FIELD OF INVENTION

The invention pertains to film bags typically used for groceries, produce or other merchandise. More particularly, the invention relates to film bags for use with dispensing racks that are designed to open as bags are pulled from the dispenser.

BACKGROUND OF THE INVENTION

Film bags are commonly used in supermarkets, department stores and similar applications. These bags have advantages in that they are relatively inexpensive to produce, provide substantial carrying capacity and may include easily used handles. In order to make these bags easier to handle and easier to fill, they are usually used in combination with a dispensing rack or hook. Dispensing racks typically include a pair of horizontally oriented arms from which the bags are suspended by means of holes in upper portions of the bags. If the bags can be made to open as they are pulled from the dispensing rack or hook, they become substantially easier to use. Various techniques have been developed for causing film bags to open as they are removed from dispensing racks or hooks.

U.S. Patent Application No. 2005/0087542, issued to Bazbaz is directed to a tabless, self-opening T-shirt-styled film bag is provided having a handle, stress relief notch, and mounting tab structure for providing a wide-opening bag mouth and a bag having high weight carrying capacity. Handles have a narrow upper portion, a wide middle portion and a narrow lower portion. Handle mounting apertures are provided in the wide middle portion, which projects inwardly above the mouth of the bag. The handle mounting apertures are formed by a blade having an elongate section that is bent to form an obtuse angle.

The handle mounting aperture has a sufficient width for accommodating arms of a dispensing rack and a height about three times as great as the width. The bag has a central mounting tab extending above the mouth of the bag and between the handles. A stress relief notch having a reasonably tight radius of curvature is provided between each handle and the mounting tab. The mounting tab has a mounting aperture formed by two blades meeting at a sharp corner, the corner having essentially no radius of curvature. A severable region is provided between the corner and an outer edge of the mounting tab, which can tear as the bag is removed from a mounting hook on a dispensing rack. Multiple bags are aligned and bonded together to provide a unitary pack, where pulling one bag off a dispensing rack pulls an adjacent bag open.

U.S. Pat. No. 4,676,378 issued to Baxley et al., discloses a bag pack comprising a stack of film shopping bags that are bound together and mounted on a rack in such a manner that as one is removed from the rack, the next is opened and remains on the rack to receive material therein.

The rack that is used in this invention for the bag pack comprises a flat base with a pair of laterally spaced support arms to accommodate fully expanded bags with handles engaged with the support arms. A transverse member extends between the support arms to support a tab receiving hook element for engagement through the tab apertures. When the bag pack is produced, and either prior to or simultaneously with the forming of a cut line through the stacked bag handles, the flaps are bonded together throughout the full stack. This is done by use of a heated pin or rod extended centrally through the flaps to directly heat seal the flaps together.

U.S. Pat. No. 6,105,780, issued to Nguyen describes a bag and dispensing system wherein the thermoplastic bag to be dispensed may be retained in an open position, to allow for the loading thereof with contents for carrying, such as purchased goods or the like. The system is further configured such that the loaded bag, when dispensed, draws the next bag in the stack forward into an open loading position such that it is ready to be loaded with goods without further manipulation by the attendant. The preferred embodiment of the present invention teaches the utilization multi-edged punch applied to the handle area of the bags to hold said handles together for handling of the bag pack, and for facilitating opening of the next bag in the stack on the rack, when a loaded bag is removed.

The preferred embodiment of the present invention utilizes co-extruded film, wherein there is provided a high density film having bonded thereto a lower density film of lesser density than said high density film, such that said lower density film forms the exterior side of said co-extruded film. The co-extruded film is then corona treated at a higher energy level than that recommended for facilitating a printing surface on said film. The film is then die-cut to form bag packs, and simultaneously punched with the multi-faceted punch in the area of the handles. This punch impacts the film forming the bag walls, melding the adjacent walls together in a releasable fashion, allowing self opening of said bags.

U.S. Pat. No. 5,207,328, issued to Huang et al. is directed to a pack of self-opening bags with a front, rear, and co-joined side walls, with front and rear tabs extending from top edges of the front and rear walls. The tabs have a curved aperture slits therein, and the tabs are frangibly adhered together with contact adhesive. The slit has a main cut section, a first curved end section at one end, and a second curved end section at the opposite end. The first curved section has a curve that extends upwardly and inwardly from the main cut section. The second curved section has a substantially semi-circular curve that extends from the main cut section in a direction towards the bottom edge of the tab and has an end that is substantially perpendicular to and adjacent the main cut section. In one embodiment, the first curved section is dashed.

U.S. Patent Application No. 2002/0108882 issued to DeMatteis is directed to a tab for mounting a bag bundle on a retaining hook of the type having an upwardly bent hook is shown configured in a bundle of bags. The bundle of bags has at least a leading bag and a plurality of trailing bags. There is at least one tab attached to one bag wall of each bag. This tab is in alignment with like tabs from like bag walls. The tab includes a flanged aperture including at least one peak, with this peak protruding inwardly toward and to the aperture for contact with the upwardly bent hook whereby the tabs are bent out of alignment with the upwardly shaped hook.

U.S. Pat. No. 4,636,191 issued to Piggott discloses a bag making machine for producing bags from an elongate strip of plastic web material. The disclosure relates to various improvements in the bag making machine such as the apparatus for cutting the bag handle aperture. The apparatus includes at least one circular cutting blade having a plunger movable relative thereto within its cutting periphery. The plunger includes a web piercing member on its leading face which member positively holds the web material relative to the cutting blade and plunger.

U.S. Patent Application No. 2004/0074364, issued to Prudhomme describes a multiple variable punch assembly is configurable for punching holes and slits in a plastic film material. The assembly has frame is positioned below the plane of film with one or more transverse carriages positioned to slide on the sides of the frame. Each of the carriages has side plate members, and upper and lower rails extending across the frame in the transverse direction. The upper rail is positioned above the plane of the film and the lower rail is positioned directly below the upper rail and below the film web plane. The positions of the carriages can be adjusted along the frame in the machine direction. The punch head assemblies are adjustably mounted the carriages, with an upper plate fitted onto the upper carriage rail and a lower backing plate situated beneath it on the lower carriage rail. An alignment pin can be inserted into aligned holes for positioning the upper plate and the lower backing plate. An auxiliary carriage can be mounted on one of the main carriages, and provides a pair of auxiliary rails for mounting an additional punch head.

While other variations exist, the above-described designs for self-opening bag packs are typical of those encountered in the prior art. It is an objective of the present invention to provide for a film bag pack that is suitable for use with standardized dispensing racks and includes at least one self-opening feature. It is a further objective to provide this capability in a bag pack that includes bags that are durable, break-resistant and easily produced. It is a still further objective of the invention to provide the above-described bag packs without the need for localized compressed areas in the bag pack. Finally, it is an objective of the invention to provide bags that open with uniform force from the first bags of the pack to the last.

While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified.

SUMMARY OF THE INVENTION

The present invention addresses all of the deficiencies of prior art self-opening bag pack inventions and satisfies all of the objectives described above.

(1) A self-opening wide mouth carryout bag pack providing the desired features may be constructed using the following apparatus. A supply of flexible film material is provided. An extruder is provided. The extruder forms a continuous tube of film. A folder is provided. The folder folds in first and second side gussets. A flattener is provided. The flattener forms a continuous flattened tube. A first sealer is provided. The first sealer forms a bottom seal across a width of the flattened tube at a predetermined interval. A cutter is provided. The cutter cuts the flattened tube into bag blanks at a predetermined distance from the bottom seal. The bag blanks have front and rear walls, first and second side edges, a top edge, a bottom edge and a mouth portion.

A second sealer is provided. The second sealer forms a first angle seal. The first angle seal extends from the first side edge of the front and rear walls across the bottom seal at a point spaced outwardly from an innermost portion of the first side gusset at the bottom edges of the front and rear walls. A third sealer is provided. The third sealer forms a second angle seal. The second angle seal extends from the second side edge of the front and rear walls across the bottom seal at a point spaced outwardly from an innermost portion of the second side gusset at the bottom edges of the front and rear walls. A stacker is provided. The stacker forms the bags into a bag pack with the top edges aligned. A die cutter is provided. The die cutter cuts a bag mouth orthogonal to a length of the flattened tube and cuts a handle opening adjacent the bag mouth. The first and second angle seals create a wide mouth carryout bag having a substantially flat bottom when the bag is opened. The flat bottom has three layers of material in the region formed from the first and second angle seals. The substantially flat bottom includes two layers of bag material extending beyond the bottom seal. An aperture maker is provided. The aperture maker penetrates the bag pack and forms first and second apertures for suspending the bag pack from a dispensing rack.

An adhesion knife is provided. The knife has a single non-linear elongated cutting edge and provides a single non-linear elongated knife cut. The single non-linear knife cut extends completely through front and rear walls of each of the bag blanks in the bag pack. The knife cut has first and second ends and first and second elongated non-linear edges. The knife cut adheres adjacent bag blanks together in the bag pack along both of the first and second elongated non-linear edges and provides self-opening features.

The bag pack is suspended from the dispensing rack and a first bag is pulled outwardly from the bag pack, the first and second edges of the knife cut in the front wall of a subsequent bag will be adhered to the first and second edges of the knife cut in the rear wall of the first bag, thereby causing the first bag to open.

(2) In a variant of the invention, the first and second edges of the knife cut are spaced apart by a distance ranging from 0.02 inches to 0.3 inches.

(3) In yet another variant, the knife cut is S-shaped.

(4) In a further variant, the knife cut is Z-shaped.

(5) In still a further variant, the knife cut is in the form of a straight line, said straight line having at least one curved section at either of first and second ends of the straight line.

(6) In yet further variant, a corona treater is provided. The corona treater treats at least one of the front and rear walls. The corona treatment provides additional adhesion for printing ink on the bag walls.

(7) In another variant, a dual corona treater is provided. The dual corona treater treats the front wall and the rear wall, thereby providing additional adhesion between adjacent bags in the bag pack and enhancing self-opening capability for the bag pack.

(8) In still another variant, the die cutter forms the bag mouth in a wave form.

(9) In yet another variant, the die cutter forms the bag mouth with a central mounting tab. The central mounting tab has at least one mounting opening. The opening is sized and shaped to fit slidably over a central dispenser rack mounting hook, the central mounting tab is frangibly attached to the top edges of the front and rear walls above the handle opening.

(10) In another variant of the invention, the central mounting tab further includes an alignment feature. The alignment feature fastens the central mounting tab to a subsequent central mounting tab in the bag pack, thereby permitting easy mounting of the central mounting tabs to the dispensing rack.

(11) In still another variant, the alignment feature is selected from the group comprising: proprietary bag material formulations, hot pinning, cold staking, glue spotting, knife cutting, adhesive inks and corona treatment with pressure.

(12) In a further variant, the aperture maker forms apertures including a first dispenser arm mounting aperture and a second dispenser arm mounting aperture. The first aperture penetrates the front and rear walls and the first side gusset adjacent the first side edge and the top edges of the front and rear walls. The second aperture penetrates the front and rear walls and the second side gusset adjacent the second side edge and the top edges of the front and rear walls.

(13) In still a further variant, the die cutter forms the bag mouth with a central, frangible mounting opening. The central, frangible mounting opening is centrally located in the front and rear walls adjacent the top edges of the front and rear walls and is adapted to break apart with sufficient pressure from a force of removing the wide mouth carryout bag from the dispensing rack, the central frangible mounting opening remaining with the bag when dispensed.

(14) In yet a further variant, at least one additional self-opening feature is provided, the at least one additional self-opening feature is selected from the group comprising: proprietary bag material formulations, hot pinning, cold staking, glue spotting, adhesive inks and corona treatment with pressure.

(15) In another variant of the invention, the proprietary bag material formulations comprise 0.5 wt. % slip and antiblock compound.

(16) In still another variant, the proprietary bag material formulations comprise 1-3 wt. % calcium carbonate.

(17) In yet another variant, the proprietary bag material formulations comprise 10-20 wt. % recycled material, the recycled material comprising about 40-49 wt. % high density, high molecular weight polyethylene, 12-20 wt. % high density, medium molecular weight polyethylene, 20-30 wt. % linear low density polyethylene, 0-8 wt. % color concentrate.

(18) In a further variant, the proprietary bag material formulations wherein 10-15 wt. % of the linear low density polyethylene has a density ranging from 0.923-0.924 gm/cc.

(19) In still a further variant, the proprietary bag material formulations wherein 10-15 wt. % of the linear low density polyethylene has a melt index ranging from 0.25-0.30 gm/10 minutes.

(20) In yet a further variant, the proprietary bag material formulations wherein the high density, medium molecular weight polyethylene has a density ranging from 0.937-0.947 gm/cc.

(21) In another variant of the invention, the proprietary bag material formulations wherein the high density, medium molecular weight polyethylene has a melt index ranging from 0.10-0.30 gm/10 minutes.

(22) In still another variant, the at least one additional self-opening feature is located adjacent the top edges of the front and rear bag walls.

(23) In yet another variant, the at least one additional self-opening feature is located below the first and second apertures for suspending the bag pack from the dispensing rack.

(24) In a further variant, the handle opening is of the form selected from the group comprising round, oval, racetrack, kidney shaped and elongated round.

(25) In still a further variant, the dispensing rack included a base. The base is sized to accommodate a fully open wide mouth carryout bag. A central dispenser rack mounting hook is provided. The central mounting hook is attached to a central support that extends upwardly from the base and is adapted to position a pack of wide mouth carryout bags above the base using the central mounting tab. First and second side mounting arms are provided. The first and second side mounting arms are attached to the central support. The first and second side mounting arms are adapted to engage the first and second dispenser arm mounting apertures, position a pack of wide mouth carryout bags above the base and to maintain the bags in an open position for loading.

(26) In a final variant of the invention, the dispensing rack comprises a base. The base is sized to accommodate a fully open wide mouth carryout bag. A central dispenser rack mounting hook is provided. The central mounting hook is attached to a central support extending upwardly from the base and adapted to position a pack of wide mouth carryout bags above the base using the central, frangible mounting opening. First and second side mounting arms are provided. The first and second side mounting arms are attached to the central support. The first and second side mounting arms are adapted to engage the first and second dispenser arm mounting apertures, position a pack of wide mouth carryout bags above the base and to maintain the bags in an open position for loading.

The present invention is a significant inventive step over other self-opening bag packs. Rather than relying on the melding of bag surfaces together resulting from a blunt-tipped punch applied to the top of a corona-treated bag pack (Nguyen, U.S. Pat. No. 5,363,965), the present invention utilizes a uniform knife cut that passes entirely through the pack. In the Nguyen design, the first few bags in the pack will adhere together with a certain force. As bags are removed from the pack, the adherence of one bag wall to the next will be diminished in proportion to the depth of each bag in the pack. The further the bag is from the top of the pack, the less will be the adherence of each bag to the one below it in the pack. The bags of the present invention are adhered together using an elongated cut through the bag walls of a corona treated bag. In a given bag pack, the cut extends from the first bag in the pack through the last. As it is the cut edges of the bag walls that are adhered together, and as the cuts through each bag in the pack are uniform, the force to separate the first two bags in the pack will be substantially the same as the force to separate the last two bags in the pack.

An appreciation of the other aims and objectives of the present invention and an understanding of it may be achieved by referring to the accompanying drawings and the detailed description of a preferred embodiment.

