Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Attorney's Case No. 505
Tw0 ROLL WEE CUTTER AIdD 1NIET~iOD
Field of the Invention
The invention relates to two roll web cutters and methods for
cutting segments from the lead end of a moving continuous web.
Description of the Prior Art
Continuous webs of fabric, paper and the like are conven-
tionally severed by feeding the web through rotary cutting devices
having a pair of continuously rotating rolls. One roll carries one
or more knives and the second roll carries one or more anvils
engagable with the knives. The continuous web is fed toward the
rolls on a conveyor, passes between the rolls and is cut into a
number of segments. The segments are conveyed away fram the rolls
on a second conveyor.
Two-roll web cutters are used for severing webs fed at very
high speeds. i~hile cutters of this type may be satisfactory for
severing dry webs,'problems are encountered in severing wet webs.
This is because the web is sandwiched between the rolls during
cutting and the moisture in the web adheres the lead end of the
web, lacated immediately upstream from the severed end of the web,
onto one of the rolls. Adhesion of the lead end of the web on
either roll prevents the end from being fed properly downstream to
1
~~~~e~vJ~~
the takeaway conveyor and causes jams requiring shutting down of
the web cutter and associated machinery for delivering the web to
the cutter and for taking away the severed web segments.
Summary of the Invention
The invention is a two-roll web cutter and method for severing
a continuous web which is likely to adhere to one of the rolls.
Typically, the web is wet and sticks to the anvil roll as the web
is waved between the rolls and is compressed against the anvil
during cutting. Sticking is prevented by lifting up a plate
located behind or upstream of the anvil to lift the lead end of the
web off the anvil and assure feeding of the web onto a takeaway
conveyor. Sticking of the web to the knife roll is preventing by
providing circumferential grooves on the roll.
The web cutter may be used to sever segments from a continuous
web of non-woven fabric formed of synthetic fibers saturated by a
liquid. This type of web may have a number of plies and, for
instance, may be made up of a plurality of stacked Z-folded plies
which, after severing, form individual wet wipes. The web cutter
may be operated without sticking to sever a saturated web into as
many as s00 segments per minute with the segments varying from 5
1/2 to 8 1/2 inches in length and with the web being made up of
from three or more three-layer Z-fold fabric plies. The severed
segments of saturated fabric are positively fed to the takeaway
conveyor for takeaway from the cutter.
Tn a first embodiment of the invention the lift plate is
movably mounted to the anvil roll and springs bias the plate to the
2
elevated lift position. The plate is compressed immediately before
cutting. After cutting, the springs lift the plate and raise the
lead end of the web for transfer to the takeaway conveyor.
In a second embodiment of the invention, the raising and
lowering of the plate is controlled by a fixed cam and follower
connection.
Other objects and features of the invention will become
apparent as the description proceeds, especially when taken in
conjunction with the accompanying drawings illustrating the
invention, of which there are three sheets and two embodiments.
Description of the Drawinqs_
Figure 1 is a vertical sectional view, partially broken away,
of a first embodiment of the invention as the web is cut;
Figure 2 is a sectional view, like Figure 1 immediately after
cutting of the web;
Figure 3 is top view, partially broken away showing the infeed
and takeaway conveyors and the stripping plate assemblyo
Figure 4 is a sectional view of the second embodiment of the
cutting apparatus; and
Figure 5 illustrates the surface of the knife roll.
Description of the Preferred Embodiment
Web cutter 10 includes a knife roll 12 and an anvil roll 14.
A continuous web 16 is severed into segments 18 by the cutter.
Tnfeed conveyor 20 moves the web 16 to the rolls and discharge
conveyor 22 removes the severed web segments from the rolls. An
infeed guideplate 24 supports the movement of the web .into the nip
3
between the rolls and discharge guideplate 26 supports movement of
the severed segments 18 away from the roll.
Cutter 10 includes a conventional frame for rotatably
supporting the two rolls, appropriate drives fox rotating the rolls
in the directions of arrows 28 and 30 at the same rotary speed and
at a sufficiently high speed to sever segments 18 from the web at
a desired production rate. The feeds of conveyors 20 and 22 are
appropriately set up to feed the web 16 to the rollers for severing
at an appropriate rate and to remove the severed segments 18 at an
appropriate rate. The frame and drives are conventional and are
not illustrated.
Knife roll 12 includes three 120 degree spaced cutting knives
each extending along the width of the roll. The knives are
conventionally mounted on the roll. Roll 12 includes circumferen-
tial surfaces 34 extending between the three recesses use to mount
knives 32. As shown in Figure 5, these surfaces are provided with
a plurality of V-shaped circumferential grooves 36 each having a
width at surface 34 greater than the width of the narrow circum-
ferential lands 38 located between adjacent grooves. The grooves
and narrow lands assure that the saturated web and cut segments do
not adhere to the surface of the knife roll.
The anvil roll 14 includes three 120 degree spaced anvils 40
each extending along the width of the roll. The drive for cutter
10 rotates rolls 12 and 14 at the same speed and in proper synchro-
nization so that each blade 32 is rotated past an anvil 40 so that
the cutting edge of the blade very nearly engages the anvil and is
4
forced through and severs the web as shown in figure 1. The anvils
40 are secured to anvil roll 14 by convewtional mounting
connections.
The anvil roll also includes a lift plate 42 located
immediately upstream of each anvil. Plates 42 are shown in Figures
1, 2 and 3. The plates 42 extend across and are slightly wider
than the width of web 16. The ends of the plates are connected to
the upstream ends 44 of a pair of pivot arms 46. The arms 46 are
pivotedly mounted to pins 47 carried by roll 14. 'Che downstream
ends 48 of the arms carry adjustable stops 50 engagable with fixed
stops 52 carried by the anvil roll. A spring 54 is confined
between a portion of the anvil roll and the upstream end of each
arm to bias lift plates 42 to the elevated position determined by
engagement between stops 50 and 52 as shown in Figure 1. When the
plate is pressed inwardly to the depressed position and springs 54
are compressed, the downstream edge 56 of the plate is located
adjacent and slightly above an anvil 40. When the lift plate is
fully elevated by springs 54 the downstream edge 56 is moved to a
position above and over the cutting or reaction surface of anvil
40, as illustrated by the position of the lift plates 42 located
away from the knife roll 12 in Figure 1.
A plurality of grooves 58 extend across the upper surface of
each plate 42. These grooves are aligned with support fingers 60
extending downstream from the guideplate 24 and support fingers 62
extending upstream from the guideplate 26. Tree fingers 60, 62 are
5
narrower than grooves 58 to prevent engagement between the fingers
and the plate when the plate is elevated as shown in Figure 2.
The operation of web cutter 10 will now be described.
Rolls 12 and 14 axe rotated at a synchronous rate in the
directions of arrows 28 and 30 and conveyors 20 and 22 are actuated
to feed the web 16 through the nip 64 between the rolls and move
the severed segments 18 away from the nip. Each associated blade
32 and anvil 40 is rotated into the nip between the rolls. The web
16 extends between the anvil and blade. As the two rolls rotate to
the cutting position of Figure 1 the anvil and fully raised lift
plate 42 move toward the nip 64. The anvil and blade move into the
nip to sever the web as shown in Figure 1 and the lead or down-
stream edge 56 of the lift plate engages the lower surface of the
web and holds the web against the adjacent edge of roll 12. The
web is sandwiched between the roll and the plate and depresses the
plate, compresses springs 54 and lowers the plate into flat or
recess 66 formed in roll 14 as shown in Figure 1. Lowering of the
lift plate moves the lead edge 56 to a position immediately
adjacent the side of the anvil so that the web and plate are free
of blade 32 as it rotates into near engagement with the anvil and
severs the web. See Figure 1.
Figure 2 illustrates the position of the rolls shortly after
severing where the cut 68 formed in Figure 1 has moved downstream
arid is positioned on fingers 62 of the discharge guideplate 26.
During rotation of the rolls from the position of Figure 1 to the
position of Figure 2, the plate 42 is elevated upwardly by springs
6
54 to hold the overlying web against the side of the knife roll ~.2.
In this way, the lead end of web 16 at cut 68 is positively
elevated above the surface of the anvil roll 14 and fed downstream
onto the discharge conveyor 22. The ends of fingers 62 fit in the
grooves 58 in plate 42 during movement of the lead end of the
web,thereby assuring that the lead end of the web which forms the
neact successive segment to be severed from the web is properly fed
into the discharge conveyor 22. The discharge conveyor 22 includes
upper and lower belts 23 and 25 to assure engagement with and
downstream movement of segments 18. Continued rotation of the two
rolls moves the plate out of engagement with the web and knife roll
thereby allowing springs 54 to return the plate to the fully
elevated position as shown on the left hand side of Figure 1.
Web 16 may include a number of plies of a non woven synthetic
plastic folded sheet material saturated with a sticky liquid. The
wet, sticky web easily adheres to the anvil and knife rollers.
During cutting the knife presses the web tightly against the flat
cutting surface of the anvil forming an adhesion joint between the
anvil and the web. The lift plate 42 moves the leading edge of the
web upstream of the cut 68 away from the anvil to break the connec-
tion and, with fingers 62 fitted in groove 68, assures that the
leading end of the web is moved onto plate 26 and to the discharge
conveyor 22. The V-shaped grooves 36 formed in surfaces 34 on the
knife roll prevent the 'top of the web from sticking to the knife
roll despite the fact that the web is held against the roll by
plate 42 during a short interval after cutting. The nary~w lands
38 are not sufficiently wide to form large area wet connections
with the web.
The ready adhesion of the wet, sticky web to the rolls is a
significant problem at high production rates where the web may be
traveling at a rate of more than 400 feet per minute and the cutter
may be severing as many as 600 segments from the web per minute.
The stripping plates and grooves in the knife roller assures proper
feeding of the wet, sticky web at these high production rates.
Figure 4 illustrates the sectional view taken through one end
of an anvil roll 80 of a second embodiment of the invention. Roll
80 is like roll 14 but includes a cam drive for controlling the
elevation and retraction of the lift plates. The roll 80 may
replace roll 14 in a web cutter to sever lead segments 18 from web
16 as described in connection with the operation of the first
embodiment. Only anvil roll 80 is shown in Figure 4.
Roll 80 includes a body 82 essentially identical to body 84 of
roll 14. Three anvils 86, like anvils 40, are equally spaced
around the circumference of the body 82. Roll 80 also includes
three lift plates 88, like plates 42, located on the upstream sides
of the anvils 86. Each plate 88 is connected to the body by a pair
of pivot arms 90 similar to arms 46 which rotate on pins 92 mounted
on body 82. Unlike arms 46, arms 90 do not include downstream ends
or adjustable stops. Springs 94, like springs 54, are confined
between the body and the ends of the arms 90 adjacent lift plates
88 to bias the arms and lift plates toward elevated positions.
8
Fixed cam plate 96 is secured to the frame of the web cutter
by an appropriate connection (not illustrated) and includes a
central aperture 98 surrounding reduced diameter shaft 100 on the
end of the body. The shaft extends are journalled in a bearing on
5 the cutter frame. The springs 94 bias the arms 90 radially
outwardly to hold cam follower rollers 102 on the arms against the
surface of aperture 98. Aperture 98 defines a cam surface having
a sharp rise surface 104, a gradual fall surface 106 and dwell
surface 108. Rotation of roll 80 moves each roller 102 around the
10 cam surface to elevate and retract the corresponding lift plate 88
through a cycle like the cycle of plates 42 in cutter 10. The
movement of plates 88 between the retracted and elevated positions
is preferably controlled by a single cam plate engaging rollers on
arms 90 at one end of the anvil roll.
As the plate 88 is rotated up toward the nip of the web
nutter, the roller 102 is moved along the dwell surface 108 and the
plate 88 is held in the retracted position as illustrated.
Immediately before the adjacent anvil 86 is moved into the nip at
the 12:00 position, the roller 102 is moved from the dwell surface
onto the rapid rise surface 104 and springs 94 begin to move 'the
lift plate 88 to the elevated position to move the severed lead end
of the web upwardly, move 'the grooves 110 on the plate around the
fingers 62 of the discharge guideplate and assure that the new
severed lead end of the web is fed along the guideplate and into
the discharge conveyor. Initial upward movement of plate 88 occurs
immediately prior to severing the web in order to assure that the
9
2~~~~~~
plate is moved upward in time for proper feeding of the web without
interfering with cutting the web. After the lead end of the web
has been fed onto the discharge guideplate roller 102 is moved to
the fall surface 106 and the plate is returned to the retracted
position as illustrated.
While we have illustrated and described a preferred embodi-
ment of our invention, it is understood that this is capable of
modification, and we therefore do not wash to be limited to the
precise details set forth, but desire to avail ourselves of such
changes and alterations as fall within the purview of the following
claims.
