Patent Application
20050040278
This invention relates generally to the manufacture, distribution, and utilization of trash bags, and more particularly to the dispensing of overlapping wave-cut trash bags.
Trash bags are utilized throughout the world for refuse collection and disposal, storage, and other purposes. Most trash bags are manufactured by the blown-film extrusion process which includes forming a blown-film tube from polyethylene or other polymeric materials, flattening the blown-film tube, and then segregating the flattened tube into individual trash bags by forming seals which extend transversely across the entire width of the tube. Typically a line of perforations is formed immediately adjacent and parallel to each seal to facilitate separation of the trash bags one from another. After the trash bags are sealed and perforated, they are typically twice-folded axially into a fractional width configuration.
Traditionally, trash bags have been manufactured and sold in rolls comprised of individual trash bags connected end to end. The rolls of end-to-end connected trash bags are packaged in boxes or suitable containers for distribution. Whenever a trash bag is needed, the consumer unwinds the outermost trash bag from the roll and then separates the trash bag from the roll by tearing the line of perforations which connect it to the following bag of the roll.
More recently overlapping trash bag dispensing has evolved. In accordance with the overlapping dispensing technique, trash bags that otherwise would be connected end-to-end are separated from one another at the point of manufacture. Following separation the leading end of each following trash bag is positioned in an overlapping relationship with the trailing end of the preceding trash bag prior to the winding of the trash bags into a roll. The completed rolls of trash bags are positioned in containers having slots formed therein which extend parallel to the axis of the roll. Whenever it is desired to remove a trash bag from the roll, the leading end of the outermost trash bag on the roll is pulled through the slot in the container thereby disengaging the trash bag from the roll and simultaneously pulling the leading end of the next trash bag of the roll through the slot. This results in making the next succeeding trash bag readily available whenever it may be needed.
In the case of trash bags which are rectangular in shape at both ends, the separation of a following trash bag from the next preceding trash bag and the positioning of the leading end of the following trash bag in an overlapping relationship with respect to the trailing end of the preceding trash bag is relatively straightforward. As indicated above, trash bags are typically folded at least twice axially into a multi-layer, fractional width configuration prior to being wound into rolls. Even with the trash bags folded into as many as four layers, it is feasible to direct a signal, typically an electric spark, through the perforations situated next to the seal which separates the leading and following trash bags. The signal passes through the perforations and engages a suitable target which triggers the steps involved in separating the following trash bag from the leading trash bag and positioning the leading end of the following trash bag in an overlapping relationship with the trailing end of the leading trash bag.
It is also known to provide wave-cut trash bags. A wave-cut trash bag has a wave or lobe-shaped configuration at its open end. This provides two or more lobes which can be used to tie the trash bag in a closed configuration after it is filled.
Wave-cut trash bags are typically manufactured by providing sets of closely spaced, parallel transversely extending seals at predetermined intervals along the length of a flattened blown-film polymeric tube. A transversely extending line of perforations is provided between the closely spaced, parallel seals. A wave or lobe-shaped line of perforation is formed across the flattened blown-film tube at a location equidistant between successive sets of spaced, parallel seals.
Prior to the present invention at least three factors have prevented the successful application of overlapping dispensing to wave-cut trash bags. First, because wave-cut trash bags are folded axially into a fractional width configuration, the lobe or wave-shaped line of perforations which define the open ends of the trash bags are non-aligned. This fact negates the traditional method of identifying trash bag ends by directing a signal through perforations comprising all of the trash bag layers. Second, the perforations which are utilized to separate adjacent trash bags comprising a flattened blown-film polymeric tube are traditionally evenly spaced. However, it has been found that the use of evenly spaced perforations at the lobe or wave-shaped ends of wave-cut trash bags results in force concentrations which in turn causes skewing of the trash bags when wave-cut trash bags are separated longitudinally to facilitate the overlapping dispensing process. Third, when wave-cut trash bags are folded axially to provide a fractional width configuration and are subsequently separated longitudinally to facilitate overlapping dispensing, one of the lobes of the wave-cut open end of the trash bag forms a single layer extension which must be manipulated in order to position the leading end of the following trash bag in an overlapping relationship with the trailing end of the preceding trash bag. Heretofore it has not been considered possible to utilize the traditional air current technique to manipulate the single polymeric layer.
The present invention overcomes the foregoing and other problems which have long since characterized the prior art. In accordance with the broader aspects of the invention, identification of the lines of perforations which separate adjacent trash bags is accomplished by positioning a signal receiving target between the folds defining the layers of the trash bag thereby eliminating the requirement of directing a perforation identifying signal through all of the layers comprising the trash bag. The line of perforations connecting the open ends of wave-cut trash bags are arranged in accordance with a predetermined pattern thereby avoiding stress concentrations and preventing skewing of the trash bags when the trash bags are separated longitudinally to facilitate the overlapping dispensing procedure. Manipulation of the separated trash bag ends to facilitate the overlapping dispensing process will be facilitated by selectively applying static electricity to the trash bag ends thereby temporarily bonding the layers comprising the trash bag one to another.
A more complete understanding of the invention may be had by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings, wherein:
Referring now to the Drawings, and particularly to
The flattened blown-film polymeric tube 12 is first directed into a bag machine 16 which separates the flattened blown-film polymeric tube 12 into sequential sections 18. The sections 18 are separated one from another by equally spaced seal/perforation zones 20.
Referring momentarily to
The seals 22 may be formed my positioning a heated bar on one side and a cooperating anvil on the opposite side of the flattened tube 12. The heated bar engages the flattened tube 12 under predetermined pressure thereby softening the material of the tube 12 sufficiently to form a permanent bond between the opposite sides thereof. The line of perforation 24 is formed by positioning a toothed bar and a cooperating anvil on opposite sides of the flattened tube 12. The tooth bar is advanced into engagement with the underlying anvil thereby forming the perforations comprising the line of perforations 24. As will be appreciated by those skilled in the art, various other procedures may be utilized to form the seals and/or the perforations comprising the seal/perforation zone 20.
Referring again to
The lobe or wave shaped line of perforation 30 may be formed by positioning a star wheel having a toothed periphery and an anvil wheel having a flat periphery on opposite sides of the flattened tube 12. The star wheel is advanced into engagement with the anvil wheel thereby initially perforating the flattened tube 12. While the star wheel and the anvil wheel remain in engagement, they are moved laterally across the width of the tube 12 following a curvilinear path thereby forming the lobe or wave shaped line of perforations 30. Other techniques for forming the lobe or wave shaped line of perforations will readily suggest themselves to those skilled in the art.
Referring simultaneously to
The winding machine 34 performs three functions with respect to the flattened blown-film polymeric tube 12. First, the winding machine 34 separates the tube 12 at each perforation line 24 and at each perforation line 30 thereby transforming the tube 12 into a series of individual trash bags each having a seal 22 at one end and a wave-cut opening defined by the line of perforation 30 at the opposite end. Second, the winding machine 34 positions the leading end of each following trash bag in an overlapping relationship with the trailing end of the preceding trash bag thereby facilitating overlapping dispensing of the trash bags formed from the flattened blown-film polymeric tube 12. Third, the winding machine 34 winds the trash bags into a roll for subsequent packaging and delivery to the ultimate consumer.
Referring to
Referring specifically to
Having reference to
Referring to
Referring to
Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.
