CA2084372A1 - Apparatus for producing transverse weld seams, transverse severing cuts and, respectively, transverse lines of perforations in tubular webs - Google Patents
Apparatus for producing transverse weld seams, transverse severing cuts and, respectively, transverse lines of perforations in tubular websInfo
- Publication number
- CA2084372A1 CA2084372A1 CA002084372A CA2084372A CA2084372A1 CA 2084372 A1 CA2084372 A1 CA 2084372A1 CA 002084372 A CA002084372 A CA 002084372A CA 2084372 A CA2084372 A CA 2084372A CA 2084372 A1 CA2084372 A1 CA 2084372A1
- Authority
- CA
- Canada
- Prior art keywords
- transverse
- web
- feed rolls
- pair
- cutting device
- 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.)
- Abandoned
Links
- 238000003466 welding Methods 0.000 claims abstract description 45
- 238000005520 cutting process Methods 0.000 claims abstract description 24
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 229920003002 synthetic resin Polymers 0.000 claims abstract description 4
- 239000000057 synthetic resin Substances 0.000 claims abstract description 4
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 4
- 239000004416 thermosoftening plastic Substances 0.000 claims abstract description 4
- 238000001514 detection method Methods 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/78—Means for handling the parts to be joined, e.g. for making containers or hollow articles, e.g. means for handling sheets, plates, web-like materials, tubular articles, hollow articles or elements to be joined therewith; Means for discharging the joined articles from the joining apparatus
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
- B29C66/431—Joining the articles to themselves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
- B29C66/431—Joining the articles to themselves
- B29C66/4312—Joining the articles to themselves for making flat seams in tubular or hollow articles, e.g. transversal seams
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/80—General aspects of machine operations or constructions and parts thereof
- B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
- B29C66/832—Reciprocating joining or pressing tools
- B29C66/8322—Joining or pressing tools reciprocating along one axis
- B29C66/83221—Joining or pressing tools reciprocating along one axis cooperating reciprocating tools, each tool reciprocating along one axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/90—Measuring or controlling the joining process
- B29C66/93—Measuring or controlling the joining process by measuring or controlling the speed
- B29C66/934—Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed
- B29C66/93451—Measuring or controlling the joining process by measuring or controlling the speed by controlling or regulating the speed by controlling or regulating the rotational speed, i.e. the speed of revolution
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2793/00—Shaping techniques involving a cutting or machining operation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2793/00—Shaping techniques involving a cutting or machining operation
- B29C2793/009—Shaping techniques involving a cutting or machining operation after shaping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/01—General aspects dealing with the joint area or with the area to be joined
- B29C66/05—Particular design of joint configurations
- B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
- B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
- B29C66/112—Single lapped joints
- B29C66/1122—Single lap to lap joints, i.e. overlap joints
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/90—Measuring or controlling the joining process
- B29C66/92—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools
- B29C66/924—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the pressure, the force, the mechanical power or the displacement of the joining tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/90—Measuring or controlling the joining process
- B29C66/94—Measuring or controlling the joining process by measuring or controlling the time
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/712—Containers; Packaging elements or accessories, Packages
- B29L2031/7128—Bags, sacks, sachets
-
- 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
- B31B70/006—Controlling; Regulating; Measuring; Safety measures
-
- 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
- B31B70/60—Uniting opposed surfaces or edges; Taping
- B31B70/64—Uniting opposed surfaces or edges; Taping by applying heat or pressure
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Making Paper Articles (AREA)
Abstract
AN APPARATUS FOR PRODUCING TRANSVERSE WELD
SEAMS, TRANSVERSE SEVERING CUTS AND, RESPECTIVELY, TRANSVERSE LINES OF PERFORATIONS IN TUBULAR WEBS
ABSTRACT
The present invention relates to an apparatus for producing transverse weld seams and transverse severing cuts or transverse lines of perforations in a tubular or semi-tubular web of thermoplastic synthetic resin which is intermittently pushed and/or drawn forwards, comprising two cooperating pairs of feed rolls separated by a transverse welding device, and a cutting or perforating device. In order to attain the object of increasing production capacity of such equipment while still maintaining weld quality, the transverse welding device arranged between the two pairs of feed rolls comprises at least two pairs of welding jaws with a transverse alignment in relation to the web, which are spaced apart by at least the length of a bag or other workpiece as measured in the direction of movement of the web.
SEAMS, TRANSVERSE SEVERING CUTS AND, RESPECTIVELY, TRANSVERSE LINES OF PERFORATIONS IN TUBULAR WEBS
ABSTRACT
The present invention relates to an apparatus for producing transverse weld seams and transverse severing cuts or transverse lines of perforations in a tubular or semi-tubular web of thermoplastic synthetic resin which is intermittently pushed and/or drawn forwards, comprising two cooperating pairs of feed rolls separated by a transverse welding device, and a cutting or perforating device. In order to attain the object of increasing production capacity of such equipment while still maintaining weld quality, the transverse welding device arranged between the two pairs of feed rolls comprises at least two pairs of welding jaws with a transverse alignment in relation to the web, which are spaced apart by at least the length of a bag or other workpiece as measured in the direction of movement of the web.
Description
1090-18 ;~ , J~ s) AN APP~ATUS FOR PRODUCING TRANS~IERSE WELD
SEAMS, TRANSVERSE SEVERING CUTS ~ND, RESPECTIVELY, TR~NSVERSE LINES OF PERFOR~TIONS IN TUBULAR WEBS
The present invention relates to an apparatus for producing transverse weld seams and transverse severing cuts, or transverse llnes of perforations, in a tubular or semi-tubular web of thermoplastic synthetic resin which is intermittently pushed and/or drawn forwards, comprising cooperating pairs of feed rolls, a transverse welding device and a cutting or, alternatively, a perforating device.
An apparatus of -this type is known in which a suitable flattened semi-tubular web is advanced intermittently by the length of one bag at a time and is welded transversely in a transverse welding device by means of a pair of welding jaws adapted to be moved together. As a rule a corresponding cutting or perforating knife is arranged directly following the transverse welding device and extends transversely in relation to the web with the result that simultaneously with the production of the transverse weld seam for instance, the bottom weld, the corresponding severing cut, or line of perforations is produced. In such equipment the stroke rate, and consequently the speed of production of the bags, or other workpieces, is limited by the welding time. If the speed Of production of such equipment is to be increased by a suitably higher frequency or rate, there is the danger of there not being sufficient time for the welding of the web, so that the quality of the welded seams is no longer in accordance with the set requirements.
Thus the invention seeks to improve on an apparatus of this type, so that while having a comparatively high rate of production, there is nevertheless sufficient time for the welding operation and the bags, or workpieces, are produced with satisfactory quality weld seams.
In accordance with the invention the transverse welding device includes a first and a second pair of feed rolls having located in between them at least two pairs of welding jaws with a transverse alignment in relation to the web. These welding jaws are spaced apart by at least the length of one bag as measured in the direction of movement of the tubular web. This transverse welding device is followed by a cutting device comprising a single cutting or perforating knife extending transversely in relation to the web. In accordance with the invention, for a single operational stroke a relatively long piece of the web is advanced into the transverse welding device, where, by means of pairs of welding jaws spaced from each other by the length of one bag, a plurality of transverse weld seams are produced simultaneously. After welding, the piece of web is moved out of the transverse welding device and is cut off by the transverse cutting or perforating knife. The knife then cuts or perforates at double, treble, quadruple, etcetera, the stroke rate of the welding device, depending on the number of transverse welds formed simultaneously. This design uses the fact that the time for cutting the web is comparatively much less than the time necessary for welding.
By means of this design it is possible to more than double the speed of production as compared to conventional equipment. It is at the same time possible to ensure that there is a sufficiently long welding time for the production of the transverse weld seams.
The sections of bag cut or perforated in this manner may be impaled, stacked etcetera, or may be rolled up on a new roll.
In accordance with a further embodiment, the cutting or perforating knife is preceded by a third pair of feed rolls. Furthermore, there is a moveable dandy roll arranged between the second pair of feed rolls following the transverse welding jaws, and the third pair of feed rolls.
C ~
The web is passed over-the dandy roll leading to a manner of operation which ls more particularly advantageous if the bags are to be stacked, since the welding times may be adhered to continuously and without interruption or delay.
In this case after stacking a number of bags, which are to be remoyed by a suitable conveyor, the knife is held stationary. However, the web is advanced at a constant speed from the welding device. Simultaneously, the dandy roll is moved to lengthen the path to the knife with the result that the transversely welded web is diverted until, after suitable removal of the stack of bags, the cutting knife resumes action. Then the stroke rate during cutting is increased to be greater than that of the continuous welding stroke rate, so that the temporarily stored length of the welded web around the deflected dandy roll is processed before the next time the knife is halted.
Within the range of movement of the dandy roll it is possible to set two photoelectric cells which function to detect a critical deflection of the dandy roll. As an alternative to this, it is possible for a detector fork to be arranged adjacent to the driving means for the dandy roll. The fork functions to detect a critical deflection of the dandy roll using a suitable microswitch. Such arrangements providing signals for the detection of the critical or limiting deflection of the dandy roll render possible a further preferred manner of operation of the apparatus. In accordance with these working embodiments the increase in the cutting stroke rate may be predetermined by the control so as to be practically constant. When the dandy roll reaches one of its critical positions, a corresponding signal is passed to the stroke rate controller for the knife with the result that the frequency of cutting is correspondingly increased, or diminished.
In keeping with yet another advantageous embodiment of the invention, the pairs of feed rolls and the cutting or perforating knife or knives are preferably driven using servo-motors. In this respect a main control device may be provided for the control oE the machine generally, and a further control device may be provided for the third pair of feed rolls and the cutting, or perforating, knife. In accordance with one possible design, no severing cuts are made and instead the tubular web is transversely perforated close to the transverse weld seams.
In this case there is a presser roll following the perforating knife, in terms of the direction of movement of the web, which is able to be driven by a servo-motor and is in cooperation with a means for winding up the web. Such a presser roll is to be controlled using a further control means.
Further advantageous developments and convenient forms of the invention will be gathered from the following detailed account of some embodiments thereof in conjunction with the accompanying drawings.
Figure 1 shows a first working embodiment of the apparatus in accordance with the invention, in which the bags are cut, and then impaled.
Figure 2 shows a second working embodiment of the present invention, in which the tubular web is cut and the cut bags are -then stacked.
Figure 3 is a view of a third working embodiment of the present invention, in which the tubular web is provided with transverse perforations and weld seams, and in which the web is then wound up again on a new roll.
Figure 4 illustrates a working embodiment, which is essentially the same as that of Figure 3, but in which the cut bags are not stacked but continuously moved into a filling device.
In the embodiment in accordance with Figure 1 the welding device shown within the broken lines includes the first and second pairs of feed rolls 12 and 14, and the pairs of welding jaws 16, and 18, which extend transversely in relation to the tubular web 10 between the roll pairs 12 and 14., The pairs 16 and 18 of welding jaws are spaced apart in relation to each other by one bag length (or the length of one workpiece) and are arranged parallel to each other. In Figure 1 reference numeral 32 denotes the servo-motor driving the pair of feed rolls 19. In a like manner the pair of feed rolls 12, and also the corresponding pairs of welding jaws 16 and 18, are driven by servo-motors, not illustrated. All the servo-motors are driven via the main control device 38 by means of which more particularly the stroke rate 40 and furthermore the length of the bags (or workpieces) are set. In the apparatus described here the tubular web 10 is therefore fed in accordance with the steady stroke rate as set by the main control device 38 and during one time interval the web is simultaneously welded by means of the pairs 16 and 18 of welding jaws.
This welding device is followed by a third pair of feed rolls 20, which is arranged directly preceding a knife 24. The pair of feed rolls 20 is driven intermittently via a servo-motor 39. The knife 29 arranged following the pair of feed rolls 20 in terms of the direction of web travel is also driven using a servo-motor. The knife 24 cuts the tubular web shortly before or after the respective transverse weld seams with a frequency or rate approximately double that of the frequency of the feed of the tubular web in the transverse welding device. The resulting bag sections are impaled on a pin rail 26 following the knife 24, the drive for the pin rail 26 being referenced 48 in Figure 1. There are grippers 30 driven by a drive 35 in order to engage and remove the bags when the stack has reached a predetermined height.
? ~3 setween the pair of feed rolls 14 and the pair of feed rolls 20, a dandy roll 22 is arranged, over which the tubular web 10, which has already been transversely welded, is trained. Furthermore, two photoelectric cells 52 and 54 are arranged in the apparatus, by which corresponding critical,or excessive deflections of the dandy roll 22 may be detected.
The apparatus in accordance with this working embodiment possesses a controller 42 which functions to correspondingly control the pair 20 of feed rolls via the servo-motor 34 and of the knife 24 via the further servo-motor, not illustrated. The control device is firstly supplied with the stroke frequency 40 of the main controller 38. Furthermore a signal corresponding to the feed of the pair 14 of feed rolls is supplied via a pulse generator 46 of the servo-motor 32 to the controller 42. Simultaneously the controller 42 receives a signal from the pulse generator 94 of the servo-motor 34, which drives the pair of feed rolls 20. The controller 42 recelves further signals from the drive of the pin rail 48 and the gripper drive 35 and from a counter 50 associated with the knife 24. In accordance with these signals it is now possible for the controller to control the servo-motor 34 of the pair of fed rolls 20 and, if present, the servo-motor of the knife 24.
Lastly further signals from the photoelectric cells 52 and 54 may be supplied to the controller.
The manner of operation of the working embodiment of the invention described here is as follows. First, the feed stroke rate or frequency of the transverse welding device is predetermined at a constant value by the main control device 38. The pairs 16 and 18 of welding jaws are set in the transverse welding device in accordance with the desired length of bag. The feed stroke frequency or rate 40 is passed on to the controller 42. Simultaneously the feed signal of the pair 14 of feed rolls is passed on via the pulse generator 46 of the controller 42. The tubular web 10 is advanced to the pair of feed rolls 20 and cut by the knife 24. After this, the bag sections are lmpaled until a predetermined number of bags ls reached, for instance 100 bags. The number of bags is counted by the counter 50.
When the.desired number of bags in the stack is reached, a corresponding signal is sent by the counter 50 to the gripper drive 35, the pin rail drive 48, and to the controller 42. Now the pin rail 26 is retracted from the stack so that the stack may be removed by the gripper 30.
Then, further signals are sent from the gripper drive 35 and the pin rail drive 48 to the controller 42. During the time in which the gripper drive 35 and the pin rail drive 48 are in operation, it is necessary for at least the pair of feed rolls 20 to be halted. Preferably, the knife 24 should also be stopped. Ilowever, it may be run continuously without halting. The tubular web 10 emerging from the transverse welding device, during the time the stack is being moved, continues to run at the same speed over a dandy roll 22 in an increasing loop, as shown in Figure 1. After removal of the stack of bags the controller 42 causes the pair of feed rolls 20 to start with a predetermined speed of rotation.
In this case the stroke rate is set to be somewhat greater than twice the stroke rate at which the tubular web 10 is advanced into the transverse welding device. As a result the loop formed around the dandy roll 22 is shortened. In this respect the increase in the stroke rate of the pair of feed rolls 20 is selected so that the temporarily stored or held length of the tubular web 10 is used up again by the time the next removal of a stack of bags occurs. If, however, the stroke rate or frequency selected is too high, the movement of the dandy roll 22 beyond a set limit is detected by the photoelectric cell 52 with the result that a corresponding signal is sent to the controller 42. Then the stroke rate is decreased by an appropriate amount so that the loop in the tubular web 10 is increased in ensuing operation. The same applies for detection by the lower r ? ' ~
photoelectric cell 54 of a stroke rate which is too low causing the dandy roll 22 to travel beyond the set lower limit.
The working embodiment in accordance with Figure
SEAMS, TRANSVERSE SEVERING CUTS ~ND, RESPECTIVELY, TR~NSVERSE LINES OF PERFOR~TIONS IN TUBULAR WEBS
The present invention relates to an apparatus for producing transverse weld seams and transverse severing cuts, or transverse llnes of perforations, in a tubular or semi-tubular web of thermoplastic synthetic resin which is intermittently pushed and/or drawn forwards, comprising cooperating pairs of feed rolls, a transverse welding device and a cutting or, alternatively, a perforating device.
An apparatus of -this type is known in which a suitable flattened semi-tubular web is advanced intermittently by the length of one bag at a time and is welded transversely in a transverse welding device by means of a pair of welding jaws adapted to be moved together. As a rule a corresponding cutting or perforating knife is arranged directly following the transverse welding device and extends transversely in relation to the web with the result that simultaneously with the production of the transverse weld seam for instance, the bottom weld, the corresponding severing cut, or line of perforations is produced. In such equipment the stroke rate, and consequently the speed of production of the bags, or other workpieces, is limited by the welding time. If the speed Of production of such equipment is to be increased by a suitably higher frequency or rate, there is the danger of there not being sufficient time for the welding of the web, so that the quality of the welded seams is no longer in accordance with the set requirements.
Thus the invention seeks to improve on an apparatus of this type, so that while having a comparatively high rate of production, there is nevertheless sufficient time for the welding operation and the bags, or workpieces, are produced with satisfactory quality weld seams.
In accordance with the invention the transverse welding device includes a first and a second pair of feed rolls having located in between them at least two pairs of welding jaws with a transverse alignment in relation to the web. These welding jaws are spaced apart by at least the length of one bag as measured in the direction of movement of the tubular web. This transverse welding device is followed by a cutting device comprising a single cutting or perforating knife extending transversely in relation to the web. In accordance with the invention, for a single operational stroke a relatively long piece of the web is advanced into the transverse welding device, where, by means of pairs of welding jaws spaced from each other by the length of one bag, a plurality of transverse weld seams are produced simultaneously. After welding, the piece of web is moved out of the transverse welding device and is cut off by the transverse cutting or perforating knife. The knife then cuts or perforates at double, treble, quadruple, etcetera, the stroke rate of the welding device, depending on the number of transverse welds formed simultaneously. This design uses the fact that the time for cutting the web is comparatively much less than the time necessary for welding.
By means of this design it is possible to more than double the speed of production as compared to conventional equipment. It is at the same time possible to ensure that there is a sufficiently long welding time for the production of the transverse weld seams.
The sections of bag cut or perforated in this manner may be impaled, stacked etcetera, or may be rolled up on a new roll.
In accordance with a further embodiment, the cutting or perforating knife is preceded by a third pair of feed rolls. Furthermore, there is a moveable dandy roll arranged between the second pair of feed rolls following the transverse welding jaws, and the third pair of feed rolls.
C ~
The web is passed over-the dandy roll leading to a manner of operation which ls more particularly advantageous if the bags are to be stacked, since the welding times may be adhered to continuously and without interruption or delay.
In this case after stacking a number of bags, which are to be remoyed by a suitable conveyor, the knife is held stationary. However, the web is advanced at a constant speed from the welding device. Simultaneously, the dandy roll is moved to lengthen the path to the knife with the result that the transversely welded web is diverted until, after suitable removal of the stack of bags, the cutting knife resumes action. Then the stroke rate during cutting is increased to be greater than that of the continuous welding stroke rate, so that the temporarily stored length of the welded web around the deflected dandy roll is processed before the next time the knife is halted.
Within the range of movement of the dandy roll it is possible to set two photoelectric cells which function to detect a critical deflection of the dandy roll. As an alternative to this, it is possible for a detector fork to be arranged adjacent to the driving means for the dandy roll. The fork functions to detect a critical deflection of the dandy roll using a suitable microswitch. Such arrangements providing signals for the detection of the critical or limiting deflection of the dandy roll render possible a further preferred manner of operation of the apparatus. In accordance with these working embodiments the increase in the cutting stroke rate may be predetermined by the control so as to be practically constant. When the dandy roll reaches one of its critical positions, a corresponding signal is passed to the stroke rate controller for the knife with the result that the frequency of cutting is correspondingly increased, or diminished.
In keeping with yet another advantageous embodiment of the invention, the pairs of feed rolls and the cutting or perforating knife or knives are preferably driven using servo-motors. In this respect a main control device may be provided for the control oE the machine generally, and a further control device may be provided for the third pair of feed rolls and the cutting, or perforating, knife. In accordance with one possible design, no severing cuts are made and instead the tubular web is transversely perforated close to the transverse weld seams.
In this case there is a presser roll following the perforating knife, in terms of the direction of movement of the web, which is able to be driven by a servo-motor and is in cooperation with a means for winding up the web. Such a presser roll is to be controlled using a further control means.
Further advantageous developments and convenient forms of the invention will be gathered from the following detailed account of some embodiments thereof in conjunction with the accompanying drawings.
Figure 1 shows a first working embodiment of the apparatus in accordance with the invention, in which the bags are cut, and then impaled.
Figure 2 shows a second working embodiment of the present invention, in which the tubular web is cut and the cut bags are -then stacked.
Figure 3 is a view of a third working embodiment of the present invention, in which the tubular web is provided with transverse perforations and weld seams, and in which the web is then wound up again on a new roll.
Figure 4 illustrates a working embodiment, which is essentially the same as that of Figure 3, but in which the cut bags are not stacked but continuously moved into a filling device.
In the embodiment in accordance with Figure 1 the welding device shown within the broken lines includes the first and second pairs of feed rolls 12 and 14, and the pairs of welding jaws 16, and 18, which extend transversely in relation to the tubular web 10 between the roll pairs 12 and 14., The pairs 16 and 18 of welding jaws are spaced apart in relation to each other by one bag length (or the length of one workpiece) and are arranged parallel to each other. In Figure 1 reference numeral 32 denotes the servo-motor driving the pair of feed rolls 19. In a like manner the pair of feed rolls 12, and also the corresponding pairs of welding jaws 16 and 18, are driven by servo-motors, not illustrated. All the servo-motors are driven via the main control device 38 by means of which more particularly the stroke rate 40 and furthermore the length of the bags (or workpieces) are set. In the apparatus described here the tubular web 10 is therefore fed in accordance with the steady stroke rate as set by the main control device 38 and during one time interval the web is simultaneously welded by means of the pairs 16 and 18 of welding jaws.
This welding device is followed by a third pair of feed rolls 20, which is arranged directly preceding a knife 24. The pair of feed rolls 20 is driven intermittently via a servo-motor 39. The knife 29 arranged following the pair of feed rolls 20 in terms of the direction of web travel is also driven using a servo-motor. The knife 24 cuts the tubular web shortly before or after the respective transverse weld seams with a frequency or rate approximately double that of the frequency of the feed of the tubular web in the transverse welding device. The resulting bag sections are impaled on a pin rail 26 following the knife 24, the drive for the pin rail 26 being referenced 48 in Figure 1. There are grippers 30 driven by a drive 35 in order to engage and remove the bags when the stack has reached a predetermined height.
? ~3 setween the pair of feed rolls 14 and the pair of feed rolls 20, a dandy roll 22 is arranged, over which the tubular web 10, which has already been transversely welded, is trained. Furthermore, two photoelectric cells 52 and 54 are arranged in the apparatus, by which corresponding critical,or excessive deflections of the dandy roll 22 may be detected.
The apparatus in accordance with this working embodiment possesses a controller 42 which functions to correspondingly control the pair 20 of feed rolls via the servo-motor 34 and of the knife 24 via the further servo-motor, not illustrated. The control device is firstly supplied with the stroke frequency 40 of the main controller 38. Furthermore a signal corresponding to the feed of the pair 14 of feed rolls is supplied via a pulse generator 46 of the servo-motor 32 to the controller 42. Simultaneously the controller 42 receives a signal from the pulse generator 94 of the servo-motor 34, which drives the pair of feed rolls 20. The controller 42 recelves further signals from the drive of the pin rail 48 and the gripper drive 35 and from a counter 50 associated with the knife 24. In accordance with these signals it is now possible for the controller to control the servo-motor 34 of the pair of fed rolls 20 and, if present, the servo-motor of the knife 24.
Lastly further signals from the photoelectric cells 52 and 54 may be supplied to the controller.
The manner of operation of the working embodiment of the invention described here is as follows. First, the feed stroke rate or frequency of the transverse welding device is predetermined at a constant value by the main control device 38. The pairs 16 and 18 of welding jaws are set in the transverse welding device in accordance with the desired length of bag. The feed stroke frequency or rate 40 is passed on to the controller 42. Simultaneously the feed signal of the pair 14 of feed rolls is passed on via the pulse generator 46 of the controller 42. The tubular web 10 is advanced to the pair of feed rolls 20 and cut by the knife 24. After this, the bag sections are lmpaled until a predetermined number of bags ls reached, for instance 100 bags. The number of bags is counted by the counter 50.
When the.desired number of bags in the stack is reached, a corresponding signal is sent by the counter 50 to the gripper drive 35, the pin rail drive 48, and to the controller 42. Now the pin rail 26 is retracted from the stack so that the stack may be removed by the gripper 30.
Then, further signals are sent from the gripper drive 35 and the pin rail drive 48 to the controller 42. During the time in which the gripper drive 35 and the pin rail drive 48 are in operation, it is necessary for at least the pair of feed rolls 20 to be halted. Preferably, the knife 24 should also be stopped. Ilowever, it may be run continuously without halting. The tubular web 10 emerging from the transverse welding device, during the time the stack is being moved, continues to run at the same speed over a dandy roll 22 in an increasing loop, as shown in Figure 1. After removal of the stack of bags the controller 42 causes the pair of feed rolls 20 to start with a predetermined speed of rotation.
In this case the stroke rate is set to be somewhat greater than twice the stroke rate at which the tubular web 10 is advanced into the transverse welding device. As a result the loop formed around the dandy roll 22 is shortened. In this respect the increase in the stroke rate of the pair of feed rolls 20 is selected so that the temporarily stored or held length of the tubular web 10 is used up again by the time the next removal of a stack of bags occurs. If, however, the stroke rate or frequency selected is too high, the movement of the dandy roll 22 beyond a set limit is detected by the photoelectric cell 52 with the result that a corresponding signal is sent to the controller 42. Then the stroke rate is decreased by an appropriate amount so that the loop in the tubular web 10 is increased in ensuing operation. The same applies for detection by the lower r ? ' ~
photoelectric cell 54 of a stroke rate which is too low causing the dandy roll 22 to travel beyond the set lower limit.
The working embodiment in accordance with Figure
2 operates basically in a similar manner to that of Figure 1, so like parts of the apparatus with the same functions are denoted by like reference numerals. In-the case of this working embodiment the welding device has, in addition to the pairs 12 and 14 of feed rolls, which intermittently advance the tubular web 10, a further pair of feed rolls 11 placed preceding the pair of feed rolls 12 in terms of the direction of movement of the web which continuously feeds the web 10. In order to allow for differences between this continuous feed and the lntermittent feed of the pairs of feed rolls 12 and 14, there is an additional dandy roll 13 about which the tubular web 10 is trained. In the working embodiment the pair of feed rolls 20 is continuously driven.
In this working embodiment the counter is in the form of a photoelectric cell 66 arranged over the web 10 which can also detect dents or pressure marks on the tubular web 10, and feed a signal to the controller 42. The knife 31 is, in this case, a rotary one, which is driven by a servo-motor 36. The motor 36 is controlled by the pulse generator 37 which also sends pulses to the controller 42.
In this respect it is advantageous if the knife is run at a slightly higher speed than the actual stroke rate set, since such corresponding lead is responsible for an improved cut.
The rotary knife 31 is followed in terms of the direction of movement of the web 10 by a conveyor belt 66' for grasping and removing the cut bags. The conveyor belt 66' conveys the bags into a suitable container or cassette 68 in which the bags are stacked until the desired stack height has been reached. When the predetermined stack height has been reached, a corresponding pneumatic piston and cylinder unit J " ~ J ~, ~
72 retracts the bo~tom of the container 70 with the result that the stacks are deposited on a cassette belt 74, which functions to remove the stacks of bags.
To distinguish this from the working embodiment in accordan~e with Figure 1, the critical or excessive deflections of the dandy roll 22 in this case are not detected by photoelectric cells but rather by a detector fork 60. A suitable electrical contact or microswitch is utilized to provide an upper and a lower limit signal. The signal is passed via the potentiometer 62 to the frequency converter 64 and directly to the servo-motor 34, which drives the pair of feed rolls 20. A corresponding signal goes from the pulse generator 44, arranged on the output side of the servo-motor 34, to the controller 42, which controls the speed of rotation of the rotary knife via the servo-motor.
The working embodiment in accordance with Figure
In this working embodiment the counter is in the form of a photoelectric cell 66 arranged over the web 10 which can also detect dents or pressure marks on the tubular web 10, and feed a signal to the controller 42. The knife 31 is, in this case, a rotary one, which is driven by a servo-motor 36. The motor 36 is controlled by the pulse generator 37 which also sends pulses to the controller 42.
In this respect it is advantageous if the knife is run at a slightly higher speed than the actual stroke rate set, since such corresponding lead is responsible for an improved cut.
The rotary knife 31 is followed in terms of the direction of movement of the web 10 by a conveyor belt 66' for grasping and removing the cut bags. The conveyor belt 66' conveys the bags into a suitable container or cassette 68 in which the bags are stacked until the desired stack height has been reached. When the predetermined stack height has been reached, a corresponding pneumatic piston and cylinder unit J " ~ J ~, ~
72 retracts the bo~tom of the container 70 with the result that the stacks are deposited on a cassette belt 74, which functions to remove the stacks of bags.
To distinguish this from the working embodiment in accordan~e with Figure 1, the critical or excessive deflections of the dandy roll 22 in this case are not detected by photoelectric cells but rather by a detector fork 60. A suitable electrical contact or microswitch is utilized to provide an upper and a lower limit signal. The signal is passed via the potentiometer 62 to the frequency converter 64 and directly to the servo-motor 34, which drives the pair of feed rolls 20. A corresponding signal goes from the pulse generator 44, arranged on the output side of the servo-motor 34, to the controller 42, which controls the speed of rotation of the rotary knife via the servo-motor.
The working embodiment in accordance with Figure
3 is similar to that of Figure 2. A basic difference between it and the working embodiment in accordance with Figure 2 is that in this case no individual bag sections are cut from the tubular web, and instead the tubular web is transversely perforated at the weld seams by a rotary perforating knife 31. Therefore the entire tubular web 10, with the addition of weld seams and the transverse perforations, is wound up on the rewinding device 86. Owing to this the apparatus in accordance with Figure 3 differs from the apparatus as shown in Figure 2 essentially in that a presser roll 84 is provided, which functions to wind up the tubular web again in a satisfactory manner. The presser roll 84 is driven via a controller 76 and a servo-motor 82 controlled thereby. In the controller 76 a signal produced by the detector fork 60 in response to the position of the dandy roll 22 is sent via the potentiometer 62 and the frequency converter 64. Here a signal corresponding to the deflection of the dandy roll 22 is utilized as a guide r,1 '~
value. A further dandy roll 80 following the rotary perforating knife 31 forms an additional loop of the tubular web 10. The loop runs around the dandy roll 80 between two rolls 78. The deflection of this dandy roll 80 is converted into a signal which goes via a potentiometer 77 as a correction signal to the controller 76.
The working embodiment in accordance with Figure
value. A further dandy roll 80 following the rotary perforating knife 31 forms an additional loop of the tubular web 10. The loop runs around the dandy roll 80 between two rolls 78. The deflection of this dandy roll 80 is converted into a signal which goes via a potentiometer 77 as a correction signal to the controller 76.
The working embodiment in accordance with Figure
4 is the same in all details as the working embodiment as shown in Figure 2. There is one difference only as regards the fact that the bag sections cut by the rotary knife 31 and moved forwards by the conveyor belt 66' are run directly into a filling machine 67, where the bag sections are filled and then sealed.
Claims (14)
1. An apparatus for producing transverse weld seams and transverse cuts in a tubular or semi-tubular web of thermoplastic synthetic resin, through which the web is intermittently advanced, comprising a transverse welding device including:
a first pair of feed rolls;
at least two pairs of transverse welding jaws, each pair adjustably arranged laterally in the direction of web travel with at least the length of one workpiece between them; and a second pair of feed rolls; and a transverse cutting device following the welding device in the direction of web travel.
a first pair of feed rolls;
at least two pairs of transverse welding jaws, each pair adjustably arranged laterally in the direction of web travel with at least the length of one workpiece between them; and a second pair of feed rolls; and a transverse cutting device following the welding device in the direction of web travel.
2. The apparatus as claimed in Claim 1 wherein a moveable dandy roll and a following third pair of feed rolls are provided between the second pair of feed rolls and the cutting device.
3. The apparatus as claimed in Claim 1 or 2 wherein the cutting device comprises a transverse knife having an independently controllable stroke rate for severing bag sections from the web.
4. The apparatus as claimed in Claim 2, wherein two photoelectric cells are arranged in the path of movement of the dandy roll to detect deflection of the dandy roll.
5. The apparatus as claimed in Claim 2, wherein a detector fork is arranged within the range of movement of the mechanism of the dandy roll for the detection of deflection of the dandy roll.
6. The apparatus as claimed in Claim 1 or 2, wherein the pairs of feed rolls, the pairs of welding jaws, and the cutting device, are adapted to be driven by independently controlled servo-motors.
7. The apparatus as claimed in Claim 2 further including a main control device for the control of the overall machine and a subsidiary control device for the control of the pair of third feed rolls and for the control of the cutting device.
8. The apparatus as claimed in Claim 1 wherein the transverse cutting device comprises a rotating perforating knife providing a transverse row of separated cuts.
9. The apparatus as claimed in Claim 8 wherein a presser roll is included following the perforating knife which is adapted to be driven by a servo-motor and to cooperate with a winding up device, such presser roll being adapted to be driven by means of a further controller.
10. The apparatus as claimed in Claim 2 wherein the transverse cutting device comprises a rotating perforating knife providing a transverse row of separated cuts.
11. The apparatus as claimed in Claim 10 wherein a presser roll is included following the perforating knife which is adapted to be driven by a servo-motor and to cooperate with a winding up device, such presser roll being adapted to be driven by means of a further controller.
12. A method for producing transverse weld seams and transverse cuts in a tubular or semi-tubular web of thermoplastic synthetic resin comprising:
intermittently advancing a web through a transverse welding device;
forming simultaneously at least two transverse welds on the web in the welding device, the transverse welds being separated by at least the length of one workpiece section;
advancing the web provided with transverse welds to a transverse cutting device; and operating the transverse cutting device at a rate significantly faster than the welding operation to provide transverse lines of perforation or transverse severing cuts.
intermittently advancing a web through a transverse welding device;
forming simultaneously at least two transverse welds on the web in the welding device, the transverse welds being separated by at least the length of one workpiece section;
advancing the web provided with transverse welds to a transverse cutting device; and operating the transverse cutting device at a rate significantly faster than the welding operation to provide transverse lines of perforation or transverse severing cuts.
13. The method as claimed in Claim 12 wherein the intermittent advancement of the web is diverted by a dandy roll to permit interruption of the cutting device.
14. The method as claimed in Claim 12 wherein the workpiece comprises a bag.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4139698.7 | 1991-12-02 | ||
| DE19914139698 DE4139698A1 (en) | 1991-12-02 | 1991-12-02 | DEVICE FOR ATTACHING CROSS-WELDING SEAMS AND CROSS-SEPARATING CUTS OR CROSS-PERFORMANCE LINES ON TUBE Lanes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2084372A1 true CA2084372A1 (en) | 1993-06-03 |
Family
ID=6446085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002084372A Abandoned CA2084372A1 (en) | 1991-12-02 | 1992-12-02 | Apparatus for producing transverse weld seams, transverse severing cuts and, respectively, transverse lines of perforations in tubular webs |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0545057A1 (en) |
| JP (1) | JPH05278152A (en) |
| CA (1) | CA2084372A1 (en) |
| DE (1) | DE4139698A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003055669A1 (en) * | 2001-12-26 | 2003-07-10 | Nishibe Kikai Co., Ltd. | Bag-making machine |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5447486A (en) * | 1992-11-25 | 1995-09-05 | Fmc Corporation | Maintaining perforation phasing |
| US5292299A (en) * | 1992-11-25 | 1994-03-08 | Fmc Corporation | Maintaining perforation phasing |
| EP0844070A1 (en) * | 1996-11-26 | 1998-05-27 | Kraft Foods, Inc. | Method and apparatus for obtaining individual web sections |
| US5800325A (en) * | 1997-03-26 | 1998-09-01 | Wilkes; Kenneth R. | High speed machine and method for fabricating pouches |
| DE102007010994B4 (en) * | 2007-03-05 | 2009-04-02 | Julius Dr.-Ing. Schröder-Frerkes | Method and device for applying sections of strip material to moving blanks |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1809659A1 (en) * | 1968-11-19 | 1970-07-30 | Hoeller Gmbh Geb | Apparatus for manufacturing packaging bags |
| US4030956A (en) * | 1972-03-15 | 1977-06-21 | Wavin B.V. | Method of manufacturing plastic bags in a continuous way |
| DE3202337C2 (en) * | 1982-01-26 | 1984-06-28 | Windmöller & Hölscher, 4540 Lengerich | Device for the production of handle bags with increased production speed |
| EP0297434B1 (en) * | 1987-06-29 | 1992-02-19 | WindmÀ¶ller & Hölscher | Method of controlling bag or sack production machines |
| US5009740A (en) * | 1989-08-09 | 1991-04-23 | Nippon Flute Co., Ltd. | Bag making machine |
-
1991
- 1991-12-02 DE DE19914139698 patent/DE4139698A1/en not_active Withdrawn
-
1992
- 1992-10-22 EP EP19920118095 patent/EP0545057A1/en not_active Withdrawn
- 1992-12-02 CA CA002084372A patent/CA2084372A1/en not_active Abandoned
- 1992-12-02 JP JP32318492A patent/JPH05278152A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003055669A1 (en) * | 2001-12-26 | 2003-07-10 | Nishibe Kikai Co., Ltd. | Bag-making machine |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05278152A (en) | 1993-10-26 |
| DE4139698A1 (en) | 1993-06-03 |
| EP0545057A1 (en) | 1993-06-09 |
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