Packaging process for a web of interconnected bags

Abstract: In a packaging process utilising a chain (15) of side connected bags (25), the chain is fed from a supply to a load station (60). Portions of a face (31) and a back (32) of each bag are separated to provide a top opening affording access to a fill space. A product is placed in the space of each bag to fill the bag. Upper portions of the face and back of each bag are brought into juxtaposed registration by oppositely directing two streams of air under pressure from nozzles (110, 112) respectively against spaced interior side portions of each loaded bag.

Description: This invention relates to packaging machinery and more particularly to a packaging machine and method of packaging which are especially well suited for loading relatively bulky and liquid products sequentially into bags of a novel, side interconnected, chain of bags. Background of the Invention U.S. Patent 4,969,310 issued November 13, 1990 to Hershey Lerner et al. under the title Packaging Machine and Method (the SP Patent) discloses a packaging machine which has enjoyed commercial success. One of the major advantages of the machine of the SP Patent resides in a novel conveyor belt mechanism for gripping upstanding lips of bags of a chain as they are transported along a path of travel and registered at a load station. The firmness with which the lips are gripped makes the machine highly suitable for packaging bulky products which are stuffed into the bags. While the machine of the SP Patent was an advance over the prior art, especially in terms of its lip gripping capability, even greater lip gripping capabilities, if achieved, would be useful in enabling packaging of additional products. While the machine was a definite advance over the art, as to any given bag size, it has a finite maximum stuffing pressure it can withstand without slippage. The length of a bag along the path of travel is limited, loading of a bag while it moves along the path of travel is not possible and the concurrent loading of two or more bags is not available. With the machine of the SP Patent there is an intermittent section which includes the loading station and a continuous section which includes a sealing station. The through-put of the machine is inherently less than could be achieved with a continuously operating loading section. One prior machine provides rectangular openings, the dimensions of the rectangular openings, both longitudinally and transversely, are limited both by the construction of the chain of bags being filled and by guide rods used to transport the bags. To the extent, that the packaging machine could be adjusted to vary the configuration of the rectangular opening, such available adjustment was extremely limited because it required substitution of a different set up guide rods. Summary of the invention The present invention provides a packaging process utilising a chain of side connected bags, the process comprising: a) feeding the chain from a supply to a load station; b) separating portions of a face and a back of each bag to provide a top opening affording access to a fill space; c) placing a product in the space of each bag to fill the bag; and, d) characterised by bringing upper portions of the face and back of each bag into juxtaposed registration by oppositely directing two streams of air under pressure from nozzles respectively against spaced interior side portions of each loaded bag in regions of leading and trailing edges of the bag respectively such that the upper portions of the bag are stretched longitudinally of the path of travel. A major feature of the present machine is that the loading section opens the bags into rectangular configurations. The transverse and longitudinal dimensions of such openings for any given bag size are relatively and readily adjustable over a wide range. There is essentially no limit to the length of the loading station and multiple numbers of open bags can be concurrently conveyed through the loading station. With a machine operating on a continuous basis and a synchronised product supply one is able to concurrently transfer a set of products into a like numbered set of bags as the bags and the conveyed products advance through the load station. Another advantage of an elongated load station is that one may position a series of vibrator feeders along the station thus, eliminating the need for a feed conveyor. Extremely high rates of packaging can be achieved. For example, it is possible to load and seal 130 25.4 cm (ten inch) bags per minute. Rates achieved are in excess of those achieved with virtually all, if not all, prior art machines including so called "form and fill" machines. As loaded bags exit the load station the lead side edge is advanced and the trailing side edge of each bag is retarded to bring inside surfaces of the top portions of each bag back into surface to surface touching orientation for sealing. Oppositely directed jets of air are employed which are effective to re-establish the surface to surface orientation. At an exit from the bagging section of the machine, the main transport belts overlie exit belts which in turn overlie the closure section transport belts. As the bags are transferred to the closure section belts, a rotary knife cuts the bags. near their tops such that the lip portions that have been carried by the main transport belts are cut off and become recyclable scrap. The elevation of the cutter relative to the heat sealer is adjustable. The invention also encompasses a process of packaging which includes gripping the upstanding front and back lip portions between main and lip transport belts. The belts are then spread as they pass through a load station pulling bag openings into rectangular configurations as portions of bag tops are separated from the top section. After bag loading, top portions of the bag inner surfaces are returned to abutting engagement, a portion of the lip section is trimmed from the bags, and the bags are sealed or otherwise closed to complete packages. In the Drawings Figure 1 is a fragmentary top plan view of the bagger section of the machine; Figure 2 is a foreshortened elevational view of the bagger section as seen from the plane indicated by the line 3-3 of Figure 1; and Figure 3 is a fragmentary perspective view showing an arrangement for flattening bags. Detailed Description of the Preferred Embodiment I. The Overall Machine Referring to Figures 1 and 2 a web of side connected bags 25 is provided. The web is fed from a supply shown schematically at 16 to a bagger section 17. The bagger section 17 is separably connected to a sealer section 19. II. The Web The web is an elongated flattened plastic tube, typically formed of polyethylene. The tube includes a top section 23 for feeding along a mandrel 24, Figure 2. The top section 23 is connected to the tops of a chain of side connected bags 25 by front and back lines of weakness in the form of perforations 27, 28. Frangible connections 30 connect, adjacent bag side edges, Figures 3 and 4. Each bag 25 includes a face 31 and a back 32 interconnected at a bottom 33 by a selected one of a fold or a seal. Side seals adjacent the interconnections 30 delineate the sides of the bags 25. The bag faces and backs 31, 32 are respectively connected to the top section 23 by the lines of weakness 27, 28, such that the top section 23 when the web is flattened itself is essentially a tube. III. The Bagger Section 17 A. A Bag Feed and Preparation Portion 35 The web is fed from the supply 16 into a bag feed and preparation portion 35 of the bagger section 17. The feed is over the mandrel 24 and past a slitter 36, Figure 1. The slitter 36 separates the top section 23 into opposed face and back lips 38,39. The feed through the bag feed and preparation portion 35 is caused by a pair of endless, oppositely rotating, main transport belts 40, 41 supported by oppositely rotating pulley sets 42, 43. The main belts 40, 41 are driven by a stepper motor 44, Figure 2 through toothed pulleys 42T, 43T of the sets 42, 43. Other of the pulleys 42S, 43S are spring biased to tension the belts. A plow 45 is provided and shown in Figure 2. The plow is positioned a short distance upstream from a roller cam 46. As the lips are drawn along by the main transport belts 41, 42, the lips are respectively folded over the top bag engaging surfaces of the main transport belts under the action of the plow 45. Once the lips are folded over the tops of the main transport belts 41, 42, the roller cam 46 presses endless, lip transport and clamp belts 48, 49 into complemental grooves in the main transport belts 40, 41 respectively. Thus, the grooves function as bag clamping surfaces that are complemental with the clamping belts 48, 49. A bag side separator mechanism 53 is provided at a bag connection breaking station. The separator mechanism 53 includes an endless belt 54 which is trained around a pair of spaced pulleys 55 to provide spans which, as shown in Figure 3, are vertical. The pulleys 55 are driven by a motor 57, Figure 2. As the belt is driven breaking pins 58 projecting from the belt 54 pass between adjacent sides of bags to break the frangible interconnections 30. Thus, as the bags depart the bag feed and preparation portion 35, they are separated from one another but remain connected to the lips 38, 39. B. The Load Station 60 The load station 60 includes a pair of parallel belt spreaders 61, 62. The belt spreaders are mirror images of one another. The belt spreaders respectively include channels. The channels respectively guide the main transport belts 40, 41, on either side of the load station 60. When the transport belts 40, 41, are in the channels the bags 25 are stretched between the belts in a rectangular top opening configuration. A schematic showing of a supply funnel 66 is included in Figure 2. As suggested by that figure, the products to be packaged are deposited through the rectangular bag openings each time a bag is registered with the supply funnel at the load station. A space adjusting mechanism is provided. This mechanism includes a spaced pair of adjustment screws 68, 69, Figure 2. The adjustment screws 68, 69 are respectively centrally journaled by bearings 70, 71. The screws have oppositely threaded sections on either side of their bearings 70, 71 which threadably engage the belt spreaders 61, 62. Rotation of a crank 72 causes rotation of the adjustment screw 69. The screw 69 is connected to the screw 70 via belts or chains 73, which function to transmit rotation forces so that when the crank 72 is operated the screws 68, 69 are moved equally to drive the spreaders equally into an adjusted spacial, but still parallel, relationship. As the spreaders are movably adjusted toward and away from one another, the spring biased pulleys 42S, 43S maintain tension on the main transport belts 40, 41 while permitting relative movement of spans of the belts passing through the spreader channels 63, 64. Similarly, spring biased lip transport belt pulleys 50S maintain tension on the clamp belts 48, 49. The spring biased pulleys of both sets are the pulleys to the right as seen in Figure 1, i.e. the entrance end pulleys in the bag feed and preparation portion 35. The main transport pulley sets 42, 43 include two idler pulleys 75, 76 downstream from the load station 60. The idler pulleys 75, 76 are relatively closely spaced to return the main transport belts 40, 41 into substantially juxtaposed relationship following exit from the load station 60. C. Bag Stretching As loaded bags exit the load station, it is desirable to return upper portions of the bag faces and backs into juxtaposition. This stretching of the now loaded bags as they exit the load station is accomplished with jets of air from nozzles 110, 112 which respectively blow against the lead and trailing edges of the bag, thus stretching the bags from their rectangular orientation into a face to back juxtaposed relationship as the transport belts are returned to juxtaposition. After loaded bags have exited the load station 60 and the face and back of each bag have been brought into juxtaposition, the loaded bags are transferred to the closure section. VIII. Operation Next a web 15 of bags 25 is fed through the bagger and sealer by jogging the two. The transverse spacing of the main conveyor belts 40, 41 is adjusted by rotating the crank 72 until the load station 60 has the desired transverse dimension. A control, not shown, is set to provide a desired feed rate and a selected one of continuous or intermittent operation. Assuming continuous operation, the feed rate may be as high as 130 25.4 cm (ten inch) bags per minute. Once the machine is in operation, the top section 21 of the web 15 is fed along the mandrel 24 and slit by the slitter 36. This forms the lips which are folded over the main transport belts 41, 42 by the action of the plow 45. The lip clamp belts 48, 49 descend from the elevated and spring biased pulleys 50S, as shown in Figure 2. The roller cam 46 cams the clamp belts 48, 49 respectively into the transport belt recesses to provide very positive and firm support for the bags as they are further processed. As successive side connections 30 of the bags are registered with the bag side separator 53, the motor 55 is operated to drive the belt 54 and cause the breaker pins 58 to rupture the side connections 30. As adjacent runs of the transport belts 41, 42 progress downstream from the bag feed and preparation portion 35, the belts are spread under the action of the belt spreaders 61, 62. As the belts are spread, the lips cause the front and back faces 31, 32 adjacent the lead edge of each bag to separate from the lips by tearing a sufficient length of the perforations between them to allow the lead edge to become the mid point in a bag span between the belts as the bag passes longitudinally through the load station 60. Similarly, the perforations adjacent the trailing edge are torn as the trailing part of the bag is spread until the bag achieves a full rectangular opening as shown in Figure 1 and 3 in particular. Next a product is inserted into the rectangular bag as indicated schematically in Figure 2. While the schematic showing is of discrete fasteners, it should be recognised that this machine and system are well suited to packaging liquids and bulky products which must be stuffed into a bag, such as pantyhose and rectangular items, such as household sponges. After the product has been inserted, the adjacent runs of the main transport belts are brought back together and the loaded bag tops are spread longitudinally of the path of travel by opposed air streams from nozzles 110, 112.

Claims: A packaging process utilising a chain (15) of side connected bags (25), the process comprising: a) feeding the chain from a supply to a load station (60); b) separating portions of a face (31) and a back (32) of each bag to provide a top opening affording access to a fill space; c) placing a product in the space of each bag to fill the bag; and, d) characterised by bringing upper portions of the face and back of each bag into juxtaposed registration by oppositely directing two streams of air under pressure from nozzles (110, 112) respectively against spaced interior side portions of each loaded bag in regions of leading and trailing edges of the bag, respectively such that the upper portions of the bag are stretched longitudinally of the path of travel. The process of claim 1 further including the step of securing the upper portions together while juxtaposed. The process of claim 1 or claim 2 wherein the feeding step includes grasping upper lips connected to the bag faces and backs. The process of claim 2 wherein the separating step is accomplished by spreading the lips as they are transported along a path of travel through the load station. The process of any of the preceding claims further including grasping the registered top portions between a pair of belts (40, 41) to maintain registration of the portions as the registered portions are fed downstream.

Inventors: LERNER HERSHEY, LERNER, HERSHEY
Applicants: AUTOMATED PACKAGING SYST INC, AUTOMATED PACKAGING SYSTEMS, INC.
Application year: 1997
Main classification: B65B43
IPC codes: B65B43