US3447987A - Method and apparatus for sealing bags - Google Patents

Description

June 3, 1969 Q. H. WILLIAMS METHOD AND APPARATUS FOR SEALING BAGS Sheet Filed Feb. 2, 1966 Sheet Q. H. WILLIAMS METHOD AND APPARATUS FOR SEALING BAGS :7 AK 14 l h Filed Feb. 2, 1966 June 3, 1969 Jun 3, 1969 w ms 3,447,987

METHOD AND APPARATUS FOR SEALING BAGS Filed Feb. 2. 1966. Sheet 3 of 8 June 3, 1969 Q. H. WILLIAMS METHOD AND APPARATUS FOR SEALING BAGS Filed Feb. 2, 1966 June 3, 1969 Q. H. WILLIAMS 3,4 7,987

METHOD AND APPARATUS FOR SEALING BAGS Filed Feb. 2. 1966 Sheet 5 of a June 3, 1969 Q. H. WILLIAMS METHOD AND APPARATUS FOR SEALING BAGS Sheet Filed Feb. 2, 1966 June 3, 1969 Q. H. WILLIAMS 3, 7,9 7

METHOD AND APPARATUS FOR SEALING BAGS Filed Feb. 2, 1966 Sheet 7 of a I l I I I! l I l [I i ////////2 I i G June 3, 1969 I Q. H. WILLIAMS 3,447,937

METHOD AND APPARATUS FOR SEALING BAGS I Filed Feb. 2. 1966 Sheet United States Patent 3,447,987 METHOD AND APPARATUS FOR SEALING BAGS Quentin H. Williams, 3109 Delaney St., Dayton, Ohio 45420 Filed Feb. 2, 1966, Ser. No. 524,415 Int. Cl. B32b 7/14; B65b 7/06 US. Cl. 15693 11 Claims ABSTRACT OF THE DISCLOSURE This invention relates to methods and apparatus for sealing the ends of bags. More particularly, the invention relates to methods and apparatus for applying a tape over the ends of a bag and attaching the tape tabs to the body of the bag.

In the manufacture of multi-wall paper bags tape over sewn closures are commonly used. Difiiculty has been encounter in providing a sealed end for multi-wall bags of 0 sufficient tightness to prevent the infestation of the contents of the bag by very small insects. Ordinary adhesives did not provide sufiicient adherence of the commonly used paper tape over the line of stitching to prevent ingress of insects. The advent of hot melt adhesive made it possible to secure good bonding of the tape over the line of thread stitching. However, small insects could still penetrate the bag through the thread channels of the cut tape abs. Additionally, another path for insert ingress is provided adjacent the edge of the bag where the folded over tape comes together to form the outwardly projecting tabs on either side of the bag. The problem was particularly acute in multi-wall bags having three or four plies which increased the thickness of the side edges of the bag, thus rendering it more difficult to effect a seal on the paper tape tab ends. US. Patent 3,190,539 discloses a construction for an end closure on a bag which eliminates the channels through which insects can enter a bag. According to the foregoing patent, it has been found that by turning the extending tab portions back against the face of the bag and adhesively attaching them firmly thereto the small opening normally adjacent the edge of the bag can be closed. By using a hot melt adhesive, i.e., one having a polyethylene base to secure the tape over the line of stitching, an insectproof seal can be obtained for the end of a bag. Additionally, adhesively attaching the tab ends of the closure tape to the face of the bag prevents these tabs from being torn or pulled loose when the bag is being handled in transit. The bags described in the foregoing patent have heretofore had the tape tabs adhesively attached to the sidewalls of the bag by hand labor. Thus, a need exists for a method and apparatus for carrying out the end sealing which avoids the hand labor.

The method and apparatus of the present invention is particularly useful in producing bags which meet government specifications for use in shipping dried milk.

It is an object of the present invention to provide a method and apparatus for sealing the ends of a bag whereby an insert-proof seal is effected.

It is also an object of the present invention to provide a method and apparatus which automatically turns back ice the tab ends on the closure tape and seals the tab ends to the bag face.

It is a further object of the present invention to provide a method and apparatus which can provide an insert-proof seal for the end of multi-wall bags which does not require the use of hand labor.

An additional object of the present invention is to provide a method and apparatus for sealing the ends of bags using thread stitching and a folded tape closure over the Stitching.

The apparatus aspect of the present invention is provided in an apparatus for sealing the ends of bags which includes means for conveying a series of bags and means for continuously applying a strip of closure tape to at least one flattened end of the bags. Means are also pro vided for severing the tape between adjacent bags to provide a leading tape tab and a trailing tape tab extending outwardly from the respective side edges of each adjacent bag. Means for applying an adhesive to one surface of the tape tabs is also provided. Also, means for turning the tape tabs back along a line coinciding with the sideedges of each of said bags to secure the tape tabs to their respective bag is provided.

The method aspect of the present invention is provided in a method which includes the step of conveying a plurality of bags, each having at least one flattened open end, arranged in side-by-side relationship in a direction parallel to said open end; continuously adhesively applying a strip of closure tape to the open ends of the bags; severing the tape between adjacent bags to provide a leading tape tab and a trailing tab extending outwardly from the respective side edge of each adjacent bag; applying an adhesive to one surface of the tape tabs; and folding the leading tape tab backward and the trailing tape tab forward along a line coinciding with the side edges of the bag to bring the surface having the adhesive thereon into contact with the bag.

Other objects, features and advantages of the invention will appear from the description given hereinafter, taken in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of one embodiment of the apparatus of the present invention;

FIG. 2 is a perspective view of a bag showing the folding back of the tape tabs;

FIG. 3 is a perspective view of the bag showing the completed folds on the tape tabs;

FIG. 4 is an enlarged view of the tape cutter-adhesive applicator portion of the apparatus which is shown within bracket 4 of FIG. 1;

FIG. 5 is an enlarged view of the leading ta=b turner assembly portion of the apparatus shown within the bracket5ofFIG. 1;

FIG. 5A is a view along line 5A5A of FIG. 5;

FIG. 5B is a view of a portion of the assembly of FIG. 5 showing the start of the foldback on the leading tab;

FIG. 5C is a view similar to FIG. 5B showing the last steps in the foldback of the leading tab;

FIG. 5D is a view similar to FIG. 5B showing the leading tab under the pressure foot;

FIG. SE is a view similar to FIG. 5B showing the position of the assembly as the trailing tab passes underneath; FIG. SP is a view along line 5F5F of FIG. 5;

FIG. 6 is an enlarged view of the trailing tab turner assembly portion of the apparatus shown within bracket 6 of FIG. 1;

FIG. 6A is an enlarged fragmentary view of the segment gear section of the assembly of FIG. 6;

FIG. 6B is an enlarged fragmentary view of the trailing flap pressure -foot-chain assembly seen in FIG. 6;

FIG. 6C is a sectional view along line 6C6C of FIG.

FIG. 6D is a sectional view along line 6D6D of FIG. 6; and

FIG. 7 is a sectional view of the pressure roll assembly portion of the apparatus shown within the bracket 7 of FIG. 1.

Referring now to FIGS. 1, 2 and 3, the apparatus for closing the end of bags, designated generally by the numeral 15, is supported on a base structure 16. A conveyor assembly (not shown) delivers a plurality of paper bags in side-by-side arrangement. The bags have their open ends positioned parallel to the direction of movement. The plurality of paper bags enter the apparatus from the righthand side as seen in FIG. 1 and exit from the left-hand side. The direction of travel is indicated by the arrows in FIGS. 2 and 3. The bag 17 is conveyed through the apparatus by a series of lugs 44 (see FIG. 6C) projecting upwardly from a chain driven conveyor belt (not shown). The bags first pass through a sewing machine 18 where a line of thread stitching is passed through the end of each bag. The bag next moves to the tape applying station where a strip of tape 19 is folded over the sewn end of the bag and adhesively sealed thereto. The tape used to cover the stitching line may be any suitable tape such as kraft paper having one side coated with a hot melt adhesive. Also, the tape may be a plastic material having one side thereof adapted to be heat sealed after being folded over the end of the bag. The tape 19 is fed from a roll 19a over a roller 20 in between a pair of pressure rollers 21 where the tape is folded into a V shape and pressed over the open end of the bag 17, as may be seen in FIG. 2. The taped end of the bag then passes through a heat sealer assembly 22 which presses each side of the tape tightly to the opposing faces of the bag and heat seals the tape securely to the bag. A uitable type of heat sealer apparatus is disclosed in US. Patent 2,749,966. As seen in FIGS. 2 and 3, the individual bags are spaced apart thereby providing a pace over which the closure tape extends. The tape connected bags next pass through pressure rollers 23-23 which presses the folded tape firmly to the bag body over the line of stitching. The rollers also adhesively seal the portions of the tape extending between adjacent bags in a face to face relationship.

An alternate, and preferred way of applying the hot melt adhesive is to spray or flow a coating of molten adhesive from a storage tank onto either the tape or to the end portion of the bag prior to applying the tape to the bag end.

Bags next pass through the tape cutter-adhesive applicator portion of the apparatus designated as that portion within the bracket 4 seen in FIG. 1. Referring now to FIG. 4, the leading edge of each bag 17 will strike arm 24 of an electrical switch 25, which switch controls the action of the tape cutting knife 26 which is driven by a solenoid (not shown) or other suitable means. The arm 24 is positioned so that it raises up when the body of the bag has passed over the switch arm. When switch arm 24 raises, power is applied to knife 26 to make a cut in the tape 19 to separate the bags. If the space between adjacent bags is considerable, the apparatus may be designed to cut a section out of the tape to provide shorter tape tabs. This can be accomplished by providing a time delay mechanism which is actuated by the switch 25 whereby the knife 26 will make two successive cuts thereby cutting a short section out of the tape extending beween adjacent bags. After the tape is cut the individual bags are then provided with a trailing tab 27 and a leading tab 28 as seen in FIGS. 2 and 3.

This assembly may also be adjusted whereby the switch 25 controls the adhesive spray application 29. The applicator sprays a coating of adhesive over the upper surface of the trailing tab 27, then shuts off until the leading tab 28 is positioned underneath the nozzle 30, then the applicator 29 is actuated to spray the upper surface of the leading tab 28 with adhesive. The bags are then received on table 31 and moved to the next section of the apparatus.

The bags next move through the leading tab turner assembly, designated generally 32, as seen within the bracket 5 in FIG. 1. Bracket 33 supports rearward shaft 34 which has an arm 35 attached adjacent its end. The arm extends downwardly and its lower end 36 is upturned to prevent damage to the bags. The lower end 36 of the arm 35 has attached thereto a short rod 38 which rests in the depression 37 provided in the table 31.

Bracket 33 carries a forward shaft 39 having attached thereto a downwardly extending pressure foot 40. Pressure foot 40 is held in firm contact with table 31 by means of spring 41. As seen in FIG. 5F, the pressure foot 40 has extending outwardly therefrom a support member 42 which carries a cam 43 adapted to be engaged by the lug 44 on the chain conveyor.

The operation of the leading tab turner assembly will now be described with reference to FIGS. 5-5F. As seen in FIG. 5, the bag 17 moves from right to left over table 31. The lower end of the bag with tape 19 applied thereto moves forward until the leading edge of the bag strikes the arm 35. When the leading edge of the bag 17 is in first contact with the arm 35, the leading tab 28 projects over the recess 37 and rests on top of rod 38 as can be seen in FIGS. 5 and 5A. Referring now to FIG. 5B, as the leading edge of the bag 17 moves forward, this forces arm 35 to begin to raise up thereby elevating rod 38 which starts to bend the leading edge tab 28 back toward the face of the bag. As seen in FIG. 5C, when the leading edge of the bag 17 passes under the curved lower end 36 of arm 35 the rod 38 has folded tab 28 through an arc of about The lower end 36 of arm 35 then is lifted on to the top surface of the bag 17 just prior to the insertion of the leading edge of the bag under pressure foot 40. As seen in FIG. 5D, pressure foot 40 firmly presses the leading tab 28 against the face of the bag 17 and adhesively seals it thereto. As seen in FIG. 5E, the bag passes out from under the lower end 36 of arm 35, the rod 38 drops back into recess 37 to prepare for turning the leading tab on the rearwardly adjacent bag 17. As seen in FIGS. 5D and 5E, lug 44, carried by the conveyor chain (not shown) engages the rear edge of each bag and moves the bag forward over the table 31. As the trailing edge of the bag approaches the pressure foot 40, lug 44 contacts the angular forward face 45 of a cam 43. As seen in FIG. 5B the cam is lifted up by the lug 44- thereby raising the pressure foot 40 from the surface of the bag to permit the trailing tab 27 to pass underneath the pressure foot 40 while it is in the elevated position. This is necessary to prevent wiping off the adhesive which has been applied to the upper surface of the trailing tab 27. As the trailing tab 27 moves out from under the pressure foot the cam 43 disengages the lug 44 thereby allowing pressure foot 40 to recontact table 31 to prepare for pressing down the next succeeding leading tab.

The trailing tab turner assembly, designated generally 46, is that portion of the apparatus shown within the bracket 6 of FIG. 1. This assembly will now be described with reference to FIGS. 6-6B of the drawings. The bag 17 moves forward over the table 31 being pushed by lug 44 which abuts the trailing edge of the bag. As lug 44 reaches the position of the trailing tab turner assembly, designated generally by the numeral 46, it contacts a roller 47 mounted on arm 48 which is attached to shaft 49 at its upper end. The shaft 49 is rotatably mounted in bracket 50. Referring now additionlaly to FIGS. 6A and 6B, shaft 49 has attached to one end thereof a sector gear 51. In one embodiment the sector gear 51 has 94 teeth. The teeth of gear 51 mesh with the teeth of a lower sector gear 52 (which has 47 teeth in one embodiment). The gear 51 is fixedly mounted on rotatable shaft 53. Shaft 53 (see FIG. 6D) has fixedly attached at the other end thereof a support bracket 54 which carries a horizontally extending pin 55 at its outer end. As seen in FIG. 6, the pin 55 is received in the recess 56 provided in support table 31. As the bag passes over support table 31, the trailing tab 27 is positioned immediately above the pin 55 as the lug 44 engages roller 47. Lug 44 moves arm 48, rotating shaft 49 and sector gear 51 in a clockwise direction. Sector gear 52 then moves shaft 53 and attached arm 54 in a counterclockwise direction. As arm 54 rotates, attached pin 55 is lifted out of recess 56 and picks up the trailing tab 27 from the underside and folds it over the top of bag 17. When roller 47 passes over the top of lug 44, the sector gears swing back to the vertical position and return the arm 54 and the pin 55 to their original position as seen in FIG. 6 to await the next tape tab turning operation.

Lug 44 continues its forward movement and makes engagement with a clutch trip dog 57. As seen in FIGS. 6, 6B and 60, the clutch trip dog 57 is pivotally mounted on bracket 58 and engages at its upper end a spring loaded latch pin 59. Latch pin 59 engages a stud 59a received in an opening in rotatable shaft 61 and projects radially from the shaft. As seen in FIGS. 6B and 6C, the stud 59a releases rotatable shaft 61 which has its inner end connected to one portion of a one revolution sprag clutch mechanism, designated generally by the numeral 60. The other portion of the clutch mechanism is fixedly connected to a constantly rotating shaft 62. When stud 59a releases shaft 61, the shaft 61 is rotated one full turn by the shaft '62 through the clutch mechanism 60. The stud 59a strikes latch pin 59 after one turn of shaft 61 to stop the rotation of the shaft 61. The rotation of shaft 61 rotates drive sprocket 63 which is fixedly attached to shaft 61. A chain belt 64 passes over drive sprocket 63 and connects the two lower idler sprockets 65 and '66 thereto. A series of leaf springs 67 are attached to the drive chain 64 at opposite locations thereon. In the embodiment shown in FIG. 6B, three leaf springs are mounted at opposite positions on the drive chain. The purpose of the drive chain assembly and leaf springs is to firmly press the trailing tab against the face of the bag and insure that a vermin-proof seal is made on the fold line of this tab. As seen in FIG. 6B, the springs 67 each successively contact the turned down trailing tab 27 to press it firmly against the body of the bag 17. The leaf springs 67 travel in the same direction as the bag 17 but move at a speed about 2 /2 times the forward speed of the bag to provide the pressing action necessary to insure a good seal of the trailing tab 27 to the face of the bag 17. After the bag 17 passes out from under the drive chain '64, the clutch stops the drive chain in the position shown in FIG. 6. Thus, the leaf springs 67 are positioned out of contact with the table surface 31 to permit the next bag to pass underneath the assembly without initially contacting the leaf springs 67. A deflector 68 (see FIG. 6') is mounted on arm 69 and prevents the bag 17 from being pushed forward by leaf springs 67 when they make their wiping action.

The bags next pass through the pressure roll assembly, designated generally by the numeral 70, which is shown within the bracket 7 in FIG. 1. As seen in FIG. 7, a rubber covered lower pressure roll 71 is fixedly mounted on rotatable drive shaft '72 which is driven by means of sprocket 73 and chain 74 which is connected to a power means (not shown). Shaft 72 passes through a bearing assembly 75 mounted in support frame 76. Attached to the outwawrd end of shaft 72 is lower drive gear 77 which engages upper drive gear 78 that is attached to rotatable shaft 79. This shaft also passes through a bearing assembly 75 received in support frame 76 and has fixedly attached thereto a rubber covered upper pressure roll 80. These pressure rolls 71 and 80 press the tape 19 securely to the lower end of the bag 17 thereby insuring that the hot melt adhesive and adhesive holding the tabs to the face of the bag make a secure bond.

Referring now to FIG. 1, the conveyor chains (not shown) pass over drive roller 81 and convey the bags to the conveyor assembly, designated generally 82.

While the method and apparatus described hereinbefore calls for a sewn thread closure for the bottom of the bag, it is not necessary that the apparatus or the method utilize a sewn thread closure. In certain applications, the apparatus and method may be utilized whereby a hot melt adhesive is applied to the end of the bag and a tape folded thereover to provide a tight end closure for a bag. Also, while the invention has been described with particular reference to paper bags, the invention is not to be limited to such bags. The apparatus and method of the present invention are admirably suited to sealing the ends of single or multi-pl-y plastic bags.

It can be seen from the foregoing description that the present invention provides a method and apparatus for closing ends of bags whereby an insect-proof seal is effected. Additionally, no tabs extend outwardly from the sides of the bag which lessens the chance of breaking the insect-proof seal created by the present invention.

What is claimed is:

1. A method for sealing the ends of bags comprising: (a) conveying a plurality of bags, each having at least one flattened open end, arranged in side-by-side relationship in a direction parrallel to said open end; (b) continuously adhesively applying a strip of closure tape to said open end of said bag; (c) severing said tape between adjacent bags to provide a leading tape tab and a triling tape tab extending outwardly from the respective side edge of each adjacent bag; (d) applying a spray of adhesive from a spray nozzle to the upper surface of said leading tape tab; (e) interrupting said spray of adhesive as said bag passes underneath said spray nozzle; (f) applying a spray of adhesive from said spray nozzle to the upper surface of said trailing tape tab; (g) folding said leading tape tab backward and said trailing tape tab forward long a line coinciding with the side edges of said bag to bring said upper surface having the adhesive thereon into contact with said bag.

2. The method of claim 1 which includes the step of firmly pressing said tape tabs against said bag.

3. The method of claim 2 which includes the step of folding and pressing said leading tape tab firmly against said bag prior to folding and pressing said trailing tape tab firmly against said bag.

4. The method of claim 1 which includes the steps of providing a heat sealable adhesive betwene said strip of closure tape and said flattened bag end and heating said adhesive through said strip of closure tape to bond said tape to said bag.

5. The method of claim 4 which includes the step of applying a line of thread stitching across the flattened end of said bag in a position to be covered by said strip of closure tape prior to providing said heat scalable adhesive and applying said closure tape to the flattened end of said bag.

6. Apparatus for sealing the ends of bags comprising:

(a) means for conveying a series of bags;

(b) means for continuously applying a strip of closure tape to at least one flattened end of said bags;

(0) means for severing said tape between adjacent bags to provide a leading tape tab and a trailing tape tab extending outwardly from the respective side edge of each adjacent bag;

(d) means for applying an adhesive to one surface of said tape tabs; and

(e) means for turning said tape tabs back along a line coinciding with the side edges of each of said bags to secure said tape tabs to their respective bag.

7. The apparatus of claim 6 which includes means for pressing each tape tab firmly against its respective bag.

8. The apparatus of claim 7 which includes an assembly for pressing said trailing tape tab against said bag; said assembly including pressure applying means moving in the same direction as said bag and at a speed in excess of said bag speed.

9. The apparatus of claim 8 which includes means to 10. The apparatus of claim 6 which includes means for applying a line of thread stitching across the flattened end of said bag in a position to be covered by said strip of closure tape.

11. Apparatus for sealing the ends of bags comprising:

(a) a conveyor assembly including a chain drive having lugs thereon adapted to move a plurality of bags in side-by-side arrangement, each bag having at least one end closed by a line of thread stitching;

(b) a mechanism for applying a continuous strip of paper tape in the form of a V-fold over the sewn end of each bag, said tape having a heat sealable adhesive on the side contacting each bag;

(0) a heater assembly for heat sealing said tape to each of said bags;

(d) a knife assembly adapted to cut the tape between adjacent bags to provide a leading tape tab and a trailing tape tab on each bag;

(e) an adhesive applicator adapted to coat the upper surface of each said tape tabs with an adhesive; (f) a leading tab turner assembly including a pivoted arm having a pin extending from the lower end thereof adapted to engage the leading tab and to fold said tab back against said bag when actuated by the forward movement of said bag;

(g) a trailing tab turner assembly including,

(i) a pivoted arm having a pin extending from the upper end thereof adapted to engage the trailing tab and to fold said tab back against said bag when actuated by said lug on said chain drive of said conveyor, (ii) a sector gear device connected to said pivoted arm of (i) for actuation of said pivoted arm, (iii) a driven chain device having flexible fingers thereon adapted to press said trailing tab firmly against said bag, said device including a drive means having a one revolution clutch adapted to be actuated by said lug on said conveyor chain, and (h) a pair of opposed driven rollers adapted to firmly press said tape and said tabs firmly against said bag to effectively seal the end of said bag.

References Cited UNITED STATES PATENTS 1,955,310 4/1934 Powell et al. 229-62 XR 2,051,106 8/1936 Rosen 22962 2,197,490 4/1940 Williams et al. 229-62 2,423,080 7/1947 Belcher et al. 112-11 2,749,966 6/1956 Roetger 156-201 2,970,634 2/ 1961 Hantscho 15620 2 3,190,539 6/1965 Pyle et al 22962 EARL M. BERGERT, Primary Examiner.

G. M. MOXON II, Assistant Examiner.

U.S. Cl. X.R.

Images