CA1245499A - Apparatus for making quadruple profile plastic tubing for bags - Google Patents
Apparatus for making quadruple profile plastic tubing for bagsInfo
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- CA1245499A CA1245499A CA000544001A CA544001A CA1245499A CA 1245499 A CA1245499 A CA 1245499A CA 000544001 A CA000544001 A CA 000544001A CA 544001 A CA544001 A CA 544001A CA 1245499 A CA1245499 A CA 1245499A
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Abstract
ABSTRACT
Apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the confronting top edges, comprises an extruder for extruding a continuous tube with pairs of closely spaced interlocking elements on the surface of the tube, the total pairs being a multiple of 2 with at least 4 pairs on the tube, a slitter for slitting the tube lengthwise between profiles of alternate pairs, and a folder for folding the tube between each adjacent pair and for bringing the profile adjacent the slit over onto the closest profile of the pair which has not been slit.
Apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the confronting top edges, comprises an extruder for extruding a continuous tube with pairs of closely spaced interlocking elements on the surface of the tube, the total pairs being a multiple of 2 with at least 4 pairs on the tube, a slitter for slitting the tube lengthwise between profiles of alternate pairs, and a folder for folding the tube between each adjacent pair and for bringing the profile adjacent the slit over onto the closest profile of the pair which has not been slit.
Description
4~9 S P E C I F I C A T I O N
The invention relates to improvements in apparatus for making plastic film bags having reclos-able fasteners thereon, and particularly of the type 5 having opposed in~erlocking rib and groove elements on the confronting top edges of the bags.
In the manufacture of bags of this type, continual efforts are being made to increase the speed of production output to thereby effect a saving in cost of the individual bags. There are factors which limit 10 the speed cf extrusion of the film and speed of joining of profiles so that the present concept embodies manu-facturing simultaneously a plurality of bags in a unique manner so that actually, material for making four bags with each cross-sealing operation is produced 15 simultaneously in a single tubular extrusion film.
Attempts to make multiple bags in a single extrusion operation encounter the problems of control-ling the film and controlling the profiles. The pro-files are joined before the film is wound or spooled in 20 order to avoid the risk of not knowing whether or not acceptable interlocking profiles have been provided and in order to complete the continuous strip in a form which is suitable for storage without deforming the profiles or damaging the film adjacent the profiles.
25 Methods heretofore have been employed wherein tubular film has been formed and folded in such a way so as to simultaneously make dual bags with each cross seal-ny operation. However, a feature of the present invention is to provide a method and mechanism for making a ~L2~;499 double double tube wherein material for four bags is formed. The difficulty in forming a double double tube is to handle the large amount of film emanating from the extruder, collapsing the bubble of the film so that 5 the profiles are aligned and joined and handled in such a manner so that usable strips of profile film are pro-vided which can be formed into four bags. The handling of such a tube creates problems in where the tube is to be slit, which profiles are to be joined to each other, 10 and the collapsing of the bubble in such a manner that a fold mark is formed where the natural fold of the eventual bag will occur.
It is accordingly an object of the present invention to provide an improved apparatus for forming 15 a unique tubing which is capable of being converted into four reclosable bags at cne time by a single cross-cutting and sealing arrangement. More parti-cularly, the method and apparatus of the invention provides double double profile film sets or in other 20 words, two sets of double profile film.
A further object of the invention is to provide a unique manner of slitting and foldinq and joining profiles in a tubing so that strips of double profile film for conversion into two sets of double bag 25 film strips are formed.
A feature of the present invention is the formation of a continuous tube of film with eight profiles on the inner surface, and finding a satis-factory way of joining said profiles so as to form 30 profile film strips that can be readily converted into sets of reclosable bags. One unsatisfactory manner of approaching the problem is to roll the tube into a spool after aligning the profiles, but not joining them, so that the tube is folded between profiles and 5 then separating anc1 rejoining the tube suctions later at the bag machine. This situation creates the problem of not knowing whether or not the profiles are satis-factory until much later.
Another alternative unsatisfactory solution to l0 handling the tube is to slit the tuhe into two sections which would have to be joined onto themselves and spooled.
A feature oE the invention is the making of a quadruple profile tube which is then divided into two 15 sets of double profile film wherein the profile from one of the film sections is folded into the other film sections and vice-versa. In this manner, production output can be increased substantially since two double profile films for conversion into reclosable bags are 20 provided from one quadruple profile tube.
Pursuant to the present invention, there is provided an apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the con~ronting top edges, comprising means 25 for extruding a continuous tube with pairs of closely spaced interlocking elements on the surface of the tube, the total pairs being a multiple of 2 with at least 4 pairs on the tube; means for slitting the tube leng~hwise between profiles of alternate pairs; and 30 means for folding the tube between each adjacent pair s~
for bringing the profile adjacellt the slit over onto the closest profile of the pair which has not been slit.
There is also provided by the present inven-5 tion a mechanism for making fle~ible plastic bags withintegral pressure interlocking rib and groove elements on the confronting ~op edges comprising in combination an extruder die for extruding a continuous tube having die openings shaped and spaced to form on the inner 10 surface of the tube a first pair of closely spaced r:ib elements and a second pair of closely spaced rih ele-ments diametrically opposed from the first; a first pair of closely spaced groove elements intermediate the pairs of rib elements and a second pair of closely 15 spaced groove elements diametriclly opposed from the first pair of groove elements with the groove e~ements being of the size and shape to pressure interlock with the rib elements; and first and second cutters for continuously longitudinally cutting the tube at a first 20 location between one of said pair of rib or groove ele-ments and at a second location between the other of said pair of rib or groove elements.
Other objects, advantages and features, as well as equivalent methods and apparatuses which are 25 intended to be covered herein, will become more appar-ent from the -teacnings of the present invention in connection with the disclosu.re of the preferred embod-iment thereof i.n the specification, claims, and draw-ings, in which:
ON THE DRAWIN~S
-FIG. 1 is a perspective view of aa tubular plastic profile film being extruded and formed into separate double proEile film strips in accordance with 5 the principles of the present invention;
FIG. 2 is an enlarged detailed sectional v.iew taken ~bst~ntially along the line Il-II and illus-trating mechanism which is added to the showing of FIG.
1 to accomplish the function shown schematically in 10 FIG. l;
FIG. 3 is a perspective view of a bag of the type which will result from the manufacturi.ng arrange-ment illustrated;
FIG. 4 is a vertical sectional view through 15 the bag of FIG. 3 taken substantially along line IV-IV;
FIG. 5 is a view of a secondary form of quad-ruple profile tubing, FIG. 1 illustrating the preferred form; and FIG. 6 is a perspective view illustrating the 20 manner of handling each of the dual double strips formed by the method of FIG. 1.
As illustrated in FIG. 1, an extruder 10 is provided with molten plastic which is pressure extruded through an annular slot to form a continuous film tube 25 11. The slvt ls shaped so as to form on the inner sur-face of the tube a series of eight profiles. The profiles are of the rib anA groove type and are of complementary shape and size so as to be pressure interlockable and separable fcr forming reclosable 3G fasteners at the confronting top edges of plastic film 4~9 bags such as illustrated in FIGS. 3 and 4.
On the inner surface of the film is a first pair 12 of closely spaced male profiles or ribs 12a and 12b. Diametrically opposite this location relative to 5 the tubular film is a second pair 13 of ribs 13a and 13b which are also closely spaced.
Circumferentially between the diametrically opposite pairs 12 and 13 is a pair 14 of closely spaced female profiles or grooves 14a and 14b. Diametrically 10 opposite the pair 14 i5 a second pair 15 of closely spaced grooves 15a and 15b. The spacing between the rib elements and groove elements is sufficient to provide material for pull flanges as shown in the finished bag of FIGS. 3 and 4.
As the tube is extruded and becomes prelimi-narily cooled, it is flattened against the resistance of the air bubble within the tube in a manner so as to align the first pair 12 of ribs with the first pair 14 of grooves thereby forming a first set 16. Similarly, 20 the second pair 13 of ribs is aligned with the second pair 15 of grooves forming a second set 17 of ribs and grooves.
The collapsing of the tube into this alignment may occur by utilizing spaced rolls or guides correctly 25 positioned in relationship to the ribs and grooves as they appear on the film tube.
The next step includes cutting or slitting the tube longitudinally continuously with knives 45 and 46 to form slits shown at 47 and 48 respectively. The 30 slit formed by the knife 45 is midway between the first pair 12 of profi:Les which is in the upper layer of the tube which is folded a~ its lateral side edges 20 and 21. The slit formed by the knife 46 is midway between the second pair 13 of ribs on the lower layer of the 5 tube. The slits are simultaneously made, but al~er-natively either slit can be made in advance of the other, but both slits must be completed before the tube is foldedO
In the next step which uniquely forms strips 10 18 and lg of profile film for conversion into double bags, the severed film is folded in such a manner so as to form two dual profile film strips. The folding is accomplished by a suitable guidance structure such as that shown in FIG. 2 where the profile 12a from the 15 first set 16 is folded over onto the second set 17 to be interengaged with the groove 14 simultaneously with the interengagement of profiles 12b and 15b.
As substantially the same time, the proile 13a from the second set 17 is folded over onto the 20 first set to be interengaged with the groove 15a, while simultaneously therewith profiles 13b and 14b ale being interengaged. This unique folding provides the two double profile film strips 18 and 19 which are utilized to form bags in the manner illustrated in FIG. 6.
FIG. 2 illustrates the manner in which the folding may be accomplished. An edge guide such as 39 having a concave groove m~y be provided to receive the doubled edges 20 or 21 of the film strip 16 and 17, and shaped metal or plastic guide strips hold the groove 30 elements l~a and L4b in place as illustrated by the backing pla~e 33 a]ld the guide plates 34, 35 and 35.
The rib 13b is guided and pressed to interlock in~o the groove 14b by shaped plates 34a and 35a and backing plate 33a.
The rib 12a is brought over onto the second set 17 by curved plates 37 and 38 and backing plate 38a which bring the rib 12a along the path in~icated by the broken lines into the dotted line position of 12a where it is pressed into the groove 14a. A similar mechanism 10 is provide~ for folding the lower layer of the film to bring the rib 13a into the groove 15a.
The resu:Ltant dual double profile film strips 18 and 19 are formed into bags by cross-cutting and sealing. The resultant bags are illustrated in FIGS. 3 15 and 4. The plastic film bags such as shown as 25 have a folcled bottom 29 and cut and sealed side edges 30 and 31. The profiles are 30ined at 26 with groove profile 26a receiving rib profile 26b. Above the profiles are short flarlges 27 and 28 which permit the user to pull 20 the profiles apart: for in opening the bag.
FIG. 5 illustrates a modified and less desir-able form of film, but one which is constructed in accordance with the principles of the present inven-tion. In the film of FIG. 5, a first pair 41 of 25 profiles is located within the tube 40, and a second pair 42 of profiles is located diametrically opposite the first pair 41. A third pair 43 of profiles is located between the first and second pair, and a fourth pair 44 is positioned diametrically opposite the third 30 pair 43. Each pair consists of a male and female with their locations being alternated as the tube is viewed progressing clockwise or counter-clockwise within the tube.
When the tube of FIG. 5 is slit, the first 5 slit, which is ma~e by the knife 45 will be located between the profiles of the first pair 41, and the groove element 41a will be folded over onto the rib element 43a. The second slit will be made by the knife 46 between the profiles of the second pair 42, and the 10 groove profile 42a will be folded over onto the rib profile 44a, in the same manner as illustrated in FIG.
1.
With reference to FIG. 1, the knives 45 and 46 may be located so that instead of cutting between the 15 rib elements, they cut between the groove elements. In such arrangement, knife 45 will cut a slit between the groove elements 15a and 15b of the pair 15, and the knife 46 will slit midway between the groove elements 14a and 14b of the pair 14. W'nen the slits are made, 20 the tube will be folded so that the groove 15a is brought over onto the rib 13a. The groove 14a will be brought over onto the rib 12a. Similarly, with respect to the arrangement shown in FIG. 5, slits may be ma~e between the pairs 43 and 44, and the tube would be 25 folded to align the rib and profile elements. In each case the folding will result in double bag strips such as 18 and 19 in FIG. 1.
As the two double profile film strips 18 and 19 are formed, they are wound onto rolls 22 and 23.
30 These rolls may either be used separated to form two _g_ ~2~54~
bags or simultaneously used to form four bags. As illustrated in FIG. 6, the roll 22 is unrolled with the profile film strip 18 being fed into a perforation device 50 which forms a longitudinal line of perfora-5 tions 51 in the tube layer opposite the slit 48. Thetubing is then fed into a sealing and cutting mechanism 52 wherein spaced cross-seals are made to form side seals such as 53 and 54 at the edges of the bags and the bags are cut apart at their side edges. The bags 10 are stacked in a stacking tray 55, and when removed, can be torn apart at their top edges to separate the stacks 56 and 57 at the center separation 58. The separate stacks then may be banded such as shown by bands 59 and 60.
While preferred forms are illustrated, tubing may be extruded with 12 profilès on the inner surface or with 16, or any additional multiples divisible by 4. Each set of 4 profiles will form an additional double bag strip, and the total number is limited only 20 by the capability of handling the material and the size of the die and the equipment which must be provided.
In each instance where additional profiles are added in multiples of 4, the same positional relationship of profiles is used with pairs of closely spaced elements 25 and slits made between alternate pairs, and one profile adjacent the slit folded over onto the profile next to lt. The pairs are arranged relatively close to each other, slits are made in alternate pairs around the periphery of the tubing, and the profiles are brought 30 together to mate with the profile which is adjacent it in the next pair. The spacing between pairs, of course, is chosen dependent on ~he size of the bag which is to be produced as will be apparent from the resultant bag shown in FIGS. 3 and 4. Tne closeness of 5 the profiles in each pair will be chosen in accordance with the length of the flap or flange at the top of the bag. As will be understood from the foregoing descrip-tion, when tubing is extruded with 12 or more profiles on the inner surface, slits are made between alternate 10 pairs of profiles, and the pairs of profiles in a 12 profile bag are not diametrically opposite each another. In accordance with the present invention, the tubing is extruded with at least 4 pairs of profiles, and the pairs can be increased, but must be done so in 15 multiples of 2. In some instances, it may be desirable to locate the profiles on the external surface of the tubing, although the profile location on the ~nner surface is preferred.
Thus, it will be seen that we have provided an 20 improved method and mechanism which meets the objec-tives above set forth and which is capable of utiliza-tion for increasing output and reducing scrap rate.
The mechanism doubles the production of structures which are capable of producing dual bags and quadruples 25 the output of structures which produce single bags without disadvantages to the resultant bag structure.
The invention relates to improvements in apparatus for making plastic film bags having reclos-able fasteners thereon, and particularly of the type 5 having opposed in~erlocking rib and groove elements on the confronting top edges of the bags.
In the manufacture of bags of this type, continual efforts are being made to increase the speed of production output to thereby effect a saving in cost of the individual bags. There are factors which limit 10 the speed cf extrusion of the film and speed of joining of profiles so that the present concept embodies manu-facturing simultaneously a plurality of bags in a unique manner so that actually, material for making four bags with each cross-sealing operation is produced 15 simultaneously in a single tubular extrusion film.
Attempts to make multiple bags in a single extrusion operation encounter the problems of control-ling the film and controlling the profiles. The pro-files are joined before the film is wound or spooled in 20 order to avoid the risk of not knowing whether or not acceptable interlocking profiles have been provided and in order to complete the continuous strip in a form which is suitable for storage without deforming the profiles or damaging the film adjacent the profiles.
25 Methods heretofore have been employed wherein tubular film has been formed and folded in such a way so as to simultaneously make dual bags with each cross seal-ny operation. However, a feature of the present invention is to provide a method and mechanism for making a ~L2~;499 double double tube wherein material for four bags is formed. The difficulty in forming a double double tube is to handle the large amount of film emanating from the extruder, collapsing the bubble of the film so that 5 the profiles are aligned and joined and handled in such a manner so that usable strips of profile film are pro-vided which can be formed into four bags. The handling of such a tube creates problems in where the tube is to be slit, which profiles are to be joined to each other, 10 and the collapsing of the bubble in such a manner that a fold mark is formed where the natural fold of the eventual bag will occur.
It is accordingly an object of the present invention to provide an improved apparatus for forming 15 a unique tubing which is capable of being converted into four reclosable bags at cne time by a single cross-cutting and sealing arrangement. More parti-cularly, the method and apparatus of the invention provides double double profile film sets or in other 20 words, two sets of double profile film.
A further object of the invention is to provide a unique manner of slitting and foldinq and joining profiles in a tubing so that strips of double profile film for conversion into two sets of double bag 25 film strips are formed.
A feature of the present invention is the formation of a continuous tube of film with eight profiles on the inner surface, and finding a satis-factory way of joining said profiles so as to form 30 profile film strips that can be readily converted into sets of reclosable bags. One unsatisfactory manner of approaching the problem is to roll the tube into a spool after aligning the profiles, but not joining them, so that the tube is folded between profiles and 5 then separating anc1 rejoining the tube suctions later at the bag machine. This situation creates the problem of not knowing whether or not the profiles are satis-factory until much later.
Another alternative unsatisfactory solution to l0 handling the tube is to slit the tuhe into two sections which would have to be joined onto themselves and spooled.
A feature oE the invention is the making of a quadruple profile tube which is then divided into two 15 sets of double profile film wherein the profile from one of the film sections is folded into the other film sections and vice-versa. In this manner, production output can be increased substantially since two double profile films for conversion into reclosable bags are 20 provided from one quadruple profile tube.
Pursuant to the present invention, there is provided an apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the con~ronting top edges, comprising means 25 for extruding a continuous tube with pairs of closely spaced interlocking elements on the surface of the tube, the total pairs being a multiple of 2 with at least 4 pairs on the tube; means for slitting the tube leng~hwise between profiles of alternate pairs; and 30 means for folding the tube between each adjacent pair s~
for bringing the profile adjacellt the slit over onto the closest profile of the pair which has not been slit.
There is also provided by the present inven-5 tion a mechanism for making fle~ible plastic bags withintegral pressure interlocking rib and groove elements on the confronting ~op edges comprising in combination an extruder die for extruding a continuous tube having die openings shaped and spaced to form on the inner 10 surface of the tube a first pair of closely spaced r:ib elements and a second pair of closely spaced rih ele-ments diametrically opposed from the first; a first pair of closely spaced groove elements intermediate the pairs of rib elements and a second pair of closely 15 spaced groove elements diametriclly opposed from the first pair of groove elements with the groove e~ements being of the size and shape to pressure interlock with the rib elements; and first and second cutters for continuously longitudinally cutting the tube at a first 20 location between one of said pair of rib or groove ele-ments and at a second location between the other of said pair of rib or groove elements.
Other objects, advantages and features, as well as equivalent methods and apparatuses which are 25 intended to be covered herein, will become more appar-ent from the -teacnings of the present invention in connection with the disclosu.re of the preferred embod-iment thereof i.n the specification, claims, and draw-ings, in which:
ON THE DRAWIN~S
-FIG. 1 is a perspective view of aa tubular plastic profile film being extruded and formed into separate double proEile film strips in accordance with 5 the principles of the present invention;
FIG. 2 is an enlarged detailed sectional v.iew taken ~bst~ntially along the line Il-II and illus-trating mechanism which is added to the showing of FIG.
1 to accomplish the function shown schematically in 10 FIG. l;
FIG. 3 is a perspective view of a bag of the type which will result from the manufacturi.ng arrange-ment illustrated;
FIG. 4 is a vertical sectional view through 15 the bag of FIG. 3 taken substantially along line IV-IV;
FIG. 5 is a view of a secondary form of quad-ruple profile tubing, FIG. 1 illustrating the preferred form; and FIG. 6 is a perspective view illustrating the 20 manner of handling each of the dual double strips formed by the method of FIG. 1.
As illustrated in FIG. 1, an extruder 10 is provided with molten plastic which is pressure extruded through an annular slot to form a continuous film tube 25 11. The slvt ls shaped so as to form on the inner sur-face of the tube a series of eight profiles. The profiles are of the rib anA groove type and are of complementary shape and size so as to be pressure interlockable and separable fcr forming reclosable 3G fasteners at the confronting top edges of plastic film 4~9 bags such as illustrated in FIGS. 3 and 4.
On the inner surface of the film is a first pair 12 of closely spaced male profiles or ribs 12a and 12b. Diametrically opposite this location relative to 5 the tubular film is a second pair 13 of ribs 13a and 13b which are also closely spaced.
Circumferentially between the diametrically opposite pairs 12 and 13 is a pair 14 of closely spaced female profiles or grooves 14a and 14b. Diametrically 10 opposite the pair 14 i5 a second pair 15 of closely spaced grooves 15a and 15b. The spacing between the rib elements and groove elements is sufficient to provide material for pull flanges as shown in the finished bag of FIGS. 3 and 4.
As the tube is extruded and becomes prelimi-narily cooled, it is flattened against the resistance of the air bubble within the tube in a manner so as to align the first pair 12 of ribs with the first pair 14 of grooves thereby forming a first set 16. Similarly, 20 the second pair 13 of ribs is aligned with the second pair 15 of grooves forming a second set 17 of ribs and grooves.
The collapsing of the tube into this alignment may occur by utilizing spaced rolls or guides correctly 25 positioned in relationship to the ribs and grooves as they appear on the film tube.
The next step includes cutting or slitting the tube longitudinally continuously with knives 45 and 46 to form slits shown at 47 and 48 respectively. The 30 slit formed by the knife 45 is midway between the first pair 12 of profi:Les which is in the upper layer of the tube which is folded a~ its lateral side edges 20 and 21. The slit formed by the knife 46 is midway between the second pair 13 of ribs on the lower layer of the 5 tube. The slits are simultaneously made, but al~er-natively either slit can be made in advance of the other, but both slits must be completed before the tube is foldedO
In the next step which uniquely forms strips 10 18 and lg of profile film for conversion into double bags, the severed film is folded in such a manner so as to form two dual profile film strips. The folding is accomplished by a suitable guidance structure such as that shown in FIG. 2 where the profile 12a from the 15 first set 16 is folded over onto the second set 17 to be interengaged with the groove 14 simultaneously with the interengagement of profiles 12b and 15b.
As substantially the same time, the proile 13a from the second set 17 is folded over onto the 20 first set to be interengaged with the groove 15a, while simultaneously therewith profiles 13b and 14b ale being interengaged. This unique folding provides the two double profile film strips 18 and 19 which are utilized to form bags in the manner illustrated in FIG. 6.
FIG. 2 illustrates the manner in which the folding may be accomplished. An edge guide such as 39 having a concave groove m~y be provided to receive the doubled edges 20 or 21 of the film strip 16 and 17, and shaped metal or plastic guide strips hold the groove 30 elements l~a and L4b in place as illustrated by the backing pla~e 33 a]ld the guide plates 34, 35 and 35.
The rib 13b is guided and pressed to interlock in~o the groove 14b by shaped plates 34a and 35a and backing plate 33a.
The rib 12a is brought over onto the second set 17 by curved plates 37 and 38 and backing plate 38a which bring the rib 12a along the path in~icated by the broken lines into the dotted line position of 12a where it is pressed into the groove 14a. A similar mechanism 10 is provide~ for folding the lower layer of the film to bring the rib 13a into the groove 15a.
The resu:Ltant dual double profile film strips 18 and 19 are formed into bags by cross-cutting and sealing. The resultant bags are illustrated in FIGS. 3 15 and 4. The plastic film bags such as shown as 25 have a folcled bottom 29 and cut and sealed side edges 30 and 31. The profiles are 30ined at 26 with groove profile 26a receiving rib profile 26b. Above the profiles are short flarlges 27 and 28 which permit the user to pull 20 the profiles apart: for in opening the bag.
FIG. 5 illustrates a modified and less desir-able form of film, but one which is constructed in accordance with the principles of the present inven-tion. In the film of FIG. 5, a first pair 41 of 25 profiles is located within the tube 40, and a second pair 42 of profiles is located diametrically opposite the first pair 41. A third pair 43 of profiles is located between the first and second pair, and a fourth pair 44 is positioned diametrically opposite the third 30 pair 43. Each pair consists of a male and female with their locations being alternated as the tube is viewed progressing clockwise or counter-clockwise within the tube.
When the tube of FIG. 5 is slit, the first 5 slit, which is ma~e by the knife 45 will be located between the profiles of the first pair 41, and the groove element 41a will be folded over onto the rib element 43a. The second slit will be made by the knife 46 between the profiles of the second pair 42, and the 10 groove profile 42a will be folded over onto the rib profile 44a, in the same manner as illustrated in FIG.
1.
With reference to FIG. 1, the knives 45 and 46 may be located so that instead of cutting between the 15 rib elements, they cut between the groove elements. In such arrangement, knife 45 will cut a slit between the groove elements 15a and 15b of the pair 15, and the knife 46 will slit midway between the groove elements 14a and 14b of the pair 14. W'nen the slits are made, 20 the tube will be folded so that the groove 15a is brought over onto the rib 13a. The groove 14a will be brought over onto the rib 12a. Similarly, with respect to the arrangement shown in FIG. 5, slits may be ma~e between the pairs 43 and 44, and the tube would be 25 folded to align the rib and profile elements. In each case the folding will result in double bag strips such as 18 and 19 in FIG. 1.
As the two double profile film strips 18 and 19 are formed, they are wound onto rolls 22 and 23.
30 These rolls may either be used separated to form two _g_ ~2~54~
bags or simultaneously used to form four bags. As illustrated in FIG. 6, the roll 22 is unrolled with the profile film strip 18 being fed into a perforation device 50 which forms a longitudinal line of perfora-5 tions 51 in the tube layer opposite the slit 48. Thetubing is then fed into a sealing and cutting mechanism 52 wherein spaced cross-seals are made to form side seals such as 53 and 54 at the edges of the bags and the bags are cut apart at their side edges. The bags 10 are stacked in a stacking tray 55, and when removed, can be torn apart at their top edges to separate the stacks 56 and 57 at the center separation 58. The separate stacks then may be banded such as shown by bands 59 and 60.
While preferred forms are illustrated, tubing may be extruded with 12 profilès on the inner surface or with 16, or any additional multiples divisible by 4. Each set of 4 profiles will form an additional double bag strip, and the total number is limited only 20 by the capability of handling the material and the size of the die and the equipment which must be provided.
In each instance where additional profiles are added in multiples of 4, the same positional relationship of profiles is used with pairs of closely spaced elements 25 and slits made between alternate pairs, and one profile adjacent the slit folded over onto the profile next to lt. The pairs are arranged relatively close to each other, slits are made in alternate pairs around the periphery of the tubing, and the profiles are brought 30 together to mate with the profile which is adjacent it in the next pair. The spacing between pairs, of course, is chosen dependent on ~he size of the bag which is to be produced as will be apparent from the resultant bag shown in FIGS. 3 and 4. Tne closeness of 5 the profiles in each pair will be chosen in accordance with the length of the flap or flange at the top of the bag. As will be understood from the foregoing descrip-tion, when tubing is extruded with 12 or more profiles on the inner surface, slits are made between alternate 10 pairs of profiles, and the pairs of profiles in a 12 profile bag are not diametrically opposite each another. In accordance with the present invention, the tubing is extruded with at least 4 pairs of profiles, and the pairs can be increased, but must be done so in 15 multiples of 2. In some instances, it may be desirable to locate the profiles on the external surface of the tubing, although the profile location on the ~nner surface is preferred.
Thus, it will be seen that we have provided an 20 improved method and mechanism which meets the objec-tives above set forth and which is capable of utiliza-tion for increasing output and reducing scrap rate.
The mechanism doubles the production of structures which are capable of producing dual bags and quadruples 25 the output of structures which produce single bags without disadvantages to the resultant bag structure.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the confronting top edges, comprising: means fox extruding a continuous tube with pairs of closely spaced interlocking elements on the surface of the tube, the total pairs being a multiple of two with at least four pairs on the tube; means for slitting the tube lengthwise between profiles of alternate pairs; and means for folding the tube between each adjacent pair for bringing the profile adjacent the slit over onto the closest profile of the pair which has not been slit.
2. A mechanism for making flexible plastic bags with integral pressure interlocking rib and groove elements on the confronting top edges comprising in combination: an extruder die for extruding a continuous tube having die openings shaped and spaced to form on the inner surface of the tube a first pair of closely spaced rib elements and a second pair of closely spaced rib elements diametrically opposed from the first; a first pair of closely spaced groove elements inter-mediate the pairs of rib elements and a second pair of closely spaced groove elements diametrically opposed from the first pair of groove elements with the groove elements being of the size and shape to pressure interlock with the rib elements;
and first and second cutters for continuously longitudinally cutting the tube at a first location between one of said pair of rib or groove elements and at a second location between the other of said pair of rib or groove elements.
and first and second cutters for continuously longitudinally cutting the tube at a first location between one of said pair of rib or groove elements and at a second location between the other of said pair of rib or groove elements.
3. A mechanism for making flexible plastic bags with integral interlocking rib and groove elements on the confronting top edges in accordance with claim 2: including means for aligning adjacent pairs of rib and groove elements so that first and second sets are formed of the aligned rib and groove elements; and means for folding said sets to bring one of the elements adjacent each of said slits from its set over into the other set to be interlocked.
4. Apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the confronting top edges, comprising: means for extruding a continuous tube with a first pair of closely spaced interior rib elements, a second pair of closely spaced interior rib elements diametrically opposed from the first pair, a first pair of closely spaced interior groove elements intermediate the pairs of rib elements, and a second pair of closely spaced interior groove elements diametrically opposed from the first pair of groove elements; means for slitting the tube between the elements of each of the pairs of groove elements or each of the pairs of rib elements; and means for folding the slit tube to form two profile films for con-version into sets of interlocking bags.
5. Apparatus according to claim 4, including means for flattening the tube and aligning each of the pair of rib elements with an adjacent pair of groove elements for forming first and second profile film sets with each set including two aligned rib and groove elements.
6. Apparatus according to claim 5, including means for joining in interlocked relationship opposed rib and groove elements.
7. Apparatus according to claim 6, including means for rolling each of the strips into a roll.
8. Apparatus according to claim 4, wherein said folding means further includes means for aligning the rib elements of the first pair with the groove elements of the first pair and for aligning the rib elements of the second pair with the groove elements of the second pair to form first and second sets, and for bringing one element of each of said sets adjacent to said slit over to the other element of each set by folding the film into the other set.
9. Apparatus according to claim 8, wherein said folding means is arranged for flattening the film for each of the sets and for interlocking the rib and groove elements of the sets.
10. Apparatus for making a plastic film structure for forming bags with integral pressure interlocking rib and groove elements on the confronting top edges, comprising: means for forming a continuous one-piece tube having on the inner surface thereof a first pair of closely spaced interlocking elements, a second pair of closely spaced interlocking elements, a third pair of closely spaced interlocking elements intermediate the first and second pairs, and a fourth pair of closely spaced interlocking elements positioned diametrically opposed to the third pair, and each of the pairs including a rib and groove element with the rib and groove elements alternating in a circumferential direction around the tube; means for flattening said tube so that the first and fourth pair are aligned and the second and third pair are aligned to form first and second sets; means for slitting the tube longitudinally through one layer of the first set and through the opposite layer of the second set; and means for folding one of the elements of the first set adjacent to the first slit over onto the second set and for folding another of said elements of the second set adjacent the second slit over onto the first set.
11. Apparatus for making flexible plastic bags with integral pressure interlocking rib and groove elements on the confronting top edges, comprising: means for extruding a continuous tube with a first pair of closely spaced interlocking elements and a second pair of closely spaced interlocking elements diametrically opposed from the first pair, a third pair of closely spaced interlocking elements intermediate the first and second pairs and a fourth pair diametrically opposed to the third pair, and said interlocking elements being on the inner surface of the tube; means for flattening the tube so that said first and fourth pair of interlocking elements are aligned and said second and third pair of interlocking elements are aligned to form first and second film sets; means for forming a first slit through one layer of the first set and a second slit through the opposite layer of the second set;
and means for folding one of said profiles of the first set adjacent said first slit over into the second set, and another of said profiles of said second set and adjacent said second slit over into first set.
and means for folding one of said profiles of the first set adjacent said first slit over into the second set, and another of said profiles of said second set and adjacent said second slit over into first set.
12. Apparatus for making a plastic film structure for forming bags with integral pressure interlocking rib and groove elements on the confronting top edges comprising: means for forming a continuous one-piece tube having on the inner surface thereof a first pair of closely spaced interlocking elements, a second pair of closely spaced interlocking elements, a third pair of closely spaced interlocking elements inter-mediate the first and second pairs, and a fourth pair of closely spaced interlocking elements positioned diametrically opposed to the third pair, each of said pairs including a rib and groove elements with the rib and groove elements alternating in a circumferential direction around the tube; means for flattening said tube so that the first and fourth pairs are aligned and the second and third pairs are aligned to form first and second sets; means for slitting the tube longitudinally through one layer of the first set and through the opposite layer of the second set; and means for folding one of the elements of the first set adjacent to the first slit over onto the second set and for folding another of said elements of the second set adjacent to the second slit over onto the first set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000544001A CA1245499A (en) | 1983-03-03 | 1987-08-07 | Apparatus for making quadruple profile plastic tubing for bags |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/471,740 US4563319A (en) | 1983-03-03 | 1983-03-03 | Method of making quadruple profile tubing |
| US471,740 | 1983-03-03 | ||
| CA000448775A CA1230317A (en) | 1983-03-03 | 1984-03-02 | Quadruple profile tubing |
| CA000544001A CA1245499A (en) | 1983-03-03 | 1987-08-07 | Apparatus for making quadruple profile plastic tubing for bags |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000448775A Division CA1230317A (en) | 1983-03-03 | 1984-03-02 | Quadruple profile tubing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1245499A true CA1245499A (en) | 1988-11-29 |
Family
ID=25670315
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000544001A Expired CA1245499A (en) | 1983-03-03 | 1987-08-07 | Apparatus for making quadruple profile plastic tubing for bags |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1245499A (en) |
-
1987
- 1987-08-07 CA CA000544001A patent/CA1245499A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |