KRISTAL, Boaz (57 Hasitvanit St, Zichron Yaakov, 30900, IL)
| CLAIMS A web of thermoplastic foils embedding a pattern of inflatable cushions having at least one longitudinal inflating channel through which a fluid for inflating said inflatable cushions is pressurized, wherein at least one of said inflatable cushions is fluid connected to said inflating channel by means of a feeding aperture which separates between two segments of an intermittent seam, wherein said intermittent seam separating between the lumen of said inflating channel and the lumen of said at least one inflatable cushion, said web of foils comprising: • a plurality of inflating apertures axially disposed along a wall of said at least one inflating channel, for receiving said fluid into said at least one inflating channel; • a longitudinal seam shaped as a dotted line disposed between said intermittent seam and the axis of said inflating channel, wherein said longitudinal seam divides the lumen of said inflating channel into distinct portions, one of which provides for inserting a guiding shaft therein for retaining at least a portion of said web of thermoplastic foils stretched relative to said inflating channel, and • an inlet pan associated with said feeding aperture, wherein said inlet pan comprises at least one spacing separating between members selected from a group of members consisting of two adjacent dot like seams closely disposed by said feeding aperture, a dot like seam and a segment of said intermittent seam each of which disposed adjacent to said feeding aperture. 2. A web of thermoplastic foils as in claim 1 , wherein said feeding aperture comprises more than one passageway. 3. A web of thermoplastic foils as in claim 1 , further comprising at least two inflatable cushions, and wherein said at least two inflatable cushions are interconnected by means of a connecting aperture, and wherein said connecting aperture comprises more than one passageway. 4. A web of thermoplastic foils as in claim 1 , wherein said intermittent seam is the first intermittent seam, and wherein said at least one inflating channel medially disposed within said web of thermoplastic foils, and wherein a second intermittent seam which is different from said first intermittent seam disposed at a side which is the opposing side of said inflating channel in which said first intermittent seam is disposed. 5. A web of thermoplastic foils as in claim 4, wherein said at least one of said inflatable cushions which is the first inflatable cushion disposed at one side of said at least one inflating channel, and wherein another of said inflatable cushions which is different from said first inflatable cushion disposed at the opposite side of said at least one inflating channel. 6. A web of thermoplastic foils as in claim 5, wherein said longitudinal seam is the first longitudinal seam, and wherein a second longitudinal seam which is different from said first longitudinal seam inwardly disposed within said at least one inflating channel along a line disposed closer to said second intermittent seam. A web of thermoplastic foils as in claim 1 , wherein said inflating channel is the first inflating channel, and wherein said web of thermoplastic foils further comprising at least a second inflating channel which is different from said first inflating channel, and wherein at least one of said inflatable cushions fluid connected to each of said first inflating channel and said second inflating channel. A web of thermoplastic foils such as in claim 1 , wherein a perforated line separates between two of said inflatable cushions. A web of thermoplastic foils such as in claim 1 , wherein said fluid is characterized by a state of aggregation selected from a group of states of aggregation consisting of gases, liquids, and gels. 10. A device for inflating and sealing inflatable cushions embedded in a web of thermoplastic foils having at least one inflating channel through which a fluid is driven to inflate at least one of said inflatable cushions, said device has a tubular enclosure along which said at least one inflating channel is advanced, said device comprising: • a guiding shaft insertable into said inflating channel for retaining said web of thermoplastic foils stretched relative to said tubular enclosure; • at least one blocking mechanism structured and arranged for blocking the translational motion of said guiding shaft along with said advancing inflating channel, and wherein a plurality of inflating apertures axially disposed along a wall of said at least one inflating channel. A device as in claim 10, further comprising at least one soldering head, which is the first soldering head, and wherein said first soldering head comprises an active face, which is the first active face, and wherein said active face alternately presses against contours disposed across a surface of said web of thermoplastic foils for heat soldering seams confined within said contours. A device as in claim 11 , wherein said at least one soldering head comprises a pressing member such structured and arranged that said pressing member starts pressing at the margin of any of said contours a while before said active face starts pressing against the surface of said web of thermoplastic foils confined within said contour. 13. A device as in claim 10, wherein said tubular enclosure is the first tubular enclosure, and wherein said guiding shaft is the first guiding shaft, and wherein said device further comprising: • at least one additional tubular enclosure that is different from said first tubular enclosure, and • at least one additional guiding shaft that is different from said first guiding shaft, and wherein said second guiding shaft provides for retaining a portion of said web of thermoplastic foils stretched between said first tubular enclosure and said second tubular enclosure. A device as in claim 10, further comprising a heater having an arcuate body, and wherein said arcuate body comprises grooves, and wherein said active face comprises prisms protruding off said active face, and wherein the widths of said prisms respectively conform to the widths of said grooves. A device as in claim 10, wherein said fluid is characterized by a state of aggregation selected from a group of states of aggregation consisting of gases, liquids, and gels. A device such as in claim 11 , further comprising at least another soldering head which is the second soldering head and which is different from said first soldering head, and wherein said second soldering head comprises an active face which is the second active face, and wherein said second active face alternately presses against contours disposed across a surface of said web of thermoplastic foils. A device such as in claim 16, wherein the distance between two adjacent footprints of said first active face across said web of thermoplastic foils equals the distance between two adjacent footprints of said second active face across said web of thermoplastic foils. A device such as in claim 16, wherein the distance between two adjacent footprints of said first active face across said web of thermoplastic foils is different compared to the distance between two adjacent footprints of said second active face across said web of thermoplastic foils. A device such as in claim 16, further comprising at least another soldering head which is the third soldering head, and wherein said third soldering head comprises an active face, which is the third active face, and wherein said third active face alternately presses against contours disposed across a surface of said web of thermoplastic foils, and wherein said third soldering head is different from said first and second soldering heads, and wherein the distance between two adjacent footprints of said third active face across said web of thermoplastic foils is different compared to the distance between two adjacent footprints of said first active face across said web of thermoplastic foils. 20. A device such as in claim 19, wherein the distance between two adjacent footprints of said third active face across said web of thermoplastic foils is different compared to the distance between two adjacent footprints of said second active face across said web of thermoplastic foils. |
FIELD OF THE INVENTION
The present invention relates to inflatable cushions and a device for inflating and sealing such inflatable cushions.
BACKGROUND OF THE INVENTION
Inflatable cushions made of thin films of thermoplastic materials that are typically filled with air are normally utilized for protecting packaged goods during shipping and/or storage. Exemplary inflatable cushions that are available in the marketplace are provided with valves such that they can be manually inflated up to a desired level pressure. However the rate by which these cushions can be manually inflated might not suffices in cases in which a relatively heavy load of packaging is considered. Therefore devices for inflating and sealing cushions that provide for preparing in situ a considerable amount of inflated cushions at permissible production rates and costs have been developed.
Exemplary inflating and sealing device is disclosed in US patent US7048025. This device is fed with a web of foils in which a pattern of spaced apart inflatable cushions is embedded. Each inflatable cushion of this web of foils has an inflating conduit having an inlet connecting aperture and a relatively narrow throat. The foil is intermittently propagated through the disclosed device such that one side of the inflating conduit of the current cushion is engaged by the surface of a groove disposed on a face of an anvil. The inlet connecting aperture disposed on the other side of the inflating conduit in engaged by a cap circumferential to the outlet of the inflating tube and sealing bar of the disclosed device. Positioning the current cushion in place is assisted by means of a suctioning tube of the disclosed device. A fluid such as air is pressurized at this stage through the inflating tube into the conduit and thereby into the lumen of the cushion considered. The sealing bar provides for electrically connecting a resistance wire embedded in the wall of the inflating conduit to a source of electrical current, such that the inflating connecting aperture of the cushion is sealed off by means of heat soldering. The inventors of the disclosed device report that the rate by which cushions are inflated and further sealed off by means of the disclosed device is significantly higher compared to rates achievable by means of other devices that were commercially available at the time in which the patent application considered was filed. However the resistance wire utilized increases the production cost of the web of foils considered. Furthermore employing vacuum means for positioning a current inflated cushion in place limits the production rate and complicates the inflating process.
Another exemplary device for inflating and sealing cushions embedded in a web of foils is disclosed in US patent US7361397. The web of foils considered includes a pattern of spaced apart inflatable cushions. Similarly to the process described above, inflating the cushions with gas such as air and sealing them off is effected by means of the disclosed device while the web of foils is propagated through it. The foil considered includes an inflating channel disposed along one side of the film. An inflating port connects each of the embedded cushions to the inflating channel. A matching outlet port disposed at the opposite side of the wall of the inflating channel provides for retaining the pressure of the gas within each inflated cushion below a predfined pressure level. The disclosed device has an inflating tube that is introduced into the inflating channel such that a segment of the tube disposed close to its open end is enclosed within the inflating channel. Gas delivered by the inflating tube provides for inflating each cushion the inflating port of which disposed within a specified range by the open end of the inflating tube. A blade disposed at the other end of this segment of the inflating tube provides for cutting the wall of the inflating channel, such that the considered segment of the tube provides for guiding the advanced web of foils, such that it can be continuously propagated along this segment of inflating tube. However the blade that cuts the inflating channel may get blunted through cutting. Therefore corrective maintenance action for replacing a blunt blade is occasionally required. Otherwise the foil is eventually dragged and torn up rather than being sharply cut off, thereby messing up the progress of the foil through the inflating and sealing device and the production process.
Therefore an inflating and sealing device providing for reliably inflating cushions of various shapes and sizes and sealing them off in situ, at a relatively high rate is beneficial.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an elevational view of a segment of exemplary web of foils in which a pattern of inflatable cushions is embedded according to an embodiment of the invention;
Fig. 2 is an isometric view of a segment of a device for inflating and sealing cushions according to a preferred embodiment of the present invention;
Fig. 3 is an elevational view of a segment of the web of foils shown in
Fig. 1 in which a number of rows including inflated and sealed off cushions, another row of cushions is being inflated before it is being sealed off and the rest of the rows shown are at a stage prior to being inflated by a device such as shown in Fig. 2;
Fig. 4 is an isometric view of a segment of the device shown in Fig. 2;
Fig. 5a - 5b are elevational views of two guiding shafts of a device for inflating and sealing inflatable cushions according to two different embodiments of the present invention respectively;
Fig. 6 is an isometric view of another segment of the device shown in Fig. 2; Fig. 7 is an isometric view of a detail of the device shown in Fig. 2;
Fig. 8 is an isometric view of a device for inflating and sealing inflatable cushions according to an embodiment of the present invention;
Figs 9a - 9b are elevational views of two segments of webs of thermoplastic foils that are suitable for being inflated and sealed by means of a device of the invention in which different patterns of inflatable cushions are respectively embedded.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
In accordance with the present invention a device for inflating and sealing inflatable cushions embedded in webs of foils of thermoplastic materials as well as webs of thermoplastic foils embedding inflatable cushions are provided. A web of thermoplastic foils that is suitable for being inflated and sealed off such as by a device of the invention has one or more inflating channels each of which has a plurality of inflating apertures disposed across its sidewall. At least one seam disposed at the edge of an inflating channel is intermittent. A spacing separating between two adjacent segments of such intermittent seam forms a feeding aperture. A feeding aperture connects between the lumen of the inflating channel and the lumen of an adjacent inflatable cushion. Additional seam that looks like a dotted line inwardly disposed relative to the above mentioned intermittent seam. A number of dots adjacent to a feeding aperture provide for generating a few passageways leading inflating fluid from the lumen of the inflating channel into the feeding aperture considered. Therefore a relatively wide inlet pan is formed adjacent to each feeding aperture for enhancing the rate of flow of inflating fluid into the currently inflated cushion as further described infra. The inflating channels of a web of foils provide for inflating the embedded cushions as well as for guiding the web of foils and stretching it while it is progressed through the device of the invention. A web of foils of the invention may have an inflating channel that feeds with inflating fluid inflatable cushions that are laterally disposed at each of the two sides of the inflating channel considered. Alternatively a web of foils of the invention may have at least two different inflating channels and at least one inflatable cushion that is fluid connected to both of these inflating channels. A row of inflatable cushions of a web of foils that are interconnected among themselves can be concomitantly inflated by means of these two different inflating channels. Typically, cushions that are arranged in a two dimensional array within the web of foils of the invention are interleaved. Namely, any line drawn across a mid-plane disposed inbetween the foils considered passes through sidewalls of more than one inflated cushion. Therefore sharp edges or corners of the goods their packaging lined with such inflated web of foils are practically lined with pressurized cushions. Additionally, inflated cushions that are arranged in a two dimensional array within a web of foils of the invention can be individually sealed off such that in a case in which a wall of a single cushion is punctured the adjacent cushions remain intact and continue retaining the same level of inner pressure of the inflating fluid contained therein. Reference is now made to Figs 1 - 3. An elevational view of a segment of an exemplary web of thermoplastic foils of the invention in which hexagonal cushions are embedded is shown in Fig. 1. Web of foils 9 is made of two foils of a thermoplastic material 10 and 11 that are mutually adhered by means of a suitable adhesive and/or heat soldered one to the other along seams such as seams 12. The footprint of seam 12 across the inner surface of foil 11 is schematically presented by dashed line designated by 13. Rows of densely packed and interleaved hexagonal cushions are generated by seams 12. Web of foils of the invention 9 is characterized by the densely packed array of cushions consisting of rows successively arranged in which cushions of adjacent rows are interleaved. Namely, any line that is parallel to the plane of foil 10 disposed in between planes 10 and 11 that crosses a sidewall of a cushion also crosses the wall disposed at the opposite side of the same cushion, as well as the sidewalls of at least a number of additional different cushions. Connecting apertures 16 provide for interconnecting all the cushions arranged along one row, such that their lumens form continuum. Each of the connecting apertures 16 is formed by an intermittent seam that separates between two adjacent inflatable cushions. Feeding apertures 17 connects between the lumen of inflating channel 18 and the lumens of the outermost cushions of each row that are located adjacent to inflating channel 18. Any of feeding apertures 17 provides for simultaneously feeding a row of interconnected cushions with the inflating fluid considered. Similarly feeding apertures 17' connects between the lumen of outermost cushions disposed at the opposite sides of each row and inflating channel 18' that is disposed at the opposite side of the web of foils. Feeding apertures 17, 17" are respectively formed by intermittent seams that separate between the lumen of an outermost inflatable cushion of a row of cushions and the lumen of the inflating channel considered. Heat soldered or adhered dots 20 collectively form a longitudinal seam shaped as a dotted line. Continuous seam 21 seals off the lumen of inflating channel 18 at the opposite side of the intermittent seam that separates between the inflating channel and the adjacent inflatable cushions. Similar continuous linear seam 21" and a longitudinal seam shaped such a doted line (that includes dots such dote 20') delimits the volume of the major portion of the lumen of inflating channel 18" disposed at the opposite side of web of foils 9. This major portion of the inflating channel provides for introducing a guiding shaft of the device for inflating and sealing inflatable cushions as further described infra. Webs of foils in which a single segment of foil that is heat soldered only along the doted line that includes dots 20 or 20' may implement according to the present invention inflating channel 18 or 18" as well. A plurality of inflating apertures such as inflating apertures 22 and/or 22' axially disposed along the wall of inflating channels 18, 18' provide for pressurizing fluid such as air into the lumen of inflating channel 18 and/or 18', thereby concomitantly pressurizing fluid into cushions of the same row that are fluid connected to the lumen of inflating channel 18 and/or 18'. The spacing disposed in between any of the intermittent seams along which feeding apertures 17, 17' are respectively disposed and a number of adjacent soldered or adhered dots 20, 20' forms a relatively wide inlet pan associated with the feeding aperture considered. Such inlet pan provides for efficiently deriving the inflating fluid through to pressurize an array of interconnected inflatable cushions. Thereby the rate of flow of the inflating fluid considered into an array of interconnected inflatable cushions that is fed by a respective feeding aperture is significantly enhanced. Therefore an enhanced production rate of inflated and sealed cushions can be achieved. In Fig. 2 segment 30 of a device for inflating and sealing cushions according to a preferred embodiment of the present invention is shown. Web of thermoplastic foils 32 is introduced into device 30 such that its inflating channel 34 is enclosed within a dedicated tubular enclosure: This tubular enclosure is such structured and arranged that a track along which the respective inflating channel of a web of foils to be processed is formed. A guiding shaft, not shown, enclosed within the lumen of inflating channel 34 that occupies this enclosure provide for stretching web of foils 32 and keeping it in track while is continuously progressed through device 30 along the direction indicated by arrow 35. An optional gripping mechanism disposed at the rim of each aperture of the tubular enclosure, not shown, automatically presses the wall of the inflating channel towards the body of the guiding shaft. Such pressing provides for sealing off the lumen of the tubular enclosure. The sealed enclosure provides for building up the required pressure for efficiently inflating the inflatable cushions. The web of foils is progressed by rotating both puling wheels 36 in opposite directions. Both pulling wheels are encompassed with band made of soft material such as rubber. Both pulling wheels are pressed against each other to sandwich web of foils 32 in between them. Fluid such air compressed by means of a blower is delivered into inflating chamber 38 by means of a pipe, not shown, that is connected to inlet connector 39. Intermittently and synchronously soldering head 42 and supporting head 42A are rotated by 180° (along a semi circle) in opposing directions. During such rotation a segment of the web of foils is pressed against contours disposed across opposing surfaces of the web of foils while being sandwiched by the active face of supporting head 42A and an active face of soldering head 42. Thereby a seam is heat soldered within the volume confined by such contours to seal the respective connecting aperture that previously connected between a cushion considered and the inflating channel. Alternately, pulling the web of foils can be accomplished according to a different embodiment of the present invention by means of clamping fingers as known. The rotation of the soldering heads can be synchronized with the rotation of pulling wheels 36 such that the current connecting aperture to be heat soldered will face the rotating soldering head. Synchronizing the progress of the foils and the rotational motion of the soldering heads can be achieved by means of cogwheels as shown and or by means of belts and a suitable gearbox. Alternatively, in accordance with another embodiment of the present invention, a soldering head as well as the respective supporting head are linearly translated back and forth along a line perpendicular to the web of foils considered. For sealing a connecting aperture by heat soldering the soldering head and the respective supporting head are translated towards the web of foils to press it while it is sandwiched between them. By the end of such heat soldering phase that takes a predefined time interval both soldering head and the respective supporting head are translated off the web of foils, such that the web of foils is free to progress along the direction indicated by means of arrow 35.
The guiding shaft that provides for stretching the web of foils relative to the tubular enclosure of the device of the invention is free to move relative to the device for inflating and sealing inflatable cushions of the invention and is definitely not connected to this device. A pair of ball bearing implements blocking mechanism 44 for keeping the enclosed guiding shaft in a fixed location relative to the progressing inflating channel and preventing any translational motion of the guiding shaft along the tubular enclosure with the advancing web of foils 32. Optional biasing springs, not shown, respectively force each of the ball bearings towards the respective surface of the inflating channel. A portion of the fluid that is pressurized into the inflating channel always keeps flowing towards both sides axially with the direction of the guiding shaft for cooling off the walls of the inflating channel.
Arcuate heater 46 is provided with embedded electrical heaters and suitable temperature control circuitry. The electrical heaters and circuits are respectively contained within two cylindrical cavities, such as cavity 48. The cavities are structured in two prisms respectively disposed at both opposing sides of heater 46. Heater 46 provides for retaining the active faces of the soldering heads at a predefined temperature, as further described infra. In Fig. 3 a segment of the same web of thermoplastic foils shown in
Fig. 1 is shown at an intermediate stage while is being processed by means of the inflating and sealing device a segment of which is shown in Fig. 2. Web of foils 32 has inflating channel 34 that is structured and arranged for housing a guiding shaft, not shown. Perforations such as inflating apertures 52 disposed along the sidewall of inflating channel 34 provide for pressurizing a fluid such as air into inflating channel 34 and further into the inflatable cushions embedded in the web of foils 32. Seams 56 are heat soldered by means of the soldering head of the device described with reference to Fig. 2 hereinabove to seal a respective feeding aperture thereby forming a continuous row of inflated cushions 58. Such are the cushions arranged along row 62 each of which is pressurized with inflating fluid and is ready to be sealed off. Seams 60 linearly disposed along such row are further heat soldered for individually sealing each of the interconnected cushions. Heat soldering is effected by means of an array of soldering heads, not shown, that is further described below. Sealing off is accomplished by successively heat soldering the respective connecting apertures 66 that are fluid connected to feeding aperture 64 that currently faces the respective soldering head. Sealing off a respective feeding aperture is synchronously effected with heat soldering to seal off all the connecting apertures 66 of the current row of cushions that is inflated by the feeding aperture considered. Cushions arranged along row 68 are still deflated as the respective feeding aperture 65 has not entered the inflating chamber yet.
Optionally the connecting apertures and/or the feeding apertures of a web of foils of the invention are divided to two or more passageways by means of one or more dots in which the external foils are mutually adhered, or heat soldered to each other. These dots are generated at the stage in which the web of foils is manufactured prior to the stage in which it is processed for inflating and sealing the cushions. Such dots effectively shorten the length of a seam that seals off the respective connecting or feeding aperture. The inner surfaces of the external foils utilized for manufacturing the web of foils in which a pattern of inflatable cushions is embedded comprises a heat sealable thermoplastic material. Exemplary are co-extruded foils one layer of which is made of low density polyethylene whereas the other layer is made of high density polyethylene. The inner layer of one or both external foils is typically made of a thermoplastic material that is more easily heat soldered. Whereas the external layer is made of thermoplastic material that can better sustain harsh environmental conditions. By shortening the lengths of seams that seal off the pressurized cushions the chances for generating folds of the external foil while is being stretched out are significantly reduced. Reference is now made to Figs 4 - 7 in which further aspects of a device for inflating and sealing cushions of the invention are shown. In Fig. 4 a segment of the device shown in Fig. 2 is shown in more details. Web of foils 70 is introduced into segment 72 of the device for inflating and sealing cushions shown in Fig. 2. Inflating channel 74 encloses guiding shaft 76 that is inserted into tubular channel 78 that is located in front of the inflating chamber, not shown. Two ball bearings 80 press against opposing surfaces of the inflating channel, thereby blocking the translational motion of guiding shaft 76 in parallel with web of foils 70. In Fig. 5a guiding shaft 84 of a device for inflating and sealing cushions according to a preferred embodiment of the present invention is shown. Guiding shaft 84 has two tapered ends such as end 86. Circular grooves such as grooves 88 are disposed across the cylindrical body of guiding shaft 84. These grooves provide for fluid connecting the inflating connecting apertures disposed on the sidewall of inflating channels of web of foils of the invention with the spacing that separate between adjacent soldered dots along the seam that separates between the inflating channel and the body of the web of foils. In Fig. 5b guiding shaft 90 of a devise for inflating and sealing cushions according to another embodiment of the present invention is shown. Oval groove 92 fits in with the curvature of the ball bearing of the device, such that guiding shaft 90 is fixed in place after being introduced into the inflating channel and placed within the tubular enclosure of the device considered. Circular grooves disposed across the surface of the cylindrical body of guiding shaft 90, or array of bores drilled through the cylindrical body, not shown, provide for fluid connection between the inflating connecting apertures disposed at the surface of the inflating channel and the spacing disposed along the seam that separates the inflating channel from the body of the web of foils.
In Fig. 6 a soldering head 110 of a device for inflating and sealing cushions shown in Fig. 2 is shown at a stage in which the connecting aperture connecting between the lumen of cushion 112 that is closely disposed to inflating channel 114 of web of foils 116. Soldering head 110 has two molding members 118 respectively having active face 120 each. One of these active faces is shown while is pressing against web of foils 116 at the very location in which the respective connecting aperture to be currently sealed off is placed. The other active face is disposed at the opposite side relative to the axis around which the soldering head rotates such that it points away from the web of foils. A number of elongated bulges structured such as prisms protrude off the active faces of both molding members. The reduced area of these prisms provide for enhancing the pressure exerted onto the layered thermoplastic foils. The molding members and the prisms of their active faces are typically made of metal such as copper, bronze or titanium. These prisms are retained at a predefined temperature that is close to, and below the melting point of the thermoplastic material considered. Resilient pressing member 122 that is typically made of silicone rubber or polyurethane is respectively attached to each pressing member such that its free end extends a bit beyond the active face of the respective molding member. Supporting head 124 that synchronously rotates with the soldering head at the same rotational speed and towards the opposite direction is shown such positioned that one of its active faces presses against the surface of the web of foils at the opposite side relative to the surface onto which the active face of the molding member currently presses. The other active face of supporting head 124 is designated by 126 points away from the web of foils. Both active faces of the supporting head are covered with relatively soft material such as silicon that is preferably covered with a foil of Teflon.
A method and system providing for configurationally heat soldering layered thermoplastic foils is disclosed in international patent application PCT/IL09/001072. In accordance with the disclosed method predefined contours across a surface of layered thermoplastic foils are pressed between a plurality of fingers of a predefined temperature disposed on an active face of a soldering head and a supporting surface. Heat is conducted from the active face of the soldering head into the layered foils concomitantly with the pressing. As a result of the transferred heat the utmost layer or_ layers that are close to the active face fuse. Then the layered foils are mutually attached by the pressing. It is preferable according to the disclosed method to press against the margin of a heated contour disposed across the layered thermoplastic foils before the heating starts and to continue pressing a while after heating is stopped. Therefore whenever the soldering head is rotated, say in the direction shown by curved arrow 128 the respective pressing member first presses the web of foils against the respective supporting surface. The active face of the molding member follows pressing near by a while later concomitantly with heating the sandwiched thermoplastic foils across the footprints of the prisms of the molding member. The pressing member continues pressing at the margin of the newly formed seam a while after the molding member is such rotated that it is removed off the surface of the web of foils. When a rotation by 180° is accomplished both the soldering head and supporting head are such positioned that both heads are directed in parallel to the web of foils. A new cycle in which both heads will respectively rotate towards the same directions at the same rotational speed by another 180° will start after the web of foils will be such progressed that feeding aperture 132 will replace the feeding aperture that is currently shown being heat soldered. At this stage feeding aperture 134 will replace feeding aperture 132 providing for inflating the respective cushion its lumen is accessed through feeding aperture 132.
A segment of arcuate heater 46 of the device shown in Fig. 2 is shown in details in Fig. 7. Longitudinal grooves 140 compliant with the dimensions, such as widths, and the geometrical shapes of the prisms protruding off the active face of molding member 142 are structured on the inner face of arcuate heater 46. The respective pressing member is not shown in Fig. 7. These grooves provide good thermal connection between the body of arcuate heater 46 and the prisms disposed on the respective active face of a soldering head. The temperature of the arcuate heater is regulated at a predefined level by means of electric heaters and a suitable electric circuit embedded in housing 144. Both such housings are symmetrically disposed at both ends of arcuate heater 46. Therefore whenever the revolving soldering heads are such positioned that the prisms of an active face are engaged with the respective grooves of the heater they are. heated up to the temperature of the heater. The grooves of the heater further provide for removing leftover of thermoplastic material that might get stuck to the active faces of the soldering head. Obviously such heating mechanism avoids faults that might occur when electrical touch contacts such as usually employed for delivering electrical 5 current to revolving electrical heaters are employed. However there are embodiment variants of the present invention in which electrical heaters are embedded in the prisms of the rotating molding members, or the within the alternative translating soldering heads described hereinabove, such that the arcuate heater can be avoided.
10 Reference is now made to Fig. 8 in which device 160 for inflating and sealing inflatable cushions according to an embodiment of the present invention is shown. Web of foils 162 is shown while its both inflating channels, such as inflating channel 164, are introduced through tubular inflating and guiding enclosures that are respectively housed in two inflating units such as unit 166. i s A pair of pulling wheels similar to those described hereinabove that are housed within unit 166 provide for continuously pulling web of foils 162 through device 160 at a relatively fixed translational speed. Soldering heads such as heads 168 provide for sealing the feeding apertures connecting between the inflating channels and the respective outermost cushions of a respective row of
20 successively arranged cushions. Heaters' housings such as housing 170 enclose electrical heaters for heating soldering heads 168. The arcuate bodies of the heaters that include the grooves described above are not shown. Supporting heads, such as heads 172, are placed at the other side of the web of foils, such that when are synchronously rotated with these soldering heads
25 they press against the web of foils sandwiched in-between. Elongated shaft 174 carries a plurality of soldering heads having interleaved molding members 176. Molding members 176 are such arranged that any plane passing through one molding member passes only through this very molding member. Molding members 176 alternately extend to opposing sides of the shaft. Note that
30 soldering heads 168 have two molding members extending towards opposing directions both of them are included in one plane. When the elongated shaft carrying molding members 176 completes full rotation of 360° each molding member, any of those of soldering heads 168 and/or any of molding members 176 presses only once the web of foils. However each footprint of any of molding members 176 is spaced apart from the previous footprint by a distance that is larger compared to the distance separating between successive
5 footprints of the molding members of soldering heads 168. Slots 178 structured on elongated heaters 180 and 182 provide for heating the respective molding members 176 when are engaged with them. Shaft 184 carries a plurality of supporting heads that provide for supporting the web of foils against the pressing of a respective molding member of the plurality of molding members l o 176. The rotational speed of shaft 174 that carries the soldering heads as well as the rotational speed of shaft 184 that carries the supporting heads alternately varies according to a preferred embodiment of the present invention. Any rotation of both shafts by 360° is accomplished by twice synchronously rotating both shafts along a semicircle (by an angle of 180°). Each of such
15 rotations along a semicircle is such accomplished: first both shafts 174 and 184 stay motionless along a first time interval along which the web of foils progresses along most of the distance separating between the axes of two successive feeding apertures 189. At the suitable point in time in which the first end of an feeding aperture 189 gets close enough to the outermost end of the
20 footprint of the respective molding member across the web of foils, both shafts are rotated at opposing rotational angles at a considerably high rotational speed, such that the active faces of a soldering head and a supporting head concomitantly start pressing the sandwiched web of foils synchronized with the translational motion of the web of foils. Initiating such fast rotations along a
25 semicircle is typically accomplished by tracking the translational motion of the web of foils.
Alternatively, all the soldering heads as well as all of the supporting heads of a device for inflating and sealing inflatable cushions in accordance with another embodiment of the present invention, are structured and arranged 30 to linearly and independently translate back and forth in a direction that is perpendicular to the web of foils. Any of the soldering heads is provided with an individual electric heater that is respectively activated by means of an electric current of a predefined level for a predefined time interval, such that the quantity of heat conducted to the sandwiched web of foils is confined within a predefined range of heat levels. Optionally the temperature of the active faces of a selected number of soldering head is measured to provide for regulating the level of electric power intermittently delivered to the soldering head considered. For sealing off any of the connecting apertures through which the inflating fluid gets into the lumen of an inflatable cushion embedded in the web of foils, the respective pair of soldering head and supporting head concomitantly moves towards the respective surface of the web of foils. The respective heater is synchronously activated while the respective soldering head and supporting head press against both opposing surfaces of the sandwiched web of foils. Such pressing is synchronously activated at the suitable point in time in which the connecting aperture considered reaches the projection of the soldering head on the plane containing a surface of the web of foils while is progressing through the device for inflating and sealing inflatable cushions. The soldering heads and the respective supporting heads are such arranged in a two dimensional array that complies with the positions of the connecting apertures of the inflatable cushions to be sealed off. Inflatable cushions embedded in the web of foils considered need not be of the same geometrical shape or the same dimensions, as long as the positions of the various pairs of soldering heads and supporting heads comply with the planar distribution of the connecting apertures to be such heat soldered. The planar distribution of connecting apertures associated with webs of foils in which a pattern of interleaved cushions all of which have the same shape is embedded is characterized by two different distances that separate between adjacent connecting apertures. In cases in which the web of foils considered embeds cushions having a variety of geometrical shapes and/or dimensions the planar distribution of the connecting apertures across the surface of the web of foils is characterized by more than two different distances that separate between adjacent connecting apertures, or adjacent footprints of the soldering heads across the surface of the web of foils.
Alternatively, a plurality of segments of the external surface of the web of plastic foils each of which located adjacent to a respective connecting or feeding aperture are suitably marked or colored. Such marking provides for optically tracking the translation of the web of foils through a device for inflating and sealing inflatable cushions accord/ng to another embodiment of the present invention. Thereby the motion of the respective soldering heads is synchronized with the momentary location of the respective segment to be currently heat soldered. The rotating soldering heads are suitably rotated right in time when the respective row of inflatable cushions gets to the right position such that the soldering head will press the sandwiched web of foils to heat solder the respective feeding and/or connecting apertures of the row considered. Heating and pressing the sandwiched web of foils need not be concomitantly accomplished. According to another embodiment of the present invention heating the segments of web of foils disposed along a row is effected by blowing heated air towards the marked contours. Only the respective segments of the web of foils which are such heated are fused whereas the temperature of the surrounding area remain significantly lower. Then the respective segments disposed across both faces of the web of foils are further adhered to each other while are jointly pressed by means of the respective soldering heads.
The devices for inflating and sealing inflatable cushions as described hereinabove provide for sealing any individual cushion regardless of its geometrical shape or dimensions, such that in a case in which any of the cushions of a web considered is punctured the neighboring cushions remain inflated and pressurized at the same original level of pressure.
Typically, a web of foils of the invention embeds a multiplicity of groups each of which includes a number of inflatable cushions which are fluid interconnected among them. Therefore all the cushions of such group are simultaneously inflated. Web of foils of the invention may include one, two or more inflating channels. Contrary to common web of foils embedding pattern of inflatable cushions, web of foils of the present invention that include only one inflating channel may have at least two arrays of inflatable cushions axially arranged along both opposing sides of the inflating channel considered. This inflating channel is internally disposed within the web of foils. Therefore inflating cushions disposed at opposing sides of this inflating channel simultaneously occurs. Webs of foils having two or more inflating channels include groups of cushions that are concomitantly inflated by means of more than one inflating channel. Inflatable cushions of a group of interconnected cushions may have a variety of different geometrical shapes. Similarly the dimensions of inflatable cushions of a group of interconnected cushions need not be identical respectively. All the cushions of such group are successively arranged laterally with the axis of the web of foils and are fluid connected to an inflating channel that is disposed adjacent to the outermost cushion of this group.
Reference is now made to Figs 9a-9b. In Fig. 9a a segment of web of foils in accordance with an embodiment of the present invention is shown. Web of foils 190 has two inflating channels, such as inflating channel 192 that is axially disposed along one of its sides. Inflating apertures 194 are disposed across the sidewall of inflating channel 192. Linear arrays of cushions the geometrical shape of which is of a curved rhombus, such as arrays 196 are fluid connected to inflating channel 192 by means of connecting apertures such as connecting aperture 199. Groups containing a number of cushions that are arranged in a linear array are interconnected by connecting apertures such as connecting apertures 199. Web of foils 190 after being inflated and its cushions individually sealed is relatively immune to punctures. Namely in a case in which a cushion is accidentally punctured the neighboring cushions remain inflated and pressurized. The seams that form the pattern of the cushions such as seam 200 and or the seams that form the inlet connecting apertures to the linear arrays of the cushions such as seams 201 , can be made by configurationally heat soldering as described in international patent application its number is PCT/IL09/001072. In Fig. 9b a web of foils in which a pattern of inflatable cushions is embedded according to another embodiment of the present invention is shown. Web of foils 210 has a single medial inflating channel 212 that is axially disposed. Inflating apertures 214 are axially disposed along the surface of inflating channel 212. Arrays of inflatable cushions, such as array 216, each of which includes a single cushion that is fluid connected to inflating channel 212 by means of a respective feeding aperture, such as feeding aperture 218. Perforations such as perforations 220 provide for separating and removing individual cushions off the web of foils as known.
Any one who is familiar with the art may understand that devices as described hereinabove or similar devices can be employed for processing webs having three or more inflating channels, as well as webs including cushions having different geometrical shapes and/or dimensions. The number of axially disposed and spaced apart inflating channels is selected in accordance with the width of the web of foils, the number of cushions in a group including interconnected cushions and the dimensions of the cushions considered. The thermoplastic foils utilized for manufacturing web of foils of the invention are made of any of the materials commonly utilized in the industry for manufacturing inflatable cushions. The fluids utilized for inflating the cushions according to the present invention can be various gases, liquids or gel such as commonly utilized in the industry.