Web for fluid filled unit information

A web for the manufacture of fluid filled units with a novel machine and process is disclosed. The web includes an elongate heat sealable, flattened plastic tube comprised of face and back imperforate layers. The layers are imperforately joined together along spaced side edges. The layers include superposed longitudinal lines of weakness disposed generally transversely midway between the side edges. The web has longitudinally spaced, pairs of transverse seals. Each transverse seal extends from a respective side edge to an end near but spaced from the longitudinal lines of weakness. The transverse seal pairs include transverse lines of weakness extending from one side edge to the other generally centrally of each seal in a longitudinal direction. The side edges, transverse seals and lines of weakness together delineating two oppositely oriented strings of pouches with each pouch having three imperforate sides and a centrally located fill opening at its fourth side. The transverse lines of weakness are spaced slightly more than one half the circumference of a cylindrical fluid fill nozzle used to fill the pouches such that the web closely surrounds the nozzle during pouch fluid filling.

This invention relates to fluid filled units and more particularly to a novel and improved plastic web of interconnected pouches for use in a machine for, and with a process of, converting the pouches to fluid filled units.

BACKGROUND OF THE INVENTION

U.S. Pat. No. Re 36,501 reissued Jan. 18, 2000 and U.S. Pat. No. RE 36,759 reissued Jul. 4, 2000 respectively entitled “Method for Producing Inflated Dunnage” and “Inflated Dunnage and Method for its Production” and based on original patents respectively issued Sep. 3, 1996 and Dec. 2, 1997 to Gregory A. Hoover et al. (the Hoover Patents) disclose a method for producing dunnage utilizing preopened bags on a roll. The preopened bags utilized in the Hoover patents are of a type disclose in U.S. Pat. No. 3,254,828 issued Jun. 2, 1966 to Hershey Lerner and entitled “Flexible Container Strips” (the Autobag Patent). The preferred bags of the Hoover patents are unique in that the so called tack of outer bag surfaces is greater than the tack of the inner surfaces to facilitate bag opening while producing dunnage units which stick to one another when in use.

U.S. Pat. No. 6,199,349 issued Mar. 13, 2001 under the title Dunnage Material and Process (the Lerner Patent) discloses a chain of interconnected plastic pouches which are fed along a path of travel to a fill and seal station. As each pouch is positioned at the fill station the pouches are sequentially opened by directing a flow of air through a pouch fill opening to open and then fill the pouch. Each filled pouch is then sealed to create an hermetically closed, inflated dunnage unit. Improvements on the pouches of the Lerner Patent are disclose in copending applications Ser. No. 09/735,345 filed Dec. 12, 2000 and Ser. No. 09/979,256 filed Nov. 21, 2001 and respectively is entitled Dunnage Inflation (the Lerner Applications). The system of the Lerner Patent and Applications is not suitable for packaging liquids. Moreover, since the production of dunnage units by the process described is relatively slow, an accumulator is desirable. An improved accumulator and dispenser for receiving dunnage units manufactured by a dunnage unit formation machine is disclose in U.S. application Ser. No. 09/735,111 filed Dec. 12, 2000 by Rick S. Wehrmann under the title Apparatus and Process for Dispensing Dunnage.

Accordingly, it would be desirable to provide an improved system for filling pouches with fluid to produce dunnage or liquid filled units at high rates of speed.

SUMMARY OF THE INVENTION

The present invention is embodied in a plastic web which enhances the production of fluid filled units which may be dunnage units similar to those produced by the systems of the Lerner Patent and Applications but at greatly improved production rates. Specifically, a novel and improved unit formation web is disclose for use with a novel machine and process. The machine and process are claimed in a concurrently filed application Ser. No. 10/408,947 by Hershey Lerner et al, issued as U.S. Pat. No. 6,889,739.

The machine includes a rotatable drum having a spaced pair of cylindrically contoured surfaces. An elongated nozzle extends generally tangentially between and from the cylindrical surfaces. In use, the nozzle is inserted into the novel web at a transversely centered position as the web is fed upwardly and around the drum. The web has hermetically closed side edges and longitudinally space pairs of transverse seals. The seals of each pair are spaced a distance equal to slightly more than one half the circumference of the nozzle with which it is intended to be used.

Each transverse seal extends from an associated side seal toward the center of the web such that successive side seals and the associate side edge together define three sides of a pouch to be fluid filled. When the units being formed are dunnage, as the web passes over the nozzle, web pouches are inflated and the web is separated into two chains of inflated pouches as the nozzle assembly separates the web along longitudinal lines of weakness.

The chains are fed by the drum and metal transport belts successively under a plurality of heating and cooling shoes. Each shoe has a spaced pair of arcuate web transport belts engaging surfaces which are complemental with the cylindrical drum surfaces. The shoes are effective to clamp the transport belt and the web against the rotating drum as spaced sets of seals are formed to seal the air inflated pouches and convert the inflated pouches into dunnage units. The dunnage units are separated following their exit from the last of the cooling shoes.

Tests have shown that with pouches having four inch square external dimensions, dunnage units are produced at the rate of eight cubic feet per minute. This contrasts sharply with the machine of the Lerner Patents which produces dunnage units at the rate of three cubic feet per minute.

Accordingly the objects of the invention are to provide a novel and improved web for dunnage formation and a process of dunnage formation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the following description describes a dunnage formation system, it should be recognized the preferred embodiment of the machine is sterilzable so that beverages such as water and fruit juice may be packaged using the novel web, machine and process.

Referring now to the drawings andFIGS. 1 and 2in particular, a dunnage formation machine is shown generally at10. The machine includes a rotatable drum12which is driven by a motor14via a gear box15and a belt and pulley arrangement16, FIG.2. In the preferred and disclose arrangement, the drum is comprised of spaced annular disks18.

When the machine is in use a web20is fed from a supply, not shown. As is best seen inFIG. 1, the web20passes over a guide roll22and thence under a guide roll24to an inflation station25. The web20is fed around the disks18to pass under, in the disclose embodiment, three heat shoes26which shoes heat metal transport belts27to seal layers of the web. The heat softened web portions and the transport belts then pass under cooling shoes28which freeze the seals being formed. As the now inflated and sealed web passes from the cooling shoes individual dunnage units30are dispensed.

In practice the machine10will be housed within a cabinet which is not shown for clarity of illustration. The cabinet includes access doors with an electrical interlock. When the doors are open the machine may be jogged for set up, but the machine will not operate to produce dunnage units unless the doors are closed and latched.

The Web

Referring now toFIGS. 5-9, the novel and improved web for forming dunnage units is disclose. The web is formed of a heat sealable plastic such as polyethylene. The web includes superposed top and bottom layers connected together at spaced side edges32. Each of the side edges is a selected one of a fold or a seal such that the superposed layers are hermetically connected along the side edges32.

A plurality of transverse seal pairs34are provided. As best seen inFIGS. 5-7, each transverse seal extends from an associated side edge32toward a longitudinally extending pair of lines of weakness35. The longitudinal lines of weakness35are superposed one over the other in the top and bottom layers of the web and are located midway between the side edges. Each transverse seal34terminates in spaced relationship with the longitudinal lines of weakness which preferably are in the form of uniform, small perforations. The transverse seal pairs34together with the side edges32delineate two chains of centrally open side connected, inflatable pouches37.

As is best seen inFIGS. 7 and 8, transverse lines of weakness36are provided. The pouches are separable along the transverse lines36. Like the longitudinal lines of weakness35the transverse lines are preferably perforations but in contrast to the to the longitudinal line perforations each has substantial length. The perforations of the transverse lines36, in a further contrast with the perforations of the longitudinal lines35, are not of uniform dimension longitudinally of the lines. Rather, as is best seen inFIG. 8, a pair of small or short perforations38is provided in each line. The small perforations38of each pair are disposed on opposite sides of and closely spaced from the longitudinal lines34. Each transverse line of weakness also includes a pair of intermediate length perforations40which are spaced and positioned on opposite sides of the small perforations38. The intermediate perforations extend from unsealed portions of the superposed layers into the respective seals of the associated transverse seal pair. The remaining perforations of each line are longer than the intermediate perforations40.

The Machine

In the embodiment ofFIG. 1, the disks18are mounted on a tubular shaft42. The shaft42is journaled at44for rotation driven by the belt and pulley arrangement16. The shaft42carries a stationary, tubular, nozzle support45which extends from around the shaft42radially outwardly. A nozzle assembly46is carried by a support arm45A, FIG.6. The nozzle assembly46includes an inflation nozzle48. As is best seen inFIG. 6, the nozzle48is an elongated tube with a closed, generally conical, lead end portion49. The nozzle48when in use extends into the web at a central location transversely speaking. The web transverse lines of weakness are spaced slightly more than a one half the circumference of the nozzle so that the web layers fit closely around the nozzle to minimize leakage of air exiting side passages51of the nozzle to inflate the pouches37.

The nozzle assembly46includes a web retainer50which guides the web against the nozzle48. The retainer also functions to cause the web to be longitudinally split along the longitudinal lines of weakness35into two strips of inflated pouches.

As is best seen inFIGS. 3 and 3A, each of the heat shoes26has a mirror image pair of heat conductive bodies52. The bodies52together define a cylindrical aperture54, which houses a heating element, not shown. Each heat body52includes a seal leg55having an arcuate surface substantially complemental with a cylindrical surface of an associated one of the disks18. In the disclose embodiment the disk surfaces are defined by thermally conductive silicone rubber inserts18s, FIG.3A. In the embodiment ofFIGS. 3 and 3A, springs56bias the legs55against the transport belts27as the web passes under the heat shoes due to rotation of the drum12and its disks18. The cooling shoes38are mounted identically to the heat shoes.

Each cooling shoe28includes an expansion chamber58, FIG.4. An air supply, not shown, is connected to a chamber inlet60. Air under pressure is fed through the inlet60into the chamber58where the air expands absorbing heat and thus cooling the shoe. Exhaust air from the chamber passes through an exit62. Cooling shoe legs63are biased against the web to freeze the heat softened plastic and complete seals.

In the embodiment ofFIGS. 1-4cooling shoe exhaust air then passes through a conduit64to the tubular shaft42. Air from the cooling shoes is fed via the conduit64and the shaft42to a passage65in the nozzle support45. The passage65is connected to the nozzle48. Thus air from the cooling shoes is directed to and through the nozzle48and the exit passages51into the pouches.

With the now preferred and sterilizable embodiment, cooling shoes28′ as shown inFIG. 10are employed has a jacket67which surrounds a body having cooling fins shown in dotted lines in FIG.10. An inlet60′ is provided at the top of the jacket. Air flowing from the inlet passes over the fins cooling them and the exits from the bottom of the jacket. Each of the shoes28′ is vented to atmosphere through an outlet67. The nozzle48is directly connected to a supply of fluid under pressure and the shaft42may be made of solid material.

A pair of hold down belts66are mounted on a set of pulleys68. The belts66are reeved around a major portion of the disks18. As is best seen inFIGS. 3 and 3A, the belts66function to clamp portions of the web20against the disks on opposite sides of the shoe legs55. While test have shown that the machine is fully operable without the belts66, they are optionally provided to isolate pressurized air in the inflated pouches37from the heating and cooling shoes.

A fixed separator69is provided. As the inflated pouches approach the exit from the downstream cooling shoe the fixed separator functions to cam them radially outwardly sequentially to separate each dunnage unit from the next trailing unit along the connecting transverse line of weakness except for a small portion under the transport belts27.

A separator wheel74is provided, FIG.1. The wheel74is rotated clockwise as seen inFIG. 1such that arms76are effective to engage completed dunnage units30sequentially to complete the separation of each dunnage unit from the web along its trailing transverse line of weakness36. Thus, the separator wheel is effective to tear the last small connection of each pouch which was under an associated one of the transport belts as the pouch was substantially separated by the fixed separator69.

In the embodiment ofFIG. 1, each of the shoes26,28is mounted on an associated radially disposed shaft71. Clamping arrangements shown generally at72are provided to fix each of the shafts71in an adjusted position radially of and relative to the drum12. As is best seen inFIG. 3, each shaft71carries a yoke73. The springs56span between yoke pins75and shoe pins75to bias the shoes against a web20. A cylinder70is provided for elevating a connected yoke and shoe for machine set up and service.

In the now preferred embodiment ofFIG. 10, each shoe is pivotally mounted on an arm78. The arm is also pivotally mounted at80on a frame82. A cylinder70′ spans between the arm and the frame for elevating the connected shoe for set up and service and for urging the shoes28into their operating positions. The heat shoes26are, in the now preferred arrangement, identically mounted.

Operation

In operation, the shoes are elevated by energizing the cylinders70ofFIGS. 1 and 4or70′ ofFIG. 10. Aweb20is fed along a path of travel over the guide roll22and under the guide roll24and thence threaded over the inflation nozzle48. The web is then fed under the transport belts and the retainer50. As the machine is jogged to feed the web around the discs18and the heating and cooling shoes26,28the web is split by the nozzle support55. The split of the web is along the longitudinal line of weakness but the transverse lines of weakness remain intact at this time. Thus, the web portions at opposite ends of the small perforations38are of sufficient size and strength to avoid a longitudinal split of the web as the web is fed over the nozzle. Since the transverse seals of each pair are spaced only very slightly more than one half the circumference of the nozzle the web closely surrounds the nozzle to minimize air leakage when the pouches are inflated.

Next the heating and cooling shoes are elevated by actuating either the cylinders70or70′. The web is then fed sequentially, and one at a time, under the heating shoes26and the cooling shoes28. Since the web has been split by the nozzle support55, there are in fact two parallel paths of travel each with an associated transport belt27and chain of side connected and inflated pouches.

Once the web has been fed around the drum to an exit location near the separator wheel74and the machine has been jogged until the operator is satisfied the feed is complete and the machine is ready the heat shoe elements will be energized. Air will be supplied to the cooling shoes28and the nozzle48. Next the motor14will be energized to commence machine operation.

As we have suggested, one of the outstanding features of the invention is that the web closely surrounds and slides along the nozzle. The close surrounding is assured by the transverse seals being spaced a distance substantially equal to one half the circumference of the nozzle48. Thus, the two web layers together delineate a nozzle receiving space which will closely surround an inserted nozzle. As the web advances the pouches37on opposed sides of the nozzle will be filled efficiently by fluid under pressure exiting the nozzle passages51in opposed streams. Where dunnage units are being formed the fluid will be air. The web is then split by the nozzle support into two chains of side connected and fluid filled pouches respectively traveling along associated ones of the two paths of travel.

Each of the chains is fed under spaced legs55of the heating shoes26to effect heat seals. As the web passes under cooling shoe legs63the seals are frozen and the pouches are separated along most of the length of transverse lines of weakness by the separator. Facile separation is assured by the long perforations because the remaining connections of the web across the transverse seals are short in transverse dimension and few in number.

When the pouches exit the last of the cooling shoes, they have been formed into finished dunnage units30. The finished units30are sequentially completely separated from the web by the arms76of the separation wheel74.

While the system as disclosed and described in the detailed description is directed to dunnage, again, as previously indicated, units filled with fluids other than air such as water and fruit juices can be produced with the same machine, process and web.