws or bolts 125aa, 125bb which
secure the respective arresting devices 125a, 125b to the end
wall 113.
The second receptacle 104 has two parallel side walls
138 which extend upwardly from the support 137 and define a space
having a width corresponding to that of a box 106. The rails 142
for the carriage 143 are mounted in a frame member 151 which is
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1o~2~63
movable up and down in the main frame 112 in directions indicated
by the double-headed arrow 152. The frame member 151 forms part
of means for varying the distance between the support 137 and the
receptacle 101, and such means further includes a mechanism for
moving the frame member 151 up and down. The mechanism includes
a crank drive having a link 153 which is articulately connected to ~ ~
the frame member 151 and receives motion from the transmission 111. ~ -
The operation of the apparatus of FI~S. 4 to 6 is .
analogous to that of the first apparatus. The transfer conveyor
131 is shown in the process of delivering a stack 102 into the ~ ~
receptacle 101, and the advancing and locating unit 109 maintains ~ -
an empty box 106 in register with the receptacle 101, i.e., such
box is located in the second receptacle 104. As the stack 102
advances toward the end wall 113, the carriage 143 of the unit
~: .
109 is moved rearwardly under the action of the crank drive 147
and the pushers 146 are caused to pivot counterclockwise, as ~-
viewed in FIG. 5, and to reassume their erected positions when
the left-hand pushers are located behind the empty box 106 below
the receptacle 101 and the right-hand pushers are located behind
the foremost empty box 106 on the delivering conveyor 107. The
frame member 151 is thereupon lifted by the link 153 to such an
extent that the lower end portions of the strips 115a, 115b are
close to or extend into the open top of the box 106 on the support
137. In the-meantime, the stack 102 reaches the end wall 113 -
whereupon the control unit 126 energizes the solenoid of the
valve 123, i.e., the pistons in the cylinders ll9a, ll9b cause -~
the respective piston rods 118a, 118b to abruptly move the ;;
sections 114a, 114b of the bottom of the receptacle 101 to
retracted positions, namely, into abutment with the arresting
devices 125a, 125b. The lower end portions of or the entire ~- -
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~0~2563
strips 115a, 115b come into contact with the respective inner
surfaces of the empty box 106 on the support 137. This insures
that the box 106 is properly oriented with respect to the
receptacle 101 and that it is not unduly deformed, i.e., that
its open top permits the descending stack 102 to enter the box
in an optimum position. During such downward movement, two sides
of the descending stack 102 are guided by the inner surfaces of
the strips 115a, 115b, i.e., the strips 115a, 115b constitute a
duct wherein the stack 102 descends. In the next step, the link
153 returns the frame member 151 to the lower end position, i.e.,
the distance between the receptacle 101 and the support 137 is
increased. This moves the filled box 106' into register with the
receiving conveyor 108 and the crank drive 147 thereupon causes
the carriage 143 to advance the filled box 106' onto the conveyor
108 while simultaneously advancing the foremost empty box 106 --
,
into register with the receptacle 101.
The sections 114a, 114b move toward each other in
response to deenergization of the solenoid of the valve 123
immediately after the frame member 151 assumes its lower end
~, . . .
position or as soon as this frame member assumes an intermediate
position in which the strips 115a, 115b are located at a level
above the freshly filled box 106'. Thus, the receptacle 101 is
ready to accept the next stack 102 which is delivered by the
transfer conveyor 131.
The apparatus of FIGS. 1-3 or FIGS. 4-6 can be modified
by omitting the conveyors 3, 31 or 103, 131 and by accumulating -~
the stacks 2 or 102 directly in the receptacle 1 or 101. In
other words, the panels 16a, 16b or 116a, 116b then form a table
on which a succession of sheets acc~ates to form a stack which
is thereupon caused to descend onto the support 37 or 137 in
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response to movement of sections 14a, 14b or 114a, 114b to their
retracted positions. The conveyors 3, 31 or 103, 131 are then
replaced with other conveyor means which can deliver discrete
sheets, or smaller groups of sheets, directly into the receptacle
1 or 101. In such apparatus, the receptacle 1 or 101 need not
have an open side opposite the end wall 13 or 113 because discrete
sheets or smaller groups of sheets can be supplied from above. ~;
Friction between the lowermost sheet of a relatively
compact stack (namely, a stack which consists of relatively small --
sheets) and the upper surfaces of panels 16a, 16b or 116a, 116b
is not sufficiently pronounced to interfere with retraction of
the sections 14a, 14b or 114a, 114b. However, when the stack
consists of relatively large (long and/or wide) sheets, and the
stack is rather high, friction could result in lateral shifting
of or damage to the lowermost sheet of the stack. In such
apparatus, one or both panels of the bottom sections of the first ~ ;-
receptacle are preferably provided with friction reducing means,
e.g., with one or more rotary elements in the form of idler rolls
261, 261' which are shown in FIG. 7. The idler roll 261 has a
'4 ' , ,
peripheral surface 262 which extends slightly beyond the upper
side of the panel 216 of the section 214 so that the lowermost
sheet of a stack (not shown in FIG. 7) rests on the peripheral ;~
surface 262. The other idler roll or rolls 261' are optional; - ~-,. . . . . .
therefore, the roll 261' is indicated by phantom lines. A portion ~ -
of the peripheral surface 262 of the idler roll 261 also extends
beyond the inner side of the guide portion or strip 215 to
further enhance predictable descent of a stack into the empty box
below the receptacle which includes the section 214. The idler ~ ~-
rolls 261, 261' can be replaced with spherical rolling elements ~ ~
30 or with other suitable friction reducing means which contact the ~ -
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J~09Z563
underside of the lowermost sheet of a stack. If desired, each
section 214 may be provided with an entire battery (one or more
rows) of rotary friction reducing elements in the form of idler
rolls whose axes are normal to the direction of movement of the
support 214 to or from its retracted position. Thus, the number
of such rotary elements can be sufficiently large to insure that
the lowermost sheet of a stack does not contact the panels 216 of
the supports 214.
FIG. 8 illustrates modified friction reducing means in
the panel 316 of a section 314. The section 314 is provided with ; -
a plenum chamber 367 which is connected with a suitable source
(e.g., 24 or 124) of compressed air or another gaseous fluid and
can discharge compressed air against the underside of the lower-
most sheet of a stack by way of one or re openings 366b in the
panel 316. Each opening 366b preferably contains a ball check
.
valve having a seat 366, a spherical valving element 366a and a
spring 366d which biases the element 366a against the seat 366.
When the panel 316 supports a portion of a stack, the latter
depresses the element 366a against the opposition of the spring
366d so that the opening 366b admits compressed air from the
plenum chamber 367 against the underside of the lowermost sheet ~-
of the stack. This, coupled with friction reducing action of -
the rolling element 366a, insures that the section 314 can readily
slide with respect to the lowermost sheet during movement to the ~-
retracted position. As mentioned above, each panel 316 can be
provided with several openings 366b each of which may contain a
ball check valve or another suitable one-way valve. Compressed
fluid which issues from the chamber 367 via opening or openings
366b forms a cushion between the upper side of the panel 31fi and
the adjacent portion of the underside of the lowermost sheet,
-- 19 --
~. ~, ~ . . . . .
-` 109;Z~3
i.e., the stack actually floats on a cushion of air and remains
in optimum position during movement of the secti~n 314 to its ~ --
retracted position.
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