CA1104783A - Method and apparatus for processing synthetic plastics film - Google Patents
Method and apparatus for processing synthetic plastics filmInfo
- Publication number
- CA1104783A CA1104783A CA282,215A CA282215A CA1104783A CA 1104783 A CA1104783 A CA 1104783A CA 282215 A CA282215 A CA 282215A CA 1104783 A CA1104783 A CA 1104783A
- Authority
- CA
- Canada
- Prior art keywords
- web
- weakness
- series
- slot
- synthetic plastics
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B26—HAND CUTTING TOOLS; CUTTING; SEVERING
- B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
- B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
- B26F1/18—Perforating by slitting, i.e. forming cuts closed at their ends without removal of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B26—HAND CUTTING TOOLS; CUTTING; SEVERING
- B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
- B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
- B26D7/08—Means for treating work or cutting member to facilitate cutting
- B26D7/10—Means for treating work or cutting member to facilitate cutting by heating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B2155/00—Flexible containers made from webs
- B31B2155/001—Flexible containers made from webs by folding webs longitudinally
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B2155/00—Flexible containers made from webs
- B31B2155/001—Flexible containers made from webs by folding webs longitudinally
- B31B2155/0014—Flexible containers made from webs by folding webs longitudinally having their openings facing transversally to the direction of movement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31B70/00—Making flexible containers, e.g. envelopes or bags
- B31B70/74—Auxiliary operations
- B31B70/92—Delivering
- B31B70/94—Delivering singly or in succession
- B31B70/946—Delivering singly or in succession the bags being interconnected
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Forests & Forestry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Making Paper Articles (AREA)
- Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
- Medical Treatment And Welfare Office Work (AREA)
- Wrappers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A web of synthetic plastics film, having a series of panels separated by longitudinally spaced transverse zones of weakness extending across the width of the web. The zones of weakness are constituted by a series of heat-produced per-forations along the lengths of the zones. Adjacent perforations are separated by unperforated portions of the web. When the web is a double layer then the panels are in the form of bags, the layers being sealed at the sides of the bags at the per-forations in the zones of weakness.
A machine for making the web, causes a web of synthetic plastics material to pass longitudinally past a transverse hot cutting and welding edge which cyclicly inter-sects the web at longitudinally spaced intervals. The hot cutting and welding edge has a series of interruptions along its length.
A web of synthetic plastics film, having a series of panels separated by longitudinally spaced transverse zones of weakness extending across the width of the web. The zones of weakness are constituted by a series of heat-produced per-forations along the lengths of the zones. Adjacent perforations are separated by unperforated portions of the web. When the web is a double layer then the panels are in the form of bags, the layers being sealed at the sides of the bags at the per-forations in the zones of weakness.
A machine for making the web, causes a web of synthetic plastics material to pass longitudinally past a transverse hot cutting and welding edge which cyclicly inter-sects the web at longitudinally spaced intervals. The hot cutting and welding edge has a series of interruptions along its length.
Description
11~)47~3 THIS INVENTION relates to a method and to apparatus for perforating synthetic plastics film. It relates more particularly to the making of bags from synthetic plastics film.
In accordance with the invention, a method of making bags in a continuous web of synthetic plastics film comprising a series of bags separated by a series of longitudinally spaced transverse zones of weakness, includes-providing a double layer web of folded heat-sealable synthetic plastics film;
displacing the web in a longitudinal direction along the direction of the fold; and cyclically providing longitudinally spaced transverse zones of weakness by causing a transverse hot-cutting edge having a series of interruptions spaced along its length to move with and to perforate the web while it is moving to seal the layers of the web together at longitudinally spaced intervals trans-versely to the fold, thereby leaving unsealed lands at interruptions between the perforations in the zone of weakness for holding ad~acent bags together;
the web, as it moves, spanning slot-defining means moving in unison with the web; and the hot-cutting edge moving longitudinally at the same rate as the web and the slot-defining means, and also moving cyclically lnto the slot to intersect the web and then out of the slot.
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,. : . ' , ~. .
~1~47~33 The perforations may be long and the unsealed holdi.ng lands which lie between perforations and which hold adjacent panels together, may be short. The length of a perforation may be between ten and one hundred and fifty times the length of an adjacent land.
The double layer may be open along one longitu-dinal edge and the longitudinal edge of ~he one layer may project transversely beyond the longitudinal edge of the other layer.
Apparatus.for carrying out the method as described includes (a) a slot-defining means defining at least one slot, and being adapted to receive a double layer of web of synthetic plastics material, the web being adapted in operation to seat on the slot-defining means and to span the slot;
(b) displacing means adapted to displace both the slot-defining means and the web in contact therewith in unison in a direction transverse to the length of the slot;
.
(c) a heat cutter member spaced from the slot defining means to permit the web to pass between them and having an elongated heatable cutting edge e~tending in a direction parallel to-the length of the slot and having spaced interrup~ions along the length of its heatable cutting edge; and (d) a heat cutter member displacing means adapted in operation to displace the heat cutter member operatively to cause its heated cutting edge to intersect the web and to enter the slot and to move in unison with and in the same direction as the web and slot and thereafter to disengage from the web and the slot.
The slot~defining means may define a spaced series of transverse slots and the heat cutter member displacing means may be arranged to displace the heat cutter member operatively in cyclic to and fro fashion. The slot-defining means may comprise a drum mounted to rotate about its axis, the drum having the series of slots spaced circumferentially in its periphery.
The product of the method is a continuous double la~er web of synthetic plastics film in roll form and comprising a series of panels in the form of bags separated by a series of longitudinally spaced transverse zones of weakness extending across the width of the web, each zone of weakness comprising a series of heat-produced elongate perforations in the web separated by trans~ersely spaced holding lands holding adjacent panels together, the two layers of film being sealed together along the lengths of the perforations, but being unsealed and separate at the holding lands bet~een perforations.
.
~. .
.~ .
The web may be in roll form.
The i.nventi.on will now be described by way of example ' , with refexence to tlle accompanying diagrammatic drawings.
. In the drawings Figure l shows an oblique end view of apparatus according to the invention;
Figuxe 2 shows a cross-sectional end elevation of thc apparatus shown in Yigure 1;
Figure 3 shows a fragmentary front elevation of one end of the drum of the apparatus shown in Figures 1 and 2 of the drawings;
Figure 4 shows a fragmentary section taken at IV-IV
in Figure 3 of the drawings;
Figure S shows a fragmentary front elevation o. a heat cutter member of the apparatus shown in Figures ]. and 2 of the drawings;
Figure 6 shows ~n underside plan view of the heat cutter member of Figure 5;
Figure 7 shows a fragmentary cross-section at VII-VII
of the heat cutter member of Figure 5, when in position inter-secting a web on a slotted drum;
Figure 8 shows a fragmentary cross~section at VIII-VIII of a web shown in Figure 9;
Figure 9 shows a fragmentary plan view of a web in the region of its zone of weakness;
Figure lO shows a fragmentary lonyitudinal section at X-X in Fiure 9;
Fiyure 11 shows a frotlt elevdtion of a web in roJ.l form when muunted about a hori.zontal axis; and Figure 12 shcws a front elevati.on of a web in roll form whell moun'Led about a vertical axis.
Referring to Figures 1 and 2 of the drawings, there is shown apparatus according to the invention gcnerally indicated by reference numeral 10. The apparatus comprises a frame 12 rotatably supporti.ng slot-defining means in the form of a slotted drum having a series of slots 16 spaced circumferenti.ally in the periphery of the drum. The drum 14 is mounted to rota~e in the direction of arrow 17 about the axis of the shaft 18. It receives its drive from a drive wheel 20 which engages also with a take-up roller 22 engag.ing with an idler 24 which meshes in turn with a take-up roller 26.
A web 28 of synthetic plastics film unwound from roll 30, is caused to pass over deflecting rollers 32, thence over the drum 14 under a heat cutter sealing member 34 extending between a pair of opposed forks 36 provided at opposite ends of the drum 14. The heat cutter sealing member 34 is provided with displacing means partly shown by reference numeral 38, and which is adapted to displace the heat cutter sealing member 34 in a to and fro and up and down direction in a closed loop as the drum 14 rotates in the direction of arrow 17. In so doing, the web 28 passes longitudinally through the machine from left to right.
The heat cutter sealing member 34, intersects the web cyclically at longitudinally spaced zones. In doing so, the heat cutter member 34 provides a seri,es of longitudi]lally spaced ZOlleS of weakness in the web 28. The various zones of weakness separate panels in the web, and the weh having these zones of weakness, is then taken up in roll form as indicated at 40 carried on arms 42 slidab]e in guides 44. The roll 40 is caused to rotate in the direction of arrow 40.1 by means of the rollers 22 and 26 rotating in the direction of the arrow as indicated in Figure 2.
The heat cutter member, has a cutting edge 34.1. The heat cutter member and its operation will be described more fully hereafter.
Referring now to Figures 3 and 4 of the drawings, there are shown fragmentary details of the end of the drum 14. At the end of the drum 14, and closely axially spaced therefrom, there is providea a gear wheel 50, having a nun~er of teeth corresponding to the number of slots 16 in the drum 14, the spaces between the teeth, being axially aligned with the slots ; 16 in the drum 14~ Furthermore, the fork 36 is provided with a tooth 52 axially aligned with the heat cutter member 3~ sup~
ported between the axially spaced opposing forks 36 straddling the shaft 18 of the drum 14. The tooth 52 is adapted to engage cyclically between the teeth of the gear wheel 50 thereby ensuring that the heat cutter member 34 will enter accurately into the slots aligned with the spaces engaged by the tooth 52. The tooth 52, and hence the heat cutt,er member 34, being displaced by the displacing means, follow a closed loop path when viewed in the direction of Figure 4 of the drawings. '~
Referri.ng to ~`igures 5, 6 and 7 of the drawi.ngs, the heat cutter member, is shown in greater deta.il. It has a heati.ng cutting eclge 34.1 which, when hot, will intersect and seal ~leb 28 as it l.ies on the drum 14. The hot cutting edge 34.1, will pass through the web 28, and enter the slot 16. The cut.ting edge 34.1 is provided with interruptions 34.2. The length of an interruption 34.2 in the cutting edge 34.1, may be of the order of a few mi.llimetres say one or two millimetres. The distance between interruptions, may vary from about 20 mm to about lOQ or 150 mm. The total length of the interruptions may be of the order of ~ ~v ~ ~ of the total length of the heating cutting edge of the heat cutter member 34.
Referring now to Figures 8, 9 and 10 of the drawings, there are shown details of a double layer web of synthetic plastics material, after a zone of weakness has been provided in it. The hot cut.ting edge 34.1 of the heat cutter member 34, when it intersects the web 28, provides a zone of weakness 60 extend-ing transversely to the direction of movement of the web through the machine 10. The zone of weakness 60 is constituted by a p].urality of perforations 60.1 separated by lands 60.2 holding adjacent panels 28.1 and 28.2 together. These panels, are separated by the zone of weakness 60. The lands 60.2 are provided by the interruptions 34.2 in the cutting edge of the heat cutter memher 34. The cutting edge of the heat cutter member 34, at the interruptions 34.2, are provided with sharp edges, so as to ensure that the lands 60.2 between adjacent perforations 60.1, will have w~ ~ This will ensure that the panels will separate - at the- ~ along the zone of weakness, when pulled apart.
:
478~
- The upper and lower layers 28.11 and 28.12 of .- par.e:L
28.1 will ~)ecome fused together at the zone 62 in the perfoxation 60.1. When in opeLation, the heat cutt:er melnber 34 will be maintained at a suitable temperature in order to ensure effec-tive cutting oi the web, and effective welding of the upper and lower layers 28.11 and 28.12, and of corresponding layers of other panels. The heat cutter sealing member 34 will be electrically heated. The displacing means 38 will be driven in synchronism with the drum 14, and the remaining rollers 20, 22, 24 and 26.
Referring now to Figures 11 and 12 of thc drawings, after the web has been taken up in roll form 40, as indicated in Figures 1 and 2 of the drawings, the rolls are removed and mounted as shown in Figures 11 and 12 of the drawings, for use.
The roll 40 may be mounted to be rotatable about the axis of a horizontal shaft 70, the various panels 28~1, 28,2 and 28,3, being separated by zones of weakness 60. The zones of weakness are provided by a series of perforations 60.1, spaced across the width of the web 28. The perforations are separated by the lands 60.2. The web in roll form 30 is in a double layer folded over at the longitudinal edge 40.11 and is open at the longitudinal edge 40.2. The edge 40.21 of one layer extends transversely beyond the longitudinal edge 40.22 of the other layer of the roll 40.
- Figure 12 shows an alternative way of mounting the ;
roll 40. In this embodiment, the roll 40 is mounted about the axis of a rod 72 fast with a base 74 resting on a support 76.
7~33 In practice, where a machlne i5 of substantial width, it will be posc;ible ~o have a plurality of rolls 30 processed at the same time, for the production of rolls 40. The rolls 40 wilL thcn be produced side by side, as shown in Figure 1.
~urthermore, the apparatus can also ~orm part of an in-line installation having a printing machine and an extruder upstream of the apparatus according to the inventlon, The drum 14 and its associated rollers, will be driven in synchronism with the upstream printing installation and the extruder.
The applicant has found that side sealed plastic bags can have adequate strength for most purposes, for example, for the packing of merchandise in shops. The applicant has also found that for most purposes the bags do not have to be airtight. Indeed, for some purposes it is advantageous if they are not airtight.
Accordingly, bags made in accordance with the invention can be utilized in roll form, adjacent bags being held together by the holding lands 60.2. Bags can easily be torn from the roll, separation between adjacent bags taking place along the zones of weakness.
The film used is conveniently low density polyethylene ~film. The bags are easily opened by having one lip 40.22 longer than the other lip 40.21. ~ ;
' -10- . I
. ~!
.
- , ~ having a thickness of between 5 microns and 100 microns can be processed in accordance with the inventi.on.
Besides, low density polyethylene film, film of o-ther materials, can also be processed in the manner.according to the invention.
Thus, polypropylene film, high density polyethylene film, ri.gi.d . polyvinylchl.ori.de film, ie without plasticiser, can all be processed in the manner of the invention.
, . .
In accordance with the invention, a method of making bags in a continuous web of synthetic plastics film comprising a series of bags separated by a series of longitudinally spaced transverse zones of weakness, includes-providing a double layer web of folded heat-sealable synthetic plastics film;
displacing the web in a longitudinal direction along the direction of the fold; and cyclically providing longitudinally spaced transverse zones of weakness by causing a transverse hot-cutting edge having a series of interruptions spaced along its length to move with and to perforate the web while it is moving to seal the layers of the web together at longitudinally spaced intervals trans-versely to the fold, thereby leaving unsealed lands at interruptions between the perforations in the zone of weakness for holding ad~acent bags together;
the web, as it moves, spanning slot-defining means moving in unison with the web; and the hot-cutting edge moving longitudinally at the same rate as the web and the slot-defining means, and also moving cyclically lnto the slot to intersect the web and then out of the slot.
~?
,. : . ' , ~. .
~1~47~33 The perforations may be long and the unsealed holdi.ng lands which lie between perforations and which hold adjacent panels together, may be short. The length of a perforation may be between ten and one hundred and fifty times the length of an adjacent land.
The double layer may be open along one longitu-dinal edge and the longitudinal edge of ~he one layer may project transversely beyond the longitudinal edge of the other layer.
Apparatus.for carrying out the method as described includes (a) a slot-defining means defining at least one slot, and being adapted to receive a double layer of web of synthetic plastics material, the web being adapted in operation to seat on the slot-defining means and to span the slot;
(b) displacing means adapted to displace both the slot-defining means and the web in contact therewith in unison in a direction transverse to the length of the slot;
.
(c) a heat cutter member spaced from the slot defining means to permit the web to pass between them and having an elongated heatable cutting edge e~tending in a direction parallel to-the length of the slot and having spaced interrup~ions along the length of its heatable cutting edge; and (d) a heat cutter member displacing means adapted in operation to displace the heat cutter member operatively to cause its heated cutting edge to intersect the web and to enter the slot and to move in unison with and in the same direction as the web and slot and thereafter to disengage from the web and the slot.
The slot~defining means may define a spaced series of transverse slots and the heat cutter member displacing means may be arranged to displace the heat cutter member operatively in cyclic to and fro fashion. The slot-defining means may comprise a drum mounted to rotate about its axis, the drum having the series of slots spaced circumferentially in its periphery.
The product of the method is a continuous double la~er web of synthetic plastics film in roll form and comprising a series of panels in the form of bags separated by a series of longitudinally spaced transverse zones of weakness extending across the width of the web, each zone of weakness comprising a series of heat-produced elongate perforations in the web separated by trans~ersely spaced holding lands holding adjacent panels together, the two layers of film being sealed together along the lengths of the perforations, but being unsealed and separate at the holding lands bet~een perforations.
.
~. .
.~ .
The web may be in roll form.
The i.nventi.on will now be described by way of example ' , with refexence to tlle accompanying diagrammatic drawings.
. In the drawings Figure l shows an oblique end view of apparatus according to the invention;
Figuxe 2 shows a cross-sectional end elevation of thc apparatus shown in Yigure 1;
Figure 3 shows a fragmentary front elevation of one end of the drum of the apparatus shown in Figures 1 and 2 of the drawings;
Figure 4 shows a fragmentary section taken at IV-IV
in Figure 3 of the drawings;
Figure S shows a fragmentary front elevation o. a heat cutter member of the apparatus shown in Figures ]. and 2 of the drawings;
Figure 6 shows ~n underside plan view of the heat cutter member of Figure 5;
Figure 7 shows a fragmentary cross-section at VII-VII
of the heat cutter member of Figure 5, when in position inter-secting a web on a slotted drum;
Figure 8 shows a fragmentary cross~section at VIII-VIII of a web shown in Figure 9;
Figure 9 shows a fragmentary plan view of a web in the region of its zone of weakness;
Figure lO shows a fragmentary lonyitudinal section at X-X in Fiure 9;
Fiyure 11 shows a frotlt elevdtion of a web in roJ.l form when muunted about a hori.zontal axis; and Figure 12 shcws a front elevati.on of a web in roll form whell moun'Led about a vertical axis.
Referring to Figures 1 and 2 of the drawings, there is shown apparatus according to the invention gcnerally indicated by reference numeral 10. The apparatus comprises a frame 12 rotatably supporti.ng slot-defining means in the form of a slotted drum having a series of slots 16 spaced circumferenti.ally in the periphery of the drum. The drum 14 is mounted to rota~e in the direction of arrow 17 about the axis of the shaft 18. It receives its drive from a drive wheel 20 which engages also with a take-up roller 22 engag.ing with an idler 24 which meshes in turn with a take-up roller 26.
A web 28 of synthetic plastics film unwound from roll 30, is caused to pass over deflecting rollers 32, thence over the drum 14 under a heat cutter sealing member 34 extending between a pair of opposed forks 36 provided at opposite ends of the drum 14. The heat cutter sealing member 34 is provided with displacing means partly shown by reference numeral 38, and which is adapted to displace the heat cutter sealing member 34 in a to and fro and up and down direction in a closed loop as the drum 14 rotates in the direction of arrow 17. In so doing, the web 28 passes longitudinally through the machine from left to right.
The heat cutter sealing member 34, intersects the web cyclically at longitudinally spaced zones. In doing so, the heat cutter member 34 provides a seri,es of longitudi]lally spaced ZOlleS of weakness in the web 28. The various zones of weakness separate panels in the web, and the weh having these zones of weakness, is then taken up in roll form as indicated at 40 carried on arms 42 slidab]e in guides 44. The roll 40 is caused to rotate in the direction of arrow 40.1 by means of the rollers 22 and 26 rotating in the direction of the arrow as indicated in Figure 2.
The heat cutter member, has a cutting edge 34.1. The heat cutter member and its operation will be described more fully hereafter.
Referring now to Figures 3 and 4 of the drawings, there are shown fragmentary details of the end of the drum 14. At the end of the drum 14, and closely axially spaced therefrom, there is providea a gear wheel 50, having a nun~er of teeth corresponding to the number of slots 16 in the drum 14, the spaces between the teeth, being axially aligned with the slots ; 16 in the drum 14~ Furthermore, the fork 36 is provided with a tooth 52 axially aligned with the heat cutter member 3~ sup~
ported between the axially spaced opposing forks 36 straddling the shaft 18 of the drum 14. The tooth 52 is adapted to engage cyclically between the teeth of the gear wheel 50 thereby ensuring that the heat cutter member 34 will enter accurately into the slots aligned with the spaces engaged by the tooth 52. The tooth 52, and hence the heat cutt,er member 34, being displaced by the displacing means, follow a closed loop path when viewed in the direction of Figure 4 of the drawings. '~
Referri.ng to ~`igures 5, 6 and 7 of the drawi.ngs, the heat cutter member, is shown in greater deta.il. It has a heati.ng cutting eclge 34.1 which, when hot, will intersect and seal ~leb 28 as it l.ies on the drum 14. The hot cutting edge 34.1, will pass through the web 28, and enter the slot 16. The cut.ting edge 34.1 is provided with interruptions 34.2. The length of an interruption 34.2 in the cutting edge 34.1, may be of the order of a few mi.llimetres say one or two millimetres. The distance between interruptions, may vary from about 20 mm to about lOQ or 150 mm. The total length of the interruptions may be of the order of ~ ~v ~ ~ of the total length of the heating cutting edge of the heat cutter member 34.
Referring now to Figures 8, 9 and 10 of the drawings, there are shown details of a double layer web of synthetic plastics material, after a zone of weakness has been provided in it. The hot cut.ting edge 34.1 of the heat cutter member 34, when it intersects the web 28, provides a zone of weakness 60 extend-ing transversely to the direction of movement of the web through the machine 10. The zone of weakness 60 is constituted by a p].urality of perforations 60.1 separated by lands 60.2 holding adjacent panels 28.1 and 28.2 together. These panels, are separated by the zone of weakness 60. The lands 60.2 are provided by the interruptions 34.2 in the cutting edge of the heat cutter memher 34. The cutting edge of the heat cutter member 34, at the interruptions 34.2, are provided with sharp edges, so as to ensure that the lands 60.2 between adjacent perforations 60.1, will have w~ ~ This will ensure that the panels will separate - at the- ~ along the zone of weakness, when pulled apart.
:
478~
- The upper and lower layers 28.11 and 28.12 of .- par.e:L
28.1 will ~)ecome fused together at the zone 62 in the perfoxation 60.1. When in opeLation, the heat cutt:er melnber 34 will be maintained at a suitable temperature in order to ensure effec-tive cutting oi the web, and effective welding of the upper and lower layers 28.11 and 28.12, and of corresponding layers of other panels. The heat cutter sealing member 34 will be electrically heated. The displacing means 38 will be driven in synchronism with the drum 14, and the remaining rollers 20, 22, 24 and 26.
Referring now to Figures 11 and 12 of thc drawings, after the web has been taken up in roll form 40, as indicated in Figures 1 and 2 of the drawings, the rolls are removed and mounted as shown in Figures 11 and 12 of the drawings, for use.
The roll 40 may be mounted to be rotatable about the axis of a horizontal shaft 70, the various panels 28~1, 28,2 and 28,3, being separated by zones of weakness 60. The zones of weakness are provided by a series of perforations 60.1, spaced across the width of the web 28. The perforations are separated by the lands 60.2. The web in roll form 30 is in a double layer folded over at the longitudinal edge 40.11 and is open at the longitudinal edge 40.2. The edge 40.21 of one layer extends transversely beyond the longitudinal edge 40.22 of the other layer of the roll 40.
- Figure 12 shows an alternative way of mounting the ;
roll 40. In this embodiment, the roll 40 is mounted about the axis of a rod 72 fast with a base 74 resting on a support 76.
7~33 In practice, where a machlne i5 of substantial width, it will be posc;ible ~o have a plurality of rolls 30 processed at the same time, for the production of rolls 40. The rolls 40 wilL thcn be produced side by side, as shown in Figure 1.
~urthermore, the apparatus can also ~orm part of an in-line installation having a printing machine and an extruder upstream of the apparatus according to the inventlon, The drum 14 and its associated rollers, will be driven in synchronism with the upstream printing installation and the extruder.
The applicant has found that side sealed plastic bags can have adequate strength for most purposes, for example, for the packing of merchandise in shops. The applicant has also found that for most purposes the bags do not have to be airtight. Indeed, for some purposes it is advantageous if they are not airtight.
Accordingly, bags made in accordance with the invention can be utilized in roll form, adjacent bags being held together by the holding lands 60.2. Bags can easily be torn from the roll, separation between adjacent bags taking place along the zones of weakness.
The film used is conveniently low density polyethylene ~film. The bags are easily opened by having one lip 40.22 longer than the other lip 40.21. ~ ;
' -10- . I
. ~!
.
- , ~ having a thickness of between 5 microns and 100 microns can be processed in accordance with the inventi.on.
Besides, low density polyethylene film, film of o-ther materials, can also be processed in the manner.according to the invention.
Thus, polypropylene film, high density polyethylene film, ri.gi.d . polyvinylchl.ori.de film, ie without plasticiser, can all be processed in the manner of the invention.
, . .
Claims (10)
1. A method of making bags in a continuous web of synthetic plastics film comprising a series of bags separated by a series of longitudinally spaced transverse zones of weakness, includes providing a double layer web of folded heat-sealable synthetic plastics film;
displacing the web in a longitudinal direction along the direction of the fold;
cyclically providing longitudinally spaced transverse zones of weakness by causing a transverse hot-cutting edge having a series of interruptions spaced along its length to move with and to perforate the web while it is moving to seal the layers of the web together at alongitudinally spaced intervals transversely to the fold, thereby leaving unsealed lands at interruptions between the perforations in the zone of weakness for holding adjacent bags together;
the web, as it moves, spanning slot-defining means moving in unison with the web; and the hot-cutting edge moving longitudinally at the same rate as the web and the slot-defining means, and also moving cyclically into the slot to intersect the web and then out of the slot.
displacing the web in a longitudinal direction along the direction of the fold;
cyclically providing longitudinally spaced transverse zones of weakness by causing a transverse hot-cutting edge having a series of interruptions spaced along its length to move with and to perforate the web while it is moving to seal the layers of the web together at alongitudinally spaced intervals transversely to the fold, thereby leaving unsealed lands at interruptions between the perforations in the zone of weakness for holding adjacent bags together;
the web, as it moves, spanning slot-defining means moving in unison with the web; and the hot-cutting edge moving longitudinally at the same rate as the web and the slot-defining means, and also moving cyclically into the slot to intersect the web and then out of the slot.
2. A method as claimed in Claim 1, in which the trans-verse hot-cutting edge moves cyclically to and fro with and against the direction of movement of the web, the movement of the hot-cutting edge into and out of the slot taking place after forward movement in the same direction as the web, and before return movement of the transverse hot-cutting edge in a direction against the movement of the web.
3. A method as claimed in Claim 1, in which the length of a perforation is between 10 and 150 times the length of an adjacent land.
4. A method as claimed in Claim 1, in which the thick-ness of the synthetic plastics film lies within the range of 5 microns and 100 microns.
5. A method as claimed in Claim 1, Claim 4, or Claim 4, in which the web is rolled into a roll at a region downstream from the perforating zone.
6. A continuous double layer web of synthetic plastics film made in accordance with the method claimed in Claim 1, and comprising a series of panels in the form of bags separated by a series of longitudinally spaced transverse zones of weakness extending across the width of the web, each zone of weakness comprising a series of heat-produced elongate perforations in the web separated by transversely spaced holding lands holding adjacent panels together, the two layers of film being sealed together along the lengths of the perforations, but being unsealed and separate at the holding lands between perforations.
7. A web as claimed in Claim 6, in which the perforation is from ten to one hundred and fifty times the length of a holding land.
8. A web as claimed in Claim 6, in which the film constituting the web has a thickness which lies within the range of 5 microns and 100 microns.
9. A web as claimed in Claim 6, in which at least one of the outermost lands is spaced inwardly from the edge of the web.
10. A web as claimed in any one of Claims 7 to 9 inclusive, in which the longitudinal edge of one layer projects transversely beyond the longitudinal edge of the other layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA76/4252 | 1976-07-16 | ||
| ZA00764252A ZA764252B (en) | 1976-07-16 | 1976-07-16 | Method and apparatus for processing synthetic plastics film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104783A true CA1104783A (en) | 1981-07-14 |
Family
ID=25570523
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA282,215A Expired CA1104783A (en) | 1976-07-16 | 1977-07-07 | Method and apparatus for processing synthetic plastics film |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5311974A (en) |
| AU (1) | AU512009B2 (en) |
| CA (1) | CA1104783A (en) |
| DE (1) | DE2732137C2 (en) |
| FR (1) | FR2358252A1 (en) |
| GB (2) | GB1578568A (en) |
| GR (1) | GR63747B (en) |
| NZ (1) | NZ184632A (en) |
| PT (1) | PT66818B (en) |
| ZA (1) | ZA764252B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU548255B2 (en) * | 1981-05-19 | 1985-12-05 | Aci Australia Limited | Flexible package |
| US4396449A (en) * | 1981-10-13 | 1983-08-02 | The Dow Chemical Company | Cutting and sealing process for thermoplastic materials |
| JPS60242025A (en) * | 1984-05-09 | 1985-12-02 | Mitsubishi Heavy Ind Ltd | Control of injection molding |
| CA1245236A (en) | 1984-09-26 | 1988-11-22 | Rene F. Debin | Bag stacking method and apparatus |
| US4767300A (en) * | 1987-11-02 | 1988-08-30 | Eastman Kodak Company | Apparatus for precision volumetric control of a moldable material in an injection molding process |
| US4913638A (en) * | 1988-06-20 | 1990-04-03 | Eastman Kodak Company | Apparatus for operating an injection molding process utilizing an acceptable part and process window |
| US5063008A (en) * | 1990-09-21 | 1991-11-05 | Eastman Kodak Company | Method for precision volumetric control of a moldable material in an injection molding process |
| US5238380A (en) * | 1990-09-21 | 1993-08-24 | Eastman Kodak Company | Apparatus for precision volumetric control of a moldable material |
| CN110202641B (en) * | 2019-06-23 | 2021-01-26 | 贵州西牛王印务有限公司 | Beer mounting test method for special agricultural and fine soil gift packaging box |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2525139A (en) * | 1946-03-04 | 1950-10-10 | Atlanta Paper Company | Pouch making machine |
| US3033257A (en) * | 1957-08-21 | 1962-05-08 | H G Weber And Company Inc | Bag forming tube and method of forming and accumulating the same |
| US3045891A (en) * | 1959-09-11 | 1962-07-24 | A Aba Cellophane Products Corp | Continuous envelopes |
| GB887292A (en) * | 1959-12-11 | 1962-01-17 | Metal Box Co Ltd | Improvements in or relating to sleeves made from synthetic thermoplastic film material |
| BE622541A (en) * | 1961-09-20 | 1900-01-01 | ||
| DE1182800B (en) * | 1961-10-04 | 1964-12-03 | Lehmacher & Sohn M | Device for cutting and / or welding thermoplastic hose or folded foils |
| US3194124A (en) * | 1961-11-17 | 1965-07-13 | Flex O Glass Inc | Method of forming tear-off bag supply |
| US3227854A (en) * | 1963-02-08 | 1966-01-04 | Reynolds Metals Co | Apparatus for perforating thermoplastic film |
| JPS4211513Y1 (en) * | 1965-02-22 | 1967-06-27 | ||
| FR2145055A5 (en) * | 1971-07-07 | 1973-02-16 | Membrino Hercules | Thermoplastic sacks or bags prodn |
-
1976
- 1976-07-16 ZA ZA00764252A patent/ZA764252B/en unknown
-
1977
- 1977-07-05 GB GB21555/79A patent/GB1578568A/en not_active Expired
- 1977-07-05 GB GB28118/77A patent/GB1578567A/en not_active Expired
- 1977-07-07 CA CA282,215A patent/CA1104783A/en not_active Expired
- 1977-07-12 GR GR53943A patent/GR63747B/en unknown
- 1977-07-12 NZ NZ18463277A patent/NZ184632A/en unknown
- 1977-07-13 FR FR7721811A patent/FR2358252A1/en active Granted
- 1977-07-13 AU AU26971/77A patent/AU512009B2/en not_active Expired
- 1977-07-14 JP JP8491077A patent/JPS5311974A/en active Pending
- 1977-07-15 DE DE2732137A patent/DE2732137C2/en not_active Expired
- 1977-07-15 PT PT6681877A patent/PT66818B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU512009B2 (en) | 1980-09-18 |
| FR2358252B1 (en) | 1983-10-14 |
| ZA764252B (en) | 1978-01-25 |
| GB1578567A (en) | 1980-11-05 |
| DE2732137C2 (en) | 1983-09-08 |
| FR2358252A1 (en) | 1978-02-10 |
| GB1578568A (en) | 1980-11-05 |
| PT66818B (en) | 1979-06-07 |
| DE2732137A1 (en) | 1978-01-26 |
| JPS5311974A (en) | 1978-02-02 |
| AU2697177A (en) | 1979-01-18 |
| GR63747B (en) | 1979-12-05 |
| PT66818A (en) | 1977-08-01 |
| NZ184632A (en) | 1980-11-14 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |