Note: Descriptions are shown in the official language in which they were submitted.
CA 02483172 2011-03-25
SELF-CENTERING TUCKER ASSEMBLY FOR A FOLDING ROLL
FIELD OF THE INVENTION
[0002] This invention generally relates to a folding machine for folding
sheets of
material, and more specifically, to a folding machine that includes a self-
centering tucker
assembly configured to interact with an adjacent gripper assembly to create an
interfolded
stack of sheets.
BACKGROUND OF THE INVENTION
[0003] Folding of sheets of material (e.g., paper, napkins, paper towels,
tissue, etc.) is
frequently performed using a pair of folding rolls that have interacting
mechanical gripper
and tucker assemblies. The gripper and tucker assemblies are uniformly spaced
around a
circumference of each respective folding roll to interact with one another so
as to interfold
the sheets of material. The tucker assemblies on one roll interact with the
gripper assemblies
of the adjacent roll, and vice versa, to alternately grip and tuck successive
sheets of material
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fed between the rolls. As the rolls rotate, the gripper assemblies carry and
release the folded
sheets of material to create a zigzagged interfolded stack of sheets.
[00041 Typically, each tucker assembly includes a rigid structure, referred to
as a
tucker, that protrudes from a slot or cavity in the outer surface of its the
folding roll, and each
gripper assembly is contained within a recess or slot in the folding roll. The
tucker
terminates in a point that extends outwardly of the outer surface of the
folding roll, and is
rigidly fixed in the slot or cavity in the folding roll to interface with a
gripper assembly on
the adjacent folding roll. As both the first and second folding rolls rotate,
the tuckers that
protrude from the outer surface of the first folding roll engage the gripper
assemblies of the
adjacent second folding roll, and vice versa. The sheets are fed between the
first and second
folding rolls, such that engagement of the tuckers and grippers of the folding
rolls functions
to fold the sheets during advancement of the sheets between the folding rolls.
However, the
protruding tucker typically rotates at a surface speed greater than the
recessed gripper
assembly in the adjacent roll, which can cause a snapped release of the tucker
that interrupts
and bounces the gripper assembly. The bounce can cause the gripper assembly to
release the
sheet of material and interrupt the output of the interfolding machine. Also,
in the event the
timing between the grippers and tuckers becomes disrupted, the interfolding
machine can
jam and the tucker can cause damage to the gripper and to the surface of the
folding roll.
[00051 There is thus a need for a tucker assembly for a folding roll of an
interfolder
that can accommodate the difference in surface speed between the points of the
tuckers and
the grippers. There is also a need for a tucker that is capable of
accommodating variations in
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the location of engagement of the tucker with the gripper, to prevent jamming
that can occur
when the timing between the rolls is disrupted.
SUMMARY OF THE INVENTION
[00061 In accordance with the present invention, there is provided a tucker
assembly
that includes a tucker element operable to pivot within a slot or cavity in
the folding roll, and
which includes a self-centering feature for providing alignment with the
gripper assembly of
the adjacent folding roll.
[00071 In accordance with one embodiment of the present invention, a tucker
assembly is mounted on a first rotating roll and configured to interact with a
gripper
assembly of an adjacent rotating roll for gripping a sheet of material in a
folding operation.
The tucker assembly includes a cavity or slot located in the outer surface of
the first rotating
roll, within which the tucker element is located. The cavity or slot generally
defines a slot
surface. The tucker element is disposed in the cavity or slot, and a lateral
passage is formed
in the tucker element. The tucker assembly further includes a spring disposed
in the slot,
which is operable to bias the tucker element in a radially outward direction
relative to the
circumference of the first roll. The tucker assembly also includes a cap that
is configured to
retain the tucker element in the cavity or slot against the bias of the
spring. A laterally
extending pin is disposed in the transverse passage of the tucker element. The
pin extends
through a roller, which is configured to pivot or roll the tucker element
along a mating roll
surface defined by the cavity or slot. The tucker element is configured to
retract against the
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bias of the spring, and the biasing force of the spring combined with the
pivotable mounting
of the tucker element functions to self-center the tucker element within the
slot.
[0008] In a preferred embodiment, the cap includes an arcuate outer face, and
an inner
surface of the cap defines a slot configured to receive the laterally
extending pin, which is
biased by the spring against the cap. The tucker element includes a base
portion opposite the
pointed outer end defined by the tucker element, and the base portion includes
a recess
within which the outer end of the spring is received. At least a portion of
the laterally
extending pin extends in a generally axially outwardly from the base portion
of the tucker
element and is received between a slot in the base portion of the tucker
element and the slot
portion in the cap. The tucker element further includes a recess within which
the roller is
received. The tucker element can further include a second transverse passage
to receive a
second laterally extending pin, in general alignment with the first transverse
passage and first
laterally extending passage within which the first pin is engaged. A least an
outer end
portion of the second pin is engaged with an adjacent tucker element. The
tucker element
may also include a second recess to receive a second roller mounted on the
second pin.
[0009] The invention also contemplates a folding machine that includes a first
folding
roll with a series of the gripper assemblies and a series of tucker assemblies
uniformly and
alternately spaced to interact with a series of gripper and tucker assemblies
of an adjacent
second folding roll. The series of alternately spaced gripper and tucker
assemblies generally
interact to grip, carry, and release sheets of material in a manner so as to
generate a folded
stack of sheets. Each of the tucker assemblies generally includes a tucker
element disposed
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in a cavity or slot in the first folding roll, and the tucker element includes
one or more
transverse passages. A spring is disposed in the cavity or slot, and engages
the tucker
element to bias the tucker element in a radially outward direction relative to
a circumference
of the first folding roll. A cap is configured to retain the tucker element in
the cavity or slot
against the bias of the spring. One or more laterally extending pins extend
into the one or
more transverse passage of the tucker element. A roller arrangement, including
one or more
rollers, is mounted on the one or more pins so as to pivot or roll the tucker
element along a
mating surface defined by the cavity or slot. The tucker element is configured
to retract
against the bias of the spring as well as to pivot about the one or more pins
in a self-centering
manner in the cavity or slot.
[00101 In accordance with another embodiment of the invention, a folding roll
assembly generally includes a roll having n outer surface, a cavity or slot
disposed along the
outer surface of the roll, and a tucker element disposed in the cavity or
slot. The folding roll
assembly includes a centering spring configured to bias the tucker element in
a lateral
direction normal to the radial outward direction of the roll, and a tucker cap
configured to
retain the tucker element in the slot. The tucker cap defines an arcuate outer
surface that
engages an arcuate inner surface defined by the roll. The tucker assembly
further includes a
pivot arrangement configured to allow pivoting movement of the tucker element
in the cavity
or slot. A bumper is mounted in the cavity or slot opposite the centering
spring, and works
in combination with the centering spring to self-center the tucker element in
the cavity or
slot.
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[0011] In accordance with a further aspect of the invention, there is provided
a method
of interacting a tucker assembly of a first rotating folding roll with a
gripper assembly
mounted on an adjacent second rotating folding roll with a sheet of material
disposed
therebetween. The method generally includes the steps of providing a tucker
element
disposed in a slot defined by a first roll adjacent to a gripper assembly
disposed in a slot
defined by an adjacent second roll; rotating the first and second rolls such
that the tucker
element of the first roll interfaces with the gripper assembly of the second
roll; biasing the
tucker element in a radially outward direction; restraining the tucker element
in the slot with
a laterally extending pin extending outwardly from the tucker element and
biased against a
cap mounted on the first roll; engaging the tucker element with the sheet of
material to move
the sheet into engagement with the gripper assembly; pivoting the tucker
element about the
laterally extending pin extending from the tucker element; and aligning the
tucker element in
a generally centered position in the slot about the pin.
[0012] In accordance with yet another aspect of the invention, there is
provided a
method of folding a sheet of material. The method generally includes the steps
of providing
a first rotating roll having a tucker assembly with a tucker element, and a
second rotating roll
having a gripper assembly with a blade and an anvil disposed to interface with
the tucker
assembly of the first rotating roll; engaging the tucker element with the
sheet of material
against the anvil of the gripper assembly; moving the blade of the gripper
assembly against
the tucker element to move the sheet of material against the anvil; pivoting
the tucker
element against the bias of a centering spring disposed in the slot against a
bumper; releasing
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the tucker element from engagement with the sheet of material; and
subsequently aligning
the tucker element in a generally centered orientation within the slot.
[0013] Other objects, features, and advantages of the invention will become
apparent
to those skilled in the art from the following detailed description and
accompanying
drawings. It should be understood, however, that the detailed description and
specific
examples, while indicating preferred embodiments of the present invention, are
given by way
of illustration and not of limitation. Many changes and modifications may be
made within
the scope of the present invention without departing from the spirit thereof,
and the invention
includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Preferred exemplary embodiments of the invention are illustrated in the
accompanying drawings in which like reference numerals represent like parts
throughout. In
the drawings:
[0015] FIG. 1 is an isometric view of an interfolding machine employing a
folding roll
incorporating a tucker assembly in accordance with the present invention.
[0016] FIG. 2 is a schematic side elevation view of the interfolding machine
as shown
in FIG. 1.
[0017] FIG. 3 is a detailed cross-sectional view of first and second folding
rolls
incorporated in the interfolding machine as shown in FIGS. 1 and 2,
illustrating a first
embodiment of a tucker assembly in accordance with the present invention.
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[0018] FIG. 4 is an exploded isometric view of the tucker assembly as shown in
FIG.
3.
[0019] FIG. 5 is a partial cross-sectional view of the tucker assembly along
line 5-5 of
FIG. 3.
[0020] FIG. 6 is a detailed side elevation view of a tucker element
incorporated in the
tucker assembly shown in FIG. 4.
[0021] FIG. 7 is a detailed bottom elevation of the tucker element shown in
FIG. 4.
[0022] FIG. 8 is a detailed end elevation view of the tucker element shown in
FIG. 4.
[0023] FIG. 9 is a an enlarged partial cross-sectional view of the tucker
assembly of a
first folding roll and the gripper assembly of an adjacent folding roll of the
interfolding
machine shown in FIG. 2, showing the tucker assembly approaching the gripper
assembly
during advancement of a sheet of material therebetween.
[0024] FIG. 10 is a view similar to FIG. 9, showing the tucker assembly
tucking the
sheet of material into the gripper assembly.
[0025] FIG. 11 is a view similar to FIGS. 9 and 10, showing, the gripper
assembly
gripping the sheet of material.
[0026] FIG. 12 is a view similar to FIGS. 9-11, showing pivoting movement of
the
tucker element of the tucker assembly to release the sheet of material.
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[0027] FIG. 13 is an enlarged detailed cross-sectional view of the tucker
element of
the tucker assembly as shown in FIG. 12.
[0028] FIG. 14 is a view similar to FIGS 9-12, showing the tucker assembly
disengaged from the gripper assembly.
[0029] FIG. 15 is an exploded isometric view of a second embodiment of a
tucker
assembly incorporated in the folding rolls of an interfolding machine as shown
in FIGS. 1
and 2.
[0030] FIG. 16 is an enlarged partial section view similar to FIG. 5, showing
the
second embodiment of the tucker assembly as illustrated in FIG. 15.
[0031] FIG. 17 is a detailed side elevation view of a tucker element
incorporated in
the tucker assembly as shown in FIGS. 15 and 16.
[0032] FIG. 18 is a detailed bottom plan view of the tucker element shown in
FIG. 17.
[0033] FIG. 19 is a detailed end elevation view of the tucker element shown in
FIG.
17.
[0034] FIG. 20 is a detailed cross-sectional view similar to FIGS. 9-12,
showing the
tucker assembly of FIG. 15 interacting with the gripper assembly of the
adjacent folding roll,
in a position in which the tucker assembly releases the sheet of material.
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[00351 FIG. 21 is a detailed cross-sectional view similar to FIG. 20, showing
the
tucker assembly of FIG. 15 in a position in which the tucker assembly is
disengaged from the
gripper assembly.
[00361 FIG. 22 is an enlarged detailed cross-sectional view of the tucker
assembly
shown in FIG. 20.
DETAILED DESCRIPTION OF THE INVENTION
1. Folding Machine
[00371 Referring to FIGS. 1 and 2, an interfolding machine 25 is operable to
convert a
web of material 30 into a stack of interfolded sheets of material shown at 32.
Interfolding
machine 25 includes folding rolls incorporating the tucker assembly of the
present invention,
and generally includes a first pull roll 35 and a second pull roll 40 that
receive the web of
material 30 along a path (illustrated by an arrow 42 in FIG. 2) from a supply
roll (not shown)
into the interfolding machine 20. The first and second pull rolls 35 and 40
define a nip
through which the web of material 30 passes, and function to unwind the web of
material 30
and feed the web of material 30 in a path (illustrated by an arrow 44 in FIG.
2) toward a nip
defined between second pull roll 40 and a bed roll 45. The web of material 30
is then
advanced by bed roll 45 toward a knife roll 50. In a manner as is known, the
knife roll 50
cuts the web of material 30 into sheets, each of which has a predetermined
length, and the
bed roll 45 carries the sheets of material along a path (illustrated by arrow
52 in FIG. 2)
toward and through a nip defined between bed roll 45 and a retard roll 55,
which rotates at a
CA 02483172 2011-03-25
slower speed of rotation than the bed roll 45. The retard roll 55 cooperates
with a nip roller
assembly 60 (FIG. 2) to form an overlap between the consecutive sheets of
material. The
retard roll 55 carries the overlapped sheets of material along a path
(illustrated by arrow 68
in FIG. 2) to a lap roll 65.
[0038] The lap roll 65 works in combination with a count roll 75 to eliminate
the
overlap between adjacent sheets of material at a predetermined sheet count, so
as to create a
separation in the stack 32 of interfolded sheets discharged from the
interfolding machine 25.
The lap roll 65 carries the overlapped sheets of sheet 30 along a path
(illustrated by arrow 78
in FIG. 2) toward a nip defined between a first assist roll 80 and an adjacent
second assist
roll 85. The first and second assist rolls 80 and 85 feed the sheets of the
material to a nip
defined between a first folding roll 90 and a second folding roll 95.
[0039] Referring to FIG. 2, the first and second folding rolls 90 and 95
generally
rotate in opposite directions (illustrated by arrows 96 and 98, respectively,
in FIG. 2) to
receive the overlapped sheets of material 30 therebetween. The periphery of
the first folding
roll 90 generally includes a series of the tucker assemblies 20 in accordance
with the
invention, and a series of gripper assemblies 100 uniformly and alternately
spaced to interact
with a series of tucker assemblies 20 and gripper assemblies 100 of the
adjacent second
folding roll 95. The series of alternately spaced tucker assemblies 20 and
gripper assemblies
100 of the first and second folding rolls 90 and 95 interact to grip, carry,
and release the
sheets of material in a desired manner so as to form the desired interfolded
relationship in the
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sheets of material and to form stack 32 of interfolded sheets. The folding
rolls 90 and 95
may be driven by a drive system 110 having a drive belt assembly 115 (FIG. I).
[0040] The stack 32 of interfolded sheets is discharged from between the first
and
second folding rolls 90 and 95 in a generally vertically-aligned fashion. The
stack 32 of
interfolded sheets may be supplied to a discharge and transfer system (not
shown), which
guides and conveys the stack 32 from the generally vertically-aligned
orientation at the
discharge of the interfolding machine 25 to a generally horizontally-aligned
movement. One
embodiment of a suitable discharge and transfer system is described in U.S.
Patent No.
6,712,746 entitled "Discharge and Transfer System for Interfolded Sheets".
2. Tucker Assembly
[0041] As illustrated in FIG. 2, each of the gripper assemblies 20 is
generally located
at a distance from the next adjacent tucker assembly 100 along a circumference
of each of
the first and second folding rolls 90 and 95. The spacing between the gripper
assemblies 100
and the tucker assemblies 20 determines the longitudinal dimension or length
between the
folds in the sheets of sheet 30 as measured in a direction of travel
(illustrated by arrows 96
and 98) of the first and second folding rolls 90 and 95.
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[00421 FIG. 3 illustrates a detailed cross-sectional view of folding rolls 90
and 95,
showing one of the series of tucker assemblies 20 in accordance with the
present invention,
and which is mounted to folding roll 95, interacting with one of the series of
gripper
assemblies 100 of folding roll 90. It is understood that the other alternating
series of gripper
assemblies 100 and tucker assemblies 20 of both the first and second folding
rolls 90 and 95
(as schematically illustrated in FIG. 2) are constructed similarly and
interact in a similar
manner. As illustrated in FIG. 3, the tucker assembly 20 generally extends in
a radial
outward direction from the outer circumference of the folding roll 95 to
engage the gripper
assembly 100 that is generally positioned in a recessed location on the
folding roll 90. As the
sheet of material 30 moves between the first and second folding rolls 90 and
95, the tucker
assembly 20 is configured to tuck the sheet 30 between a blade 116 and an
anvil 118 of the
gripper assembly 100, when the gripper assembly 100 is in an open position.
The blade 116
of the gripper assembly 100 subsequently rotates in a timed manner to grip the
tucked sheet
30 against anvil 118 as the tucker assembly 20 is moved out of engagement with
the sheet
30. In the closed position, the gripper assembly 100 carries and then releases
the sheet 30 so
as to create the folds in the sheets 30 that are formed in interfolded stack
32.
[00431 FIGS. 3-5 show one embodiment of the tucker assembly 20 in accordance
with
the present invention. In the illustrated embodiment, tucker assembly 20 has a
sectioned
tucker element 125, a first and a second tucker cap 130 and 132, respectively,
a first and a
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second roller 134 and 136, respectively, a first and a second pin 140 and 142,
respectively,
and a spring 155 disposed in a cavity or slot 160 in the folding roll 95. It
is understood that
others in the series of tucker assemblies 20 of the first and second folding
rolls 90 and 95 are
constructed in similar manner.
[0044] The spring 155 generally biases the tucker element 125 in a radially
outward
direction (illustrated by arrow 160) with respect to the outer periphery or
circumference 165
of the folding roll 95,
[0045] FIGS. 6-8 show the tucker element 125 of FIGS. 3-5 in detail. The
tucker
element 125 includes a pointed end 180, a midsection 185, and a base portion
190. The
pointed end 180 is configured to engage the gripper assembly 100 of the
adjacent folding roll
90 (FIG. 3). The base portion 190 of the tucker element 125 includes a recess
or opening
195 to receive the outer end of the spring 155. First and second transverse
pin openings or
passages 200a and 200b, respectively, extend along an axial length of the
tucker element 125
and are configured to receive the pins 140 and 142, respectively. A pair of
inner recesses
215a and 215b extend outwardly from the inner surface of the base portion 190
of the tucker
element 125, and are configured to receive the rollers 134 and 136,
respectively. The
number of recesses 215a and 215b and respective rollers 134 and 136 can vary.
An outer
recess 220 extends inwardly from the pointed end 180. Another pair of openings
225a and
225b pass through the midsection 185. The openings 225a and 225b receive
fasteners (not
shown) to hold the pins 140 and 142 in position on the tucker element 125.
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[0046] Referring back to FIGS. 4 and 5, the tucker caps 130 and 132 are
generally
disposed between adjacent tucker elements 125 (See FIG. 3) in a manner so as
to restrain the
pins 140 and 142 and the tucker element 125 against the bias of the spring
155. As
illustrated in FIG. 4, the tucker caps 130 and 132 generally include
respective outer faces
230 and 232 and respective inner faces 235 and 236. The outer faces 230 and
232 are
generally arcuate-shaped, and match an arcuate shape of an inner surface 240
defined by an
outer wall section 245 of the folding roll 95 (See FIG. 3). The inner faces
235 and 236 are
generally configured to interface with the base portion 190 of the tucker
element 125 and
with an inner surface 250 of the folding roll 95 (See FIG. 3). The inner faces
235 and 236
further include slot portions 255 and 256, respectively, which retain at least
a portion of the
pins 140 and 142, respectively, against base portion 190 of the tucker element
125.
Fasteners 258 and 260 in combination with the caps 130 and 132, respectively,
mount the
tucker element 125 to the folding roll 95 against the bias of the spring 155.
[0047] Still referring to FIGS. 4 and 5, the pins 140 and 142 are engaged
within the
openings or passages 200a and 200b, respectively, in the tucker element 125.
The pins 140
and 142 extend into aligned axial passages in rollers 134, 136, respectively,
and define inner
portions that are received within aligned passages in rollers 134, 136,
respectively, to support
the tucker 125 on the rollers 134 and 136, respectively. The pins 140 and 142
extend axially
outwardly from the tucker element 125, and are received between the slot
portions 255 and
256 of the caps 130 and 132 and outwardly facing troughs formed in the base
portion 190 of
the tucker element 125. The pins 140 and 142 and mounted rollers 134 and 136,
respectively, provide rotational location and guidance for inward and outward
movement of
CA 02483172 2011-03-25
the tucker element 125 along facing walls or surfaces 265 defining the cavity
or slot 160
(FIG. 3).
[0048] Folding roll 95 also defines a central axial passage AP which is
supplied with
pressurized air from a suitable pressurized air source, and which communicates
with radial
passages RP formed in folding roll 95 that supply pressurized air to cavity or
slot 160
inwardly of tucker element 120 and caps 130, 132. This feature functions to
expel air under
pressure around the components of tucker assembly 20.
100491 FIGS. 9-14 generally illustrate the sequence of operation of the tucker
assembly 20. In FIG. 9, the tucker assembly 20 is generally held in a radially
aligned
position in the slot 160 by the pins 140 and 142 in combination with the caps
130 and 132
(FIGS. 4 and 5) by application of an outward biasing force applied by the
spring 155. As roll
95 rotates in a clockwise direction from the position of FIG. 9 toward the
position of FIG.
10, pointed end 180 of tucker element 125 contacts sheet 30 so as to create a
fold or crease in
sheet 30. Tucker element 125 then interacts with the gripper assembly 100 of
the adjacent
roller 90 as illustrated in FIG. 10, so as to position the fold or crease in
sheet 30 against the
anvil of the gripper assembly 100 while the blade 116 of gripper assembly 100
is maintained
in the open position. During such movement of tucker assembly 20, the spring
155 forces
the tucker element 125 outwardly, and maintains tucker element 125 in a
radially aligned
position. Blade 116 of gripper assembly 100 is then moved to the closed
position as shown
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in FIG. 11, so that blade 116 engages the sheet 30 within the recess 220
defined by tucker
element 125, to clamp the fold in sheet 30 against the anvil 118. Continued
rotation of
folding rolls 90 and 95, as shown in FIG. 12, results in pivoting movement of
tucker element
125 about the pins 140 and 142 (FIGS. 4 and 5) while engaged by the gripper
assembly 100,
so that tucker element 125 is positioned at an angle relative to the radial
axis of cavity or slot
160. As the folding rolls 90 and 95 rotate, the tucker element 125 is free to
move against the
anvil 118 as dictated by the spring-loaded blade 116 of the gripper assembly
100. FIGS. 12
and 13 illustrate that, as the adjacent folding rolls 90 and 95 continue to
rotate, the tucker
element 125 pivots (illustrated by arrow 278) and retracts (illustrated by
arrow 280) upon
disengagement with gripper assembly 100. As the tucker element 125 pivots and
retracts in
this manner, the blade 116 of the gripper assembly 100 engages against the
sheet 30 and the
anvil 118, limiting bounce as the gripper assembly 100 carries the sheet 30.
Upon continued
rotation of folding rolls 90 and 95, as shown in FIG. 14, the bias of the
spring 155 and the
interaction of the base portion 190 and the pins 140 and 142 against the caps
130 and 132
functions in combination to re-center the tucker element 125 in a generally
radially aligned
position in the slot 160.
[00501 In the event timing of the rolls 90 and 95 is off or the tucker
encounters an
obstruction such that the tucker element 125 comes into contact with an outer
surface 285 of
the adjacent roll 90 or with the anvil of gripper assembly 100, the tucker
element 125 is
operable to retract against the bias of the spring 155 in a radially inward
direction (illustrated
by arrow 280 in FIG. 13) along the slot 160. Upon retracting in the slot 160,
the pins 140
and 142 are moved inwardly out of contact with the cap slot portions 255, 256.
The rollers
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134 and 136 roll inwardly along the surfaces 265 of slot 160, against the
outward biasing
force of spring 155, until the pointed end 180 of tucker element 125 is moved
out of contact
with the outer surface 285 or the anvil of gripper assembly 100. Rollers 134,
136 function to
maintain base 190 of tucker element 125 and pins 140 and 142 in a centered
position in the
slot 160. Thereafter, spring 155 functions to move tucker element 125
outwardly to seat pins
140 and 142 in engagement with cap slot portions 255, 256, respectively. As
explained
previously, spring 155 then operates to return tucker element 125 to a
radially aligned
position within cavity or slot 160. This feature enables tucker assembly to
accommodate
slight misalignment between tucker assembly 20 and gripper assembly 100, and
reduces the
potential costly and undesirable jams that may otherwise occur during
operation of the
interfolding machine 25.
[00511 FIGS. 15 and 16 show another embodiment of a tucker assembly in
accordance
with the present invention. In this embodiment, the tucker assembly is shown
at 300, and is
mounted on adjacent folding rolls 305 and 310 that have a similar construction
and operation
as folding rolls 90 and 95 as shown and described previously, including
alternately spaced
tucker assemblies 300 and gripper assemblies 312 that are constructed
similarly to gripper
assemblies 100 described above.
[00521 Tucker assembly 300 is generally mounted in a slot 314 (FIGS. 20-22) in
the
folding roll 310. It is understood that the tucker assemblies 300 of the
adjacent folding roll
305 are constructed in a similar manner. Tucker assembly 300 generally
includes a tucker
element 315 that cooperates with gripper assemblies 312 in a similar manner as
tucker
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element 125 as gripper assemblies 100 described previously, to form a crease
or fold in a
sheet of material, shown at 450. Tucker assembly 399 further includes a first
tucker cap 320
and a second tucker cap 322, a first pin 325 and a second pin 326, a first
slot spring 330 and
a second slot spring 332, a bumper 335, a first cartridge 340 and a second
cartridge 342, and
a pivot spring 345. The first cartridge 340 and the first pivot spring 330 are
positioned to
interface with the tucker cap 320, and the second cartridge 342 and the second
pivot spring
332 are positioned to interface with tucker cap 322. The tucker element 315,
the first and
second pins 325 and 326, and the first and second cartridges 340 and 342 are
installed in the
slot 314 and retained against the bias of the first and second slot springs
330 and 332 by the
tucker caps 320 and 322.
[00531 In the illustrated embodiment, tucker element 315 includes a pointed
end 355,
a midsection 360, and a base portion 365. The pointed end 355 of the tucker
element 315 is
configured to interface with the gripper assembly 312. Tucker element 315
includes a first
recess 370 that extends inwardly from pointed end 355. A first opening or
passage 375a and
a second opening or passage 375b extend axially inwardly from the opposite
ends of tucker
310, and receive inner portions of the pins 325 and 326, respectively. The
outer end portions
of pins 325, 326 extend outwardly of the ends of base portion 365. The tucker
element 315
further includes a recess 380 in one of the faces 385 of the midsection 360 to
receive the
pivot spring 345, and another recess 390 in an opposite face 395 of the
midsection 360 to
receive the bumper 335. The location of the pivot spring 345 and bumper 335
and their
respective recesses 380 and 390 can vary. The bias of the pivot spring 345
against the
bumper 335 is operable to radially align the tucker element 315 in the center
of the slot 314.
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CA 02483172 2004-09-30
The bumper 335 and the pivot spring 330 also act to minimize bounce in the
tucker element
315.
[0054] The tucker caps 320 and 322 function to retain the tucker element 315
in the
slot 314. Tucker caps 320 and 322 engage the outer ends of base portion 365,
and include
inner faces 395 and 396 and an outer faces 400 and 402, respectively. The
inner faces 395
and 396 are configured to interface with the ends of base portion 365 of the
tucker element
315 and an inner surface 405 of the roll 310. The outer faces 400 and 402 of
the cap 320 are
configured with an arcuate shape that matches an arcuate outer surface 410 of
the roll 310.
The caps 320 and 322 are secured to the roll 310 with one or more fasteners
420. The type
and number of fasteners 420 can vary.
[0055] The pins 325 and 326 are forced against the respective caps 320 and 322
by the
slot springs 330 and 332 and cartridges 340 and 342, respectively. The outer
end portions of
pins 325 and 326 protrude in an axial outward direction from the tucker
element 315 and
engage respective slot portions 424 and 426 defined by the caps 320 and 322,
respectively.
With this arrangement, the tucker element 315 pivots about a pivot axis
defined by the pins
325 and 326. The outer end portions of pins 325 and 326 occupy approximately
half the full
length of slot portions 424 and 426 defined by respective caps 320 and 322,
and a pin of an
adjacent tucker element takes up the remaining portion of the length of slot
portions 424 and
426, respectively, to pivotably mount the adjacent tucker element in the same
manner. The
length and size of the pins 325 and 326 can vary.
CA 02483172 2004-09-30
[0056] The cartridges 340 and 342 are centrally located within the slot 314.
In the
illustrated embodiment, the cartridges 340 and 342 each are generally
cylindrical structures
having respective top surfaces 428 and 429 that define respective slots 432
and 433 to
receive the pins 325 and 326, respectively. The cartridges 340 and 342 and
respective slot
springs 330 and 332 bias the tucker element 315 in a radial outward direction
with respect to
a circumference 434 of the folding roll 310. The caps 320 and 322 retain the
tucker element
315 in the slot 314 against the bias of the cartridges 340 and 342 and
respective slot springs
330 and 332.
[0057] The tucker element 315 further includes a pair of openings 435a and
435b that
extend through the midsection 360 and above the base portion 365. The openings
435a and
435b receive fasteners (not shown) to hold the pins 326 and 326 in position on
the tucker
element 315.
[0058] In operation, as the folding roll 310 rotates with an adjacent folding
roll 305,
the tucker element 315 interfaces with the gripper assembly 312 of the
adjacent roll 305. As
the tucker element 315 approaches a blade 440 and anvil 442 of the gripper
assembly 312,
the pointed end 355 of tucker element 315 engages a sheet 450, and moves the
sheet 450 into
contact with the anvil 442 of the adjacent gripper assembly 312. The contact
of the tucker
element 315 against the anvil 442 forces the tucker element 315 to pivot
slightly forward
against the bumper 335. As the folding roll 310 continues to rotate, the
tucker element 315
moves in the opposite direction against the force of pivot spring 345. The
blade 440 of the
adjacent gripper assembly 312 is moved against the anvil 442 to grip the sheet
450. As the
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folding roll 310 continues to rotate, the tucker element 315 retracts is
retracted within slot
314 against the biasing force of springs 330 and 332, which facilitates
disengagement of
tucker element 314 from anvil 442 and sheet 450. The blade 440 clamps the
sheet 450
against the anvil 442, and the pivoting and retracting movement of tucker
element 315
functions to eliminate bounce that may otherwise occur in the folding process.
The pivot
spring 345 in combination with the bumper 335 then return the tucker element
315 to a
centered position in the slot 314, and springs 330 and 332 return tucker
element 315 to its
fully extended position.
[0059] In the event the tucker element 315 contacts the outer surface of the
adjacent
folding roll 305 or anvil 442, tucker element 315 retracts within slot 314
against the outward
bias of springs 330 and 332. Tucker element 315 and attached pins 325 and 326
retract in a
radial inward direction within the slot 314. As the tucker element 315 and
attached pins 325
and 326 retract inwardly, the pins 325 and 326 are moved out of engagement
with the caps
320 and 322, and move inwardly against the bias of slot springs 330 and 332
along with
cartridges 340 and 342, respectively. The retraction of the tucker element 315
along the slot
314 prevents the tucker element 315 from damaging the adjacent roll 305 and
its associated
components, and also prevents jams which may otherwise occur, in the event the
of a
disruption in the timing of the rolls and or deviations due to manufacturing
or installation
tolerances. Following retraction of the tucker element 315, the bias of the
cartridges 340 and
342 and associated slot springs 330 and 332 along with the pivot spring 345
and bumper 335
act to return tucker element 315 to the extended position, and to self center
the tucker
element 315 in the slot 314.
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[0060] It should be understood that the present invention contemplates any
type of
arrangement that provides pivoting movement of the tucker element relative to
the folding
roll, and is not limited to a pin-type pivot arrangement. For example,
pivoting movement of
the tucker element within the slot may be accomplished without a pivot pin by
means of the
base of the tucker engaging the slot edges, with the tapered area of the base
accommodating
pivoting movement of the tucker element. It is also to be understood that the
present
invention contemplates that the tucker element is at a predetermined
orientation relative to
the folding roll when the tucker element is in the extended position. While
the
predetermined orientation may be radially aligned, it is also understood that
the
predetermined orientation may also be angled or biased either forwardly or
rearwardly within
the slot.
[0061] A wide variety of machines or systems could be constructed in
accordance
with the invention defined by the claims. Hence, although the exemplary
embodiments of a
tucker assembly 20, 300 in accordance with the invention has been generally
described with
reference to an interfolding machine 25 for folding sheets 30 into an
interfolded stack 32, the
application of the tucker assembly 20, 300 is not so limited. The tucker
assembly of the
invention could be employed to fold any type of sheet or web material such as
30, for a wide
variety of uses to machines and is not limiting on the invention.
[0062] The above discussion, examples, and embodiments illustrate our current
understanding of the invention. However, since many variations of the
invention can be
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made without departing from the spirit and scope of the invention, the
invention resides
wholly in the claims hereafter appended.
24
