U.S. patent number 3,847,046 [Application Number 05/410,159] was granted by the patent office on 1974-11-12 for device for cutting continuous webs.
Invention is credited to Alfred Schmermund.
United States Patent |
3,847,046 |
Schmermund |
November 12, 1974 |
DEVICE FOR CUTTING CONTINUOUS WEBS
Abstract
A device for cutting continuous webs into lengths is disclosed.
The device comprises two web feed paths each having a portion
common to the other and respective cutter means associated with
each feed path. Each feed path is provided with respective web
feeder means selectively operable to feed a web past the respective
cutter means in co-ordination with the displacement of a
displaceable knife element thereof. The device is provided with web
change-over means selectably actuatable to render inoperative
simultaneously said feeder means and the cutter means associated
with one feed path and to render operative simultaneously said
feeder means and the cutter means associated with the respective
other feed path. The change-over means is actuatable only when the
knife elements of the respective cutter means are in mutually
corresponding positions, whereby the web change-over takes place
when the leading edges of respective webs are each so located at
corresponding positions in the respective feed paths that -- on the
change-over means being actuated -- the first length severed from
the respective other web is displaced along the common feed path
portion in substantially the same time interval as a length severed
from the one web would have been had the change-over means not been
actuated.
Inventors: |
Schmermund; Alfred (5820
Gevelsberg, DT) |
Family
ID: |
10454643 |
Appl.
No.: |
05/410,159 |
Filed: |
October 26, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Oct 31, 1972 [GB] |
|
|
50095/72 |
|
Current U.S.
Class: |
83/152; 83/354;
83/549; 83/303; 83/355; 83/573 |
Current CPC
Class: |
B65H
5/26 (20130101); B65H 23/24 (20130101); B65H
35/08 (20130101); Y10T 83/2185 (20150401); Y10T
83/4705 (20150401); Y10T 83/492 (20150401); Y10T
83/494 (20150401); Y10T 83/8727 (20150401); Y10T
83/8762 (20150401) |
Current International
Class: |
B65H
23/04 (20060101); B65H 23/24 (20060101); B65H
35/08 (20060101); B65H 35/04 (20060101); B65H
5/26 (20060101); B26d 007/06 (); B26d 005/20 () |
Field of
Search: |
;83/303,152,285,298,354,355,549,571,573,650 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Abercrombie; Willie G.
Attorney, Agent or Firm: Sughrue, Rothwell, Mion, Zinn &
Macpeak
Claims
I claim:
1. A device for cutting continuous webs into lengths comprising, in
combination:
guide means defining two web feed paths each having a portion
common to the other;
respective cutter means associated with each said feed path and
each having a displaceable knife element;
respective web feeder means each selectively operable to feed a web
past the respective one of said cutter means in co-ordination with
the displacement of said knife element thereof;
web change-over means selectably actuatable to render inoperative
substantially simultaneously said feeder means and said cutter
means associated with one said feed path and to render operative
substantially simultaneously said feeder means and said cutter
means associated with the respective other said feed path; and
constraining means co-operating with said change-over means and
with said knife elements to render said change-over means
actuatable when and only when said displaceable knife elements of
said respective cutter means are in predetermined and mutually
corresponding positions; whereby the web change-over takes place
when the leading edges of said respective webs are each located at
corresponding positions in the respective ones of said feed
paths.
2. A device as defined in claim 1, comprising respective further
feeder means associated with each said feed path to feed lengths of
said web severed by said cutter means along a feed path portion
extending downstream of said cutter means.
3. A device as defined in claim 2, wherein each said further feeder
means feeds said severed lengths along the respective said feed
path at substantially the same speed as that at which said
selectively operable feeder means feeds a web past said cutter
means, whereby successive said severed lengths are fed from the
respective said cutter means with substantially no gap
therebetween.
4. A device as defined in claim 2, wherein each said further feeder
means feeds said severed lengths along the respective said feed
path at a substantially higher speed than that at which said
selectively operable feeder means feeds said web past the
respective said cutter means, whereby successive said severed
lengths are fed from the respective said cutter means with a
substantial gap therebetween.
5. A device as defined in claim 2, wherein each said further feeder
means comprises a drivable endless belt downstream of the
respective said cutter means to facilitate the transfer of said
severed lengths of web along the respective one of said feed
paths.
6. A device as defined in claim 5, wherein each said endless belt
is permeable to air, and each passes around respective suction
chambers provided with a plurality of apertures through which
suction is applied to one surface of the respective said belt to
cause said severed lengths of web to adhere to the respective other
surface of said belt.
7. A device as defined in claim 1, comprising a pair of suction
roller devices disposed at a junction between said two feed paths,
each said roller device comprising a stationary inner portion and
an annular outer portion rotatable about said inner portion, said
outer portion having radially extending passages therethrough and
said inner portion defining a suction chamber of limited peripheral
extent, by means of which suction is applied to the radially inner
ends of said passages in said outer portion as such passages pass
said suction chamber, to cause said severed lengths of web to
adhere to said outer portion.
8. A device as defined in claim 7, wherein said two outer portions
define a nip between which said severed lengths of web pass to said
common feed path portion.
9. A device as defined in claim 1, wherein each said cutter means
comprises a rotary cutter, said displaceable knife element thereof
being rotatable relatively to a stationary knife element to bring
said displaceable and stationary knife elements into mutually
co-operative action.
10. A device as defined in claim 9, wherein said displaceable knife
elements are so mounted and driven, only a selected one of said
elements being driven at any given time, that said selected knife
element rotates continuously at uniform speed.
11. A device as defined in claim 9, wherein said displaceable knife
elements are so mounted and driven, only a selected one of said
elements being driven at any given time, that said selected knife
element executes individual single rotations spaced by periods of
rest.
12. A device as defined in claim 1, wherein said web change-over
means comprises a drive shaft rotatable mounted in a support, an
elongate central sleeve member mounted on said shaft to rotate
therewith and restrained from axial displacement there along, a
first sleeve member rotatably mounted on said shaft, disposed on a
shaft portion projecting from one end of said central sleeve and
axially slidable along said shaft to be selectably coupled to one
of said central sleeve and said support, a second sleeve member
rotatably mounted on said shaft, disposed on a shaft portion
projecting from the respective opposite end of said central sleeve
and axially slidable along said shaft to be selectably coupled to
one of said support and said central sleeve, first gear means
coupling said first sleeve member to said displaceable knife
element of said one cutter means, second gear means coupling said
second sleeve member to said displaceable knife element of the
respective other said cutter means, and displacement means to
simultaneously axially displace said first and second sleeves to
render inoperative one of said cutter means and to render operative
the respective other said cutter means, and vice-versa.
13. A device as defined in claim 12, wherein said support comprises
a first fixed sleeve member mounted on said shaft next adjacent
said first slidable sleeve member, and a second fixed sleeve member
mounted on said shaft next adjacent said second slidable sleeve
member, and wherein mutually co-operable dog clutch means are
provided on next adjacent end portions of said first fixed support
sleeve and said first slidable sleeve, on next adjacent end
portions of said first slidable sleeve and said elongate central
sleeve, on next adjacent end portions of said elongate central
sleeve and said second slidable sleeve, and on next adjacent end
portions of said second slidable sleeve and said second fixed
support sleeve.
14. A device as defined in claim 13, wherein each of said mutually
co-operable dog clutch means are mutually engageable only on the
respective one of said slidable sleeve members being located in a
predetermined angular position on said drive shaft.
15. A device as defined in claim 12, wherein the web change-over
means comprises electrical switch means selectably operable to
render inoperative said web feeder means co-ordinated with said
cutter means of said one feed path and substantially simultaneously
to render operative said feeder means co-ordinated with said cutter
means of said respective other web feed path, and vice-versa.
16. A device as defined in claim 15, wherein actuator means of said
electrical switch means is mechanically coupled to said
displacement means.
Description
BACKGROUND OF THE INVENTION
This invention relates to a device for cutting continuous webs.
In cigarette packaging machines a continuous web of wrapping
material intended to form for example the inner or outer one of two
wrappers applied successively to a cigarette block is withdrawn
from a supply reel or bobbin, cut into appropriate lengths, and
then fed to the part of the packaging machine which folds the cut
lengths around the cigarette blocks.
A packaging machine in which such an arrangement may be used as an
alternative to a magazine of individual sheets is disclosed in my
copending U.K. patent application No. 48186/72.
In a long production run, it is necessary to switch over from one
supply reel to another, when the one supply reel is about to become
empty. In the absence of a special device enabling the
switching-over to another supply reel to take place quickly and in
synchronism with the other parts of the packaging machine, it might
well be necessary to shut down the entire machine in order to fit a
new reel of continuous web material. It may thus be desirable to
ensure mutual correlation between the webs from the respective
supply reels. The web material in question may, for example,
comprise paper or viscose or cellulose film.
One form of cutting device which enables such a synchronised switch
to take place from one supply reel to another is disclosed in my
co-pending United Kingdom patent application no. 50094/72. The
present invention provides an alternative device to that disclosed
in that patent application.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a device for
cutting continuous webs into lengths, comprising two web feed paths
each having a portion common to the other, respective cutter means
associated with each feed path, respective web feeder means
selectively operable to feed a web past the respective cutter means
in co-ordination with the displacement of a displaceable knife
element thereof, and web change-over means selectably actuatable to
render inoperative substantially simultaneously said feeder means
and said cutter means associated with one feed path and to render
operative substantially simultaneously said feeder means and said
cutter means associated with the respective other feed path, said
feeder means and said cutter means associated with the one path
being rendered inoperative only on the displaceable knife element
of the respective cutter means being in a predetermined position,
the arrangement being such that, in use, the web change-over takes
place when the leading edges of respective webs are each so located
at corresponding leading edge registration positions in the
respective feed paths, that, on the change-over means being
actuated, the first length severed from the respective other web is
displaced along the common feed path portion in substantially the
same time interval as a length severed from the one web would have
been had the change-over means not been actuated.
The web feeder means may comprise one or more pairs of drive
rollers in the respective feed paths, through the nip of which the
respective web passes to the respective cutter.
As the severed lengths pass along the common portion of the feed
paths, they may travel for example in a vertically downward
direction.
Each cutter preferably comprises a rotary cutter having one
stationary knife element and a further knife element rotatable
relatively to the stationary knife element to bring cutting means
of the two knife elements into mutually co-operative action. The
rotatable knife elements may be so mounted and driven, only one of
them being driven at any given time, that they rotate continuously,
for example at uniform speed, or so that they execute individual
single rotations spaced by periods of rest. Appropriate drive means
for the rotatable knife elements are, of course, provided in either
case.
The cutting device may be so arranged that the cut lengths of web
produced by the operating cutter are fed from the cutter following
closely, i.e. substantially in contact, on one another, or if
desired, a gap may be introduced between the trailing edge of any
one of the cut lengths and the leading edge of the next following
length. The latter result may be achieved by introducing suitable
differences of linear speed along the feed path, between different
parts of the drive means provided to feed the web along the
respective feed paths. For example, a conveyor belt arrangement,
such as an arrangement incorporating a permeable conveyor belt
operating by suction may be situated downstream of the cutter in
each of the feed paths, and this arrangement may be operated at a
higher speed than that of a pair of rollers provided to draw the
continuous web of material from the supply reel. If desired, a pair
of auxiliary feed rollers may be provided upstream of the conveyor
belt arrangement and downstream of the cutter.
If desired, a clutching arrangement may be provided, to transfer
drive from a drive shaft selectably to either one of the two
rotatable members of the cutters, each of the rotatable members
being coupled to a respective helical gear wheel, bevel gear or
other suitable gearing arrangement which is in turn connected to a
respective co-operable gear mounted about the drive shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
Two embodiments of this invention will now be more particularly
described with reference to the accompanying drawings, in
which:
FIG. 1 shows a sectional view, in a vertical plane, through one
embodiment of the device of the invention; and
FIG. 2 shows a similar sectional view of a second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, two continuous webs 14 and 114 of film material are
shown in heavy lines, the first travelling in a rightward and
downward direction from the top left-hand part of the Figure, and
the second travelling downwardly and to the left from the top
right-hand part of the Figure. The two webs 14 and 114 are drawn by
drive means in the form of pairs 1 and 101 respectively of drive
rollers from respective supply reels (not shown). At any given
time, only one of the two webs is fed through the device, which is
so designed that the feed may be switched over from one web to the
other, provided that the second web is threaded into the device and
located at the appropriate position, for example in synchronism
with the speed of operation of any other device to which the webs
are fed after cutting.
As far as the components of the device below the drive rollers 1
and 101 are concerned, the device is fully symmetrical about a
central vertical axis which forms an upward continuation of a line
13 which denotes a cut length of web being drawn out of the cutting
device by driven rollers 12. For this reason, only the components
on the left-hand side of the axis will be described in detail,
similar reference numerals to those of these components being
employed to indicate the corresponding components on the right-hand
side of the axis, but with 100 added.
Downstream of the pair of drive rollers 1 is a rotary cutter which
has a stationary knife element 2 and a rotatable knife element 3.
FIG. 1 shows these knife elements in their position of co-operating
action to cut the continuous web 14. The direction of rotation of
the rotatable knife element is shown by an arrow (this is
anti-clockwise in FIG. 1). At 3a there is shown another position of
the rotatable knife element 3, i.e., the position diametrically
opposed to that shown in solid lines in FIG. 1, the position 3a
being indicated in chain-dotted lines. The importance of the
position 3a will be explained later. Downstream of the rotary
cutter is a suction conveyor belt arrangement, which has a conveyor
belt 5 permeable to air, circulating around a pair of rollers 4 and
7. Inside the loop formed by the conveyor belt 5, a suction chamber
6 is situated, which has a wall in contact with the belt, the wall
being perforated as shown. As a result of suction applied to the
chamber 6, the web 14 is held firmly against the outer surface of
the conveyor belt 5, to prevent the web from flapping or falling
away. From the conveyor belt 5, the web 14 passes through the nip
between a further pair of rollers 8, and thence through the nip
between a pair of rotatable annular portions 9 and 109 of a suction
roller arrangement. The annular portions 9 and 109 are each
rotatable respectively relatively to stationary portions 11 and
111, in which there is defined a suction chamber, 10 and 110
respectively. Each of the annular portions 9 and 109 is perforated
by bores extending in a direction radial of the axis of rotation of
the respective annular portion, so that while a web is in the
vicinity of the nip between the two annular portions the web is
held firmly by suction against the radially outer surface of one or
both, as the case may be, of the two annular portions. From the
suction roller arrangement, the web passes vertically downwardly
through the nip between two further drive rollers 12.
The mechanism for transferring drive output from the rotatable
knife element 3 to the rotatable knife element 103 will now be
described. This is shown at the top of FIG. 1, and includes a drive
shaft 25. Rigidly connected with the drive shaft is a portion of
enlarged diameter shown at 20, 120, which is provided with a guide
projection 22 secured against lateral movement in a guide member 23
which is stationary, i.e. which does not rotate with the shaft 25.
The rotatable knife element 3 is connected with a helical gear 16,
which can mesh with a co-operable gear 15 mounted on an elongate
member 18 about the drive shaft 25. The elongate member 18 is
provided at each opposite axial end with engagement jaws and is
rotatably mounted on the drive shaft 25. The left-hand engagement
jaws are shown in FIG. 1 as being spaced from co-operable
engagement jaws of a stationary part 17 of a support in which the
drive shaft 25 is rotatably mounted. The right-hand engagement jaws
of the elongate member 18 are shown in a position in which they are
engaged with co-operable left-hand engagement jaws of the portion
20, 120 rigidly connected to the drive shaft 25. Similar jaws at
the right-hand axial end of the portion 20, 120 are spaced from
co-operable jaws at the left-hand axial end of a further elongate
member 119, which is similar to the elongate member 18. The member
119 is likewise mounted about the drive shaft 25 and is free to
rotate relatively thereto. A gear 115, similar to the gear 115, is
carried by the member 119 rigidly. The right-hand end of the member
119 is designated by 118. Engagement jaws at the right-hand axial
end of the member 118 engage complementary jaws at the left-hand
end of a stationary part 117 of the support in which the drive
shaft 25 is rotatably mounted.
In the condition of the device shown in FIG. 1, when the drive
shaft 25 rotates no drive is transmitted to the gear 115, and thus
the rotatable knife element 103 is not driven. The reason for this
is that there is no drive connection between the part 20, 120 and
the elongate member 119. Furthermore, the right-hand axial end jaws
of the member 119 are in firm engagement with the part 117, which
is stationary at all times.
On the other hand, upon rotation of the drive shaft 25, drive is
transmitted to the elongate member 18, as a result of the
engagement between the jaws of the member 18 and the portion 20,
120. As a result, the gear 15 and thus the gear 16 and the
rotatable member 3 are driven. An elongate displacement member 24
is mounted in the support, and is provided with two recesses each
to receive a portion of a respective one of the two gears 15 and
115, as shown.
When it is desired to transfer the drive output of the drive shaft
25 from the rotatable member 3 to the rotatable member 103, i.e. to
disconnect the left-hand cutter and to connect the right-hand
cutter, a leftward displacement is imparted to the displacement
member 24. This moves both of the gears 15 and 115 to the left,
thereby disengaging the member 18 from the rotating portion 20, 120
and connecting it to the stationary member 17. At the same time,
the member 119 is disconnected from the stationary member 117 and
connected to the rotating member 20, 120, at the opposite axial end
thereof from that at which the member 18 was previously connected.
In the embodiment illustrated in FIG. 1, the ratio of the gearing
provided by the gear 15, 16 and 115, 116 is 1:1. Thus, the
rotatable knife elements of the cutters are rotated in synchronism
with the rotation of the drive shaft 25. Constraining means in the
form of the mutually co-operating dog clutch means or jaws on the
axial ends of the members 17, 18 and 117, 118 are so arranged that
they are only coupled together at the instant when the knife
element is in the positions 3a, 103a. Thus, when the pushable
displacement member 24 is urged to the left in FIG. 1, the
change-over of the application of drive to the rotatable knife
elements 103 only takes place when the latter is in the position
103a. At this instant, the co-operable jaws on the elements 17, 18
mutually inter-engage and cause the rotatable knife element 3 to be
brought to a standstill at the position 3a. At the same time as
this interengagement takes place, the switch 21 is actuated to
cause the rollers 1 to stop rotating and the rollers 101 to start
rotating in synchronism with the rotation of the rotatable cutter
member 103.
A switch contact 21 is provided to the left of the displacement
member 24. Upon a leftward displacement of the member 24 from the
position shown in FIG. 1, the plunger of a two-way switch 21
becomes depressed, to cause the contacts of the switch 21 to
disconnect the drive to the rollers 1, and to cause the switch
contacts to establish the drive to the rollers 101. Conversely,
when the actuator plunger of the switch 21 is not depressed (that
is when the switch 21 is in the condition illustrated in FIG. 1)
the rollers 1 are driven and the rollers 101 are stationary. Any
suitable form of transmission devices such as electro-magnetic
clutches may be employed to be operated by the switch contact 21.
However, if desired, the rollers 1 and 101 may be independently
driven. In these circumstances, each of the independent drive means
is controlled via a control circuit including the switch 21.
The operation of the embodiment shown in FIG. 1 will now be
described. In the condition of the device shown in FIG. 1, it is
the web 14 which is being fed through the device. When the leading
edge of the web reaches the point C', the rotatable knife member 3
co-operates with the stationary knife member 2 to make a cut
through the web. If it is now described to switch over to the web
114 on the right-hand side of the device, the displacement member
24 is actuated by pushing it to the left to disconnect the drive to
the rotatable member 3, so that the latter comes to a standstill at
the position 3a. At the same time, the drive rollers 1 are
disconnected. The actuation of the displacement member 24 also
causes drive to the rotatable member 103 (which at the relevant
moment is stationary in position 103a), to be established, and this
starts now to rotate in the clockwise sense in FIG. 1. At the same
time, as a result of the depression of the switch contact 21, the
drive rollers 101 are switched on. When the left-hand rotatable
member 3 has come to rest, the leading edge of the web 14 has
reached the position shown at D, this position being a leading edge
registration position. The accurate positioning of the leading edge
of the left-hand web results from the rotatable cutter 3 being
rotated in co-operation with the web drive rollers 1. Thus, since
the rotatable knife element 3 is brought to rest at 3a and the
drive rollers 1 are arrested at the same moment by the actuation of
the switch 21, the leading edge of the left-hand web is arrested
when it reaches the corresponding leading edge registration
position D. It is important to ensure that when the drive to the
rollers 101 is established the leading edge of the stationary web
114 is at the corresponding leading edge registration position
(also shown by letter D in FIG. 1), so that after the change from
one supply reel to the other has been completed the first length
cut from the second web passes out of the device in the same time
sequence after the last length cut from the first web as if the
first length cut from the second web had in fact been cut from the
first web.
The above sequence of operations takes place on the assumption that
linear speed of all the various driving and conveying elements,
measured along the appropriate feed path, is the same. With such an
arrangement, it is clearly possible, if desired, to drive all the
components from a common drive source. However, this arrangement
results in cut lengths of web being discharged from the cutting
device with no gap in between, i.e. the leading edge of any given
cut length of web follows closely, or substantially in contact, on
the trailing edge of the next preceding cut length.
In some cases, it may be desired that a gap should be provided
between the trailing edge of any given cut length and the leading
edge of the next following cut length. This may be achieved with
the embodiment of FIG. 1 by applying the principle of the
embodiment of FIG. 2 to be described below.
When the rotatable member 3 is at rest in position 3a, a half
length of web material extends between position A and position D.
As mentioned above, this is supported by the suction effect
provided by the permeable conveyor belt 5 and the associated
equipment. However, additional means may be provided, if desired,
for supporting this length of material, for example a magnetically
operated holder, in which case the suction applied to the suction
chamber 6 may be switched off.
Of course, between the various components of the cutting device
shown in FIG. 1, the requisite guides, for example in the form of
rails, transfer bridge members or additional belts etc. are
provided as desired. These are not shown in the drawing, for the
sake of clarity.
It is clear from the above description of the drive shaft 25 and
the associated equipment that at all times one of the gears 15 and
115 is maintained stationary by its connection to a stationary part
of the support, and the other is connected rigidly with the drive
shaft 25 for rotation therewith. A single stroke of the
displacement member 24 for example produces a permanent change-over
from one supply reel to the other. The member 24 may be manually
displaced by an operator if, for any reason, it is desired to
change the web supply at any time. Alternatively or additionally,
the member 24 may be coupled to means for sensing when one of the
supply reels is approaching its emptied state. In these
circumstances, the web change-over may take place automatically.
Preferably, the mechanism for displacing the member 24 is arranged
to resiliently urge the menber 24 towards the right or the left, as
the case may be, in order to enable the coupling between the
co-operating dog clutch jaws to take place smoothly at the
appropriate moment. Because the characteristics of this coupling
such as that between the members 17, 18 for example, the rotatable
cutter is always arrested at the position 3a or 103 a. However, if
a new web is to be introduced, it will either be necessary to
splice the new web to the trailing end of the old exhausted web, or
to manually feed the new web to the position in which it is in
registration with the corresponding leading edge registration
position.
The rotational position at which the jaws of the member 18 engage
with the co-operating jaws on the member 17 is determined by the
positioning of the stationary jaws on the latter member. Thus,
provided that the web is driven by the roller pairs 1, 101 in
co-ordination with the rotation of the respective rotatable member
bearing the knife elements 3, 103, the position at which the knife
element is brought to rest may be preset to any convenient
position. Thus, the knife element 3 may be arrested in a position
other than 3a, and thus will result in the location of the leading
edge registration position being shifted correspondingly. Of
course, the arrested positions of the knife elements 3 and 103 must
correspond with one another, if the first web piece cut from the
second web -- after a web change-over has been initiated -- is to
be fed from the machine in substantially the same time interval as
the corresponding web piece cut from the first web would have been
if the change-over had not been initiated.
Advantageously, the co-operating jaws on the members 17, 18, 19,
20, 120, 119, 118 and 117 are in the form of dog-clutches. The dog
clutch components are so arranged that they may be coupled together
only when the shaft 25 is in a uniquely identified angular position
in each revolution.
Although, in the preferred embodiment the slidable sleeves are
coupled to the respective cutter means by co-operating gears 15, 16
and 115, 116, other means for coupling the drive shaft 25 to the
mobilized cutter may be employed for this purpose. However, it is
necessary for the displaceable knife elements of the respective
cutter means -- which may be reciprocatable knife elements -- to be
displaced in co-ordination with the drive shaft and the respective
web feeder means such as the nip roller pairs 1, 101.
With the above described arrangement mistakes in cutting and the
spoiling of clean cut edges by snipping by the cutters are for
practical purposes avoided.
The embodiment shown in FIG. 2 discharges cut lengths of web
material which, instead of following very closely one on the other,
follow with a gap in between. As mentioned above, this may be
advantageous in the supply of lengths of wrapper to cigarette block
packaging machines.
The embodiment shown in FIG. 2 will now be described. However, the
basic arrangement is very similar to that shown in FIG. 1.
The parts of the device enclosed in chain-dotted lines and labelled
I, II and III respectively may conveniently be considered
separately. The moving parts shown in part I of the device operate
at all times when the cutting device is in operation, while the
moving parts of part II of the device are driven only when a web 24
is being supplied from a left-hand supply reel (not shown), and the
moving parts of part III of the device are driven only when a web
1234 is being fed from a right-hand supply reel (not shown). In
part II of the device, a pair of drive rollers 1 draw the web 24
from the left-hand supply reel, and the web 24 passes through the
nip between the two rollers 1, and then between two transfer bridge
members 5 and 6. A rotary cutter is provided downstream of the
rollers 1, and has a stationary knife element 2 and a co-operating
rotary knife element 3. In chain-dotted lines there is shown the
position of the knife element 3 in which a cut is taking place. A
further position for the knife element 3 is shown at 3a, in which
the knife element 3 has executed a 90.degree. rotation from the
position shown in chain-dotted lines. After passing through the
cutter, the cut lengths of web material pass between a tail section
of the bridge member 6 and a further bridge member 7, to teach the
nip between two auxiliary drive rollers 4, whence the cut length of
web pass between a still further bridge member 13 and a guide plate
of generally triangular configuration with its apex downwards.
The part III of the device contains similar components to those of
the part II, and these are represented by similar reference
numerals, but with 100 added. In addition, there is shown in part
III of the device a further position 103b of the rotatable knife
element 103 of the rotary cutter in part III, the position 103b
being the diametrically opposite position to that in wich the
rotatable knife element co-operates with the stationary knife
element 102 to make a cut. As shown by the arrow in part III, in
operation the rotatable knife element 103 rotates in the clockwise
sense in FIG. 2.
Against the lower surface of the web 24 after reaching part I of
the device, there acts a permeable conveyor belt 9, generally
similar to the belt 5 described in connection with FIG. 1, and the
belt 9 passes around the left-hand roller of a suction roller
arrangement similar to the arrangement 11, 111 of FIG. 1 and also
around a further roller 25. A suction chamber 11 is provided inside
the loop formed by the belt 9, and a housing wall 10 of the chamber
is perforated with apertures extending towards the belt 9 as shown
in FIG. 2. The suction effect applied by the suction chamber 11
through the belt 9 holds the web 24, after cutting, securely
against the belt 9 as the web is conveyed to the nip between the
two annular rollers of the suction roller arrangement. Numeral 12
denotes the opposite wall of the suction chamber. Lateral guides 14
are provided to maintain the conveyor belt 9 on its intended course
as it executes its return run. The suction chambers of the suction
roller arrangement are shown at 26 and 126.
Additional transfer bridge members 17 are provided downstream of
the suction roller arrangement, and a further pair of drive rollers
18, 19 are provided to draw cut lengths of web material out of the
cutting device. Around the roller 19 there passes a further,
similar permeable conveyor belt 20, a suction chamber 23 being
provided to act on this belt. The rear wall of the suction chamber
is shown at 22, and the front, perforated wall at 21. The lateral
guides for the belt 20 are shown at 27.
Not every component of part I of the device has been described in
detail, since the components of this part of the device on the
right-hand side along the path of the conveyor belt 109 are similar
to those on the left-hand side along the path of the conveyor belt
9. 100 has, however, been added to the corresponding reference
numerals.
The operation of the embodiment shown in FIG. 2 will now be
described.
A and B denote corresponding points along the paths of the webs 24
and 124 respectively. At the moment when part III of the device,
after operation for a period of time, is brought to a standstill
and part I is set into motion because it is desired to switch over
from the web 124 to the web 24, it is arranged that the leading
edge of the web 124 stops at the position B, which is a leading
edge registration position. In these circumstances, the rotatable
knife element 103 stops in position 103a. The trailing edge of the
last length cut by the cutter 102, 103 from the web 124 is at
position D, since this length is drawn through part I of the device
at a speed exceeding that at which it is drawn through part III. To
achieve this, the conveyor belt 109 is driven at a higher linear
speed, measured along the feed path, than the rollers 101 and 104.
Thus a gap is formed between the trailing edge D and the leading
edge B. The device can be so operated that such a gap is formed not
only at the time of changing over from one supply reel to another,
but all the time, so that each of the cut lengths of web is fed
with a spacing from the preceding length and the following length.
The provision of such a gap is certainly not necessary, but in some
circumstances is advantageous. However, if desired, the conveyor
belt 109 may be caused to increase in speed in relation to the
components of part III of the device only at the time of changing
over from one supply reel to another.
From E, the cut length is discharged from the cutting device, to be
utilised for packaging purposes, for example to be wrapped around a
cigarette block.
The arrangement of the drive shaft (denoted by the reference 25 in
FIG. 1), the displacement member (denoted by the reference 24 in
FIG. 1), and the associated clutching members and gears is the same
in the embodiment of FIG. 2 as in that of FIG. 1. For this reason,
these components are not shown in FIG. 2, for the sake of
clarity.
Althought the embodiment shown in FIG. 2 has the advantage of
introducing gaps between the successively discharged cut lengths of
web material, nevertheless the device may be produced economically
and the construction is not particularly complicated. However, this
embodiment may be operated in a particularly effective manner.
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