U.S. patent number 3,902,710 [Application Number 05/378,599] was granted by the patent office on 1975-09-02 for accordion, folding and cutting apparatus.
This patent grant is currently assigned to Westvaco Corporation. Invention is credited to John DeLigt.
United States Patent |
3,902,710 |
DeLigt |
September 2, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Accordion, folding and cutting apparatus
Abstract
Apparatus for forming accordion folds in a longitudinally
traveling web of substantially uniform width and indefinite length
including web cutting means disposed upstream or downstream of said
folding apparatus.
Inventors: |
DeLigt; John (Covington,
VA) |
Assignee: |
Westvaco Corporation (New York,
NY)
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Family
ID: |
22644546 |
Appl.
No.: |
05/378,599 |
Filed: |
July 12, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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176487 |
Aug 31, 1973 |
3784188 |
|
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Current U.S.
Class: |
493/422;
493/423 |
Current CPC
Class: |
B65H
45/101 (20130101); B65H 45/20 (20130101); B65H
45/24 (20130101); B26D 1/02 (20130101); B65H
2701/1824 (20130101) |
Current International
Class: |
B26D
1/02 (20060101); B26D 1/01 (20060101); B65H
45/00 (20060101); B65H 45/101 (20060101); B65H
45/24 (20060101); B65H 45/20 (20060101); B65H
45/12 (20060101); B65H 045/00 () |
Field of
Search: |
;270/61F,79,30-31 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Michell; Robert W.
Assistant Examiner: Heinz; A. J.
Attorney, Agent or Firm: Marcontell; W. Allen Schmalz;
Richard L.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
The present application is a division of my earlier application
Ser. No. 176,487 filed Aug. 31, 1971 and now issued as U.S. Pat.
No. 3,784,188.
Claims
Having disclosed a specific, preferred embodiment, I claim as my
invention:
1. An apparatus for folding thin sheet material of relatively
constant width and indefinite length into a continuum of reverse
folded panel sections of uniform length comprising:
A pair of flexible tensile elements having first and second opposed
faces, respectively, each tensile element disposed in respective
closed, parallel-planar circuits around a plurality of wheel
elements having rim portions rotatable about axes positioned within
the periphery of a respective circuit and substantially
perpendicular to the plane thereof, the first face of said tensile
elements being disposed adjacent said rim portions;
Sheet material tucker means and gripper means secured to and
projecting from the second face of each tensile element in
uniformly spaced, alternate positions thereabout, each gripper
means comprising a cooperative pair of gripping elements, each
gripping element being rotatable about a pair of articulation axes
rigidly positioned relative to said gripping element, passing
through the respective tensile element and disposed substantially
perpendicular to the plane of the respective closed circuit, said
cooperative pair of gripping elements being adjacently positioned
longitudinally along said tensile element whereby projecting
portions of each gripping element are relatively drawn to a closed
position to cooperatively grip a transverse portion of sheet
material therebetween when all articulation axes respective to said
cooperative pair are disposed in a common plane;
A first of said wheel elements respective to each closed circuit
being relatively positioned to guide said tensile elements into a
meshing region of sufficient proximity for registered tucker means
on one tensile element to mesh between a cooperative pair of
gripping elements on the other tensile element that are opened by
an arcuate disposition of the articulation axes respective to said
gripping elements against the rim of the respective first wheel
element whereby a transverse portion of sheet material is tucked
between said gripping elements;
A second of said wheel elements respective to each closed circuit
being positioned relative to said first wheel element whereby a
first portion of the respective closed circuit therebetween follows
a first substantially straight line path between tangency with said
first and second wheel elements, said first straight line paths
respective to both closed circuits being aligned to relatively
diverge at a first included angle from said meshing region to
withdraw said tucker means from between said gripper elements;
A third of said wheel elements respective to each closed circuit
being positioned relative to said wheel element whereby a second
portion of the respective closed circuit follows a second
substantially straight line path between tangency with said second
and third wheel elements, said second straight line paths
respective to both closed circuits being aligned to relatively
diverge from tangency with said second wheel element at a second
included angle that is greater than said first included angle;
and
Each of said second wheel elements further comprising profile means
in the rim surface thereof that is rotatively registered to engage
all articulation axes of a cooperative pair of gripping elements
with a rim surface discontinuity, said profile means simultaneously
supporting all of said articulation axes associated with said
cooperative pair of gripping elements in a common plane that is
substantially perpendicular to the plane of the respective closed
circuit to prevent said gripping elements from opening to release
said sheet material while said gripping elements are carried by the
movement of a respective tensile element along a respective closed
circuit from said first straight line path to said second straight
line path.
2. Apparatus as described by claim 1 wherein each laterally spaced
flexible tensile element of said pair comprises a pair of tensile
members circulating about laterally spaced, parallel-planar closed
courses, said gripping elements comprise a pair of parallel
gripping bar elements spanning between respective pairs of said
tensile members, said tucker means comprising a single bar element
spanning between respective pairs of said tensile members.
3. Apparatus as described by claim 2 wherein said gripping bar
elements are drawn to the closed position by tensile forces within
respective tensile elements while in traverse along said first and
second straight line paths.
4. Apparatus as described by claim 3 wherein said tensile members
comprise a closed loop of pivot journal joined rigid link elements,
said second wheel element rim surface discontinuity comprising a
notch in said rim of sufficient depth to receive a pivot journal
between a cooperative pair of gripping bar supporting link elements
in the same plane as adjacent link pivot journals while in
traversal about the rotational axis of said second wheel element
between said first and second straight line paths.
5. Apparatus for folding a continuous web comprising:
A pair of continuous link chain assemblies, each assembly
comprising an endless loop of pivot journal joined rigid link
elements, each loop having respective inner and outer peripheries,
each assembly being disposed in a respective closed planar circuit
around at least three sprocket wheels having rim portions rotatable
about axes positioned within the periphery of a respective closed
circuit and substantially perpendicular thereto the closed circuits
respective to said pair of assemblies being substantially coplanar
aligned;
Web material tucker means and gripper means alternatively
positioned around and projecting from the outer periphery of each
chain assembly and secured to respective links therein, each said
gripper means comprising a cooperative pair of gripper elements
secured respectively to two longitudinally adjacent links that are
relatively pivotable about an axis through a common journal whereby
a web of material is gripped between said cooperative pair of
gripper elements, when all pivot axes respective to the respective
two gripper element supportive links are disposed in a common
plane;
A first pair of said sprocket wheels comprising one sprocket wheel
within each circuit being relatively positioned whereby a tucker
means secured to a link in one chain assembly will mesh between a
cooperative pair of gripper elements on the other chain assembly to
tuck a transverse crease of said web material between said gripper
elements when link journals respective to said meshing gripper
elements and tucker means are arcuately disposed against respective
first sprocket wheel rim portions;
A second pair of said sprocket wheels comprising one sprocket wheel
within each circuit, each being positioned relative to respective
first sprocket wheels whereby a portion of the respective chain
assembly circuit follows a first substantially straight line path
between tangency with said first and second sprocket wheels, said
first straight line paths respective to said pair of chain assembly
circuits being relatively diverging at a first included angle from
tangency at said first sprocket wheel to withdraw said tucker means
from between said cooperative pair of gripper elements;
A third pair of said sprocket wheels comprising one sprocket wheel
within each circuit, each being positioned relative to respective
second sprocket wheels whereby a portion of the respective chain
assembly circuit follows a second substantially straight line path
between tangency with said second and third sprocket wheels, said
second straight line paths respective to said pair of chain
assembly circuits being relatively diverging at a second included
angle from tangency with said second sprocket wheel, said second
included angle being greater than said first included angle;
and
Each of said second pair of sprocket wheels further comprising
profile means in the rim surface thereof that is rotatively
registered to engage all pivot journals respective to a cooperative
pair of gripper element supporting links with a rim surface
discontinuity, said profile means simultaneously supporting all of
said supporting link pivot axes in a common plane that is
substantially perpendicular the plane of respective chain assembly
circuits to prevent said gripper elements from opening to release
said web material while said gripper means are carried by the
movement of a respective chain assembly along a respective circuit
from said first straight line path to said second straight line
path.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of paper converting and
comprises apparatus for accordion folding and cutting of a
continuous paper web supply.
2. Description of the Prior Art
The continuous, mechanized, accordion folding of a paper web of
indefinite length has long been a valuable technique in the process
of converting large, roll quantities of paper into smaller, more
convenient units suitable for individual consumer handling. Through
the years, many devices to perform this function have evolved as
the demand for greater web speed has increased.
Among such prior art devices have been the inventions of Meisel,
U.S. Pat. No. 568,307, and Teall, U.S. Pat. No. 1,290,800. Both of
these inventions, like that of the present, utilize identical link
chain carriers on opposite sides of an oncoming web having a
multiplicity of projections secured with uniform spacing around the
periphery of each chain set which operatively cooperate to displace
the web first to one side of a center plane and then to the other,
forming a small radius crease at the position of direction
reversal. However, both of said earlier inventions require
substantial dynamic mass as related to the fold length: an
intolerable characteristic for high speed machinery.
Moreover, due to the large turning radius of such prior art
machines, similarly large clearances from the point of crease
formation to other cooperating machinery such as web cutters are
required. An undesirable incident of such large clearances is the
long, uncontrolled paper "tail" following a prefold web cut which
must be caught and drawn into the accordion fold machinery to a
point of positive control.
The present invention discloses a continuous web, accordion folding
apparatus suitable for construction with small, light weight
elements commensurate with high speed operation.
Another object of the present invention is to provide accordion
folding apparatus requiring small operational clearance to decrease
the proximity between a pre-creasing web cutter and the first point
of positive control within the folding apparatus.
Other objects of the present invention include the disclosure of a
post-creasing web cutting apparatus for severing a continuous web
in the bight of a crease after the formation of same.
SUMMARY OF THE INVENTION
The folding apparatus of the present invention comprises two
identical pairs of link-chain circuits, each pair being disposed on
opposite face sides of an oncoming web of paper or other thin sheet
material of indefinite length. Chain circuits respective to each
pair are disposed for running in parallel planes around respective
sprocket sets. Each chain in a pair has secured thereto the
respectively opposite ends of several tucker and gripper bars
extending between and across the two chains of a pair. Said tucker
and gripper bars are positioned perpendicularly to the chain
running plane and distributed alternately at uniform intervals
around the circuit periphery.
Each gripper bar comprises two, channel shaped structural members,
each having one leg thereof secured to one of two longitudinally
contiguous chain links. The bight openings of said channels are
disposed in facing opposition and filled with a soft, compliant
substance such as elastomer.
Each tucker bar comprises a structural "T" element having the
crossmember thereof secured to respective chain links and the T leg
projecting perpendicularly therefrom.
Operationally, the two chain pairs are synchronized whereby the
tucker bar on one chain pair coincides with the gripper bar nip
opening of the other chain pair. As the two, longitudinally
contiguous links retaining the gripper bar are turned over a small
diameter sprocket, the consequent angular divergence between the
gripper faces causes a nip to open therebetween. Said nip opening
receives the tucker bar leg as it rolls a projection of the web
into meshing contact with the nip opening. Separation from the
sprocket returns the two contiguous gripper bar carrier links to a
straight line geometry thereby closing the gripper faces on the web
held therebetween.
Since the straight-run sections of chain circuit departing from the
meshing sprockets are aligned for slight relative divergence, the
tucker leg is withdrawn from the gripper nip at very slight planar
misalignment. As soon, however, as the tucker leg is withdrawn from
the gripper, the chain angle of divergence is increased greatly by
turning around an idler sprocket having a chain engagement profile
such as to retain a straight line geometry between the two
contiguous gripper bar carrier links. This geometry prevents the
gripper from opening and prematurely releasing the crease.
This increased divergence angle rapidly advances the web crease to
the desired release position where at the chain circuit is directed
around another, small diameter, conventional profile, sprocket for
the purpose of opening the gripper to release the web.
If the web is to be cut following folding, a reciprocating blade
engages the web along the crease bight. Simultaneously, a set of
chain driven, cylindrical rollers are positioned against the web on
the side opposite from the blade edge for loaded rolling contact
there along to cut the web.
As an alternative embodiment of the invention, an interleaved
series of short sheets may be accordion folded into a rectangular
dispensing stack by prefold cutting the webs of two, independent
supply streams into sheet length increments, merging the two supply
streams into one, double layer stream with the transverse edges of
one stream indexed to coincide with the midpoint between sheet
edges of the other stream and orienting the double layer stream
with the present folding apparatus to grasp, within the nip of a
single gripper, two, serially adjacent, transverse sheet edges
within the linking bight of a laterally adjacent sheet crease.
BRIEF DESCRIPTION OF THE DRAWINGS
Relative to the drawings wherein like reference characters
designate like or corresponding parts throughout the several
views;
FIG. 1 is a line schematic of the accordion folding apparatus of
the present invention integrated with a post-fold cutting
apparatus;
FIG. 2 is a partial elevational view of the folding apparatus of
FIG. 1 as seen at cut II--II;
FIG. 3 is a detail of the chain carried tucker and gripper elements
of the folding apparatus;
FIG. 4 is a schematic illustrating the mechanics operative in
placing a transversely creased portion of web within the open nip
of a gripper element;
FIG. 5 is a geometric detail of the cam element for turning the
folding apparatus chain direction without prematurely opening the
grippers;
FIG. 6 is a plan detail of the rolling cutter apparatus for cutting
a web after the accordion fold is formed;
FIG. 7 is an isometric schematic showing the power transmission
train to the rolling-cutter apparatus;
FIG. 8 is a plan view of an alternative scheme for selectively
retracting the rolling cutters from the reciprocating blade table
plane;
FIG. 9 is a sectional elevation of FIG. 8 as seen across cut
IX--IX;
FIG. 10 is a second alternate to the rolling-cutter apparatus of
the invention;
FIG. 11 is an exaggerated schematic of folded product from the
apparatus illustrated in FIG. 12;
FIG. 12 is a folding apparatus of the present invention integrated
with a prefold-cutting apparatus for producing the interleaved
sheet product of FIG. 11.
FIG. 13 is a schematic of an alternative blade shape and associate
web cutting pattern available from the roller-cutter apparatus of
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
1. Operation Flow Sequence
Starting with the FIG. 1 schematic, a paper web W of indefinite
length is shown as delivered to the accordion folding apparatus at
a controlled rate by pulling rolls 20. Right and left roller chain
circuits 3a and 3b functionally cooperate in the proximal region A
to alternately engage the web W at regularly spaced distances along
the web length. The engagement forms a straight crease or pinch
line extending perpendicularly transverse to the web length axis
with the bight openings of successive creases facing in alternately
opposite directions, i.e. away from the chain supporting that
particular crease.
Each crease is carried by its respective supportive chain to the
lower, release proximity B where the web panel W.sub.4 is
substantially horizontal and will gravity drop to a flat position
without wrinkling.
Although this disclosure of the preferred embodiment describes the
endless carrier elements 3a and 3b as roller chains, it should be
appreciated that numerous alternatives, generically characterized
as endless traction means, may be equally suitable for particular
applications. Among such alternative may be included other types of
chain drives, belts, ropes or cables. Relative rotational timing
between the two circuits 3a and 3b is critical since rigid elements
structurally secured to each circuit must physically cooperate by
meshing. However, it is entirely possible to design a belt carrier
system in which the inherent slippage between the traction carriers
and the associate sheaves (sprockets) is not so great as to be
within meshing tolerance from one meshing half cycle to the next.
Coincident therewith, each incident of meshing would physically
correct any misalignment of relative index occurring within the
preceding half cycle of operation.
To cut the infinite length web W into uniform lengths terminating
precisely along a crease bight centerline, a post-fold cutting
mechanism 4 is disposed between the folding apparatus and product
receiving hopper 9. If provision for cutting web creases falling on
either side of web flow centerline C is desired, cutting mechanism
4 may comprise two blade tables 41a and 41b and two roller-cutting
units 42a and 42b. Blade table 41a and roller unit 42a functionally
cooperate as a set to sever crease lines on the right side of
centerline C whereas table 41b and roller unit 42b cooperate for
left side cuts, exclusively.
An alternative embodiment is illustrated by FIG. 12 where prefold
cutting is performed on two web sources 10 and 11 for the purpose
of interleaving one panel section of a folded sheet between
integral panels of a second, folded sheet.
2. Folding Mechanism
Each chain circuit 3a and 3b in FIG. 1 comprises a pair of roller
chains 30 encompassing sprockets 31, 32, 33 and cam 34. There being
two, parallel, chain running planes, R and L, (FIG. 2), having
rigid transverse structural ties (tucker 35 and gripper 36), in
each chain circuit 3a and 3b, a total four chain closures, L30a,
R30a, L30b and R30b, are described herein. It should be understood,
however, that the number of running planes, e.g. R and L, may be
increased for the purpose of folding wider paper. To do so, would
increase the number of chain closures by two for each running plane
added.
Both chain circuits 3a and 3b being of identical construction,
further description will be focused on circuit 3a.
Relative to FIGS. 2 and 3, it may be seen that each gripper bar 36
comprises two, longitudinal structural channel elements 61 filled
with elastomer 62. The interface between the two elastomer portions
62 is separable to form respective gripper jaws 66. The two
elements 61 of each gripper bar 36 are respectively carried by the
two, relatively articulatable, contiguous, link pairs 63o and 63i
forming link set 64. Tabs 65, integral with the links 63, may be
used as attachment platforms for the channels 61 to the links
63.
Tucker bar 35 is shown to be a unitary, extruded T or "L" element
comprising cross-bar 51 and leg projection 52. Like the gripper 36,
tucker bar 35 may be secured to link pair 53 by means of an
attachment platform 55.
The number of tuckers 35 and grippers 36 allowed on each chain
circuit is arbitrary above the permissible minimum of 2 tuckers and
2 grippers. For purposes of timing, coordination, etc., there
should be a whole number ratio between the sum of grippers and
tuckers and the length of the circuit in pitches.
The distance D between a gripper 36 and adjacent tuckers 35 on the
same chain is related to, but not the same as, a panel length S.
Therefore, the linear quantity of web W pushed by the rolls 20
between chain circuits 3a and 3b in the interim between points of
tucker-gripper engagement is greater than the distance D as
represented by the sag in FIG. 1 web sections W.sub.1 and
W.sub.2.
The opening and closing operations of grippers 36 are functions of
relative geometry as the chains are drawn over the periphery of
sprockets 31 and 32. The distance P (FIGS. 3 and 5) between chain
rollers 37 is held constant by the interconnecting rigid links 63.
Accordingly, the sprocket pitch P may be defined as a chord
subtending an .alpha. degree arc on the pitch circle M of radius of
N (FIG. 4). Gripper faces 66 are placed at a distance K (FIG. 3)
above the plane including the axes of two adjacent rollers 37 and
disposed to abut, or nearly so, between sprockets when the roller
center beneath the gripper face 66 falls into a plane common to the
centers of those rollers adjacent both sides. Since the geometry of
a link pair 63 between adjacent rollers 37 is rigid, when a gripper
bar unit 36, having cooperative jaw elements on two adjacent link
pairs 63i and 63 o of a link set 64, is drawn over the periphery of
a sprocket, the jaws 66 are separated by a mean distance
substantially equal to 2(K) (Sin .alpha.). As the chain departs
from contact with a sprocket, the roller centers return to the
straight line relationship thereby closing the jaws 66.
Rotational timing of the chain circuits 3a and 3b is as shown by
FIGS. 1 and 4 whereby the tucker leg 52 of one chain circuit rolls
between the opened jaws 66 of gripper 36 on the opposite chain
circuit. Since the meshing of cooperative tuckers and grippers is
from opposite sides of the web W, a portion thereof is pressed
between the open gripper jaws 66 as shown in FIG. 4. As the chain
rolls off the sprocket 31b, jaws 66 are pulled together to close on
tucker leg 52, clamping the web W therebetween.
In order to withdraw the tucker leg 52 from the nip of jaws 66
without disrupting or damaging the web therebetween, the chains
course half angle of departure .alpha. from sprockets 31a and 31b
must be held to shallow maximums. The exact angle may be
analytically derived by those of ordinary skill in the art but for
purposes of example, half angle .alpha. may be in the order of
5.degree..
At this point in the operation, gripper 36 has established a crease
in the web and leg 52 of tucker 35 has been withdrawn therefrom.
Moreover, the crease held by chain circuit 3b is slightly to the
left (FIG. 1) of center plane C. The next succeeding crease will be
held by chain circuit 3a and will be drawn to the right of center
plane C thereby establishing an accordion geometry bias. However,
no reliably repetitive fall pattern may be acquired or positive
control exercised if the web is released. Wrinkles and irregular
stacking patterns will result if the web is released from the
positions W.sub.2 or W.sub.1. Therefore, the generally vertical
disposition of the accordion must be reoriented to a generally
horizontal disposition as represented by web sections W.sub.3 and
W.sub.4. To accomplish this result, the creased end of web section
W.sub.3 held by chain circuit 3b must be advanced laterally (to the
left) from the center plane C at a greater rate than the circuit 3a
held crease of the same section W.sub.3. Simultaneously, the
vertical displacement between the two ends of section W.sub.3 must
be reduced.
An obvious technique of such reorientation is to increase the rate
of circuit divergence by the half angle quantity of .beta. ,
25.degree. for example, as by bending around an intermediate cam
34. But if the idler includes a conventional profile, gripper jaws
66 will open and release the web prematurely as the gripper bar 36
passes thereover.
To avoid this result, cam 34 of the present invention are provided
with notches 38 which are rotationally timed to receive the center
roller of the three roller groups supporting a gripper bar link set
64. As represented by FIG. 5 the centers of the three link set 64
supportive rollers 37 are allowed to sustain a straight line
relationship at the point of chain tangency to the idler 34. The
depth and profile of the notch 38 may be determined analytically by
those of ordinary skill in the art from chain pitch P, chain roller
radius r, the initial departure angle .alpha. and the final
departure angle .beta. . Since link pairs 63i and 63o are precluded
from relative angular displacement as the set 64 turns about idler
34, jaws 66 are held tightly closed on the crease of web W.
The next critical design point of the present invention is the
vertical placement of release sprocket 32 below idler 34. The
controlling criterion is the length of a moderately tensioned web
section W.sub.3 so that gripper bar 36 on chain circuit 3b will
open as the gripper 36 on chain circuit 3a moves into position to
pull the 3b circuit crease from between jaws 66.
If only continuous and rapid accordion folding of web W is desired,
the aforedescribed apparatus will flawlessly deliver a rectangular
column continuum of accordion folded web to a receiving station
such as chute or hopper 9.
However, if finite lengths of folded web, in whole number
increments of web sections between creases, are desired, the
aforedescribed folding apparatus may have integrated therewith the
post-fold cutting mechanism 4.
3. Post-Fold Cutting Mechanism
The preferred embodiment of the post-fold cutter comprises two
blade tables 41a and 41b disposed in the same plane below release
sprockets 32.
The two tables 41a and 41b function alternately with one, 41a of
FIG. 1, penetrating the material flow column between web sections
W.sub.4 and W.sub.5 from the left of center plane C and the other,
41b, penetrating between web sections W.sub.3 and W.sub.4 from the
right of center plane C.
Both tables 41a and 41b are provided with knife edges 43a and 43b
for positionment within the bight of a crease.
Rotating into position against the knife edges 43a and 43b but from
opposite sides of the web W.sub.1 are respective roller mechanisms
42a and 42b. As best illustrated by FIG. 6 relatively wide, flat
tread wheels 44 cut the web W by pressing same against the knife
edge 32a with rolling contact. Resiliently loaded backing bar 45
maintains a relatively constant contact pressure between wheels 44
and the web W to assure complete cutting across the full web width
as the edge and tread surfaces wear. The treads of wheels 44 should
be "flat," i.e. relatively long surface elements of a regular
cylinder, to provide broad accommodation for the degree of
functional misalignment as eventually, if not initially, occurs in
high speed, cyclically reversing machinery.
Rollers 44 are mounted on carrier links 47 of a sprocket driven
roller chain 46. Spacing between rollers 44 along the chain 46 may
be as desired, one factor of consideration being the length of
allowable cutting interim within an operational cycle: a smaller
separation distance between rollers yields a shorter cutting time
for a given chain speed.
It should be appreciated that a cutting operation performed by the
aforedescribed apparatus of this invention is not only rapid due to
simultaneous cutting of several small increments across the web
width but is also neat, there being no opportunity for shredding
due to blade misalignment. The present invention allows only one
cut line, that allowed by the continuous line of knife edge 43a or
43b, regardless of the variance the edge line may follow from true
(within the limits of the wheel 44 tread width). Therefore, a
single, continuous cut line may be achieved with the rapidity of
multiple cutters.
Although any number of mechanisms may be devised for selectively
engaging the knife edges 43 with rollers 44, the schematic shown in
isometric by FIG. 7 is of a particularly successful example. Knife
tables 41a and 41b are mounted on guide bars 70 and reciprocably
driven by four-bar crank mechanisms 71a and 71b. Since the web
cutting operation is cyclical over an interrupted period, greatest
flexibility for programing the cycle period is afforded by linking
the input power line shaft 72 with the lateral, power transfer
shafts 75a and 75b carrying lateral spur gears 73a and 73b through
electrically latched, single revolution clutches 74a and 74b such
as a Type 6 as specified by the Hilliard Corporation of Elmira, New
York.
Condition sensory means such as a limit switch or photo sensory
switch, not shown, for actuating either of clutches 73a or 73b by
the emission of a suitable electrical signal, may be responsive to
select portions of the folding mechanism or drive therefor such as
the notched cam 34.
With each operational cycle of the blade tables 41a and 41b, so
too, are positioned roller-cutter units 42a and 42b by means of
carriage 48, parallel swing arms 49 and eccentric 77 driven
connecting rod 76.
With clutch 74a engaged, for example, power is transferred from
shaft 72 to shaft 75a via spur gear 73a. Shaft 75a transfers power
to the four-bar linkage 71a via chain transmission 78a (thereby
sliding blade table 41a between web panels W.sub.4 and W.sub.5
(FIG. 1)). Simultaneously, chain transmission 79a draws power from
shaft 75 a to rotate eccentric 77a for raising the roller-cutter
unit 42a into operative engagement with knife edge 43a mounted on
blade table 41a.
Roller chain 46 carrying cutting wheels 44 is driven continuously
by direct power take-off 80a from main input power shaft 72 thereby
further minimizing the cutting delay time.
As of the aforedescribed point of operation, the cutting cycle for
the crease joined web panels W.sub.4 and W.sub.5 is only half
complete although the web is completely severed. However, since the
ratio between the power shaft 72 gear is 2:1 for a complete cycle,
the one revolution clutch 74a must be actuated a second time to
withdraw blade table 41a from the web flow column. This second
actuation may be keyed to such an event as the completion of a dump
cycle for hopper 9 to remove the material collected therein and
severed from the web W by the rolling-cutter apparatus.
After the cutting plane between guide bars 70 has been cleared by
the retraction of roller-cutter 42a and blade table 41a therefrom,
the circuit for actuating cutting apparatus 41b and 42b is prepared
for completion by a second panel counting circuit. In this manner,
web creases on sequentially opposite sides of the material flow
axis C are cut with a predetermined number of integrally connected
panels therebetween.
It should be understood that the scale and disposition of elements
in FIG. 7 is distorted to further the ends of clarity and
disclosure. Although the gear and sprocket ratios of the FIG. 7
mechanism are critical, they are so for a very limited product
range. These are matters within the competence of ordinarily
skilled practitioners of the art and need no further
elaboration.
It should be noted, however, that depending on associated machine
geometry and the nature of power available, the rolling-cutter
mechanisms disclosed by FIGS. 8, 9 and 10 may be more suitable.
The FIGS. 8 and 9 embodiment, for example provides an alternative
to physically displacing a driven sprocket under load as required
the FIG. 7 mechanism. In FIGS. 8 and 9 the rolling contact surfaces
are frustums of regular cones 81 carried on an expansible chain
circuit 82 loaded tensionally by reciprocable load shoes 83a and
83b. Linking piston rods 84 fitted through cylinder block 85
rigidly unitize shoes 83a and 83b whereby fluid pressure
resiliently biased against an annular collar piston surface (not
shown) within the cylinder block 85 engages the rolling contact
surface 81 with the knife edge 43a. When the cut is complete, fluid
pressure bias on the piston collar is reversed to retract all
chains and roller elements from the blade table reciprocation
plane.
The rolling cutter mechanism of FIG. 10 is highly simplified and
represents the basic elements of an application where the most
convenient power application is a single or double stroke linear
displacement of a machine element from point Y to point Z. The
elements of FIG. 10 include the arcuate segment of a cylinder
having a radius E. The cylindrical surface 86 is rolled into
contact with the knife edge 43a by driving a rod or roller element
87 along arcuate slot 88 from point Y to point Z. As surface 86
rolls about the axis F, the axis position translates to point
F'.
FIG. 13 further illustrates the design flexibility available to the
present invention by allowing complex cutting patterns such as the
undulating or scalloped edge of panel W.sub.5 ' without sacrifice
of cutting speed or precision. Since the thread width of rollers 37
exceeds the amplitude of knife edge 43c undulations, the cut line
for web W.sub.5 ' will follow exactly that of the knife edge
notwithstanding the fact that several rollers 37, rapidly
traversing short increments of the web width, serve as separate
anvils over respective increments.
Many variations of the scalloped edge scheme of FIG. 13 may be
comprehended within the teaching of the invention, such as Greek
scroll or sawtooth, the primary criterion being that the web W is
pressed against all transverse elements of the edge 43c by loaded,
rolling, contact pressure.
4. Prefold Cutting Mechanism
Due to the relatively short radial clearance required by the sweep
of tucker 35 and gripper 36 devices of the present invention, it is
also possible to integrate the present accordion folding apparatus
with prefold cutting apparatus to deliver a continuum of
interleaved, single folded sheets as schematically represented by
FIG. 11. Distinctive characteristics of the FIG. 11 product include
sheets 23, folded so as to open to the left of the center line, and
sheets 24, folded so as to open to the right of the center line.
The upper panels 23u of sheets 23 are disposed to overlie the lower
panels 24L of sheets 24. Conversely, panels 24u overlie panels 23L.
An integral pair of panels, 23a and 23L for example, are joined by
the bight of a crease 23b.
Relating now to the FIG. 12 apparatus for producing the product of
FIG. 11, there are shown two web supply streams 13 and 14 pulled
from reels 10 and 11 by pulling rolls 15 and 16. Rotary knives 17
and 18 cut the respective webs into a continuum of sheets 23 and
24, respectively.
Subsequent to cutting, the two supply streams are merged into a
single plane of supply 21 by the converging nip 22 between belt
conveyors 25 and 26. Rotation of the knife 17 is timed for
180.degree. angular phase displacement from the rotation of knife
18 so that upon emergence from the nip 22, the transversely cut
edges of serially adjacent sheets 23 from supply stream 13 align
with the approximate midpoint between transverse edges of laterally
adjacent sheets 24. From the nip 22, the single supply stream 21 is
delivered to the pickup area A between sprockets 31a and 31b where
the junction between serially adjacent edges of sheets 23 and the
midpoint of sheets 24 is pressed into the nip of grippers 36.
As the foregoing cycle is reversed and repeated, panels from
respective webs are interleaved in the manner represented by FIG.
11.
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