Abstract:
Described are seat units having at least one seat ( 12 ) with an upper seat back cushion ( 32 ), a lower seat back cushion ( 34 ), and a seat pan cushion ( 36 ). The at least one seat is configured to transition between a seat position and a bed position. The upper seat back cushion and the lower seat back cushion are separated by a gap ( 56 ) located between an end of each cushion when the at least one seat is in the seat position. In contrast, the ends of the cushions are flush with each other when the at least one seat is in the bed position. The seat pan cushion is positioned below a passenger&#39;s buttocks when the at least one seat transitions between the seat position and the bed position without additional adjustment by the passenger.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to and claims priority benefits from U.S. Provisional Application Ser. No. 61/976,033 (“the &#39;033 application”), filed on Apr. 7, 2014, entitled Premium Seat Functionalities. The &#39;033 application is hereby incorporated in its entirety by this reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to seat units for vehicle cabins, particular seat units comprising two seats arranged in opposing directions. 
       BACKGROUND 
       [0003]    As is well-known, business class aircraft seats offer passengers different comfort positions, from the seat position to a bed position that is substantially horizontal in flight. 
         [0004]    Business class aircraft seat units have also been designed that offer both forward and aft facing seats, which are usually overlapping with one another to take advantage of the additional space at one passenger&#39;s feet to provide additional space for another passenger&#39;s upper body. Furthermore, these arrangements typically do not provide secondary seating arrangements for visiting passengers. 
         [0005]    These business seat units are typically a conventional width used for business class passenger seats and therefore do not provide other options for passengers to be seated with their bodies in multiple orientations relative the orientation of the seat. 
         [0006]    In certain cases, multiple seating orientations may be provided by separating the backrest into an upper back cushion and a lower back cushion separated by a gap. In such examples, the upper back cushion may be fixed in place, while the lower back cushion converts into a bed position. Without inclusion of the upper back cushion in the bed position, the lower back cushion is typically not tall enough to extend the entire length of the passenger&#39;s back. As a result, the seat pan cushion is positioned below a portion of the passenger&#39;s back in the bed position, and the leg rest cushion is positioned below the passenger&#39;s buttocks and legs. As a result, the passenger must physically slide back so that his buttocks is positioned on the seat pan cushion before transitioning the seat from the bed position to the upright position to avoid falling as the leg rest cushion retracts. 
         [0007]    Thus, it may be desirable to provide a seat unit designed to accommodate multiple seating orientations through the use of separated back cushions in an upright or reclined position, while also utilizing a bed position that utilizes both back cushions to form a bed surface that allows the seat pan cushion to remain positioned below a passenger&#39;s buttocks in the bed position, as well as the upright and reclined positions. 
       SUMMARY OF THE INVENTION 
       [0008]    The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings and each claim. 
         [0009]    According to certain embodiments of the present invention, a seat unit comprises at least one seat comprising an upper seat back cushion, a lower seat back cushion, and a seat pan cushion, wherein the at least one seat is configured to transition between a seat position and a bed position, wherein the upper seat back cushion and the lower seat back cushion are separated by a gap located between an end of each cushion when the at least one seat is in the seat position, and the ends of the cushions are flush with each other when the at least one seat is in the bed position. 
         [0010]    In certain embodiments, the seat pan cushion is positioned below a passenger&#39;s buttocks when the at least one seat transitions between the seat position and the bed position without additional adjustment by the passenger. 
         [0011]    In some embodiments, the seat unit further comprises at least one footwell comprising a lower surface having an end that is positioned flush with an end of the seat pan cushion to form a horizontal bed surface in the bed position. 
         [0012]    The seat unit may further comprise two seats arranged facing one another, the two seats being substantially laterally aligned with each other and with respect to a longitudinal axis of the seat unit, and two footwells arranged facing in opposing directions so that an opening in each footwell is accessible by a passenger seated in one of the two seats that faces the opening in the footwell. In some embodiments, a portion of the seat pan cushion of one of the two seats fits into a recess below the footwell with the opening that faces away from the seat. 
         [0013]    According to some embodiments, the seat unit further comprises an armrest pivotally coupled to the lower seat back cushion by a pivot mechanism. The pivot mechanism may be coupled to a back edge of the lower seat back cushion and to a back edge of the armrest and may be configured to move the back edge of the armrest along an arc, forming a pivot axis between a front edge of the lower seat back cushion and a front edge of the armrest. In some embodiments, a deployed angle of the armrest is adjustable to achieve a substantially horizontal orientation of the armrest when the at least one seat is in an upright position or a reclined position. The pivot mechanism may comprise a friction hinge or ratchet mechanism to maintain a deployed angle of the armrest. In some embodiments, the location of the pivot mechanism allows the armrest to have the same cushioning thickness as the lower seat back cushion. 
         [0014]    In some embodiments, the seat unit further comprises a closet pivotally coupled to a location adjacent the at least one seat and is configured to pivot away from the at least one seat to provide additional space to access the at least one seat. 
         [0015]    According to certain embodiments of the present invention, a seat unit comprises at least one seat comprising an upper seat back cushion and a lower seat back cushion, wherein the at least one seat is configured to transition between an upright position, a reclined position, and a bed position, wherein the upper seat back cushion and the lower seat back cushion are separated by a gap located between an end of each cushion when the at least one seat is in the upright position and the reclined position, and the ends of the cushions are flush with each other when the at least one seat is in the bed position, and wherein the lower seat back cushion is substantially parallel with the upper seat back cushion in the upright position, the reclined position, and/or the bed position, and the lower seat back cushion may be angled with respect to the upper seat back cushion in the reclined position. 
         [0016]    According to some embodiments, the seat unit further comprises an armrest pivotally coupled to the lower seat back cushion by a pivot mechanism. The pivot mechanism may be coupled to a back edge of the lower seat back cushion and to a back edge of the armrest and may be configured to move the back edge of the armrest along an arc, forming a pivot axis between a front edge of the lower seat back cushion and a front edge of the armrest. In some embodiments, a deployed angle of the armrest is adjustable to achieve a substantially horizontal orientation of the armrest when the at least one seat is in an upright position or a reclined position. The pivot mechanism may comprise a friction hinge or ratchet mechanism to maintain a deployed angle of the armrest. In some embodiments, the location of the pivot mechanism allows the armrest to have the same cushioning thickness as the lower seat back cushion. 
         [0017]    In some embodiments, the seat unit further comprises a closet pivotally coupled to a location adjacent the at least one seat and is configured to pivot away from the at least one seat to provide additional space to access the at least one seat. 
         [0018]    According to certain embodiments of the present invention, a seat unit comprises at least one seat comprising a lower seat back cushion comprising an armrest pivotally coupled to the lower seat back cushion by a pivot mechanism, wherein the pivot mechanism is coupled to a back edge of the lower seat back cushion and to a back edge of the armrest and configured to move the back edge of the armrest along an arc, forming a pivot axis between a front edge of the lower seat back cushion and a front edge of the armrest. 
         [0019]    In some embodiments, a deployed angle of the armrest is adjustable to achieve a substantially horizontal orientation of the armrest when the at least one seat is in an upright position or a reclined position. The pivot mechanism may comprise an arcuate track and/or a friction hinge or ratchet mechanism to maintain a deployed angle of the armrest. In certain embodiments, the location of the pivot mechanism allows the armrest to have the same cushioning thickness as the lower seat back cushion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    In the following detailed description, embodiments of the invention are described referring to the following figures: 
           [0021]      FIG. 1  is a perspective view of a seat unit in a fully upright position, according to certain embodiments of the present invention. 
           [0022]      FIG. 2  is a perspective view of a seat unit in a fully upright position, according to certain embodiments of the present invention. 
           [0023]      FIG. 3  is a perspective view of the seat unit of  FIG. 2  in a fully reclined position. 
           [0024]      FIG. 4  is a perspective view of the seat unit of  FIG. 2  in a bed position. 
           [0025]      FIG. 5A  is a perspective view of a seat unit in a fully upright position, according to certain embodiments of the present invention. 
           [0026]      FIG. 5B  is a perspective view of the seat unit of  FIG. 5A  in a fully reclined position. 
           [0027]      FIG. 5C  is a perspective view of the seat unit of  FIG. 5A  in a bed position. 
           [0028]      FIG. 6A  is a perspective view of a seat unit in a fully upright position, according to certain embodiments of the present invention. 
           [0029]      FIG. 6B  is a perspective view of the seat unit of  FIG. 5A  in a fully reclined position. 
           [0030]      FIG. 6C  is a perspective view of the seat unit of  FIG. 5A  in a bed position. 
           [0031]      FIG. 7A  is a perspective view of a seat unit comprising two facing seats in the bed position, according to certain embodiments of the present invention. 
           [0032]      FIG. 7B  is a cutaway view of the lower portion of the seat unit of  FIG. 7A . 
           [0033]      FIG. 8  is a perspective view of a seat unit in the bed position showing the positioning of a portion of a seat pan cushion below a footwell, according to certain embodiments of the present invention. 
           [0034]      FIG. 9A  is a perspective view of a seat unit having an armrest pivotally coupled to a lower seat back cushion and in a deployed position, according to certain embodiments of the present invention. 
           [0035]      FIG. 9B  is a perspective view of the seat unit of  FIG. 9A  with the armrest in a stowed position. 
           [0036]      FIG. 10A  is a side view illustrating the kinematics of a seat unit with the seat unit in a fully upright position and an armrest in a deployed position, according to certain embodiments of the present invention. 
           [0037]      FIG. 10B  is a side view of the seat unit of  FIG. 10A  with the seat unit in a fully reclined position and the armrest in a deployed position. 
           [0038]      FIG. 11A  is a perspective view of a lower seat back cushion and an armrest, with the lower seat back cushion in a fully upright position, and the armrest in a stowed position, according to certain embodiments of the present invention. 
           [0039]      FIG. 11B  is a perspective view of the lower seat back cushion and armrest of  FIG. 11A , with the lower seat back cushion in a fully upright position, and the armrest in a deployed position. 
           [0040]      FIG. 11C  is a perspective view of the lower seat back cushion and armrest of  FIG. 11A , with the lower seat back cushion in a fully reclined position, and the armrest in a deployed position. 
           [0041]      FIG. 11D  is a perspective view of the lower seat back cushion and armrest of  FIG. 11A , with the lower seat back cushion in a fully upright position, and the armrest in an unlocked position. 
           [0042]      FIG. 12A  is a perspective view of a pivot mechanism used to couple an armrest to a lower seat back cushion, with the pivot mechanism in a deployed position, according to certain embodiments of the present invention. 
           [0043]      FIG. 12B  is a perspective view of the pivot mechanism of  FIG. 12A , with the pivot mechanism in a stowed position. 
           [0044]      FIG. 13  is a perspective view of a seat unit comprising a pivoting closet, according to certain embodiments of the present invention. 
           [0045]      FIG. 14  is a top view of the seat unit of  FIG. 13  with the closet in an open position. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. 
         [0047]    While the embodiments of seat units may be described with reference to an aircraft cabin, they are by no means so limited. In fact, the seat units may be used in conjunction with any type of vehicle cabin or otherwise as desired. 
         [0048]    According to certain embodiments of the present invention, as illustrated in  FIGS. 1-14 , a seat unit  10  comprises at least one seat  12  and at least one footwell  14 , wherein the seat  12  is arranged facing an opening  16  in the footwell  14 . 
         [0049]    Each seat  12  comprises an upper seat back cushion  32 , a lower seat back cushion  34 , a seat pan cushion  36 , and, optionally, a leg rest cushion  38 , which are partially surrounded by a shell  40 . Furthermore, each seat  12  is configured to convert between a seat position that ranges from a fully upright position (as best illustrated in  FIGS. 1-2, 5A, 6A ,  9 A- 9 B, and  10 A) to a fully reclined position (as best illustrated in  FIGS. 3, 5B, 6B, and 10B ), and a bed position that is substantially horizontal in flight (as best illustrated in  FIGS. 4, 5C, 6C, 7A-7B, and 8 ). 
         [0050]    In the seat position (also referred to as a “TTL” or taxi, take-off, landing position), the upper seat back cushion  32  is positioned adjacent a rear wall  44  of the shell  40  at a location that is above and slightly spaced apart or separated from the lower seat back cushion  34  by a gap  56 . The gap  56  is configured to provide an arm rest over the lower seat back cushion  34 . 
       1. Seat Kinematics 
       [0051]    As best illustrated in  FIGS. 5A-5C and 6A-6C , the upper seat back cushion  32  is coupled to the lower seat back cushion  34  by a kinematic that is configured to convert the seat  12  into the bed position by lowering the upper seat back cushion  32  until it closes the gap  56  between the upper seat back cushion  32 , and the upper seat back cushion  32  contacts the lower seat back cushion  34 . The kinematic then transitions the seat pan cushion  36  toward the footwell  14 , and rotates and transitions the seat back cushions  34 ,  32  into a horizontal position adjacent the seat pan cushion  36  so that the cushions are positioned adjacent one another so as to form a substantially horizontal bed surface  42  in the bed position. The kinematic therefore provides a smooth transition between bed and seat positions, without the need for a passenger to adjust his position on the seat  12  other than to extend his legs when transitioning into the bed position and bend his legs when transitioning into the seat position. 
         [0052]    In some embodiments, the kinematic may also be configured to raise the leg rest cushion  38  into a substantially horizontal position so that the leg rest cushion  38  may also form part of the bed surface  42 . However, in other embodiments, the leg rest cushion  38  may remain in the stowed position below the bed surface  42 . 
         [0053]    In these embodiments, the kinematic that adjusts the height of the upper seat back cushion  32  is also able to adjust the angled position of the seat back cushions  32 ,  34  (while the seat back cushions  32 ,  34  are positioned adjacent one another) to provide appropriate back support over a range of recline angles, which is not possible if the upper seat back cushion were fixed in a stationary position on the rear wall  44  of the shell  40 . 
         [0054]    For example,  FIGS. 5A-5C  illustrate certain embodiments of the kinematic transitioning the seat  12  between seat and bed positions. In  FIG. 5A , the seat  12  is in a fully upright position, and the gap  56  is greatest between the upper seat back cushion  32  and the lower seat back cushion  34 , and may range from 50-400 mm in the fully upright positon. In  FIG. 5B , the seat  12  is in a reclined seat position, wherein the gap  56  is smaller. In the fully reclined position, the gap  56  may range from 0-400 mm. Finally, in  FIG. 5C , the seat is in the bed position, and the gap  56  has been eliminated by bringing the cushions  32 ,  34  flush with one another. 
         [0055]    In  FIGS. 6A-6C , the kinematic is configured to provide different lifting angles for the upper seat back cushion  32  and the lower seat back cushion  34 . For example, in  FIG. 6A , the seat  12  is in a fully upright position, the gap  56  is in the greatest position (and may range from 50-400 mm in the fully upright positon), and the cushions  32 ,  34  are arranged in substantially the same plane (substantially the same position as  FIG. 5A ). However, in  FIG. 6B , the upper seat back cushion  32  is lowered so that the gap  56  is smaller (ranging from 0-400 mm in the fully reclined position) but remains in substantially the same vertical orientation as  FIG. 6A , whereas the lower seat back cushion  34  is angled relative to the upper seat back cushion  32  by an angle α, which may range from 1-30 degrees. The angled position of the lower seat back cushion  34  increases the available space in the reclined position. Finally, in  FIG. 6C , the seat is in the bed position, the gap  56  has been eliminated, and the cushions  32 ,  34  are once again arranged in substantially the same plane (substantially the same position as  FIG. 6C ). 
         [0056]    In certain embodiments, the kinematic may provide an option to adjust the angle of the lower seat back cushion  34  in the reclined position between the position shown in  FIG. 5B  to the position shown in  FIG. 6B , or any other suitable range of angles. 
       2. Overlapping Seat Arrangement 
       [0057]    In certain embodiments, as illustrated in  FIGS. 3-4, 7A-7B, and 13-14 , the seat unit  10  may comprise two seats  12 , wherein the seats  12  are arranged to face one another, and a partition  18  is positioned between the seats  12 . Each seat  12  may be arranged so that it is substantially laterally aligned with the other seat  12  with respect to the longitudinal axis Y of the seat unit  10 . While the seat units  10  may be discussed with reference to two seats  12 , they are by no means so limited. For example in certain embodiments, the seat unit  10  may comprise one seat  12  with one footwell  14 . 
         [0058]    Each footwell  14  may comprise a stationary lower surface  20  and vertically oriented sides  22 ,  24 . In certain embodiments, the vertically oriented side  22  of each footwell  14  may form at least a portion of an outer wall of the partition  18 . As a result, the vertically oriented sides  22  may be arranged substantially parallel to a longitudinal axis of the cabin. 
         [0059]    In some embodiments, the two footwells  14  share the same inner vertically oriented side  24 . The side  24  may be laterally angled so that the lateral dimension of each footwell  14  is wider at the opening  16  closer to the mating seat  12 , and narrower at an opposing end of the footwell  14 . 
         [0060]    Each footwell  14  may be further enclosed by an upper surface  26  and a rear surface  28 . The upper surface  26  of each footwell  14  may also serve as a table top, work surface, dining surface, cocktail table, or other usable surface for a passenger seated in the opposing seat  12  (i.e., the seat  12  that does not have access to the opening  16  in the footwell  14 ). The portion of the footwell  14  that is enclosed by the upper surface  26  and the rear surface  28  may extend into the space occupied by a passenger seated in the opposing seat  12 . 
         [0061]    The space allotted to each passenger in the seat unit  10  may be further separated by an upper wall  30  that forms a portion of the partition  18  that extends above the footwells  14  and provide a location for mounting monitors, other electronic devices, and/or other stowage compartments. 
         [0062]    The stationary lower surface  20  of each footwell  14  forms a lower surface of the enclosed portion, which may be configured to extend beyond the enclosed portion and upper wall  30  into the space of a passenger seated in the mating seat  12 . The sides  22  and  24  may also be configured to extend a similar distance into the space of the passenger seated in the mating seat  12 . 
         [0063]    The stationary lower surface  20  of each footwell  14  is positioned at a height that substantially aligns and mates with the leg rest cushion  38  in the bed position so that the combination of the stationary lower surface  20 , the leg rest cushion  38 , the seat pan cushion  36 , and the seat back cushions  34 ,  32  form the bed surface  42  that utilizes substantially all of the available space allocated within the seat unit  10  for each seat  12 . 
         [0064]    In the embodiments where a second footwell  14  (positioned with the opening  16  toward an opposing seat  12 ) extends into the space occupied by a passenger seated in the seat  12 , in the bed position, a portion of the seat pan cushion  36  may be positioned below the second footwell  14 . To accomplish this arrangement, the footwell  14  may be shaped with a recess  60  that is configured to allow the portion of the seat pan cushion  36  to extend into the recess in the bed position, as best shown in  FIGS. 7A-7B and 8 . In other embodiments, an additional kinematic may be used to lower a portion of the seat pan cushion  36  so that it extends below the second footwell  14 . 
       3. Armrest Integration 
       [0065]    As best illustrated in  FIG. 1 , the seat  12  has a width that is wider than a conventional business class passenger seat, the wider dimension allowing a passenger to be seated in multiple orientations. For example, a passenger may be seated so as to have his or her body oriented in a direction that is substantially parallel to the longitudinal axis Y of the seat unit  10 , or the passenger may be seated so as to have his or her body oriented in a direction that is angled (or even substantially perpendicular) to the longitudinal axis Y of the seat unit  10 . 
         [0066]    In order to accommodate the various seat arrangement options, a variety of locations for armrests  50  have been incorporated into the seat  12 . 
         [0067]    First, as described above, the gap  56  between the upper seat back cushion  32  and the lower seat back cushion  34  allows a passenger to use to the top of the lower seat back cushion  34  as an armrest when the passenger is seated at an angle to the longitudinal axis Y. 
         [0068]    Additionally and/or alternatively, as illustrated in  FIGS. 1-4 , an armrest cushion  50  may be positioned on one or both side walls  48  of the shell  40  that is below and slightly spaced apart from the headrest cushion  46 . One or both armrest cushions  50  may be positioned at a height that substantially aligns with a height of the lower seat back cushion  34  when the seat  12  is in the upright seat position or may be at different heights as needed or desired. 
         [0069]    In certain embodiments, as best illustrated in  FIGS. 8, 9A-9B, 10A-10B, 11A-11D, and 12A-12B , at least one adjustable armrest  62  may be incorporated into the lower seat back cushion  34  to provide additional armrest support options. Because the armrest  62  is configured to stow substantially flush with the lower seat back cushion  34 , the armrest  62  appears to be pivotally coupled to the lower seat back cushion  34  proximate a pivot axis  64  positioned at the location where a front edge  66  of the armrest  62  and a front edge  68  of the lower seat back cushion  34  join. 
         [0070]    A pivot mechanism  70  is not included at the pivot axis  64  because the pivot mechanism  70  would form a hard object that could easily be detected through the surface of the armrest  62  in this location, particularly when the seat  12  is in the bed position. As a result, the pivot mechanism  70  may be positioned on the opposite side of the armrest  62  and the lower seat back cushion  34  at a location where a back edge  72  of the armrest  62  and a back edge  74  of the lower seat back cushion  34  join. By locating the pivot mechanism  70  behind the armrest  62  and the lower seat back cushion  34 , the armrest  62  has the same thickness and cushioning as the lower seat back cushion  34 , which provides a comfortable experience for the passenger positioned on the seat  12  in the bed position regardless of whether he or she is lying on the armrest  62  or the lower seat back cushion  34 . 
         [0071]    In order to use the back edge position to create the front edge pivot axis  64 , the pivot mechanism  70  may be configured with an arcuate track  76  that moves the back edge  72  of the armrest  62  about the virtual pivot axis  64  along an arc. The track  76  may be coupled to a fixed location on a support for lower seat back cushion  34  and positioned so that a lower end  96  of the track  76  is positioned proximate the back edge  74  of the lower seat back cushion  34 . 
         [0072]    To couple the armrest  62  to the pivot mechanism  70 , a support plate  80  may be fixedly coupled to a lower surface  82  of the armrest  62  and slidingly coupled to a base plate  92 . In some embodiments, the base plate  92  may be pivotally coupled to a pivot location  94  on the framework of the track  76 . The support plate  80  may also be coupled to a first end  84  of at least one arcuate arm  86  at a location that is proximate the back edge  72  of the armrest  62 . 
         [0073]    A projection  88  may then be coupled to or configured to extend from a second end  90  of the arm  86 . In some embodiments, the projection  88  may be positioned between second ends  90  of a pair of arms  86 . The arm  86  may then be coupled to the track  76  by positioning the projection  88  within the track  76 . 
         [0074]    In certain embodiments, the shapes of the arms  86  and track  76  are complementary so that when the projection  88  is positioned at an upper end  98  of the track  76 , the arms  86  are positioned substantially alongside the track  76 . A person of ordinary skill in the relevant art will understand that other suitable shapes of the arms  86  and track  76  may be used that provide the desired rotational movement of the armrest  62 . 
         [0075]    In a stowed position, as illustrated in  FIGS. 8, 9B, and 11A , the projection  88  is positioned proximate the upper end  98  of the track  76 , which in turn positions the arms  86  substantially alongside the track  76  so that the first end  84  of the arm (and thus the back edge  72  of the armrest  62 ) is positioned alongside the lower end  96  of the track  76  (and thus the back edge  74  of the lower seat back cushion  34 ). In the stowed position, the base plate  92  is also rotated into a position that is substantially parallel to the position of the lower seat back cushion  34 , and the support plate  80  is positioned substantially proximate the pivot location  94 . 
         [0076]    To deploy the armrest  62  into one of the deployed positioned illustrated in  FIGS. 9A, 10A-10B, 11B-11C , the armrest  62  is rotated away from the stowed position toward the front of the seat  12 . With this frontward rotation, the projection  88  moves along the track  76  toward the lower end  96  of the track  76 . This movement also causes the arms  86  to move toward the front of the seat  12  and away from the track  76 , thus extending the combined arcuate length of the track  76  and the arms  86 . In certain embodiments, the arcuate length between the upper end  98  and the lower end  96  of the track  76  is approximately 90 degrees, but can range from 60-120 degrees. 
         [0077]    The frontward movement of the armrest  62  also causes the base plate  92  to rotate in a frontward direction away from the position that is substantially parallel to the position of the lower seat back cushion  34 . However, because the base plate  92  is rotating about the fixed pivot location  94  and the support plate  80  is moving via the forward and angular motion of the arms  86 , the support plate  80  slides frontward along the base plate  92  and away from the pivot location  94 . Because the base plate  92  is shaped to continue to extend along a substantial surface of the support plate  80 , the armrest  62  is supported and stabilized by the base plate  92 . 
         [0078]    To hold the armrest  62  in any of the desired deployed positions, a friction hinge (or any suitable ratchet mechanism)  100  may be incorporated into the pivot location  94 . In some embodiments, the device  100  may be designed to eliminate the torque required to move the device  100  in the frontward direction, while requiring an excessive torque to overcome the hinge resistance torque necessary to move the device  100  in the rearward direction until the device  100  reaches an unlocking position (as shown in  FIG. 11D ). In the unlocking position, the device  100  is extended to a position where the torque required to move the device  100  in the rearward direction is eliminated until the device  100  has returned to the stowed position. In other embodiments, the armrest  62  may be secured into place after adjustment by a variety of mechanisms, including but not limited to a securing mechanism, adjustable fastener, or button mechanism. 
         [0079]    The armrest  62  is also configured to have a range of deployed positions to accommodate a range of reclined positions of the lower seat back cushion  34 . For example, because it is desirable for the armrest  62  to be maintained in a substantially horizontal orientation, the pivot mechanism  70  is configured to allow a deployed angle between the armrest  62  and the lower seat back cushion  34  to be adjusted to accommodate different reclined positions. In other words, as illustrated in  FIG. 10A , in the upright position, the armrest  62  forms a deployed angle β with the lower seat back cushion  34 , where the deployed angle β may range from 60-100 degrees. As illustrated in  FIG. 10B , in the fully reclined position, the armrest  62  forms a deployed angle γ with the lower seat back cushion  34 , where the deployed angle γ may range from 35-95 degrees. 
       4. Headrest Design 
       [0080]    As illustrated in  FIGS. 1-4 , the shell  40  may further comprise at least one headrest cushion  46  positioned on one or both side walls  48  of the shell  40 . The headrest cushion  46  may be vertically aligned with the fully raised height of the upper seat back cushion  32  or may be at different heights as needed or desired. 
         [0081]    In some embodiments, the shell  40  may only comprise one side wall  48  and/or may comprise a second side wall  48  that only extends to a lower height, such as a location of an armrest cushion  50 , which is described in more detail below. In some embodiments, as shown in  FIG. 1 , both side walls  48  may be shortened to a lower height. 
         [0082]    The elimination and/or minimization of the height of one or both side walls  48  may utilized to reduce the weight of the seat unit  10 . For example, in embodiments where the location of the second side wall  48  is adjacent a wall of the cabin, the additional structural separation and/or full height of the side wall  48  is not needed. 
         [0083]    In these embodiments, the headrest cushion  46  may be attached to the shell  40  via a projection  58  that extends from the rear wall  44  of the shell  40 . The projection  58  may be configured to extend from the rear wall  44  into the space where the headrest cushion  46  is to be positioned and, in some embodiments, may be positioned above the shortened side wall  48 . 
       5. Closet 
       [0084]    In certain embodiments, as shown in  FIGS. 13-14 , the seat unit  10  comprises a closet  52  for each seat  12 . The closet  52  may be positioned adjacent one or both of the side walls  48  of each seat  12 , such as the side wall  48  that is adjacent an aisle  54  of the cabin. In these embodiments, the closet  52  may comprise the entire side wall  48  or may only be attached to an outer surface of the side wall  48 . 
         [0085]    In certain embodiments, the closet  52  is configured to pivot into the aisle  54  (similar to a door), which provides additional space to access the seat  12  from the aisle, with is particularly helpful for disabled passengers. The closet  52  is mounted on hinges that are locked in place until additional access room is needed. 
         [0086]    Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and sub-combinations are useful and may be employed without reference to other features and sub-combinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications may be made without departing from the scope of the claims below.