US3585095A - System for producing grommet bags - Google Patents

Abstract

AN APPARATUS FOR FORMING GROMMET BAGS WHEREIN GROMMETS ARE HEAT SEALED TO BAG MATERIAL BY MEANS OF A PAIR OF MOVABLE TOOLS, ONE OF WHICH INCLUDES A MOVABLE PIERCING ELEMENT WHEREBY THE TOOLS ARE ADAPTED TO SUBSTANTIALLY SIMULTANEOUSLY FORM OPENINGS IN THE GROMMETS AND BAG MATERIAL DURING APPLICATION OF THE GROMMETS TO THE BAG. DRIVE MEANS FOR THE TOOLS COMPRISE A FIRST PNEUMATIC CYLINDER FOR DRIVING THE OPPOSED TOOLS AND A SEC-

OND PNEUMATIC CYLINDER FOR OPERATING THE PIERCING ELEMENT INDEPENDENTLY OF THE TOOL DRIVING MEANS. ELECTRICALLY OPERATED VALVES ARE ASSOCIATED WITH THE RESPECTIVE PNEUMATIC CYLINDERS, AND SWITCHING CONTROLS FOR THE VALVES ARE OPERATIVELY CONNECTED TO THE DRIVE MEANS EMPLOYED FOR MOVING BAG MATERIAL THROUGH THE APPARATUS.

Description

June 1971 G. E. SHEARIHOD 3,

SYSTEM'FOR PRODUCING GROMMET BAGS Filed July 11. 1968 3 Sheets-Sheet 1 Gear e 58/26 #2042 by Q.

June 1.971 s. E. SHEARHOD 95 SYSTEM FOR PRODUCING GROMMET BAGS Filed July ll, 1968 s Sheets-Sheet z June 1971 s. E. SHEARHOD 3.585.095

SYSTEM FOR PRODUCING GROMMET BAGS Filed July 11, 1968 3 Sheets-Shoot, :5

FIG: 10

Sup 1 1078 United States Patent 3,585,095 SYSTEM FOR PRODUCING GROMMET BAGS George E. Shearhod, Holfman Estates, Ill., assignor to Vision Wrap Industries, Inc., Schiller Park, Ill. Filed July 11, 1968, Ser. No. 744,142 Int. Cl. B32h 31/10, 31/18; B2611 /20 US. Cl. 156-513 Claims ABSTRACT OF THE DISCLOSURE An apparatus for forming grommet bags wherein grommets are heat sealed to bag material by means of a pair of movable tools, one of which includes a movable piercing element whereby the tools are adapted to substantially simultaneously form openings in the grommets and bag material during application of the grommets to the bag. Drive means for the tools comprise a first pneumatic cylinder for driving the opposed tools and a second pneumatic cylinder for operating the piercing element independently of the tool driving means. Electrically operated valves are associated with the respective pneumatic cylinders, and switching controls for the valves are operatively connected to the drive means employed for moving bag material through the apparatus.

This invention relates to a system for the manufacture of bags adapted to hold a wide variety of materials under a wide variety of conditions. The invention is particularly concerned with the production of bags or similar containers which are formed of polyethylene or equivalent materials and \which are provided with grommets 'whereby the bags can be effectively employed for rack merchandising and for similar uses.

It is an established fact that the cost of packaging must be taken into consideration in determining profit which can be made in the merchandising of bags. It is, therefore, highly important in the packaging industry to provide bags and other containers which can be economically manufactured. It is also important to provide bags which are capable of retaining the items therein over indefinite periods without danger of breaking or tearing of the bags. Finally, it is an important consideration in the packaging industry to provide bags which do not detract from or which increase the sales appeal of articles contained therein.

Use has been made of polyethylene bags due to the fact that these bags have many desirable characteristics. Specifically, polyethylene is a relatively inexpensive material, it is relatively strong, and in most instances, articles can be safely stored therein. Furthermore, the bags can be easily printed upon and the transparent nature of the polyethylene enables purchasers to view the contents, and, therefore, such bags are desirable from a sales appeal standpoint.

In many instances, it is desirable to provide bags which are suitable for rack merchandising. Specifically, merchants are interested in displaying goods on racks in order to make maximum use of available space and in order to locate the goods where they can be easily reached by the public. Where polyethylene bags have been employed for such rack merchandising, ditliculties have been encountered due to the fact that the polyethylene tends to tear once holes are punched therein or when any metal members are attached thereto. Fracturing may be caused by gauge variations in the polyethylene or when non-concentric metal grommets of the type which are deformed during application are encountered.

Grommet bags of the general type manufactured in accordance with this invention are described in Brieske Patent Nos. 3,208,660 and 3,256,127. Brieske et al. appli- ICC cation Ser. No. 427,773 describes an apparatus and method highly suitable for the production of such bags. It will be understood that although specific mention has been made of polyethylene, other materials compatible with the operations described herein are contemplated.

It is a general object of this invention to provide a system for the production of grommet bags of the type described, which system is characterized by various substantial improvements from the standpoint of operating efficiency, particularly when compared with the system described in the above mentioned application.

It is a further object of this invention to provide a system of the type described which is particularly characterized by operating mechanisms which can be easily adjusted to provide variations in production results, which will operate reliably for long periods of time, and which can be installed and maintained with relative ease.

These and other objects of this invention will appear hereinafter and for purposes of illustration, but not of limitation, specific embodiments of this invention are shown in the accompanying drawings wherein:

FIG. 1 is a rear elevational view of the structure employed in the manufacture of the bags of this invention;

FIG. 2 is an enlarged cross-sectional view taken about the line 22 of FIG. 1;

FIG. 3 is a detail fragmentary view of the grommet forming tape with the grommet forming portion removed;

FIG. 4 is a detail view of the grommet forming portion before piercing;

FIG. 5 is a detailed, fragmentary view of a grommet in association with a bag;

FIG. 6 is a side elevational view of the structure;

FIG. 7 is an enlarged cross-sectional view illustrating the grommet piercing operation;

FIG. 8 is a fragmentary view taken about the line 88 of FIG. 6;

FIG. 9 is a cross-sectional view taken about the line 99 of FIG. 6; and,

FIG. 10 is a schematic illustration of the pneumatic circuitry of the system.

The system of this invention generally involves the provision of a heat sealable material, such as polyethylene, for the formation of an enclosure defining a bag. A pair of grommet forming members are positioned adjacent one edge of the material and on opposite sides thereof. Thereafter, heated tools are applied to provide for heat sealing of the members to the material, and these tools include means for piercing the grommet forming members whereby openings are formed substantially simultaneously with the application of the members to the material.

An apparatus of the type described in application Ser. No. 427,773, now Pat. No. 3,392,077, is highly suitable for carrying out the method and for producing the novel bags. This apparatus is adapted to apply the grommets in a continuous operation to thereby permit forming of bags in an extremely rapid and efficient operation while maintaining high quality standards.

In the drawings, the bag material is designated by the numeral 10 in FIGS. 1, 6 and 7. As disclosed in the aforementioned application, the grommets are preferably applied adjacent one edge of the sheet 10, this sheet usually being a double ply of heat scalable material.

A supply of grommet forming material is provided in the form of strips 12 fed from rolls 14. These rolls are supported on arms 16 which are attached to the frame of the apparatus.

The grommet applying operation can best be understood when considering FIGS. 3 through 7. The sheet 10 of bag forming material is fed between platens 18 and 20.

The strips of grommet forming material 12 are fed to grooved tracks 22 which are located on the outer surfaces of the platens. Plates 24 are provided on the platens for confining the strip of tape in the tracks.

A first tool 26 is adapted to be driven downwardly into the opening 28 defined by the platen 18. A second tool 30 is adapted to be driven upwardly into an opening 32 defined by the platen 20. When these tools enter the respective openings in the platen, they operate to cut a circular piece 34 from the respective strips of grommet forming material (see FIGS. 3 and 4).

The tool 26 carries a piercing element 36 while the tool 30 defines a bore 38 dimensioned to receive the piercing element. As explained in the aforementioned application, the tools 26 and 30 operate to force the circular pieces 34 into engagement with the bag material 10, and since at least one, and preferably both of the tools are heated, heat sealing of the pieces 34 to the bag material will result. At the same time, separate drive means are employed for driving the piercing element 36 completely through the pieces 34 and the bag material whereby a hole will be formed through the assembly. The tools are then withdrawn, and the bag material and grommet forming material are both indexed so that upon the return stroke of the tools, a new grommet applying operation will take place.

The piercing element 36 is provided with a cylindrical curvature which has been formed to increase the useful operating period for the tool. Thus, there is a tendency for the center portion of the grommet forming material and bag material to adhere to the piercing element after this material is removed. This tendency is particularly apparent when the cutting edges of the tool are dulled, and the provision of the cylindrical curve illustrated avoids this problem for a substantial period of time. In referring to a cylindrical curve, it will be understood that the curvature is that which can be achieved by placing the flat end of the piercing element against a cylindrical grinding tool. The curvature does not correspond with a section of a sphere.

A further and primary concern of the invention relates to the drive mechanisms employed for reciprocating the tools 26 and 30 and the piercing element 36. In addition, the invention is concerned with improved means for withdrawing and disposing of scrap from the strips 12 of grommet forming material.

Referring primarily to FIGS. 1 and 6, it will be seen that the tool 26 comprises an elongated cylinder having a spool 40 at its upper end. A drive arm 42 is connected at one end to the spool 40, and at the other end to rocker shaft 44. A second arm 46 is connected at one end to this shaft. The other end 48 of the arm 46 defines an opening having a connecting pin 50 received therein.

The tool 26 is movable within a suitable bore defined in the frame section 52 of the apparatus. The rocker shaft 44 and a similar rocker shaft 54 are also supported by this frame. An arm 56 is connected at one end to the shaft 54, and is provided with a bifurcated end 58 which fits around the pin 50. A second arm 60 extends from the shaft 54, and a link 62 connects this arm to the bottom end of the tool 30. As explained in the aforementioned ap plication, the link 62 is provided with a resilient connection with the arm 60 to prevent the ends of the tools 26 and 30 from exerting undue pressure on each other.

A lever 64 defines a bifurcated end 66 which fits around the pin 50. The other arm of the lever is connected at 68 to the piston 70 of pneumatic cylinder 72. The piston 70 is shown in the extended position which causes the lever 64 to hold the arms 46 and 56 in an inner position. This turns the shafts 44 and 54 so that the arms 42 and 60 will locate the tools 26 and 30 in the retracted position. Upon the return stroke of the piston 70, the lever 64 will cause arms 46 and 56 to move outwardly thereby rocking the shafts 44 and 54, whereby the tools 26 and 30 will move together for the grommet applying operation.

A second pneumatic cylinder 76 is provided with a piston 78 which is connected at 80 to the upper end of the piercing element 36. A bracket 82 is mounted on the arm 42, and the cylinder 76 is carried by this bracket. Accordingly, the cylinder and associated piston will move in conjunction with the arm 42 so that the piercing operation can be undertaken when the tool 26 has moved into grommet applying position.

The means for handling the strips 12 of a grommet applying material are best illustrated in FIGS. 2 and 6 through 9. The strips are moved from the rolls 14, which are idler rolls, and then past the platens 18 and 20 over guide roll 86 where they are joined together. At this time, the strips have a configuration as shown in FIG. 3 since the circular portions 34 have been removed.

The pair of strips moves downwardly between rubber draw rolls 88. A pinion 90 is secured to the shaft of one roll, and a rack 92 is operatively engaged with the pinion. The piston 94 of pneumatic cylinder 96 also serves to reciprocate the rack. An over-running clutch 98 is provided at the opposite ends of the shaft for the driven roll 88 so that this roll will only turn on the extending stroke of the piston. Thus, the clutch operates to prevent rotation of the roll during the return stroke of the piston. A gear 100 meshes with gear 102 carried by the shaft of the other roller 88 so that both rollers will be positively driven.

A pair of guide wires 104 extend between the rolls 88 and are received within grooves 106 defined by these rolls. The guide wires extend beyond the rolls into a chute 108 which receives the tape as the tape passes from the rolls. The wires serve to guide the tape through the rolls and into the chute.

A pivotally mounted knife 112 is located at the end of the chute. The knife passes immediately adjacent the bottom edge of the plate This plate and bar 114 serve as a stationary blade edge whereby the tape is chopped into pieces. The knife 112 is pivotally connected at 116, and the end 118 of the knife is attached to a piston 120 which is operated by the cylinder 122.

As will be explained, the cylinder 122 can be controlled by the drive mechanisms for moving bag material through the apparatus. The chopping action achieved provides distinct advantages over collecting the scrap in the form of a continuous strip. This strip tends to build up quite rapidly, and presents a significant problem from a cleanliness and maintenance standpoint. When the material is chopped into pieces, it is much more easily handled for disposal purposes. As shown in FIG. 1, the pieces of scrap do not have to be regular in size. Thus, the control means for the knife 112 do not have to be in any precise position.

FIG. 10 illustrates schematically the control system for the construction of this invention. The system involves the use of a cam shaft which is represented by the line 124. This shaft can be attached to a sprocket 126 or any other drive means which is directly connected to the main drive which provides for transporting of the bag material through the apparatus.

A plurality of cams 128, 130, 132 and 134 are attached to the shaft 124. Micro switches 136, 138, and 142 are operatively associated with the respective cams.

The cam 128 and micro switch 136 are connected to solenoid valve 144. A line 146 connects the solenoid valve with a source of compressed air 148. A pressure relief valve 150 is included in the line 146.

The valve 144 is connected through line 152 to the pneumatic cylinder 122 which operates the knife 112. A second line 154 serves as a return line from the cylinder 122. An extension 156 of the line 154 is connected to the pneumatic cylinder 96 which controls the rack 92 and pinion 94 for driving rolls 88. An extension 158 of the line 152 serves as a return line from the cylinder 96. Flow control valves 160 may be included in each line if desired.

The switch 136 and associated solenoid valve 144 controls the operation of the drive rolls 88 and the knife 112. When the solenoid is energized, pressurized air is passed through line 154 and line 156 to drive the piston 94 to the extended position whereby the rolls '88. will operate to withdraw scrap tape. When the solenoid is de-energized the pressurized air is passed through line 15 2 which operates to extend the piston 120 so that chopping action will take place. The pressurized air continues through line 158 whereby the piston 94- will be forced back. Similarly, the return movement of the knife 112 will take place when the solenoid is again energized. In this way, a single solenoid valve operates both the scrap drive rolls and the chopping knife, and the operation insures that the scrap will be stationary during the chopping operation while the knife will be out of position during movement of the scrap by the knife rolls.

The connection of the pneumatic cylinder 96 in the manner shown provides for relatively smooth withdrawal of the scrap tape. Thus, the two-way pneumatic arrangement results in gradual movement of the piston 94 during its forward stroke rather than extremely rapid movement so that the tape will move relatively slowly. It has been found that rapidly operating drive rolls tend to snap the tape, and this, of course, would require shutdown of the equipment.

The cam 130 and associated switch 138 are connected to solenoid valve 162 which receives pressurized air through line 164 and pressure relief valve 166. Lines 168 and 170 are provided for delivering and returning pressurized air to the pneumatic cylinder 76 to provide for operation of the piercing element 36 as the solenoid valve is energized and de-energized.

The cams 132 and 13 4 operate micro switches 140 and 142, respectively. These micro switches have a common lead wire 171 connected to a double acting solenoid valve 172. The valve 172 is supplied with pressurized air through line 164. When the valve 172 is in one position, the pressurized air will force the piston 70 of the pneumatic cylinder 72 downwardly which will cause the tools 26 and 30* to move apart in response to the action of lever 64. When the valve position is shifted, the pressurized air will be fed from line 17 4 to provide a retracting stroke for the piston 70 thereby moving the tools together for achieving the grommet forming operation.

Both the forward and retracting movement of the piston 70 are positively controlled in accordance with the preferred form of the invention. Thus, closing of the micro switch 142 will energize the solenoid 172 to drive the piston 70 during the extending stroke while closing of the switch 140 energizes the solenoid to provide the return stroke.

The positive drive which is provided for both the extending and retracting stroke of the piston 70 is of major importance. Thus, it has been found that the most eifective application of grommets requires a relatively critical relationship between the tools employed. One major factor is the dwell time of the tools when they are in the closed position. At this time, sufficient pressure and heat must be applied by the tools to insure proper attachment of the grommets while at the same time, avoiding damage to the bag material, for example by over-heating.

Where grommet materials of different physical characteristics, such as heat transfer ability, or different thicknesses are employed for different operations, then adjustments in the tools are acquired to achieve the most efficient operation. With the construction of this invention, adjustment of the relationship between the operating tools can be completely conrolled by adjusting cams 132 and 134 on the cam shaft. Thus, these cams are the sole means employed for determining the timing of the tool operations, and adjustments can be easily made, for example, by attaching the cams to the cam shaft through the use of set screws.

Since the cams only engage the micro switches, very little wear will result thereby greatly increasing reliability.

This represents a substantial improvement over the system described in the aforementioned application where the cams employed provide the force necessary for driving the various tools. As the engaging surfaces became worn, the conditions of grommet application varied so that consistent operation over long periods of time was not possible.

It will be understood that various changes and modifications may be made in the above described construction which provide the characteristics of this invention without departing from the spirit thereof, particularly as defined in the following claims.

I claim:

1. In an apparatus for forming grommet bags wherein the grommets comprise a pair of substantially flat members fixed on opposite sides of said bags with aligned openings defined by each of said members and by said bag, and wherein the grommets are adapted to be heat sealed to the bag by means of a pair of movable grommet applying tools, said heat sealing being accomplished by providing means for transporting bag forming material through the apparatus and by simultaneously disposing bag forming material and grommet forming material between said tools, heating at least one tool and driving said tools together, one of said tools carrying a piercing element for forming said openings and the other tool defining a bore for receiving the piercing element whereby the tools are adapted to substantially simultaneously form said openings while applying said grommet forming material to said bag forming material, the improvement in drive means for said tools comprising a first pneumatic cylinder having the piston thereof connected to a lever, the reciprocation of the piston of said first cylinder impartingpivotal movement to said lever, a pair of rocker means each having one end connected to said tools, an arm of said lever being connected at the other end of said rocker means for thereby driving said tools toward and away from each other in response to operation of said first cylinder, a second pneumatic cylinder having the piston thereof operatively connected to said piercing element for driving said piercing element independent 1y of said tools, said second pneumatic cylinder being supported by the tool carrying said piercing element whereby said second cylinder is moved along with said tool during operation of said first pneumatic cylinder, electrically operated valve means associated with each pneumatic cylinder, and electrical control means for said valve means, said control means being operatively connected to means for transporting said bag forming material through the apparatus whereby the operation of said tools and said piercing element is directly synchronized with the movement of said bag forming material.

2. An apparatus in accordance with claim 1 wherein said switches comprise micro switches, a cam shaft tied to said transporting means, and adjustable cams on said shaft for operating said switches whereby the timing of the operation of one valve can be adjusted relative to the other valve.

3. An apparatus in accordance with claim 1 wherein the valve means associated with said first pneumatic cylinder comprise first and second valves operated by separate electrical switch means whereby the movement of said tools toward each other is controlled by one switch means and the movement of the tools away from each other is controlled by the other switch means.

4. An apparatus in accordance with claim 1 wherein said grommet forming material is provided in the form of a continuous tape and wherein pieces of the tape are removed to form the grommets thereby leaving a continuous strip of scrap material, withdrawal rolls for said scrap and chopping means beyond said rolls for chopping said scrap into small pieces.

5. An apparatus in accordance with claim 4 wherein said chopping means include a pivotally mounted knife, and a third pneumatic cylinder having its piston attached to said knife for pivoting said knife, and wherein said third pneumatic cylinder is controlled by means of the mechanisms transporting said bag forming material through said apparatus.

6. An apparatus in accordance with claim 4 including third and fourth pneumatic cylinders for respectively operating said withdrawal rolls and said chopping means, and including a valve control means connected to said third and fourth pneumatic cylinders, said control means providing for operation of said chopping means when said withdrawal rolls are stationary and providing for operation of said withdrawal rolls when said chopping means have been moved out of chopping position.

7. In an apparatus for forming grommet bags wherein the grommets comprise a pair of substantially flat members fixed on opposite sides of said bags with aligned openings defined by each of said members and by said bag, and wherein the grommets are adapted to be heat sealed to the bag by means of a pair of movable grommet applying tools, said heat sealing being accomplished by providing means for transporting bag forming material through the apparatus and by simultaneously disposing bag forming material and grommet forming material between said tools, heating at least one tool and driving said tools together, one of said tools carrying a piercing element for forming said openings and the other tool defining a bore for receiving the piercing element whereby the tools are adapted to substantially simultaneously form said openings while applying said grommet forming material to said bag forming material, the improvement in drive means for said tools comprising a first pneumatic cylinder having the piston thereof operatively connected to said tools for driving said tools toward and away from each other, a second pneumatic cylinder having a piston thereof operatively connected to said piercing element for driving said piercing element independently of said tools, electrically operated valve means associated with each pneumatic cylinder, electrical control for said valve means, said control means being operatively connected to means for transporting said bag forming material through the apparatus whereby the operation of said tools and said piercing element is directly synchronized with the movement of said bag forming material, and wherein said grommet forming material is provided in the form of a continuous tape with pieces of the tape being removed to form the grommets thereby leaving a continuous strip of scrap material, withdrawal rolls for said scrap, chopping means beyond said rolls for chopping said scrap into small pieces, said chopping means including a pivotally mounted knife, and a third pneumatic cylinder having its piston attached to said knife for pivoting said knife, and wherein said third pneumatic cylinder is controlled by means of the mechanisms transporting said bag forming material through said apparatus.

8. An apparatus in accordance with claim 7 wherein a pinion is operatively connected to one of said drive rolls, a rack for rotating said pinion, a fourth pneumatic cylinder having its piston attached to said rack, and oneway clutch means associated with said pinion whereby said withdrawal rolls rotate only during movement of the rack in one direction.

9. In an apparatus for forming grommet bags wherein the grommets comprise a pair of substantially flat members fixed on opposite sides of said bags with aligned openings defined by each of said members and by said bag, and wherein the grommets are adapted to be heat sealed to the bag by means of a pair of movable grommet applying tools, said heat sealing being accomplished by providing means for transporting bag forming material through the apparatus and by simultaneously disposing bag forming material and grommet forming material between said tools, heating at least one tool and driving said tools together, one of said tools carrying a piercing element for forming said openings and the other tool defining a bore for receiving the piercing element whereby the tools are adapted to substantially simultaneously form said openings while applying said grommet forming material to said bag forming material, the improvement in drive means for said tools comprising a first pneumatic cylinder having the piston thereof operatively connected to said tools for driving said tools toward and away from each other, a second pneumatic cylinder having the piston thereof operatively connected to said piercing element for driving said piercing element independently of said tools, electrically operated valve means associated with each pneumatic cylinder, electrical control for said valve means, said control means being operatively connected to means for transporting said bag forming material through the apparatus whereby the operation of said tools and said piercing element is directly synchronized with the movement of said bag forming material, third and fourth pneumatic cylinders for respectively operating said withdrawal rolls and said chopping means, and including a valve control means connected to said third and fourth pneumatic cylinders, said control means providing for operation of said chopping means when said withdrawal rolls are stationary and providing for operation of said withdrawal rolls when said chopping means have been moved out of chopping position.

10. An apparatus in accordance with claim 9 wherein said second pneumatic cylinder is supported by the tool carrying said piercing element whereby said second cylinder is moved along with said tool due to the operation of said first pneumatic cylinder.

References Cited UNITED STATES PATENTS 2,033,553 3/1936 Scholl l56261 3,352,737 11/1967 Jordan 156-514 3,392,077 7/1968 Brieske et a1 1565l3X SAMUEL W. ENGLE, Primary Examiner J. M. HANLEY, Assistant Examiner US. Cl. X.R.

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