High-Capacity, High-Speed Bag Loading and Sealing System

Abstract

A bag loading and sealing system and method in which a continuous web of bags is continuously moved along a line. The web of bags is slit open to expose the interior of the bags and the bags of the web are separated from each other by a rod engaging perforated lines of separation between the bags. The open tops of the bags define a pair of flaps, each of which is gripped by a gripping chain, the paths of which diverge to form a mouth at the top of the bag. Material is deposited into the bag through the mouth and the gripper chains then converge to close the bag. The bags are transferred to gripper belts, with the top edge of the bag being slit off between the belts and the bags being transported through a hot air sealer where the remaining portions of the top of the bags are melted and fused together. A spool-type take-up winder is provided to retrieve the portion of the bags trimmed from the tops thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of pending provisional application Ser. No. 61/719,000, filed Oct. 26, 2012, by the same title, which is fully incorporated herein by reference.

TECHNICAL FIELD

The present invention pertains generally to automated packaging and more specifically to automated machinery for opening, inserting product into and sealing a continuous series of bags such as polyethylene bags at a very high rate.

BACKGROUND ART

Automated packaging devices and machines that package various items into polymer-based bags are limited in the number of bags that can be filled at one time or in a single cycle, the amount of weight that each bag can carry in the filling process, and the ability to adjust to accommodate bags of different sizes. Sealing of bags in a continuous operation is typically done as a separate operation which is a serious impediment to speed and total packaging production rate.

There is a need in the art for a bag loading and sealing system that can operate at high speeds with a continuous web of bags, opening the bags, accommodate filling of the bags, and sealing and separating the bags from each other and the web in a continuous fashion without a need for starting, stopping and indexing the movement of the web of bags along the processing line.

SUMMARY OF THE INVENTION

In light of the foregoing, it is a first aspect of the invention to provide a bag loading and sealing system that runs a continuous web of interconnected bags.

Another aspect of the invention is the provision of a bag loading and sealing system that sequentially opens the bags and substantially separates them from each other prior to filling.

Yet a further aspect of the invention is the provision of a bag loading and sealing system that opens the bags with an adjustable gripper chain that is adapted for adjustment to accommodate bags of various sizes.

Still a further aspect of the invention is the provision of a bag loading and sealing system that opens the bags wide, with a substantially rectangular mouth for ease of filling.

An additional aspect of the invention is the provision of a bag loading and sealing system that seals the bags with blown hot air to accommodate continuous transport through the sealing mechanism.

Yet another aspect of the invention is the provision of a bag loading and sealing system that employs a take-up winder for uniformly winding onto a spool a portion of the web of bags trimmed during the transporting and sealing operation.

Still a further aspect of the invention is the provision of a bag loading and sealing system that is continuous in operation, reliable in performance, and conducive to implementation with state of the art components.

In one embodiment, the high speed high capacity bag loading and sealing system of the present disclosure utilizes a continuous roll of tubular form polyethylene material or the like, separable in pre-defined sections to define a continuous series of individual bags, opens each bag at one end and establishes registration of the location of each bag in the series, grips and spreads the opposing edges of the upper peripheral end of each opened bag for conveyance along a fill path by dual path gripper chains; the gripper chains transferring filled bags to a pair of opposing transfer belts to transfer each bag from the gripper chain to the transfer belts, the transfer belts interfaced with opposing sealer belts for transfer of each bag from the transfer belts to the sealer belts upon trimming of the opposing edges of the upper peripheral end of each bag with the opposing edges of the upper end of each bag in a closed state, the sealer belts operative to carry each bag to at least one sealing apparatus, the sealer belts and sealer operable continuously and independent of the operation of the gripper chains and transfer belts.

The system can accommodate bags of many different sizes, different material and material weight, and substantially higher bag content weight by the utilization of gripper chains. The amount of excess material which constitutes the continuous strip at the top of the series of bags is significantly reduced by trimming closely proximate to the gripping region of the gripper chains. Mechanical and/or optical sensing of the precise location of each bag assures registration of the bags with the system throughout the operation. The system can operate at high speeds relative to prior art bag filling equipment, such as at least 100 feet per minute or 200 bags per minute or greater. And the bags can be advanced through the filling station continuously or intermittently, or the filling operation stopped entirely without affecting operation of the sealer.

DESCRIPTION OF DRAWINGS

For a complete understanding of the various aspect of an embodiment of the invention, reference should be had to the following detailed description and accompanying drawings wherein:

FIG. 1 is a schematic side elevational view of a bag loading and sealing system made according to the invention;

FIG. 2 is an illustration of a web of bags adapted for use with the bag loading and sealing system of FIG. 1;

FIG. 3 is an illustrative view of the station of the invention for slitting a tubular web of bags open;

FIG. 4 shows an alternative registration device from that employed in the embodiment of FIG. 3;

FIG. 5 is an illustrative view of the perforation separator used with an embodiment of the invention;

FIG. 6 is a top plan view of the station for slitting the bags open, with the cover removed;

FIG. 7 shows the exit end of the conveyor, with the transfer region and heat sealer next in line;

FIG. 8 shows the drive assembly for the gripper chain, absent the gripper chain sprocket;

FIG. 9 shows the assembly of FIG. 8 with the chain sprockets in place;

FIG. 10 shows the gripper belt assembly of an embodiment of the invention;

FIG. 11 shows the heat sealer of the invention in association with an illustration of the gripper belt and heater belt transfer; and

FIG. 12 is an illustration of the trip winder of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings and more particularly FIG. 1, it can be seen that a bag loading and sealing system made in accordance with an embodiment of the invention is designated generally by the numeral 10. A roll of bags 12 is shown in association with a turn bar 14 to introduce a web of interconnected bags to the mechanism for opening, filling and sealing them. It will be appreciated that while a roll of bags 12 may be employed, it is also within the scope of the invention to employ a box of fan-folded bags or the like. The web of interconnected bags is passed to a first station 16 for slitting the bags open, partially separating the bags of the web from each other, and gripping the open top edges of the bags to transport them through a filling station 18, with the bags having a substantially rectangular opening. Positioned beneath the transport and filling section 18 is a support conveyor 20, which may be employed to support the bottom of the bags of the transported web through the filling station and, most particularly, through the sealing mechanism to be described below. The support conveyor ensures that the bags, once filled, are maintained for transport by the gripper chain or gripper belts, as the case may be. At a transfer region 22, the web of bags is transferred from a gripper chain to a first gripper belt and then subsequently to a second gripper belt as will be discussed below. A control box 24, for controlling the motion of the conveyor 20, chain and belt drives, and the like is provided as at 24. The control box 24 may comprise a dedicated microprocessor or the like, receiving signals from photodetectors and the like later described, and accordingly controlling the movement of the web of bags along the assembly and in appropriate registration. The sealer system 26 is a hot air system, as will be described herein, but other various types of sealers, such as hot rollers and the like are also contemplated. Finally, a trim winder 28 is provided for retrieving trimmed material from the top of the web of bags that is trimmed off just prior to sealing.

With reference now to FIG. 2, an appreciation can be obtained as to the nature of a web or chain of bags 30 that may be maintained as the roll of bags 12. The web or chain of bags 30 is typically of a continuous tubular nature, as will be appreciated by those skilled in the art. The web 30 comprises a series of interconnected bags 32, the bags 32 being defined by vertical seals 34 spaced along the tubular web 30. The vertical seals 34 stop short of the top of the web 30, leaving a top strip 36 of a substantially continuous tubular nature existing thereabove. A line of perforations 38 extends between each of the vertical seals 34 to allow separation of the bags 32 from the web. The perforated line terminates at a horizontal cut or slit 40 that passes through the bottom edge of the top strip 36 where the perforated line 38 terminates. These short-length cuts or slits 40 accommodate opening of the bags 32 with substantially square ends, providing for substantially rectangular openings, as will be readily appreciated. A seal region 42 is defined beneath the slits 40 and the top strip 36. This seal region will eventually be sealed by a hot air sealer or the like as will become apparent below.

Also included as part and parcel of the web of bags 30 are a series of markers used in association with an optical sensor as will become apparent to allow for registration and control of the movement of bags through the system and particularly the separation of the bags 32 from each other by tearing of the perforation lines 38. The markers 46 are uniformly placed along the web 30, and are shown by way of example as being placed in association with the perforation lines 38, although any consistent spacing of the marker can be employed.

With reference now to FIG. 3, an appreciation can be obtained with regard to certain of the structure and features of the station 16 where slitting the bags open can be attained. As shown, a bag finger 48 extends horizontally in communication with the turn bar 14 and is adapted to receive the tubular top strip 36 of the web 30 thereon. The top edge 40 is centrally positioned on the bag finger 48. The web 30 is drawn under a guide roller 50 and into a slitting blade 52 that slits the top edge 44 of the tubular top strip 36 to open the bags 32. Cam sprockets 54 are positioned immediately downstream of the slitter blade 52, each having an associated gripper chain (not shown) thereon. Such gripper chains are well known in the art and are opened by the cam sprocket such that each gripper link opens and closes upon an associated one of the two top strips 36 that result from the slitting blade 52 slitting the top edge 44. Thereafter, the web of bags 30 is transported by the gripper chain along the processing line.

Also presented in association with the slitting blade 52 is a photodetector housing 56 mounted to the support block 58 for the guide roller 50. A photodetector 60 is maintained by the housing 56 and is exposed to monitor the top strips 36 of the web of bags 30. The photodetector detects the markers 46 uniformly spaced along the web of bags 30 and thereby provides a means for facilitating the timing of the opening and separating of the bags as they move along the processing line.

In FIG. 4, there is an illustration of an alternative system for assuring registration of the web of bags, the same being designated by the numeral 62. Here, a pin 64 is positioned to enter the open bag 32 once the top strip 36 has been slit, and to drop down into the bag, opening the bag as it travels under control of the gripper chain. At the sealed trailing end 34 of the bag, the pin 64 is engaged by the seal and rotates a support rod 66. The support rod 66 has a blade or vane (not shown) on an end thereof that rotates past a photodetector 68, causing the photodetector 68 to emit a signal corresponding to the trailing sealed edge of each bag. The photodetector 68 indicates the end of the bag for registration purposes. It also activates an air cylinder 70 that lifts the assembly of 64, 66, 68 upwardly, lifting the pin 64 from the bag to be returned into the next succeeding bag for the process to renew.

With reference now to FIG. 5, it can be seen that a perforation separator made and employed in the context of the invention is designated generally by the numeral 72. As shown, the perforation separator 72 is mounted by means of a mounting flange 74 at the station 16 as shown in FIG. 1, and adjacent to the web of bags 30. The perforator-separator 72 has a pair of opening pins 76 uniformly spaced upon a drive belt 78 mounted on sprockets 80. One of the sprockets 80 is selectively driven by a servomotor or the like 82, the timing of the actuation of which is timed off of the photodetector 60 through the controller of the control box 24. The servomotor 82 causes a half rotation of the belt 78, with an associated pin 76 passing through a slot 84 in the plate 86. The slot 84 provides guidance and lateral support to the pin 76.

In operation, the controller of the control box 24 determines from the signal generated by the photodetector 60 sensing the marker 46 when the servomotor 82 is to be actuated such that a pin 76 can engage the next perforated line 38. The pins 76 travel in a path perpendicular to the path of movement of the web 30 and are of such length and positioning to engage the perforated line 38 at the top thereof at or near the slit 40 and to pass downwardly to completely separate the bags 32 from each other at the perforated line. This occurs sequentially for each perforated line 38 of the bag. Accordingly, the bags 32 are opened at the top and separated from each other but for the continuous top strips 36, which are engaged and transported by the opposed gripper chains.

FIG. 6 shows the station 16 with the top cover removed to better appreciate the structure therein. As shown, the cam sprockets 54 rotate oppositely as designated by the arrows 90. As they rotate, they open and allow to close the gripping links of a pair of gripper chains, one associated with each sprocket. As stated above, the gripper links engage associated top strips 36 of the web of bags and move the bags through a channel 92 defined between a pair of plates. The gripper chain carries the web of bags hanging within the channel 92 until they are struck by an opening pin 76 passing through the slot 84 shown in FIG. 5. The web of separated bags then begins to open as the gripper chains diverge as shown by the chain guards 94. The angularly separating pair of gripper chains thus open the mouth of the bag defined by the top strips 36 by separating those top strips from each other. The partial-length slits 40 at the top of the perforation lines 38 allow for this separation and cause the mouth formed by the lips or top strips 36 to be substantially rectangular in configuration, allowing easy access into the bag for articles to be placed therein.

Also shown in FIG. 6 is a hydraulic lift mechanism 96 to elevate the entirety of the machine 10 at a desired level of the floor. A plurality of supporting feet 98 and associated lift mechanisms 96 are provided about the assembly 10.

Work shelves 100 are positioned on either side of an opening 102 through which the opened bags may be accessed for the depositing of materials. This depositing may be done either manually or automatically as with a filler mechanism or the like. It will be appreciated that the gripper chain passes along tracks provided beneath each of the work shelves and the separation of the track may be adjusted as will become apparent below to accommodate various size bags and associated bag openings.

An emergency stop button 104 is provided at the beginning of the work shelf conveyor area, as shown in FIG. 6 and, with reference to FIG. 1, it can be seen that an emergency stop button 104 is also positioned at the end of the work shelf area. Actuation of the emergency stop 104 signals the controller in the control box 24 to terminate operations.

With reference to FIG. 7, it can be seen that, at the end of the transport and filling section 18, there is a transfer region 22 where the gripper chain transport ends and the web of bags is sequentially transferred to pairs of transport belts, as will be described later. This transfer region 22 is then connected to the hot air sealer station 26, which will also be discussed below.

As shown in FIG. 7, a crank 106 is interconnected with a threaded shaft 108, which functions as a worm gear. The threaded shaft 108 engages a support mechanism for the opposed work shelves 100 and is operative to bring the work shelves closer together to narrow the open space 102, or to spread them apart to make that space larger. Typically, this movement will be a function of the nature and size of the bags being filled. It will be appreciated that the threaded shaft 108 has one end with a right-hand thread and the other end with a left-hand thread, such that the rotation of the single crank 106 and threaded shaft 108 can cause the shelves to move toward or away from each other, depending upon the rotational direction of the crank 106. A similar mounting arrangement is present at the opposite end of the work shelves 100, as shown in FIG. 6, although the corresponding crank 106 and threaded shaft 108 are not shown in that drawing. It is important that the tension on the gripper chains remains constant throughout the operation of the system, and that said tension be the same whether the gripper chains are close together or further apart as under control of the crank 106. To this end, a mounting plate 110 receives the cam drive sprockets for the gripper chains, as will be described with respect to FIGS. 8 and 9, and that mounting plate is received upon a pair of adjustment rails 112 by means of ways or slides 114. An air cylinder 116 is fixed to the plate 110 and, accordingly, to the driven cam sprockets of the gripper chains. The air cylinder 116 applies the same constant force to the plate 10 to ensure that the tension in the gripper chains remains constant regardless of the separation of the chains.

As shown in FIG. 8, the gripper chain drive mechanism is designated generally by the numeral 118 and includes a motor 120 with a toothed drive wheel driving a double-toothed belt 122 through an arrangement of wheels, and most particularly the sprocket drive wheels 124. Again, the double-sided or double-toothed belt 122 ensures that the pair of sprocket drive wheels 124 rotate in opposite directions and at the same speed.

As shown in FIG. 9, a motor gearbox 128 is interposed between the motor 120 and motor drive wheel. Moreover, the attachment block 130, secured to the mounting plate 110, is provided to attach to the piston rod of the air cylinder 116, to allow the air cylinder 116 to move the plate 110 upon the ways or slides 114 receiving the adjustment rails 112. Accordingly, it will be appreciated that air cylinder 116 is adapted to move the entire plate 110 containing the drive mechanism of the cam sprockets 54 at the drive end of the conveyor chain so as to maintain a constant tension in the gripper chain.

With reference now to FIG. 10, the chain-belt transfer mechanism 132, as a portion of the transfer region 22, is shown, absent the structure of the chain drive mechanism 118 just described. As shown, a pair of gripper belt pulleys 134 are each provided with a gripper belt 136. This is at the end of the gripper chain path of FIG. 9. The web of bags, interconnected by the top strips 36, is passed from the gripper chain interconnection as the cam sprockets release the top strips 36 and transport is continued by means of the gripper belts 136. This is primarily a frictional engagement of the top strips 36 and, for that reason, the support conveyor 20, shown in FIG. 1, serves a very useful purpose in this region. While the weight of full bags may be too much to be supported simply by the frictional engagement with the gripper belts 36, the weight of those bags can be received by the support conveyor 20. The web of bags 30 continues to be moved by the gripper belts 136 by appropriate drive means until transferred to sealer belts 138 as shown in FIG. 11. As apparent from FIG. 11, the sealer belts 138 are positioned below the gripper belts 136, with the sealer belts also being gripper belts associated with the heat sealer 26. The sealer belts 128 secure the web of bags 30 for a coextensive period of time that the gripper belts 136 are also securing the top strips 36. In that region, where both sets of gripper belts 136, 138 are engaging the top strips 36, a horizontal trimmer blade 140, positioned between the upper gripper belts 136 and lower gripper belts 138, slits and trims off the top portions of the top strips 36. At this point, both the path and the function of the gripper belts 136 end, the bags now being transported solely by the sealer gripper belts 138, with top edges of the top strips 36 being exposed thereabove. The sealer gripper belts 138 then transport the web of bags through the heat sealer 26.

As shown in FIG. 11, a hot air fan 142 blows hot air through tubes 144 to manifolds 146. The manifolds are spaced apart to accommodate the passage of the top edges of the remaining portions of the top strips 36 where the manifolds blow a hot air stream across the cut tops and melt or fuse them together, thereby sealing the tops of the bags 32 of the web 30. Exiting the manifolds 146, anvil rollers or nip rollers 148 engage the heated top sections of the melted top strips 36, further completing the fusing of them together. For this purpose, it will be appreciated that the bags 32 are preferably formed of a polyethylene material or other appropriate plastic or polymeric material that can be melted and fused together as just described.

Exiting the anvil nip rollers 148, the path of the white belts terminates at or about the pulley wheels 150 where the bags are released and dropped into an appropriate receiver. As further shown in FIG. 11, a servomotor 152 controls drive pulleys 154 to drive the gripper sealer belts 138.

The trim winder 28 is shown in FIG. 12. The winder 28 takes up the portions of the two top strips 36 that are slit off of the tops of the bags by the trimmer blade 140. The trim winder 28 comprises a screw rod 156 driven by an appropriate reversible servomotor 158. Mounted upon the screw rod 156 is a carriage 160, which is threadedly engaged to the screw rod 156 and translatable there across as driven by the motor 158. The carriage 160 is free moving upon a stabilizing guide rod 162. A ring 164 is suspended from the carriage 160 for receiving the trimmed material across a roller bar 166. The trimmed material passes over and is wound about a rotating take-up spool 168, driven by a motor 170. Photocells 172 are positioned at each end of the guide rod 162 to determine the presence of the carriage 160.

In operation, the take-up spool 168 is caused to rotate, taking up the trimmed material from the trim blade 140 and passing through the ring 164. The carriage 160 translates across the threaded screw rod 156 until its presence is detected by an associated photocell 172, at which time the motor 158 reverses direction, causing the carriage 160 to move back across the spool 168 until sensed by the other photocell 172, at which time the motor direction 158 again reverses such that the carriage 160 translates back and forth across the face of the spool 168. This prevents the trimmed material from bulking up on the spool 168, but ensures that it is uniformly spaced thereon, maximizing the amount that can be taken up on any given spool.

Thus, it can be seen that the various aspects of the invention may be achieved by the embodiments of the invention presented and described in detail herein. While in accordance with the patent statutes, only the best known and preferred embodiment of the invention has been presented and described in detail, the invention is not limited thereto or thereby. Accordingly, for an appreciation of the true scope of the invention, reference should be made to the following claims.

Claims

1. A bag loading and sealing system, comprising:

a continuous web of bags sharing a common tubular top strip;

a first station having a slitting blade for slitting said tubular top strip into a pair of opposed linear strips, and a gripper associated with each of said pair of opposed linear strips for gripping, opening and transporting said bags by each associated linear strip;

a transport and filling section in which an open mouth of each said bag is exposed for receiving material; and

a sealing section, sealing said linear strips together and thereby sealing each of said bags with material therein.

2. The bag loading and sealing system according to claim 1, wherein said bags of said continuous web of bags are separable from each other by lateral lines of perforation.

3. The bag loading and sealing system according to claim 2, wherein said first station further comprises a perforation separator for sequentially engaging said lateral lines of perforation and separating said bags from each other.

4. The bag loading and sealing system according to claim 3, wherein said perforation separator comprises an elongated member traversing said web at each said lateral line of perforation.

5. The bag loading and sealing system according to claim 3 further comprising an optical sensor monitoring movement of said bags and signaling when a lateral line of perforation is aligned with said perforation separator.

6. The bag loading and sealing system according to claim 3, wherein said grippers move in unison along paths that diverge, said diverging movement opening said bags and defining said mouth.

7. The bag loading and sealing system according to claim 6, wherein said grippers comprise gripper chains of interconnected gripping links caused to open and close by associated cam sprockets.

8. The bag loading and sealing system according to claim 7, wherein an extent of divergence of said paths of said gripper chains is adjustable.

9. The bag loading and sealing system according to claim 8, wherein said transport and filling section comprises a pair of work shelves having an opening therebetween, each of said gripper chains following a track beneath an associated one of said work shelves, a separation between said work shelves being adjustable by a threaded rod interconnecting said work shelves.

10. The bag loading and sealing system according to claim 9, wherein a pair of cam sprockets receiving said gripper chains are mounted to a slidable plate biased to maintain a constant tension on said gripper chains independent of said adjustable separation of said work shelves.

11. The bag loading and sealing system according to claim 10, wherein said slidable plate is biased by an air cylinder.

12. The bag loading and sealing system according to claim 6, wherein said lateral lines of perforation terminate at slits at an edge of said common tubular top strip, wherein said slits allow said mouth to form rectangularly.

13. The bag loading and sealing system according to claim 8, further comprising a first pair of belt grippers receiving said web of bags from said gripper chains and transporting said web of bags by an upper portion of said pair of opposed linear strips.

14. The bag loading and sealing system according to claim 13, further comprising a second pair of gripper belts engaging a lower portion of said pair of opposed linear strips.

15. The bag loading and sealing system according to claim 14, further comprising a trimming blade interposed between said first and second pairs of gripper belts, said trimming blade severing off an upper portion of said opposed linear strips.

16. The bag loading and sealing system according to claim 15, wherein said second pair of gripper belts transports said web of bags through a hot air sealer comprising said sealing section.

17. The bag loading and sealing system according to claim 16, wherein said hot air sealer comprises spaced manifolds receiving said second pair of gripper belts therebetween, said manifolds blowing hot air onto a top remaining portion of said opposed linear strips, melting and fusing them together.

18. The bag loading and sealing system according to claim 17, further comprising crimp rollers downstream of said manifolds for crimping said melted and fused portions of said linear strips.

19. The bag loading and sealing system according to claim 15, further comprising a trim winder receiving said upper portion of said opposed linear strips onto a spool.

20. The bag loading and sealing system according to claim 19, wherein said trim winder comprises a carriage reciprocatingly driving back and forth across a rod, said carriage receiving said trimmed upper portion of said opposed linear strips and transferring them onto said spool.

21. A method for opening, filling, and sealing the bags of a tubular web of interconnected bags, comprising:

slitting open a top edge of said web of bags to expose an interior of each bag;

gripping opposed flaps of said slit top edge by a moving gripper chain;

separating said bags of said web from each other;

opening a mouth of said bags by diverging travel of said moving gripper chain;

filling said bags with material;

transferring said filled bags to gripper belts;

slitting off top portions of said opposed flaps; and

heat-sealing together remaining portions of said flaps.