Abstract:
A machine which inflates and seals pillows in packaging is compact in overall size, can be conveniently operated to produce varied lengths of strips of inflated pillow-type packaging as needed, can begin production of inflated pillow-type strip packaging immediately after being held out of a production cycle for some period of time, and applies a heated sealing element directly to and in sliding contact with a web of film to securely seal the inlet port of an inflated pillow while the pillow is under pressure and as the web of film is continuously and uninterruptedly advanced through the machine.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of application Ser. No. 11/186,820, filed Jul. 22, 2005, now U.S. Pat. No. 7,536,837, which is a continuation of application Ser. No. 10/732,437, filed Dec. 9, 2003, now U.S. Pat. No. 7,059,097, which is a division of application Ser. No. 10/366,812, filed Feb. 13, 2003, now U.S. Pat. No. 7,090,912, which in turn is a division of application Ser. No. 10/108,823, filed Mar. 26, 2002, now U.S. Pat. No. 6,605,169, and a division of application Ser. No. 09/638,843, filed Aug. 14, 2000, now U.S. Pat. No. 6,659,150, which in turn is a continuation-in-part of application Ser. No. 09/439,552, filed Nov. 12, 1999, now U.S. Pat. No. 6,209,286, which claims priority under 35 U.S.C. § 119(e) to Provisional Application No. 60/123,497, filed Mar. 9, 1999. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to methods and apparatus for inflating and sealing pillows in packaging. 
         [0003]    This invention relates particularly to the construction and operation of a machine which is small enough to be installed for operation on site where articles packaged for transport are placed in shipping containers with protective inflated pillow-type strip packaging. 
         [0004]    This invention relates particularly to a machine which is compact in overall size, which can be conveniently operated to produce varied lengths of strips of inflated pillow-type packaging as needed, which can begin production of inflated pillow-type strip packaging immediately after being held out of a production cycle for some period of time and which applies a heated sealing element directly to and in sliding contact with a web of film to securely seal the inlet port of an inflated pillow while the pillow is under pressure and as the web of film is continuously and uninterruptedly advanced through the machine. 
         [0005]    This invention relates particularly to a machine which forms the seal complete and secure during a short path of travel and during a short interval of time. The seal is made without the need for additional pressing together of the film after the sealing and without the need for additional cooling of the seal after the sealed inlet port moves out of contact with the sealing structure. 
         [0006]    Webs of plastic film which are constructed to permit the production of strips of air filled envelopes, cushions and pillows have (in the past ten years or so) been used extensively for cushioning objects to be transported in containers. 
         [0007]    The thin webs of plastic film are inexpensive, tough, resilient and recyclable. Strips of inflated pillow packaging which are created from these webs of plastic film are used for void-fill packaging to replace products such as crumpled paper or polystyrene peanuts and for protective packaging to replace molded or extruded foams. 
         [0008]    U.S. Pat. No. 5,454,642; U.S. Pat. No. 5,651,237; U.S. Pat. No. 5,755,328; U.S. Pat. No. 4,017,351; and U.S. Pat. No. 5,824,392 disclose methods, apparatus, and webs of plastic film used for making strips of inflated pillow packaging of this general kind. Each of these U.S. patents is incorporated by reference in this application. 
         [0009]    U.S. Pat. Nos. 6,116,600 and 6,209,286 also disclose methods, apparatus and webs of plastic film of this general kind and are incorporated herein by reference. 
         [0010]    Sealing an inflated pillow made a web of plastic film while the air inflates the pillow under pressure and while the web of plastic film is being transported through the machine presents problems. 
         [0011]    The seal must be secure and must not leak in order for the inflated pillow packaging to be used effectively for cushioning objects transported within a container. 
         [0012]    The seal needs to be formed efficiently, quickly and without extensive, related pressing and/or cooling structure in order to make the machine as compact as possible in size and as efficient as possible in production rate. 
         [0013]    To simplify machine construction and to provide a high efficiency of production, it is desirable to be able to make the seal as the web of plastic film is moved continuously and without any interruption and/or intermittent stopping of the film transport during the sealing operation. 
         [0014]    It is a primary object of the present invention to construct and to operate a machine which is compact in size, which is efficient in production, which is continuous and uninterrupted in operation and which produces seals which are secure and which do not leak. 
       SUMMARY OF THE PRESENT INVENTION 
       [0015]    In a specific embodiment of the present invention, a machine inflates and seals pillows in packaging while continuously and uninterruptedly advancing a web of film through an inflating station and a sealing station. The inflating station sequentially inflates pillows at preformed patterns in the web of film by introducing pressurized air through a narrow width inlet port of a preformed pattern. The sealing station seals each inlet port by applying a heated sealing element directly to and in sliding contact with the web of film while the air in an inflated pillow is under pressure as the inlet port moves across the heated sealing element. 
         [0016]    The web of film has an uninflated pillow pattern and an uninflated inflation channel preformed in the film. The uninflated pillow patterns comprise multiple, spaced apart, pillow patterns aligned along one side of an inflation channel. The inflation channel extends longitudinally and continuously along the entire length of the film. Each uninflated pillow pattern has a narrow width inlet port extending generally transversely to the longitudinally extending inflation channel and connecting the uninflated pillow pattern to the uninflated inflation channel so that, when pressurized air is introduced into the inflation channel, the pressurized air can be transmitted through the inlet port to inflate the pillow pattern. In some cases the preformed pattern is also formed with outlet ports connected to the inflation channel in such a way that air entering the inflation channel can move into a pillow through an inlet port and can also exit out of the inflation channel through the outlet port. The outlet port is generally shaped smaller than the inlet port. 
         [0017]    By allowing the air above a desired pressure to escape through an outlet port or ports, the pressure in the inflation channel is maintained at a desired level for inflating the pillows creating over-pressurization. 
         [0018]    The air escaping through the outlet port is also sensed to detect where the pillows are in the machine. These detected outlet port positions are then used as signals for an associated electronic unit to count the number of pillows inflated in a particular run through the machine. This also facilitates being able to stop the movement of the film through the machine after one production run of a selected number of inflated pillows at a position which is the right position to start a subsequent production run of a selected number of inflated pillows. 
         [0019]    In a specific embodiment of the present invention, the web of film with the preformed patterns is stored on a storage roller of the machine and is advanced through the machine by a first set of nip rollers and a second set of nip rollers at a respective first film transport station and a second film transport station. 
         [0020]    Pressurized air is introduced into the inflation channel of the web of film at an inflating station as the web of film is transported through the first film transport station. The pressurized air inflates at least one of the pillow patterns prior to the time the web of film is continuously transported through a sealing station. 
         [0021]    Pressure is maintained in the inflated pillow pattern within a calibrated pressure range during the time that the web of film is continuously transported through the sealing station. 
         [0022]    At the sealing station the inlet port of an inflated pillow is sealed by applying a heated sealing element directly to and in sliding contact with the web of film. The heated sealing element slides across the inlet port while the air in the inflated pillow is under pressure and as the web of film is continuously and uninterruptedly advanced throughout all components of the machine. 
         [0023]    The heated sealing element has a relatively small longitudinal dimension in the direction of movement of the web of film. In a specific embodiment the length of the heated sealing element is about the same as the width of the inlet port of a pillow pattern. This small size of the heated sealing element helps minimize the amount of sealing heat applied to the web of film. 
         [0024]    The sealing station includes a sealing roller disposed alongside the heated sealing element so as to permit the web of film to be advanced between the sealing roller and the heated sealing element. Adjustable biasing means provide for adjustment of the force with which the heated sealing element and the sealing roller are pressed toward engagement with one another. 
         [0025]    The sealing roller is positioned with respect to the first and second pairs of nip rollers so as to cause the web of film to wrap around a part of the peripheral surface of the sealing roller both in a circumferential direction and also in a lateral direction. This helps create a dead and flat zone right at and adjacent to the line of sealing across the inlet port. This in turn facilitates making a secure seal without leaking while the pillow is inflated under pressure. 
         [0026]    The axes of rotation of at least the second pair of nip rollers are preferably canted at a slight angle with respect to the axis of rotation of the sealing roller. 
         [0027]    The second pair of nip rollers are preferably rotated at a speed slightly faster than the speed of rotation of the first pair of nip rollers so as to maintain tension in the web of film between the second and first pair of nip rollers. 
         [0028]    In one specific embodiment of the present invention the heated sealing element is a fabric covered Nichrome wire disposed at the end of a bar element which is biased toward engagement with a sealing roller. The fabric covering of the Nichrome wire has a Teflon coating on its outer surface for facilitating sliding of the heated sealing element on the engaged surface of the film as the web of film is advanced through the machine. 
         [0029]    The bar on which the heated sealing element is mounted is a composite bar. The very tip of the bar is a ceramic having good insulating qualities, and the remainder of the bar is a different material selected to provide enhanced mechanical durability. 
         [0030]    The seal is formed complete and secure during a short path of travel through the sealing station. 
         [0031]    The seal is complete and secure at the time the web of film moves out of contact with the wheel at the sealing station and without the need for additional pressing together of the film after the sealing station and without the need for additional cooling of the film across the sealed inlet port after the sealed inlet port moves out of contact with the sealing station. 
         [0032]    In a second specific embodiment of the present invention the sealing wheel is pressure biased toward engagement with the heated sealing element. 
         [0033]    In both the first and second specific embodiments the heated sealing element and the sealing wheel are spaced apart from one another when the machine is not transporting the web of film through the machine in a production run. This enables the heated sealing element to be maintained at a desired temperature level while preventing contact with and possible burning of the unmoving film at the sealing station. 
         [0034]    In one specific embodiment of the invention the fabric covering for the Nichrome wire is held in a fixed position at the end of the bar element and is replaced as needed. 
         [0035]    In another specific embodiment of the invention the heating station includes a cartridge unit which can be quickly and easily interchanged with another cartridge unit. The cartridge unit includes an elongated strip of the fabric covering. The strip is mounted on two rotatable reels. The fabric always covers the Nichrome wire, as in the first specific embodiment, and the fabric has a Teflon coating on the side which engages the film in sliding contact, as in the first specific embodiment. The elongated strip of fabric covering is wound between the two reels so as to be moved across the length of the Nichrome wire at a speed which is much slower than the speed of movement of the film through the machine but which is fast enough to ensure that the covering strip of fabric is always effective to function properly without any burn through of the fabric or damage to the film from the heated Nichrome wire. The cartridge unit permits the Nichrome wire of the heated sealing element to be easily disconnected from its power supply. The cartridge units are constructed to be readily interchanged as units, rather than having to replace individual components of the cartridge unit. 
         [0036]    Methods and apparatus which incorporate the features noted above and which are effective to function as described above comprise further, specific objects of this invention. 
         [0037]    Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings, which by way of illustration, show preferred embodiments of the present invention and the principles thereof and what are now considered to be the best modes contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING VIEWS 
         [0038]      FIG. 1  is an isometric view of a machine, constructed in accordance with one embodiment of the present invention, for inflating and sealing pillows in packaging.  FIG. 1  is a general view which illustrates how a web of film is transported through the machine.  FIG. 1  shows how the web of film has a preferred pattern of spaced-apart, inflatable pillows aligned along one side of a longitudinally extending inflation channel.  FIG. 1  illustrates how rollers (at a first transport station, at a sealing station, and at a second transport station) are positioned to engage the underside (as viewed in  FIG. 1 ) of the web of film. 
           [0039]      FIG. 2  is another isometric view of the machine shown in  FIG. 1 , but in  FIG. 2  the lower part of the figure has been revised to (in effect) see through the web of film in order to show details of certain structure of the machine.  FIG. 2  shows the inflation tube of the inflating action, the nip rollers of the first transport station, the heated sealing element and the associated sealing roller at the sealing station, and the nip rollers at the second transport station. 
           [0040]      FIG. 3  is an isometric view of the machine of  FIGS. 1 and 2 , but without the web of film material.  FIG. 3  shows the main structural and operative features of the machine itself. 
           [0041]      FIG. 4  is an isometric, enlarged view showing details of the features of the first film transport station, the inflation station structure, the sealing station structure, the slitting station structure, and the second film transport station structure. 
           [0042]      FIG. 5  is an isometric, enlarged view like  FIG. 4  but shows details of just the mechanism for driving the various rollers of the machine.  FIG. 5  does not show the inflation station structure, the heated sealing element at the sealing station, or the slitter structure for opening up the inflation tube of the web of film after the sealing station. 
           [0043]      FIG. 6  is an isometric view showing details of the structure of the sealing station.  FIG. 6  shows the heated sealing element pressed toward engagement with the sealing wheel in the positions occupied by those two components during a production run of the inflated pillow packaging through the machine. 
           [0044]      FIG. 7  is a top plan view, taken along the line and in the direction indicated by the arrows  7 - 7  in  FIG. 6 , but showing the heated sealing element retracted away from the sealing wheel in the positions occupied by those two components when no film is being transported through the machine. 
           [0045]      FIG. 8  is a top plan view of a specific embodiment of a web of film constructed in accordance with the present invention and having a specific pattern of inflatable pillows, inlet ports for permitting inflation of the pillows, and escape ports for preventing over pressurization of the pillows and for also permitting more accurate position sensing of the pillows as the web of film moves through the machine. 
           [0046]      FIGS. 9A-9G  are a series of the isometric views showing details of the structure, components and sequence of assembly of certain components of the heated sealing element at the sealing station. 
           [0047]      FIG. 10  is an isometric view of a machine constructed in accordance with a second embodiment of the present invention. The embodiment of the machine shown in  FIG. 10  includes a cartridge unit which is mounted on a separate sub-plate or sub-frame and which permits all of the components of the cartridge unit to be quickly and easily removed and replaced by another, replacement cartridge unit. The cartridge unit provides the heated sealing element components for the sealing station.  FIG. 10  shows the sealing wheel of the sealing station positioned to engage the web of film in sliding contact with the heated sealing element during a production run of packaging. 
           [0048]      FIG. 11  is an isometric view like  FIG. 10  but showing the sealing wheel moved to a retracted position which permits the web of film to move out of contact with the heated sealing element when the machine is stopped between production runs and the film is not being transported through the machine. 
           [0049]      FIG. 12  is an enlarged, isometric view of the replaceable cartridge unit itself.  FIG. 12  shows the strip of covering fabric in stored positions on the reels of the cartridge unit prior to installation of the cartridge unit in the machine. When installed in the machine, a portion of the strip of covering fabric is positioned over the wire of the heating element (as illustrated in  FIGS. 10 and 11 ). 
           [0050]      FIG. 13  is an enlarged, isometric view of the sealing wheel and the related actuator mechanism for positioning the sealing wheel at the sealing station. 
           [0051]      FIG. 14  is an enlarged, side elevation view of the sealing station structure with the structure in the operative position shown in  FIG. 10 ; and, 
           [0052]      FIG. 15  is an enlarged, side elevation view of the sealing station structure with the structure in the non-operating position shown in  FIG. 11 . 
           [0053]      FIG. 16  is an isometric view of a machine for manufacturing air-filled sheet plastic shipping pillows or cushions in a continuous manner from a roll of film material in accordance with another embodiment of the present invention. 
           [0054]      FIG. 17  shows an alternative embodiment of the machine shown in  FIG. 16 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0055]      FIGS. 1 ,  2  and  3  are isometric views of a machine, constructed in accordance with one embodiment of the present invention, for inflating and sealing pillows in packaging. 
         [0056]    The machine is indicated by the general reference numeral  11  in each of  FIGS. 1 ,  2  and  3 . 
         [0057]    The machine  11 , as most easily viewed in  FIG. 3 , comprises a main plate  13  on which various structural and operational features are mounted. 
         [0058]    A support tube  15  is mounted at the upper (as viewed in  FIGS. 1-3 ) of the main plate  13  for supporting a roll  17  of a web of film  19  (see  FIGS. 1 and 2 ). 
         [0059]    Guide tubes  21  and  23  are mounted on the plate  13  below the tube  15 . The tubes  21  and  23  serve to guide the web of film  19  from the roll  17  to the operating mechanism  25  of the machine  11 . The operating mechanism  25  is described in more detail below. 
         [0060]    The mechanism  25  is illustrated in detail in  FIG. 4  and comprises a first film transport station  27 , a second film transport station  29 , an inflating station  31 , a sealing station  33 , and a slitting station  35 . 
         [0061]    The first film transport station  27  includes a first pair of nip rollers  37  and  39  for gripping the web of film  19  (see  FIG. 1 ) and for pulling the web of film  19  from the roll  17  and under and over the guide tubes  21  and  23  and through the first film transport station  27  when the nip rollers are rotated by associated drive gears  41 ,  43  and a drive belt  45 . The nip rollers  37  and  39  are rotated in the directions indicated by the direction arrows on the drive gears  41  and  43  shown in  FIG. 4 . 
         [0062]    The drive belt  45  is driven by a drive gear  47  which is in turn driven by a motor  49  (see  FIG. 5 ). 
         [0063]    The second film transport station  29  comprises a second pair of nip rollers  49  and  51  which grip the web of film  19  to continuously advance the web of film  19  from the first transport station  27  to and through the inflating station  25  and to and through the sealing station  33  and then to and through the second film transport station  29 . 
         [0064]    The nip rollers  49  and  51  are driven by drive gears  53  and  55  and in the rotational directions indicated by the directional arrows on the drive gears  53  and  55  in  FIG. 4 . 
         [0065]    Drive shafts  40  and  44  transmit the drive from the drive gears  41  and  43  to the nip rollers  37  and  39 . 
         [0066]    Drive shafts  50  and  52  transmit the drive from the drive gears  53  and  55  to the nip rollers  49  and  51 . 
         [0067]    With continued reference to  FIG. 4 , the drive belt  45  passes about an idler gear  57 . The drive gears  41 ,  43 ,  47 ,  53 ,  55  and idler gear  57  are all mounted for rotation on and are supported by the main plate  13 . 
         [0068]    The inflating station  31  includes an inflation tube  59  and a generally spherically shaped and partially Teflon coated ball  61  located at the upper end (as viewed in  FIG. 4 ) of the tube  59 . The ball  61  has a plurality of openings  63  for injecting pressurized air into an inflation channel in the web of film  19 . 
         [0069]    As illustrated in  FIGS. 1 ,  2  and  8 , the web of film  19  as stored on the roll  17  shown in  FIG. 1  has a pattern of pillows  65 , a longitudinally extending inflation channel  67 , inlet ports  69 , and outlet ports  71  preformed in the web of film. The pillows  65 , channel  67 , ports  69  and ports  71  are uninflated in the web of film as stored on the roll  17 . 
         [0070]    The uninflated pillow patterns  65  are longitudinally spaced apart from one another and are aligned (in the embodiment of the web of film  19  illustrated in the drawings) along one side of the inflation channel  67 . 
         [0071]    The inflation channel  67  extends longitudinally and continuously along the entire length of the web of film  19 . 
         [0072]    The inflation channel  67  is dimensioned to provide a close, sliding fit over the Teflon coated ball  61 . 
         [0073]    Each pillow  65  is connected to the inflation channel  67  by an inlet port  69 . The inlet port  69  extends generally transversely to the longitudinally extending inflation channel  67  and has a narrow interior width which is positioned at the sealing station  33  (in a manner to be described more fully below) to facilitate quick and secure sealing of pressurized air within an inflated pillow  65  in a small path of travel and in a short time of continuous, uninterrupted travel through the sealing station  33 . 
         [0074]    The outlet ports  71  are shaped to be somewhat smaller than the inlet ports  69 . These outlet ports  51  are located on the side of the channel  67  opposite the inlet ports  69  and are generally aligned with the inlet ports  69 . 
         [0075]    As will be described in greater detail below, the outlet ports  71  allow air to escape in a way to maintain pressure in the channel  67  and in the inflated pillows at a calibrated, desired level without creating over-pressurization in the pillows. 
         [0076]    In addition, the air that exists from an outlet port  71  can be sensed by a pressure transducer  73  (see  FIG. 8 ) to allow for accurate position sensing of the pillows as the pillows move through the machine  11 . 
         [0077]    The air escaping through the outlet ports is sensed to detect where the pillows are in the machine. These detected outlet port positions are then used as signals for an associated electronic unit to count the number of pillows inflated in a particular run through the machine. This also facilitates being able to stop the movement of the film through the machine, after one production run of a selected number of inflated pillows, at a position which is the right position to start a subsequent production run of a selected number of inflated pillows. 
         [0078]    The upper end of the inflation tube  59  is formed with a small curvature so as to better follow the path of the film  19  as the film is advanced through the first transport station  27  and the sealing station  33 . 
         [0079]    Details of the construction and mode of operation of the sealing station  33  are illustrated and will be described with reference to  FIGS. 4 ,  6  and  7 . 
         [0080]    The sealing station  33  comprises a sealing roller  75  mounted on a shaft  77  which is in turn mounted for rotation in a bearing assembly attached to the main plate  13 . 
         [0081]    The sealing station  33  also comprises a heated sealing element located at the outer end (the right hand end as viewed in  FIG. 7 ) of a bar  81 . The very tip  80  of the bar  81  is a ceramic of aluminum silicate to provide an insulation function, and the remainder of the bar  81  is a different material selected for mechanical durability. 
         [0082]    The bar  81  is mounted for sliding motion within a support  83 . 
         [0083]    A spring  85  and an adjustment screw  87  provide a selectable bias force for biasing the bar  81  toward the opposed periphery of the roller  75  so that the film  19  (in the longitudinally extending strip which crosses the inlet ports  69 ) is pressed in rolling contact with the outer periphery roller  75  and in sliding contact with the end surface of the bar  81  as the first and second film transport stations continuously advance the web of film  19  through the sealing station  33 . 
         [0084]    An actuator  89  is included in the sealing station  33  for retracting the bar  81  against the bias of spring  85  and away from engagement with the roller  75  when the film  19  is not being advanced through the machine  11 . This facilitates keeping the heating element energized at the proper heating level and out of contact with the film  19  during time intervals when the machine  11  is not being used to produce inflated pillow packaging. 
         [0085]    Details of the structure, components and sequence of assembly of components of the heated sealing element are shown in the exploded views of  FIGS. 9A-9F . 
         [0086]    The heating element disposed at the end of the bar  81 , in a specific embodiment of the present invention, comprises at least one Nichrome wire  70  which runs vertically (as viewed in  FIGS. 9A-9G ) along the right hand end of the bar  81 . 
         [0087]    The Nichrome wire  70  at this location has a length about the same as the throat width of an outlet port  69  in the film  19 , and the Nichrome wire  70  is covered by a fabric  72  having a Teflon coating on the surface which contacts the film  19 . The fabric covering  72  helps to form the wire  70  to a preferred shape for engagement with the film  19 , and the Teflon coating facilitates sliding movement of the film  19  with respect to the heated sealing element. 
         [0088]    The heated sealing element comprises at least one Nichrome wire  70 , but (as illustrated in  FIGS. 9A-9F ) the present invention also encompasses using a plurality of parallel extending and laterally spaced apart Nichrome wires  70  for providing multiple seal lines across inlet ports  69  of the pillows  65 . 
         [0089]    As best illustrated in  FIGS. 6 and 7 , wires  91  and  93  conduct electricity to the Nichrome wire for heating the Nichrome wire. 
         [0090]    The slitting station  35  (see  FIG. 4 ) includes a blade  95  attached to the inflation tube  59  and positioned to slit the inflation channel  67  in the film  19  after the outlet port  69  of a pillow  65  has been sealed at the sealing station  33 . This enables strips of inflated packaging to be removed from the machine  11 . 
         [0091]    It is an important feature and benefit of the present invention that the components of the mechanism  25  and the coaction between those components enable a seal to be formed complete and secure in a short path of travel of the film through the sealing station  33  and in a short period of time and without the need for additional pressing together of the web of film after the sealing station and without the need for additional cooling of the seal across the inlet port after the sealed inlet port moves out of contact with the sealing station. The sealing of the inlet port at the sealing station is performed by applying the heated sealing element directly to and in sliding contact with the web of film and across the inlet port while the air and the inflated pillow is under pressure and as the web of film is continuously and uninterruptedly advanced through the mechanism  25  shown in  FIG. 4 . 
         [0092]    A number of features of the present invention contribute to obtaining this efficient and beneficial sealing result. 
         [0093]    As described above, the outermost tip of the bar  81  is a ceramic material which functions as an insulator to help confine the heat of the heating element to substantially just the linear area of contact of the fabric covered Nichrome wire with the film  19 . 
         [0094]    The roller  75  is laterally offset outwardly (as viewed in  FIGS. 1-5 ) and is positioned with respect to the pairs of nip rollers  37 - 39  and  49 - 51  so as to cause a bump in the film  19  at the sealing station  33 . This helps to create a dead zone adjacent the inlet port  69  to be sealed by causing the web of film  19  to wrap around a part of the peripheral surface of the sealing roller  75  both in a circumferential direction and also in a lateral direction. 
         [0095]    Driving the second pair of nip rollers  49 - 51  at a slightly higher speed than the first pair of nip rollers  37 - 39  helps to insure that the film  19  is maintained flat and in substantially pressure sealing engagement with the periphery of the sealing roller  75 . 
         [0096]    As best shown in  FIG. 5 , the axes of rotation of at least the second set of nip rollers  49 - 51  are preferably canted at a slight upward (as viewed in  FIG. 5 ) angle with respect to the axes of rotation of the main drive gear  47  and the sealing roller  75 . 
         [0097]    In a specific embodiment of the present invention the axes of rotation of the first set of nip rollers  37 - 39  are also canted at this same slightly upwardly inclined angle. 
         [0098]    The inclusion and positioning of the outlet ports  71  (see  FIG. 8 ) and the smaller size of these outlet ports contribute to allowing air to escape through the outlet ports in an amount to maintain sufficient pressure in the channel  67  without permitting over-pressurization in that channel  67  or in the pillows  65 . 
         [0099]    The present invention permits sealing the inlet port at a sealing station by applying a heated sealing element directly to and in sliding contact with the web of film and across the inlet port while the air and the inflated pillow is under pressure and as the web of film is continuously and uninterruptedly advanced through each of the first transport station, inflating station, sealing station, second transport station and slitting station. 
         [0100]    In  FIGS. 1 ,  2  and  8  of the drawings the pillows  65  are shown in a generally rectangular-shaped pattern. It should be noted, however, that the pillows  65  can be any preformed pattern configuration. The patterns of the pillows  65  can, for example, include preformed seal line elements within the interior of the pillows which permit the pillows to be folded along one or more of the preformed interior seal lines. This in turn permits one pillow to cushion an object in more than one direction when placed within a shipping container. 
         [0101]    Score lines (not illustrated in the drawings, but similar to score lines shown in webs of plastic film described in numerous ones of the prior U.S. patents incorporated by reference in this application) permit ready detachment of single ones or groups of inflated pillows from the film  19  after the pillows are inflated and sealed. 
         [0102]    A number of different film compositions (also as noted in U.S. patents incorporated by reference in this application) can be used as the composition material for the web of film  19 . 
         [0103]    The machines that are used to preform the patterns on the web of film  19  include conventional presses which impress multiple pillow patterns (and the related ports and inflation channel) on a strip of film  19  on each pressing operation. The pattern is formed while there is no inflation pressure anywhere in the web  19 . 
         [0104]    The preformed pattern can also be formed by a roller arrangement in which at least one roller is heated and configured to form the desired patterns. 
         [0105]    Pattern forming machines of these kinds are also disclosed in several of the U.S. patents incorporated by reference in this application. 
         [0106]    Such machines for forming preformed patterns in the film  19  can be associated with the machine  11  shown in  FIG. 1  to replace the storage roll  17  so that the preformed patterns can be preformed continuously at the site where the machine  11  is installed. However, in most cases it is more practical to use a storage roll  17  with preformed patterns than it is to preform the patterns at the job site where the machine  11  is to be used. 
         [0107]    A second embodiment of a machine constructed in accordance with the present invention is illustrated in  FIGS. 10-15  of the drawings. This second embodiment is indicated by the general reference numeral  101 . 
         [0108]    The components and parts of the machine  101  which correspond to the machine  11  shown in  FIGS. 1-9  are indicated by corresponding reference numerals. 
         [0109]    The machine  101  includes a cartridge unit  103  (see  FIG. 12 ) which is mounted on a separate sub-plate or sub-frame  105 . The sub-frame  105  is mounted on the main plate or main frame  13 . This cartridge unit technique permits the components of the entire cartridge unit to be quickly and easily interchanged (as a unit) with another replacement cartridge unit. Individual components of the cartridge unit do not have to be removed and replaced. 
         [0110]    In the machine  101  shown in  FIGS. 10-15 , the construction and mounting of the cartridge unit  103  permits the entire cartridge unit to be pulled out of a box and plugged in as a unit at the production site. This cartridge unit permits all of the components of the cartridge unit to be replaced as a unit. It is never necessary, for example, to replace the Nichrome wires as individual elements in the field. Instead, the entire cartridge unit is just pulled out and replaced as a unit with a replacement cartridge unit. 
         [0111]    The structure, components and mode of operation of the first film transport station  27 , the second film transport station  29 , the inflation station  31 , and the slitting station  35  are the same as the corresponding mechanism, components and mode of operation described above with reference to the machine  11 , and will not be reviewed in more specific detail at this point. 
         [0112]    The specific structure of the sealing station  33  of the machine  101  is different from the machine  11  and will be described in more detail below. However, the method of making seals across the inlet ports  69  in the machine  101  is the same as the method of machine  11 , as will be understood from the description to follow. 
         [0113]    One difference between the sealing station structure of the machine  11  and the sealing station structure of the machine  101  is in the way that the heated sealing element and the sealing wheel are moved apart from one another during those times when the machine is stopped between production runs of inflated pillows. 
         [0114]    In the machine  11  (and as illustrated in  FIG. 7 ) the heated sealing element which is mounted on the end of the bar  81  is retracted away from the sealing wheel  75 . In the machine  11  the shaft  75  of the heated sealing wheel  75  is held in a fixed position with respect to the frame  13  in all modes of operation of the machine  11 . 
         [0115]    In the machine  101  the heated sealing element is held in a fixed position with respect to the frame  13 . The rotational shaft  77  of the sealing wheel  75  is mounted for rotation in a movable support bracket  75  so that the sealing wheel  75  is movable toward and away from the heated sealing element. 
         [0116]    As best illustrated in  FIG. 13 , the support bracket  75  is mounted on a rod  82  of an actuator  84 . The actuator  84  is mounted on a support plate  86 , and the support plate  86  is mounted on the main plate  13  of the machine  101 . 
         [0117]    The actuator  84  extends and retracts the rod  82  to move the sealing wheel  75  between the retracted position of the rod  82  shown in  FIGS. 11 and 15  and the extended position shown in  FIGS. 10 and 14 . 
         [0118]    In the retracted position illustrated in  FIGS. 11 and 15  the sealing wheel  75  is positioned to let the film  19  remain out of contact with the heated sealing element when the machine  101  is not operated in a production run. 
         [0119]    In the extended position shown in  FIGS. 10 and 14  the sealing wheel  75  is positioned to engage the film  19  and to press that film  19  in sliding contact with the heated sealing element as the film  19  is continuously and uninterruptedly advanced through the machine during a production run of inflated pillows. 
         [0120]    In the extended position shown in  FIGS. 10 and 14  the sealing wheel  75  is positioned to engage the film  19  and to press that film  19  in sliding contact with the heated sealing element as the film  19  is continuously and uninterruptedly advanced through the machine during a production run of inflated pillows. 
         [0121]    The force with which the film  19  is engaged in sliding contact with the heated sealing element is determined by selecting the pressure level within the actuator  84 . 
         [0122]    As best illustrated in  FIGS. 12 ,  10 , and  14 , the cartridge unit  103  comprises a guide block  107  mounted in a fixed position on the sub-plate  105 , two reels  109  and  111 , each mounted for rotation on the sub-plate  105 , and a guide post  113  mounted on the sub-plate  105 . 
         [0123]    The reels  109  and  111  are storage and take-up reels for a strip of covering fabric  72 . The fabric  72  has a Teflon coating on the side engaged in sliding contact with the film  19 . 
         [0124]    The strip of covering fabric  72  is trained around a guide post  113  and into the guide slots  115  and  117  which are recessed within the outer and forward surfaces of the flanges  119  and  121  of the guide block  107 . 
         [0125]    The way that the strip of covering fabric  72  is conveyed from the storage roller  109 , around the guide post  113 , through the guide slot  115 , over the Nichrome wires  70 , through the guide slot  117  and onto the reel  111  is best illustrated in  FIGS. 10 ,  11 ,  14  and  15 . 
         [0126]    In a specific embodiment of the machine  101  the lower reel  111  is driven, through reduction gearing, and by an electric motor (not shown), to pull the strip of covering fabric  72  across the Nichrome wires  70  at a relatively slow speed (a speed considerably slower than a speed at which the web of film  19  is transported through the machine  101  during a production run), but at a speed fast enough to insure that no part of the covering fabric  72  is ever in contact with the Nichrome wires  70  long enough to permit any burn through of the fabric by the Nichrome wires  70 . The reel storage of the covering fabric  72  and the slow movement of the fabric with respect to the Nichrome wires  70  during operation of the machine  101  thus insure that the area of the fabric engageable with the Nichrome wires is, in effect, renewed soon enough to prevent any burn through. 
         [0127]    As best illustrated in  FIGS. 12 and 15 , the outer tips of the flanges  119  and  120  extend slightly beyond the outer surfaces of the Nichrome wires  70 . This insures that the covering fabric  72  is engaged with the Nichrome wires  70  only when the sealing wheel  75  is moved to the position shown in  FIGS. 10 and 14  during a production run of the machine  101 . 
         [0128]    The strip of covering fabric  72  is held out of contact with the Nichrome wires  70  when the machine  101  is not being operated in a production run of packaging. 
         [0129]    While not illustrated in  FIGS. 10-15 , the Nichrome wires  70  are energized by detachable leads  91  and  93  (as illustrated for the machine  11  in  FIGS. 9A-9G ). 
         [0130]    The sealing roller  75  of the machine  101  is laterally offset outwardly in the same way as the sealing roller  75  of the machine  11  so as to cause a bump in the film  19  at the sealing station  33 . This helps to create a dead zone adjacent the inlet port  69  to be sealed by causing the web of film  19  to wrap around a part of the peripheral surface of the sealing roller  75  both in circumferential direction and also in a lateral direction (as described above with reference to the machine  11 ). 
         [0131]    The machine  101  permits sealing the inlet port at a sealing station by applying a heated sealing element directly to and in sliding contact with the web of film and across the inlet port while the air in an inflated pillow is under pressure and as the web of film is continuously and uninterruptedly advanced through each of the first transport station, inflating station, sealing station, second transport station and slitting station. 
         [0132]      FIG. 16  illustrates a machine  240  for manufacturing a continuous production of pneumatically filled packaging pillows in accordance with another embodiment of the present invention. The strip of flattened preformed film material  210  having continuous heat seals  214  defining pillow chambers  216  is compactly wound onto roll  220  and placed at one end of the machine  240 . The preformed film material  210  is advanced along a path through the machine  240  and is first fed between a set of tightly spaced nip rollers  242 . The opening to the common inflation channel  218  of the preformed sheet of material  210  is guided onto inflation tube  244  at a first station and is pulled further into the machine  240  by a first set of drive rollers  246 . The drive rollers  246 , in combination with the closely spaced pair of free spinning idler wheels or rollers  248 , provide a direct drive means for advancing the preformed sheet material  210  along the inflation tube  244  in the direction of travel indicated by arrow B and at a rate substantially equal to the rotational speed of the drive rollers  246 . 
         [0133]    A seal forming apparatus, generally indicated by reference arrow  252  in  FIG. 16 , is located downstream of the first set of drive rollers  246  and defines a second station of the machine  240 . The seal forming apparatus  252 , through a combination of light pressure and heat, is effective to form a pair of spaced apart and continuous seals, each seal being formed along opposite sides of the inflation channel  218 . The continuous seals formed by the seal forming apparatus are effective to seal off the entrance ports  220  and thereby trap a quantity of pressurized air within each pillow chamber  216 . 
         [0134]    Located downstream of the seal forming apparatus  252  is what is referred to as the take up section  253 . In the embodiment of  FIG. 16 , take up section  253  comprises the combination of a second set of drive rollers  254  and a belt drive assembly  256 . The take up section  253  is effective to (1) take up the slack in the preformed film material  210  by keeping the film material  210  taut in the lengthwise or longitudinal direction and (2) pull the film material  210  through the seal forming apparatus  252 . The belt drive assembly  256  includes an elastomeric belt  258 , preferably of silicone rubber, which loops around forward wheel  260  and rearward wheel  262 . In the embodiment described herein, only the rearward wheel  262  is driven, the forward wheel being free spinning. The second set of drive rollers  254  are driven at a higher rate of speed than the first set of drive rollers  246 . The rearward wheel  262  of the belt drive assembly is preferably driven at an even higher rate of speed than the second set of drive rollers  254 . The contact pressure between the film material  210  and the combination of second set of drive rollers  254  and belt drive assembly is light, however, such that there is sufficient drag force on the film material  210  to continue advancing it through the machine  240  but not so great a drag force that would otherwise cause the film material  210  to separate along the perforations or score lines  221 . The combination of drive rollers  254  and belt drive assembly  256  effectively form a clutch with both the drive rollers  254  and belt  258  slipping against the film material  210 , but at different speeds. 
         [0135]    The inflation tube  244  is further provided with a blade  278  at a third station downstream of the seal forming apparatus  252 . The blade  278  is generally angled and is operative to cut either one of the upper, lower or both layers of the preformed film material  210  in the region of the common inflation channel  218 , thus allowing the common inflation channel  218  to separate from the tube  244  so that the strip of adjacent and connected (and now) inflated pillow sections are able to continue to progress forward through the machine  240 . The blade  278  is positioned upstream of the contact point between the second set of drive rollers  254  and belt  258  such that any friction imparted by the blade onto the film material  210  is compensated for by the drag force imparted on the preformed film material  210  by the drive rollers  254  and belt  258 . 
         [0136]    As an option, the machine  240  may further include another take up roller  264  positioned downstream of the belt drive assembly  256  (see  FIG. 16 ). The take up roller  264  is driven at a high rate of speed in order to take up the slack in the film material  210  after passing through the second set of drive rollers  254  and belt drive assembly  256 . Upon exiting the second set of drive rollers  254  and belt drive assembly  256 , the now air-filled and sealed pillow sections can then be separated from each other along the perforations  221  using a cutter  266  as shown to produce individual air-filled pillows or cushions. Alternatively, the air-filled pillow sections can be kept together as a continuous sheet which can be broken apart into pillows as desired by the end user. 
         [0137]      FIG. 17  illustrates a machine  440  for producing air-filled packaging pillows in a continuous manner from a roll  228  of preformed film material in accordance with an alternate embodiment of the invention. The machine  440  of  FIG. 17  is substantially identical to the machine  240  of  FIG. 16  with the exception of the take up section. In all other respects, structural elements of the machine  440  of  FIG. 17  common to machine  240  of  FIG. 16  are indicated by identical reference numerals. In machine  440 , take up section  453  includes a pair of opposing rollers or wheels  454  and  456 . Rollers  454  are free spinning and are used to heat seal the film material at the port openings of each pillow chamber. The rollers  454  are made of a heat conducting material, preferably aluminum, and are heated to a constant temperature or optionally fitted with electrically regulated nichrome heating elements. The rollers  456  are driven and are positioned in light contact with rollers  454  in order to both advance the film material  10  through the machine  440  and drive the free spinning rollers  454 . 
         [0138]    While we have illustrated and described the preferred embodiments of our invention, it is to be understood that these are capable of variation and modification, and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.