Abstract:
A hybrid seat pan and diaphragm apparatus includes a seat pan that has a concave portion and a diaphragm positioned at an occupant-facing side of the seat pan and stretched across the seat pan at a first distance above the concave portion of the seat pan.

Description:
CROSS-REFERENCE RELATED APPLICATIONS 
       [0001]    This is a non-provisional and claims the benefit under 35 USC §119(e) of U.S. Patent Application Ser. No. 62/145,617 filed Apr. 10, 2015, hereby incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The invention relates to seating structures and, more particularly, to seating structures that include a suspension diaphragm for receiving an occupant&#39;s weight. 
         [0004]    2. Discussion of Art 
         [0005]    Aircraft seats commonly have a back structure and a seat bottom structure that are fitted with cushions and upholstery. The seat bottom carries the majority of the passenger&#39;s weight and is therefore of particular concern with regard to comfort. The seat bottom is located above structural members of the seat frame specifically the beam elements. To support the passenger above the hard, uneven seat structure, the seat bottom portion of the seat often employs either an elastomeric fabric diaphragm or a rigid pan that is covered with cushioning. Each method provides certain comfort benefits but neither is without shortcomings. 
         [0006]    Rigid pans provide a consistent platform for the passenger and can have contoured shapes that address ergonomic needs. However, they are hard and require thicker cushions to make the occupant comfortable. Thicker cushions reduce the passenger&#39;s living space and increase weight. 
         [0007]    Diaphragm systems typically comprise a fabric suspension tensioned across a frame. A cushion is placed on top of the diaphragm to distribute loads and pad areas where the frame might be felt by the passenger. Being flexible, the diaphragm has inherent comfort advantages. However, even if tightly tensioned, the diaphragm is often deflected by the passenger enough to cause contact with structural parts of the seat such as the beam. This contact is often felt by the passenger, causing discomfort. As with rigid pans, the correction is too often a thicker, heavier cushion. At a time when space is valuable to the passenger and weight means higher costs to the airline, thicker cushions are undesirable. 
       BRIEF DESCRIPTION 
       [0008]    Embodiments of the invention provide a seat apparatus, which includes a seat chassis that has side frames connected by a cross beam; a seat pan above the cross beam; and a tensioned diaphragm above the seat pan. Other embodiments provide hybrid seat pan and diaphragm apparatus, which includes a seat pan that has a concave portion and a diaphragm positioned at an occupant-facing side of the seat pan and stretched across the seat pan at a first distance above the concave portion of the seat pan. 
         [0009]    The first distance may be sufficient so that an occupant&#39;s weight does not deflect the diaphragm to touch the seat pan. On the other hand, the seat pan may restrict deflection of the diaphragm under an occupant&#39;s weight. The seat pan may be contoured to reduce contact pressure of an occupant&#39;s weight. Or the seat pan may have a cutout portion central to the concave portion, so that an occupant&#39;s weight can deflect the diaphragm through the cutout portion. In any case, the seat pan restricts the diaphragm from contacting the cross beam of the seat chassis. In certain embodiments, a vibration absorbing pad may be disposed between and in contact with the seat pan and the cross beam. 
         [0010]    The diaphragm may be stretched across the seat pan between stiffeners that are fastened to the seat pan by rivets. Side edges of the diaphragm may be wrapped around the stiffeners and stitched together to capture the stiffeners. Alternatively, the diaphragm may be tensioned across the side frames of the seat chassis. 
         [0011]    Thus, the described hybrid design combines benefits of both a rigid pan and a fabric suspension to preserve comfort without resorting to a thick cushion. The hybrid comprises a special frame and an elastomeric fabric diaphragm stretched laterally across the frame and/or tensioned fore and aft. Beneath the diaphragm is a specially shaped partial pan or pan portion that is attached integrally to the frame and is positioned to act as a barrier between the passenger and the beam structure that supports the frame. The shape and contour of this abbreviated pan provides a surface that is determined by ergonomic studies and designed to minimize discomfort. 
         [0012]    With the described hybrid seat pan, the passenger still deflects the diaphragm but instead of contacting the beam or other hard parts of the seat&#39;s structure, comes to rest upon the specially shaped pan portion. The support of the diaphragm suspends the passenger enough to reduce the effective weight that is applied where the passenger and pan portion make contact. That results in lower contact pressures and less discomfort. Less padding is needed and cushions can be kept thinner. The thinner cushions used with this hybrid design preserve living space, minimize weight and offer opportunities to reduce material and manufacturing costs. 
         [0013]    Other benefits of the hybrid system include increased durability. The thick cushion on a rigid pan system breaks down much quicker than typical elastomeric diaphragms, exposing the passenger to high contact pressures with the pan. The hybrid diaphragm is long lasting and the shaped pan portion is not subject to wear. 
         [0014]    Certain exemplary embodiments, as briefly described above, are illustrated by the following figures. 
     
    
     
       DRAWINGS 
         [0015]      FIG. 1  shows in side view a seat assembly comprising a seat chassis that supports a hybrid seat pan and diaphragm assembly according to an embodiment of the invention. 
           [0016]      FIG. 2  shows in side view the hybrid seat pan and diaphragm assembly of  FIG. 1 . 
           [0017]      FIG. 3  shows in plan view the hybrid seat pan and diaphragm assembly of  FIGS. 1 and 2 . 
           [0018]      FIG. 4  shows in side sectional view hybrid seat pan and diaphragm assembly of  FIGS. 1-3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Referring to  FIG. 1 , a seat chassis  10  comprises side members  12  and cross beams  14 . A seat assembly  16  rests in the seat chassis  10  above the cross beams  14 . It is a well known problem that a rearward portion of a conventional seat assembly can deform downward under an occupant to contact a rearward one of the cross beams  14 . This contact can result in discomfort for the occupant. As discussed above, efforts to mitigate such discomfort typically have relied upon thick and relatively heavy cushions. According to the present invention, however, a relatively thin weight-saving cushion  18  is provided in combination with a hybrid seat pan and diaphragm assembly  16 . 
         [0020]    Referring to  FIGS. 2 and 3 , the hybrid seat pan and diaphragm assembly  16  comprises a pan frame  22  that has a strong perimeter. The pan frame  22  is separate from the side members  12  of the seat chassis  10 . Thus, the hybrid assembly  16  can be dropped into the seat chassis and can be movably supported in the seat chassis. For example, the hybrid assembly  16  can be slidably supported for fore-and-aft movement within the seat chassis  10 . 
         [0021]    The perimeter of the pan frame  22  supports a contoured pan-like member or pan portion  24 , which is mounted to bridge across the pan frame  22 . The pan portion  24  could be formed as part of the pan frame  22 . Alternatively, the pan portion  24  can be formed as a molded part that is bonded or otherwise attached to the pan frame  22 , including as a drop-in piece. 
         [0022]    Above the pan portion  24 , a flexible diaphragm  26  is tensioned across the pan frame  22 . Referring to  FIGS. 3 and 4 , side edges of the diaphragm  26  are folded around stiffeners  28  and are secured to the stiffeners by stitches  30 . The diaphragm  26  is stretched and then attached to the perimeter of the frame  22  by rivets  32  that pass through the stiffeners  28 . The riveted attachments tightly tension the diaphragm  26  into a position approximately one to two inches offset from the pan portion  24 . Even when deflected toward the pan portion  24  by an occupant&#39;s weight, the tensioned diaphragm  26  absorbs the weight in a low-pressure manner so as to render an occupant comfortable by comparison to sitting directly on a conventional pan-and-cushion seating arrangement. For additional comfort, the pan portion  24  may include a cut-out  33 , which can accommodate large deflections of the diaphragm  26 . 
         [0023]    Alternatively, the diaphragm  26  may be attached to and tensioned across the side members  12  of the seat chassis  10 . That is, the diaphragm  26  would not be attached directly to the pan frame  22 . This arrangement would be used when the pan portion  24  is not required to move within the seat chassis  10 . 
         [0024]    In place of the riveted attachments, the diaphragm  26  equally could be attached to the pan frame  22  (or to the seat chassis side members  12 ) in a manner substantially as shown in FIGS. 4 and 5 of co-pending and commonly owned U.S. patent application Ser. No. 14/244,524, hereby incorporated by reference in its entirety. An ordinary skilled worker may contemplate other modes of attaching the diaphragm  26  to the pan frame  22 . 
         [0025]    Referring back to  FIG. 1 , the hybrid seat pan portion  24  and the diaphragm  26  are installed into the seat chassis  10  as the completed subassembly  16 . The subassembly  16  then is fitted with the cushion  18 . The mountings (not shown) of the subassembly  16  can be designed as needed to accommodate specific structural features of a particular seat. The pan portion  24  is located above the cross beams  14  of the seat chassis  10 . The cut-out  33  is positioned away from the cross beams  14 . Thus, even when the diaphragm  26  has been deflected by an occupant&#39;s weight, the pan portion  24  prevents the diaphragm contacting the cross beams  14 , brackets, braces, or other components of the seat chassis  10 . The cut-out  33  may be substantial in size. Indeed, the pan portion  24  may be only a contoured member that disperses contact of the diaphragm  26  against the cross beam  14 . 
         [0026]    In certain designs the pan portion  24  can rest in contact with the rearward beam  14 , separated by a vibration absorbing pad  34 . Such a pad is not needed in designs where the pan portion  24  remains above and apart from the beam  14 . 
         [0027]    The hybrid seat pan and diaphragm assembly  16  is described as a seat bottom structure. The principle of using a seat pan to control the displacement of a seat suspension diaphragm could also be applied to a seat back. While the comfort enhancing effects are more dramatic with seat bottoms, the hybrid seat pan and diaphragm can be useful on certain seat backs, particularly in applications such as lie flat seats or seats where the back has substantial recline. Accordingly, terms of direction such as “above” are used only for convenience of description and are not meant to limit the invention to any particular orientation or arrangement. 
         [0028]    Concomitant to their comfort benefits, the hybrid seat pan and diaphragm also permit use of thinner cushions, thereby reducing the overall weight of a seat assembly. 
         [0029]    The hybrid seat pan and diaphragm assembly  16  is described relating to aircraft seating. However, it is easily understood how the arrangement could be used with similar benefits for seating of all types. 
         [0030]    Although exemplary embodiments of the invention have been described with reference to attached drawings, those skilled in the art nevertheless will apprehend variations in form or detail that are consistent with the scope of the invention as defined by the appended claims.