Abstract:
An airbag folding apparatus includes a folding tube, a folder support apparatus, and a plunger mechanism. The folding of an airbag utilizing the folding apparatus comprises the following steps. A vehicle airbag is attached to the plunger mechanism and the airbag is lowered into the folding tube. The plunger mechanism is introduced into the folding tube after the airbag is completely inside the folding tube. The plunger mechanism is forcibly lowered into the folding tube causing the airbag to be compressed or folded. The plunger mechanism remains exterior to the airbag throughout the folding process. The plunger mechanism is then detached and a fold retention sheet is wrapped around the folded airbag.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 60/257,474 entitled, “Passenger side air bag folding apparatus and method of folding,” filed on Dec. 21, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a method and an apparatus for folding an airbag.  
         BACKGROUND AND SUMMARY OF THE INVENTION  
         [0003]    Vehicle airbags are found in most automobiles and in the event of a collision, they are inflated by gas originating from an inflator. The vehicle airbags together with the inflators are mounted in a vehicle as part of the airbag module. The airbags are usually arranged in the airbag module in a folded state and must be folded in such a way that it can unfold as quickly as possible in a specific direction.  
           [0004]    Airbags are conventionally folded by spreading the airbag cushion out flat and then folding it specifically at predetermined points resulting in a folded arrangement. This folded arrangement can be accomplished manually, by an automated machine, or both.  
           [0005]    There are several disadvantages to the conventional folding method. For example, a very large amount of space is necessary for the purpose of folding the airbag, since the entire airbag must first be spread out flat. Also, the folding process is time consuming since the airbag has to be precisely folded. Furthermore, for automated folding of the airbag, there is a need for a relatively complicated installation, which has to be adapted individually to each case to different airbag shapes and the specific folding sequence thereof. Such complicated folding can only be performed at a limited speed.  
           [0006]    U.S. Pat. No. 6,248,052 B1 teaches a method for the folding of an inflatable airbag for motor vehicles which comprises the steps in which an airbag to be folded is fastened with its open end at a carrier. A piston is pushed forward into the airbag through an opening in the carrier and against the closed end of the airbag. The carrier and the piston are introduced into a sleeve, with the airbag being pressed together irregularly.  
           [0007]    U.S. application Ser. No. 09/390,428 teaches a method for folding an airbag for an airbag module involving the straightening out of the airbag, pushing or drawing the airbag into an outer guide device, and lastly pushing the airbag together with the outer device to fold the airbag.  
           [0008]    In the present invention, the folding apparatus comprises a plunger mechanism, a folder support apparatus, and a folding tube. The plunger mechanism has a plunger plate, which is attached to an airbag during the folding process. The folder support apparatus has a base reservoir for accommodating the airbag in its folded state. The folding tube has an upper rim defining an opening for receiving an airbag.  
           [0009]    The process of folding the airbag consists of the following steps. Attaching a plunger mechanism to an airbag and dropping the airbag into a folding tube. The airbag is compressed into a folder base of the folding tube by forcibly lowering the plunger mechanism down the folding tube, wherein the plunger mechanism remains exterior to the airbag during the folding process. Lastly, the folded airbag is wrapped with a fold retention sheet to prevent it from becoming unfolded. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The invention is explained in more detail with reference to the figures, in which:  
         [0011]    [0011]FIG. 1 shows a perspective view of an airbag folding apparatus.  
         [0012]    [0012]FIG. 2 shows the folding tube being raised in direction A.  
         [0013]    [0013]FIG. 3 shows the folding tube in an uppermost position.  
         [0014]    [0014]FIG. 4 shows a folder support apparatus with a fold retention sheet.  
         [0015]    [0015]FIG. 5 shows the folder tube being lowered in direction B.  
         [0016]    [0016]FIG. 6 is a perspective view of the folding apparatus with an airbag.  
         [0017]    [0017]FIG. 7 shows an airbag being compressed by a plunger mechanism.  
         [0018]    [0018]FIG. 8 shows an airbag fully compressed in the folding apparatus.  
         [0019]    [0019]FIG. 9 shows a folding apparatus with the folding tube in the raised position.  
         [0020]    [0020]FIG. 10 shows a folded airbag wrapped with a fold retention sheet in the folder base.  
         [0021]    [0021]FIG. 11 shows a perspective view of a cushion pack.  
         [0022]    [0022]FIG. 12 shows a bottom view of a cushion pack.  
         [0023]    [0023]FIG. 13 shows a second embodiment of a folding apparatus with a stationary folding tube. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    In accordance with the present invention, a folding apparatus  9  is utilized to compress or fold an airbag  41  so that it fits inside an airbag module. FIG. 1 shows a folding apparatus  9  comprising a plunger mechanism  38 , a folding tube  10 , and a folder support apparatus  17 .  
         [0025]    The plunger mechanism  38  includes a push tube or rod  40  and plunger plate  39 . The plunger mechanism  38  is utilized to compress the airbag  41  inside the folding tube  10 . The plunger plate  39  of the plunger mechanism  38  is attached to the airbag  41  during the folding process, which will be subsequently discussed.  
         [0026]    The folding tube  10  in FIG. 1 is shown in its bottommost position, with the lower rim  11  of the folding tube  10  flush against the folder base  17  of a folder support apparatus  15 . It is not necessary for all four sides of the folding tube  10  to be transparent and as such only the front face can be transparent. The folding tube  10  has an upper rim  12  defining a first opening for receiving an airbag  41  and the plunger mechanism  38 .  
         [0027]    The folder support apparatus  15  includes a top support member  16  defining a second opening as well as the folder base  17 . As can be seen in FIG. 1, the folding tube  10  is rectangularly shaped, however other shapes are suitable for the present invention. The shape of the second opening of the top support member  16  substantially corresponds to the shape of the folding tube  10 . Pillars  18  above the folder base  17  support the top support member  16 .  
         [0028]    The folding tube  10  is movably attached to the folder support apparatus  15  and is capable of manually being moved up or down. It can be appreciated that the folding apparatus  9  can be designed so that the height of the folding tube is adjusted by the aid of a machine.  
         [0029]    The lower rim  11  of the folding tube  10  has apertures for receiving pillars  18 . The lower rim  11  of the folding tube  10  can slide from a bottommost position where it is adjacent to the folder base  17  to an uppermost position where it is adjacent to the top support member  16 . The top support member  16  of the folder base  17  acts as a stop, preventing the complete withdrawal of the folding tube  10 . As can be appreciated by one skilled in the art, the lower rim  11  of the folding tube  10  can be eliminated and thus the folding tube  10  would not be movably attached in the folder support apparatus  15  and the folding tube  10  would be removable from the folder support apparatus  15 .  
         [0030]    In FIG. 2 the folding tube  10  is raised in direction A and is approximately half way between the uppermost position and the bottommost position.  
         [0031]    In FIG. 3 the folding tube  10  is completely in the uppermost position with the lower rim  11  of the folding tube  10  below and against the underside of the top support member  16  of the folder support apparatus  15 . The lower rim  11  is secured in the up position by spring metal clips  20 . Clamps or other holding devices can be used to hold the folding tube  10  in its uppermost position.  
         [0032]    As can be seen from the first three figures, the folder base  17  includes a base reservoir  19 , which is a rectangular shaped notch in the folder base  17 . It is appreciated that other shaped notches can be employed for the present invention. As will be discussed later, an airbag  41  is forcibly pushed into the base reservoir  19  and will conform to the shape of the reservoir.  
         [0033]    With reference to FIG. 4, a fold retention sheet  30 , which will be used to envelop or cover the folded airbag  41 , is placed in the base reservoir  19 . This sheet can be made of Tyvek®, paper, thin plastic, airbag material, or any other suitable material. The fold retention sheet  30  is opened as the airbag  41  inflates. The fold retention sheet  30  may be attached to a mounting plate (not shown) by including two sets of holes for receiving studs  36  from the mounting plate. FIG. 4 shows a fold retention sheet with one set of holes  31 . The other set of holes is not visible in FIG. 4. The holes are positioned to receive studs  36  from the mounting plate.  
         [0034]    As seen from FIG. 5, the folding tube  10  is slid in direction B back to the bottommost position, trapping the fold retention sheet  30  in place against the folder base  17 . A portion of the fold retention sheet  30  can be seen extending from the folder base  17 .  
         [0035]    In FIG. 6, the plunger plate  39  is preferably attached to the mounting plate of the airbag  41 ; however, the plunger plate  39  may be also directly attached to the airbag  41 . The mounting plate has a plurality of studs  36 , which correspond to the number of holes in the fold retention sheet. The studs  36  extend away from the airbag cushion. The mounting plate can be oval, round, or any other suitable shape that will be able to slide in the folding tube. It is preferred that the shape of the mounting plate corresponds to the shape of the plunger plate  39 . The plunger plate  39  is attached to the mounting plate by twisting a nut  37  or other fastener on each stud. Alternatively, the studs  36  can be tightly received in the plunger plate  39 , or can be secured by any other attachment means. The plunger plate  39  is tightly secured to the mounting plate to prevent the airbag  41  and mounting plate from dislodging from the plunger plate  39  during the folding process.  
         [0036]    The plunger plate  39  preferably has a cross-sectional surface area that corresponds to the inner cross sectional surface area of the folding tube  10 . There is enough space between the plunger plate  39  and the folding tube  10  to allow the plunger plate to move easily in the folding tube along the longitudinal axis thereof. However, the space between the plunger plate and the folding tube is not large to enough for regions of the airbag to pass into this space during the folding process, which could result in the airbag  41  being damaged and the folding apparatus being blocked.  
         [0037]    In FIG. 6, the plunger plate  39  is in position proximate the upper rim  12  of the folding tube  10 , which is in its bottommost position with the airbag cushion permitted to fall down therefrom. An end of the airbag  41  opposite to an end attached to the plunger plate  39  is the portion of the airbag that is first lowered into the folding tube  10 . The plunger mechanism  38  is introduced into the folding tube  10  after the airbag  41  is completely inside the folding tube  10 .  
         [0038]    The plunger plate  39  in FIG. 7 is forcibly lowered partially compressing the airbag  41  down into the base reservoir  19  in a direction that is essentially parallel to the longitudinal axis of the folding tube  10 . In FIG. 8, the plunger plate  39  has been completely moved through the folding tube  10  trapping the airbag  41  within the base reservoir  19  of the folder base  17 . The plunger plate  39  and the push tube  40  remain exterior to the airbag  41  during the folding process. A portion of the fold retention sheet  30  can be seen extending from the folder base  17 .  
         [0039]    Subsequently, the folding tube  10  in FIG. 9 is lifted and secured to the top rim of the folder support apparatus  15  and secured by a fastening device such as a spring metal clips  20  or completely removed so it does not slide back to its bottommost position. As can be seen, the pusher rod and plunger plate are now accessible through the open sides of the folder support apparatus  15 .  
         [0040]    Subsequently, if used, the nuts  37  or fasteners are removed from the studs  36 .  
         [0041]    The plunger plate  39  is separated from the mounting plate and slid out through the open top of the folding tube  10 . The fold retention sheet  30  is again visible. Thereafter as seen in FIG. 10, a first of the sides of the sheet is manipulated and pulled toward the center of the mounting plate so that a first set of studs  36  enters a first set of mounting holes in the sheet. This first side is laid flat on the bottom of the mounting plate. Then the opposite side of the sheet is pulled and also manipulated so that its holes receive the corresponding stud.  
         [0042]    Lastly, the cushion pack  46 , formed by the folded airbag  41  and the fold retention sheet  30 , which envelops the airbag  41 , is removed from the base reservoir  19 . FIG. 11 shows the cushion pack, which is added to an airbag module (not shown). FIG. 12 shows the underneath portion of the cushion pack. As seen from this drawing, the fold retention sheet does not completely encapsulate the airbag  41  so that inflation gas can enter the airbag in the event of a car collision.  
         [0043]    [0043]FIG. 13 shows an alternative embodiment for the present invention. The folding tube  10  in this embodiment is stationary and does not slide up and down the folder support apparatus  47 . The folder support apparatus  47  has three walls and the folder tube has an access door  45 . The access door is used to place the fold retention sheet  30  inside the folding tube  10  before the folding process commences. During the folding process, the access door is closed to prevent regions of the airbag  41  from escaping the access door. Lastly, the access door is utilized to detach the plunger mechanism  38  from the mounting plate after the airbag  41  is folded and to remove the cushion pack from the base reservoir.  
         [0044]    Many changes and modifications in the above-described embodiments of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, that scope is intended to be limited only the scope of the appended claims.