MXPA99010740A - Process for making packaging materials - Google Patents

Abstract

A process of manufacturing webs of side connected bags is disclosed. A tube of heat sealable material is flattened and spaced, transverse seals are formed from one edge of the tube toward the other to delineate bag sides. Thereafter, the seals are bisected by lines of weakness to facilitate separation of sides of adjacent bags. Longitudinal lines of weakness are formed immediately adjacent the seals to delineate the tops of bag faces and backs and a separate top or lip section.

Description

PROCEDURE FOR MANUFACTURING PACKAGING MATERIALS This invention is directed to a method for making continuous belts of interconnected bags used in packaging, and very particularly to a method for making continuous belts of bags that are opened to a rectangular configuration when they pass through a charging station.

Background of the invention The patent of E.U.A. 5,743,070, issued April 28, 1998 to Hershey Lerner and Dana J. üebhart (here "the SP patent") describes a packaging system that enjoys significant commercial success. With the machine of the SP patent, continuous ribbons of bags connected on the sides are used. Each continuous tape is an elongated and flattened plastic tube that includes an upper section which in turn is essentially a tube. During use, the upper section is fed on a mandrel and passed through a cutter that separates the upper section into two erect ridges. The flanges are held by single bands that are fed along diverging travel paths in parallel paths through a charging station. The single bands are described more fully in the U.S. patent. 5,722,218, issued on March 3, 1998 to Hershey Lerner under the title Plástic Transport System (here "the Belf patent.) The descriptions of the SP patent and the Belt patent are incorporated by reference. on the sides that hang from the flanges When a tape is fed along its travel path through a machine of the SP patent (the SP machine), lower resistance lines interconnecting the sides of adjacent bags are broken to leave individual tapes hanging from the flanges, as the bands diverge, the fastened flanges are separated from the hanging pouches along lines of least resistance to the extent necessary to cause the pouches to span the space between the parallel paths in an opening Generally, a problem that has been manifested is that the bags have not been opened consistently in rectangular configurations. They do not take other trapezoidal shapes. Moreover, the trapezoidal shapes adopted vary from continuous tape to continuous tape and in fact sometimes from bag to bag within the same continuous tape. Although it can be tolerated with some products the failure to open them creating a truly rectangular configuration, there are other products that make the machine system SP unacceptable. For example, if you try to pack sponges tightly together with the shape of a rectangular solid, it may be impossible to insert the products into bags other than the open ones in a rectangular configuration of the precise dimension required for each to receive a sponge and produce then a narrow-fitting bag around it.

BRIEF DESCRIPTION OF THE INVENTION It has been found that consistent rectangular bag openings are achieved if the side seals of the bag extend completely to the side edges of the bags adjacent to the upper portions of the bags immediately adjacent to longitudinal lines of lower strength than They connect the flanges to the bags. Although it can not be determined why the bags produced with said side seals assure rectangular openings, it is believed that this is because the seals ensure a concurrent start of an equal and opposite spacing of the ridges from the front and back surfaces of the bags, in relation to the side seals. It seems that if the side seals do not completely reach the sides of the bags adjacent to longitudinal perforations, there is a tendency for the front surface or the rear surface of a bag to begin to separate from the connected flange before the other one does, producing an unequal separation length between the flanges and the front and back surface of a certain bag. Accordingly, the object of the invention is to provide a novel and improved method for making a continuous belt of so-called side bag sacks in a chain, with procedures that secure bags that open in truly rectangular configurations when they are fed through the SP patent machine.

In the drawings Figure 1 is a perspective view and in a certain schematic form based on Figure 4 of the patent SP, which shows the continuous belt of this invention being fed through a charging station; Figure 2 is an elevation view of the loading section of the machine SP, showing the continuous belt of the present invention; Figure 3 is a fragmented and enlarged elevation view of a supply and bag preparation portion of the machine SP and the continuous belt, and Figure 4 is a flow diagram of the process.

Detailed description of the preferred embodiment With reference to the drawings, a continuous belt 15 of bags connected at the sides is provided. The continuous belt 15 is fed from a supply roll (not shown) to a bagging section 17 mounted on a support carriage 20. The continuous belt 15 is an elongated and flattened plastic tube, typically formed of polyethylene. The tube includes an upper section or flange 23 to be fed along a mandrel 24. The upper section 23 is connected to the upper portions of a chain of bags connected at the sides 25 by lines of least front and rear resistance that are they extend longitudinally in the form of perforations 27, 28. Frangible connections 30 connect side edges of adjacent bags. Each bag 25 includes a front surface 31 and a rear surface 32 interconnected in a bottom 33 by one selected from a fold or seal. The side seals 34 adjacent to the interconnections 30 delineate the sides of the bags 25. The front and rear surfaces 31, 32 of the bags are respectively connected to the upper section 23 by the lines of least resistance 27, 28 so that the upper section 23 is essentially a tube. The continuous belt 15 is fed into a bag feeding and preparation portion 35 of the bagging section 17. The feed is on the mandrel 24 and beyond a cutter 36, Figure 1. The cutter 36 separates the flange section 23 in opposite front and rear flanges. Feeding through the bag feeding and preparation portion 35 is caused by a pair of opposite leading end rotating conveyor belts 40, 41 supported by sets of rotating pulleys in opposite manner. A pallet 45 is provided which is shown in Figures 1, 2 and 3. The pallet is positioned a short distance upstream from a rolling cam 46. When the ridges are pulled by the main conveyor belts 41, 42, the ridges are bent respectively on the main conveyor belts under the action of the pallet 45. Once the ridges are bent over the tops of the main conveyor belts 41, 42, the cam 46 presses conveyor belts and endless fasteners 48, 49 in complementary grooves in the main conveyor belts 41, 42 respectively. In this way, the grooves function as bag holding surfaces that are complementary to the fastener bands 48, 49 as described in more detail in the Belt patent. A bag-side separating mechanism 53 is provided in a bag connection breaking station. The separation mechanism shown is not currently produced for machines of the SP patent. Since it is an operating mechanism and that the machine is described only as a reference and to explain the problem overcome by the present invention, that aspect of the present description has not been updated. The separating mechanism 53 includes an endless band 54 which is moved around a pair of separate pulleys 55 to provide extensions which, as shown in Fig. 1, are vertical. The pulleys 55 are driven by a motor 57, FIG. 2. As the belt is driven, rupture pins 58 projecting from the web 54 pass between adjacent sides of the bags to break the frangible interconnects 30. In this way, when moving away the bags, the feeding portion and bag preparation 35, are separated from each other but remain connected to the flanges 38, 39.

A charging station 60 includes a pair of parallel band separators 61, 62. The band separators are identical to each other. The band separators respectively include channels that respectively guide the main conveyor belts 40, 41 on each side of the loading station 60. When the conveyor belts 40, 41 are in the channels, as can be clearly seen in FIG. bags 25 are stretched between the bands in a rectangular top opening configuration. A schematic diagram showing a hopper 66 is included in Figures 1 and 2. As those figures suggest, the products to be packaged are deposited through the rectangular openings of the bag each time a bag coincides with the hopper in the bag. loading section. It is provided that a mechanism of adjustment of space. This mechanism includes a separate pair of adjusting screws 68, 69, FIG. 2. The adjusting screws 68, 69 have opposingly threaded sections that threadably couple the band separators 61, 62. Turning a crank 72 causes the rotation of the adjusting screw 69. The screw 69 is connected to the screw 70 by means of bands or chains 73, which function to transmit the rotational forces so that when the handle 72 is operated the screws 68, 69 also move to drive the spacers simultaneously in a spatially adjusted relationship, but still parallel.

When leaving the loaded bags from the loading station, it is desirable to return the upper portions of the front and back sides of the bag to juxtaposition. To facilitate that return, the upper parts of the bags are stretched. This stretching of the bags now loaded as they leave the charging station is achieved by air jets coming from nozzles 75, 76 directing respectively air streams against the leading and trailing edges of the bag being stretched. This stretching of the bags helps to move them from their rectangular orientations to juxtaposed relations from front surface to rear while the conveyor belts are returned to juxtaposition.

Continuous Tape Manufacturing The improved continuous tape manufacturing process is described in the flow chart of Figure 4. The equipment used in the manufacture of bag chains is well known to those skilled in the art. Consequently, the equipment itself is not shown. During manufacturing, it starts with a plastic tube that is heat sealed and sealable. Side seals 34 are formed. As best seen in FIG. 3, the side seals 34 extend from the bottoms 33 of the bags to the longitudinal perforations 27, 28 and completely to the sides of the bag. In fact, to ensure that the side seals extend completely to the sides of the bag, each seal 34 is wide enough to provide adjacent seals of adjacent bags.

After the side seals are formed, they are drilled to provide frangible connections between adjacent bags. The longitudinal lines of least resistance 27, 28 are formed to delineate the upper portions of the front and rear surfaces 31, 32 of the bags and the flange section 23. The longitudinal lines of least resistance are immediately adjacent (or adjacent through small portions) to the upper parts of the side seals. Although the sequence to form the longitudinal lines of least resistance and the lines of least resistance provided by the frangible bag connections is not important, it is important to form the lateral seals before the tube is perforated. If the perforations are formed first, the sealing operation can re-fuse the sides together, unless done with extreme care. The longitudinal lines of least resistance can be fused together or alternatively the seal can end up being separated from those lines. Again, it is important that the seals extend to both longitudinal lines of least resistance to secure rectangular bag openings. Although the invention has been described in its preferred form with some degree of particularity, it is understood that the present description of the preferred form has been made only by way of example and that numerous changes can be made in the details of structure, operation and combination and arrangement of the parties without departing from the spirit and scope of the invention claimed below.

Claims (9)

1. - A procedure for forming a chain of interconnected bags, connected in collateral relation, consisting of: a) forming a tube with one selected from a fold and a seal delineating the bottoms of the bags; b) forming a pair of lines of lesser elongated strength, spaced apart from and in parallel with the bottoms of the bags to delineate upper portions of front and rear surfaces; c) forming separate bag-side delineators, each transverse to the bag bottoms and each including a portion extending to the longitudinal lines of least resistance; and d) forming lateral lines of lesser strength in each of the side seals to delineate easily disconnectable sides of adjacent pockets.

2. The method according to claim 1, further characterized in that the elongated lower resistance lines are perforations in the front and back surfaces of the bags.

3. The method according to claim 1, further characterized in that the lateral lines of least resistance extend from the bottoms of the bags to the lines of lesser elongated resistance.

4. - The method according to claim 1, further characterized in that the side seals extend from the bottoms of the bags to the lines of least resistance elongated.

5. In a method for forming a continuous belt of bags connected on the sides having lines of lesser strength elongated between a continuous belt flange section that will form bag support flanges during a packing operation and front and rear surfaces of the bags being formed, the improved steps consist of: a) fusing sections of the front and back surfaces together at spaced intervals so that the fused sections extend transversely from the lines of least resistance elongated on one side of the lines of lesser strength elongated opposite said section of continuous tape flange towards the bottoms of the bags; and b) forming sidewalls of lower strength pouch in the fused sections extending from the lines of least resistance elongated to the bottoms of the bags to ensure in this way that the front and back surfaces of each bag are fused together in regions delineated each on either side by the lines of least resistance elongated and on the other side by the lateral lines of less resistance.

6. - The method according to claim 5, further characterized in that the lines of least resistance are perforations.

7. The method according to claim 6, further characterized in that the fused sections are formed by heat sealing.

8. The method according to claim 5, further characterized in that the fused sections are formed by heat sealing.

9. A method to form a continuous band of bags connected at the sides to assume rectangular upper openings when the bags are opened to receive products during a packing operation, the procedure consists of: a) flattening a heat sealable plastic tube to provide front and back sections; b) forming bag-side delineators between the front and back sections; the side seals being arranged transversely of the tube; c) perforating the front and back sections longitudinally to delineate upper portions of the bags and a flange section on one side of the longitudinal perforations and a bag section on the other side of the longitudinal perforations, the longitudinal perforations intercepting the seals; d) perforate the seals to delineate the sides of the bags that are being formed, the perforations of the seals extending from the bottoms of the bags to the longitudinal perforations to make possible in this way the lateral separation of the adjacent bags during the operations of packaging; and e) the perforations of the seals being located to generally bisect the seals transversely of the continuous belt, whereby each bag has separate sealed portions extending to the side edges of the bag and the upper part of the bag delineated by the longitudinal perforations. .